EP2368710B1 - Method for changing printing plates in a printing press with multiple printing units - Google Patents

Description

The present invention relates to a method for changing printing plates in rotary printing machines with multiple printing units. These may be sheet or web presses.

There are already a whole series of different fully and semi-automatic methods known, according to which the printing plates of offset printing presses are changed. In printing machines in which both the plate cylinder and the blanket cylinder of the printing units are always geared to the main drive of the printing press, the plates are successively successively from the printing unit after opening the slide rails because of the different phase angles of the plate cylinder relative to the machine angle in the individual printing units conveyed out, removed after conveying out and the new plates again successively fed into the printing units. In recent years, however, printing presses have become known in which the plate cylinder own drives, of which they can be rotated independently of the machine drive and thus relative to the blanket cylinder, optionally at conversion or set-up on the machine after the respective plate cylinder was uncoupled from the main drive of the machine by a clutch. Such a printing press is eg from the WO 0224454 A1 known. Another such printing press is for example in the DE 10 2008 030 438 A1 described. When changing plates, the plates are indeed conveyed out of the printing units there in succession in the engaged state of the plate cylinder from the main drive. Thereafter, however, the plate cylinders are stopped by the blanket cylinders and uncoupled from the main drive of the machine. The collection of the new plates is then done in such a way that the plate cylinder pull through their auxiliary drive all printing plates simultaneously. In addition, it is z. B. from the WO 2006/018105 A2 Also known, the entire plate change process so the out and the re-promoting the printing plates alone by the drives of the plate cylinder make while at the same time from the machine drive otherwise moving blanket cylinder in the respective printing unit z. B. undergoes a washing process.

Disturbances can now occur in the course of a plate changing process in that, for example, the printing plate is tilted in a printing unit as it is being conveyed out, the electromechanically actuated clamping strip does not open, the sensors for detecting the plate edge or the plate end report errors, etc. Therefore, operating modes have also already been developed. to complete the plate changing process as effectively as possible in such a disturbance. For this the beats EP 1 348 551 B1 before, after detecting the fault, disengage the plate cylinder in the faulty printing unit once from the drive and completely complete the change process for the other printing units, before then the fault is eliminated then the plate is changed in the faulty printing unit.

As you can easily see the total time required for this process is not minimal, since the plate change for the faulty printing unit is carried out separately and not coincide partially with the change process for the other undisturbed printing units. It is, however, z. B. from the DE 196 36 703 A1 It is also known to stop the drives of all printing units when a fault occurs during the plate changing operation, to eliminate the disturbance and then to continue the changing process for all printing units ( DE 196 36 703 A1 ). However, this is not always possible in many cases depending on the nature of the disorder. So it may be necessary to rotate the plate cylinder in the faulty printing unit once in a certain position, for example, to be able to solve by hand the slide rails and later to turn the plate cylinder in a specific reference position or turn back to eject the plate. If then the cylinders run along in the other printing units, while there the clamping rails are already released, the printing plates in these works as a result of possibly repeated forward and backward run in the printing units abut / jam, etc.

Problems also occur when the disengaged plate cylinder with the plate thereon for the purpose of conveying out of the printing unit backwards is rotated while the z. B. geared to the main drive of the machine coupled plate cylinder stands still or performs an opposite movement. Because if the disc released from the clamping plate when conveying out due to the small distance to the blanket cylinder with this in contact, the plate may bend and then with more or less probability, depending on the spatial conditions in the printing unit, the presence of special guides, etc. the It is therefore the object of the present invention, in a plate changing method of the type mentioned above to make them so that the plates in the operating modes in which the conveying out of the Plates from the printing unit by the separately driven, disengaged plate cylinder takes place, so for example in case of failure, as safe as possible. This object is achieved with the features specified in claim 1.

According to the invention, in conveying out one or more printing plates by the disengaged plate cylinder of the respective blanket cylinder is moved at a slightly higher peripheral speed than the associated plate cylinder, wherein the difference in the amount of peripheral speeds of plate cylinder and blanket cylinder or between printing plate and blanket at least 0.1 percent , but not more than 10 percent. This has the consequence that the pressure plate, if it comes during the ejection movement with the blanket cylinder in contact, is not compressed, but at best "pulled straight" by the slightly higher peripheral speed of the blanket. In this way, she always safely finds her way back to the holding position on the protection of the printing unit. So now if, for example, in the mode for processing a fault, the plate cylinder in the faulty printing unit, the plate after eliminating the disturbance from the printing unit out after the plate change for the undisturbed printing units is already complete and there is no need, the machine drive with all of them To move driven blanket cylinders, you would expediently turn on the machine drive according to the method of the invention at the same time to allow the blanket cylinder rotate tangentially in the same direction with a slightly higher peripheral speed, in which the plate is conveyed away. Of course, the same measure can also be taken if, before or after the elimination of the disturbance, the plate cylinders move the printing plates out of the no or no longer disturbed printing units, as well in plate change processes in which the removal is always carried out by the plate cylinder in the parked and uncoupled from the main drive of the machine state.

Particularly fast is the inventive method for changing printing plates in case of failure, as provided in claim 4 when a fault occurs in a printing unit, the plate cylinders are disengaged in the non-disturbed printing units, the respective blanket cylinder in these printing units with a slightly higher speed than the plate cylinders are moved while continuing the ejecting operation and at the same time as described in claim 6 and the plate cylinder of the defective printing unit is disengaged and there the plate cylinder is moved to the position in which the disorder can be eliminated, for example, the position in which Screws of the plate clamping rail can be opened manually, or moves the plate cylinder of the faulty printing unit in a reference position. In general, it is advantageous if the fault is eliminated before new printing plates are clamped in the undisturbed printing units. In that case, namely after the ejection of the plate in the faulty printing unit in all printing units of the machine, the plates are retracted simultaneously and synchronously. Further advantages of the invention will become apparent from the following description of exemplary embodiments with reference to FIG FIGS. 1 to 3 of the accompanying drawings.

The FIG. 1 shows a Bogenoffsetrotationsdruckmaschine 30 with multiple printing units in a row construction, of which three printing units 1, 2, 3 are shown. Each of the printing units 1, 2, 3 has an inking unit 25, which transfers the ink to a spanned in printing operation on a plate cylinder 23 printing plate with the printed image. From the printing plate on the plate cylinder 23, the printed image is transferred via a blanket cylinder 22 to a substrate 31, which is printed in the nip between blanket cylinder 22 and impression cylinder 26. Between the printing units 1, 2, 3, the printing materials 31 are moved by means of transport cylinders 24. The impression cylinder 26 and transport cylinder 24 and the blanket cylinder 22 are mechanically connected to each other via a gear train and are driven by a main drive motor 5. During the printing operation are over the Gear train and the plate cylinder 23 in the printing units 1, 2, 3 driven by the here schematically drawn couplings 29 between the plate cylinders 23 and the blanket cylinders 22 are closed. If a print job change is pending, so new plates 6 must be mounted with the new color separations on the plate cylinders 23 and the old printing plates 7 are removed. For this purpose, the printing units 1, 2, 3 each have a plate changer 17 on the left side, which accommodates the old printing plate 7 and provides the new printing plate 6. During the printing plate change, moreover, the plate cylinders 23 can be disengaged and driven independently of the other cylinders 22, 24, 26 by means of their own drive motor 4 (auxiliary drive). The control of the main drive motor 5 and the separate drive motors 4 of the auxiliary drives is done via a machine control, not shown, with a corresponding control computer. In FIG. 1 are the three printing units 1, 2, 3 in different positions during the plate change. In printing unit 3, the plate trailing edge of the old printing plate 7 is just released, so that the old printing plate 7 can be conveyed out. In printing unit 2, the old printing plate 7 was pushed by the backward plate cylinder 23 out in the disc changer 17. In printing unit 1, the old printing plate 7 has been completely pushed out of the printing unit 1 and in the disc changer 17 in a position in which the new plate can be clamped.

In FIG. 2 is fragmentary, the printing unit 3 shown. It can be seen that the plate changer 17 has a lower plate guide element 8 and an upper plate guide element 9. In the lower plate guide element 8 is a pivotable guide element 10, which is intended to remove the old pressure plate 7 via rollers from the plate cylinder 23. The plate changer 17 itself is mechanically stored so that it can be easily lifted and lowered again by the operating personnel by gas pressure springs or other aids. The disc changer 17 also carries a sensor 27, with the correct removal of the old plate 7 can be determined. On the outside of the disk changer 17 are guide elements with rollers in which the new pressure plate 6 is mounted receptive. To remove the old pressure plate 7, the guide element 10 is pivoted toward the plate cylinder 23, so that the old pressure plate 7 on the rollers of the guide element 10 out can slide. To feed out the old pressure plate 7, the plate clamping device is opened at the trailing edge 12 on the plate cylinder 23, so that the old pressure plate 7 solves due to their rigidity from the plate cylinder 23 and can slide on the rollers of the pivotable guide element 10 out. The feeding out of the old pressure plate 7 is usually done when employed on the plate cylinder 23 blanket cylinder 22, so that the old pressure plate 7 is conveyed in the gap between the blanket cylinder 22 and plate cylinder 23 in the direction of the pivotable guide element 10. On the pivotable guide element 10, a further sensor 28 is mounted. With this plate sensor 28, the machine control is informed whether the old pressure plate 7 has actually detached from the plate cylinder 23 and is not tilted for any reason. During the trouble-free feeding out of the old printing plate 7 blanket cylinder 22 and plate cylinder 23 are mechanically coupled together and are driven by the continuous gear train on the main drive motor 5. The plate cylinder 23 moves in the direction of arrow, so that the old printing plate 7 is required in the disc changer 17.

The picture in FIG. 3 shows an enlargement of the area around the plate cylinder 23 in the printing unit 3. In FIG. 3 is to recognize the open plate clamping device 12 for the plate trailing edge, which allows the feeding out of the old printing plate 7. By contrast, the plate clamping device 13 for the front edge on the plate cylinder 23 remains closed until the old pressure plate 7 has passed the gap between blanket cylinder 22 and plate cylinder 23. In FIG. 3 In addition, a pressing element 16 can be seen, which is later required when clamping the new printing plate 6.

In FIG. 4 the old pressure plate 7 has been conveyed out of the plate cylinder 23, so that only the plate clamping device for the front edge 13 has to be opened. This end position of the pushed out old pressure plate 7 can also be detected by the sensor 27. At the latest when this end position is reached, the control computer opens the mechanical clutch 29 between plate cylinder 23 and blanket cylinder 22 and disconnects the two cylinders from each other. Alternatively, the clutch 29 can be opened already when the clamping device 12 the Blanket cylinder 22 has happened. From this point on, the plate cylinder 23 is driven only via its associated separate drive motor 4. Thus, the plate cylinder 23 is then driven independently of the other cylinders 22, 24, 26 in the gear train. As soon as the plate cylinder 23 is uncoupled from the blanket cylinder 22, the provision between plate cylinder 23 and blanket cylinder 22 is opened, so that the two cylinders no longer touch. The process described by way of example for the printing unit 3 is then carried out on the other printing units 1 and 2 if there are no faults or error messages. Furthermore, in FIG. 4 to recognize a disk changer 11 located on the disk changer 17. This plate clamping device 11 is designed so that the old pressure plate 7 can be pushed only in one direction upwards, so that the old pressure plate 7 can not slip back again. This reliably prevents unintentional slipping back in the direction of the plate cylinder 23. This plate clamping device 11 consists of a pinch roller 11.1, a clamping surface 11.2 and a guide track 11.3. When feeding out the old pressure plate 7, the pinch roller 11.1 is pushed along the guideway 11.3 upwards. By its own weight or additional support in the form of a spring force, the roller 11.3 clamps the old pressure plate 7 relative to the clamping surface 11.2, so that slipping back is reliably prevented. As a result, the old pressure plate 7 can only move upwards.

However, if there is a malfunction in a printing unit, for example in the printing unit 3, then the control of the printing press changes to a mode for rectifying this fault and, once, stops the main drive 5 of the machine. Subsequently, the faulty printing unit 3 goes to "pressure from", ie the blanket cylinder 22 is turned off by the plate cylinder 23, ie shifted by not shown pneumatic actuated eccentric by Δ _Z of about 0.5 millimeters in the dot-dash line position ( Fig. 3 ). At the same time, the coupling 29 opens and thus interrupts the power flow between the plate cylinder 23 and the main drive 5 in the printing unit third

The fault may be, for example, that the clamping rail of the plate clamping device 12 has not opened for the trailing edge of the pressure plate 7, which detected by the sensor 28 and reported by a corresponding signal of the control of the machine. In this case, the plate cylinder 23 is moved by the drive motor 4 of its auxiliary drive in the position in which the screws of the clamping rail can be opened manually. This is done by the operator and thus suppresses the printing unit.

Subsequently, the operator presses the button for the continued operation of the drive and the non-malfunctioning printing units, for. B. 2 and 3, continue the ejection of the old printing plate 7 as described above. During this time, the motor 4 of the auxiliary drive rotates the coupled plate cylinder 23 in the currently suppressed printing unit until the end of the plate 7 has reached the sensor 28.

The positioning movement of the plate cylinder takes place in the forward direction, while the blanket cylinder 22 either stands still or rotates backwards. In this way, it is ensured that the loose trailing edge of the plate 7 can nowhere abut in the printing unit and can thereby bend. Now that the plates are stretched in the undisturbed printing units 2 and 3, the main drive 5 rotates in a position in which the printing units 1 and 2 are synchronous to the position occupied by the plate cylinder 23 in the currently suppressed printing unit 3. There, the clutch 29 between plate cylinder 23 and main drive 5 is still open. To eject now the plate 7 in the printing unit 1, the plate cylinder 23 is now rotated by the drive motor 4 of its auxiliary drive backwards, at the same time the main drive 5 rotates the machine and thus the blanket cylinder 22 in the printing unit 1 also backwards, but with a slightly increased speed. The difference δ _V between the peripheral speed V _PL of the plate cylinder 23 and the peripheral speed V _GZ of the blanket cylinder 22 is at least 0.1% and at most 10% and preferably between 0.5 and 10% of the amount of speed. In this way it is ensured that the pressure plate 7, the trailing edge is indeed dissolved, not bulged or bent by accidental contact with the surface of the blanket on the blanket cylinder 22, because the slightly higher peripheral speed of the blanket cylinder 22 exercises in the case a train on the plate 7, which is still clamped by the clamping rail 13 with its front edge.

When the plate 7 is then ejected in the printing unit 1 in the disc changer 17 and the drive 4 stops for the currently suppressed printing unit 3 and the operator can remove the ejected plate. Now, the operator can create the side mounted on the disc changer 17 new printing plate 6 in all printing on the register pins in the disc clamping device 13 for the leading edge of the plate 6 or the system can be done in an alternative variant by an automatic feed of the plate.

Subsequently, the new printing plates 6 can be retracted synchronously in all printing units together. For this purpose, all the plate cylinder as described above by opening the mechanical clutches 29 separated from the other cylinders 22, 24, 26 in the gear train and also the Beistellung between the plate cylinders 23 and the blanket cylinders 22 in the non-disturbed printing units 1 and 2 in the position "pressure from "open. If the new pressure plate 6 is correctly applied, the plate clamping device is closed at the leading edge 13 and the control computer triggers the disc tray. In this case, all the plate cylinder 23 rotate in the printing units 1, 2 and 3 driven by the motor 4 of their auxiliary drives slowly forward, because the new printing plates 6 on the "ironing" rollers 15 are pressed to their respective plate cylinder 23. After complete insertion of the new printing plates 6, the trailing edge of the printing plates is pushed by means of the pressing member 16 in the plate clamping device for the trailing edge 12 so that the plate clamping device 12 can close and the plate is securely locked at the trailing edge. The engagement of the plate cylinder 23 in the mechanical gear train is then made automatically by the control computer of the printing press 30. So then the plate changing process is done.

In the present embodiment, it was described that the undisturbed printing units 1 and 2 terminate their ejection of the old printing plate 7 in such a way that disengages the plate cylinder in the faulty printing unit, and the other printing their ejection in the coupled state only continue when the disturbance in faulty printing unit is manually removed. Here, however, other processes are possible. So it may be useful if, when a fault occurs, for. B. again in the printing unit 3, once all printing units are turned off and go to "pressure off" and are separated via the couplings 29 from the main drive 5 and the gear train of the machine. Then all non-faulty printing units, z. B. continue their ejection by the plate cylinder 23 are moved backwards by the motors 4 of their auxiliary drives. Meanwhile, the machine also rotates the blanket cylinders 22 backwards, again at a slightly higher peripheral speed, to avoid bulging of the pressure plates 7 as described above in accidental contact with the blanket cylinder. Only then, when all the printing plates are inserted into the non-disturbed printing units 1 and 2 in the respective disc changer 17, stop both the main drive 5 and the motors 4 of the auxiliary drives and the faulty printing unit 3 is then manually suppressed by the operator and can, after its pressure plate is removed, make the plate feeder synchronized with the other non-disturbed printing units.

As a further alternative, it is also possible to carry out the plate changing operation in the undisturbed printing units completely with the insertion of the new plates, before the manual suppression in the faulty printing unit.

In all cases, however, when in a printing unit, the plate cylinder 23 rotates backwards with entklemmter trailing edge, at the same time the blanket cylinder 22 is rotated at a slightly higher peripheral speed also backwards.

LIST OF REFERENCE NUMBERS

1

first printing unit

2

second printing unit

3

third printing unit

4

Drive motors (auxiliary drive)

5

Main drive motor

6

new printing plate

7

old printing plate

8th

lower plate guide element

9

upper plate guide element

10

swiveling guide element

11

Disc clamper

11.1

pinch roller

11.2

clamping surface

11.3

guideway

12

Plate clamping device trailing edge

13

Plate clamping device leading edge

14

guard

15

Aufbügelwalze

16

pressing element

17

record changer

22

Blanket cylinder

23

plate cylinder

24

transport cylinder

25

inking

26

Impression cylinder

27

sensor

28

Plate sensor trailing edge

29

clutch

30

press

31

bow

Claims (12)

1. Method for changing printing plates (6, 7) in rotary printing presses including multiple printing units in which the plate cylinders (23) have a drive (4) of their own by means of which they are drivable independently of the associated blanket cylinder (22) in the respective printing unit (1, 2, 3),
   characterized in
   that during the plate changing process, at least in one mode of operation, when one or more printing plates (7) are conveyed out of the printing unit (3), the respective blanket cylinder (22) is moved at a slightly higher circumferential speed (V_GZ) than the associated plate cylinder (23), wherein the difference between the values of the circumferential speeds (V_PL and V_GZ) of the plate cylinder (23) and of the blanket cylinder (22) or between the printing plate and the blanket amounts to 0.1 per cent at the minimum and to 10 per cent at the maximum.
2. Method according to Claim 1,
   wherein the mode of operation is the mode for dealing with a malfunction and wherein at least the blanket cylinder (22) of the printing unit (3) in which the malfunction occurs or has occurred is rotated at the higher circumferential speed (V_GZ).
3. Method according to Claim 1,
   wherein the mode of operation is the mode for dealing with a malfunction and wherein multiple blanket cylinders (22) that are mechanically coupled to each other are simultaneously moved at a slightly higher circumferential speed (V_GZ) than the associated plate cylinders (23).
4. Method according to any one of Claims 1 to 3,
   wherein the mode of operation is a malfunction and, after the malfunction has occurred, the plates in the non-malfunctioning printing units (1, 2) continue to be conveyed out, wherein the respective blanket cylinders (22) of these printing units are moved at the slightly higher speed (V_GZ) than the associated plate cylinders (23), and wherein the malfunction in the malfunctioning printing unit (3) is subsequently eliminated and the plate (7) there is conveyed out, and subsequently the plate insertion is carried out in synchronism or simultaneously for all printing units (1, 2, 3).
5. Method according to any one of Claims 1 to 3,
   wherein the mode of operation is a malfunction and, after the malfunction has occurred, firstly the plate changing progress in the non-malfunctioning printing units is completed, wherein new printing plates (6) are conveyed into the printing units (1, 2) and attached to the plate cylinders (23), and subsequently the malfunction in the malfunctioning printing unit (23) is eliminated, wherein in the process of conveying out the printing plate (7), the blanket cylinder (22) in the malfunctioning printing unit (3) is moved at a slightly higher speed (V_GZ) than the plate cylinder (23).
6. Method according to any one of Claims 2 to 5,
   wherein in the process of eliminating the malfunction, the plate cylinder (23) of the malfunctioning printing unit (3) is uncoupled and moved into the position in which the means of attachment (12) that hold the plate (7) on the cylinder (23) are accessible, and subsequently the means of attachment (12) are manually released.
7. Method according to any one of Claims 2 to 6,
   wherein in the process of eliminating the malfunction, the plate cylinder (23) of the malfunctioning printing unit is uncoupled and rotated into a reference position while at the same time the plates in the non-malfunctioning printing units (1, 2) are moved out and subsequently, with the plate cylinder (23) in the malfunctioning printing unit still uncoupled, the plate cylinders (23) of the other printing units (1, 2) are rotated into a position that is synchronized with the reference position of the plate cylinder (23) in the malfunctioning printing unit (3).
8. Method according to Claim 7,
   wherein the printing plate (7) in the malfunctioning printing unit (3) is subsequently conveyed out while at the same time the blanket cylinders (22) connected to the machine drive (15) in all printing units (1, 2, 3) are rotated backwards at a slightly higher circumferential speed (V_GZ).
9. Method according to any one of Claims 6 to 8,
   wherein once the printing plates (23) in the non-malfunctioning printing units (1, 2) have been conveyed out, the malfunction in the malfunctioning printing unit (3) has been eliminated and the plate (7) has been conveyed out of the malfunctioning printing unit (3), new plates (6) are supplied to all printing units, and wherein in the process of introducing the new plates (6), the plate cylinders (23) of all printing units (1, 2, 3) are uncoupled and the new plates are conveyed into the respective printing units in synchronism, the auxiliary drives (4) associated with the plate cylinders rotating all plate cylinders (23) simultaneously.
10. Printing press including multiple printing units,
    wherein each printing unit (1-3) includes a plate cylinder (23) and a blanket cylinder (22), which is couplable to the machine drive (5), whereas the plate cylinder (23) has its own drive (4) by means of which it is drivable independently of the associated blanket cylinder (22), as well as a control for actuating the drives for the blanket cylinders and the plate cylinders in accordance with different modes of operation,
    characterized in
    that during the plate changing process, at least in one mode of operation, the control programme rotates the respective blanket cylinder(s) at a slightly higher circumferential speed (V_GZ) than an associated plate cylinder (23), and that the difference between the amounts of the circumferential speeds (V_PL and V_GZ) of the plate cylinder (23) and of the blanket cylinder (22) or between the printing plate and the blanket amounts to 0.1 per cent at the minimum and to 10 per cent at the maximum.
11. Control for rotary printing presses including multiple printing units according to Claim 10, in which the plate cylinders (23) have their own drive (4) by means of which the plate cylinders (23) are drivable independently of the associated blanket cylinder (22) in the printing units,
    characterized in
    that in the plate change mode of operation, at least when a malfunction message occurs, to convey one or more printing plates (7) out of the printing unit (3), the control controls the drives (4 and 5) of plate cylinder (23) and blanket cylinder (22) in at least one printing unit in such a way that the blanket cylinder (22) rotates at a slightly higher circumferential speed (V_GZ) than the associated plate cylinder (22).
12. Control according to Claim 11,
    wherein the difference between the amounts of the circumferential speeds (V_PL and V_GZ) of the plate cylinder (23) and of the blanket cylinder (22) or between the printing plate and the blanket amounts to 0.1 per cent at the minimum and to 10 per cent at the maximum.

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