JPH10235834A - Plate bending method of printing plate and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a sure and precise plate bending of printing plates having a large number of sizes with a simple method by a method wherein the embossing of a printing plate is executed between a V-groove and a V-blade under the condition that a heating means is provided at the tip of a V and the center register mark of the printing plate is employed as positioning datum lines. SOLUTION: The device is equipped with a pedestal, on which a printing plate 5 is placed and at one end of which a stopper part is provided, a V-groove, which is provided at one end of the pedestal parallel to the stopper part and printing plate positioning datum lines or scales, which are produced by marking scale parts at time positions corresponding to the central parts in the longitudinal directions of various kinds of printing plates, and provided at least along one side, side, which is normal to the V-groove, of the pedestal. By pressing the printing plate 5 placed on the pedestal under the condition being mated to the center register mark and the stopper part, between a V-groove and a V-blade by coming down above the V-groove through a printing plate protecting sheet 4 in order to realize its plate bending. As the heating form, heaters 7 may be provided at least on either one of the V-groove and the V-blade or at some part of them. However, in order to improve its bending accuracy either one of the tips of the V-groove and of the blade 6 is heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for mounting a printing plate on an offset rotary printing press (hereinafter referred to as "off-press"), and more particularly to a method for mounting a printing plate on a plate cylinder using a grooved type plate curved shaft. The present invention relates to a method and an apparatus for stably fixing a printing plate, and is particularly useful for a form printing machine used for business form printing (hereinafter referred to as BF printing).

[0002]

2. Description of the Related Art As a typical printing plate used for the printing, a PS plate using an aluminum plate as a support is known. However, the PS plate is a direct printing method using a silver halide photographic method because of a complicated plate making process. By making the printing plate capable of plate making into various synthetic resin supports such as polyethylene terephthalate, it comes to have a desired physical strength, and in contrast to the conventional PS plate, these direct printing plates have a sheet-fed printing machine. Of course, it has the performance that can be sufficiently used for an offset press.

However, a gripping mechanism for bending and mounting a printing plate on a plate cylinder of an off-press printing press, which is currently widespread in the printing industry, has been designed based on the bending characteristics of a metal plate such as aluminum. The printing plate using a synthetic resin as a support as described above has a force to restore the original shape even if it is bent at a predetermined angle, and it is difficult to maintain the bending angle. However, there is a problem that the printing accuracy is deteriorated as a result.

[0004] As for the plate bending means of such a printing plate, for example, Japanese Utility Model Laid-Open No.
Japanese Patent Application Laid-Open No. 9-90444, Japanese Utility Model Application Laid-Open No. 2-40532, and Japanese Patent Application Laid-Open No. 62-152856, etc., bend both ends of a printing plate pressed and fixed on a pedestal with a bending block that can be swiveled to one side as a center of rotation. Method and JP-A-61-20
No. 6698, FIGS. 3 to 6, the printing plate on the opened slidable fold forming groove is bent by a flat pressing blade, and after the blade is pulled up, the printing plate is further folded into the fold forming groove. A method of closing and pressing has been proposed.

However, in any of these methods, a plurality of movable parts are required, and there is a difficulty in bending accuracy in an operation procedure. Sufficient problems have not yet been solved over the distortion of the printing plate and the occurrence of undesired scratches on the printing plate.

[0006]

SUMMARY OF THE INVENTION The present invention aims at effective bending of a plate over its accuracy and workability, and the solution is to use an efficient method for an off-wheel printing plate, especially a BF printing plate. On offer. As is well known, the BF printing press is a printing plate,
The plate butt is loaded into the plate cylinder groove, which is very tight in both width and depth. Therefore, the bending accuracy of the printing plate is required to be stricter than that of other printing methods.

Further, it is necessary to prepare various different sizes of the BF printing plate corresponding to the plate cylinder size corresponding to the longitudinal direction of the printed matter. Here, the basic concept of the present invention is to eliminate the disadvantages of the prior art by selecting a plate bending shape and specifying a heating method, and it is possible to reliably bend printing plates of many sizes by a simple method. It is to try.

[0008]

SUMMARY OF THE INVENTION An aspect of the present invention resides in embossing a printing plate between a V-shaped groove and a V-shaped blade. In a preferred embodiment, a heating means is provided at the V-shaped tip. This is a bending method that uses the center registration mark of the printing plate as a reference line for positioning to enable uniform bending accuracy at various printing plate sizes, and a protective sheet is placed between the printing plate and the plate bending jig. The point is to intervene.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The plate bending method according to the present invention comprises a pedestal on which a printing plate is placed and having a stop at one side, a V-shaped groove parallel to the stop at one end of the pedestal, and a direction perpendicular thereto. The printing plate positioning reference line on at least one side of the pedestal, that is,
Scales marked with scales are provided at positions corresponding to the respective center portions (center registration mark portions) in the longitudinal direction of the various printing plates. Pressing between the V-shaped blades via the printing plate protection sheet enables plate bending.

[0010] The V-shaped herein is intended to achieve a so-called desired angle at the time of loading the plate cylinder as close as possible, and the angle is 50 to 80 degrees, preferably 60 degrees. The depth and the opening length may be adjusted in accordance with the correlation with the plate cylinder holding groove of the applicable web offset printing press (BF printing press).

The protective sheet for the printing plate protects the printing plate from undesired damage and scratches, and at the same time, increases the frictional force of the printing plate between the groove and the blade during pressing and bending to suppress unnecessary slippage. Allows for favorable folding angles. The protective sheet may be provided only on at least the printing plate side of the printing plate, but since the plate bending of the printing plate itself is not limited to the folding direction to the same surface side, application on both the groove side and the blade side is a further modification of the present invention. To achieve certain objectives. The material of the protective sheet is made of various synthetic resins including polyethylene, polypropylene and polyethylene terephthalate.
There are no special requirements for the properties of commercially available adhesive tapes. Its thickness can be appropriately selected from those having a thickness of 50 to 200 μm.

The heating mode may be such that at least one of the V-shaped groove and the blade and at least a part thereof have a heat-generating part. It is preferable to heat at least one of the tip of the V-shaped groove and the tip of the blade, since such a problem that a wave is formed without obtaining the property is caused.
This is intended for selective local heating at the folding edge of the printing plate and avoids deteriorating undesirable plate surface characteristics due to heating of other printing plate portions. The heating temperature here can be appropriately selected depending on the material and thickness of the applied printing plate support. Generally, it is in the range of 50 ° C to 100 ° C, preferably 50 ° C to 80 ° C.

Further, releasing the heating means only and holding the blade pressed, without raising the blade after the bending by heating and pressing, promotes the object effect of the present invention. The time can be selected within a range of 1 to 2 minutes or less according to the above-mentioned characteristics of the printing plate.

Such local heating of the tip means a selective spot heating of the printing plate bending properties, in particular the BF printing itself, the effective printing section, the printing plate and the plate cylinder mounting of the printing press compared to other sheet-fed printing. The size ratio between the three grooves is small, that is, in the BF printing method, as is well known, the printing length as well as the printing width matches the plate cylinder width of the printing press and its length. Therefore,
If the printing plate is heated at the time of bending the plate bottom or plate head, it is necessary to avoid hindering the plate surface properties, and the tip heating here is significant in itself.

FIG. 1 shows a printing plate bending machine according to the present invention. FIG. 2 is a side view of a plate bending mechanism of the plate bending machine, and FIG. 3 is a side view showing a printing plate bending procedure. Can be arbitrarily changed according to the size of the applied printing plate and the workability of bending the printing plate.

[0016]

According to the present invention, the printing plate surface of the resin film plate can be bent with high accuracy, and such a printing plate can be easily loaded on the gripping head and the gripping edge of the printing press. Printing characteristics can be maintained by a combination of local heating and a plate surface protection sheet.

[Brief description of the drawings]

The drawings show a plate bending apparatus for carrying out the present invention and an embodiment thereof.

FIG. 1 is an overall view of an apparatus for performing plate bending according to the present invention.

FIGS. 2A and 2B are schematic partial cross-sectional views showing a blade, a heated portion, and a protective sheet of the plate bending apparatus.

[Brief description of reference numerals]

 Reference Signs List 1 V-shaped groove 2 Reference line 3 Pedestal 4 Protective tape 5 Printing plate 6 Blade 7 Heater

Claims (6)

[Claims] In a method of bending a printing plate using a resin film as a support, a bent portion of the printing plate is formed by forming a bent portion of a printing plate having a heating means at one end of a base on which the printing plate is placed; A method of bending a printing plate, comprising heating and pressing between a blade having the same shape that can be raised and lowered and provided in the plate. 2. A printing plate positioning reference line is provided on a base,
2. The plate bending method according to claim 1, wherein the printing plate is aligned with the reference line and pressed. 3. The plate bending method according to claim 1, wherein a protective sheet is interposed between the printing plate and the V-shaped groove. 4. The plate bending method according to claim 1, wherein the angle of the V-shaped groove is 60 to 70 degrees. 5. The plate bending method according to claim 1, wherein the tip of the V-shaped groove is heated. 6. A heating V-shaped groove is provided at one end of a printing plate mounting pedestal having a reference line for positioning a printing plate center after various types of plate making, and a rectangular shape for storing a vertically movable V-shaped blade directly above the groove. A plate bending apparatus comprising the support table, a pedal for lowering the blade below the support table, and a roll-shaped film orbiting the printing plate in the longitudinal direction on the V-shaped groove of the base.