EP3820704B1 - Method and device for setting up a circumferential register for a print job in a multi-colour printing press - Google Patents

Description

The invention relates to a method for setting up a circumferential register of a print job in a printing press and a rotary printing press.

From the DE 10 2009 023963 A1 a printing machine for printing a paper web is known, register control being carried out during production using register marks printed on the paper web and sensors designed as mark readers in order to achieve register-accurate printing between the individual printing units of the printing press.

In order to process print jobs in rotary printing machines, in particular in multi-column machines such as inline gravure printing machines, it is necessary to adjust the individual printing cylinders so that they are in register with one another during production. This means that the printing cylinders in the individual printing units must be in a fixed phase relationship to one another. This is the only way to ensure that the print images, which are made up of individual colors that are each printed by a printing cylinder, also have the desired appearance.

In particular at the beginning of a print job, it takes a certain amount of time until the stated phase position is found. Material to be printed is usually also consumed in the process, so that waste occurs. In addition, finding the phase position often requires manual intervention.

The object of the present invention is therefore to propose a method and a rotary printing machine which avoid or at least reduce at least some of the disadvantages mentioned.

According to the invention, this object is achieved by all the features of claim 1. Possible developments of the invention are specified in the dependent claims.

1. a) Einsetzen der Druckzylinder in Druckwerke
2. b) anschließendes Positionieren der Druckzylinder in Umfangsrichtung relativ zum Druckwerksgestell anhand einer an dem Druckzylinder befindlichen Positioniermarke
3. c) anschließendes Drucken einer sich auf dem in Transportrichtung einer Materialbahn gesehen ersten Druckzylinder befindlichen Druckmarke
4. d) anschließendes Abtasten der Druckmarke in zumindest einem zweiten Druckwerk, in welchem der mindestens eine zweite Druckzylinder eingesetzt ist, durch einen Druckmarkensensor
5. e) anschließendes Einstellen des zumindest einen zweiten Druckzylinders in Umfangsrichtung anhand von geometrischen Daten des Druckwerks, welche die

According to the present invention, it is provided that the method according to the invention for setting up a circumferential register of a print job in a multicolor printing press with a first and at least one second printing cylinder comprises the following steps:

1. a) Insertion of the printing cylinders in the printing units
2. b) Subsequent positioning of the printing cylinders in the circumferential direction relative to the printing unit frame using a positioning mark located on the printing cylinder
3. c) Subsequent printing of a print mark located on the first printing cylinder seen in the transport direction of a material web
4. d) subsequent scanning of the print mark in at least one second printing unit, in which the at least one second printing cylinder is used, by a print mark sensor
5. e) subsequent adjustment of the at least one second printing cylinder in the circumferential direction based on geometric data of the printing unit, which the

relative position of the print mark sensor to the printing unit frame, the circumference of the printing cylinder, the angular position of the printing cylinder and the position of the impression cylinder, and the point in time at which the print mark sensor scans the print mark, as well as the web speed of the material web, so that a register mark of the at least one second pressure cylinder in lies in a capture area of the print mark sensor, the at least one second printing unit being in a non-printing arrangement.

In order to start a print job, the printing cylinders provided with the individual print images must first be inserted into the individual printing units. The printing units also include counter-pressure rollers or cylinders over which the web of material runs. Later, the printing cylinder and/or counter-pressure roller are adjusted relative to one another, so that they can be brought from a non-printing arrangement into a printing arrangement in which the printing roller touches the material web and thus transfers ink. Of course, the reverse adjustment option (from printing to non-printing) is also provided.

In a method according to the invention, each pressure cylinder includes a positioning mark with which the pressure cylinder relative to the machine frame of the printing unit can be positioned or is positioned. The positioning mark has a fixed position relative to a printed image of the respective printing cylinder, so that after the positioning of the printing cylinder, the printed image also assumes a fixed position relative to the machine frame. The position of the positioning mark relative to the print image is preferably the same for all printing cylinders of a print job. A positioning sensor is provided to detect the respective positioning mark. After being inserted and connected to a drive, the printing cylinder is preferably rotated at least until the positioning sensor detects the positioning mark. It is advantageous here that no print image has to be generated in order to carry out the step, ie waste is saved. If one relied on the positioning of the individual print images in the printing unit, the observer would notice that even with a known path length of the material web between the printing units, the print is not in register. The reason for this is that a material web can shorten or lengthen due to various influences (temperature, elasticity, web tension), especially during acceleration and deceleration phases. This influence is now at least partially compensated for by the method steps described below.

In a further step, a print mark located on the first printing cylinder, viewed in the direction of transport of a material web, is then printed onto the material web. This print mark is preferably an unambiguous initial print mark that differs from other print marks and is only provided in or on the first impression cylinder of a print job.

In a subsequent step, the material web is now transported through the other printing units, with a print mark sensor scanning this print mark in each additional printing unit that is present. The effective web path between the first impression cylinder and the respective print mark sensor can now be determined from the point in time at which the print mark sensor detects the print mark and from the web speed. Since the print mark sensor is a well-known, or at least simple determinable distance from the printing cylinder, the effective web path between the first printing cylinder and the printing cylinder under consideration, to which the respective printing mark sensor is assigned, can be calculated back. The phasing of the printing cylinder under consideration can now be set accordingly, so that both cylinders then print the print images one on top of the other in the correct register.

The time required to carry out the method according to the invention is essentially limited to the passage of the first print mark through all the printing units.

According to the invention, the at least one second printing unit is in a non-printing arrangement.

In this case, the substrate is not printed, so there is no waste. In this way, the direction of movement of the material web can even be reversed at first in order to be able to guide it backwards. Since the printing units are set in their phase position relative to one another, the material web section that has already passed can be printed. Not only is there no waste, but the material web section that has already been used is immediately recycled. In particular in a serial gravure printing press, the impression cylinder is often moved relative to the impression roller, so that the distance between the impression cylinder and the impression cylinder is also included in the calculation of the effective web path.

In a further advantageous embodiment of the invention, it is provided that the positioning mark is detected optically, magnetically and/or electrically. The positioning sensor is also designed accordingly, ie it can detect an optical contrast and/or a magnetic and/or electric field. The position mark can be arranged on the outer circumference of the printing cylinder or on one of the end faces. In particular, a magnetically and/or electrically recognizable positioning mark is insensitive to contamination, which can be caused by printing ink, for example. This embodiment of the invention naturally also includes corresponding sensors that can detect such position marks, ie an optical sensor, a magnetic sensor and/or an electrical sensor.

In a further advantageous embodiment of the invention, it is provided that the positioning mark comprises at least one of the following components: barcode, QR code, magnet, electronic chip, engraving in the printing cylinder, body raised relative to the surface of the printing cylinder. A barcode or a QR code are optically detectable positioning marks that can be read with an optical scanner. A magnet can be a small body of magnetic material that can be inserted into a bore of the printing cylinder, for example. A simple magnetic sensor is then sufficient to detect this magnet. An electronic chip, on the other hand, can provide an electrical field that can be evaluated with an electronic sensor. In particular, an electronic chip, like a magnet, can be set up to provide additional information about the printing cylinder. Such a chip can in particular be an RFID chip. A positioning mark can also include an engraving in the printing cylinder, which in turn can be recognized by an optical sensor. A body that is raised relative to the surface of the printing cylinder and can be recognized either by an optical sensor or by a sensor that scans the surface of the cylinder is also conceivable. A scanning sensor can be deflected when it hits the body. This deflection can be detected in a suitable manner.

A further preferred embodiment of the invention includes that the current status of the printing press and/or the current status of the method and/or at least one error message is displayed by means of a display device. A display device is, for example, a monitor in the area of the operating unit of the printing press. However, the information can also be displayed on mobile devices that are in data contact with the printing press in some way. In relation to the current status of the method, it can be displayed, for example, how much the method according to the invention will still need to complete.

In a further refinement, it is provided that, in the event of an error message, it is indicated in which printing unit the error occurred and/or what type of error is present. It is thus possible, for example, to indicate to a machine operator when the print mark in a printing unit was not recognized by a print mark sensor. Because on the basis of the machine speed prevailing during the implementation of the method, the point in time at which the Print mark would have to be recognized. However, if the print mark has not been recognized, this indicates an error. The same applies if a following print mark sensor has already recognized the print mark. An error message can mean, for example, that a print mark sensor has a defect and/or is incorrectly positioned in relation to the printing cylinder. A list of various causes that need to be checked can also be displayed to the machine operator. This ensures that the print job is completed completely and, above all, in the desired quality.

The method described above can be used particularly advantageously if a plastic web is printed with the print job. A plastic web has a high level of elasticity, which can even depend on the temperature. This prevents printing from starting directly when the printing cylinders are positioned based on the positioning marks. The method according to the invention thus offers particular advantages in combination with a plastic web.

• einem ersten und zumindest einem zweiten Druckzylinder,
• einem ersten und zumindest einem zweiten Druckwerk, in welches der jeweilige Druckzylinder einsetzbar ist,
• wobei mit dem in Transportrichtung einer Materialbahn gesehen ersten Druckzylinder eine Druckmarke auf die Materialbahn druckbar ist,
• einem Druckmarkensensor in dem zumindest einem zweiten Druckwerk zum Abtasten von auf der Materialbahn aufgedruckten Druckmarken
• einem Positioniersensor in jedem Druckwerk zum Abtasten einer Positioniermarke eines Druckzylinders, wobei sich die Positioniermarke auf dem Außenumfang oder auf einer der Stirnseiten des Druckzylinders befindet,
• einer Auswerte- und Steuereinrichtung, mit welcher Daten des Druckmarkensensors und/ der Positioniersensoren empfangbar und mit welcher Antriebe der Druckzylinder zum Einstellen der Umfangspositionen der Druckzylinder ansteuerbar sind, wobei das zumindest eine zweite Druckwerk in eine nicht druckenden Anordnung haltbar ist.

The object mentioned at the outset is also achieved by all the features of claim 8, namely by a multi-color printing machine for carrying out a method according to one of claims 1 to 7 with

• a first and at least a second pressure cylinder,
• a first and at least a second printing unit, in which the respective printing cylinder can be inserted,
• wherein a print mark can be printed on the material web with the first printing cylinder seen in the transport direction of a material web,
• a print mark sensor in the at least one second printing unit for scanning print marks printed on the material web
• a positioning sensor in each printing unit for scanning a positioning mark of a printing cylinder, the positioning mark being located on the outer circumference or on one of the end faces of the printing cylinder,
• an evaluation and control device with which data from the print mark sensor and/or the positioning sensors can be received and with which drives of the printing cylinders can be controlled to adjust the circumferential positions of the printing cylinders, with the at least one second printing unit being able to be held in a non-printing arrangement.

This achieves the same advantages that have already been described in connection with the method according to the invention.

Further advantages, features and details of the invention emerge from the following description, in which various exemplary embodiments are explained in detail with reference to the figures.

Fig. 1

Schematische Darstellung einer Druckmaschine nach dem Einsetzen der Druckzylinder

Fig. 2

Schematische Darstellung einer Druckmaschine nach der Positionierung der Druckzylinder anhand von Positioniermarken

Fig. 3

Schematische Darstellung einer Druckmaschine nach der registerhaltigen der Druckzylinder in Umfangsrichtung

The individual figures show:

1

Schematic representation of a printing machine after inserting the printing cylinders

2

Schematic representation of a printing machine after the positioning of the printing cylinder using positioning marks

3

Schematic representation of a printing machine after registering the printing cylinders in the circumferential direction

The figures show schematic representations of a printing machine for carrying out the method according to the invention. In the figure 1 the printing machine 100 can be seen. This initially includes an unwinding device 101 with which a material web 102 is made available. This is fed to the individual printing units 110, 120, 130 via various rollers 103, which can be, for example, transport, deflection, spreader rollers or even entire roller units, such as those used in drying devices. Seen in the transport direction T of the material web, the printing unit 110 is the first printing unit which has special properties which will be discussed further below. It three printing units can be seen, but a printing machine according to the invention can of course include any number of printing units. However, it is also possible that in a method according to the invention not all existing printing units are used because the colors available in a printing press are not necessary for every print job.

Each printing unit includes an impression cylinder 111, 121, 131 and an impression cylinder 112, 122, 132. The material web 102 is guided over the impression cylinder in order to be printed here by the impression cylinder. In the exemplary embodiment shown, the printing units are gravure printing units of a serial gravure printing press. In such a machine, the printing cylinders generally remain stationary in the printing unit frame (not shown) when a print job is being processed, while the impression cylinders can be displaced relative to the printing cylinders, often in a vertical direction, in order to bring the material web into or out of contact with the printing cylinders.

After printing, the material web is generally fed to a winding device 141, in which it is wound back into rolls for easier transport.

In the figure 1 it can now be seen that the pressure cylinders have already been inserted into the respective printing units. The printing cylinders are now positioned using positioning marks 113, 123, 133, which can be detected by positioning sensors 114, 124, 134, which are preferably arranged in a stationary manner in the respective printing unit. In the figure 1 It is shown on the basis of printing units 110 and 120 that the positioning marks have already been recognized (positioning mark and positioning sensor are directly opposite one another), whereas this is not yet the case for printing unit 130. After this has been done for all printing cylinders, the angular positions of the individual printing cylinders are fixed relative to the respective printing unit frames. However, it is also possible to specify the locations of the position marks relative to a zero line of the printing cylinder and to take this specification into account when applying the printed image to the printing cylinder. Instead of detection of the position mark by positioning sensors, these values can also be determined by manual measurement and then made accessible to an evaluation and control device. The zero line of a printing cylinder is a quantity which has a predetermined or fixed relationship to the machine frame and relative to which the angular position of the printing cylinder relative to the machine frame can be specified.

In the figure 2 it can now be seen that all the printing cylinders are now aligned relative to the respective printing couple frame. Furthermore, the impression cylinder 112 of the first printing unit 110 is lowered in order to bring the material web 102 into contact with the impression cylinder. In addition, it can be seen that the printing cylinder 111 carries a printing mark 115, which is designed as a depression, for example, in gravure printing. This print mark 115 has already been applied to the material web as a print mark imprint 150 . When material web 102 is transported, print mark imprint 150 runs through all printing units and thus runs past print mark sensors 115, 125, 135, which preferably scan the material web continuously and, when printed mark imprint 150 is detected, sends a signal to an evaluation and control device (not shown). Based on the transport speed of the material web and the time at which the print mark imprint passes the respective print mark sensor, this can calculate the effective path that the material web has taken either from the time the print mark print is printed and/or from the time the print mark print is recognized by the print mark sensor of one of the previous printing units has traveled up to the time of recognition by the print mark sensor in the printing unit under consideration. Since the print mark sensors also have defined positions relative to the respective printing unit frame, the evaluation and control unit can now, taking into account the geometric data of the printing unit, in particular the circumference of the printing cylinder, which include the installation position of the printing cylinder, the position of the impression cylinder at the time the Print mark imprint (especially if it is not employed on the printing cylinder) and the angular position of the printing cylinder now include the angular position by means of a control signal of the printing cylinder so that the print images of each cylinder correspond to those of the other cylinders, in which case register-keeping printing is made possible.

This situation is caused by the figure 3 clearly, in which all printing units are now in the printing position and the print job can be processed. The print mark sensors 115, 125 and 135 now work in a known manner as register sensors, which scan register marks that are not shown but are also printed and forward them to the evaluation and control unit, which sends control signals to the printing cylinders in the event of deviations. A known register control is thus implemented.

The reference symbols that have been explained with reference to one figure are generally not shown in the other figures in order to maintain clarity. However, the same reference numbers are assigned to the same features. Reference List 100 printing press 101 unwinding device 102 web of material 103 roller 110 printing unit 111 pressure cylinder 112 Impression cylinder 113 positioning marks 114 positioning sensor 115 print mark 120 printing unit 121 pressure cylinder 122 Impression cylinder 123 positioning marks 124 positioning sensor 125 print mark 130 printing unit 131 pressure cylinder 132 Impression cylinder 133 positioning marks 134 positioning sensor 135 print mark 141 unwinding device 150 Print mark imprint T transport direction

Claims (8)

1. A method for setting up a circumferential register for a print job in a multi-color printing press (100) having a first and at least one second printing cylinder (111, 121, 131), wherein the method comprises the following steps:

   a) insertion of the printing cylinders (111, 121, 131) into printing units (110, 120, 130)

   b) subsequent positioning of the printing cylinders in the circumferential direction relative to the printing unit frame on the basis of a positioning mark (113, 123, 133) located on the printing cylinder

   c) subsequent printing of a print mark (115) located on the first printing cylinder (111) seen in the transport direction of a material web (102)

   d) subsequent scanning of the print mark in at least a second printing unit, in which the at least one second printing cylinder (121, 131) is inserted, by means of the print mark sensor (125, 135)

   e) subsequent setting of the at least one second printing cylinder (121, 131) in the circumferential direction on the basis of geometric data of the printing unit, which data comprise the relative position of the print mark sensor to the printing unit frame, the circumference of the printing cylinder, the angular position of the printing cylinder and the position of the impression cylinder (122, 132), and the point in time, at which the printing mark sensor scans the print mark (115), as well as the web speed of the material web, so that a register mark of the at least one second printing cylinder (121, 131) is in the capture range of the print mark sensor, wherein the at least one second printing unit is located in a non-printing arrangement.
2. The method according to the preceding claim,
   characterized in that
   step b) is carried out with the aid of a positioning sensor, with which the positioning mark is scanned.
3. The method according to any one of the preceding claims,
   characterized in that
   the positioning mark can be detected, optically, magnetically and/or electrically.
4. The method according to any one of the preceding claims,
   characterized in that
   the positioning mark comprises at least one of the following components:

   • Barcode

   • QR code

   • Magnet

   • Electronic chip

   • Engraving in the printing cylinder

   • Body raised above the surface of the printing cylinder.
5. The method according to any one of the preceding claims,
   characterized in that
   the current status of the printing press and/or the current status of the process and/or at least an error message is shown by means of a display device.
6. The method according to any one of the preceding claims,
   characterized in that
   in the event of an error message it is displayed, in which printing unit the error has occurred and/or what type of error is present.
7. The method according to the preceding claim,
   characterized in that
   a plastic web is printed with the print job.
8. A multi-color printing press for carrying out a method according to any one of claims 1 to 7 having

   - a first and at least one second printing cylinder (111, 121, 131),

   - a first and at least one second printing unit (110, 120, 130), into which the respective printing cylinder can be inserted,

   - wherein with the first printing cylinder (111) seen in the transport direction of a material web (102) a print mark (115) can be printed on the material web,

   - a print mark sensor (125, 135) in the at least one second printing unit (120, 130) for scanning print marks imprinted on the material web (102),

   - a positioning sensor (114, 124, 134) in each printing unit for scanning a positioning mark (113, 123, 133) of a printing cylinder, wherein the positioning mark is located on the outer circumference or on one of the end faces of the printing cylinder,

   - an evaluation and control device, with which data from the print mark sensor (115, 125, 135) and/or the positioning sensors (114, 124, 134) can be received and with which drives of the printing cylinders for setting the circumferential position of the printing cylinder can be controlled, wherein the at least one second printing unit (120, 130) can be maintained in a non-printing arrangement.

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