JPS60120059A - Apparatus for fixing plate on plate cylinder - Google Patents

Abstract

PURPOSE:To enable a quick adjustment of plate with the mounting thereof on a plate cylinder without a slack by injecting a pressure fluid into fiexible tube interposed between the end wall of a concave section in a plate cylinder and a lower tooth of a gripper to make the gripper slide displaceable. CONSTITUTION:A gripper 3 provided in a concave section 2 in a plate cylinder 13 has upper teeth 3a and lower teeth 3b for gripping the end of a plate inserted therebetween and the lower teeth 3b slides freely along the bottom of the concave section 2. A flexible tube 17 is interposed between the circumferential end wall 2a of the concave section 2 and the lower teeth 3b. A stopper 19 is projected on the side opposite to the flexible tube 17 in the circumference direction of the plate cylinder 13 sandwitching the lower teeth 3b and a spring 20 is interposed between the stopper 19 and the lower teeth 3b and works to put the lower teeth 3b to the original position. An introduction port 18 allowed to feed a fluid pressure is provided on the tube 17 and a fluid is injected into the tube 17 to expand it so that the lower teeth 3b are slidingly displaced against the force of a spring 20 together with the upper teeth 3a. When the displacement reaches a specified level, the injection is stopped to fix the plate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plate fixing device to a plate cylinder in an offset sheet-fed printing press.

Generally, as shown in FIG. 5, the plate cylinder of an offset sheet-fed printing press has a recess 2 in a part of its outer peripheral surface, and a gripping device 3 for tightly gripping the edge of the printing plate is installed inside the recess 2. It is being The gripping device 3 consists of upper teeth 3a and lower teeth 3b, and the lower teeth 3b are supported at the bottom of the recess 2 so as to be slidable in the circumferential direction of the plate cylinder. One of the pair of gripping devices 3 is for gripping the leading end (bite) of the printing plate, and the other is for gripping the rear end (biting end) of the printing plate. A plate tensioning bolt 4 is screwed into the lower tooth 3b in the circumferential direction of the plate cylinder, and its tip abuts against the end wall of the recess 2.

Before attaching the printing plate to the printing cylinder, both the gripping devices for the front end, ie, the gripping device, and the rear end, ie, the gripping surface, of the printing plate are returned to their original positions.

When attaching a printing plate, first insert the leading edge of the printing plate into the gripping device 3, move the upper teeth 3& against the lower teeth 3b to clamp it, and then rotate the plate cylinder to hold the rear end of the printing plate. Insert it into the gripping device 3 on the buttock side and clamp it.

However, clamping at the end of the grip creates slack between the printing plate and the plate cylinder, so in order to eliminate this slack, first the plate gripping device 3 at the end of the grip is moved into the recess by rotating the plate tensioning melt 4. Pull the printing plate by sliding it in the direction away from the end wall of No. 2.

However, since it is not possible to eliminate the slack in the gripping portion of the printing plate, the gripping device 3 on the gripping side is also slid in the same manner to pull the printing plate in the circumferential direction of the plate cylinder. The plate tension bolts 4 are provided at several locations in the axial direction of the plate cylinder, and in order to pull the printing plate uniformly in the width direction, it is necessary to tighten all the plate tension bolts 4 by a certain amount.

However, in the case of large size printing machines such as A double size,
There are four or five stencil bolts 4, and it is a troublesome task to tighten and adjust them evenly with a spanner.

The process of pulling the printing plate using the plate gripping device on the gripping side is called retightening, and if the retightening is not done consistently, the printing plate is installed bent in the circumferential direction of the plate cylinder, resulting in a so-called twist registration error. It turns out.

This twisting registration error is corrected by temporarily stopping printing and adjusting the plate tensioning bolt of the printing plate gripping device. During this time, printing is hindered, resulting in a large loss in productivity.

The present invention has been made in order to solve the above-mentioned drawbacks of the prior art.The purpose of the present invention is to enable the printing plate to be mounted on a printing plate cylinder with high precision and without slack, and to be able to be adjusted in a short time. An object of the present invention is to provide a printing plate fixing device that can be easily used.

In the present invention, a lower flexible tube is interposed between the circumferential end wall of the concave portion of the plate cylinder and the lower tooth, and the lower tooth is inserted from the opposite side of the tube by sandwiching the lower tooth in the circumferential direction of the plate cylinder. A spring is provided that acts in the direction of returning to the original position, and the pipe is provided with a fluid pressure inlet that can supply fluid pressure, and the supply of fluid pressure into the pipe causes the pipe to expand, causing the lower teeth and the upper teeth to receive the force of the spring. It should be possible to resist and displace it.

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows an offset sheet-fed printing press.
0 is a paper feed section, and the printing paper is transferred from the paper feed section 10 to the printing unit l'
The sheets are fed one by one through ka, 11b, 11c, and 11d, and are ejected by the paper ejecting section 12. Each printing unit includes a plate cylinder 13, a blanket cylinder 14, and an impression cylinder 15.
, an inking device, a dampening water device, etc. (not shown).

As shown in FIG. 2, the plate cylinder 13 has a recess 2 in which a plate gripping device 3.3 is provided.

In the illustrated example, the gripping device 3 on the right side has a stenciling bolt 4 like the conventional gripping device, and the gripping device on the left side has the configuration according to the present invention, but the gripping device on the right side also has the configuration according to the present invention. may be provided.

The gripping device 3 according to the invention has upper teeth 3a and lower teeth 3b, between which the edge of the printing plate is gripped. lower teeth 3b
An eccentric shaft 5 is rotatably supported on the top, and upper teeth 3 are mounted on the eccentric shaft 5.
a is rotatably attached. The eccentric shaft 5 is the upper tooth 3a
If you insert a rod etc. into the hole in the center of the eccentric shaft 5 and rotate the eccentric shaft, the upper tooth 3a and the lower tooth 3b will be separated.
A gap can be provided between the distal end gripping parts. That is, the upper tooth 3a becomes rotatable, and a gap is created between the upper tooth tip gripping portion and the lower tooth tip gripping portion. If the end of the printing plate is inserted into this gap and the eccentric shaft is reversed, the end of the printing plate will be firmly sandwiched between the tip gripping portions of the upper and lower teeth. In addition,
The above-mentioned upper and lower tooth opening/closing mechanisms are well known.

The lower tooth 3b is slidable in the circumferential direction along the bottom of the recess 2, and a material such as polyurethane, vinyl chloride resin, etc. is provided between the end wall 2a of the recess 2 in the circumferential direction and the lower tooth 3b. A tube 17 made of flexible material is inserted. As shown in FIG. 3, the lower tooth 3b has a length that covers almost the entire length of the plate cylinder 13, and the upper tooth 3a is divided into several pieces in the longitudinal direction of the plate cylinder 13, for example. The tube 16 is then preferably provided over the entire length of the lower teeth 3b. The tube 16 has, for example, a fluid pressure inlet 18 at one end thereof.

A stopper 19 is protruded from the opposite side of the tube 17 across the lower teeth 3b in the circumferential direction of the plate cylinder, and a spring is interposed between the stopper 19 and the lower teeth 3b. This spring force presses the lower tooth 3b so as to return it to the left in FIG. 2 to the original position. As shown in FIG.
A large number of springs are newly provided in the longitudinal direction of the plate cylinder, and the same number of springs are also provided.

To wrap the printing plate around the printing cylinder, first wrap the upper teeth 3a on the biting side.
This is done by inserting and clamping the end of the printing plate between the lower teeth 3b, rotating the plate cylinder with the cylinder inserted, and clamping the end of the plate in the same way as the gripping side. The bite at this time,
The printing plate gripping device 3 at the end of the bite is at the original position.

In this way, clamping only the grip and the end of the bite will cause slack between the printing plate and the plate cylinder, so in order to eliminate this slack and bring the printing plate into close contact with the plate cylinder, clamping of both the grip and the bottom of the grip is necessary. The plate gripping device 3 is slid in the circumferential direction. At this time, the plate gripping device must be pulled uniformly in the axial direction of the plate cylinder.

Therefore, in the plate fixing device of the present invention, after the plate is clamped, fluid is supplied from the fluid pressure inlet 18 into the pipe 17 between the lower teeth 3b on the gripping side and the end wall 2a of the recess 2. For example, injecting air. As a result, the tube 17 expands, and the clamping side plate gripping device 3 slides toward the stopper 19 while compressing the spring force due to the fluid pressure. Then, air injection is stopped when a predetermined sliding displacement is achieved. In addition, tube 1
7 may be divided into several parts and provided instead of providing a single -C that spans almost the entire length of the plate cylinder as shown. tube 1
Polyurethane resin, vinyl chloride resin, etc. as the material of No. 7 are preferable in terms of expansion, contraction properties and strength, but other elastic materials can also be used.

Injection of fluid through the fluid pressure inlet 18 can be performed by inserting a fluid pressure supply nozzle into the four ports, and it is also possible to use a known one-touch coupling for the injection part. In this case, the side of the fluid pressure introduction port 18 becomes a socket, and the side of the supply nozzle becomes a plug. If a two-way opening/closing type coupling with an automatic pulp mechanism is used for both the socket and the plug, both the socket and the plug will be in a completely sealed state the moment they are disconnected, and no fluid will leak.

When the printing plate is fixed in the manner described above, the state shown in FIG. 3 is obtained. The printing plate is designated by the numeral 21.

When printing is finished and you want to remove the printing plate from the plate cylinder, use tube 17.
Remove the fluid sealed in the. As a result, the printing plate gripping device returns to its original position by the force of the spring.

The fluid may be discharged from the fluid pressure inlet 18, or
A separate outlet may also be provided. Fluid pressure inlet 1
An example using 8 is explained with reference to FIG. 4, in which each printing unit lla, llb, llc or lid is connected to a single compressor 5 by means of electromagnetic discrimination. The solenoid valve also has a fluid discharge pipe, and when the solenoid valve is switched to one side, the compressed air from the compressor 5 is injected into the pipe 17 through the solenoid valve and the coupling O, and then to the other side of the solenoid valve. By switching , the air inside the pipe is discharged via the discharge f26.

In the embodiments described above, the structure of the present invention is applied only to the plate gripping device on the grip side, but it can also be applied to the bottom side of the grip.

In the case of the printing plate fixing device of the present invention, since it is impossible to correct the twisting register error, which was conventionally done by adjusting the plate-stretching resert, the twisting register error is corrected by a known twisting device.

As explained above, by using the present invention, printing plates can be mounted on the plate cylinder with high accuracy, registration errors due to mounting errors can be eliminated, and registration time can be significantly shortened, and plate tensioning can be improved. Compared to the conventional method of adjusting with a spanner, work efficiency can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an offset sheet-fed printing press, Fig. 2 is a sectional view of a plate cylinder equipped with the printing plate fixing device of the present invention, Fig. 3 is a plan view thereof, and Fig. 4 is a fluid supply and discharge. FIG. 5, which shows the pipe system, is a sectional view of a plate cylinder equipped with a conventional plate fixing device. 2... Recessed part, 2a... End wall of the recessed part, 3... Gripping device, 3a... Upper teeth, 3b... Lower teeth, 4... Printing bolt, 10... Paper feed part, 11a-lid...printing unit, 12...paper discharge section, 13...plate cylinder, 17.
...Pipe, 18...Fluid pressure inlet, 19...Stock pressure, addition...Spring, 21...Printing plate, U...Solenoid valve,
5...Compressor, or...discharge pipe. Applicant's agent Kiyomi Inomata 3rd, 4th, 5th

Claims (1)

[Claims] 1. A gripping device consisting of upper teeth and lower teeth for tightly gripping the edge of a printing plate inside a recess provided in a part of the outer peripheral surface of a plate cylinder of an offset sheet-fed printing press. In a device for fixing a printing plate to a printing cylinder, which is provided so as to be slidably displaceable in the circumferential direction of the printing cylinder, and a gripping device can be fixed at an arbitrary displacement position, a circumferential end wall of the recess of the printing cylinder and A flexible tube is interposed between the lower teeth, and a spring is provided that pinches the lower teeth in the circumferential direction of the plate cylinder and acts in the direction opposite to the tube to return the lower teeth to the original position. The pipe is provided with a fluid pressure inlet that can supply fluid pressure, and by supplying fluid pressure into the pipe, the pipe is expanded and the lower teeth can be displaced together with the upper teeth against the force of the spring. Plate fixing device. 2. The plate fixing device according to claim 1, wherein a stopper is provided protruding within the recessed portion, and a spring is interposed between the stopper and the lower teeth.