JPS5856855A - Mesh roll for offset printing - Google Patents

Abstract

PURPOSE:To prevent the density of an ink from being lowered due to water, by a method wherein the peripheral surface of a steel made roll subjected to mesh working is uniformly plated with chromium, a porous layer is produced at a surface layer part of the plated chromium, and an oil is infiltrated into the porous layer to provide an oleophilic property to the latter. CONSTITUTION:The peripheral surface of the steel-made roll 4 is subjected to mesh working to produce recesses 9 and a net form projected surface 22, the surfaces of the recessed and projected parts are uniformly plated with chromium to produce a plated chromium layer 23, and the surface of the plated layer 23 is made to be porous by treating the surface layer part of the layer 23. Then, the surface of the porous layer is made to be oleophilic by infiltrating an oil into the porous layer, resulting in a surface which has high affinity for ink but repellent to water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes a Mency roll (also known as amiroll, screen trol or anilox roll), which has been conventionally developed as an ink supply system for 6-wheel, especially 7-wheel printing, for offset printing. Concerning a special mesh roll modified to obtain.

It is well known that the use of mesh rolls eliminates the need for a large number of ink cylinders. Therefore, if this mesh roll could be introduced into offset printing, it would be possible to make the offset printing mechanism smaller, lighter, simpler and cheaper. This will be of irreplaceable benefit to the small and medium-sized printing industry, which operates with limited space and little capital.

The inventor has made numerous tests to solve the above problem.
1- As a result of repeated efforts, the following difficult problems were discovered: (1) Although the benefit of eliminating the need for a large group of ink cylinders was, on the other hand, the return water generated from the water supply, which is a mold in offset printing, was removed from the plate cylinder surface by the ink forming roll. (2) Since the chromium layer of the chrome-plated mesh roll is hydrophilic, water drives away the ink on the roll and flows back onto the roll. It was found that the density of the ink that reaches the printed paper surface becomes thinner, and clear printing is obstructed.Therefore, there was an urgent need to find a technical solution to this problem.

The purpose of the present invention is to solve the above-mentioned problems and create a mesh roll exclusively for offset printing that can prevent the deterioration of ink coverage on the mesh roll surface due to water and smoothly supply ink to the plate cylinder surface. and provide it.

To summarize the concept of the present invention, mesh-like unevenness is machined on the circumferential surface of a steel roll, the unevenness is uniformly covered with a chrome plating layer, and a porous layer is formed on the surface of the chrome plating layer. The method is to form a lipophilic layer by impregnating the porous layer with oil, or by uniformly covering the mesh-like uneven portion with a ceramic layer and applying a large number of pins in the second ceramic layer. There is a point tζ at which the hole is impregnated with oil to form a lipophilic layer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and operation of the present invention will be described in detail below with reference to the drawings according to one specific embodiment.

FIG. 1 shows an example of the basic form of an offset printing system in which a mesh roll 4t is arranged. When ink 6 in an ink pan 5 is taken out by a fountain roll 7 and the ink is transferred to the mesh roll 4, the surface of the roll 4 is On the other hand, the ink on the surface of the roll number is scraped off by the doctor blade 8, which comes into contact with the roll in a position opposite to the direction of rotation (reverse angle), so that a large number of ink adheres to the roll 4, as shown in Fig. 2. A detailed example of 2
The ink in the recesses so limited is limited to those within the recesses 9 having a size of 50 meshes, and the ink within the recesses so limited is 7 ohm roll 1.
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and is supplied to the plate cylinder 11. 12 is a plancher in contact with the plate cylinder, 13 is an impression cylinder, and 14 is a running paper for printing.

On the other hand, the swimsuit roll 15 is in contact with the plate cylinder 11, and the roll is in contact with the swinging roll 16, while the water 18 in the water reservoir 17 is being transferred to the brush installed in the water base roller 19. A small amount is taken out by the brush 20, and the brush 20 is removed by the blade 2.
Water droplets are supplied onto the rocking roll 16 by the repulsive force bent by 1.

In such an offset printing mechanism, water is supplied onto the surface of the printing cylinder 11 by the roll 15 and then circulates to the mesh roll 4 via the 7-ohm roll 1 (Ii).

In order to withstand frictional contact with the blade, the conventional mensch roll is coated uniformly with wear-resistant chrome, including the recesses 9T- on its circumferential surface.

However, since chrome is a highly hydrophilic material, it absorbs water better than ink, so once water adheres to the mesh roll surface, the ink is repelled, making it difficult for the ink to be properly supplied. will arise.

Accordingly, in the first aspect of the present invention, after forming mesh-like uneven portions, that is, recesses 9 and protruding surfaces 22 on the circumferential surface of the steel roll 4, the surface of the uneven portions is uniformly stamped. A chrome plating layer 231 is formed, and its surface layer is further subjected to porous processing to make the plating surface porous.

Mechanical processing called knurling type and electrolytic etching are well known for porous processing of the surface layer of chromium plating, and these methods can be effectively utilized to form the porous layer 23a (first layer) with fine pores in the surface layer. (see Figure 4), and the porous layer is impregnated with oil.

Chromium is originally hydrophilic and non-oleophilic, but by processing the surface of the oil-impregnated porous layer 23a'ji, it becomes lipophilic, blends well with ink, and repels water.

If the protruding surface 22 of the roll 4 lacks smoothness due to porous processing, polishing the surface to make it smooth will allow close contact with the doctor blade 8 and ensure sufficient ink scraping.

In the second aspect of the present invention, after processing the mesh-like uneven portions 9 and 22t on the circumferential surface of the steel roll 4, the surface of the uneven portions is uniformly coated with ceramic by plasma welding to form a ceramic layer 241. make it.

As is well known, ceramic has countless pinholes 24.
Since a is present, it is subjected to oil impregnation treatment.

Ceramic is inherently hard and has excellent abrasion resistance, so we took advantage of its key points and impregnated the pinholes with oil to give it lipophilic properties, creating a base that is compatible with ink. adhesion is eliminated.

Since the protruding surface 22 of the roll number lacks smoothness, if the surface is well polished to ensure close contact with the doctor blade 8, the ink scraping effect will not be reduced in the slightest.

Since the present invention has the above-mentioned structure and operation, the main purpose is to provide durability by utilizing chromium and ceramic T, which have excellent wear resistance, and to provide porous processing to the surface layer. By treating it with oil, we succeeded in creating a highly oleophilic surface over the entire circumference of the roll, which completely repelled water and ensured a smooth and sufficient supply of ink toward the plate cylinder. I started getting it.

[Brief explanation of the drawing]

Figure 1 of cylinder is an explanatory diagram showing an example of an offset printing system using a mesh roll according to the present invention. FIG. 2 is a partially enlarged view of the circumferential surface of the meshi roll according to the present invention. Figure 3 is a further enlarged partial sectional view taken along the line 3-3 in Figure 2, Figure 4 is a further expanded partial sectional view of the surface layer portion in the first aspect of the present invention, and Figure 5 is a further expanded partial sectional view of the surface layer in the second aspect of the present invention. FIG. 2 is a further enlarged partial cross-sectional view of the surface layer in FIG. 4... Metschroll, 8... Reverse angle doctor blade, 9...
Recess, 22... Projection surface, 23... Chrome plating layer, 23 a... Porous layer. 24... Ceramic layer, 24 a... Countless pinholes. Patent applicant Tokyo Kikai Seisakusho Co., Ltd. Patent attorney
Shigeru Sanne, Patent Attorney, Shigeru Sanne
Mamoru figure 1

Claims (1)

[Claims] 11) A mesh-like uneven portion processed on the curved surface of a steel roll, a chrome plating layer covering the uneven portion, and a porous layer formed on the surface of the chrome plating layer. A mesh for offset printing, an o-le, comprising: a lipophilic layer in which a porous layer is impregnated with oil; (2) A mesh-like uneven part processed into the surface of a steel roll, a ceramic layer covering the uneven part, and an oleophilic layer impregnated with oil in a large number of pinholes in the ceramic layer. Equipped with a mensch roll for offset printing.