JPH03380Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field This invention relates to a compressible offset blanket. More particularly, the present invention relates to a compressible offset blanket for printing, which includes a compressible layer between a surface layer and a reinforcing layer.

<Background and Prior Art> Conventionally, the above-mentioned compressible offset blanket has been designed to provide compression between the surface layer 1 and the reinforcing layer 2, as shown in FIG. The construction of gender 3 is being carried out.

This compressible layer 3 may be made of, for example, a cellular material made of non-woven fabric impregnated with latex (see Japanese Patent Publication No. 37-13110), or made of a rubber sponge manufactured using a foaming agent ( (see German Patent No. 1165046), etc. have been proposed.

However, the former case has not been put to practical use because it cannot exhibit the desired printing characteristics. In the latter case, it is actually difficult to form bubbles a of a uniform diameter within the compressible layer 3, which has an extremely thin thickness of about 0.2 to 1 mm, and it is difficult to generate uniform printing pressure over the entire surface of the bracket. However, further improvement is desired.

For this reason, a compressible layer 3 has been developed in which the compressible layer 3 is made of a rubber elastic material mixed with micro hollow spheres of soluble or crushable material such as thermoplastic plastic (see Japanese Patent Publication No. 7371/1983). There is a problem that the manufacturing process becomes complicated.

<Purpose> The purpose of this invention is to provide a compressible offset blanket that can solve the above-mentioned problems based on a principle completely different from that of the above-mentioned known technology.

<Structure> The structure of this invention to achieve the above object is that in a compressible offset blanket in which a compressible layer is constructed between a surface layer and at least one reinforcing layer, the compressible layer is It is characterized in that it is constructed of an elastic sheet bent into an uneven cross-sectional shape.

<Example> Next, Figures 1 to 3 show examples of this invention.
This will be explained below with reference to the figures.

A shows the entire compressible offset blanket, one of which is the surface layer. The surface layer 1 has a two-layer structure consisting of an oil-resistant rubber layer 10 and a fiber layer 11 laminated on the back surface thereof. 2 is a reinforcing layer, and in the case shown, an intermediate rubber layer 2 is provided between the rubberized fiber backing layers 20 and 20'.
1 is interposed.

Reference numeral 3 designates a compressible layer which is a feature of this invention and is constructed between the surface layer 1 and the reinforcing layer 2, and is comprised of an elastic sheet 30 bent into an uneven cross-sectional shape. This compressible layer 3 has an overall thickness t.
The formation pitch P of the convex portions 31 is approximately 0.1 to 1.0 mm.
Approximately 10 to 100μ is suitable. Also elastic sheet 3
0, a rubber sheet having a JIS hardness of about 50 to 70 is suitable. Furthermore, the cross-sectional shape of the recess is
In addition to the wavy shape shown in the figure, various shapes can be used, such as a chevron-shaped uneven shape as shown in FIG. 3, and a zigzag shape (not shown). Formation into such an uneven cross-sectional shape is performed by forming the elastic sheet 30
This can be easily carried out by press molding using a mold engraved with a desired uneven pattern (embossing) or by molded roll processing.

As a result of testing the blanket A with the above configuration installed in a printing machine, it was found that the outline of each of the countless dots (halftone dots) that make up each print line was very sharp, and the diameter of the halftone dots was smaller than the predetermined diameter. There is no so-called "thickening phenomenon" where halftone dots become thicker, and there is no so-called "skipping phenomenon" where spots appear in each dot. It was confirmed that extremely good printed images could be obtained, with no striped shading called "shock marks" occurring.

Note that the surface layer 1 may have a single layer structure consisting only of the oil-resistant rubber layer 10 without forming the fiber layer 11, and the elastic sheet 30 may also be made of other elastic material such as a urethane sheet instead of the rubber sheet. It can also be carried out using a sheet. Furthermore, reinforcement layer 2
However, it is sufficient that at least one layer is composed of the fiber backing layer 20.

<Effects> According to the compressible offset blanket of this invention constructed as described above, the compressible layer is composed of an elastic sheet bent into an uneven cross-sectional shape. It can exhibit elasticity, have sharp halftone dots, and produce very good printed images without thickening, voids, or shadows.

Furthermore, the compressible layer itself can be formed easily and at low cost, and a material that exhibits various excellent practical effects can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view, FIG. 2 is a perspective view of an elastic sheet, FIG. 3 is a sectional view showing another embodiment, and FIG. 4 is a sectional view showing an example of a conventional product. DESCRIPTION OF SYMBOLS 1...Surface layer, 10...Oil-resistant rubber layer, 11...
... fiber layer, 2 ... reinforcing layer, 20, 20 ... fiber lining layer, 3 ... compressible layer, 30 ... elastic sheet,
31...Minute through hole, A...Compressible offset blanket.

Claims (1)

[Claims for Utility Model Registration] 1. A compressible offset blanket comprising a compressible layer between a surface layer and at least one reinforcing layer, in which the compressible layer is bent into an uneven cross-sectional shape. A compressible offset blanket comprising a sheet. 2. The compressible offset blanket according to claim 1, wherein the pitch of the convex portions of the elastic sheet is 10 to 100μ. 3. The compressible offset blanket according to claim 1, wherein the surface layer has a single layer structure of an oil-resistant rubber layer. 4. Claim 1 of the above utility model registration wherein the surface layer has a two-layer structure consisting of an oil-resistant rubber layer and a fiber layer.
Compressible offset blanket as described in Section 1.