JPH03286865A - Press plate change method - Google Patents

Abstract

PURPOSE:To reduce the time for changing a press plate totally by starting the discharge of an old plate installed on a second plate cylinder, for example, when the second plate cylinder coincides with a position of the discharging plate in the discharging process of the old plate installed on a first plate cylinder. CONSTITUTION:In a press plate change method wherein an old plate installed on the circumferential surface with respect to first - Nth plate cylinders rotating with interlock is to be changed to a new plate, the first plate cylinder 1-11 is made to coincide with a discharging position thereof, and discharging of the old plate is performed by rotating with interlock the first - Nth plate cylinders in the direction of reverse rotation. Thus, the discharging operation of the old plates are performed in sequence of plate cylinders coinciding with the discharging positions thereof during the interlocking rotation of the first - Nth plate cylinders. On the other hand, a last plate cylinder of which an old plate is discharged is made to coincide with a position of a charging plate thereof and charging of a new plate is performed by rotating with interlock the first - Nth plate cylinders in the forward direction. Thus, the charging of the new plates is performed in sequence of plate cylinders coinciding with the charging positions during the interlocking rotation of the first - Nth plate cylinders.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention provides a printing plate exchange method for replacing an old plate attached to the circumferential surface of first to Nth plate cylinders that rotate in conjunction with a new plate. It is related to.

[Conventional technology]

Conventionally, in multicolor printing presses, a printing unit is provided for each color, and each printing unit 7) is provided with a plate cylinder. In these printing units, each plate cylinder is rotated in conjunction with a motor on the driving side, and a printing plate for each color is mounted on the circumferential surface of the cylinder.

On the other hand, in this type of multicolor printing press, the rotational phase of each plate cylinder often differs between printing units. In this case, the exchange from the old version to the new version is performed as follows.

First, as the i-th method, a method is adopted in which discharging the old plate (discharging plate) and supplying the new plate (plate feeding) are performed independently for each printing unit. That is, for each printing unit, align the plate cylinder with its plate ejecting position, open the gripper side plate vise and the tail side plate vise, and eject the old plate while reversing the plate cylinder.
After the plate is ejected, the plate cylinder is aligned with the plate feeding position, the edge of the new plate is held in the grip side vise, and the new plate is wrapped around the circumference while rotating the plate cylinder in the normal direction. The butt end of the new plate is held in a vise on the butt side, and the plate is evenly stretched and tightly attached to the circumferential surface of the body. FIG. 7 shows a plate change situation based on the above-described method in a four-color printing press.

Figures (a), (bl, fc), and (d) show the plate discharge and plate feeding status in the printing units for the fourth, third, second, and first colors, respectively, and the tl+ shown in the figure t
Z+ “At the timing of 2, from the 4th color to the 3rd color,
The printing plate is replaced from the third color to the second color, and from the second color to the first color printing unit.

Next, as a second method, a method is adopted in which the plate is discharged for each printing unit and then the plate is fed for each printing unit. That is, FIG. 8(al, (b)).

(C1, (d) 4th color, 3rd color, 2nd color 5 1st
As shown in the table below, plates are discharged sequentially from the 4th color to the 1st color printing unit, and then sequentially fed from the 1st color to the 4th color printing unit. Do a version.

[Problem to be solved by the invention]

However, according to such a printing plate exchange method, the seventh
As is clear from the exchange situation in Figures and Figure 8,
The total printing plate replacement time requires at least the sum of the plate discharge time and the plate feeding time for each printing unit, and further reduction is not possible.

[Means to solve the problem]

The present invention was proposed in order to solve such problems, and is a printing plate exchange method in which an old plate attached to the circumferential surface of the first to Nth plate cylinders that rotate in conjunction with each other is replaced with a new plate. , the first plate cylinder is aligned with the plate ejecting position, and the first plate cylinder
The old plate is ejected while the Nth plate cylinder is rotated in the reverse direction, and the old plate is ejected in the order of the plate cylinders that match the plate ejection position during the interlocked rotation of the first to Nth plate cylinders. At the same time, the final plate cylinder from which the old plate has been ejected is aligned with the plate feeding position, and the first to Nth plate cylinders are rotated in the normal rotation direction while feeding a new plate. , and thereafter, during the interlocking rotation of the first to Nth plate cylinders, the supply of new plates is proceeded in the order of the plate cylinders that match the plate feeding position.

[Effect]

Therefore, according to the present invention, when the second plate cylinder coincides with the plate discharge position while the old plate mounted on the first plate cylinder is being ejected, the old plate mounted on the second plate cylinder is removed. Ejection of the old version will begin.

Then, while the old plate attached to the second plate cylinder is being ejected, for example, if the third plate cylinder coincides with the ejecting position, the old plate attached to the third plate cylinder will be ejected. will be started.

In this way, when the old plate has been ejected from all the plate cylinders, the last plate cylinder from which the old plate has been ejected is matched with its plate feeding position. If this final plate cylinder is, for example, the Nth plate cylinder, when the N1th plate cylinder coincides with its plate feeding position while a new plate is being supplied to the Nth plate cylinder, this Supply of a new plate to the N-1th plate cylinder is started. Then, while the supply of a new plate to the N-1st plate cylinder is in progress, for example, if the N-2nd plate cylinder matches its plate feeding position, the new plate to the N-2nd plate cylinder is supplied. supply will begin.

Thereafter, new plates are supplied to all plate cylinders in the same manner.

〔Example〕

Hereinafter, the printing plate exchange method according to the present invention will be explained in detail.

FIG. 2 is a schematic side view of an embodiment of a multicolor printing press to which this printing plate exchange method is applied.

On the right side of the figure, 11 is the first color printing unit, 1-2
is the printing unit for the second color, 1-3 is the printing unit for the third color, l-4 is the printing unit for the fourth color, and the printing units t-i to 1-4 are the printing units for the plate cylinders 1-11 to 1-. It is equipped with 41. These plate cylinders 1-11 to 1-41 are interlocked and rotated by a drive motor 2 with a brake, and an absolute type low-return encoder 3 is provided at a predetermined position in the power transmission system. It is supposed to detect the rotation angle of the In addition, printing units l-1~
Automatic printing plate changing devices 4-1 to 4-4 are attached to 1-4, and when changing printing plates, the loaders 4-11 to 4-41 are tilted as shown by the dotted chain line in the figure, and the tip thereof is attached to the plate. Torso 1-II
~141 facing the trunk circumferential surface. The automatic plate changing devices 4-1 to 4-4 are equipped with a discharged plate gripping device and a plate feeding device, and the specific configuration thereof is described in Japanese Patent Application No. 1-337338, which was previously proposed by the present applicant. Since it has already been explained in detail, its explanation will be omitted here.

FIG. 3 is a block diagram of the control device that totally controls the automatic plate changing operation in this multicolor printing press. RAM 7 and interfaces 8 to 10 are arranged around the bus line BUS.
These are connected by The interface 8 relays between the input device 11 and the bus BUS, and the interface 9 relays between the machine control circuit 12 and the bus BUS. Further, the interface 10 is a mother [BUS
The command from the drive motor 2 is sent via the motor driver 13.
It also serves to send the rotation angle of the machine detected by the rotary encoder 3 to the bus line BUS.

FIGS. 4(a) and 4(b) are flowcharts showing control operations performed by the CPU 5. Hereinafter, with reference to this flowchart, a method for replacing printing plates in this multicolor printing press will be explained.

First, the CPU 5 reads the printing unit to be used that is given in advance via the input device 11 (step 101).
. That is, it reads which of the printing units 1-1 to 1-4 should have its printing plate replaced. In this embodiment, it is assumed that printing plates are replaced for all printing units Ll to 1-4. Then, by reading the machine control signal (step 102), it is determined whether the machine is stopped and in a state where the printing plate can be replaced.Step 103): The machine is in a state where the printing plate can be replaced. That is, if it is determined that the printing plate exchange can be started, the process proceeds to step 104. In step 104, it is checked whether a start switch (not shown) has been turned on.
If the start switch is turned on, the process advances to step 105 to start automatic plate exchange.

In step 105, a safety cover open signal is output to the machine control circuit 12, and the safety covers 1-12 to 1-42 attached to the printing units) if to 1-4 are opened. and,
The current rotation angle of the machine detected by the rotary encoder 3 is read as the current position (step 106), and the plate discharge position of the final printing unit, that is, the printing unit [4] is read (step 107). Then, the shortest rotation direction for making the current position the plate discharge position of the printing unit 1-4 is determined (step 108), and if the determination result is "forward rotation", a motor forward rotation signal is given to the motor driver 13 (step 109). ), if the judgment result is not "normal rotation", a motor reverse rotation signal is given to the motor driver 13 (step 110
). The signal supplied to the motor driver 13 causes the drive motor 2 to rotate forward or reverse, causing the plate cylinders 1-11 to
1-41 are interlocked to rotate forward or reverse. As a result, the rotation angle of the machine detected by the rotary encoder 3 changes moment by moment, and while reading this rotation angle of the machine as the current position (step 111), the current position becomes the plate discharge position of the printing unit 1-4. To check whether the current position has been reached, step 112), to stop outputting the motor rotation signal when the current position matches the plate discharge position, step 113), to stop the rotation of the drive motor 2. As a result, the plate cylinder 1-11
The interlocking rotations of the cylinders 1-41 to 1-41 are stopped, and the plate cylinder 1-41 is stopped at the rotation angle position (2), which is the plate discharge position, as shown in FIG. 5(a). At this time, printing units 1-1 to 1-
Assuming that the rotational phase of each plate cylinder 1-11 to 1-41 is different between 4, for example, the plate cylinder 1-31 has a width θ as shown in the figure.

The plate cylinder 1-21 stops at the rotational angular position ■ which is shifted by 02 as shown in fcl in the same figure.
The plate cylinder 1-11 stops at θ as shown in the same figure (C1).
It stops at the rotation angle position ■ which is shifted by 3.

Hereinafter, the rotational phases of the plate cylinders 1-41 to 1-11 are shown in Fig. 5 (
As shown in al to ldl, the explanation will proceed as they are different.

In such a situation, the CPU 5
Output a master ejection signal that prompts master ejection in Step 4 (Step E14)
). In response to this plate ejection signal, the machine control circuit 12 sends a loader arrival signal to the automatic printing plate exchange bag W4-4, and also sends a grip side plate vise open signal to the plate cylinder 1-41 and a bottom side plate vise open signal to the plate cylinder 1-41. Generates side vise open signal. Upon receiving the loader arrival signal, the automatic plate changing device 4-4 tilts the loader 4-41 as shown by the dashed line in FIG.
facing the circumferential surface of the torso. On the other hand, when the gripper side plate vise open signal and the bottom side plate vise open signal are generated, the plate ejecting operation in the printing unit L4 is started (point t8 shown in Fig. 1 (al)).
. That is, the gripper side plate vise 1-42 and the tail side plate vise 1-43 attached to the plate cylinder 1-41 are opened, and the plate cylinder 1-41 is opened.
The grip side end and the butt side end of the old version 14-4 attached to the peripheral surface of 41 become free. On the other hand, CPU5 is
Read the plate discharge positions of the remaining printing units used (step 115), and select the most recent plate discharge position in the reverse direction (
Step 116). That is, the plate cylinders 1-11 to 1-41 move in the direction of arrow A (reverse direction) shown in FIGS. 5(a) to (dl).
When rotated in conjunction with each other, the plate discharge position of the printing unit whose rotation angle position occupies the plate discharge position earliest, in this embodiment, the plate discharge position of printing unit 1-3 is selected. Then, by outputting a motor reversal signal (Step 1F), the drive motor 2 is rotated in the reverse direction, thereby interlockingly rotating the plate cylinders 111 to 1-41 in the reverse direction. With this interlocking rotation, the old plate 14-4 located on the circumferential surface of the plate cylinder 1-41 is drawn into the loader 4-41 of the automatic plate changing device 4-4 from its rear end, and is ejected. progresses. Also, plate cylinder 1-11
Through the interlocking rotation of ~1-41, the rotary encoder 3
The rotation angle of this printing machine detected by the printer changes every moment, and while reading this rotation angle of the printing press as the current position (step 11),
8) Check whether the current position has reached the plate discharge position of printing unit 1-3 selected in step 116.Step 9) When the current position matches the plate discharge position, the motor reverse signal is activated. Step 120)
, the rotation of the driving motor 2 is stopped. As a result, the interlocking rotation of the plate cylinders 1-11 to 1-41 is stopped, and the plate cylinders 1-31
stops at a rotation angle position that is reversed by 01 from the position shown in FIG. 5 (bl), and occupies that plate discharge position. Outputs a plate ejection signal that prompts plate ejection (step, block 1)
21). Upon receiving this plate ejection signal, the machine control circuit 12:
A loader arrival signal is sent to the automatic plate changing device 4-3, and a gripper side plate vise open signal and a tail side plate vise open signal are sent to the plate cylinder 1-31. Upon receiving the loader arrival signal, the automatic plate changing device 4-3 tilts the loader 431 as shown by the dashed line in FIG. 2, and makes its tip face the circumferential surface of the plate cylinder 1-31.

On the other hand, when the gripper side plate vise open signal and the bottom side plate vise open signal are generated, the plate discharging operation in the printing unit 1-3 is started (12 points shown in FIG. 1(b)). That is, plate cylinder 1-3
The grip side vise 1-32 and bottom side vise 1-33 attached to plate 1 are opened, and the grip side end and bottom side of old plate 14-3 attached to the circumferential surface of plate 1i 1-31 are opened. The ends will be free. Then, after confirming whether or not the plate discharge of all used printing units has been completed (step 122),
Returning to step 115, read each plate discharge position of the remaining printing units in use, select the latest plate discharge position in the reverse direction, that is, the plate discharge position of printing unit 12, and print cylinders 1-11 to 12.
1-41 are interlocked and rotated in the reverse direction. With this interlocking rotation, the old plate 14-3 located on the circumferential surface of the plate cylinder 1-31 is moved from its rear end to the loader 4 of the automatic plate changing device 4-3.
-31 and its ejection operation proceeds. Then, the plate cylinder 1-21 is moved θ from the position shown in FIG. 5 (C1).
When reaching the position reversed by 2, this rotation angle position is set as the plate discharge position and plate cylinder 1-11~! -41 stops, the loader 4-21 is tilted as shown by the dashed line in FIG. 2, and the plate discharge operation in the printing unit 1-2 is started (11 points shown in FIG. , plate cylinder 1-2
The grip side plate vise 1-22 and bottom side plate vise 1-23 attached to plate cylinder 1-21 are opened, and the grip side end and bottom side of the old plate 14-2 attached to the peripheral surface of plate cylinder 1-21 are opened. The end becomes free, and with the subsequent interlocking rotation of the plate cylinders 1-11 to 1-41, the old plate 14-2 is transferred from its rear end to the loader 4- of the automatic plate changing device 4-2. 21, and its discharge proceeds. Then, the plate cylinder 1-11 is shown in Figure 5 (
When a position reversed by θ from the position shown at d+ is reached, the plate cylinder t-it is set at this rotation angle position as its plate ejecting position.
~1-41's interlocking rotation stops, and loader 4-11 moves to the second position.
The plate is tilted as shown by the dashed line in the figure, and the plate discharging operation in the printing unit 1-4 is started (14 points shown in Fig. 1(d)). 1-12 and the bottom plate vise 1-13 are opened, and the plate cylinder 1-
The grip side end and the butt side end of the old plate 14-1 attached to the circumferential surface of the plate cylinder 11 become free, and the plate cylinder 1 that follows
-11 to 1-41, the old plate 14-1 is moved from its rear end to the loader 4- of the automatic plate changing device 4-1.
11, and its discharge operation proceeds.

When it is confirmed in step 122 that all printing units in use have completed discharging the plate, the plate feeding position of the last printing unit that has completed discharging the old plate, that is, the printing unit 11, is read (step 123). Then, a motor reversal signal is output (step 124), the plate cylinders 1-11 to 1-41 are rotated in the reverse direction, and while reading the current position of the machine (step 125), the current position is determined by the printing unit. Step 126) to check whether the plate feeding position of 1-1 has been reached; step 127) to stop outputting the motor reverse signal when the current position matches the plate feeding position; step 127) to stop the rotation of the drive motor 2. let As a result, the interlocking rotation of the plate cylinders 1-11 to 1-41 is stopped, and the plate cylinder 1-11 stops at the rotation angle position ■' which occupies the plate feeding position, as shown in FIG. 66(d). do. During this period, the old plate 14-i has been completely ejected since it passes through the 12 points shown in FIG. 1(d) during the reverse rotation. At this time, the plate cylinder 1-21 stops at the rotation angle position ■゛ shifted by 04 as shown in Figure (C), and the plate cylinder 1-31 is stopped by θ as shown in Figure (B). Misaligned rotation angle position ■
The plate cylinder 1-41 stops at a rotation angle position {circle around (2)}, which is shifted by .theta.6, as shown in FIG. In this situation, the CPU 5 outputs a plate feeding signal that prompts the printing unit 11 to feed the plate (step 128).

In response to this plate feeding signal, the machine control circuit 12 sends a plate insertion signal to the automatic plate changing device 4-1, and also sends a grip side plate vise close signal to the plate cylinder 1-11. send. The automatic plate changing device 4-1, which has received the plate insertion signal, begins its plate feeding operation and lowers the new plate (not shown), which has been sucked and held in advance, in FIG. 1 (point 18 shown at d+). , the gripper side end thereof is inserted into the gripper side plate vise 1-12 which is in the open state. On the other hand, when the gripper side plate vise close signal is generated, the new plate (with the gripper side end inserted), the gripper side plate vise 1
-12 is closed. Then, the CPU 5 stores the number of the printing unit 11 as the plate feeding completed unit (step 129), reads the plate feeding position and the bottom plate vise closing position of the remaining printing units in use (step 130),
The most recent plate feeding position or the bottom plate vise closing position in the normal rotation direction is selected as the stop position (step 131). That is, in the direction of arrow B (forward rotation direction) shown in Fig. 6 fa) to (d)
When the plate cylinders 1-11 to 1-41 are rotated in conjunction with each other, the earliest rotation angle position is the plate feeding position or the bottom plate vise closing position of the printing unit. Select a location. Then, it is checked whether the selected stop position is the plate feeding position or not (step 132). If the selected stop position is the plate feeding position, the process proceeds to step 133, and if not the plate feeding position, the process proceeds to step 140.

In the phase situation shown in FIG. 6, printing unit 1-2 occupies its plate feeding position earliest, so the process proceeds to step 133.

In step 133, a motor normal rotation signal is output, and the plate cylinder 1
-11 to 1-41 are interlocked and rotated in the normal rotation direction.

With this interlocking rotation, the new plate begins to be wrapped around the circumferential surface of the plate cylinder 1-11, and the supply of the new plate progresses. Further, due to the interlocking rotation of the plate cylinders 1-11 to 1-41, the rotation angle of the machine detected by the rotary encoder 3 changes every moment, and while reading this rotation angle of the machine as the current position (step 134), Its current position is printing unit 1-
I+! Check whether the plate feeding position of 2 has been reached or not! Acknowledge Step 1
35), when the current position matches the plate feeding position, the output of the motor normal rotation signal is stopped.Step 136), the rotation of the drive motor 2 is stopped. As a result, the plate cylinders 1-11 to 1
The interlocking rotation of -41 has stopped, and the plate cylinder 1-21 is
) It stops at a rotational angle position which is forwardly rotated by θ4 from the position shown in ), and occupies that plate feeding position.

In this situation, the CPU 5
- Outputs a plate feeding signal to prompt plate feeding at step 13.
7) Upon receiving this plate feeding signal, the machine control circuit 12 sends a plate insertion signal to the automatic plate changing device 4-2, and also sets the plate vR1-21 in the side plate vise. Send close signal. Upon receiving the plate insertion signal, the automatic plate changing device 4-2 starts its plate feeding operation (point t7 shown in FIG. 1(C)).
, lower the new plate (not shown) that has been suctioned and held in advance,
Grip side vise 1-2 with its grip side end open
Insert it into 2. On the other hand, when the gripper side plate vise close signal is generated, the gripper side plate vise 1-22 is closed with the gripper side end of the new plate inserted. Then, the CPU 5 stores the number of the printing unit 1-2 as the plate feeding completed unit (step 13B), and checks whether plate feeding has been completed for all used printing units (step 139).
), return to step 130.

In step 131 to be executed next, printing unit 1-3
The plate feeding position is selected, and in step 133 after passing through step 132, the plate cylinders 1-11 to 1-41 are interlocked and rotated in the normal rotation direction, and the feeding of a new plate from the plate cylinder 1-21 proceeds accordingly. . When the plate cylinder 1-31 reaches a position rotated forward by θ from the position shown in FIG. The interlocking rotation is stopped, and the plate feeding operation at printing unit 1-3 is started (point t8 shown in FIG. 1). That is, the plate changing device 4-3 lowers a new plate (not shown) which has been sucked and held in advance, and with the grip side end of this new plate inserted, the grip side plate vise 1-32 is closed. It will be done. Then, the number of printing unit i3 is stored as the plate completion unit, and the process returns to step 130 again. In step 131 to be executed next, the plate feeding position of the printing unit 14 is selected, and in step 133 after passing through step 132, the plate cylinder 1 -
11 to 1-41 are interlocked and rotated in the normal rotation direction, and the supply of a new plate to the plate cylinder 1-31 progresses accordingly. And plate cylinder 1
-41 reaches a position rotated forward by 06 from the position shown in FIG. Plate feeding operation in unit 1-4 is started (Fig. 1(a)
), that is, the plate changing device 4-4 lowers the new plate (not shown) that it has previously adsorbed and holds, and with the gripper side end of this new plate inserted, the gripper side plate is removed. Force 1-42 is closed. Then, the numbers of printing units 1-4 are stored as plate completion units, and the process returns to step 130 again.

In step 131 to be executed next, printing unit 1-1
The butt side vise closed position is selected. Therefore, the process advances to step 140 via step 132, and the number of the plate feeding completed unit is read. Then, in step 14, the read number of the plate feeding completed unit is compared with the number of the printing unit whose rear plate vise closed position has been selected.
1) If the selected printing unit is the plate feeding completed unit, the process proceeds to step 142. In this case, since the printing unit 1-1 is the plate feeding completed unit, the process proceeds to step 142.
In step 142, a motor normal rotation signal is output, and the plate cylinders 1-11 to 1-4I are interlocked and rotated in the normal rotation direction. Then, while reading the current position of the machine (step 143), check whether the current position has reached the bottom vise closing position of the printing unit 11 (step 144).
When the current position coincides with the vise-closed position of the butt side plate, the output of the motor normal rotation signal is stopped (Step 7 145), and the rotation of the drive motor 2 is stopped. As a result, plate cylinders 1-11~
The interlocking rotation of the plate cylinder 1-41 is stopped, and the plate cylinder 1-11 stops at a predetermined rotational angle position and occupies the rear plate vise closed position. In this situation, the CPU 5 generates a tail plate vise close signal to the printing unit il (step 146). When the butt side vise close signal is generated,
With the butt end of the new version inserted, use the butt side vise 1-13.
is closed and the automatic printing plate exchange bag? The loader 4-11 of 114-1 is retreated, and plate feeding to the printing unit 11 is thereby completed (see FIG.
tl shown in dl. Step 1), and then check whether plate feeding has been completed for all printing units used (step 1).
39), in step 131 after passing through step 130, select the bottom vise closed position of the printing unit 1-2, and execute steps 140 to 146, so that the printing unit 1
-2 completes plate feeding (t11 point shown in Figure 1 fc)). Thereafter, in the same manner, plate feeding to printing unit 1-3 is completed at point t1□ shown in Fig. 1 Cbl, and plate feeding to printing unit ■-4 is completed at point t13 shown in Fig. 1 (a). Complete. Then, in step 139, when it is confirmed that plate feeding has been completed in all used printing units, t as shown in FIG.
When the 13th point is reached, the process proceeds to step 147, where a safety cover open signal is output, and the safety covers 112 to 1-42 are closed in the printing units l-1 to 1-4.

In addition, in the above, in order to simplify the explanation,
It was assumed that the bottom plate vise close position in each printing unit does not come before the plate feeding position of any printing unit, but the bottom plate vise close position does not come before the plate feeding start position of any other printing unit. In this case, there is a possibility that the printing unit whose rear plate vise closed position was selected in step 131 is not the plate feeding complete unit, and in this case, the process advances to step 148 via step 141, The plate feeding position and bottom plate vise closing position of the remaining printing units used except for the plate vise closing position are stored in a submemory, and the plate feeding position and bottom plate vise closing position stored in this submemory are stored. Read out (step 149) and return to step 131.

Further, in the above-mentioned embodiments, the explanation has been made on the assumption that the printing plate is automatically replaced, but the method of the present invention can be similarly applied to the case where the printing plate is replaced manually.

Further, in the above-described embodiment, a four-color printing press has been described, but the same can be applied to a printing press equipped with two or more printing units.

〔Effect of the invention〕

As explained above, according to the printing plate exchange method according to the present invention, the first plate cylinder is aligned with its plate discharge position, and the first to
The old plate is ejected while the Nth plate cylinder is rotated in the reverse direction, and thereafter, the old plate is ejected in the order of the plate cylinders that match the plate ejection position during the interlocked rotation of the first to Nth plate cylinders. At the same time, the final plate cylinder from which the old plate has been ejected is aligned with the plate feeding position, and the first to Nth plate cylinders are rotated in the normal rotation direction while supplying the new plate, Hereinafter, during the interlocking rotation of the first to Nth plate cylinders, new plates are supplied in the order of the plate cylinders that match the plate feeding position, so the plate feeding time and plate discharging time are added for each printing unit. This makes it possible to reduce the total time needed to change printing plates.

Furthermore, this shortening of the printing plate exchange time has the ripple effect of reducing the number of rotations of the plate cylinder.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the printing plate exchange situation performed according to the flowchart shown in FIG. 4, and FIG. 2 is a schematic diagram showing an embodiment of a multicolor printing machine to which the printing plate changing method according to the present invention is applied. FIG. 3 is a block diagram of a control device that totally controls the automatic plate changing operation in this multicolor printing press, and FIG. A flowchart showing the operation,
Figure 5 is a diagram that also shows the phase situation of the plate cylinders in other printing units when the printing unit for the fourth color occupies its plate discharge position and stops, and Figure 6 shows the printing unit for the first color. FIGS. 7 and 8 are diagrams showing the phase situation of plate cylinders in other printing units when the plate feeding position is occupied, and FIGS. 7 and 8 are diagrams showing a conventional plate exchange situation. 1-1 to 1-4...printing unit, 1-11 to 1-4
1... Plate cylinder, 2... Drive motor, 3... Row reencoder, 4-1 to 4-4... Automatic printing plate change device, 5... CPU, 14-1-14- 4... Old version.

Claims (1)

[Claims] In a printing plate exchange method in which an old plate attached to the circumferential surface of first to Nth plate cylinders that rotate in conjunction with each other is replaced with a new plate,
After aligning the first plate cylinder with its plate ejecting position, the first to Nth plate cylinders are rotated in the reverse direction while ejecting the old plate. During the interlocking rotation, the old plates are ejected in the order of the plate cylinders that match the plate discharge position, and the last plate cylinder that has completed discharging the old plate is aligned with its plate feeding position, and then the first to third plate cylinders are The new plate is supplied while rotating the N plate cylinder in the normal rotation direction,
A printing plate exchange method characterized in that, during the interlocking rotation of the first to Nth plate cylinders, the supply of new plates proceeds in the order of the plate cylinders that match the plate feeding position.