EP1843898B1 - Registering method - Google Patents

Abstract

A method for registering a rotary press for a printing process, in which “n” inking systems (Fn) each produce monochrome printed images and print one on top of the other thereby producing n-colored printed images, includes producing the images of a printed material with at least one sensor station, recording information on rotary movements of printing plate cylinders (Dn), and using the images and the information to produce correction signals which actuate the cylinders until a deviation of the images of the respective inking systems from a desired position on the material lies within a defined range of tolerance values. During the registering method, one printing plate cylinder at a time is in the printing position, the sensor station produces the printed images, and the correction signals are obtained based on the image produced by the respective cylinder and the information on the rotary movements of at least one cylinder.

Description

The invention relates to a method for registering a roation printing machine with a plurality of inking units.

Register procedure (eg US 5 056 430 A1 ) are known. One differentiates according to the effect of the register corrections to the printing material webs between longitudinal and

Cross tabs. In particular, the development of direct drive technology, which assigns at least each pressure plate-carrying cylinder its own drive, which can be controlled individually, has revolutionized the possibilities of registering. The provision of affordable sensor or camera systems has significantly improved the ability to provide readings even during the printing process.

Another way of distinguishing prior art registration methods is to consider the reference quantities used to determine the deviation of the position of the printed images from their desired position. By this differentiation possibility can be distinguished between train-rail method and rail-cylinder method. In the railway railway method (eg. DE 199 17 773 A1 ), the position of parts of monochrome print images on the substrate, which are already printed one above the other and thus form an already multicolored print image, compared. As a rule, these parts of the monochrome print images are register marks that are specially printed for this purpose by each inking register marks.

Due to the detected deviation of the position of the images of their target position correction signals are generated, the drives of the Actuate printing plate cylinder until the deviation of the position of their monochrome print images on the substrate is within a tolerance range. One of the weak points of this method is that registration can not occur when register marks are printed one above the other.

In the web-cylinder process (e.g. DE 42 18 760 A1 ) is sufficient to capture the location of a monochrome print image - usually a register mark - but once per inking unit. The position of this register mark at one time is related to information about the rotational movement of the respective printing plate cylinder. This information is usually in the form of trigger signals provided by encoders or simple switching devices.

In this, the position of the register mark on the current printing material at a time in relation to the input of the trigger signals is set to determine the correction signals.

This method requires one sensor system per inking unit.

The object of the present invention is to propose a register method that can manage with fewer sensor systems.

• dass während des Registerprozesses sich nacheinander jeweils ein Druckplattenzylinder in Druckposition befindet,
• dass die zumindest eine Sensorstation jeweils die entstandenen einfarbigen Druckbilder aufzeichnet und
• dass die Korrektursignale für den oder die Aktoren eines Druckplattenzylinders aufgrund des einfarbigen Bildes des jeweiligen Druckplattenzylinders und der Informationen zu den Rotationsbewegungen von zumindest einem Druckplattenzylindern gewonnen werden.

The invention is based on a web-cylinder method and thereby solves the problem

• in that one printing plate cylinder is in printing position one after the other during the register process,
• that the at least one sensor station in each case records the resulting monochrome print images and
• in that the correction signals for the actuator or actuators of a printing plate cylinder are obtained on the basis of the monochrome image of the respective printing plate cylinder and the information about the rotational movements of at least one printing plate cylinder.

The method according to the invention is particularly suitable for pre-registering. The pre-registration can be carried out particularly well here in an automated form. A camera system that is positioned in the web running direction behind the last inking unit inking system is sufficient. On the printing of register marks may possibly be completely dispensed with. Further advantages will be apparent in light of the subclaims and objective description. The following explanations serve to understand the present invention:

Even before or during a printing process in which not all inking units of a multicolor rotary printing press are used, the method according to the invention can be used. The images of printed substrate taken may be pieces of printed images, such as register marks, other image components, or even the entire image.

As a sensor station line cameras, photoelectric sensors and all sorts of sensors come into consideration. As already mentioned, the information about the rotational movements are often present in the form of trigger signals. However, all other types of sensor output signals - whether digital or analog, trigger signal or encoder signal - are conceivable. Also, the correction signals can be present in any conceivable form. As a rule, as in register methods of the prior art, they bring about a brief acceleration (increase or decrease in the peripheral speed) of the controlled cylinder, so that it approaches its desired position. When Querregistern the position of the printing cylinder is changed transversely to the direction of the printing material.

In the method according to the invention, a printing cylinder is usually located in the pressing position and produces monochrome printed images which are recorded by the at least one sensor station. Similar to a cylinder-web method, the position of the monochrome print image on the substrate at a time - when recording the print image by the sensor station - is related to information on the rotational movements of printing plate cylinders as their angular position plotted against time.

In this case, the information mentioned to a certain extent generates a temporal coordinate system with which the angular position of printing cylinders in relation to the recording time of the image can be set by the sensoration.

This temporal coordinate system then allows the comparison of the position of the single monochrome print images, which at different times of the at least one sensor station are recorded. The information about the rotational movements of printing plate cylinders may be, for example, average information about the rotational movements of a group of printing plate cylinders. Most likely, however, is that information be taken about the rotational movement of a single plate cylinder - preferably the one that is first set to the printing position. This pressure plate cylinder can then continue to turn during the entire register process and thus help to generate the information - for example, one trigger signal per revolution. If all information about the angular position of one or more printing plate cylinders can be called up, it is even conceivable to stop the printing plate cylinder (s) that hold the described master function during registering and to simply generate the master signal from the clock of a control device. Necessary, however, is a registergerechtes start the stopped cylinder, which makes great demands on the drives and their control. It is therefore preferable to have the master signal generated in the described form of one or more Druckplattenzylindem to set the inking successively register to the master signal, and then turn on "in time" of the master signal (ie at the same speed), even if In the meantime, the already registered printing plate cylinders in the "sleeve roll" are again swiveled out of their printing position.

A preferred field of application of the method is the pre-registering, in particular of central cylinder machines. Especially when used as a pre-register method, the method can be combined with other methods that register during the printing operation.

However, register operations according to the invention are also conceivable during ongoing printing operation.

If the images recorded by the sensor station are displayed on a screen, then it is advantageous for the machine operator if the display produces, for example, a linear relationship between a desired position of an image and the image.

Example: The plate cylinder, which was first placed in the print position and printed, continues to be rotated while the register process is on the other pressure plate cylinders is performed. He serves as master. It delivers one trigger signal per revolution. On a screen visible from the control panel of the printing press, stationary images of the printing material and monochrome printed images printed on them are visible. These still images are taken by a sensor station, which is arranged in the direction of the printing material behind the last inking unit, when the trigger signal reports the completion of a rotation of the master cylinder. On the screen is in the form of a sharp line, which runs transversely to the transport direction of the printing substrate, a screen mark visible.

The register process in this example is as follows:

First, a first printing plate cylinder - "master cylinder" - brought into printing position. Its angular position is due to correction signals at

This example causes the operator at the push of a button until it is corrected until the front edge of the monochrome print image of the master cylinder is flush with the screen mark. In the illustrated context, this means that the leading edge of the monochrome image reaches the screen mark when the trigger signal indicates the completion of one revolution of the master cylinder.

Then the master cylinder is turned off from the printing position but further rotated in the parked position. The machine operator adjusts the angular position of the other cylinders one after the other with further correction signals so that, with each recording, that is, with each trigger signal of the master cylinder with its front edge, they also rest against this marking. In this way, the angular positions of all printing plate cylinders are brought into line with that of the master cylinder.

The distance of the print image from the mark is displayed linearly on the screen to facilitate the operator's work.

At the end of this register process, the angular position of all printing plate cylinders is well adjusted to each other.

In view of this example, however, it should be emphasized that often several successive pictures of printed substrate must be taken in order to allow a suitable statement about the misalignment of the respective printing plate cylinder. In this case, the Location information of the individual images, for example, objectified by averaging. In this way, the mentioned still images can be improved.

When visualizing register errors, the simultaneous display of monochrome print images of different inking units can also be useful.

For a machine operator performing the registration, it is particularly advantageous in this case if the print images of different inking units, which have been recorded at different times as mentioned above, are made visible at the same time, which as a rule requires intermediate storage of the images.

Also in this case, it is advisable to represent a target position by a marker and represent deviations from these target positions to scale. This can be done on multiple screens, or on a multi-split screen. It is extremely user-friendly when these different print images are displayed next to each other, with their position in the direction of printing indicating the deviation of their position from a desired position.

Another possibility is that the operator applies markings to the various monochrome print images. It is particularly advantageous if he does so in places of monochrome print images, which he knows that they are superimposed on the multicolored print image. The control device can then calculate the correction signals which ensure that these two markings are printed on the printing substrate web in such a way that they are printed one above the other at a specific angular position of the master cylinder (s). The same can be done without machine operator if a control device sets such markings, or if it uses specific points in the monochrome print images for the described purpose.

It is advantageous if a printing press for carrying out the method according to the invention contains control devices with which a part of the illustrated and claimed methods can be carried out automatically.

A rotary printing press for carrying out the method according to the invention is generally equipped with sensor arrangements which are passed by the printing substrate after the last inking unit arranged on the impression cylinder, since sensor arrangements arranged in this way can receive the print images of all these inking units. Often, the inclusion of two camera systems in such a sensor arrangement is recommended in order to be able to adequately record once the entire print image and on the other hand for registering specific area elements. Often. You should then such camera systems both for hiring according to the document US 6634297 B2 as well as to register according to the present invention. This could be used when hiring over the entire width of the print image, for example, a line scan camera, which can cover the entire print width. A second camera system would then focus on specific, for the purpose of registration suitable image sections - such as brands, crosses or even randomly suitable components of the images.

Further embodiments of the invention will become apparent from the description and the claims.
The figures show: Fig. 1 a functional sketch of a central cylinder flexo printing machine Fig. 2 the functional sketch FIG. 1 in carrying out a register method according to the invention Fig. 3 the functional sketch FIG. 1 in carrying out a register method according to the invention Fig. 4 a schematic representation of a screen image when performing a register method according to the invention Fig. 5 a second schematic representation of a screen image when performing a register method according to the invention Fig. 6 a third schematic representation of a screen image when performing a register method according to the invention

FIG. 1 shows a functional diagram of a central cylinder flexographic printing machine 3 in the execution of a print job to which all six inking units Fn are required. Therefore, all printing plate cylinders D1 to D6 are shown in their printing position.

In the illustrated function sketch of the normal mechanical components of such a machine, only the impression cylinder 2 and the pressure rollers D1 to D6 were shown. The other components are well known to those skilled in the art and partly also in the cited references US 6,634,297 B2 shown. After the printing substrate 1 has been pressed by the guide roller 4 to the central impression cylinder 2, it is 1 passed by the impression cylinder 2 to the pressure cylinders D1 to D6. Here, the web 1 passes through the printing zones DZ1 to DZ6 between the respective printing cylinders D1 to D6 and the impression cylinder 2 to be printed there. Finally, the web 1 leaves the impression cylinder 2 after the last printing unit F6 and passes in its transport direction z the sensor station S. During the transport of the web 1 by the impression cylinder 2, the slip between these elements is negligible. The arrow 5 symbolizes the recording direction of the sensor station S. The point P illustrates the location of the printing material on which on the screen 7 of the FIGS. 4 to 6 the screen mark 8 is located.

FIG. 2 shows the same function sketch at the beginning of an example of a register method according to the invention. Only the printing cylinder D1 is employed to the counter-pressure cylinder 2, and prints the substrate web 1 with a monochrome print image 6. In FIG. 3 the register process has progressed further. The registration has already been carried out on the plate cylinders D1 to D4. These cylinders D1 to D4 were turned off again after their registration by the counter-pressure cylinder 2 and continue to rotate at the same speed. Im in FIG. 3 shown torque prints only the printing plate cylinder D5. The registration of the cylinder D6 is still pending. Suitable sensors on the first registered printing plate cylinder D1 provide a trigger signal at each completed rotation of this cylinder, which causes the sensor assembly S, an image of the printing material web take. The cylinder D1 thus assumes a master function. FIG. 4 shows a schematic representation of an image on the screen 7. In the image, the printing material web 2 with its 2 edges 11 can be seen, which carries the monochrome print images 6a to d. The image has been recorded by the sensor array S before registering.

For this reason, the front edge of the monochrome printed image 6c in the transport direction of the web z is still spaced from the screen mark for the longitudinal register 8. This screen mark corresponds to the illustration of the position of the screen mark P and may well be fixedly mounted on the machine frame.

Visible is also the screen mark to the transverse registers 10. The distance between the lower edge of the print images 6a to d shows here that the cross registers is still pending.

FIG. 5 shows a schematic representation of an image on the screen 7, which illustrates in this embodiment, the completed register process on a printing cylinder characterized in that the lower edges of the images 6a to d abut the screen mark 10 and that the front edge of the printed image 6c flush with the screen mark 8 runs. In the representation of the monochrome print images 6, one will usually be content with a smaller number of print images 6 of an inking unit Fn on a screen. In FIG. 6 a screen 7 is shown, on the same time print images 6 are shown, which come from different inking units. Since these inking units Fn have been printed at different times and have been registered, such a representation requires at least intermediate storage of monochrome print images 6. However, this measure may also be advantageous if such simultaneous display on a screen 7 is not intended at all.

At this point, let's go back to the US 6,634,297 B2 and on parallel applications like the DE 101 45 957 A1 pointed. These documents are concerned with the details of automatic Beistellverfahren in which the printing plate cylinder of a rotary printing machine are hired in an appropriate manner to his or her impression cylinder. The details of these ancillary procedures (such as the evaluation of the light intensity of the by Printed image of reflected light, the observation of this light intensity profile in the provision, the comparison with a digital target image or the registration of a specific intensity curve, etc.), as well as the design of the printing machine for performing this method (equipped with a camera, type of camera, programming the control device etc.) are essential to understanding these lines and are hereby included within the scope of the disclosure of the present invention.

Naturally, the so-called addition process is performed at the beginning of a print job. In the case of a multicolor printing machine, this setting-up process is generally carried out similarly to the register process explained with reference to the figures, in that the individual inking units successively produce monochrome print images which are preferably recorded by a sensor arrangement arranged downstream of the web 2 after the last printing unit Dn. The images 6a-d recorded by the sensor array are examined. On the basis of the investigation, the provisioning process is regulated.

The images obtained in this way can also be used for a register process according to the invention. Therefore, all possible combinations of in the US 6,634,297 B2 described Beistellverfahren and claimed in this document register method considered advantageous.

In addition, the two methods rely on the same or similar hardware components.

It also appears possible in a further embodiment of the method according to the invention instead of the sequential registration of individual printing plate cylinders to register groups of printing plate cylinders. Due to the following considerations, it appears to be advantageous if, in these groups, the number of printing plate cylinders is smaller than the number n of the printing plate cylinders active in the printing process.

Such register processes, in which then monochrome print images but, for example, two-color print images are evaluated, would be faster to perform than due to monochrome print images performed procedures. To This method would advantageously use one or more cameras that can resolve the spectral regions of monochrome print images from one another in a multicolored print image. This appears to be possible in particular due to the reflected light of the areas of the multicolor printed image in which only one color has been applied. In the areas in which two or more printed images have been printed on top of each other, an evaluation of the multicolor printed image appears more difficult. With an eight or ten-color print image, such areas will be harder to find than in a two- or three-color print image.

Under the outlined prerequisites can also be found in the pamphlets US 6,634,297 B2 and DE 101 45 957 A1 Be described due to multicolored printed images. Again, all combinations between the registers or Vorregistern and the additions offer due to multicolored print images. LIST OF REFERENCE NUMBERS 1 printing material 2 Impression cylinder 3 Zentralzylinderflexodruckmaschine 4 deflecting 5 Arrow in the recording direction of the sensor arrangement 6 monochrome print image 7 screen 8th Screen marking for longitudinal registration 9 Subdivision of the screen 10 Screen marking for cross registering 11 Edges of the substrate web dn Printing plate cylinder / forme cylinder of the nth printing unit DZn Printing zone of the nth printing unit S sensor arrangement P Illustration of the position of the screen marker φ Circumferential direction / direction of rotation of the impression cylinder n Number of printing units used to print z Transport direction of the film web

Claims (20)

1. Method for registering a rotary press (3) for a printing process, wherein "n" inking systems (Fn)each produce monochrome printed images (6) and print one on top of the other thereby producing n-coloured printed images, wherein

   - the images (6) of the printed material (1) are shot by at least one sensor station (S),

   - information on the rotary movements of the printing plate cylinders (Dn) is recorded

   - and the images (9) and the information are used to produce correction signals,

   - which actuate the actuators of the printing plate cylinders (Dn) until the deviation of the monochrome images (6) of the respective inking systems (Fn) from a desired position on the material to be printed (1) lies within defined range of tolerance values,
   said registering method being characterized in that

   - during the registering method on printing plate cylinder (Dn) at a time is in the printing position,

   - the at least one sensor station (S) shoots the produced monochrome printed images (6) and

   - the correction signals for the one or more actuators of a printing plate cylinder (Dn) are obtained based on the monochrome image produced by the respective printing plate cylinder (Dn) and the information on the rotary movements of at least one printing plate cylinder (Dn).
2. Method according to claim 1,
   characterized in that
   during the registering method at least one printing plate cylinder (Dn), which is not in the printing position, is driven further.
3. Method according to one of the two preceding claims,
   characterized in that
   the at least one driven printing plate cylinder (Dn), which is not in the printing position, is driven at the same circumferential speed as the cylinder (Dn) that is currently printing.
4. Method according to the preceding claim,
   characterized in that
   the information on the rotary movements of the at least one driven printing plate cylinder (Dn), which is not in the printing position, is used in order to determine the correction signals.
5. Method according to the preceding claim,
   characterized in that
   the information on the rotary movements of a driven printing plate cylinder (Dn), which is not in the printing position, is used in order to determine the correction signals.
6. Method according to the preceding claim,
   characterized in that
   the information on the rotary movements of the printing plate cylinder (Dn), which was first in the printing is used in order to determine the correction signals.
7. Method according to one of the preceding claims,
   characterized in that
   the method is used for pre-registration.
8. Method according to one of the preceding claims,
   characterized in that
   the positions of the different printed images (6) are displayed on the at least one screen (7) in a functional, preferably linear relation to the position, which the printed images had each assumed at the time of a specific angular position of the printing plate cylinders (Dn).
9. Method according to one of the preceding claims,
   characterized in that
   the printed images (6), which are printed by different printing plate cylinders (Dn) on different surface sections of the material to be printed (1), are displayed at the same time on at least one screen (7).
10. Method according to one of the preceding claims,
    characterized in that
    the relative positions of the different printed images (6) in relation to one another are adjusted at least partly, in that a machine operator observes the at least one screen (7) and performs adjustments.
11. Method according to one of the preceding claims,
    characterized in that
    the printed images (6) on different surface sections are displayed on at least one screen (7) together with a screen marking (8, 10), which clarifies the desired position of the printed images (6).
12. Method according to one of the preceding claims,
    characterized in that
    at least two monochrome printed images (6) are displayed on at least one screen (7) and that a machine operator provides points of these printed images (6) with additional markings.
13. Method according to one of the preceding claims,
    characterized in that
    a control device provides additional markings in at least two monochrome images.
14. Method according to one of the preceding claims,
    characterized in that
    the relative position of the different printed images in relation to one another are adjusted at least partly, in that a computing unit recognizes specific patterns in at least one of the printed images (6), compares them to their desired position in the polychrome image and calculates correction signals based on this comparison.
15. Method according to one of the three preceding claims,
    characterized in that
    the control device relates the position of the additional markings and/or the specific patterns in the at least two monochrome images to the information on the rotary movements of printing plate cylinders (Dn),
    that the correction signals are obtained based on the relative deviations of the position of the different markings in relation to one another in the at least two images and the information on the rotary movements of the printing plate cylinders (Dn)
    and that the desired position of the images on the material to be printed is achieved, if the distance of the printed images from the markings lies within a defined range of tolerances.
16. Method according to one of the preceding claims,
    characterized in that
    the desired position is determined based on the position of a printed image (Dn) on the material to be printed.
17. Method according to one of the preceding claims,
    characterized in that
    the registration is based on monochrome printed images (6), which were shot during the additional setting process.
18. Rotary press for implementing a method according to one of the preceding claims.
19. Rotary press according to the preceding claim,
    characterized by
    at least one sensor station (S), which is disposed in the direction of travel (z) of the web of material to be printed (1) downstream of the last inking system (Fn).
20. Rotary press according to the preceding claim,
    characterized by
    a sensor station (S), which comprises two camera systems, the first of which is suitable for scanning the entire printing surface (6) with low resolution and the second of which is suitable for scanning a partial surface with high resolution.

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