JPH0310045Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a fixing structure for a direct printing plate material in an offset printing machine.

<Prior art> Conventionally, in an offset printing machine, a plate material 1 is fixed to the outer periphery of a plate cylinder (master cylinder) 2, and character figures on a planar surface of the plate material 1 are placed on a rubber cylinder (blanket) 3 on a rubber cloth surface. The image is transferred and printed on the surface of paper 5 which is held between blanket cylinder 3 and impression cylinder 4 under pressure.

Generally, it is standard to use a metal aluminum thin plate that does not expand or contract as the plate material 1, but even if the quality of the printing finish is excellent, the aluminum plate itself and the film photography and aluminum plate that are carried out in the pre-process. Recently, as a simple method, paper or a synthetic resin film such as polyester has been used as a plate material, since development is required and costs are high.

These plate materials 1 are fixed by hooking one end of the plate material 1 to one part of the plate cylinder 2, pulling the other end, and pressing and fixing the plate material 1 along the outer peripheral surface of the plate cylinder 2 with a leaf spring or the like. Printing work is performed by rotating the plate cylinder 2, blanket cylinder 3, and impression cylinder 4.

<Problems to be solved by the invention> When the above-mentioned plate material 1 is paper or synthetic resin film, the paper or film with weak tensile strength gradually stretches during printing, and There was a problem with the dimensional accuracy, and especially when printing in multiple colors, color misalignment occurred.

<Means for Solving the Problems> The present invention is intended to improve the above-mentioned drawbacks of the conventional technology, and consists of the following configuration.

That is, a low-ductility flexible film (for example, a synthetic resin film) is interposed between the plate cylinder and the plate material (direct plate making), and the plate cylinder and the intermediate film (hereinafter referred to as the base material) are made of a strong adhesive. The plate material and the base material are bonded together using a weak adhesive, and both adhesives have an adhesive strength that allows them to be peeled off.

<Example> The embodiments shown in the figures will be described below.

FIG. 1 relates to a base material, in which 9 is a flexible synthetic resin film, such as a polyester film, preferably one with as little ductility as possible.
Reference numeral 10 bonds the base material 9 to the plate cylinder 2 using an adhesive with high adhesive strength, such as BPS-4782D from Toyo Ink Manufacturing Co., Ltd. On the other hand, 8 is an adhesive with low adhesive strength, such as Toyo Ink Manufacturing Co., Ltd. BPW-
4960, plate material (direct plate making) 1 to base material 9
Glue. 11 and 11 are waxed separate papers that protect the adhesives 8 and 10 during storage;
Peel it off when using.

FIG. 2 is an enlarged partial sectional view of the plate cylinder 2, in which a base material 9 is adhered to the surface of the plate cylinder 2 via a strong adhesive 10, and a weak adhesive 8 is applied to the surface of the base material 9. A state in which a plate material 1 (direct plate making) 1 is bonded through the plate is shown.

FIG. 3 shows the main parts of an offset printing machine, in which an ink cylinder 6 and a water cylinder 7 are roll pressed into contact with a plate cylinder 2 to which a plate material 1 is attached, and a blanket cylinder 3, a rubber cylinder 3, An impression cylinder 4 is pressed against the lower side of the blanket cylinder 3, and the printing paper 5 passes between the blanket cylinder 3 and the impression cylinder 4 to perform a printing operation.

Here, when one printing is completed, the plate material 1, which is direct plate making, is peeled off from the base material 9. At this time, since the base material 9 is bonded to the plate cylinder 2 via the adhesive 10 with a high adhesive strength, the plate material 1 that was bonded to the base material 9 via the adhesive 8 with a low bonding strength is replaced with the base material. 9 can be easily peeled off from the base material 9 while being adhered to the plate cylinder 2.

At this stage, the plate material 1 to be printed next is adhered to the base material 9 via a weak adhesive 8, and the next printing is performed.

After repeating the number of printings in this way, when the adhesive strength of both adhesives 8 and 10 becomes weak after about 20 to 30 times, the base material 9 is peeled off from the plate cylinder 2 and a new base material 9 is applied. Lock it in place using the same operation as above and continue working.

Note that since adhesives 8 and 10 with different adhesive strengths are attached to the front and back sides of the base material 9, the coloring of the separate paper 11 attached to the outside of these is changed, for example, yellow on the plate cylinder side and yellow on the plate cylinder side. The wood side is blue etc.
Facilitate its identification.

<Effects of the invention> As described above, the present invention adheres the base material 9 made of flexible film to the outer surface of the plate cylinder 2 via the strong adhesive 10, and further attaches a weak adhesive to the surface of the base material 9. The base material 9 is attached in the middle, unlike the conventional method of directly attaching the plate material 1 to the plate cylinder 2 and mechanically fixing its ends. In addition, a strong adhesive 10 is applied to the plate cylinder side of the base material 9, and a weak adhesive 8 is applied to the plate side, so that only the edges of the plate material are clipped as in the conventional method. Compared to other plate materials where the contact surface of the plate cylinder is in a free state, the entire contact surface of the plate cylinder, base material, and plate material is completely bonded with adhesive, which makes printing easier. As printing progresses, the plate material is stretched as little as possible, and unlike conventional printing plates, as the number of printings progresses, especially plate materials made of paper or semi-rigid synthetic resin film material are stretched as much as possible. This eliminates the problem of color misalignment in multi-color printing, and makes it possible to print with good dimensional accuracy.

In order to replace the used plate material, since we use an adhesive with low adhesive strength, it can be easily peeled off from the base material and can be replaced with a new plate material for repeated use. At the stage where the surface strength adhesive or the above-mentioned weak adhesive has weakened the adhesive force, the base material itself is peeled off from the plate cylinder.
The effect is that you can then replace it with a new base material and continue the work in the same way.

In addition, in the above explanation, an example was described in which the adhesive is applied to the entire contact surface of the plate cylinder, base material, and plate material, but the size of the printing area of the plate material and the adhesive strength of the adhesive used Of course, partial surface bonding may be used depending on the circumstances.

Furthermore, the technical idea of the present invention can also be applied to letterpress printing.

[Brief explanation of the drawing]

The figures show an embodiment of this invention. Figure 1 is an enlarged cross-sectional view showing the structure of the base material, Figure 2 is an enlarged partial cross-sectional view showing the plate material fixed to the plate cylinder, and Figure 3 is an offset view. FIG. 2 is a perspective view of the main surface of the printing press. 1... Plate material, 2... Plate cylinder, 8... Weak adhesive, 9... Base material 9, 10... Strong adhesive.

Claims (1)

[Scope of utility model registration request] Peelable and strong adhesive 10 on the outer surface of the plate cylinder 2
A base material 9 made of a flexible film with low ductility is adhered through the base material 9, and a plate material 1 is adhered to the outer surface of the base material 9 through a peelable and weak adhesive 8. Features: Plate fixing structure for offset printing machines.