• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to a method for controlling a printing process, wherein at least one position and / or an extent of a register mark located on a printing material (101) is detected by means of a register mark sensor (131, 132, 133, 134) and used for register control, characterized at least one color information is recorded during the printing process by means of the same register mark sensor (131, 132, 133, 134), with which a color monitoring is carried out, wherein a color distance to a reference value is determined and a threshold for the color distance is defined, when exceeded a warning is output and / or automatically switched from good to bad products. The invention thus provides the possibility of simultaneous control and / or measurement of the position (register control) and color with a single detection device. The effort and costs for a color and register control can be significantly reduced, since in particular the measurement of the color information is not performed with expensive camera systems, but with cheaper brand sensors.
    公开号:AT511258A2
    申请号:T304/2012
    申请日:2012-03-13
    公开日:2012-10-15
    发明作者:Holger Schnabel；Stephan Schultze
    申请人:Bosch Gmbh Robert；
    IPC主号:
    专利说明:

    * * - 1/14 -
    Method for controlling a printing process
    description
    The present invention relates to a method for controlling a printing operation according to the preamble of patent claim 1, a computing unit for performing the method, a register mark sensor and a control system for a printing press.
    State of the art
    In multicolor printing, for example, in rotary printing presses, the application of the individual color separations takes place, in particular for cyan, magenta, yellow and black, in successive printing units. The printing material is provided as a roll material and passed endlessly through the printing unit. Decisive for the achieved print quality is that the print images of the individual colors are exactly on top of each other. The superposition of the printed images is referred to as a register. For mutual alignment of the individual printing units register marks, for example in the form of registration marks, triangles, etc., printed in addition to the actual printed image of each printing unit. Using these marks, an offset between the individual print images can be recorded online by means of an optical measuring system. In rotary printing systems, this measuring system is generally part of a control system, the so-called register control. The register control intervenes in the printing process via suitable actuators and compensates for register deviation lines detected by the optical measuring system (detection device, register mark sensor). In particular, the actuators can change the web length of the printing material between successive printing units so that the printed images of successive printing units are superimposed. -2 / 14-
    The detection devices used are contrast sensors, color sensors or cameras which typically operate in reflection. The material web is illuminated constantly or pulsed with a suitable light source (white or colored light) and the reflected light is detected and evaluated by the sensor.
    Prior to scanning by contrast or color sensors, a teach-in process is usually performed in which a signal threshold is learned by using " mark " and " no mark " a distinction is made. The time of the sampling in which the signal to be evaluated exceeds or falls below the signal threshold is assumed to be the time of the contrast transition. From DE 10 2008 049 908 A1 a color-sensitive register mark sensor is known, which carries out an evaluation of at least two color information for better recognition of the register mark position. This means that even low-contrast register marks can be reliably detected. A color scheme is not treated.
    In addition, a color control or color check is carried out during printing. Today, this is increasingly done as so-called inline color control during the printing process, whereby color measurement fields (color control strips) are detected by means of special color sensors. An in-line color control is described, for example, in DE 10 2004 021 599 A1.
    A disadvantage of the prior art is that relatively many and complex detection devices for register control and color control are necessary, Furthermore, in addition to the register marks and the color measurement fields are printed, which increases the need for printing ink, which is relatively expensive in certain cases.
    It is therefore an object to provide an improved method for controlling a printing process, which requires less effort,
    Disclosure of the invention
    According to the invention, a method for controlling a printing process with the features of patent claim 1 is proposed. The invention further includes a computing unit for carrying out the method, a register mark sensor and a control system for a printing press having the features of the independent patent claims. Advantageous embodiments are the subject of the subclaims and the following description. «* * · -3 / 14- * ·« «* • * * * Mt · J · · * · • · *
    Advantages of the invention
    The invention makes use of a color-sensitive register mark sensor (intensity sensor) in order not only to register register mark positions or expansions, but also color information, and to use these in each case for the corresponding regulation or monitoring. The invention thereby provides the possibility for a simultaneous control and / or measurement of the position / extent (register control) and color with a single detection device. The effort and costs for a color and register control can be significantly reduced, since in particular the measurement of the color information is not performed with expensive camera systems, but with cheaper brand sensors. In this context, it should also be mentioned that the color resolution of color cameras is generally worse than that of brand current sensors or that for a high color resolution in cameras a variety of special filters between camera chip and print material must be changed sequentially, resulting in a long measurement time.
    A color monitor is performed to automatically respond to excessive color variation. By using register mark sensors, the color sensitivity in the printing machine can be increased so that a deviation or a trend can be detected at an early stage. Due to the early warning waste can be avoided. If there is still waste, it can be sorted out automatically. In addition, a color control can be provided, in which case the color monitor helps to compensate for color control inadequacies.
    It is advisable to also capture the at least one color information at a register mark, so that additional color measurement fields can be omitted. This reduces the pressure as well as the ink requirement and thus the costs. In this case, the acquisition takes place exclusively at register marks. However, it may alternatively or additionally be provided to continue to capture the color information on special color measurement fields.
    When determining the colors and their evaluation, different color spaces can be used. For example, CIE-L * a * b *, C1E-L * u * v *, DIU99, RGB, CIE XYZ, CIE xyY may be mentioned for this purpose. The CIE-L * a * b * color space is particularly suitable since a Euclidean distance determined there matches very well with the human color perception. -4 / 14-
    Conveniently, a polarization filter is used to detect the color information to reduce noise. Inline measured densities are wet values, which depend on the combination of printing ink, paper, dampening solution. The brand current sensor 5 is usually relatively close behind a printing unit. As a result, the applied color in your moisture may differ from the learned reference color information. Furthermore, the humidity of the register marks may differ even with different material web velocities. It may be provided according to a further embodiment of the invention, a
    To capture tonal change. Depending on the printing ink and printing material, the color is assumed differently. This means that e.g. due to a greater absorbency of a paper, a pressure point appears enlarged (dot gain). In the print this is noticeable by a stronger color impression. This tone behavior can be determined by means of 15 special color fields having different color densities (e.g., 10%, 20%, ..., 100%).
    Color density) are calibrated. Although the sensor detects the same color every time (for example, in the xyY color space), the brightness information (color saturation) will be different each time. On the basis of the measuring fields, the ink acceptance behavior of the sensor can thus also be measured. This characteristic can be used to characterize the ink in combination with the mechanics of the ink keys and the substrate in their overall transfer behavior.
    Preferably, a first threshold is defined for a color difference to a reference color. If this first threshold value is exceeded, the operator is expediently given a warning signal. The first threshold should be set so that if it is exceeded no waste is produced. Thus, the operator has the opportunity to check the color in good time and if necessary to intervene manually in the color composition. In addition, a second threshold value can be provided which, when exceeded, automatically switches from good to bad products. This can e.g. via a so-called waste gate, which then removes the bad products from the production stream.
    In a further preferred embodiment, a trend display of the changes of the color information can be provided. Thus, the long-term development of the color information is -5 / 14-f * · · I «• • • • • 4 4 4 4 4 4 4 4.
    and to see changes in the composition of the color particularly easy. Similar visualization may be provided to demonstrate the effects of the control. For example, the amount of solvent added and the resulting change in color information (gradient detection) are recorded. From this information, the operator can gain manual experience. Furthermore, these effects can be learned automatically by the control system.
    If color information is measured by register marks, the results are dependent on the background color. In particular, the same printing ink gives different colors on different printing materials (e.g., types of paper). If not only the colors of the print marks but also the color of the background are measured, the color control can not only regulate an absolute color, but also a fixed color locus in relation to the respective background color. Also, preset values of color control values, e.g. were determined from formulations of previous print jobs, based on the background color of the substrate of the old print job and the current substrate are changed such that a changed background color does not lead to another printed color.
    An arithmetic unit according to the invention, e.g. a control unit of a printing press, is, in particular programmatically, adapted to perform a method according to the invention.
    Also, the implementation of the invention in the form of software is advantageous because this allows very low cost, especially if an executing arithmetic unit is still used for other tasks and therefore already exists. Suitable data carriers for providing the computer program are, in particular, floppy disks, hard disks, flash memories, EEPROMs, CD-ROMs, DVDs and the like. It is also possible to download a program via computer networks (Internet, intranet, etc.).
    Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawings.
    It is understood that the features mentioned above and those yet to be explained not only in the combination given, but also in other combinations.
    • · < · · «
    Combinations or alone, without departing from the scope of the present invention.
    The invention is illustrated diagrammatically by means of an embodiment in the drawing and will be described in detail below with reference to the drawing.
    figure description
    Figure 1 shows schematically a section of a printing machine with a control system according to the invention, in which the inventive method is implemented.
    In FIG. 1, a processing machine configured as a printing press is designated by 100 as a whole. A printing material, for example paper 101, is fed to the machine via an infeed 110. The paper 101 is guided and printed by processing devices designed as printing units 111, 112, 113,] 14 and reissued by an outfeed 115. The input, extraction and printing units are positioned, in particular zyiinder- or angle-correctable arranged. As products, the printing machine prints on the paper 101, which are composed of the applied by the printing units III, 112, 113, 114 Teilbiidem.
    The printing units 111 to 114 each have a printing cylinder 11 'to 114', against which a respective impression roller (counter-pressure point) 111 " to 114 " is employed with strong pressure. The impression cylinders are individually and independently driven. The associated drives 111 " ' to 114 "' are shown schematically. The impression rollers are freely rotatable. The printing units 111 to 114 together with the continuous paper 101 form a non-positively connected unit (nip). The drives of the individual plants are connected to a computing unit (e.g., controller) 150 via a data link 151. Furthermore, there are a plurality of sensors 131, 132, 133, 134 for detecting register marks, which are also connected to the controller 150 between the printing units. For clarity, only the sensor 134 is shown connected to the controller.
    * «* * '* * -7 / 14-
    In the web sections between the individual printing units 111 to 114, the paper 101 is guided over unspecified rollers, which are partially designated 102. For reasons of clarity, not all rollers are provided with reference numeral 102. In particular, these may be deflection rollers, drying, cooling or trimming devices, etc.
    Below is described how in the illustrated printing machine register control, for example. A longitudinal and / or side register control is performed. For a register-based printing, the sub-images printed by the printing units 111 to 114 must be in the correct position one above the other. To determine the processing position (printing position) of the partial images, a so-called register mark is printed with each partial image. These register marks are detected by the detection units 131, 132, 133, 134 formed as mark sensors.
    One way to characterize known register methods is to consider the reference quantities that are used to determine the deviation of the positions of the partial images from their desired positions. This differentiation option makes it possible to differentiate between train / rail method and rail / cylinder method.
    In a web / cylinder process, the position of a predetermined register mark and the position of a printing cylinder (for example, determined by means of a rotary encoder) are compared during the passage of the web. In a web / web method, the positions of a predetermined register mark and a further register mark are compared during the passage of the web. In both cases, a respective register deviation can be calculated. The detected register deviations are used to position the printing units -one of the measured and, on the other hand, those that printed the further register mark.
    If the predetermined register mark is the mark applied by the preceding printing cylinder in each case, this is called predecessor color control. If the predetermined register mark is always the same register mark (which is preferably applied by the first printing unit), the term color control is used.
    fc · * · • Μ • · -8 / 14-
    According to one embodiment of the invention, the sensors 131-134 are used to detect not only the longitudinal and / or side register position of the printing units 114, but also color information. In this case, each of the sensors 131-134 expediently also detects the color information of the register mark assigned to it. It is also possible that only one sensor is provided behind the last printing unit, i. only the sensor 134, which then detects all brands. The color information is preferably the color density or a color distance to a previously defined or taught during teaching reference color. This design can save additional color sensors. In order to improve the detection of the color information, it is expedient to use a 45 ° / 0ο or a 0 ° / 45 ° geometry (irradiation angle / detection angle).
    A provided in the sensor or associated with this evaluation evaluates both the brand lengths, eg. The mark distances, as well as the color information and gives this information to one or more control systems, here the controller 150, on. Preferably, the controller 150 is set up in terms of programming in accordance with a preferred embodiment of the invention and executes both the control algorithms for the register control and for the color monitoring and optionally color control. Thus, an automated regulation of the brand position and printing unit color can be done. Furthermore, appropriate warnings can be issued. In an embodiment of the invention, the sensor itself comprises evaluation electronics (so-called smart sensor) and is connected to the controller 150 directly via the data connection 151, for example a fieldbus connection. The sensor transmits to the controller a first signal for register control and a second signal for color monitoring and preferably also color control.
    In order to determine color change in the printing process, a reference is expediently determined. For this purpose, three preferred alternatives are described below:
    It is possible to specify the reference color by a teach process (Einlemen). Before printing, a teach operation is usually performed to bring in the register marks in the expectation window for the sensor. During the teaching process, for example, different threshold values are calculated for the later measurement. The expectation window is either set manually by the user or automatically determined by the sensor (for example, barcode search).
    The teaching process is started precisely when the desired color composition is present, i. the sensor determines threshold values for the position measurement and simultaneously or subsequently the corresponding color values from the register mark current or from additional color measurement fields. The corresponding color values can be read out and can, for example, be stored in a recipe. The color values determined in this way are taken over as the reference value for the measurement. 5
    Alternatively, color density and reference value can be taken from a template or from pre-press. In this case, the correct colors are already learned by the sensor before the actual printing process on the basis of the print template (for example reference colors or a first printed "good product"). Here, the colors of either the 10 register mark stream or a print control strip with different
    Color fields are learned. It is expedient to measure several color densities of a color in different fields in order to enable the sensor to be assigned directly to different color densities. The incorporated values are used in the printing process for comparison with the then printed register marks. Alternatively, the colors 15 of the measured marks or color measurement fields can be transmitted from a pre-press (in digital form) to the color control.
    Finally, it can also be provided to specify the reference values manually from a recipe. The reference values (for example, determined once as described above) are loaded into the sensor 20 before the start of printing, thus ensuring that the
    Color compositions of the same print jobs even after temporal interruptions completely agree. The sensor acquires the color information in the register mark Ström or the color measurement fields and compares them with the recipe values. Thus, color control and register control can be performed at the start of printing. 25 During the printing process (in a continuous process, so to speak), the mark sensor detects the applied register mark (s). It evaluates the results of the brand position (s) (for example, zero pulse) and determines the color information. The determined
    Color information is compared with the reference values. The color difference can be calculated, for example, as a Euclidean distance (distance between two color loci), where the following applies for the CIELab color space: δε, .. = rrr-Ly + (a; -ay + (b; ~ b: f 4 ♦ « «* 4 · 1 -10 / 14-« · »· · ·
    Furthermore, AE / AE or AEQQ can also be calculated as the color difference. The calculated
    Color spaces and positions are conveniently transmitted via an Ethemet bus or via a real-time interface (e.g., Sercos 111) to the controller 150 where the appropriate position and color control algorithms operate.
    The color and position information determined from the register marks for the purposes of the invention are expediently transmitted to a control system. On the control system, both the control algorithms for the position control and for the color control are performed in a preferred embodiment. The controller can execute freely programmable control algorithms in your Logic part in order to derive the corresponding positional adjustment. For the color control further interfaces are created with which the control can intervene on the color control. For example, the supply of water or solvent can be automated, if the color consistency has changed and this was detected by means of the measurement from the register mark current.
    Furthermore, the controller 150 is set up by the program for a threshold value comparison. For this purpose, a first and a second threshold for the color distance are specified. If the first threshold value is exceeded, the operator is given a warning signal via a warning device 140, for example a screen and / or a warning lamp. The first threshold is set so that if it is exceeded no waste is produced. Thus, the operator has the opportunity to check the color in good time and if necessary to intervene manually in the color composition. This is intended for cases in which the color control is insufficient to correct deviations. When the second threshold value is exceeded, a waste gate 141 is automatically switched over in order to discharge bad products from the production flow.
    权利要求:
    Claims (15)
    [1]
    Claims 1. A method for controlling a printing operation, wherein by means of a register mark sensor (131, 132, 133, 134) at least a position and / or an extent of a register mark located on a printing material (101) is detected and used for register control, characterized in that at least one color information is detected during the printing operation by means of the same register mark sensor (131, 132, 133, 134) a color monitoring is carried out, wherein a color distance is determined to a reference value and a threshold for the color distance is defined, is exceeded when a warning is issued and / or automatically switched from good to bad products.
    [2]
    2. The method of claim 1, wherein additionally using the at least one detected color information, inline color control is performed.
    [3]
    3. The method of claim 1 or 2, wherein the at least one color information is detected at the register mark.
    [4]
    4. The method according to claim 1, wherein, based on the at least one detected position of the register mark located on the printing material, a distance of the register mark to another register mark or a distance of the register mark from a reference event from the register mark sensor (131, 132, 133, 134).
    [5]
    5. The method according to any one of the preceding claims, wherein based on the at least one color information, a color density and / or a color distance to a reference value from the register mark sensor (131, 132, 133, 134) is determined.
    [6]
    6. The method of claim 5, wherein the reference value from a teaching process, a template from the prepress or a recipe is determined. · ♦ * * * * * * t 9 ϊ * * I * -12 / 14-
    [7]
    7. The method according to any one of the preceding claims, wherein in the detection of the color information, a polarizing filter is used.
    [8]
    8. The method according to any one of the preceding claims, wherein a combined and automatic control of the register and the color is performed by a computing unit.
    [9]
    9. The method according to any one of the preceding claims, wherein a first threshold is defined for the color distance, when exceeded, a warning is issued, and a second threshold for the color distance is defined, is automatically switched when switching from good to bad products.
    [10]
    10. The method according to any one of the preceding claims, wherein a trend display of the changes of the color information is provided.
    [11]
    11. The method according to any one of the preceding claims, wherein a background color in the color measurement is taken into account and compensated.
    [12]
    12. The method according to any one of the preceding claims, wherein a Tonwertveränderung is detected.
    [13]
    13. A computing unit (150) adapted to perform a method according to any one of the preceding claims.
    [14]
    14. register mark sensor (131, 132, 133, 134) for detecting a register mark located on a printing material (101), which is adapted to at least detect a position and / or an extent of a register mark on a printing material (101) associated output first signal for a register control and to detect at least one color information and output a corresponding second signal for color monitoring and / or inline color control.
    [15]
    15. register mark sensor (131, 132, 133, 134) according to claim 13, with an interface for a field bus, in particular a real-time capable, Ethernet-based fieldbus, in particular Profinet IO, SERCOS III, EthcrCat or Powerlink, which is adapted to the first Output signal and the second signal at the interface. 6. A control system for a printing press, wherein at least one register mark sensor (131, 132, 133, 134) according to claim 14 or 15 directly with a computing unit (150) according to claim 13 for transmitting the first and second signals 5 communicates. 1 March 3rd, 2012 PATEN! ήΪ P1: PP.P. 'i - P- i ü k; t Cif I 3 I 33 i oi' i-ri'MER cs '· ^' Pi Pi <, 3 f.
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    同族专利:
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    AT511258A3|2015-11-15|
    引用文献:
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    WO1999024263A1|1997-11-10|1999-05-20|Oce Printing Systems Gmbh|Method and device for conveying a pre-printed striplike recording medium in a printing device|
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    US9616655B2|2013-12-19|2017-04-11|Goss International Americas, Inc.|Method for reducing web printing press start-up waste, and related printing press and printed product|
    JP6548909B2|2015-02-25|2019-07-24|住友重機械工業株式会社|Registration control unit, multi-color printing system including the registration control unit, and method of detecting a registration mark|
    JP6341870B2|2015-02-25|2018-06-13|住友重機械工業株式会社|Register control unit, multicolor printing system including register control unit, and register control method|
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    法律状态:
    2016-01-15| REJ| Rejection|Effective date: 20160115 |
    2016-05-15| REJ| Rejection|Effective date: 20160515 |
    优先权:
    申请号 | 申请日 | 专利标题
    DE102011014073A|DE102011014073A1|2011-03-16|2011-03-16|Method for controlling a printing process|
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