JPH0318210Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field This invention relates to a compression offset blanket. More particularly, the present invention relates to a compression 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) 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 object of this invention is to provide a compressible offset blanket that can solve the problems described above 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 formed between a surface layer and at least one reinforcing layer, the compressible layer is , which is characterized by being constructed of an elastic sheet made of a rubber sheet and having numerous minute through-holes passing through it vertically.

<Example> Next, an example of this invention will be described below with reference to FIGS. 1 and 2.

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. Reference numeral 22 denotes a reinforcing layer, in which an intermediate magnetic rubber layer 21 is interposed between rubberized fiber backing layers 20 and 20'.

3 is 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 an elastic sheet 30 in which countless minute through-holes 31 penetrating vertically are uniformly distributed. It is configured. This elastic sheet 30 has a thickness of about 0.2 to 1 mm, JIS
A rubber sheet with a hardness of 40-70 is used. Further, the micro through holes 31 are uniformly perforated on the entire surface by various means such as laser beam irradiation, jet water jetting, shot blasting, and needle punching, and the hole diameter is preferably 10 to 100 μm. Approximately 60μ and a forming pitch interval of approximately 10 to 100μ are suitable.

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 reinforcing layer 2 may also include at least one layer of the fiber backing layer 20. Bye.

<Specific example> The compressed layer 3 of the blanket A described above is made of
It is made of a rubber sheet formed into a 10 cm thick rubber sheet, and when tested by attaching it to 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. The so-called "thickening phenomenon" in which the diameter of the point becomes thicker by a predetermined diameter does not occur, and
The so-called "blank phenomenon" where spots appear in each halftone dot
Furthermore, it was confirmed that extremely good printed images could be obtained, with no striped shading called "shock marks" that appear on the printing screen due to the clearance between the gears of the printing roller.

If the diameter of the minute through-holes 31 is less than 10μ, the compressibility (elasticity) will be insufficient, resulting in thick dots and shackle, while if it is more than 100μ, it will be too soft, resulting in lack of clarity and sharpness of the image. However, by appropriately selecting the formation pitch of the minute through holes 31 and the hardness of the elastic sheet 30, it is possible to eliminate these disadvantages.

<Effects> According to the compressible offset blanket of this invention constructed as described above, since the compressible layer is constituted by an elastic sheet having countless minute through-holes that pass through it vertically, the aforementioned minute through-holes It is possible to obtain a very good printed image with sharp halftone dots, no thickening, no blank spots, and no shackle.

In particular, it is easy to form minute through holes in a uniform distribution, and a uniform printing pressure can be generated over the entire surface of the blanket, resulting in a better printed image.

Furthermore, the compressible layer itself can be formed easily and at low cost, thereby providing various excellent practical effects.

[Brief explanation of the drawing]

FIG. 1 is a sectional view, FIG. 2 is a perspective view of an elastic sheet, and FIG. 3 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... Reinforcement 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 compressed offset blanket comprising a compressible layer between a surface layer and at least one reinforcing layer, wherein the compressible layer is made of a rubber sheet and penetrates vertically. 1. A compressible offset blanket comprising an elastic sheet having countless minute through-holes. 2. The compressible offset blanket according to claim 1 of the above-mentioned utility model registration, wherein the minute through-holes have a diameter of 10 to 100μ. 3. Claim 1 of the above-mentioned utility model registration, in which minute through-holes are formed at a pitch of 10 to 100μ.
The compressible offset blanket according to item 1 or 2. 4. The compressible offset blanket according to claim 1, wherein the surface layer has a single layer structure of an oil-resistant rubber layer. 5. Claim 1 of the above utility model registration in which the surface layer has a double structure consisting of an oil-resistant rubber layer and a fiber layer.
Compressible offset blankets as described in Section.