METHOD OF FORMATION OF A DIGITAL PRINT ON A PANEL

专利摘要:
method of forming a fingerprint on a panel and equipment to provide a fingerprint. the invention relates to a method and equipment for forming a digital print by applying dry dyes (7) on a surface (2) of a panel (1), binding a part of the dyes (7) with a binder (11 ), and removing unbound dyes (7) from the surface (2).
公开号:BR112015016163B1
申请号:R112015016163-4
申请日:2014-01-10
公开日:2021-08-17
发明作者:Darko Pervan；Tony Pervan
申请人:Ceraloc Innovation Ab；
IPC主号:

专利说明:

Technical Field
[001] The description, in general, relates to the field of digitally created decorative surfaces for building panels, such as floor and wall panels. The description relates to a method and equipment for applying and binding powder-based dyes such that a fingerprint is formed on such surfaces. Application field
[002] Embodiments of this invention are particularly suitable for use on floors, which are formed into floor panels comprising a core or a body, the decorative layer, and preferably a structured transparent wear-resistant layer above the layer. decorative. Preferred embodiments are conventional laminate flooring, powder-based flooring, wood flooring, plastic-based LVT flooring, and ceramic tile. The following description of techniques, problems of known technology, and objectives and characteristics of the invention will therefore be, as a non-restrictive example, aimed above all in this field of application and, in particular, in floors that are similar to conventional laminate floors, or floors with a resilient surface layer.
[003] It should be emphasized that embodiments of the invention can be used to produce a digital image and/or a digitally formed structure on any surface, but flat panels, such as, for example, building panels, in general, building panels. wall, ceilings, furniture components, and similar products that generally have large surfaces with advanced decorative designs are preferred. The basic principles of the invention can be used to apply a print on paper, sheets, textiles, metals, solid wood, wood veneer, wood-based sheet materials, cork, linoleum, polymer material, ceramics, paper. wall, and similar surfaces. Background
[004] The following description is used to describe the background and products, materials and production methods that may comprise specific parts of preferred embodiments in the description of this invention.a) Laminate Flooring.
[005] Most all laminate floors are produced according to a production method commonly referred to as Direct Press Laminate (DPL). Such laminate floors have a 6-12mm core of fiberboard, a 0.2mm thick laminate top decorative surface layer, and a 0.1-0.2mm thick laminated lower stabilizer layer, plastic, paper, or similar materials.
[006] The surface layer of a laminate floor is characterized in that the decorative and wear properties are generally obtained with two separate layers of paper, one above the other. The decorative layer is generally a printed paper, and the wear layer is a transparent overlay paper, which comprises small particles of aluminum oxide.
[007] Decor paper is the most critical of the laminating papers as it gives the visual appearance of the laminate. The weight of decor paper is generally in the range of 60 - 150 g/m2.
[008] Overlay paper is generally thinner with a weight of about 20 - 50 g/m2, and is produced from pure cellulose, which is based on delignified pulp. The overlay paper becomes almost completely transparent after lamination, and the appearance of the paper decor is visible. Thicker overlay papers with a considerable amount of aluminum oxide particles can give high wear resistance. The downside is that they are less transparent, and the decorative pattern is covered with a gray layer that breaks up the printed pattern.
[009] Printing decorative papers is very cost efficient. Rotogravure presses with impression cylinders that can have a width of 3 meters and that can operate with a speed of up to 600 m/min are used. Printing cylinders are generally produced by conventional mechanical engraving. Recently, digital laser engraving has been introduced, which allows for faster decoration development, and provides better decoration quality. Solvent-free inks with organic pigments are often used, and excess ink is recycled.
[0010] The printed decorative paper and overlay are impregnated with melamine formaldehyde resins, generally referred to as melamine resins, and laminated to an HDF core in large batch or continuous laminate presses where the resin cures under high heat ( about 170°C) and pressure (4-6 MPa (40 - 60 bar)), and the papers are laminated to the core material. An embossed press plate or pick-up belt forms the surface structure. Sometimes a structured paper is used as a press die. Engraving is on high quality floors produced in registration with the project. The engraving depth is limited to 0.1 - 0.2 mm (100 - 200 micron).
[0011] Laminate floors can also be produced with direct printing technology. One advantage is that the pressing operation can be avoided, and that no printed paper is needed to provide a decorative surface. Hydroprint inks are used to print the decor by a multi-color roller printing press on a pre-sealed core, and the print is covered with a protective transparent wear layer which can be an overlay, a plastic sheet, or a varnish. The production process is preferably complicated, and is only cost efficient in very large production volumes.
[0012] Direct printing technology can be replaced with digital printing technology that is much more flexible, and small production volumes can be economically manufactured. The difference between these two methods is mainly the printing step where the printing rollers are replaced by a digital non-contact printing process.
[0013] Digital printing can also be used for printing onto a sheet of paper that is used in conventional laminate production, and laminated under heat and pressure. Printing can be done before or after impregnation. Such printing before impregnation is complicated, as the paper can be swollen and shrunk during the printing and impregnation step, and small amounts are not cost effective to impregnate. Printing after impregnation on a melamine impregnated paper is very difficult as pigments applied to a melamine surface float during the pressing step when the melamine resin is in a liquid state. Such problems can be partially solved with a method where a raw paper, preferably comprising a base color, is applied and fixed to the core before printing, and impregnated paper or melamine powder is applied under and/or on the raw paper, such that resins from the impregnated papers penetrate into the raw paper during the pressing step.
[0014] Laminate floors can also have a surface of paper sheets, or plastic sheets, and such sheet materials can also be digitally printed. A clear, wear-resistant protective layer, which is typically a polyurethane varnish, is used to cover the printed decoration. b) Powder-based floors (WFF)
[0015] Recently, new "paper-free" floor types have been developed with solid surfaces comprising a substantially homogeneous powder mixture of fibers, binders, and wear-resistant particles, hereinafter referred to as WFF (Wood Fiber Floor) .
[0016] The powder mixture may comprise aluminum oxide particles, melamine formaldehyde resins, and wood fibers. In many applications, decorative particles, such as, for example, color pigments, are included in the mix. In general, all these materials are applied in dry form as a powder mixed into an HDF core, and cured under heat and pressure to a solid layer of 0.1 - 1.0 mm. The powder is, before pressing, stabilized with moisture and IR lamps, such that it forms an upper skin layer similar to a paper layer, and this prevents the powder from being blown off during pressing. Melamine formaldehyde powder and wood fibers can be replaced by thermoplastic particles.
[0017] Several advantages over known technology, and especially over conventional laminate flooring, can be obtained, such as increased wear and impact resistance, deep engraving, increased production flexibility, and lower costs. An engraving depth of 0.2 -0.7 mm can easily be achieved.
[0018] Powder technology is very suitable for producing a decorative surface layer, which is a copy of stone and ceramics. In the past, it was more difficult to create projects such as wooden decorations. However, recently digital powder printing has been developed, and it is possible to create very advanced designs of any kind by injecting ink into the powder before pressing. Problems related to paper impregnation can be completely eliminated as no impregnation is required. The surface structure is produced in the same way as for laminate flooring by a structured press plate, a pick-up belt, or an embossed matrix paper that is pressed against the dust. An advantage compared to other digital printing technologies is that the powder provides a base color, and no protective layer is needed above the print as the ink can penetrate the powder. Penetration is, however, preferably limited, as the ink drops will be attached to the first particle they collide with, mainly the wood fibres. Increased wear resistance can be achieved if several layers of printed powder are applied to each other, or if an overlay of powder is used as a protective layer applied over the fingerprint.c) Melamine formaldehyde resin.
[0019] A basic substance in Laminate and WFF floors is thermosetting melamine formaldehyde resin which is used as a binder. Melamine resin, or melamine formaldehyde resin (generally shortened to melamine), is a hard thermosetting plastic material produced from melamine and formaldehyde by polymerization. Such a resin, hereinafter referred to as melamine, comprises three basic stages. The stages, stage A, stage B, stage C, are described in Principles of Polymerization, George Odian, 3rd edition, which is hereby incorporated by reference, including particularly pages 122 to 123. Uncured first stage A is obtained when melamine, formaldehyde and water, are boiled to a liquid substance with a dry content of about 50%. The semi-cured second stage B is obtained when the liquid resin is used to impregnate, for example, an overlay paper which, after application of the liquid resin, is dried with heat. The molecules start to crosslink, but the resin is still possible to cure in a final stage if drying of the resin is carried out for a preferably short time, eg one minute, and with a heat of about 90 - 120°C.
[0020] Stage B can also be obtained by spraying the liquid resin over hot air, such that the drops are dried, and a dry semi-cured melamine formaldehyde powder is obtained, which comprises small round spherical particles with a diameter of about 30 - 100 microns (0.03 -0.10 mm).
The final fully cured stage C is obtained when, for example, melamine impregnated paper, or WFF powder, is heated to about 160°C under pressure for 10 - 20 seconds. The dry melamine formaldehyde resin becomes softer, melts and cures to a fixed shape when the temperature rises during pressing. Cure is dependent on temperature and heating time. Curing can be achieved at lower temperatures for a longer time, or at higher temperature for a shorter time. Spray dried melamine powder can also be used at high temperature. d) Wooden floors.
[0022] Hardwood floors are produced in many different ways. Traditional solid hardwood floors developed in engineered floors with layers of wood applied to a core produced from veneer, HDF or plywood. Most such floors are distributed as pre-finished floors with a wooden surface that is coated with several transparent layers at the factory. The coating can be produced with UV cured polyurethane, oil or wax. Recently, wooden floors have also been produced with a digitally printed pattern that improves the design of the wood grain structure in wood species that do not have sufficient surface quality. e) Ceramic tiles
[0023] Ceramic tiles are one of the largest materials used for floor and wall coverings. The base materials used to form tiles consist of clay minerals, feldspar, and chemical additives required for the molding process. A common method for producing ceramic tiles uses the following production steps. The base materials are ground into powder and mixed. Sometimes water is then added, and the ingredients are wet ground. Water is removed using filter pressing, followed by spray drying as a powder. The resulting powder is then hot pressed under very high pressure (about 40 MPa (400 bar)) to a tile body having a thickness of 6 - 8 mm. The tile body is further dried to remove remaining moisture and stabilize the tile body to a solid homogeneous material. Recently, dry pressing of large and thin panels has been introduced. Dry granular material is pressed at very high pressure up to 40 MPa (400 bar), and panels with a size of 1x2 m and more, and with thicknesses below a few mm, can be produced in a cost efficient manner. Such panels can be used for wall panels and countertops. Production time has been reduced from several days to less than an hour. Such panels can be cut and molded to production tolerances that are superior to traditional methods, and can even be installed in a floating way with mechanical locking systems. One or more layers of enamel, which is a glass-like substance, are applied to the tile body by dry or wet methods. The thickness of the enamelling is about 0.2 - 0.5 mm. There can be two glazes on the tile, first a non-transparent glaze on the tile body, then a clear glaze on the surface. The purpose of tile enamelling is to protect the tile. Enamel is available in many different colors and designs. Some glazes can create different textures. The tile is fired after enameling in a furnace or oven at very high temperatures (1300°C). During firing, the enamel particles cure and melt together, forming a wear-resistant layer. Roller screens are often used to create a decorative pattern. The contact nature of rotary screen printing has many disadvantages, such as breakage and long set-up times. Several tile producers have therefore recently replaced this conventional printing technology with digital inkjet printing technology, which offers several advantages. In general, oil-based inks are used, and the print is applied to the body of the pressed tile, or in a base enamel which is applied in a wet form and dried before printing. A layer of clear enamel can be applied to the fingerprint in order to improve wear resistance. Digital non-contact printing means no breakage, and possibility of using thinner tile bodies. Shorter assembly times, random printing with no repeating effect, and ability to print on surfaces of variable structures, and on tiles with bevelled edges, are other major advantages. Additional circumstances that have contributed to the introduction of digital printing technology in the tile industry is the fact that ceramic tiles are preferably small compared to, for example, laminate and powder-based floors which are produced as large pressed boards of about approx. 2.1 x 2.7 m. Preferably, small printers with a limited number of print heads can be used in the tile industry, and the initial investment is preferably limited. Oil-based paints have a very long drying time, and clogging of nozzles can be avoided. Other advantages are related to enamelling that provides a base color. In general, smaller amounts of pigment are required to form a tile pattern in a base color than to provide an advanced wood grain design on an HDF or paper material used in laminate flooring where impregnation and lamination create additional problems.f ) LVT floors.
[0024] Luxury Vinyl tiles, commonly referred to as LVT floors, are constructed as a layered product. The name is somewhat misleading as most LVT floors are plank size with a wood pattern. The base layer is mainly produced from several individual base layers comprising different mixtures of PVC powder and limestone filler, so as to reduce material costs. The individual base layers are generally about 1 mm thick. The base layer has a thin high quality printed decorative PVC sheet on the top side. A clear vinyl wear layer with a thickness of 0.1 - 0.6 mm is generally applied to the decor sheet. Fiberglass is often used to improve thermal stability. The individual base layers, fiberglass, the decorative sheet, and the transparent layer, are fused together with heat and pressure in continuous or batch presses. The clear layer can include a polyurethane coating, which provides additional wear and stain resistance. Some producers have replaced the clear vinyl layer with a polyurethane layer that is applied directly to the decorative sheet. Recently, new types of LVT flooring have been developed with a base layer thickness of 3 - 6 mm, and with edges comprising mechanical locking systems that allow floating installations. LVT floors offer several advantages over, for example, laminate floors, such as deep engraving, flexibility, dimensional stability, moisture resistance and inferior sound. Digital printing of LVT floors is only at an experimental stage, but would, if introduced, provide greater advantages over conventional printing technology.
[0025] As a summary, it can be mentioned that digital printing is used on various types of floor to create a decoration. However, volumes are still very small, especially in wood and floor laminating applications, mainly due to high ink cost, and high investment cost for industrial printers. The flexibility that digital printing technology provides is limited by the engraving that is fixed and not possible to adapt to variations in the digitally printed decoration. It would be of greater advantage if the cost of ink could be reduced, if more cost efficient printing equipment could be used on an industrial scale, if higher wear resistance could be achieved without separate protective layers, and if variations in etched structures could be formed that correspond to variations in the digitally printed pattern. Definition of Some Terms
[0026] In the text that follows, the visible surface of the installed floor panel is called "front side", while the opposite side of the floor panel, facing the sub floor, is called "rear side".
[0027] By "above" is signified towards the front side, and by "below" towards the rear side. By "vertically" is meant perpendicular to the surface, and by "horizontally" parallel to the surface.
[0028] By "pigments" is meant a very fine powder of solid dye particles.
[0029] By "pigment ink" is meant an ink comprising pigments that are suspended or dispersed through a carrier fluid.
[0030] By "binder" is meant a substance that binds or contributes to bind two particles or materials. A binder can be a liquid, powder-based, thermosetting or thermoplastic resin, and the like. A binder can consist of two components that react when in contact with each other. One of the components can be liquid and the other dry.
[0031] By "matrix" also called "mat" is meant a material that forms a stamped surface structure when the material is pressed against a surface.
[0032] By "Record Stamp" or EIR means that a printed decoration is on record with a stamped structure.
[0033] By "digital inkjet printing" is meant a digitally controlled ejection of fluid drops comprising a dye from a print head onto a surface.
[0034] By "fingerprint" is meant a digitally controlled method for placing dye on a surface.
[0035] By "dye" is meant any material (dye, organic or inorganic pigments, small colored particles of any material, etc.) that can be used to impart a color to a surface, preferably due to absorption or reflection different wavelengths of light.
[0036] By "panel" is meant a molded sheet material with a length and width that is greater than the thickness. This preferably broad definition covers, for example, laminate and wood floors, tile, LVT, sheet molded wood coverings, and furniture components. Known Technique and Problems of It
[0037] The generally known technologies that can be used to provide digital printing and an embossed surface structure are described below. The methods can be used partially or completely in various combinations with preferred embodiments of the invention in order to create a fingerprint or a digital recording in accordance with this description of the invention.
[0038] High definition digital inkjet printers use a non-impact digital printing process. The printer has print heads that "burn" ink drops from the print head to the surface in a very precise way.
[0039] Multi-pass printing, also called scan printing, is a printing method where the print head moves transversely above the surface, often to generate an image. Such printers are slow, but a small print head can generate a very large image.
[0040] Industrial printers are generally based on a Single Pass Printing method, which uses fixed printer heads, with a width corresponding to the width of the printed medium. The printed surface moves under the heads. Such printers have a high capacity, and they are equipped with fixed print heads that are aligned one after the other in the feed direction. In general, each head prints one color. Such printers can be tailored for each application.
[0041] Figure 1a shows a side view of an industrial single-pass digital inkjet printer 35 comprising five digital print heads 30a-e, which are connected with ink tubes 32 to ink containers 31 that are filled. with paint of different colors. The ink heads are connected to digital data cables 33 to a digital control unit 34 which controls the application of the ink drops and the speed of the conveyor 21, which must be able to move the panel under the print heads with high precision. in order to ensure a high quality image comprising multiple colors.
[0042] Figure 1b shows a top view of a wood grain print P provided on a panel surface 2. The surface of a floor panel is often engraved with a basic structure 17 which is the same for several basic decorations. as shown in figure 1c. Advanced floors use a so-called EIR (Recorded in Register) 17 engraving, which is coordinated with the printed pattern P as shown in figure 1d.
[0043] A typical width of an industrial print head is about 6 cm, and any lengths can be printed. 1-2 m wide areas can be printed with digital printers comprising several series of print heads aligned side by side. 166 print heads may be required to provide a 5-color print on a 2 m wide laminate floor panel and the print can be destroyed if only a few nozzles on a print head are blocked by dry ink.
[0044] Number of dots per inch or DPI is used to define the resolution and print quality of a digital press. 300 DPI is generally sufficient for, for example, printing wood grain structures of the same quality currently used in conventional laminate flooring. Industrial printers can print patterns with a resolution of 300 - 600 DPIs, and even more, and with a speed exceeding 60 m/min.
[0045] The print can be a "full print". This means that the visual printed decoration is mainly created by the ink pixels applied to the surface. The color of a layer of powder, or a base color of a paper has, in such an embodiment, in general, a limited effect on the visible pattern or decoration.
[0046] The print can also be a "print in part". The color of another underlying layer is one of the colors that are visible in the final decoration. The area covered by the printed pixels, and the amount of ink that is used, can be reduced, and cost savings can be achieved due to lower ink usage, and increased printability, compared to a full print project. However, a part print is not as flexible as a full print as the base colors are more difficult to change than when a full print is used.
[0047] Printing can be based on the CMYK color principle where white color is provided by the surface. This is a 4-color composite comprising cyan, magenta, yellow and black. Mixing these together will give a color/gamma space, which is relatively small. To increase specific color or full gamut, spot colors can be added. A spot color can be any color. Colors are mixed and controlled by a combination of software and hardware (print engine/print heads). Flexibility can also be increased considerably by adding a white color to the printer.
[0048] New technologies have been developed by CeraLoc Innovation BelgiumBVBA, a subsidiary of Valinge International AB, which makes it possible to inject a digital liquid print into a layer of powder. This new type of "Digital Injection Impression", or DIP, is achieved due to the fact that the impression is produced in a powder which is cured after impression. Ink and printing are embedded in the cured layer, and they are not applied in one layer as when conventional printing methods are used. The print can be positioned in various dimensions horizontally and vertically at different depths. This can be used to create 3D effects when, for example, transparent and preferably bleached wood fibers are used. A two-layer print can also be used to increase wear resistance. No protective layer, eg overlay, is required, which breaks the original design with gray shadings.
[0049] The DIP method can be used on all powder-based materials, which can be cured after printing. However, the DIP method is especially suitable to be used when the powder comprises a mixture of wood fibers, small hard wear resistant particles, and a melamine resin. The surface layer can also comprise thermoplastic material, for example vinyl particles, which are applied in powder form to a surface. This allows the print to be injected into the vinyl powder particles. Improved design and increased wear resistance can be achieved in such materials.
[0050] A suitable print head has to be used in order to obtain high quality and speed printing on powder based layers and other layers as described above. A printer head has several small nozzles that can fire and apply ink droplets in a controlled manner.
[0051] Industrial ink systems are broadly classified as either continuous ink jet (CIJ), or drop on demand (DOD) systems.
[0052] The CIJ continuously ejects drops from the print head. The drops pass through a set of electrodes, which impart a charge to each drop. The charged drops then pass a deflection plate that uses an electrostatic field to select drops that are to be printed, and drops that are to be collected and returned for reuse.
[0053] DOD ejects drops from the print head only when required and all drops are applied to the surface.
[0054] The CIJ is primarily used for product coding and marking. DOD inkjet technology is currently used in many existing industrial inkjet applications where high quality decoration is required.
[0055] A typical size of an ink droplet is about 2-4 picoliters (= 1*10-12 liter or 0.000001 mm3). The size of each droplet can vary depending on the ink type and head type, usually between 1-40 picoliters, and this corresponds to a droplet that has a diameter of about 10 - 30 microns. Smaller droplets enable high resolution images. Some printer heads can fire different droplet sizes, and they are capable of printing in grayscale. Other heads can only fire a fixed droplet size. It is possible to design printheads that can burn larger drops of up to 100-200 picoliters or more.
[0056] Various technologies can be used to fire the drops out of the nozzles.
[0057] Thermal printhead technology, commonly referred to as bubble jet printing, uses print cartridges with a series of tiny chambers, each containing a heater. To eject a droplet from each chamber, a pulse of current is passed through a heating element which causes the ink to rapidly vaporize in the chamber to form a bubble, which causes a large pressure to build, propelling an ink droplet out through. from the mouthpiece, and to the surface. Many consumer inkjet printers use thermal printer heads. Such thermal printers are generally designed to apply water-based inks with a viscosity of 2-5 centipoises (cps).
[0058] Recently, large-scale thermal print heads with a print width of 223 mm, and with a print speed of about 20 m/min or more, have been developed by Memjet. The print head contains ink channels and two series of nozzles per channel. Each individual nozzle structure is about 30 microns across, enabling 800 dpi, with the second series of nozzles for each color slightly offset from the first to deliver 1600 dpi in combination. A Memjet printhead can continuously burn up to 750 million 2-picoliter drops with a drop diameter of 14 microns per second. Printhead cost is less than 10% of costs for conventional Piezo heads with similar capacity. Such thermal printers can apply water-based substances with a viscosity of 0.7 - 1.5 centipoises, which is similar to the viscosity of water (1 centipoise at 20°C). The Memjet printhead comprises a self-cooling system with the heating element in the middle part of the ink chamber. The drops are ejected, new ink flows into the chamber and cools the heating element.
[0059] Thermal technology imposes the limitation that the ink must be heat resistant, usually up to 300°C, because the burning process is based on heat. This makes it very difficult to produce pigment-based multi-color thermal heads. Memjet printheads are designed for dye-based ink, and are therefore not used in the flooring industry, and in industrial applications where high quality pigment-based inks are required.
[0060] Many industrial and commercial inkjet printers, and some consumer printers use piezoelectric printhead technology, which is the major technology used in the flooring industry. A piezoelectric crystal material (commonly called Piezo) in an ink-filled chamber behind each nozzle is used, rather than a heating element. When a voltage is applied, the piezoelectric material changes shape, which generates a pressure pulse in the fluid that forces a droplet of ink from the nozzle. A Piezo printhead configuration may use different basic deformation principles to eject drops from a nozzle. These principles are generally classified into tight, curved, thrust, and shear printhead technologies. A piezoelectric crystal can also be used to create acoustic waves as it vibrates, and to cause ink to break down into droplets at regular intervals. Piezo inkjet allows for a wider range of inks, and higher viscosity than thermal inkjet. The ink generally has a viscosity in the range of 2 -12 centipoise, and is very suitable for applying pigment-based ink. In industrial applications, printheads that can handle high-viscosity inks are often used, as the initial ink viscosity decreases considerably during production when the temperature may rise to 40°C or more, and a low initial viscosity may fall below the minimum level that is required for correct printhead operation.
[0061] Figure 1e shows how the ink drops 56 are ejected according to the curved mode of piezoelectric material. A Piezo printhead 30 comprises sets of very small holes commonly called jets 50 from which droplets 56 of ink 58, with pigments 12, are ejected onto a paper surface.
[0062] Ink 58 flows from an ink container, via an ink inlet 55, into an ink chamber 52. Electric pulses bend a Piezo crystal 51 and membrane 53. This deformation creates a pressure pulse that ejects a droplet of ink 56 from nozzle 54. Different drop sizes can be formed by varying the electrical charge. Nozzles are typically about 10 microns in diameter. Typical drop volumes are in the range of 2 - 5 picoliters producing 57 printed ink dot sizes on a surface in the range of 10 - 20 microns. Each droplet can contain about 20% pigment. The remaining part is a carrier and resins needed to connect the pigments to the surface.
[0063] A digital image contains a grid of a fixed number of series and columns of pixels, which are the smallest individual element in a digital image. The grid is called a grid. Pixels, which represent images like a computer file, are of a uniform size and shape. They don't overlap and they touch adjacent pixels on all sides. Grid images can be created by a variety of input devices, for example a digital camera. All known printers use Raster Image Processing (RIP) software, which takes an image file input, and produces a sorted, color profile bitmap output, which controls the print heads, and provides the data that is needed. to apply a drop of paint to a surface in a predetermined grid pattern R1 - R4 as shown in figure 1e.
[0064] A lot of ink types can be used. The main components are dyes that provide the color, a binder that binds the dyes to the surface, and a liquid carrier that transfers the dye and binder from the print head in small, well-defined drops to a surface with a free application method. contact. Dye is either a dye or a pigment, or a combination of both. The carrier fluid can be water-based or solvent-based. The carrier fluid evaporates and leaves the colorant on the surface. UV-curable inks are similar to solvent-based inks, but the carrier fluid cures when exposed to strong UV light.
[0065] A major problem for all types of inks and print heads is that when the ink evaporates it can dry out and clog the nozzles. Industrial printers can be equipped with an ink circulation system that circulates ink through jets in order to increase the so-called "decap time" which is the amount of time a print head can be left uncovered. and inactive, and still burns the ink drops correctly. A short decap or clogging time can result in permanent nozzle loss, and unwanted lines can form over the entire surface when single-pass printers are used. Especially pigment-based paints comprising polymer binder systems have a tendency to dry out, and it would be a greater advantage if decap time can be increased, and nozzle clogging can be avoided.
[0066] An ink is a dye that is completely dissolved in the carrier fluid, and the ink is a true solution.
[0067] Pigments are very fine powders of dye particles that are suspended or dispersed throughout an entire liquid carrier. Pigment-based inks are usually individually mixed together using color pigments and various chemicals. The pigments used in digital ink are very small, and have an average particle size of about 0.1 micron. The typical size of nozzles is around 10-20 microns, which means that the pigment particles have plenty of room to pass through the nozzle channels in the printhead. The nozzles can also be blocked by the paint itself and pigments that form groups of particles. High quality pigment ink should keep the pigment suspended in the carrier fluid for a long period of time. This is particularly difficult at preferably low viscosities, which are required for good printhead operation. Pigments have a natural tendency to settle and fall into the liquid carrier. In high quality pigment ink, no pigment settling should normally occur. Advanced ink circulation systems are used to avoid such high pigment ink related problems.
[0068] Pigment inks are generally more stable to light, especially when exposed to UV light, and more resistant to discoloration than dye-based inks. They are therefore used in almost all flooring applications. Water-based digital inks comprising color pigments are especially suitable for flooring applications, and can provide a high quality printing method on many different materials.
[0069] Generally, pigments do not adhere to a smooth surface. They are similar to sand particles, and can be easily removed from drier, smoother surfaces. The water-based carrier fluid is therefore generally mixed with small amounts of various other additives to provide special ink and printing properties such as binders that provide pigment adhesion to a surface, dot gain, pH level , drop formation, print head corrosion, fade resistance, etc. The inclusion of resins that serve as a binder in the paint composition limits the possible amount of pigments, since both components increase the paint's viscosity.
[0070] Color pigments as raw materials are preferably cost-competitive especially since preferably large particles of about one micron, but the production of pigment-based inks comprising very small particles and other inks for digital printers, it is very complicated and costly, and this results in a very high cost for the ink which can normally be in the region of around 50 -100 EUR/litre. About 50-100 m2 of floors can be printed with one liter (20-10 g/m2) if a total high quality print is applied, and this gives a printing cost of 1 - 2 EUR/m2. The costs for conventional printed floor surfaces where printing cylinders are used are only 10% of the cost for digitally printed floor surfaces. This means that conventional pigment-based liquid ink-based print scanning is only cost-competitive in small runs when very high production flexibility is required.
[0071] Digital inkjet printers use a non-contact method to apply ink to a surface. Laser printing, however, is based on a contact method where a laser beam projects an image onto an electrically charged rotating drum, often called a photoconductive drum. The dry ink particles, commonly called toner, are then electrostatically trapped by the charged areas of the drum. The ink comprises finely defined spherical particles of dry plastic powder, such as, for example, styrene acrylate copolymer, or polyester resin, which is mixed with carbon black or coloring agents. The particles have a diameter of about 8-10 microns when 600 DPI print resolution is required. Some laser printers even use smaller particles with a diameter of about 5 microns. The thermosetting plastic material acts as a binder. The drum prints the image onto a paper by direct contact and heat, which fuses the ink to the paper by binding the plastic powder to the paper. Color laser printers use the principle of CMYK with colored dry ink, typically cyan, magenta, yellow, and black, which are mixed together to provide a high quality color image.
[0072] Laser technology with the impact method is not used for printing a flat panel surface, such as floor panel surfaces.
[0073] 3D printing is a well-known technology that is used to apply and connect multiple layers of liquid substance, powder, or sheets together to create advanced three-dimensional structures. The technology is mainly used for prototype production of small complex products. Several hundred layers can be applied to each other. Several principles are used to build layered structures. According to a main principle, the powder layers are applied to each other, and some parts are bonded by a liquid UV-cured substance applied by a digital print head to each powder layer. Unbound powder is removed when the entire product structure is formed. Another principle uses a small glue gun that applies several layers of hot liquid plastic material in several layers. 3D printers have very low productivity and building even small objects can take several hours. 3D printers are not used to create flat decorations on a surface where colorants are applied side by side, and where unbound dust must be removed after each application of a coat. The structure of the layers applied to each other will be destroyed if pressing is used to cure the layers.
[0074] Ink-sublimation printers use a long roll of clear film of red, blue, yellow, and gray colored cellophane sheets, which are secured together end-to-end. Embedded in this film of many sheets attached together are solid dyes corresponding to four basic colors cyan, magenta, yellow and black, and each sheet comprises only one color. The "print head" contains thousands of small heating elements that produce varying amounts of heat and the dye is transferred to a coated paper with "sublimation" which means that the dye when heated turns into a gas without first turning into a liquid. Such thermal print heads, hereinafter referred to as heating print heads in order to differentiate such heads against the thermal print heads used in bubble jet printing, heat up as they pass over the film, causing dyes vaporize before they return to solid form on the paper. This method eliminates the use of liquid ink, and can provide high photo quality with dyes that are transparent, and that blend into a continuous hue color. However, the method has many disadvantages. Each sheet must be the same size as the printed surface, and the entire sheet is used even if a small portion of the surface is printed with a specific color. In order to eliminate some of the disadvantages of dye sublimation heat transfer printing, printers have been developed which use special inks comprising sublimation particles. A conventional inkjet press can be used to print an image with such a dye-sublimation ink onto a special paper or sheet. The image is then transferred by pressure and heat to a polyester material, or a surface that has a polymer coating.
[0075] Thermal printing with heating print heads are also used to create fingerprints directly on a heat sensitive paper, or indirectly with a thermal transfer printing method where heat is applied to a heat sensitive transfer film . These printing methods are mainly used for applying a color to a paper, and for printing, for example, labels. Warming printheads have several advantages. They are reliable as there is no risk of ink clogging and the price is competitive in cost. The biggest disadvantages are related to high cost to paper, or film transfer, and color limitations to mainly one color. Warming printheads are available in widths up to 200mm, and can provide resolution up to 600 DPI.
[0076] Print scanning is a very flexible method that can provide high quality printing, but it cannot be fully utilized in industrial application, and especially not on floors due to the high cost for ink, problems related to drying and clogging of nozzles, especially when pigment-based inks are used, and the need for special protective layers that are costly and not completely transparent. The high ink costs are mainly caused by the need to grind the color pigments to very small, well-defined particles, and to disperse the particles throughout the entire carrier fluid. It should be of greater advantage if digital images can be created with color pigments that can be larger, that are not dispersed in a carrier fluid, and that are not applied as drops by small nozzles. It would also be of greater advantage if digital images could be formed with higher wear resistance, and without protective layers.
[0077] Most of all above described floors and especially digitally printed floors have an embossed surface structure, especially when the printed decorative decor is a standard wood. The relief structure was in the past provided as a separate general structure that was used for many different types of decoration. Recently, many flooring manufacturers have introduced the so-called Embossed In Register EIR method where the embossed surface structure is specifically formed for each type of wood species, and the embossing is made in register with the printed decoration. This provides advanced designs that are difficult to differentiate from natural materials such as wood and limestone. Embossing is achieved when the surface is pressed against a structured matrix which can be a plate, belt, metal roll, plastic sheet, or coated paper. The decoration must be positioned with high precision against the pressing matrix. Generally, digital cameras and mechanical devices that adjust the final position of the panel such that it matches the decoration prior to pressing are used to achieve such positioning. A specific problem related to laminate flooring is the fact that printed paper swells and shrinks in an uncontrolled manner during impregnation, and the size of the decoration can vary between sheets of paper that impregnate differently.
[0078] Print digitization flexibility is also limited in conjunction with EIR surfaces, as the printed decoration must always be adapted to the engraved matrix. A common feature for all such floors, as described above, is that all surfaces in a production batch have the same basic structures, and are not possible to adjust and adapt to any changes in decor. This embossed structure repeating effect provides a floor surface that is not limited to a wooden floor where virtually all panels have different designs and structures due to the wood grain structure of the wood. Copies of limestone and other natural materials cannot be produced in a way that is a true copy of the natural material where design and structure are usually perfectly matched, and all panels are different.
[0079] Digital inkjet technology is mainly used to obtain advantages related to the possibility to create high resolution image in a flexible way. However, the other aspects of the technology, mainly related to the possibility of applying a liquid substance very precisely with a non-impact method, have not been fully used or developed, especially not in applications where a decoration is applied to a large-sized panel comprising a surface which during production and especially after printing receives its final shape, and properties in the production steps comprising high pressure and heat.
[0080] It is known that powder applied to a liquid substance can be used to create raised portions or an image on primarily a paper substrate, and that the liquid substance can be digitally applied by inkjet. 3-D printing comprising multiple layers of powders that are locally connected with a digital device, such as an ink head, and where excessive unconnected dust particles are removed in a final step is a well-known technology that can be used to create an embossed structure on a panel. It is also known that powder particles can be applied directly with a non-contact method to a surface comprising a binder, or indirectly with a contact method where a transfer method is used. Even combinations are known where a non-contact transfer method is used, and the powder is detached from the transfer surface with heat or scraping.
[0081] US 3,083,116 describes a high print powder and high print process comprising sweeping a powdered resin after a freshly printed sheet, removing from excess powder that does not adhere to wet ink, and applying of heat to the powder trapped in the sheet to melt it so that particles of it flow through and adhere to the sheet. The powder may comprise a phenolic resin such as phenol, urea and melamine.
[0082] US 3,440,076 describes a method of forming high rigid print characters on a sheet of paper. An ink composition is printed onto the paper and then contacted with a dry material. One of the paint and dry material composition contains a thermosetting resin, and the other material a blowing agent and a curing agent. The dry powder material that does not adhere to the ink is removed, and the resin associated with the printed character is then heat cured at temperatures sufficient to melt the powder.
[0083] US 3,446,184 describes a method for forming an adherent image copy. Toner powder is applied in a liquid formation and a portion of the powder is retained by the liquid coating, forming a visible image. Loose powder is removed, and the sheet passes into a heating unit where the trapped powder is fused to form a permanent image.
[0084] US 4,312,268 describes a method by which water-based ink is digitally applied to a continuous web and simple meltable powder material is applied to a web and into the ink. Some of the powder material is bonded to the liquid, and unbound powder material is removed from the web prior to heating the web to dry the liquid and melt the powder material to the web by melting the powder. It is mentioned that the powder material has a particle size in the range of 5 to 1000 microns, and may have a melting point or melting point in the range of 50 to 300°C. The powder material can be produced by dissolving or dispersing, respectively, a dye or pigment in a resin or resin formulation, followed by grinding, spraying or the like, to reduce the material to a fine powder. The powder material can provide abrasion resistant qualities to paint which may contain phenolic resin. The liquid material, which is applied through the jets, can be clear, colorless water.
[0085] GB 2 128 898 describes a method for forming raised decorative portions on a plastic tile. A decorative floor covering in the form of a tile has a design printed on its upper surface. Particles, such as inorganic sand particles, are positioned on the top surface of a plastic tile with at least some of the particles being placed on the tile surface in registration with the design printed on the tile surface. Excess sand particles are removed. A cured wear layer overlies both the raised particle and the plastic base, so that the surface of the wear layer in areas containing particles and areas not containing particles will have different gloss characteristics. The process requires spraying particles onto an adhesive-coated surface to retain the particles in register with a design printed on the tile surface.
[0086] US 6,387,457 describes a method of using dry pigments for printing applications related to automotive paint, security printing, general paint and cosmetics. A binder material is applied to a surface of a substrate evenly, or in a pattern. The binder is applied by inkjet, spray, sieve, offset printing or gravure. Dry pigment is applied to the binder material in a pattern, or evenly. The dry pigment material comprises flakes of non-metallic material having a particle size less than about 100 microns. The flakes are aligned in a parallel direction with the substrate surface, and a protective coating can be applied to the flakes.
[0087] EP 0 403 264 A2 describes a transfer method for forming a multicolor image on a drum which transfers the image onto a paper. A digital fluid imaging is subsequently developed at a development station where colored powder is applied to the fluent imaging and fixed to produce a visible, permanent image. Various digital print heads can be used that print with dyeless fluids comprising a mixture of water and polyhydric alcohols and their subsets of Ethylene Glycol, Glycerol, Diethylene Glycol and Polyethylene Glycol. A powdered toner is applied across the surface of the paper and a voltage is applied during this development. The voltage is then reversed to remove toner from the background areas. Fixation is achieved through conventional copier fusing methods.
[0088] US 5,627,578 describes a method for producing raised letters and graphics in desk top printing applications by using thermographic powder and an inkjet printer to apply a liquid binder. The method is similar to the methods described above for producing elevated text.
[0089] EP 0 657 309 A1 describes a multicolor transfer method using a transfer paper carrying a pattern formed by ink jet and powder, similar to the methods described above. The transfer method is intended for decorative ceramics.
[0090] WO 2007/096746 relates to systems and apparatus for transferring granular material with a non-contact or contact method to a surface to be decorated, particularly for obtaining decorations on ceramic tiles. A liquid digital pattern is provided by ink jetting onto a transfer surface which can be a drum or a belt. Granular material is applied and bonded to the transfer surface, and only bonded granular material is moved to a transfer zone where heat is applied to a specific portion of the transfer surface in the transfer zone, so as to detach granular material from the transfer surface, and to apply the granular material to the receiving surface. The granules can also be peeled off. The biggest advantage with this method is that only particles that form the final image are applied to the receiving surface. The biggest disadvantage is that heating must be sudden, and particles must be released from the transfer zone, and they fall onto the receiving surface in a very controlled manner in order to obtain a high resolution image. High resolution can only be achieved with preferably heavy particles that fall by gravity onto the receiving surface. The granular material used in the invention is of the type comprising non-porous granules, such as, for example, grains of vitreous materials or sintered mixtures, sand, etc., in the various particle size ranges from 30 µm to 800 µm, preferably ranging from 50 µm to 150 µm. A transfer impression with a contact method is also described.
[0091] WO 2011/107610 describes a method for creating an elevation or relief in a floor panel so as to avoid the use of costly press plates. The method is the same as the known methods for creating a high impression. It describes a method of producing a floorboard by printing a curable substance to create an elevation in the panel. Elevation can be applied in a basic decorative pattern that is directly printed or laminated onto the panel. The curable substance may comprise wear resistant particles. The curable substance can be digitally printed on the panel by first printing a liquid in a predefined pattern and then providing an intermediate substance which can comprise a powder. The curable substance can be cured by UV radiation, or it can be a varnish.
[0092] EP 2 213 476 A1 describes that a predetermined pattern can be digitally printed on a liquid curable carrier so as to form an embossed decoration pattern, which is pressed into the overlay. The curable liquid may be a plastic, which preferably becomes rigid after curing, for example a plastic-containing paint. This method is not suitable for flooring applications. The print scan head can only print a very thin layer with a thickness of about 10-20 microns. Thicknesses of at least 100 - 200 microns that are required to form an engraving on the laminate and 200-700 microns to match the requirement of wood-based floors are not possible to produce in an economical way.
[0093] The document WO 2012007230 describes a method for forming a 3-D structure in a furniture or floor panel with a digitally controllable device. A decoration is applied with a flat three-dimensional structure of powder-based coating material comprising one or more layers, which are locally solidified by a digitally controllable device under the action of light and/or heat radiation. Excess unsolidified coating material is removed in a final production step. The three-dimensional structure can be digitally printed. A liquid coating material is applied to the 3-D structure as a protective layer.
[0094] Most known methods are based on the direct application of powder onto a surface comprising a binder pattern. They are primarily used to create raised text or three-dimensional decorations, which are cured and protected by a liquid coating. Such methods are not suitable for laying floors where colored powder must be incorporated into the surface in order to provide sufficient wear resistance. None of these direct application methods are combined with a pressing step which compresses the applied powder, and especially not with a pressing step which cures the entire surface layer such that the powder particles are fused to the surface.
[0095] Some of the known methods are based on an indirect application of powder with a transfer method. Pressing is only used to transfer the powder from a conveyor, and no pressing steps take place to cure the powder and surface.
[0096] Known methods are not suitable for creating a high quality multicolor image on a building panel, and especially not on a floor panel where UV resistant pigments are to be used, and where the image is to be embedded in a wear resistant surface. It is not known that the principles described above can be used to create a digital image on a panel which after the printing step is cured under high heat and pressure, and especially not how the principles should be adapted for printing floor surfaces similar to laminate and Wood Fiber Flooring (WFF) where the powder, paint and application methods must be tailored to the specific thermosetting resins, wood fiber materials, and pressing parameters that are required to form a high multicolor surface. quality resistant to wear, impact and effort in a cost efficient way.
[0097] The known methods do not provide any solutions to the main problem that is related to the bond between the powder and the liquid binder applied on a surface. In order to remove excessive applied particles, strong air currents must generally be used, and such air currents will even remove particles that must be bound by the binder.
[0098] The above description of various known aspects is the applicant's characterization of such, and it is not an admission that the above description is prior art when the products, methods and equipment described are used partially or completely in various combinations. Objectives and Summary
[0099] The primary objective of at least certain embodiments of the invention is to provide an improved and cost-effective printing method for applying dyes to a surface in well-defined patterns on, preferably, a floor panel surface by the use of print heads. digital ink that can apply a liquid substance to a panel surface.
[00100] A specific objective is to provide an equipment to form fingerprints according to the main objective.
[00101] The above objectives are exemplary, and embodiments of the invention may effect different or additional embodiments.
[00102] Embodiments of the invention are based on a main principle where conventional digital printing methods are divided into two separate steps comprising a separate application of a liquid binder and dry dyes. Colored particles are applied to a panel surface. Some particles are connected by a digitally formed pattern. Other unbound particles are removed, and the remaining bound particles form a digital pattern. The two-step process can be repeated, and multiple colors can be applied such that an advanced multi-color high definition digital print can be formed. The bonded colored particles and the panel surface are pressed together, and an increased bond is obtained. The pressing is produced under increased temperature such that the colored particles and surface are cured to a hard wear resistant layer.
[00103] An advantage compared to conventional inkjet printing is that the colored particles are not dispersed in a liquid substance, and are not applied by a digital print head onto a surface. According to embodiments of the invention, a print head is only used to apply water-based binder that is cost-effective and mostly pigment-free. Embodiments of the invention make it possible to combine lower costs for ink and digital print heads with improved productivity. Pigment based dyes can be combined with very cost effective printheads which can be thermal printheads. The colored particles can be pigment-coated wood fibers or mineral particles, and very realistic copies of wood and stone designs can be obtained with such decorative materials in high quality patterns.
[00104] An advantage compared to known powder-based printing methods is that the colored particles are applied directly to a panel surface. Handling and transporting separate printed sheets, which can cause dust to fall out, can be avoided. The placement of separate surface layers, such as sheets of paper on a panel, can also be avoided, and the digital print can be positioned with high precision in relation to the panel. One advantage is that material composition and surface layer properties, combined with value and pressure, are used to obtain a permanent bond of the colored particles to the surface, and such bonding can be achieved in the same pressing step that is used to cure and laminate the surface layer to the core of the panel. Bonding particles with pressure and heat, and using surface properties to provide a bond, is superior to many other curing methods that are used in known powder-based printing methods. Strong bond strength during application and dust removal can be achieved with the liquid binder that reacts with resins that are included in the surface and powder.
[00105] A specific advantage is that the method is based on a liquid binder that is suitable for combining with heat and pressure, and that it can be a very simple substance comprising Glycol that allows a long decap time. No solvents or UV curing chemicals are required, and this can provide a very environmentally compatible, cost-effective production method.
[00106] A first aspect of the invention is a method of forming a fingerprint on a panel comprising a surface, wherein the method comprises:
[00107] • move the panel under a digital gob application head,
[00108] • apply a liquid binder with the digital drop application head on the surface;
[00109] • apply colorants to the liquid binder and surface;
[00110] • bind a part of the dyes to the surface with the liquid binder;
[00111] • remove unbound dyes from the surface such that a fingerprint is formed by the bound dyes;
[00112] • apply heat and pressure to the panel, surface, and bonded dyes such that the dyes are permanently bonded to the surface.
[00113] The at least one of the surface and the dyes can be compressed by the step of applying heat and pressure on the panel, on the surface, and on the bonded dyes.
[00114] The liquid binder may comprise glycol or glycerin.
[00115] The surface may comprise a material that is curable under heat and pressure.
[00116] The surface may comprise a material that is meltable under heat and pressure.
[00117] The surface may comprise wood fibers.
[00118] Colorants can be pressed on the surface when heat and pressure are applied to the panel.
[00119] The surface may comprise a thermosetting resin that is cured with the step of applying heat and pressure, such that the dyes are permanently bonded to the surface with the cured thermosetting resin.
[00120] The surface can be a part of a building panel.
[00121] The surface can be a part of a floor panel.
[00122] The surface can be a layer of paper, or a sheet.
[00123] The surface may comprise a layer of powder.
[00124] The surface may comprise color other than dyes.
[00125] The liquid binder may comprise water.
[00126] The applied liquid binder may be exposed to IR light, or hot air.
[00127] The digital drop application head can be a Piezo ink head.
[00128] The liquid binder can be applied to the drops arranged in a grid, and in which the dyes are bonded with several drops.
[00129] The liquid binder may comprise 10 - 70% water, and 30 - 90% glycol and/or glycerin, by weight.
[00130] The surface may comprise a dry melamine formaldehyde resin which melts when the liquid binder is applied, and which binds the dyes to the surface.
[00131] Dyes can comprise pigments mixed with a dry binder that interact with the liquid binder.
[00132] The dry binder may comprise a thermosetting resin.
[00133] The dyes can each have a particle body comprising a wood fiber.
[00134] The method may comprise additional steps of applying new dyes with a different color to the first bound and surface dyes, binding a portion of the new dyes to the surface with a binder, and removing new unbound dyes from the surface , such that a fingerprint is formed with the first and new colorants placed side by side on the surface.
[00135] Dyes can be applied by diffusion.
[00136] Digital printing can comprise dyes arranged in a wood grain pattern, or in a limestone pattern.
[00137] Colorants can be applied in the liquid binder.
[00138] The surface with bound dyes can be pressed with a pressure of about 4-6 MPa (40-60 bar), and heated with heat exceeding about 160°C.
[00139] The surface and dyes can be pressed and cured on a hard surface with an embossed structure, such that a portion of the dyes is positioned below the tops of the surface.
[00140] All known equipment for applying powder-based prints uses a flexible sheet, such as paper, as an application surface. Cost efficient equipment, which can be used to provide high quality powder-based printing on a panel by applying dyes in a digitally formed binder pattern, is not known.
[00141] A second aspect of the invention is an apparatus for providing a fingerprint on a panel comprising a surface. The apparatus comprising a conveyor, a digital drop application head, a dry ink application station, and a dry ink removal station, in which the conveyor is adapted to move the panel essentially horizontally under the drop application head digital, in which the digital drop application head is adapted to apply liquid ink blank to the surface, in which the dry ink application station is adapted to apply dry ink comprising dry dyes in the ink blank, to the liquid ink blank is adapted to bind a part of the dyes to the surface, and in which the dry ink removal station is adapted to remove the unbound dyes from the surface after each application of blank ink and dry ink.
[00142] The digital drop application head can be adapted to apply liquid blank ink comprising glycol or glycerin on the surface.
[00143] The equipment may additionally comprise a press, in which the press is adapted to apply heat and pressure to the panel, surface, and bound dyes when unbound dyes have been removed, such that at least one of the surface and the dyes are compressed, and the surface and dyes are bonded together.
[00144] The digital drop application head can be digitally connected to a digital control unit that controls the application of blank ink drops, the conveyor speed, and the function of a dry ink application station.
[00145] The dry ink application station may comprise a roller.
[00146] The dry ink application station may comprise an etched, embossed, etched, sandblasted, or needle-based roller surface, which acts as a dispensing device that is adapted to move a quantity. pre-determined surface dry paint.
[00147] The dry ink removal station can be adapted to remove the colorants by a stream of air.
[00148] The dry ink removal station can be adapted to remove colorants by air currents and vacuum that blows and sucks up the colorants.
[00149] The digital drop application head can be a digital Piezo print head.
[00150] Several digital drop application heads can be positioned side by side such that essentially the entire width of the surface is covered by the heads.
[00151] The equipment may further comprise a stabilization station adapted to provide moisture and heat, to stabilize a powder surface comprising wood fibers and dry melamine resins, and in which stabilization is done before applying the paint in white.
[00152] The digital drop application head can be adapted to apply blank ink comprising water.
[00153] The equipment may further comprise an IR lamp adapted to dry the ink blank after application.
[00154] The dry paint application station and the dry paint removal station can be adapted to apply and remove particles of wood fiber-based dry paint. Brief Description of Drawings
[00155] The invention will now be described in conjunction with preferred embodiments, and in greater detail with reference to the attached exemplary drawings, in which,
[00156] Figures 1a-e illustrate known methods for producing a printed and embossed surface;
[00157] Figures 2a-e illustrate a first principle of an embodiment of the invention;
[00158] Figures 3a-d illustrate a second principle of an embodiment of the invention;
[00159] Figures 4a-d illustrate a third principle of an embodiment of the invention;
[00160] Figures 5a-h illustrate digital application of pigments according to the first principle of an embodiment of the invention;
[00161] Figures 6a-d illustrate production methods based on the first principle of an embodiment of the invention, and a panel with a decorative pattern formed in accordance with an embodiment of the invention;
[00162] Figures 7a-c illustrate application of dyes to a surface;
[00163] Figures 8a-h illustrate preferred embodiments of macro dyes;
[00164] Figures 9a-e Illustrate application and pressing of macro dyes;
[00165] Figures 10a-c illustrate application and pressing of macro dyes;
[00166] Figures 11a-c Illustrate application of various colors with a print head and application and removal of dyes with intermediate pre-press;
[00167] Figures 12a-d illustrate transfer printing methods and panels with preferred surfaces;
[00168] Figures 13a-d illustrate application of dyes in patterns with methods where liquid ink blank is not used to bind dyes;
[00169] Figures 14a-d illustrate digital recording with press particles; and
[00170] Figures 15a-d Illustrate digital recording combined with digital transfer printing. Detailed Description of Achievements
[00171] Figures 2a-2d schematically show an embodiment of the invention, which is based on a first principle where a BP binder pattern or image is digitally formed by an ink head that preferably only applies a binder 11 in a surface 2 as shown in figure 2a.
[00172] Dyes 7, which may comprise small colored particles, eg pigments 12, are randomly applied, preferably in dry form by a second device, such that they are in contact with the binder pattern BP. Figure 2b shows a preferred embodiment where pigments 12 in dry form are diffused over the BP binder pattern. Figure 2c shows that binder 11 binds some pigments 12 which form the same pattern as binder 11, and an imprint P is formed on surface 2 when other unbound pigments 12 are removed from surface 2 by, for example , vacuum.
[00173] This three-step process, hereinafter referred to as "print formation cycle", when the process relates to an application of a color, or "Binder and Powder printing", or BAP printing, when the The process refers to total printing, and where, preferably, a liquid binder 11, hereinafter referred to as a "blank ink", and dry particles comprising dyes 7, hereinafter referred to as "dry ink" 15, are applied separately and bonded together, and where unbound particles are removed, can provide a fingerprint P with the same or even higher quality as conventional print scanning technology.
[00174] The surface 2 can be a layer of paper or a sheet, or a layer of powder.
[00175] Surface 2 can be a part of a building panel, or a floor panel 1.
[00176] The binder may be ink blank 11 comprising a liquid substance which is preferably applied by a digital ink head.
[00177] The liquid substance may be water-based.
The surface 2 with the bound dyes 7 can be heated and pressed.
[00179] The surface 2 and the dyes 7 can be pressed and cured to a hard surface with an embossed structure.
[00180] Dyes 7 can be macrodye particles larger than 20 microns, and they can be pressed onto surface 2.
[00181] Surface 2 can be a part of a panel 1 which can be a laminate, a wood floor, a wood-based floor, a tile, or an LVT floor.
[00182] Liquid blank ink can be replaced with a digital heating process where heat from a digital heating print head or a laser activates a binder included in the dry ink and/or surface.
Blank ink and dry ink can be applied in many alternative ways. Surface 2 can point upwards or downwards, and blank paint and/or dry paint can be applied from above or below. The surface 2 with white paint can, for example, point downwards, and can be brought into contact with a layer of dry paint. Unbound dry paint can be removed by gravity when the surface is separated from the dry paint layer. In order to simplify the description, most preferred embodiments show a surface pointing upwards, and fixed to a panel prior to printing. Separate surfaces 2 without a support panel 1 can be printed in accordance with the principles of the invention.
[00184] The method is particularly suitable in applications where considerable amounts of dyes, preferably pigments, are applied on a large flat panel in order to form an advanced large print, or decorative pattern with preferably high wear, resistance to wear. impact and UV, and where the pattern is preferably intended to copy a wood or limestone design. Such designs are generally formed with a base color which, for example, gives the wood or limestone the basic appearance, and a few dot colors which are used to form the wood grain structure, knots, cracks, and various defects. which are visible in the surface of the wood, or cracks in crystal structures, and other defects in a limestone design. The method is also very suitable for forming a pattern on a tile, or for printing laminate and wood-based floors with a copy of, for example, a tile floor comprising tiles with different cores and grout lines between the tiles.
[00185] Contrary to known methods, the digital ink head, hereinafter referred to as "digital drop application head" 30', is not used to apply any type of conventional ink with color pigments or dyes. This is an advantage, as no costly inks comprising pigment dispersions and binder resins have to be handled by the digital drop application head 30'. The ink blank is preferably an essentially transparent liquid substance which preferably mainly comprises water.
[00186] The ink blank, also called liquid substance, preferably does not comprise pigments.
[00187] A print provided by the ink blank, or liquid substance, may be referred to as a liquid print P. The liquid print may be formed from drops of the ink blank applied to the surface.
[00188] The dyes are preferably attached to the surface in two steps. The first bond is an application bond where the dye binding must be sufficient to keep the dyes bound to the BP binder pattern so as to allow the remaining excess dyes to have been applied to areas outside the binder pattern to be removed.
[00189] The second bond is a permanent bond intended to permanently bond the application-dyes bonded to surface 2.
[00190] The first application bond and the second permanent bond may comprise an intermediate stabilization step where the structure of the bound dyes are modified by, for example, heat and/or pressure, such that a new print formation cycle can be produced. The intermediate stabilization step allows new unbound dyes that are applied to the surface during a second print forming cycle to be easily removed even on the surface parts comprising dyes from the first print forming cycle.
[00191] The first application bond is preferably obtained with a liquid substance, also referred to as paint blank, which preferably mainly comprises distilled water or deionized water.
[00192] The adhesion of water may, in some applications, especially when only one color is applied, binds the dye to the surface with a strength that is sufficient to allow removal of unbound dyes. The production costs for such a liquid substance are extremely low, and clogging of the nozzles when a dry binder can be avoided. Some chemicals can be added, for example glycol or glycerin, which are needed to achieve the viscosity and surface tension of the liquid substance that may be necessary for a correct printhead function. Water-soluble polyethylene glycol (PEG), which is available in many different molecular weights, is especially suitable for modifying water, such that a blank paint with a suitable viscosity that operates, for example, with Piezo heads, can be obtained. Low molecular weight formulations, such as, for example, PEG 400, are especially suitable for use in blank ink and preferably joined with dry ink, or a surface comprising thermosetting resins such as melamine. Water and PEG are compatible with melamine resins, and allow fast and easy curing when heat and preferably also pressure are applied. A preferred non-drying solvent that is compatible with thermosetting resins should be miscible with water, have a boiling point above 100°C, and a melting point lower than the application temperature. Examples of such, but not restricted to, are ethylene glycol, propylene glycol, polyethylene glycol, diethylene glycol, butane diol, and glycerin. Combinations can also be used. In some applications, some other smaller amounts of chemicals may be included in the paint blank, for example wetting agents and other chemicals that are needed to prevent bleeding when paint blank is applied to a surface. Ink blank may also comprise release agents, especially when a direct application of the dyes, hereinafter referred to as "direct BAP printing", as described above, is replaced by a transfer application, hereinafter referred to as "printing of Transfer BAP", where blank ink and dyes are, in a first step, applied to a transfer surface and then pressed against and bonded to the surface. Many such additives are cost effective, and ink blank can have a production cost that is a fraction of the costs for conventional pigment-based inks.
[00193] Many Piezo printheads are designed to operate with a viscosity in the range of 2 to 12 centipoise (cps). The water-based blank ink can easily be adapted to meet all possible viscosity requirements.
[00194] A suitable blank ink that preferably can be used in a low viscosity printhead designed to operate with a viscosity of about 5 cps, such as a Kyocera printhead, can be a solution of water-based glycol comprising, for example, about 75% (weight) Ethylene Glycol, or 55% Diethylene Glycol, or 50% Propylene Glycol, or 38% Polyethylene Glycol PEG 400. A glycerin solution water-based comprising about 40% glycerin can also be used. Deionized water can also be mixed with Glycerin and Glycol. A blank ink suitable for a low viscosity printhead may, for example, comprise about 40% water, 50% Glycerin, and 10% Diethylene Glycol.
[00195] A suitable blank ink that preferably can be used in a high viscosity printhead designed to operate with a viscosity of about 10 - 12 cps, such as a Fujii printhead, can be a solution of water-based glycol comprising, for example, about 95% (weight) Ethylene Glycol, or 75% Diethylene Glycol, or 70% Propylene Glycol, or 50% Polyethylene Glycol PEG 400. A glycerin-based solution of water comprising about 65% glycerin can also be used. Deionized water can also be mixed with Glycerin and Glycol. A blank ink suitable for a high viscosity printhead may, for example, comprise about 30% water, 60% Glycerin, and 10% Diethylene Glycol.
[00196] The water content for blank ink adapted for low and high viscosity Piezo printheads can be further increased if high viscosity glycols are used; for example Polyethylene Glycol with a higher molecular weight than PEG 400. A preferred ink blank which is preferably suitable for Peizo printheads may comprise 0 - 70% water and 30 - 100% Glycol, and/or Glycerin. Even more preferred is a formulation comprising 10 - 70% water and 30 - 90% Glycol, and/or Glycerin. Blank ink that is suitable for thermal bubble jet printheads that are designed for very low viscosities; for example 2-4 cps, may comprise more than 70% water.
[00197] All paint blank formulations may comprise small amounts, about 1%, of wetting agents such as BYK or Surfinol, and chemicals such as Actidice intended for bacterial and fungal control.
[00198] The ink blank is preferably essentially a non-curable liquid substance which is used to obtain the application bond, and to bind the dyes until the final permanent bond preferably occurs with heat and pressure, and with resins that are a part of the substrate material and/or dry ink particles. Such a blank ink will not bind particles when it dries, or when heat is applied.
[00199] The ink blank may comprise special curable binders, preferably water-based acrylic emulsions, which are compatible with water, glycol, or glycerin. The preferable binder content is 5-20%. Acrylic emulsions will bind particles when the water content evaporates and they will create a strong bond under high heat and pressure.
[00200] A high water content of at least 50% gives the advantages that the material cost can be low. The decap time will preferably be short, less than an hour, as the water evaporates. A low water content, combined with a high glycol or glycerin content, will increase the decap time considerably. Blank ink, with a water content below 40%, may have a decap time of several hours. A water content below 20% will give a very long decap time that can exceed 6 hours. It is possible to use blank paint that comprises more than 90% glycol, and this can increase the decap time to several days. Ink blank can be produced without water, and high viscosity printheads can handle ink blank which comprises, for example, 100% Ethylene Glycol.
[00201] An ink circulation system can be avoided in industrial printers when ink blank is used which does not comprise any pigment dispersions or binders, and which is mainly a water-based solution as described above. This will increase the cost of the printing equipment considerably.
[00202] Figure 2e shows the viscosity in cps of aqueous solutions of Propylene Glycol (PG) at temperatures of 20 - 30°C. Wl shows water viscosity. Pgl comprises 50% PG and 50% water. Pg2 comprises 70% PG and 30% water. The viscosity of ink blank adapted for a low viscosity printhead can vary between 4-6 cps within the temperature range of 20-30 °C. The viscosity of ink blank adapted for high-viscosity printheads can range between 8-14 cps, and this can be outside of normal printhead operating conditions. This problem can be solved with printing equipment comprising a temperature control system which is preferably combined with a climate control system which controls humidity. The decap time for water-based blank ink can be increased if the relative humidity around the printheads is above 50%.
[00203] The binder that binds the dyes to the surface may comprise two components. The first binder component can be included in the ink blank. The second binder component can be included in the dry paint, or on the surface, and activated by the blank paint. This makes it possible to use, for example, water, in order to obtain application bonding, stabilizing bonding and permanent bonding. Water can react with a binder that can be included in dyes, or on the surface. The ink blank can, of course, comprise a binder which can provide the same bond as the two components mentioned above.
[00204] Blank paint can be applied to any surface 2, for example, a layer of non-transparent paper, an essentially transparent overlay, a powder layer, a stabilized powder layer, a plywood or wooden sheet, a tile enamel, a plastic sheet, or a base color applied to a sheet-shaped material, preferably comprising wood or polymer material.
[00205] The application of the surface 2 to a sheet-shaped material, such as a panel 1, gives several advantages. Handling and positioning of loose layers that can swell and shrink during application of liquid white paint can be avoided. The dye application bond 7 can be made with a very low bond strength, as the surface 2 is supported by the flat panel, and can be moved horizontally on a conveyor directly onto a fastener where permanent bonding with heat and pressure occurs . Curling, cutting and stacking of paper and sheet surfaces can be avoided. Some surfaces such as uncured powder and tile enamelling cannot be handled without a panel support 1.
[00206] BAP printing on LVT floors can also be done when, for example, individual base layers, preferably including a fiberglass layer, and a decorative plastic sheet with a base color, are fused together to a panel. A clear protective layer can be fused with heat and pressure in BAP printing, and decorative plastic sheet, such that dry ink particles are permanently bonded and fused to the surface. Blank ink can be adapted such that floating of the drops on the smooth plastic sheet is avoided. It is an advantage if the ink blank has a high viscosity, preferably 10 cps, and higher.
[00207] Printing BAP on ceramic tiles is preferably produced when the powder is pressed to a tile body that forms a panel. An enamel with one, preferably, base color is applied to the tile, and a BAP impression is applied to the dry enamel. The BAP print and the tile body are then pressed, and a clear protective enamel is applied to the pressed print. The tile is after enameling fired in a furnace or oven at very high temperatures, such that the dry paint particles cure and melt in the tile body and in the enameling.
[00208] The embodiments described above are based on the main principles that BAP printing is applied to a surface 2 that forms a part of a panel 1 and that also comprises a material composition such that when heat and pressure is applied, the panel , surface and print will be permanently bonded together. Such surfaces may comprise thermosetting resins, preferably melamine formaldehyde resins which are generally used in WFF or paper-based laminate floors, castable and curable mineral materials used in ceramic tiles, or thermoplastic materials used in LVT floors.
[00209] BAP direct and transfer printing can also be used on textile surfaces. Dry ink and ink blank can be specially adapted for various textile surfaces. The binders, viscosity of the dry ink, and the size, or dyes, can be tailored to provide proper binding and removal of the dyes.
[00210] Application to some specific surfaces can be improved by a so-called corona treatment, sometimes also referred to as air plasma. This is a surface modification technique that uses low-temperature corona discharged plasma to yield changes in the properties of a surface. Corona plasma is generated by applying high voltage to sharp electrode tips, which forms plasma at the ends of the sharp tips. Materials such as plastics, glass or paper can be passed through the plasma corona curtain in order to change the surface energy of the material. The surface can also be treated with various types of mineral salts.
[00211] The surface may comprise a first base color, which may be used to create a larger portion of the visible colored surface. Powder-based surfaces, preferably comprising thermosetting resins, can be pre-pressed and formed with a smooth surface that facilitates the application and removal of dyes. Pre-press is preferably produced with pressure and heat, and during a press cycle time that ensures that the melamine resin is at a semi-cured level, and in a B-stage, as described in the introduction.
[00212] The dye comprises, in a preferred embodiment, mainly pigments of color 12 which are diffused as dry powder layer over the wet binder pattern BP, as shown in figure 2b. Pigments can be mixed with other particles, for example melamine 13 powder particles which melt when they are in contact with the liquid binder pattern BP, and which bind the pigments to the surface. The dry unbound pigments and melamine powder 13 can be removed by, for example, a current of air or gravity, and the remaining wet melamine 13 and color pigments 12 form a print P, as shown in figure 2c, which is essentially identical to the BP binder pattern created by the blank ink. The dry paint may have the same material composition as surface layer 2 in a powder-based WFF floor, and may comprise a mixture of wood fibers, a dry formaldehyde melamine resin powder, aluminum oxide particles. , and color pigments.
[00213] Print stabilization can be partially or completely achieved by, for example, exposure to IR, hot air, UV light, microwave, pre-press or the like, or combinations of such methods. The binder, which in this preferred embodiment is water or wet melamine, is preferably stabilized by pre-press which binds the color pigments to the surface 2 by drying the wet melamine, or by melting the melamine particles. Pre-press compresses the surface of the printed pattern P. A second pattern can be printed with blank ink on surface 2, and a second layer of pigment and melamine powder can be applied to the surface and over the first print. This can be repeated and an advanced decoration can be created with multiple colors such that the digital image comprises dyes with different colors positioned horizontally apart on the same plane.
[00214] The ink blank is preferably an essentially transparent liquid substance that does not disturb the color of the bound dyes. Blank ink with the same liquid substance can be used together with dry ink comprising many different dyes, and this allows, for example, that a printhead with the same ink blank can be used to apply several different colors that can be applied in several steps with an intermediate application of a digital pattern formed by blank ink. This allows the number of printheads to be reduced considerably, since a printhead with an ink channel that applies the same ink blank can be used to apply a virtually unlimited number of dry inks with cores, structures, particle sizes, different, etc. The simple ink blank composition makes it possible to use more cost efficient printheads, as no color pigment is burned through the small printhead nozzles.
[00215] The stabilization step may, in some applications, be sufficient to create the permanent bond. Final permanent bonding may also occur when the surface is preferably pressed and cured under heat and pressure, in accordance with the methods that are used to cure a laminate or a powder-based surface comprising a thermosetting resin, or a surface comprising a thermoplastic layer. A clear UV curing varnish which is applied over the colorants and which after application is cured in a UV oven can also be used. This clear coat can be applied in liquid form by rollers, or with digital Piezo heads, and in one or multiple steps with intermediate UV curing. A thermoplastic resin, or thermoplastic particles, can also be used to obtain the first application bond, or the second permanent bond. Paper-based or powder-based overlay comprising aluminum oxide and melamine resins can also be used as protective layers and as a permanent bond.
[00216] The low cost and simple chemical composition of the liquid substance applied by the drop application head makes it possible to preferably use simple fingerprint head technology to apply the liquid binder substance. CIJ (continuous ink jet) can be used, as water is easy to recycle, and collected drops can still be disposed of without any recycling. Cost efficient thermal print heads can be used as water is easy to handle with bubble jet technology. Preferably, simple Piezo heads with high productivity and DOD (drop on demand) systems can be used, which can have a long lifetime, and which require a minimum of maintenance due to the very favorable composition of the liquid substance that will not cause any production disturbance, as there are no pigments and preferably no quick-drying resin that must be handled, which is the case when conventional pigment-based paints are used.
[00217] The binder can comprise a wide variety of thermosetting and thermoplastic materials that can be used as particles or chemicals on the surface, in dry ink, or as dispersions in ink blank applied by the digital drop application head. Most such materials can be produced in dry powder form, or as liquid dispersions. It is preferred that the chemical that provides bonding after drying is included in the surface, or in the dry ink, and that the ink blank is a simple liquid chemical without any resins or other chemicals that, in dry form, can clog the nozzles. .
[00218] As an alternative to thermosetting materials, such as melamine, or to thermoplastic materials, such as, for example, PVC powder, UV-cured polyurethane can, for example, be used in powder form, or as a dispersion.
[00219] UV-curable polyurethane substance with a viscosity that is adapted to the 30' digital drop application head can be used. Water-based polyurethane dispersions are preferred as a liquid substance in the digital drop application head, as they do not cure until they are exposed to UV light. Polyurethane dispersions are completely reacted with polyurethane/polyureas of small, discrete polymer particles, and such particles can be produced with a size of about 0.015,0 microns, and can therefore be handled in a head. fingerprint, or other similar heads. Polyurethane dispersions can be blended with, for example, acrylic and other emulsions in order to reduce costs.
[00220] The digital droplet application head, which in some applications preferably may be a Piezo head, preferably has a capacity to burn droplets with a droplet size of about 1 - 200 picoliters, or more. The droplet size and droplet intensity can be varied, and these can be used to vary the intensity of a color, and create a so-called "gray scale" with the same basic color. Larger drops will bind thicker layers of dry paint, and smaller drops will bind thinner layers.
[00221] Water-based adhesives can also be used, such as soluble adhesives, or water-dispersed adhesives.
[00222] Other UV-cured materials, such as epoxy acrylates, urethane, polyester, polyether, amine-modified acrylic polyether, and various acrylate oligomers, can be used as binders in powder form or as dispersions.
[00223] Blank paint can also be applied to a surface by spray nozzles, or by engraved rollers.
[00224] Figure 2d schematically shows a BAP print station 40 of a binder printing apparatus that can be used to create a fingerprint P on a panel 1 comprising a surface 2, a core 3, and the support layer 4. A blank ink application station 36 comprising a digital drop application head 30', which preferably is a Piezo head, or a thermal print head, applies a BP binder pattern with ink blank 11. Several heads 30' can be positioned side by side to cover the width of the surface being printed. The binder pattern is digitally created in the same way as in conventional print scanning. The colors are separated, and each ink-blank application station 36 mainly applies the same liquid substance or ink-blank that is used to bind a specific color in each press formation cycle. The digital drop application head is connected with a feed tube 32 to a container 31 with blank ink. The digital drop application heads 30' are digitally connected, with preferably data cables 33 or wireless, to a digital control unit 34 which controls drop application, the speed of the conveyor 21, the function of a unit. dry paint application 27, and all other equipment that is used to bind and remove pigments.
[00225] The water-based drops of paint blank 11, which in this embodiment serve as an application binder, should be wet until they pass the dry paint application station 27 which, in this preferred embodiment, is a broadcast station. The dry ink, which, in this preferred embodiment, comprises color pigment dyes 12 mixed with a spray-dried melamine powder resin 13, is diffused into the liquid white ink 11.
[00226] The diffusion equipment comprises a funnel 45 containing dry ink 15, a doctor blade 47 which, together with a roller 46, preferably comprising a roller surface 44 engraved, embossed, etched with strong water, or blasted with sand 44, acts as a dispensing device which moves a predetermined amount of dry ink 15 from the hopper 45 and onto the surface 2. The roller 46 may also have a roller surface 44 comprising small needles. Rotation and oscillation rollers can also be used. A stock removal device which may be a swing or spin brush 48 may also be used in some applications along with one or several swing or swing meshes 49 which can swing or rotate in different directions.
[00227] The doctor blade 47 can be rigid or flexible, and can have an edge that is adapted to the structure of the roller surface. The rotation or oscillation meshes 49 can also be formed such that they diffuse the dry ink 15 in a predefined way, and they can be combined with one of several screens that can be used to screen the particles before they are applied as a layer. The rotation of the roller, the position of the doctor blade, and the speed of the surface that is intended to be covered with the dry ink can be used to control the thickness of the layer.
[00228] Liquid white ink 11 and dry ink with pigments 12 and melted melamine particles 13 are, in this embodiment, heated and stabilized when they are moved under, preferably, a hot IR lamp 23, which is located, preferably after the digital drop application head 30' in the feed direction.
[00229] A dry paint removal station 28, which, in this embodiment, is based on air and vacuum currents, removes pigments 12 and melamine particles 13, which are non-wet and not bound by the BP binder pattern, and a perfect P color printing is provided. The dry ink removal station may be located after the IR lights 23, or between the IR lights and the diffusion station 27. This production step may be repeated, and a second diffusion station 27 comprising another color may apply a second color in a binder pattern that can be applied by the same printhead, or a new printhead that is used in a second print forming cycle. The dried removed pigments and melamine particles can pass through a sieve or a filter, and they can be recycled and reused again and again.
[00230] The panel 1 with the surface 2 is preferably displaced essentially horizontally under the digital drop application head 30', the dry ink application station 27, and the dry ink removal station 28, with one or more conveyors 21. It is obvious that the digital drop application head 30', the dry ink application station 27, and the dry ink removal station 28 can alternatively be moved over a panel 1 during printing of BAP.
[00231] The dry ink may, in addition to pigments and melamine particles, also comprise wear-resistant particles, such as small aluminum oxide particles, and fibers, preferably wood fibers, which preferably can comprise or consist of transparent or semi-transparent bleached fibres. Such dry ink can be used to create a solid print with pigments that are positioned vertically above each other with binders and wear resistant particles above and below the pigments. Small droplets of blank ink can, due to capillarity and the combination of surface tension and adhesion forces, penetrate the dry ink and bind larger amounts of dry ink than a conventional ink application where pigments are applied as small drops. on a surface.
[00232] A preferred embodiment of BAP printing is characterized in that the vertical extent of the dyes exceeds the vertical extent of the blank ink drops. Another preferred embodiment is characterized in that the digitally applied blank ink droplets penetrate downwardly and upwardly from the surface after application. A very wear resistant print can be obtained with a printing method comprising blank ink and dry ink with wear resistant particles preferably incorporated in the dry ink.
[00233] Several layers of prints can be positioned above each other, and these can be used to further increase wear resistance and create 3D decorative effects.
[00234] Static electricity or ultrasound can be used to apply and/or to remove unbound dust particles. Air and vacuum currents that blow and/or suck up particles can preferably be combined with brushes. In general, all wet and dry methods that are used to remove dust can be used separately, or in various combinations to remove the unbound parts of the dry paint. However, dry and non-contact methods are preferred.
[00235] Controlled complete or partial removal of unbound dry ink particles is essential for high quality printing with a predefined decorative image. Advanced removal systems can also be used which only remove dyes, eg color pigments, while an essential part of the clear melamine powder particles can remain on the surface. This can be done by, for example, a two-stage application where a first layer comprises only melamine resin or particles that are applied to the surface before applying the paint blank with the dyes. This first layer is preferably stabilized. It can be sprayed with water and dried by, for example, IR or hot air. This separate binder layer, which preferably comprises melamine, can, in some applications, replace, for example, pre-impregnated paper, which, in some application, can be used as a surface layer 2, and only paper not impregnated with or without a base color can be used as a 2nd surface for the print application cycle.
[00236] The moisture content of the surface layer must be precisely controlled in order to facilitate the removal of unbound dust particles. Moisture content below 8%, or more preferably not exceeding 6%, is preferred. The surface layer 2 can be dried by, for example, IR lamps before applying the ink blank. Special chemicals can be applied to seal the surface 2, or the top of the bonded dyes to create a seal or release layer that can prevent the dyes from sticking to specific parts of the surface layer where no ink is blank. is applied.
[00237] The floor panel 1 generally comprises a lower balance layer 4 of laminate, plastic sheets, coated paper, or similar material. Such a balance layer can also be applied as a dry blend of melamine powder and wood fibers, which are stabilized by moisture and heat before pressing. Pigments can be included in the powder mix to provide a base color. The balance layer can also comprise only melamine powder, or a liquid melamine resin, which is applied directly to the back side of the core 3, and no paper or wood fibers are needed to balance the surface layer. The melamine content in the surface layer is preferably higher than in the balance layer. The rear side of the panel is very suitable for providing specific information to the floor installer or end user. Conventional print scanning or BAP print can be used to create a digital pattern or text on the balance layer. Installation and maintenance instructions, logos, other instructions, illustrations and information may be included and may replace information that is generally applied on the packaging, or in special separate instructions. Digital printing, and especially BAP printing, can be very cost effective, as only one digitally applied color is usually sufficient in addition to a base color. The backing layer can also have a fingerprint that is decorative only.
[00238] Figures 3a - 3d show an embodiment of the invention, which is based on a second principle where dry ink 15, comprising dyes 7 and preferably also a binder, which can be melamine 13, in a first step , is applied to a surface 2. A digital print is then, as a second step, formed by the digital drop application head which applies a standard BP blank ink through the blank ink into the dry ink. A major difference between the first and second principles is the sequence of application of blank paint and dry paint. The ink blank 15 is, according to the first principle, applied in a first step, while according to the second principle, the ink blank 15 is applied in a second step. The first principle is referred to below as "Binder Under Powder" BUP printing, and the second principle is referred to as "Binder Under Powder" BOP printing. BUP and BOP fingerprinting can be either a direct print, or a transfer print, as described above.
[00239] These two principles of BUP and BOP can provide different images with different color intensity. Blank ink drops 11 when applied according to the first principle of BUP, will form ink dots when they collide with the surface, and such ink dots will cover an area much larger than the diameter of the drops. Only a part of the liquid substance from the ink dots will penetrate from the surface and into the dry ink. When blank ink drops are applied according to the second BOP principle, they will first penetrate the dry ink particles which will be bonded together into groups of small particles, and a smaller part of the liquid ink blank drops will reach the surface 2 where the small groups will be connected to the surface. Such an application can be used to prevent bleeding in some application where the surface has an open structure that delivers a liquid substance. It should be mentioned that bleed is not always a disadvantage, as it can be used to create decorative effects. The application of dry ink must be precisely controlled when the BOP principle is used, and the maximum thickness of the dry ink layer must be adapted to the drop size and drop intensity, which the ink blank penetrates through the dry ink layer. and on the surface. The thickness of the dry ink layer should preferably not exceed the maximum penetration level of the dry ink drops.
[00240] The thickness of the dry paint layer can vary considerably when the first BUP principle is used, as unbound particles in excess above the penetration level of the blank paint droplets applied to the surface will automatically be removed, and the substance liquid on top of the dry paint particles, can be dried. The thickness of the dry ink layer can be greater or less than the penetration level of the blank ink drops when the BUP principle is used. This provides the ability to use combinations of white ink drop intensity and dry ink vertical extension to create color variations.
[00241] Both principles have advantages and disadvantages depending on the application.
[00242] The ink blank 11 may, still in this embodiment, comprise water, which when applied, melts, for example, melamine particles 13 mixed with pigments 12, or melamine particles applied under the pigments. The binder binds some pigments that form the same pattern as the BP binder pattern, while other unbound pigments are removed.
[00243] Figure 3a shows dry ink 15 comprising a mixture of melamine powder 13 and pigments 12 diffused on a surface 2. Figure 3b shows a BO pattern of digitally applied blank ink applied on dry ink. Figure 3c shows that unbound pigments and, in this preferred embodiment, also melamine 13 particles, have been removed. Figure 3d shows a BAP printing station 40 comprising a diffusion station 27, a blank ink application station 36, an IR oven 23, and a dry ink removal station 28, based on air flow and vacuum .
[00244] The first and second principles can be combined. Ink blank 11 can be applied before and after applying dry ink 15, and this can be used to bind a thicker layer of dyes, and create a solid print with a large vertical span and high wear resistance. Binder printing equipment may comprise binder printing stations which apply drying and ink blank in accordance with the first and second principle.
[00245] Figures 4a - 4d show embodiments of the invention, which are based on a third principle where the bonding of dry ink 15 is effected with digitally controlled heat that activates a heat sensitive resin, and binds dry ink 15 to a surface 2 such that a fingerprint P is formed when unbound dry ink particles are removed. The dry ink 15 comprising dyes 7, preferably pigments 12, can, in a first step, be applied to a surface 2 as shown in figure 4a. A BP binder pattern or image is then digitally formed by the drying methods, and unbound dyes 7 are then removed as shown in figure 4c. Various methods can be used. Figure 4d shows a laser beam 29 that melts or cures a binder, for example a thermosetting resin or thermoplastic resin 13, which can be mixed with the paint blank, or included on the surface 2. The dry paint can also be electrostatically bound to the surface by the laser beam. A scanned P print created is obtained when unbound or unbound colorants are removed. The laser beam can be used to create a binder pattern with heat, or electrostatically before and/or after applying the dyes in accordance with the first and second principles described above for applying ink blank.
[00246] Figure 4d shows a binder printing station 40 comprising a dry ink application station 27, a laser 29, and a dry ink removal station 28, based on a stream of air and vacuum. The laser 29 can be replaced with heating lamps which can be used to create images comprising, for example, preferably large areas of the same color as in some limestone designs, or base colors in wood grain designs.
[00247] Figure 4d also shows that a heat binding station 26 with heating print heads 80 comprising several small heating elements can be used to create high resolution prints with dry binding methods. The heating printhead 80 can apply direct heat which binds dry ink particles 15, preferably comprising pigments 12, and a heat sensitive resin. The heating printhead 80 can also apply indirect heat by heating a heat transfer sheet 81 which may be in contact with the heating printhead 80 and dry ink particles. The heat transfer sheet 81 may be a copper or aluminum foil, and may comprise small individual elements with high thermal conductivity, for example elements produced from copper or aluminum, which are embedded in a heat insulating carrier that prevents the heat of diffusing between individual elements. Heat transfer sheet 81 can be used to increase printability. A pulse of heat from the heating printhead will heat a portion of the sheet and heat will be maintained as the sheet follows the surface and transfers heat to the dry ink particles.
[00248] Even a conventional laser system based on the impact method described above can be used to apply a fingerprint partially or completely to a building panel, or in combination with the binder printing methods described above.
[00249] All the principles described above can be partially or completely combined, and a production line can comprise several digital binder printing stations, according to the first, second or third principles.
[00250] Figures 5a - 5h schematically show side views of applications with two different cores, according to the first principle of BUP. A first binder or a blank ink dot 11a, which in this embodiment essentially comprises water, is applied by a thermal digital drop applying ink head to a surface 2 which may be a stabilized powder layer, or a paper. , as shown in figure 5a. The jets 50 from the head apply ink drops in white 11 through the nozzles 54 when the heater 59 creates bubbles 60 in the ink chamber 52, such that the ink drops in white 11 form liquid dots 11a when they collide with the surface 2 The digital drop application head can also be a Piezo head, and the water-based ink blank can also comprise a viscosity-increasing substance. The water-based ink blank may comprise glycol or glycerin.
[00251] A first layer of dry ink comprising color pigments 12a and dry particles of a binder, in this preferred embodiment melamine particles 13a, is applied on surface 2 and in liquid spot inks 11a as shown in figure 5b. Melamine 13a particles that are in contact with the moist water-based droplets will melt. A first IR lamp 23a can be used to dry the wet melamine and bond the pigments to the surface, as shown in Figure 5c, and the unbound melamine and pigment particles are then removed such that an image of pigment or decoration 12a which correspond to the applied binder pattern formed by the blank ink drops 11a is obtained as shown in figure 5d. Figures 5e - 5h show that the same application can be repeated with a new application of dry paint comprising pigments 12b having another color and mixed with melamine particles 13b, and a new binder pattern 1lb, such that a two-color image is obtained with two types of dyes or color pigments 12a, 12b bonded to two blank ink patterns 11a, 11b as shown in figure 5h.
[00252] Figure 6a shows an embodiment where the digital BAP printing equipment 40 comprises a digital blank ink application station 36, a dry ink application station 27, drying or curing with IR 23, and a station to dry ink removal vacuum 28. The BAP printing equipment 40 is, in this preferred embodiment, combined with a conventional inkjet printer 35. The BAP printing method can be used in this combination to create the larger part of a digital printing, while some parts of the final print can be created by a conventional inkjet printer. This can reduce the ink cost considerably as, for example, the cost effective BAP method, where no pigment has to be handled by the digital drop application head, can apply, for example, 90% of the pigments that are needed to create a fully printed digital pattern or decor. Wood-based floors are particularly suitable for this combined method. A first base color can be provided by the powder layer 2a. A second core pattern can be applied by BAP printing equipment, and a third color can be applied by conventional print scanning equipment. No stabilization of the second color is required as no additional dry colorant will be applied and removed. This embodiment is characterized in that a three-color image is formed of a base color, preferably included in powder or a layer of paper, dry dyes, and liquid ink. The same type of print heads can be used to apply both blank ink and conventional liquid ink.
[00253] A conventional digital printer can be used to apply blank ink which is used as a binder for dry ink and a conventional liquid ink comprising dyes. One or more ink channels may, for example, be filled with blank ink which has different drying and/or binding properties than other channels comprising conventional pigment-based ink. Blank ink drops can be wet when the pigment-based drops have dried. Blank ink can be used to apply dyes that form the larger parts of a digital print's color.
[00254] Figure 6b shows a binder and powder printing equipment 40 where dry ink 15, comprising, for example, a mixture of pigment 12 and melamine powder 13, is applied by a diffusion station 27 preferably comprising an embossed roller 22; and preferably an oscillating brush 42. Unbound dyes, for example pigments and melamine particles, are removed by a dry ink removal station 28 which recycles the mixture 12, 13, or a blank ink in diffusion station 27. A cloud of pigment/melamine powder may be created by air currents, and only pigments and melamine powder that come in contact with wet binder 11 will be bonded to surface 2.
[00255] Figure 6c is a cross-section of a floor panel 1, and shows that the BAP printing method is especially suitable for applying a digital BAP print on a floor panel with a paper base, or surface to base of powder 2, and with a mechanical locking system comprising a strip 6, with a locking element 8 on one edge which cooperates with a locking groove 14 on an adjacent edge of another panel, for horizontal locking of adjacent edges and a tongue 10 on one edge that cooperates with a tongue groove 9 on another edge, for vertical locking of the panels. Such floor panels have generally advanced embossed wood or limestone decorations that require large amounts of different core pigments, and a decoration that has to be positioned precisely in relation to the embossed structures and panel edges where the locking system mechanic is formed. Generally, the decoration must be adapted to the edge portion of the surface portion that is removed when the locking systems are formed. Figure 6c shows a wood grain pattern with a first surface portion S1 and a second surface portion S2 having different cores. The second surface portion S2 which in this embodiment extends mainly in the length L direction of the floor panel, is applied on a base layer 2 comprising the first surface portion S1.
[00256] Figure 6d shows a dry paint removal station 28, which, in this embodiment, is based on air and vacuum currents that blow and suck particles. One or more vacuum suction profiles 41, with openings covering the entire width of the applied dry paint layer, can be used to remove essentially all unbound dry paint particles 11. One or more air knives 42 which also cover at full width, it can apply an air pressure to the remaining unbound particles, such that they are released from the surface of panel 2, and blown into the vacuum suction profile. The biggest advantage with this combined method is that high air pressure is more efficient, and creates a stronger air stream than vacuum. This method can be used to remove essentially all visible dry paint particles from rough surfaces, such as a stabilized powder surface and rough paper surfaces. Even very small particles, for example small pigments or very small wood fibers, can be removed. A two-step process can be used to recycle dry ink. A first removal is done with a dry ink removal station which only comprises a vacuum suction device, and which removes all very loose particles, which can be about 90% or more of the unbound dry ink particles. Such particles are generally very clean, and can be reused. A second combination of dry paint removal station 28 based on vacuum and air pressure, as shown in figure 6d, can be used to remove the remaining particles that may contain some particles from the powder-based surface 2, or from a precious application of another color. Such particles may not be suitable for recycling.
[00257] All of the methods described above can be partially or completely combined.
[00258] Figures 7a - 7c depict the application and removal of dyes 64 having different sizes, and how a solid print P can be formed by pressing together dry ink particles 11.
[00259] The application and removal of dyes are, in some applications, important for a high quality image. In some other application, it may be an advantage if some colorants are left on the surface, as this can be used to create a more realistic copy of, for example, wood drawings, where the wood surface usually always comprises some small blemishes and color dots that are distributed in a random way. Small particles are also difficult to see and, in many applications, will not disturb the overall impression of the decor, especially if they are not applied in a grid pattern.
[00260] Figure 7a shows that very small particles with a size of 10 - 20 microns and smaller may have a tendency to stick to a surface 2 which, for example, may be an uncoated paper surface comprising wood fibers 61 with a preferably rough fiber structure. Figure 7a also shows a pressed part A and an unpressed part B of a panel surface 2. Blank ink drops are applied in a grid pattern R1 - R4. The unpressed part B shows pigments 12a which after removal of dry ink are bound by ink blank, and other pigments 12b which are not bound by ink blank, but which are still affixed to, for example, paper surface after removal due to friction or static electricity. Pressed part A shows pigments 12c which are permanently bonded to surface 2 by pressure and heat. Pigments 12c which have been applied above each other are pressed to a solid flat print P with overlay pigments. A BAP print provides the possibility of creating a print that corresponds to a practically undefined resolution by using a preferably low resolution, eg 300 DPI, when applying blank ink 11. Such a printed pattern can be practically identical to a wood grain structure in real wood pattern or in real limestone pattern, where patterns are formed from different natural fibers, or crystal structures.
[00261] Figure 7b shows that the adhesion problem can be solved with dry ink comprising dyes 7 that are larger than, for example, conventional pigments 12. The dyes are preferably in the range of 30 - 100 microns . In some applications, colorants up to 300 microns in size or larger may be used, depending on the decor. Such comparatively large macrodye particles 64 can be formed in many different ways. The macro dyes 64 comprise, according to a preferred embodiment, pigments 12 affixed to a particle body 66. The particle body is, in this preferred embodiment, a spray-dried melamine particle 13. Such macro dye particles 64 with a size exceeding 20 microns they are much easier to diffuse and remove than small pigments with a size of a few microns or smaller. A major advantage is that pigments are affixed to various parts of the particle body 66 - at the lower parts 66a and upper parts 66b - as shown in Figure 7c, which is a side view of a macro-dye 64 shown from above in Figure 7b. A dot 57 of a liquid blank ink 11 binds a macro-dye particle 64 comprising a number of pigments 12. Pigments 12 are positioned vertically on top of each other on opposite sides of a particle body 66, and such an embodiment can provide a poor impression. depth with increased color intensity and wear resistance. Another advantage is that a small blank ink dot 57 can be used to bind large amounts of dyes or pigments which, in fact, may have a mass or size that is larger than the mass, and ink dot size blank applied as drops from a 30' digital drop application head. A large amount of pigment or dyes can thereby be bound with preferably small drops of ink blank. For example, one gram of blank ink can bind 1-5 grams of dyes. This is a bigger difference compared to conventional print scanning where the liquid ink generally only comprises 20% pigment, and the ink drop always comprises a smaller amount of dyes than the ink drop itself. Generally, about 5 grams of conventional pigment ink must be applied in order to apply 1 gram of pigment to a surface.
[00262] Figures 8a-8h show preferred embodiments of macrodye particles 64. Such particles may comprise or consist of several individual dye particles 69 which can be connected together to macrodye particles 64 having a specific color. Macrodye particles 64 can also be produced by a combination of various materials and chemicals having a particle body 66 and pigments included in particle body 66, or affixed to the surface of the particle body. Figure 8a shows an embodiment comprising several individual dyes 69, e.g. pigments 12, which are connected together with a binder, and which form a macro-dye particle 64. Such macro-dyes can be produced by mixing, e.g. , pigment 12, with a liquid thermosetting resin, for example melamine. The mixture is dried, ground and sieved into macro dyes comprising groups of pigments of a predetermined size.
[00263] Figure 8b shows a macro-dye particle 64 having a particle body 66 of a spray-dried thermosetting resin or thermoplastic resin, which comprises pigments 12a, 12b in the particle body 66, and on its surface. Pigments can be of different colors. The dye in body 66 can also be an ink. Mixing, for example, a liquid thermosetting resin, for example melamine, with pigments or paints prior to spray drying can be used to produce such particles. The pigment on the surface can also be fixed by mixing the pigments with the spray dried particles. Pigments will stick to the surface of the spray dried particle body. Bond strength can be increased if the mixture is produced under increased humidity or heat, especially when the particle body comprises melamine. Melamine-based particles can be heated to a final stage where the pigments will be firmly attached to the body. The level of cure of melamine particles can be increased, and this will prevent the pigments from bleeding during a pressing and final curing of the printed surface. The macro-dye particles 64 preferably have a diameter of about 30-100 microns, and the pigment content can be 10-50% of the total weight. The resin can be melamine or polyacrylate. A binder can also be added to the mixture in order to increase the bond between the pigments and the particle body.
[00264] Figure 8c shows a macro-dye particle 64 comprising a thermosetting particle body or thermoplastic particle body 66 with color pigment 12 in the particle body 66.
[00265] Figure 8d shows that, for example, macro-dye particles 64 can be mineral particles that comprise natural colors. Sand powder or limestone powder, or various types of minerals derived from, for example, oxygen, silicon, aluminum, iron, magnesium, calcium, sodium, potassium, and glass powder, can be used. A preferred material in some applications that are intended to copy limestone is sand which is a naturally occurring granular material composed of finely divided rock and particulate minerals. The composition and color of sand is highly variable depending on local rock sources and conditions, but the most common types of sand comprise silica (silicon dioxide, or SiCh), usually in the form of quartz.
[00266] A preferred embodiment is aluminum oxide 63 which is very suitable for bonding and coating with a melamine resin.
[00267] Mineral particles and especially colored glass particles comprising pigments, similar to the enameling powder used in tile production, are very suitable for printing BAP on tiles, but can also be used in other BAP applications. A BAP impression can be applied to a tile body comprising a base glaze layer with a base color. Such base enamel layer can be pre-pressed or applied in a wet and dry form. BAP printing may, during tile firing, melt into the base enamelling layer. A layer of clear enamel can also be applied over the BAP print. A binder can be applied to the base enamel layer, colored glass particles, or dry paint, such that an application bond can be achieved by exposing the blank paint and dry paint to, for example, IR light or hot air .
[00268] Figure 8e shows that essentially all minerals, such as for example aluminum oxide particles 63, can be coated with a thermoplastic resin or thermosetting resin, for example melamine 13. The resin can be used for bonding pigments of color 12 to particle body 66. Such macro dyes 64 are very easy to apply to and remove from a surface, and they can provide a very wear resistant print with pigments applied to the tops, and bottoms of the surface. particle body 66. A preferred average size of mineral-based macro dyes is about 100 microns. This particle size can be used to create a wear resistant print with a particle depth of 100 microns. The binder content is preferably 10 - 30%, and the pigment content is preferably 5 - 25% of the total weight of the macro-dye particle.
[00269] Mineral particles comprising a pigment-coated aluminum oxide particle body 66 and a melamine resin, are especially suitable to be used as dry ink when a bond is made with a heating printhead 80. The particles of aluminum oxide which have a high thermal conductivity and melamine resin can be bonded with a heat of about 100 degrees C.
[00270] Figure 8f shows that the macro-dye particles 64 may comprise natural fibres, eg wood fibers 61. No pigment is needed as the fibers may have natural colors. Fibers from a lot of different wood species can be used, for example softwood such as pine and fir, and hardwood such as ash, beech, birch and oak. Colors can be modified by heat treatment. Even cork particles can be used. Such natural dyes can be coated with a binder, preferably a thermoplastic resin, or thermosetting resin, for example melamine. The coating can be used to improve diffusion properties and/or as a binder, to bind the macro-dye to the surface, and the binder pattern created by the ink blank.
[00271] Figures 8g and 8h show macro-dye particles 64 comprising wood fibers 61 and wood chips 62 that have been coated with a resin and pigments 12.
[00272] Fiber-based macro dyes can be used to create an almost identical copy of wood. Wood fibers having different colors form the wood grain pattern on real wood plank. The BAP printing method allows the same principles to be used with different fibers that actually form the wood grain pattern, not small ink drops arranged in a grid pattern. This is shown in figure 6c. The panel 1 has a surface with a wood grain decoration comprising a first surface portion SI which is formed by a base layer 2 comprising wood fibers 61a having a first color. A second surface portion S2 is formed from wood fibers 61b having a second color. Wood fibers having the second color are applied on and bonded to the base layer. The base layer is preferably continuous. The second surface portion S2 preferably covers a part of the first surface portion S1. Basecoat 2 can be powder blended with a thermosetting resin, a colored paper, or a colored wood-based core. The fibers on the two surface portions S1, S2 are preferably of different average sizes. The fibers in the second surface portion S2 are preferably smaller than the fibers in the first surface portion S1. The second portion of surfaces S2 preferably comprises a pattern with a length L that exceeds the width W.
[00273] Coating with resins can be used to bind pigments to the particle body, and bind the macro-dye particle by paint blank to the surface. The coating can be produced in several steps with intermediate drying and curing of the resin. It is preferred that a first coating, drying and curing with a thermosetting resin, for example a melamine resin, is produced at a higher temperature than the second cure. The first cure can be produced such that the melamine resin is cured to essentially stage C where the melamine will not float during the final pressing operation, and this will eliminate bleeding of the pigments. The second coat is preferably cured to a B stage, where the melamine is meltable with the dry paint. Dry paint particles can be produced from wood fibers 61 which are mixed with pigments and melamine resin, and they are then pressed under increased temperature such that the melamine resin cures. The pressed mixture can be milled into small particles and coated with liquid melamine resin and dried such that the outer melamine coating is in a B stage. A binder layer can be applied between the pigments and the particle body, and on the pigments , such that they are completely coated with a layer of binder. Several layers of pigments with different colors can be bonded to a particle body of a macro-dye.
The dry ink can comprise a mixture of several different types of macro-dye particles, eg melamine/minerals, melamine/fibers, fibers/minerals etc., and the structure and size of the macro-dyes can be used to create special decorations.
[00275] The coating of the particle body 66 is preferably produced in several steps where, for example, particles such as fibers or minerals, in a first step, are mixed with a resin, preferably spray-dried melamine , and pigments. The mixture can be applied as a preferably thin layer, with a thickness of, for example, 1-3 mm, on a conveyor. The mixture is, as a third step, sprayed with water, and dried by hot air or an IR lamp. The particle body, in this embodiment, the fibers or minerals, are coated and impregnated with the wet melamine, and the pigments are bonded to the particle body. The thin layer makes it possible to dry the layer for a short drying time, for example one minute, and the resin can still be in semi-cured B stage. The dry mixture is removed from the conveyor by, for example, scraping, and the dry flakes are ground and sieved to predefined particle sizes. The spray-dried and water-dried melamine particles can be replaced with a wet binder, for example, wet melamine, which can be sprayed into a mixture comprising pigments and particles that form the particle body 66.
[00276] Pigments can also be bonded to particle body 66 with a binder comprising water-based acrylic emulsions.
[00277] Macro dyes can provide an impression that is very similar to an original wood design or limestone design especially when fibers are used to copy a wood grain pattern, and minerals are used to copy a limestone design. Conventional gravure printing methods with an impression cylinder can be used to apply blank ink to a surface. Dry ink comprising macro-dye particles can be applied to the ink blank, and unbound particles can be removed in accordance with the BAP printing principles described above. Such a printing method can be used to provide an advanced print comprising a design that is not possible to create with conventional ink.
[00278] Macro dyes can be used to create a pattern, preferably a wood pattern or limestone pattern on LVT floors. The BAP printing method can be used to apply an impression to the core, the sheet, or the underside or the upper side of the clear protective layer. Dyes can be melted into the layers during the pressing operation. Prints on different layers located vertically above each other can create a 3D effect. Printing on the transparent layer can create an even more realistic 3D effect.
[00279] Figures 9a-9e show BAP printing with dry ink comprising macro dyes 64 with a fiber-based particle body 66 coated with a melamine resin 13 and pigments 12. Jets 50 of one, preferably, thermal ink head applies white ink drops 11 in a grid pattern R1 - R4 which form white ink dots 57 on a surface 2 which, in this embodiment, is a pre-pressed powder layer applied on a core 3, as shown in figure 9a.
[00280] Figure 9b shows a dry paint layer 15 comprising fiber-based macro-dyes 64 applied to surface 2, and Figure 9c shows the dry paint layer when unbound macro-dye particles have been removed. The ink blank 11 penetrates the dry ink layer 15 from the surface and upwards, due to capillary action, and the properties of the binder and various macro-dyes located vertically above each other can be connected by ink blank dots 57 The horizontal extent H2 of individual dyes, preferably macro-dye particles 64, preferably exceeds the horizontal extent HI of the ink dots 57, and the vertical extent V2 of the dry ink layer, after removal of the particles unbonded, preferably exceeds the vertical extent VI of the ink blank dots 57. The vertical extent VI of the ink blank dots is generally about 10 microns, or smaller. The vertical extent V2 of the applied and bonded paint blank layer, after removal of unbound particles, can be at least 50 microns, or even greater, preferably greater than 100 microns. This is a bigger difference compared to traditional inkjet printing where pigments are included in the ink drops. BAP printing allows a print comprising large volumes of dyes to be formed than the volume of blank ink applied by the digital drop application head.
[00281] Figure 9d shows the printing of BAP P after a stabilization step which, in this embodiment, is a pre-press operation. The macro-dyes 64 can be partially pressed into the powder-based surface 2.
[00282] Figure 9e shows the powder-based surface in a fully cured stage after the final pressing operation. The macro-dyes 64 are pressed onto the powder-based surface 2. The print P comprises pigment 12a, which are located in a horizontal first plane Hpl on top of surface 2a, and pigments 12b located in a horizontal second plane Hp2 below the particle body 66, and below the first horizontal plane Hpl. Macro dyes 64 comprise pigments 12a, 12b on the upper and lower side of particle body 66.
[00283] The macro-dye particles are applied randomly, and are preferably spaced apart from the grid pattern R1 - R4 where each series and column represent a pixel and a dry ink dot 57. Print P can be a solid print with multiple macro-dyes connected to each other, and/or overlapping each other. BAP printing in this preferred embodiment is characterized in that ink blank 11 is applied in a grid pattern (R1 -R4), and that dry ink 15 is randomly applied with overlay dyes 7 or macro dyes 64. Preferably, the size of a macrodye particle 64 is such that it covers several pixels in a grid pattern.
[00284] The thickness (diameter) of the fibers 61 is preferably about 10-50 microns, and the length can be 50 - 150 microns. The length can, in some applications, also exceed 150 microns, and realistic wood grain designs can be formed with fibers having a length of about 100 - 300 microns.
[00285] Figures 10a - 10c show a BAP print with a very high wear resistance. Macro dyes 64a comprising a particle body 66 of aluminum oxide particles 63 coated with pigments 12a and a melamine resin 13, are applied to a surface, which, in this embodiment, is a powder-based surface 2a comprising melamine powder and pigments and preferably also wood fibres. The surface preferably includes a base color. The layer comprising macro-dyes that give the panel a basic color can also from surface 2a, and can be applied directly to a wood or plastic-based core, a tile body, or to a surface comprising powder, paper, a sheet. , and similar surfaces. Figure 10a shows macro dyes 64a bonded to surface 2a by ink blank 11. Figure 10b shows a second layer of macro dyes 64b comprising pigment 12b of a different color.
[00286] Figure 10c shows the final surface cured with macro-dyes that are pressed onto the powder-based surface 2a and preferably covered with a transparent layer, preferably a melamine layer 2b that can be applied after a pre-press operation, but prior to the final pressing step. The transparent melamine layer 2b may also comprise bleached transparent wood fibers. It can be an overlay, a varnish, a foil, or an enamel. A high wear resistance can be achieved, since a considerable part of the surface 2a, 2b, including the particle body 66 of aluminum oxide particles 63, must be abraded before all the pigments 12a, 12b in the print P are removed . Aluminum oxide particles with or without pigments (not shown) are preferably also included in the powder-based surface layer 2a, and/or in the transparent melamine layer 2b. The method can also be used to apply a wear-resistant fingerprint to many other surfaces, such as paper, sheets, tiles, and other surface layers described in this disclosure.
[00287] Figure 11a shows a BPA apparatus comprising several BAP print stations 40a, 40b which each is used for a print forming cycle that applies a specific color. Each BAP station comprises a digital drop application head 30'a, 30'b and a combined dry ink removal and application station 27a, 28a, 27b, 28b, and pre-press units 37a, 37b, which stabilize the ink. 15 such that a fresh coat of dry paint can be applied and removed in accordance with the above principles. A unit embodiment can replace an IR lamp. One embodiment of unit 37a preferably comprises a heating roller 38c and a cooling roller 38d, a belt 20, and a pre-press table 39. These parts may, in some applications, be replaced by just one roller. A liquid release agent 19 can be applied to the belt 20 by rollers 38a, 38b or brushes, or similar devices. Preferably, the drop application heads 30a', 30b' use the same ink blank 11 to provide a multicolor print P. This is a bigger advantage compared to conventional printing. The BAP printing method actually allows the final printing ink to be mixed and produced in-line when the ink blank 11 and the dyes 7 from the dry ink 15 are fixed together on the surface 2.
[00288] Figure 11b schematically shows a compact BAP print station 40, where, for example, a set of digital drop application heads 30' aligned in a series, each comprising an ink channel, and a set of IR lamps 23, or pre-press units, can be combined with several dry ink application stations 27a, 27b, 27c 15 positioned in the feed direction after the drop application head 30'. A series of 30' drop application heads can apply dyes with many different colors. The ink blank, which preferably is an essentially transparent liquid substance, preferably comprises a different color than a first and preferably also a second digital pattern, formed by the drop application head 30 '. This is a bigger difference compared to conventional print scanning, where each print head applies a specific color, and this color is always the same as the liquid substance applied by the print head. A surface layer 2, or a surface that is a part of a floor panel 1, can be shifted in two directions, and each cycle can be used to apply a specific color with the same drop application head. The BAP printing station can comprise IR lamps, or pre-press units, and dry ink application stations, on both sides of the digital drop application head, and different colors can be applied when the surface 2 is displaced under the head 30' in each direction. This means, for example, that three colors can be applied by the same drop application head 30' in a base color when a panel 1 is moved under the head 30', back again to its initial position and under the head again. Speed may vary between different application steps. This can be used to increase capacity. A wood grain pattern is usually composed of different amounts of specific colorants. Speed can be increased when the amount of a specific colorant is low, as only a small amount of blank ink has to be applied to the surface. A digital control system can be used to optimize capacity, and to adapt the speed to the amount of ink blank 11 that is needed to form a specific digital pattern. Various alternatives can be used to combine a blank ink drop application head with multiple dry ink application stations and removal stations. A panel can, after the first print formation cycle, be moved vertically or laterally to a conveyor that brings it to an initial position. An intermediate stacking unit can also be used. Rolled paper and sheet material can be printed multiple times with the same drop application head and the same ink blank.
[00289] Figure 11e shows the pre-press unit 37 that can be used to pre-press a layer of powder with a base color before printing BAP. Such a pre-press unit can also be used to stabilize prints, or to pre-press and attach a backing layer to the powder base 4 on the back side of a core 3. When melamine is used as a binder, a heating roller 38c and a pre-press table 39 can apply a heat of, for example, 90 - 120°C, and a cooling roller 38d can cool the semi-cured layer 2 to a temperature, preferably below 80°C. The pressing can be done at preferably low pressures, for example (0.5 MPa (5 bar)), or lower, and the pressing time can be about 10 seconds or shorter. The melamine will be pre-pressed to a semi-cured B stage which can be further pressed and cured in a final pressing operation. A sheet material with a pre-pressed powder-based surface and backing layer can be produced and used as a pre-finished board. Other binders, for example thermoplastic binders, can be pre-pressed at other temperatures specifically adapted to the properties of the binder.
[00290] Figure 12a shows that a BAP print station 40 and a pre-press unit 37 can be combined into a BAP transfer print station 41, and used in combination to create a BAP transfer P print digital on a surface 2. Blank ink 11 and dry ink comprising dyes 7, preferably pigments 12, are applied to a transfer surface 18 which may be, for example, a plastic belt or belt, or the like. The print P is pressed onto a surface 2 by rollers 38c, 38d and preferably by a pre-press table 38. The BAP transfer printing unit may comprise a cleaning device 71, rollers 38a, 38b, or brushes, which apply a release agent 19, and preferably also an IR lamp 23 which dries the release agent before applying the paint blank 11. The release agent can also be mixed into the dry paint 15.
[00291] The BAP transfer printing method provides the advantages that ink blank and dry ink can be applied to a pre-set transfer surface 18 which can be specially adapted for a high definition ink blank application without any bleed scratches and any easy application and removal of dry paint. This allows, for example, that a BAP print can easily be applied to preferably rough surfaces, such as, for example, textiles, carpets, various board materials, and similar surfaces. BAP transfer printing can be combined with all the other methods described, for example the method described in Fig. 1b where a drop application head 30' is used to apply various colors.
[00292] Figure 12b shows a BAP transfer printing station 41 where the belt has been replaced by a roller 38 comprising a transfer surface 18. The roller preferably comprises heating zones 25a and cooling 25b. Unbound dry ink can be removed by gravity which can be combined with ultrasound, vibrations or drafts. This method can also be used to apply a direct BAP print to a flexible surface 2a which can be paper, sheet, or the like. Application can be done in-line with a pressing operation, or as a separate production step.
[00293] Figure 12c shows a preferred embodiment of a floor panel 1 according to the invention. The panel 1 comprises a support layer 4 on the back side of the core 3, and a surface 2 on the top of the core comprising a sublayer 2c, a paper, or sheet 2b, and a wear layer 2a on the paper. The backing layer 4 and the sublayer 2c can be applied as dry melamine formaldehyde powder, and the wear layer can be applied as a dry melamine formaldehyde powder comprising aluminum oxide particles. The paper can comprise a base color. A BAP print, or a conventional digital print can be applied to the paper. Such a drying process can be used to form a very cost efficient panel without any impregnation of a decorative paper, or a protective overlay. The spray dried melamine particles will melt during pressing, and impregnate the paper. It is obvious that this drying method can be used to save costs even when conventional decorative paper is used.
[00294] Figure 12d shows a method for forming a base layer on rough core materials 3 comprising cavities, crevices, splints, or defects 3a, 3b. Such core material can be produced from, for example, plywood or OSB. The problem is that a layer of powder is generally the same thickness in the cavities and the tops of the core surface, and there will not be enough powder to form a high quality surface after pressing, as the density of the surface layer will be lower on portions of surface with cavities. This problem can be solved with a first powder layer 2a which is applied as a filler and pressed by, for example, a roller or a ruler into the cavities, such that an essentially flat powder-based surface layer 2a is formed. A second powder-based layer 2b can be applied to the first filler layer 2a. The two layers can be pre-pressed, as described above, and a base layer can be formed which, in a second step, can be printed with one, preferably, BAP printing and then cured by heat and pressure. The method can also be used without a print, and only powder layers comprising fibers, binders and preferably pigments can be used. This embodiment is characterized in that the powder content above the cavities is higher than the powder content above the upper parts of the core. Dust content can be measured by measuring the weight of the powder above a cavity and above the top of the surface. The base layer comprising a first filler layer 2a and the second powder layer 2b can be covered with a conventional decorative paper, and also preferably with a protective layer, for example a conventional overlay, or a transparent varnish. .
[00295] Figure 13a shows that a conventional laser printing technology that uses electrical charges to attract and release dry ink particles can be adapted such that fingerprints can be provided on a core material 3 comprising a surface 2 that , preferably has a base color. The negatively charged dry ink particles 15, which may be conventional laser toner pigments, are applied by a developer roller 72 to a photoconductive drum 70, which is in contact with a charge roller 71. A laser beam 29 projects a image on the electrically charged photoreducer drum 70, and discharges the areas that are negatively charged, and an electrostatic image is created. Dry paint particles are electrostatically trapped by the drum's discharge areas. The drum prints the impression P on surface 2 by direct contact. An electrical charge can be applied to the surface, or to the core, such that pigments are released from the drum, and applied to the surface. A fusing roller 73 fuses the dry ink particles to the surface and binds the dry ink particles together. A roller cleaning device 74 can be used to clean the photoconductive drum. The dry paint particles can comprise a thermoplastic resin or a thermosetting resin, which can be used to bond the particles to the surface with heat and pressure.
[00296] Figure 13b shows that laser printing technology can be used to apply a transfer print P on a surface 2. The dry ink particles are applied on a belt 20 comprising a transfer surface 18, and released to starting from the photoconductive drum 70 by an electric application roller 75 which applies an electric rod to the belt 20. The dry paint particles are then melted by a pre-press table 39 which applies heat and pressure to the belt 20 and the transfer surface 15. Heating rollers 38c and 38d can be used. The belt can be replaced with a transfer roller as shown in figure 12b.
[00297] Figure 13c schematically shows several other preferred principles that can be used to apply particles in well-defined patterns to a surface 2 without a digital drop application head that applies a liquid blank ink binder.
[00298] A first principle is a method to create a base layer comprising at least two different colors. A first layer 2a with a first base color is provided as a powder or as a colored paper. A second color of dry ink 15 is diffused into the first base color. Some parts of the dry ink particles 15 are removed with a dry ink removal station 28 comprising a plurality of air nozzles 77a, 77b which can remove dry ink particles by, for example, vacuum before they reach the surface with the base color 2a . Air nozzles 77a, 77b can be digitally controlled with preferably several valves, and a pattern P of dry ink can be formed. This can be repeated, and various color patterns can be formed without any digital drop application heads, or blank ink. This method is particularly suitable for forming patterns that partially or completely can be used to copy wood designs or limestone designs. This method can be combined with BAP digital printing, or conventional print scanning. The method can also be used to create high resolution fingerprints. The dry ink can comprise particles with high density, such as minerals, especially aluminum oxide particles or glass particles, which during diffusion can fall in an essentially predetermined straight direction towards the surface 2, and an accurate partial removal can be done with a vacuum when passing through the air nozzles 77a, 77b. The applied dry paint is preferably stabilized by spraying water before or after application.
[00299] The dry paint particles can, according to a second principle, pass through a set of electrodes, which impart a charge on some particles. Charged particles can then pass a deflection plate 79, which uses an electrostatic field to select particles that are to be applied to the surface, and particles to be collected and returned for reuse by the dry paint application system.
[00300] According to a third principle, a heating printhead 80 comprising small heating elements that produce varying amounts of heat similar to the printheads used in dye-sublimation or thermal printing technologies, can be used to fix dyes to a surface. Several heating print heads 80 can be attached side by side such that they cover the entire width of a printed surface. Temperatures preferably as low as about 100 degrees C can be used to obtain an application bond of the dry paint particles. The heat may also preferably be high, for example 200 - 250°C, and such heat will not destroy wood fibers in paper and powder-based layers. Various methods can be used to form a dry ink digital print where dry ink particles are bonded to a surface on a predetermined digital print. Contrary to known technology, such as heating heads, combined with dry ink, it can be used to apply a wide range of different colors without any heat sensitive papers or transfer sheets. A thermosensitive binder, which can be a thermosetting resin or thermoplastic resin, wax, and similar materials with low melting points, can be included in the surface layer, or in dry ink dyes. Powder comprising dye-sublimation particles of different colors can be used as dry ink. The heating printhead 80 can apply digitally controlled heat directly to well-defined portions of the dry ink after application, or to the surface layer before the application of dry ink. The heating ink head may comprise heating elements disposed on an essentially flat surface, or on a cylinder that rotates when a dry ink surface is moved under the heating print head. Alternatively, a heat transfer sheet 81, as shown in Figure 4d, can be applied between the dry ink and the heating printhead 80, and can slide against the heating elements and ceramic substrate of the printhead. of heating. Unbound dyes or unsprayed dyes can be removed and reused.
[00301] Figure 12a shows that a heating print head 80 can be used to provide heat on a transfer surface 18 which heats the dry ink 15. The transfer surface can be used as a heat transfer sheet 81. The heating printhead 80 may be located such that it provides heat through a transfer surface 18, or in dry ink 15 applied to the transfer surface 18. The heating printhead 80 may also heat the portions. of a surface before applying dry paint. The surface can be a board material, powder, paper, a sheet, a basecoat, a transfer surface, and all other surface materials described in this disclosure.
[00302] Figure 13d shows that the heating print heads 80 and dry ink 15 are especially suitable for being used to form a digital print P on flexible thin surfaces 2 which preferably can be a paper, a sheet, a textile material, and similar materials, which generally have sufficient heat transfer capabilities and heat resistance to function as a heat transfer sheet 81. A powder and heat printing equipment may comprise a diffusion station 27 which applies ink onto white 12 on one surface, a heating printhead 80 which binds a portion of blank ink 15 with heat to surface 2, and a dry ink removal station 28 which removes unbound dry ink 15. In some application, a pre-press unit 37, applies vacuum to the underside of the surface, or oscillation can be used to increase the contact between dry paint particles and surface during heat bonding. to. A separate heat transfer sheet, as shown in figure 4d, can be used to increase printability. The pre-press unit 37 may also comprise heating print heads, and heat may be applied from the top side and/or the bottom side.
[00303] The heating print head 80, with or without a heat transfer sheet 81, can replace all digital drop application heads 30' in the embodiments of this disclosure.
[00304] The embodiments of the three principles described above are based on the main method that dyes are applied as powder in dry form to a surface, and bonded in a predetermined pattern that forms a print. The surface can be a transfer surface 18, and the three principles can be used to provide a transfer impression.
[00305] Figures 14a - 14d show a method for forming a digital recording on a surface 2, preferably an EIR structure, hereinafter referred to as BAP recording. A digital drop application head applies a blank ink pattern onto a conveyor 68, as shown in Figure 14a.
[00306] Press particles 67 which are similar to the dyes shown in figures 8d - 8h can be applied to conveyor 68, which may be aluminum foil, plastic sheet, paper, and the like. The application can be the same as for BAP printing, and all of the methods described above can be used to apply press particles 67 in a pattern onto a conveyor 68. However, the press particles 67 do not have to be coated with pigments. They can be coated with a thermosetting resin 13 or thermoplastic resin. In some application, ink blank is sufficient to provide an application bond. A heating printhead can also be used to bond the press particles 67 to the conveyor. Carrier 68 and/or ink blank may also comprise a binder. The particles are preferably hard minerals such as aluminum oxide, sand, limestone powder, and the like. Such particles that essentially maintain their original shape during pressing and are not compressed during a pressing operation are referred to as hard press particles. Particle size must be adapted to the depth of the recording. Particles with a diameter of about 0.2 mm can, for example, be used to create an engraving having a depth of at least 0.2 mm. The conveyor 68 with the press particles 67 is positioned and coordinated with a printed pattern P which can be a conventional print or a BAP print applied on, for example, a powder or paper surface 2. Figure 14b shows the step of pressing where the press particles 67 and the conveyor 68 are pressed by the press table 24 on the surface 2. Figure 14c shows the relief structure 17 when the conveyor 68 with the press particles 67 is removed after pressing, and a surface of Perfect digitally formed EIR is obtained, which can be coordinated with any type of P fingerprints without any conventional press plates. A part of the surface structure, especially the microstructure 16 which provides the gloss level, can be formed by the carrier. The deep relief structures 17 are formed by the press particles and the conveyor 68.
[00307] BAP engraving provides the advantages that a deep engraving can be formed with only one or a few steps of applying BAP, since considerable amount of press particles 68 can be applied with thin layers of ink blank 11. This method allows the engraving depth D to exceed the vertical extent V of the ink blank spots 57 that connect the press particles to the conveyor.
[00308] Figure 14d shows a method for forming the surface 2 of a panel with BAP engraving. An ink blank station 36 applies ink blank 11 onto a conveyor 68 which, in this embodiment, is preferably aluminum foil, or a coated release paper. A dry paint application station 27 is used to apply press particles 67 onto the conveyor. An IR lamp 23 can be used in some applications to create an application link. The press particles are removed by a dry ink removal station 28, and the carrier with the press particles is pressed against the substrate by a press table 24. The carrier and press particles are then removed, and a BAP relief structure is formed.
[00309] The method can be used to form a conventional recording, or an EIR recording.
[00310] The surface of the conveyor 68 that is pressed against the etched surface 2 can be coated, such that different gloss levels or microstructures can be obtained. Such coating is preferably digitally produced according to a method described in this disclosure.
[00311] The press particles 67 can be attached to the conveyor with all the methods described above. For example, the heating print heads 80 and laser 29 can be used.
[00312] Figures 15a-15d show that the BPA Transfer Printing Method can be combined with the BPA Recording Method. Press particles 67 can be applied to one side of a conveyor, 68 and a BAP print can be applied to the opposite side of conveyor 68 which comprises a transfer surface 18, as shown in Figure 15a. Carrier 68 can be a sheet, paper, and the like, as described above. BAP printing can also be replaced with a conventional digital printing, or even with a printing provided with conventional rollers. Preferably, the print P and the pattern of the press particles 67 are coordinated such that an EIR structure can be formed. Figure 15b shows that the conveyor 68 and press particles 67 together with the print P are pressed onto a surface 2. Figure 15c shows that the print P is attached to the surface 2, and that the conveyor 68 with the particles of press 67 forms an embossed structure 17 when removed after the pressing operation. Applying the press particles 67 and printing dry ink can be done in-line with the pressing operation, as shown in Figure 15d, or as a separate operation where a pre-printed and pre-etched carrier 68 is formed, which can be supplied as an individual carrier, preferably as a sheet. A combined BAP printing and recording equipment may comprise blank ink application stations 36, dry ink application stations 27, and dry ink removal stations 28, which apply and remove dry ink 15 and press particles 67 in the opposite sides of a conveyor 68.
[00313] The particles can also be attached to the conveyor with a laser beam, heating print heads, and all the other methods described above.
[00314] The surface of the conveyor 68 that is in contact with the surface of panel 2 can be pre-pressed, and different gloss levels, or microstructures, can be formed. Such pre-pressing can be done with conventional engraved cylinders, or with a BAP engraving method. Various levels of gloss and microstructures can also be formed with print scanning, and a coating can be produced according to any of the methods described in this disclosure. The conveyor 68 with the press particles 67, and preferably also with a transfer print P, can be supplied as a press die 78, and can be used to form an embossed structure in, for example, laminate, wood , and wood-based floors, but also in tiles and LVT floors. Press die 78 can be used multiple times. The P print can be a conventional print, a digital inkjet print, a BAP digital print, or the like.
[00315] The method can also be used to form a more durable "mirror-shaped" press die which can be a sheet material where protrusions on conveyor 68 form cavities in the sheet-shaped press die. The carrier with the press particles can be pressed against impregnated paper, preferably phenol-impregnated craft paper, or powder comprising a thermosetting resin, and a structured sheet matrix can be formed, which, in a second step, can be used as a press die. Metal powder and glass fibers can be included in order to improve strength and heat transfer properties.
[00316] All the methods described above can be partially or completely combined, in order to partially or completely create a fingerprint or and/or a digital recording.
[00317] Water-based paint blank can, in some application, be combined or replaced by oil-based paint or solvent. The advantage with oil-based ink can be that it has a very high drying time, and this can improve the function of the digital drop application head.
[00318] While illustrative embodiments of the invention have been described herein, the present invention is not limited to the various preferred embodiments described herein, but includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., aspects through various embodiments), adaptations and/or changes, as would be appreciated by those skilled in the art based on the present disclosure. The limitations in the claims are to be interpreted broadly based on the language used in the claims, and not limited to the examples described in this specification, or during the application proceeding, which examples are to be construed as non-exclusive.EXAMPLE 1 - INK EM WHITE INCLUDING WATER AND GLYCOL
[00319] A blank ink formulation was produced by a Piezo Kyocera printhead designed for inks with a viscosity of 5-6 cps. 60.8% deionized water was mixed with 38.0% Polyethylene Glycol PEG 400, 1.0% Surfynol wetting agent, and 0.2% Actidice MBS for bacterial and fungal control. DRY FIBER-BASED PAINT
[00320] Dry paint powder was produced by mixing 20% (weight) of spray-dried melamine formaldehyde particles, 20% of dark brown color pigments, 60% of pine wood fibers with an average length of about 0.2 mm and a bristle thickness of 0.05 mm. The mixture was applied as a 1 mm thick layer by diffusion equipment on a belt. The powder mixture was then heated, and moisture was applied by deionized water vapor. The mixture was dried by hot air, such that a hard stabilized powder-based surface was obtained with a semi-cured melamine binder. The dried layer was removed from the belt by scraping, and the dried wood particles coated with pigments and melamine resins were ground and sieved in dry paint dyes of a size similar to the size of the individual wood fibers. A dry ink comprising dyes with a wood fiber body, and with a surface covered by pigments bonded to the fibers by semi-cured melamine resin, was obtained.EXAMPLE 3 - DIGITAL BINDER AND POWDER PRINT
[00321] An 8 mm HDF board was sprayed with small water droplets of deionized water and a 300 g/m2 powder mixture comprising wood fibers, melamine particles, light brown pigments, aluminum oxide particles , was applied by diffusion equipment in the HDF core. The mixture was again sprayed with deionized water comprising a release agent and dried by IR light, such that a partially semi-cured hard stabilized powder-based surface bonded to the HDF core, and with a light brown base color, was obtained. The panel with the stabilized powder surface was placed on a conveyor, and moved under the Kyocera digital Piezo printhead. The digital print head applies blank ink drops mainly comprising water and Glycol, with a formulation as described in example 1 above, on the powder-based surface stabilized with light brown color, and a clear liquid wood grain pattern was printed on stabilized powder-based surface. The wood grain pattern was positioned at a predetermined distance from a long and short edge of the panel. The melamine on the surface under the applied transparent pattern melts when the digital Piezo coating head applies water-based drops to the powder-based surface. The dry paint, as described in example 2 above, comprising a darker brown color than the basic light brown powder-based surface, was, in a second step, diffused under the total powder-based surface and the transparent pattern with a dry paint application station comprising a funnel and a rotating and oscillating engraved roller with a diameter of 5 cm. A layer of dry paint of about 30gr/m2 was applied to the panel surface. The melamine in the dry ink fibers that were in contact with the clear ink-blank pattern melted, and the dry ink particles were bonded to the stabilized powder surface. The panel with the transparent white ink pattern and the dry ink layer was then moved by a conveyor under IR lamps. The melamine in the clear pattern was dried again, and a stronger bond of the fibers with the pigments above the clear pattern was obtained. The panel was then moved with a conveyor under a dry ink removal station comprising a vacuum suction profile with an aperture covering the entire width of the applied dry ink layer, where essentially all the fibers were not bonded with the pigments were removed, and an air knife which applies air pressure to the remaining unbound particles which were released from the panel surface and blown into the vacuum suction profile such that essentially all visible dry paint particles were removed. A wood grain pattern comprising a light brown base color and dark brown wood grain structures were obtained. A protective layer comprising drying a mixture of dry melamine and aluminum oxide particles was diffused over the total surface with the same type of diffusion station as described above for the ink blank. The protective layer was sprayed with small drops of water comprising a release agent, and dried under IR lamps. The panel with the print and protective layer was then positioned in a predetermined position relative to a long and short edge in a hydraulic press, and pressed against an embossed plate for 20 seconds at a temperature of 170C° and 4 MPa (40 bar) pressure, and the powder-based surface with wood grain pattern and protective layer have been cured to a hard wear resistant surface with a high quality fingerprint coordinated with the structure of embossed surface. The panel decoration was created by a basic color and a wood grain design comprising wood fibers and pigments. The copy obtained from a wooden design was very realistic as natural wood fibers were used to create the visible pattern.ACHIEVEMENTS
[00322] 1. A method of forming a fingerprint (P)on a surface (2), in which the method comprises the steps of:
[00323] • apply colorants (7) on the surface (2);
[00324] • bond a part of the colorants to the surface (2) with a binder (11); and
[00325] • remove unbound dyes (7) from the surface (2), such that a fingerprint (P) is formed by the bound dyes (7).
[00326] 2. The method, according to embodiment 1, in which the dyes (7) comprise pigments (12) mixed with the binder (11).
[00327] 3. The method, according to embodiments 1 or 2, in which the binder (11) comprises a thermosetting resin.
[00328] 4. The method, according to any one of the preceding embodiments, in which the binder (11) comprises a thermoplastic resin.
[00329] 5. The method, according to any of the preceding embodiments, in which the binder (11) is a powder.
[00330] 6. The method, according to any of the preceding embodiments, in which the surface (2) is a layer of paper or a sheet.
[00331] 7. The method, according to any of the preceding embodiments, in which the surface (2) comprises a layer of powder.
[00332] 8. The method, according to any of the preceding embodiments, in which the surface (2) is a part of a building panel (1).
[00333] 9. The method, according to any of the preceding embodiments, in which the surface (2) is a part of a floor panel (1).
[00334] 10. The method, according to any of the preceding embodiments, in which the dyes (7) are removed by a current of air.
[00335] 11. The method, according to any of the preceding embodiments, in which the binder is a blank ink (11) comprising a liquid substance which is applied by a digital drop application head (30').
[00336] 12. The method, according to any of the preceding embodiments 1-10, in which a laser beam (29) or a heating printhead (80) produces the bond.
[00337] 13. The method according to embodiment 11, in which the liquid substance is water-based.
[00338] 14. The method, according to embodiments 11 or 13, in which the liquid substance is exposed to IR light (23) or hot air.
[00339] 15. The method according to embodiment 14, in which the liquid substance (11) is exposed to UV light.
[00340] 16. The method according to embodiment 14, in which the liquid substance is applied with a Piezo ink head.
[00341] 17. The method according to embodiment 14, in which the liquid substance is applied with a thermal ink head.
[00342] 18. The method, according to embodiments 16 or 17, in which the liquid substance is applied with drops (56) arranged in a grid (R1 - R4), and in which the dyes (7) are bonded with several drops.
[00343] 19. The method, according to any of the preceding embodiments, in which the dyes (7) have a particle body (66) comprising fibers (61) or mineral material (63).
[00344] 20. The method, according to any of the preceding embodiments, in which the surface (2) with the bound dyes (7) is pressed.
[00345] 21. The method, according to any of the preceding embodiments, in which the surface (2) with the bound dyes (7) is heated and pressed.
[00346] 22. The method, according to any of the preceding embodiments, in which the surface (2) comprises other color than the dyes (7).
[00347] 23. The method, according to any of the preceding embodiments, in which the method comprises additional steps of applying new dyes (7, 12b) with a different color to the first bound dyes (7, 12a), and to the surface (2), binding a part of the new dyes (7, 12b) to the surface with a binder, and removing new unbound dyes (7, 12b) from the surface, such that a fingerprint (P) is formed with the first (12a) and the new (12b) colorants positioned side by side on the surface (2).
[00348] 24. The method, according to any of the preceding embodiments, in which the dyes (7) are applied by diffusion.
[00349] 25. The method, according to any of the preceding embodiments, in which the dyes (7) are arranged in a wood grain pattern or a limestone pattern.
[00350] 26. The method, according to any of the preceding embodiments, in which the surface and dyes are pressed and cured to a hard surface with an embossed structure (17).
[00351] 27. The method, according to any one of the preceding embodiments, in which the dyes (7) are macro-dye particles (64) larger than 20 microns.
[00352] 28. The method, according to any of the preceding embodiments, in which the dyes (7) are pressed onto the surface (2).
[00353] 29. The method, according to any of the preceding embodiments, in which the surface (2) is a part of a panel (1) that is a laminate floor or wooden floor, a wood-based floor , a tile, or an LVT floor.
[00354] 30. An apparatus (40) for providing a digital print (P) on a surface (2), comprising a digital drop application head (30'), a dry ink application station (27), and a dry ink removal station (28) in which:
[00355] • the digital drop application head (30') is adapted to apply liquid white ink (11) on the surface (2);
[00356] • the dry ink application station (27) is adapted to apply dry ink (15) comprising dyes (7) on the surface (2);
[00357] • the ink blank (11) is adapted to bond a part of the dry ink (15) to the surface (2); and
[00358] • the dry ink removal station (28) is adapted to remove unbound dyes (7) from the surface (2).
[00359] 31. An equipment, according to embodiment 30, in which the surface (2) is a part of a panel (1).
[00360] 32. An apparatus, according to embodiments 30 or 31, in which the dry ink (15) comprises a resin.
[00361] 33. An apparatus, according to any one of the embodiments 30-32, in which the ink blank (11) is water-based.
[00362] 34. An apparatus, according to any one of the embodiments 30 - 33, in which the paint blank (11) is exposed to increased temperature after application.
[00363] 35. Dry ink (15) comprising macro-dye particles (64) for binding to a liquid print (P) applied to a surface (2), in which the macro-dye particles (64) comprise a body of particle (66) and color pigments (12) affixed to the particle body (66).
[00364] 36. Dry ink according to embodiment 35, in which the macro-dye particles (64) are larger than 20 microns.
[00365] 37. Dry ink, according to embodiment 35 or 36, in which the particle body (66) is a mineral particle (63), a fiber (61), or a thermosetting resin (13).
[00366] 38. Dry ink, according to embodiment 35 or 36, in which the particle body (66) is a mineral particle (63).
[00367] 39. Dry ink, according to embodiments 35 or 36, in which, the particle body (66) is a fiber (61).
[00368] 40. Dry ink according to any one of embodiments 35-39, in which the particle body (66) is coated with a resin.
[00369] 41. Dry paint according to embodiment 40, in which the resin is a thermosetting resin (13).
[00370] 42. Dry ink according to any one of embodiments 35-41, in which the liquid print is water-based, and applied by a digital drop application head (30').
43. A panel (1) with a surface (2) comprising a digitally formed print (P) of macro dyes (64) comprising a particle body (66) and color pigments (12) affixed to the surface of the particle body (66), in which the dyes (7) are arranged in patterns with pigments (12) on an upper and lower surface of the particle body (66).
[00372] 44. A panel according to embodiment 43, in which the particle body (66) comprises fibers (61).
[00373] 45. A panel according to embodiment 43, in which the particle body (66) is a mineral particle (63).
[00374] 46. A panel, according to any one of embodiments 43 - 45, in which the macro dyes (64) have a particle size exceeding 20 microns.
[00375] 47. A panel, according to any one of the preceding embodiments 43-46, in which the macro-dyes (64) form a solid print with overlapping decorative particles.
[00376] 48. A panel according to any one of the preceding embodiments 43 - 47, in which the panel (1) is a laminate or wood floor, a wood-based floor, a tile, or an LVT floor .
[00377] 49. A method of forming a digital recording (17) on a surface (2) by bonding hard press particles (67) to a conveyor (68) comprising the steps of:
[00378] • providing a liquid binder (BP) pattern on the conveyor (68) by a digital drop application head (30') which applies a liquid substance (11) on the conveyor;
[00379] • apply the hard press particles (67) on the conveyor (68) and the binder pattern (BP), such that the hard press particles are bonded to the conveyor (68) by the liquid binder pattern (BP);
[00380] • removing unbound hard press particles (67) from the conveyor (68);
[00381] • pressing the conveyor (68) with the crimping particles attached (67) to the surface (2); and
[00382] • remove the conveyor (68) with the crimping particles (67) from the pressed surface (2).
[00383] 50. The method according to embodiment 49, in which the press particles (67) are mineral particles (63).
51. The method, according to embodiments 49 or 50, in which the carrier is a paper or a sheet.
[00385] 52. The method according to any one of the preceding embodiments 49-51, in which the liquid substance is water-based.
[00386] 53. The method, according to any one of the preceding embodiments 49 - 52, in which the surface (2) is a powder, or a paper, or a sheet.
[00387] 54. The method according to any of the preceding embodiments 49 - 53, in which the surface (2) is a part of a panel (1).
[00388] 55. A panel (1) having a surface (2) with a wood grain decoration comprising a first surface portion (SI) which is formed by a continuous base layer comprising wood fibers (61a) having a first color, and a second surface portion (S2) which is formed by wood fibers (61b) having a second color, in which wood fibers (61b) having the second color are applied to and bonded to the continuous base layer, and wherein the second surface portion (S2) covers a part of the first surface portion (SI).
[00389] 56. The panel according to embodiment 55, in which the continuous base layer is a powder comprising a thermosetting resin.
[00390] 57. The panel, according to embodiments 55 or 56, in which the continuous base layer is a paper.
[00391] 58. The panel, according to any one of the embodiments 55 - 57, in which the second surface portion (S2) comprises fibers smaller than the first surface portion (SI)
[00392] 59. An equipment for providing a digital print (P) on a surface (2) with a transfer printing method, in which the equipment comprises a digital drop application head (30'), an application unit of dry ink (27), a dry ink removal station (28), and a transfer surface (18) in which:
[00393] • the digital drop application head (30') is adapted to apply liquid white ink (11) on the transfer surface (18);
[00394] • the dry ink application unit (27) is adapted to apply dry ink (15) comprising dyes on the transfer surface (18);
[00395] • the ink blank (11) is adapted to bond a part of the dry ink (15) to the transfer surface (18);
[00396] • the dry ink removal station (28) is adapted to remove unbound dry ink from the transfer surface (18); and
[00397] • the transfer surface (18) with the dry ink attached is adapted to be pressed against the surface (2).
[00398] 60. An equipment, according to embodiment 59, in which the dry ink (15) comprises a resin.
[00399] 61. An apparatus, according to embodiments 59 or 60, in which the ink blank (11) is water-based.
[00400] 62. An apparatus, according to any one of the embodiments 59 - 61, in which the paint blank is exposed to the increased temperature after application.
[00401] 63. A press die (78) for forming a relief structure (17) in a panel (1), in which the press die comprises hard press particles (67) arranged in a pattern and bonded to a carrier (68) being a coated paper or a sheet.
[00402] 64. A press die (78) according to embodiment 63, in which the hard press particles (67) are arranged on one side of the conveyor, and a print (P) is arranged on the opposite side of the conveyor.
[00403] 65. A press die (78) according to embodiment 63 or 64, in which the hard press particles (67) and the print (P) are coordinated such that an embossed printed surface on record can be obtained when the press die is pressed against a panel surface (2).
[00404] 66. A method of forming a fingerprint (P)on a surface (2), in which the method comprises the steps of applying dry ink powder (15) comprising dyes (7) on the surface, attaching a part of dry ink powder (15) to the surface (2) by a digital heating print head (80), such that the digital print (P) is formed by the bonded dyes of dry ink (7), and removing dry ink does not connected (15) from the surface (2).
[00405] 67. The method according to embodiment 66, in which dry ink (15) comprises a heat sensitive resin.
[00406] 68. The method according to embodiment 66 or 67, in which the surface (2) comprises a heat sensitive resin.
[00407] 69. The method, according to embodiments 67 or 68, in which the heat sensitive resin is a thermosetting resin, or thermoplastic resin.
[00408] 70. The method according to embodiment 69, in which heat sensitive resin is a thermosetting resin comprising melamine.
[00409] 71. The method according to any one of embodiments 66 - 69, in which the heating printhead (80) applies heat to a heat transfer sheet (81).
[00410] 72. The method according to embodiment 70, in which the heat transfer sheet (81) comprises copper or aluminum.
[00411] 72. The method, according to any one of the embodiments 66 - 68, in which the surface (2) is a part of a building panel, preferably a part of a floor panel (1).
[00412] 73. The method according to any one of the embodiments 66 - 72, in which the dry ink (15) comprises mineral particles.
[00413] 74. The method according to embodiment 73, in which dry ink (15) comprises aluminum oxide particles.
[00414] 75. A method of forming a digital print (P) on a surface (2) comprising applying drops (57) of blank ink (11) by a digital drop application head (30') on the surface ( 2), and attaching dyes (7) to the drops (57) of the ink blank for forming the fingerprint (P), in which the fingerprint (P) comprises another color than the ink blank (11).
[00415] 76. The method, according to embodiment 75, in which the other color is formed by dyes (7) bonded to the surface (2) by blank ink (11).
[00416] 77. The method, according to embodiments 75 or 76, in which the ink blank (11) is essentially a transparent liquid substance comprising water.
[00417] 78. The method, according to any one of the embodiments 75 - 77, in which the ink blank (11) forms a first and a second part of the print (P), and in which the ink blank, the first and second parts all comprise different colors.
[00418] 79. The method, according to any one of the embodiments 75 - 78, in which the fingerprint (P) comprises dyes (7) with different colors positioned horizontally apart in the same plane.
[00419] 80. The method, according to any one of embodiments 75-79, in which the vertical extent (V2) of the dyes (7) exceeds the vertical extent (VI) of blank ink drops (57).
[00420] 81. The method according to any one of the embodiments 75 - 80, in which the digitally applied blank ink drops (57) penetrate downwardly and upwardly from the surface (2) after application.
[00421] 82. The method according to any one of embodiments 75-81, in which the ink blank drops (11) providing an ink blank spot (57) on the surface (2) bind dyes (7 ) having a size that is larger than the ink blank spot size (57).
[00422] 83. The method, according to any one of the embodiments 75 - 82, in which the ink blank (11) is applied in a grid pattern (R1 - R4), and in which the ink dries (15) is randomly applied with dye overlay (7).
[00423] 84. The method, according to any one of embodiments 75 - 83, in which the horizontal extent (H2) of individual dyes (7) exceeds the horizontal extent (HI) of the ink dots (57), and the vertical extension (V2) of the dry ink layer, after removal of unbound particles, preferably exceeds the vertical extension (VI) of the ink blank spots (57).

权利要求:
Claims (14)
[0001]
1. Method of forming a fingerprint (P) on a panel (1) comprising a surface (2), the surface being a part of a building panel (1), such as a floor panel (1), characterized in that it comprises: moving the panel under a digital drop application head (30'); applying a liquid binder (11) with the digital drop application head (30') on the surface (2); applying dyes ( 7) in the liquid binder (11) and on the surface (2), the dyes 7 being dye macro particles (64) larger than 20 microns; bond a part of the dyes (7) to the surface (2) with the li - liquid gant (11); remove the unbound dyes (7) from the surface (2) such that a fingerprint (P) is formed by the bound dyes (7); and apply heat and pressure to the panel (1), the surface (2), and the bonded dyes (7), such that the dyes (7) are permanently bonded to the surface (2), and the dyes (7) are pressed into the surface (2) when heat and pressure are applied to the panel (1).
[0002]
2. Method according to claim 1, characterized in that at least one between the surface (2) and the dyes is compressed by the step of applying heat and pressure on the panel (1), on the surface (2) and in bound dyes (7).
[0003]
3. Method according to claim 1 or 2, characterized in that the liquid binder (11) comprises glycol or glycerin.
[0004]
4. Method according to any one of the preceding claims, characterized in that the surface (2) comprises a material that is curable under heat and pressure.
[0005]
5. Method according to any one of claims 1 to 3, characterized in that the surface (2) comprises a material that is fusible under heat and pressure.
[0006]
6. Method according to any of the preceding claims, characterized in that the surface (2) comprises a thermosetting resin (13) which is cured with the step of applying heat and pressure, such that the dyes (7 ) are permanently bonded to the surface (2) with the cured thermosetting resin.
[0007]
7. Method according to any one of the preceding claims, characterized in that the surface (2) comprises a layer of powder.
[0008]
8. Method according to any of the preceding claims, characterized in that the liquid binder (11) is applied as drops (56) arranged in a grid (R1 - R4), and in which the dyes (7) are connected with several drops.
[0009]
9. Method according to any one of claims 1 to 8, characterized in that the liquid binder (11) comprises 10 - 70% of water and 30 - 90% of glycol and/or glycerin, by weight.
[0010]
10. Method according to any of the preceding claims, characterized in that the surface (2) comprises a dry formaldehyde melamine resin (13) which melts when the liquid binder (11) is applied, and which binds the colorants (7) on the surface (2).
[0011]
11. Method according to any one of the preceding claims, characterized in that the dye macro particles (64) comprise pigments (12) fixed to a particle body (66).
[0012]
12. Method according to any of the preceding claims, characterized in that the dyes (7) each have a particle body (66) comprising wood fibers (61).
[0013]
13. Method according to any of the preceding claims, characterized in that it comprises the additional steps of applying new dyes (7, 12b) with a different color in the first bound dyes (7, 12a) and on the surface (2) , binding a part of the new dyes (7, 12b) to the surface (2) with a binder (11) and removing the new unbound dyes (7, 12b) from the surface, so that a fingerprint (P) is formed with the first (12a) and new (12b) colorants positioned side by side on the surface (2).
[0014]
14. Method according to any of the preceding claims, characterized in that the dyes (7) are applied in the liquid binder (11).

类似技术:

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US11014378B2|2021-05-25|Digital embossing

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BR112015016163B1|2021-08-17|METHOD OF FORMATION OF A DIGITAL PRINT ON A PANEL

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BR112015016240A2|2021-05-25|digital recording

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BR112015016197B1|2021-08-10|METHOD OF FORMATION OF A FINGERPRINT ON A SURFACE

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ES2846001T3|2021-07-28|Dry ink for digital printing

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ES2848179T3|2021-08-05|Digital printing with binder and powder

同族专利:

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公开号 | 公开日

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BR112015016163A8|2021-05-11|

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EA201591261A8|2016-05-31|

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CN105008139B|2019-08-13|

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EP2943346A1|2015-11-18|

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CA2896942C|2021-08-24|

---

EP3868565A1|2021-08-25|

---

CN105008139A|2015-10-28|

---

EA201591261A1|2015-11-30|

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CA2896942A1|2014-07-17|

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KR20150109384A|2015-10-01|

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UA115893C2|2018-01-10|

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JP6457949B2|2019-01-23|

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EP2943346B1|2020-12-02|

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EP2943346A4|2016-08-31|

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EP3825137A1|2021-05-26|

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MX2015008767A|2016-04-11|

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MY170619A|2019-08-21|

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PL2943346T3|2021-05-17|

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AU2014205716A1|2015-08-13|

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CN110341336B|2022-01-25|

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EA030050B1|2018-06-29|

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BR112015016163A2|2017-07-11|

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CN110341336A|2019-10-18|

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AU2014205716B2|2018-04-19|

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WO2014109699A1|2014-07-17|

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JP2016514058A|2016-05-19|

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法律状态:
2018-02-27| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|

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2018-03-27| B25A| Requested transfer of rights approved|Owner name: CERALOC INNOVATION AB (SE) |

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2019-10-22| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2021-06-22| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-08-17| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 10/01/2014, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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US201361751418P| true| 2013-01-11|2013-01-11|

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US61/751,418|2013-01-11|

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SE1350021|2013-01-11|

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SE1350021-0|2013-01-11|

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PCT/SE2014/050019|WO2014109699A1|2013-01-11|2014-01-10|Digital binder and powder print|

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