EP0884178B1 - Process for regulating the inking in a printing machine - Google Patents

Description

The invention relates to a method for Regulation of the coloring when printing with a printing press. The invention is the devices are particularly applicable to printing presses for handling, printing and treating sheets or other surfaces to be printed. The invention is used for control and rules of operations that the Coloring of an arch, a path or one Influence the printed product significantly.

State of the art are methods and devices for Control and regulation of operations on printing machines, which cutting and folding devices are subordinate. To the Controlling and regulating the coloring and the cutting and Fold registers are used when transporting a sheet or a Web through the printing units on the surface of the Colored printing material next to an actual printed image Print control strips, registration marks and others Register marks created.

For color control, it is known to use color measurements in Color fields of a certain color of the print control strip Gain actual values for color control; see e.g. EP-A-0 228 347. It is also especially known for spot and special colors, actual values for the color control from image areas printed in full tones to win. The color measurement in the color fields or in the Spot image areas can be inside the press or be done offline outside the press, for what a sample sheet is removed from the process and one Color measuring arrangement is supplied. The preferably opto electronically obtained color measurement values can be sent to a control and Control circuit are passed where they are with Setpoints are compared and in manipulated variables for Control elements of a color distribution device converted become.

For register setting facilities are known that have online acting register mark sensors, which on in Register mark traces with printed register marks directed are. There are also offline working facilities at those with a register cross reader the accuracy of Fitting crosses is measured and the measured values then said machine control are passed on where Generated manipulated variables for the register setting devices become.

A disadvantage of these solutions is that the measuring locations for the Actual value determination of the items to be controlled or regulated Company sizes through those used for quality assurance Color measuring fields, register crosses and register marks are fixed are. The production of these measurement marks generated in the Prepress a considerable effort.

The accuracy of such color measuring fields and registration marks is due to assembly, copying and development errors in the Prepress limited. Furthermore, they do not limit to print control strip and the actual print image Fitting crosses for the print image on the substrate Available space. The color measurement fields of a Print control strip, which is usually the actual one Upstream print image in the transport direction of the substrate or arranged below are only limited representative of the printed image. The offline color measurements delay the color control process, with until adjustment a lot of waste occurs in an okay state. Undefined Drawing times, especially when the Condition of the printing press, lead to problems such as B. overshoot in the color control. Furthermore, they are previous solutions regarding the choice of the color measurement location inflexible. A subject-dependent choice of color measurement by The operator of the printing press is in the solutions after State of the art not provided. Furthermore, the Operator through offline color measurement using a larger period with the handling of the test objects and the Color and register measuring device deals. The operator there is no complete information about the Trend of the color and register setting available.

As for the different to be controlled or regulated Operations separate sensors for each Actual value acquisition must be provided, the increase Effort and costs for the control and regulation of more than two operations simultaneously.

The object of the invention is a method to develop that the operator at Quality assurance supports and complements that a selection a representative color measurement site either by hand or automated that enables fast regulation ensures that the amount of waste is reduced and that the effort and the costs for the control or regulation of operations of a printing press decreased.

According to the invention, the object is achieved by a method which has the features of claim 1.

A device for control or regulation of operations of a printing machine, with which the procedure can be carried out consists of at least one image recording device that on the Surface of the printed product is directed and with a control and regulation circuit is connected. The tax and Image information can be supplied to the control circuit Play the surface of the printed product. For Influencing the operations within the printing machine stands the control and Control circuit in connection with actuators.

Embodiments of the invention result from the Dependent claims.

The effect of the invention is described below become:

From those reflecting the surface of a printed product Image information is first generated using the control and Control circuit the coordinates for the measuring locations of the Image acquisition device determined. The image information for The determination of the coordinates can be from different sources come from. A first possibility is that the Image information taken from the image recording device be arranged in the printing machine and the one for scanning the surface of a Printed product is directed. To do this, the whole Surface or only parts of it can be scanned.

If the printing press is a printing press, and the image recording device preferably a last one Printing unit following the surface of a sheet or one Web is directed, then the image information can be used Determination of the coordinates for the measuring locations of one in the Setup phase generated print image can be obtained. Since the Image recording device not only detects the printed image, but also the remaining area of the arch or a path, it is possible to use the procedure and set up for the purpose the material identification or material testing of the Use printing material, especially to determine the Whiteness or luminance level or to determine Color fluctuations or material defects, such as stains or Holes.

If the printing machine is used exclusively for Inspection of printed matter is trained, then can the image information, with the help of the image recording device, from the surface of any one to be inspected Printed matter can be obtained.

Another way to get coordinates for the measurement sites determine is to use image information which are taken from an image recording device, which is an image of the surface of the printed product outside scans the printing machine. More options result from the fact that the image information with the help generated by a digital computer that is part of a Device for imaging is, or that already available image information taken from a data memory become.

The selection of a suitable measuring location for a specific one Operation can be done with the help of a computer that be arranged within the control and regulating circuit can. For example, in the case of an offset printing press Color scheme, dampening solution management and register are regulated or to be controlled, then coordinates for the Measuring locations of each of these operations determined.

A program runs in the computer that contains the appropriate ones Measurement locations. To control the color of a printing press e.g. B. automatically determined from the image information measuring locations be in a color control strip and / or lie in the printed image itself. Said program ensures that the measuring point is significant for determining the actual value of a or more defined colors. For a color control A measuring point of a printing press is significant if as much color information as possible for the respective color contains. Suitable measuring points for color control found, for example, within dark gray areas. At Spot and special colors are the measuring points in solo standing colors, preferably in the 3/4-tone range. In the Measuring point determination can be particularly critical tones are taken into account so that, for example, the measuring point for a subject in which furniture is depicted, in one brown-toned area or in a portrait in one flesh-colored area is determined. The information about which of the critical at the respective pressure Color tone, the facility can be pre-arranged can be entered.

Such significant measuring locations are used for humidity control determined that in color-free areas in the scanning direction seen behind 3/4 tone areas or full tone areas.

Suitable measuring locations for register control can be found in the Print image with register cross-like structures, such as. B. thin lines and sharp edges, such as in the illustration of masts, antennas or windows in one Subject are present.

In a further step the Print products with the help of in the printing Machine arranged image recording device to the predetermined measuring locations scanned. The actual picture signals are the control and regulation circuit fed, where they in one Comparator with target values from a reference variable encoder be compared. For everyone to be controlled or regulated Operating process, separate actual values are defined Measuring locations determined and compared with separate setpoints. To gain actual value for everyone to be regulated or controlling operations is per printing machine only one image acquisition device required. The tax and Control circuit can be separate for each operation Facilities, comparators and reference gauges included. It is possible that for several each with one Imaging device provided printing machines a common control and regulation circuit is provided, then a switching device receiving the Actual image signals from the individual image recording devices and the distribution of the control signals to the individual Control elements for influencing company variables takes over. In any case, the tax and Control circuit control signals output to the respective Influence the operation in the desired way.

The control and regulation circuit can be in a control console be housed and in conventional analog and digital circuit technology or implemented with fuzzy logic his. The operator can control and Control circuitry interact, for which the control console a computer with a high resolution screen, with a alphanumeric keyboard, with a cursor control device and with an input and output device for data can be assigned.

On the screen, the image from the surface of a Printed matter including that of the tax and Control circuit specific measuring locations are shown, where the measuring locations can be specially marked. Likewise, on an actual image, a difference image, measured values of Operating variables and manipulated variables are displayed. The operator has the ability to control or regulate the Operations by interfering with the coordinates of the Measuring locations, the setpoints of operating variables or the Manipulated variables changed.

The image recording device can be on a plane guided or on a on the outer surface of a cylinder transported printed product. To this Way, it is possible not only in operations To control or regulate dependence on image signals originate from the surface of the printed matter, but also depending on image signals from the surface of the facilities transporting the printed matter come from. An example is a gripper control which on the basis of the image signals, which the location of the Printed matter relative to the the printed matter in the Grippers holding transport devices include the Controls gripper opening times. As Image acquisition devices are all for photometric measurements suitable image sensors can be used, such as discrete color selective photodiodes and transistors, row and matrix-shaped CCD light receiver or Color picture tubes. The working wavelength depends according to the type of image sensors used, so that both Thermal radiation, IR radiation, visible light or UV radiation than that containing the image information Radiation can be used. The image recording device can Lens flare mode or work in transmitted light mode. The The angle of incidence and angle of exit for the measuring light is Adjusted reception characteristics of the image sensors. The Image acquisition device is suitable for the entire width of the To scan the printed product. A cheap variant exists in a measuring bar that spans the entire width of the Printed product is arranged, with image signals from the actual printed image, but also signals from registration marks or Register marks and from the areas between the printed image and the edges of the printed product. If necessary, individual image sensors can be desensitized become. Another constructive variant results with an image recording head that traverses across Printed product transport direction is arranged, which is why Image recording head with a positioning device including drive, length and angle measuring system is coupled. In this way, the Image recording device on a defined scanning track be directed in the significant picture elements or the Registration marks are included. The change in the scanning angle as well as a focusing movement with the help of separate control devices are automated so that an optimal signal-to-noise ratio is always achieved. It is possible to use an arrangement to compensate for errors, that are caused by highlights, to provide that for example in the form of crossed linear polarizers Image sensors are connected upstream.

Based on the control or regulation of operations A printing press is said to have further advantages of the device to be discribed:

It is a particular asset of the facility that it helps the image recording device described above for Print quality assurance is very flexible. The The main application for a printing press is in simultaneous image inspection and color control, for which the Image acquisition device Color measurement values directly from the printed image records. The color measurement values are preferably photometric according to the three-range method or with the help of a spectral measuring device won. The spectral sensitivity of the measuring channels arranged in the image recording device for each area corresponds to the spectral value curves of one Normal observer. The image sensors themselves can have defined spectral sensitivity or Image sensors with essentially the same sensitivity are used to filter the spectral value curves of the Adjusted normal observer. The image sensors can e.g. B. in arranged in a row, scanning the printing material zone by zone, the zone width can be variable, for which purpose signals from Image sensors can be captured accordingly in groups. The scan zones can correspond to the zones from the Color distribution device of the printing press are specified. If in a scanning zone for one or more subjects, depending on the subject Colors there is no suitable measuring location, then can be used Color control Measured values from neighboring zones can be used. It is possible to do the complete with the image recording device Capture print image. However, only a part of the Printed image can be scanned. A special facility ensures that the same scanning location is found in every printed copy is detected. This can be done from stored image measurements previous measurement cycles are taken, whereby a Scanning location detection is possible. To determine the As described above, the scanning location can emit signals Devices for measuring the position of the substrate with respect to a reference location that the Control circuit are supplied so that a correlation of the Measured position values for the image signals are carried out.

In order to create a sub or Avoiding overdriving the image sensors can Receivers are arranged a light attenuation arrangement. Furthermore, the intensity of the measuring light in Depending on the speed of the substrate or be regulated by the contrast at the measurement location, for what corresponding devices for speed measurement or for contrast measurement in connection with the measuring light source have to stand. The speed can be from the signals an incremental encoder can be obtained with the the cylinders that support the substrate is coupled.

In the same way, the image recording device can also have one co-printed outside the actual print image Detect print control strips. The print image sensors are then exactly at the time of passing the Print control strip initiated. In a variant you can with the image recording device both signals from the actual print image as well as from the print control strip be won.

On Part of the elements belonging to the facility becomes Image inspection used. So that one Achieve overall quality control. For this, the Image acquisition device used as an online measuring arrangement. As with online color measurement, one becomes Comparison of the actual image data with reference values rough Color deviations and register errors, toning, pushing and Duplicate and a. Errors detected and displayed on the screen. Furthermore, through the entire printing material image inspection defects in and on the substrate, such as B. cracks, holes, edge irregularities of the Substrate, inclusions, slugs and printing errors other mechanical influences can be seen. The signals of the comparison resulting from the image inspection will be where possible control elements of the printing press to influence various operations are supplied and / or Devices supplied for display and / or for Serve quality documentation.

An example of image inspection is the monitoring of Moisture control in an offset printing machine. You can do this e.g. B. those obtained with the image recording device Image data from the area of the start of printing over the entire Width of the substrate can be continuously evaluated. If the evaluation shows that the lubrication limit has been reached then the dampening solution distribution devices and where appropriate, the color distribution devices adjusted that the ink / fountain solution balance optimal production printing allowed.

Another example of image inspection is the monitoring of the paint and powder application on the Substrate. The image recording device is as Gloss measuring device formed. It is possible to To provide a separate highlight source, the at a defined angle of incidence on the Printing material shines. It is also possible to Highlight measurement using at least one in the Image recording device arranged receiver light evaluate whose level of incidence and default is not in Transport direction of the printing material lies. The for color measurement or for image inspection Light source and receiver arrangement are used, wherein the secondary light striking a receiver is detected.

Another application of the facility at a Printing press is the register regulation. In doing so Actual image signals from registration marks, register marks or other picture elements significant for the register evaluated and compared with target image signals.

A register control device indicates signals Register actuators, both in terms of Image position to the substrate edges as well as with regard to the individual color images to each other a correction of the register cause.

With the help of the press control, a selection can be made above-described applications are made. It is also possible not to take all measurements on everyone Make printed image. For data processing reasons it may be useful, for example, to inspect the image perform each print copy while the color and Register measurements on every second or nth printed copy be carried out and / or averaging over several printed copies are carried out. It is the same possible, the number of measuring locations on a printed copy and to change the frequency of measurements at a measuring location. You can also depend on these use cases can be switched from process variables. For example, if the Control deviation is too high in one of the applications, then the press control can ensure that in this application, especially many actual values with the Image recording device are generated. Such a case can for example when the press starts up or at There may be deviations due to duplication.

For the transmission of the signals reproducing the image an optical image guide can be used, whose light entry surface is divided into partial areas, the sub-areas of light from the substrate from individual Record scanning zones. Then at the light exit surface Photoelectric receiver elements are provided, each are assigned to one of the scanning zones and the luminous flux convert into electrical signals.

In any case, that of the image recording device generated signals of a device for processing Image signals supplied. The transmission of the image signals between the image recording device and the Processing device can also be wireless without Image conductor cables are made when used by the image sensors recorded information about an electromagnetic, acoustic or optical transmission and reception path be transmitted. Such a transmission link it is not necessary if the processing device is located locally Image acquisition device is assigned. The facility for Processing of the image signals allowed depending on the operating mode the image recording device a data reduction, so that a optimal control time is guaranteed.

The processed image signals are the Comparator supplied and with reference signals compared, which can be found in a reference value generator. As A memory can be used as the reference variable encoder Contains target image data from a previous print job for the same print image. It is also possible that the memory contains target image data from the measurement a gut sheet with all colors and / or Individual color extracts of a gut sheet can be obtained. This Measurement only needs to be carried out once, for which the Press control can contain a program which the required color separations in response to a control signal delivers and initiates the measurements. From the measured values according to the grid, z. B. the area coverage of the individual colors and together with the Color setpoints from the color measurement on the good sheet in the Storage filed. The remissions of the Individual colors are measured and saved, which means that the conventional, empirical determination and storage of Color tables are omitted. That kind of Providing reference sizes is especially important when printing with more as the four process colors, cyan, magenta, yellow and black, advantageous, with only one for a printing press Image acquisition device is required. To increase the Calculation accuracy when solving this Common Neugebauer equation can also use color separations for any color combination z. B. Black / Cyan; Black / magenta; Black yellow; Cyan / magenta; Cyan / yellow and Magenta / yellow, printed, measured and their remission get saved.

The production and measurement of color separations is also part of Calculation methods useful without knowledge of the Area coverings, e.g. B. only with remissions or from it determined colorimetric or density values works. This This makes it possible to provide reference values is not limited to the determination of the area coverage and can all necessary knowledge about single colors and their deliver different combinations.

Another way of providing benchmarks is that the reference signals an image measuring device can be taken from a template that is appropriate for the stand was scanned. The offline image measuring device and the online imaging device can be from be of the same type. Drawing files can also be used as templates a scanned template are scanned, then to position the drawing files as they are on the should be arranged according to the template Reference source of layout signals can be supplied.

Another way of providing benchmarks results from the fact that the operator of the printing press a signal for data transfer to the reference variable encoder is given when the operator is visually and based on Measured values make the decision that the press is on is in a high-quality production state. In In this case, the processed actual image signals are as Transfer setpoints to the reference variable.

Furthermore, the reference signals can be a setpoint memory are taken from the control device of the printing press assigned. All are in the setpoint memory Data processing usual storage media, such as. B. Semiconductor memory, floppy disks, magnetic tapes and optical Memory, usable. The reference signals can be obtained from the operator corrected or changed by hand. Likewise, the Operator the possibility of global reference signals as a percentage to change.

If in the result of the comparison between target and actual values the output signal deviates from a limit value, then can an error signal is generated and output. A variant is that an acoustic signal is emitted. If to Interaction of the operator with the machine control and with the color control a computer with an alphanumeric keyboard and cursor control device, as well as with a screen is provided, then the error signal can be optically on the Screen are generated, where on the screen Actual image and the specially marked faulty ones Images can be displayed. The markings of the defective image areas can be simple, for example be geometric figures or in the form of a visually good visible false color representation. In addition to the pictorial representation of the error can then, if the Control circuit is assigned an error detection logic the processed image signals or from the signals after the Comparator device to determine the type of error and can also be output on the screen. The mistakes can u. a. classify into the following types of errors: Color errors, register errors, dampening errors, slugs, Flaws in the substrate, impurities in the Substrate and edge breakout in the substrate.

Exceeding the limit of the difference between Target and actual image values can also be used for one Sheet printing machine cause the incorrectly printed Sheets are discarded at a waste paper lock, whereby alternatively, a marking device, such as one Ink-jet printing device that can be provided defective sheet or parts of the respective sheet indicates.

To monitor the quality of a print job, the Target / actual deviations are documented in intervals. For example, one described above Markers are used every 50th sheet or printed image with a serial number, the time of measurement and to print the amount of the target / actual deviation. At a sheetfed press can simultaneously Strip shooter actuated on the boom stack become. In addition, those printed on the sheets quality documentation data are stored and at Required as a log with error statistics be issued. The logged measurement data of the Sample sheets can be placed outside the press using a calibrated color difference measuring device preferably homogeneous measuring locations of the printed image can be checked again. The invention will be described in more detail with reference to drawings are explained.

Fig. 1

ein Schema einer Steuer- oder Regeleinrichtung für eine Druckmaschine,

Fig. 2

eine Bildaufnahmeeinrichtung mit vier verschiedenen Abbildungssystemen,

Fig. 3

eine Bildaufnahmeeinrichtung mit genau einem optisch abbildenden System,

Fig. 4

eine Bildaufnahmeeinrichtung mit einem Linsenarray,

Fig. 5

ein Schema für eine Signalgewinnung an einem Zylinder an einer Bogendruckmaschine,

Fig. 6

eine optoelektronische Signalverarbeitung,

Fig. 7

ein Schema für die Korrektur und die Farbwertsignalspeicherung der Bildsignale,

Fig. 8

ein Schema für die Differenzbildauswertung.

Show it:

Fig. 1

a diagram of a control or regulating device for a printing press,

Fig. 2

an image recording device with four different imaging systems,

Fig. 3

an image recording device with exactly one optical imaging system,

Fig. 4

an image recording device with a lens array,

Fig. 5

a diagram for signal acquisition on a cylinder on a sheet-fed printing press,

Fig. 6

optoelectronic signal processing,

Fig. 7

a scheme for the correction and the color value signal storage of the image signals,

Fig. 8

a scheme for the differential image evaluation.

In the scheme shown in Figure 1 one Color control system with the help of drive elements 1 a Web 2 for double-sided printing by printing units 3, 4 one Roll rotary printing machine 5 promoted. The printing units 3, 4 contain color distribution devices 6, 7, 8, 9 which contain conventional zonal color metering elements and the in Transverse direction to the transport direction 10 of the web 2 Generate a defined color profile. The web 2 is in contact with rubber cylinders 11, 12, 13, 14 set for pressure in one pass through the web-fed rotary printing press 5 printed multicolored on both sides. The last printing unit 4 following are one each on the top and bottom of the web 2 Image recording device 15, 16 provided in Bearings 17, 18 pivotable and in guides 19, 20 vertically are displaceable to the transport direction 10. The Image recording devices 15, 16 capture the entire width lane 2 and each contain at least one Light source 21, 22 and a variety of photoelectric Receivers 23, 24. To record the speed and the Angle of rotation of the rubber cylinders 11, 12, 13, 14 and the Transport speed of the web 2 is one of the one Gear train coupled rubber cylinder 11, 12, 13, 14 with an incremental encoder 25 coupled. The phase of Rubber cylinder 11, 12, 13, 14 is with the help of Register setting devices 26, 27, 28, 29 changeable. All to control and regulate the operations of the Web-fed rotary printing press 5 necessary elements are included connected to a machine controller 30, which in a Control panel 31 is arranged. The machine control 30 contains input and output points 32 for tax and Control signals. The connections shown in Fig. 1 and arrows point to the entry and exit points 32 schematically the information flows and their directions. Furthermore, the machine control 30 contains the hardware and Software and at least one control circuit 33 Control circuit 33 includes u. a. a device 34 for Processing the image signals, a comparator 35, a Reference size transmitter 36, a control device 37 and a Error detection logic 38. The device 34 for processing of the image signals stands with the photoelectric Receivers 23, 24 of the image recording devices 15, 16 in Connection. The output of the device 37 for processing of the image signals is with an actual value input of the Comparator 35 connected, a setpoint input of the Comparator 35 in conjunction with the reference value transmitter 36 stands. The output of the comparator 35 is one Input of the error detection logic 38 and the Control device 37 in connection. A control exit of the Fault detection logic 38 is the one with a blocking input Control device 37 connected. The exit of the Control device 37 is connected to the via an output point 32 Color dosing elements in the Color distribution devices 6, 7, 8, 9 connected. The Output of the control device 37 is still with the Register setting devices 26, 27, 28, 29 connectable. On the control panel 31 is a computer 39 with a Screen 40, a keyboard 41 and one Cursor control device 42 arranged. The bus system of the Computer 39 is in via a further input / output point 32 the machine control 30 performed. Are on the bus system Data from an external image measuring device 43, data from a Computer network 44 of the print shop and data from one Dial-up modem 45 and the output data from the comparator 35 and the error detection logic 38 can be switched on. The Dial-up modem 45 is with an external transmission and Receiving unit 46 connected. At an issuing point 32 an acoustic signal generator 47 to the machine control 30 connected.

The mode of operation of the system shown schematically in FIG. 1 Color controller should be described in the following:

According to the number of color zones through the Color distribution devices 6, 7, 8, 9 are determined in the image recording devices 15, 16 across the width of the Lane 2 evenly distributed along a line Light sources 21, 22 are provided. With the help of elliptical The light is reflected under a defined one Angle of incidence thrown on the web 2. Each Light source 21, 22 is from a programmable Power source controlled so that the color temperature of the Light sources 21, 22 can be regulated. In addition, the Actual luminous flux of each light source 21, 22 with the help of Optical fibers are detected. The one from Bahn 2 reflected measuring light can be optically imaging system on the photoelectric receivers 23, 24 be transmitted. The luminous flux from a picture element the web 2 runs out, is proportional to the signal charge one Photodiode of a CCD line used as a receiver 23, 24. For calibration and adjustment are the Image recording devices 15, 16 perpendicular to Transport direction 10 displaceable and around the bearings 17, 18th pivotally arranged. This can be a focus and a Error compensation of the image recording device 15, 16 can be achieved. In a swiveled out position Image recording devices 15, 16 can calibrate based on a color standard. That `s how it is possible to compare the Image recording devices 15, 16, the light source 21, 22 or the photoelectric receivers 23, 24 or only parts thereof in Are arranged displaceably in the direction of the optical axis. There the color measurement in the printed image according to the so-called Tri-area, it is due to the different spectral properties of the optical measuring means and the photoelectric receiver 23, 24th required in the individual color zones, in the measuring beam path to provide spectrally matching components. A method for spectral matching is, in addition to that necessary for the implementation of the three-area process Main filter to provide correction filter glasses. At a Another method uses partial filters where the Neutral glass a variety of different color filters are cemented or sputtered. By additional application the areas of the individual color filter switched on or off, so that the spectral course can be influenced. In a simple one Arrangement are four cemented on a support plate Partial filter using a cross slide over a circular aperture positioned. To avoid The color filter and photoelectric can cause temperature errors Receiver 23, 24 with a thermostat at a constant Working temperature can be kept.

In Figure 2 is an image recording device 15, 16 with four different imaging systems 48, 49, 50, 51, facing the web 2 at the color filter 52, 53, 54, 55 are arranged. To adjust as a receiver 23, 24 acting CCD sensors 56, 57, 58, 59 relative to the imaging systems 48, 49, 50, 51 are the CCD sensors 56, 57, 58, 59 with adjustment elements 60 coupled.

In the variant shown in FIG. 3, only one is optical imaging system 61 provided, the Color filters 62, 63, 64, 65 are combined to form a block. A protective glass 66 is located in front of the color filters 62, 63, 64, 65 intended. The receivers 23 and 24 are fourfold CCD lines 67 provided on a common Adjusting element 68 are arranged. With this optical Arrangement will be in a color measurement in each Spectral ranges different image elements 69 on the four-fold CCD lines 67 shown, so that the one Pixel 69 belonging to different color measurement values Points in time. The spacing of the picture elements 69 of the CCD lines 67 and the optical properties of the optical imaging system 61 are coordinated.

FIG. 4 shows an image recording device 15, 16 with a Lens array 70 shown. The through the color filter 71st weighted image information is obtained with the lens array 70 coupled into an image guide 72. That at the exit of the Image guide 72 seated optical imaging system 73 brings the image information on a CCD sensor 74, which with Adjusting elements 75 is coupled. On the optically imaging System 73 can also be omitted if the glass fibers of the image guide 72 via a fiber optic window or directly are coupled to the CCD sensor 74. This optical Arrangement must be separate for each process color used be provided.

FIG. 5 shows a diagram for an actual signal acquisition a cylinder 76 of a sheet-fed printing machine. The arranged across the width of the cylinder 76 Receiver modules 77 are with the device 34 for Processing the image signals connected. The also modular constructed light sources 78 are provided with a device 79 for Light quantity regulation, which is also within the Machine control 30 is housed connected. For Synchronization and to provide a Preprocessing clock is within the Machine control 30, a synchronization device 80 and a timer is provided, which is connected to an incremental encoder 81 are connected.

For one equipped with CCD sensors 74 Image recording device 15, 16 is intended to process the signal within device 34 are described below:

The electrical generated by the CCD sensors 82 Image signals are sequentially one as shown in Figure 6 Amplifier 83, a sample-and-hold element 84 and one Analog-digital converter 85 fed. The exit of the Analog-to-digital converter 85 is with a digital Processing unit 86 connected, which u. a. the function of Control circuit 33 described in Figure 1 within the Machine control 30 takes over.

The correction of the image signals and is shown schematically in FIG the color value signal storage is shown and FIG. 8 shows schematically the difference image evaluation within the Processing unit 86. From analog-digital converter 85 the digital image signals arrive at a First correction element 87 equipped with memory units. This correction element 87 contains a look-up table Linearization of the characteristic curve of the converter elements of the CCD sensors 82. The data required for this is provided by Start-up of the system with a white balance different levels of control of the CCD sensors 82 obtained and stored in the correction element 87. The corrected Image signals become an input A of an accumulation unit 88 fed. With the help of the accumulation unit 88 different printing speeds controlled pixel-wise addition in connection with a Varying the integration time of the CCD sensors 82 compensated. The subtotals are in one Line memory 89 stored with an input B of Accumulation unit 88 is connectable. That way ensures that through the brightest part of the picture CCD sensors 82 at maximum speed of the Rotary printing machine 5 is still sufficient, for example with 50 X, can be modulated. At the minimal Print speed is multiple measurements within one Measuring line possible, for example eight samples Full control of a line of CCD sensors 82, so that in this example a maximum compensable Speed ratio of 1:16 results. At the same time the accumulation over n samples gives an improvement the signal-to-noise ratio at low Print speeds. The accumulation is such that too to the k-th at input A of the accumulation unit 88 Sampling of image data of the nth pixel, which during the (k-1) th scan formed from the line memory 89 read out and to the input B of the accumulation unit 88 Subtotals supplied are added. Then will the new subtotal to a memory location n + 1 cached. A timer 90 generates from the pulses of the incremental encoder 25 or 81, the addresses of the Line memory 89 and a list memory 91 and corrects the arising during the accumulation Address offset so that during the last accumulation the line memory 89 and an im List memory 91 contains shading memory synchronously to run. The timer 90 continues to supply the control signals and the multiplex clock for the CCD sensors 82. For example the data from eight rows of CCD sensors 82 on the input of the Correction element 87 are multiplexed. The timer will be 90 further signals about the thickness of the substrate 2 supplied, which was obtained with the aid of a thickness measuring device or that are already within the machine control 30 stand by. These signals are combined with the signals from the Encoder 25 linked so that the thickness of the Substrate 2 dependent speed and Measured position values for printing material 2 are corrected.

Processing unit 86 also contains one Multiplier 92 by means of which the input A pending accumulated image data from a last Accumulation of a measuring line and those at input B. reciprocal values of the standardized integration time with each other be multiplied.

A multiplier 93 connected downstream of the multiplier 92 causes a correction of the local intensity of the Light sources 21, 22 and 78 by the output signals the multiplier 92 with those stored in the list memory 91 Intensity correction factors are multiplied. The lists for the multipliers 92, 93 are also in the List memory 91 stored, which also the prediction values for contains the integration time control. The in List memory 91 stored list for shading correction is when starting the rotary printing press 5, as well the characteristic data of the input look-up table in Correction element 87 generated and running during a White value adjustment through selected blank image lines updated. At the output of multiplier 93 are from Level, print speed, shading and Sensor characteristic completely corrected image data synchronously via a pipeline bus 94 for further processing can be directed and the parallel to one Color value controller 95 are supplied. The Color value controller 95 is one Programmable gate array (PGA) circuitry using a AT bus 96, for example, the coordinates of the measuring fields the path 2 can be specified. The coordinates of the measuring fields for a certain color are with one of the actual ones Color control upstream process generated and on the AT bus 96 provided. Only for these measuring fields is with The color value controller 95 uses the color value of a pixel stored in a memory chip 97. The information this is done via control lines 98 of the pipeline bus 94 transfer. The memory module 97 contains the data Color vectors that can be read via the AT bus 96 for color measurement are. The pixels used for color measurement are in one Fine grid addressable. The measurement geometry can Fine grid can be shifted as desired and configured so that a better adaptation to given measurement geometries is realized.

In Figure 8, the further processing is complete corrected image data from all generated on web 2 Color zones or from all across the direction of transport 10 arranged modules of the image recording device 15, 16 shown. According to Figure 8 one in PGA technology executed data controller 99 the corrected Actual image data from across the entire surface of web 2 supplied to the bidirectional pipeline bus 94. The transfer the actual image data on the pipeline bus 94 can be in the Measurement pauses or carried out synchronously with the web scanning become. The data controller 99 is still with a Target image memory 100, a difference image memory 101, a parameter image memory 102 and an accumulated one Differential image memory 103 in connection. Loading the Data controller 99 and the selection of the operating modes takes place over the AT bus 96. The memories 100 to 103 are with a address controller 104 implemented in PGA technology, to the control lines 98 of the pipeline bus 94 connected. To evaluate the difference image and the accumulated difference image are the Differential image memory 101 and the accumulated Differential image memory 103 each with Look-up table blocks 105, 106 (LUT) in connection. The LUT 105, 106 use data from the Target image memory 100 and parameter image memory 102 Transformation of the difference image data to colorimetric LAB values of the LAB color space. The outputs of the LUT 105, 106 stand with a also realized in PGA technology Evaluation circuit 107 in connection. To the Evaluation circuit 107 is a memory module 108 connected in which the coordinates during the image measurement of a coarse grid for faulty image areas become. The data of the evaluation circuit 107 are via the AT bus 96 readable.

In a teach-in phase, the data controller 99 and the evaluation circuit 107 are configured so that the target image memory 100 and the accumulated difference image memory 103 are combined to form a common memory. A desired number m of accumulations can be entered to generate a target image. As a result, the corrected image data are multiplexed in the data controller 99, so that after 2 ^m accumulations the target image is present in the target image memory 100 in a normalized manner. The data controller 99 acts as an adder with an upstream multiplexer.

If target and parameter image data already in an external Memory are available, then you can use the Pipelinebus 94 using a not shown Forth processor loaded. The release of the desired one The address controller 104 ensures memory area.

After the data is generated in the memories 100 to 103 data controller 99 realizes an adder, which data for a current difference image from the Difference between the actual image data and the target image data. Furthermore, the data controller 99 realizes one Accumulator, wherein accumulated difference image data from the Sum of the data of an accumulated difference image and one current difference image are generated. On the Pipelinebus 94 can optionally display the current difference image, the accumulated difference image or the target image for Forth processor are transmitted. The selection is made via a status register in the address controller 104, which via the AT bus 96 is loaded. The synchronization of the Address generation and used for memory management Address controller 104 is performed by the on the Control lines 98 provided signals. The selection of the Operating modes take place via a control register. The Address controller 104 continuously ensures the refresh of Memory 100-103.

With the help of the LUT 105, 106 are during the image inspection depending on the parameter image data in Parameter image memory 102 and the absolute brightness that current difference image and the accumulated difference image rated. From the LUT 105, 106 the resulting data is assigned to the evaluation circuit 107 Difference image data error classes too. The error data will be for documentation and statistics in memory module 108 filed. If the amount of the difference image is one exceeds the predetermined limit, then the Evaluation circuit 107 an error message via the AT bus 96 discontinued. To do this, an address generator within the Evaluation circuit 107 in parallel to the address controller 104 Coarse grid, which is the location of the fault location facilitated. Fault location and type of fault are in the Memory chip 108 stored.

The parameter image memory 102 contains the control information about the processing of each individual pixel. The data in the target image memory 100 can use this Tax information to reduce a required non-linear characteristic curve used for error evaluation become. For this purpose, the following parameters are in the parameter memory 102 included: parameters for the edge markings, one Weight function for defining the weighting of image errors in the inspection process, color measurement values for a marked Pixel in a pointer-controlled list are stored, and the shading measuring points and Calibration points of the CCD sensors 82. By setting bits for the marginal markings the picture format is included the page limit. The parameters for the Weight functions provide a measure of error assessment This allows errors in homogeneous areas of the Print image stronger than defects in contours in the print image be weighted. Thereby a gray value dependent control used so that the colorimetric over the LUT 105, 106 Values x *, y *, z * and i * formed for image inspection become. The parameter expressed by the weight function is used in the address controller 104 for switching from Characteristic curves used. A table can be used with the help of Evaluation circuit 107 the assignment to different Error classes are made, with the errors in individual classes can be evaluated in terms of an error histogram.

via a separate control line 109 from Data controller 99 a bit ENC for controlling the color measurement spent. The pixels intended for color measurement are entered in a list in the order of their scanning, so that after further processing of the image measurement data by the Forth processor can be passed as color measurement values. For Shading measurement, the ENC bit is selected in a blank measuring line, so that at the same time a Measurement of the paper white value of web 2 is carried out. These measured values are also formatted as list data. The further processing, in particular the accumulation and the loading of the shading values is also carried out by the Forth processor adopted. To calibrate the Absolute sensitivity of the CCD sensors 82 and Color temperature of the assigned light sources 21, 22 and 78 a special element of a CCD line is provided, the also by the set bit ENC in the list memory is taken over and thus for further evaluation Available.

Reference list

1

Drive element

2nd

train

3, 4

Printing unit

5

Rotary printing press

6, 7, 8, 9

Color distribution device

10th

Direction of transport

11, 12, 13, 14

Rubber cylinder

15, 16

Image acquisition device

17, 18

camp

19, 20

guide

21, 22

Light source

23, 24

photoelectric receiver

25th

Encoder

26, 27, 28, 29

Register adjusters

30th

Machine control

31

control panel

32

Entry and exit points

33

Control circuit

34

Device for processing the Image signals

35

Comparator

36

Reference encoder

37

Control device

38

Error detection logic

39

computer

40

screen

41

keyboard

42

Cursor control device

43

Image measuring device

44

network

45

Dial-up modem

46

Sending / receiving unit

47

acoustic signal generator

48, 49, 50, 51

imaging system

52, 53, 54, 55

filter

56, 57, 58, 59

CCD sensors

60

Adjustment elements

61

optical imaging system

62, 63, 64, 65

Color filter

66

Protective glass

67

CCD lines

68

Adjustment elements

69

Picture elements

70

Lens array

71

Color filter

72

Image guide

73

optical imaging system

74

CCD sensor

75

Adjustment elements

76

cylinder

77

Receiver modules

78

Light source

79

Device for light quantity control

80

Synchronizer

81

incremental encoder

82

CCD sensor

83

amplifier

84

Sample & Hold link

85

Analog to digital converter

86

Processing unit

87

Correction link

88

Accumulation unit

89

Line memory

90

timer

91

List memory

92, 93

Multiplier

94

Pipeline bus

95

Color value controller

96

AT bus

97

Memory chip

98

Control lines

99

Data controller

100

Target image memory

101

Differential image memory

102

Parameter image memory

103

accumulated difference image memory

104

Address controller

105, 106

Look-up table blocks

107

Evaluation circuit

108

Memory chip

109

Control line

110

Data storage

Claims (4)

1. Method for regulating inking during the printing operation of a printing press wherein image signals are generated from at least one surface of at least one printed product by means of at last one image recording device, a print control strip being printed next to the printed image onto surface,

   wherein actual values representing inking are obtained from the image signals and compared to setpoint values in a closed-loop control device,

   wherein adjusting signals for the ink distribution devices are derived from the resultant comparison values, by means of which adjusting signals the inking of the printed product is influenced to reach a desired state, and

   wherein at the beginning of the printing operation, during a tuning phase, actual values taken from measurement locations in the print control strip are used,
   characterized in that, when the desired state is reached at the end of the tuning phase, an OK signal is generated from which on actual values taken from measurement sites in the printed image are used during a production run.
2. Method according to claim 1,
   characterized in that the actual values are obtained by means of the image recording device (15, 16) scanning the entire surface of the printed product (2) within the printing press.
3. Method according to claim 1,
   characterized in

   that during the tuning phase predetermined setpoint values are used and

   that the actual values at the end of the tuning phase are taken as setpoint values in the production run.
4. Method according to claim 1,
   characterized in that the point in time for ending the tuning phase is determined by the operator of the printing press (5).

Images