JPH05200970A - Manufacturing of plate cylinder for printing machine - Google Patents

Abstract

PURPOSE:To eliminate troubles arising from slippage of a plate without interposing a plastic sheet between the plate and a plate cylinder or placing plate-fixing springs between the end of the plate and the plate cylinder, and to improve corrosion resistance. CONSTITUTION:The surface roughness of a plate cylinder 1 is adjusted to become 1.0mum<=100mum, and thereby minute unevenness is formed to the surface and then plating is applied thereto to form a plating layer 7. As minute dimples are formed over the surface of the plating layer 7 as a result of the above- mentioned processes, friction coefficient between the plate cylinder and a plate can be improved greatly. As Cr plating crystals over the minute dimples develop radially and adjoining crystals interfere one another, defects in the final plating layer are decreased, resulting in improvement of corrosion resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a plate cylinder used in an offset rotary printing press or the like.

[0002]

2. Description of the Related Art The plate cylinder of a conventional offset rotary printing press is
From the viewpoints of corrosion resistance, abrasion resistance, stain removability, etc., the surface of the plate cylinder is plated with Cr and then polished to adjust the surface roughness to Rmax <1.0, or the food material is used as meat. It is used after being welded and then polished. Further, there is also one that improves the coefficient of friction with the plate by adjusting the surface roughness of the plate cylinder.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
I had the following problem. That is, FIG. 4 shows a case where the plate 2 is mounted on the plate cylinder 1 and printing is performed. In this case, the printing pressure P is applied to bring the plate cylinders 1 and 2 into contact with the blanket cylinder 3 and rotate them. At this time, the plate cylinder 1 and the blanket cylinder 3
If there is a difference in circumferential length between the plate and the plate, the tangential force F acts on the plate 2 mounted on the plate cylinder 1.

Therefore, the tangential force F causes a minute slip between the plate 2 and the plate cylinder 1 corresponding to the above-mentioned difference in circumferential length, and the slip is accumulated as the printing operation proceeds, and the plate 2 and the plate 1 are accumulated. There was a so-called misregistration trouble in which the relative position to the body 1 changed. As a measure for preventing this plate misalignment trouble, (1) as shown in FIG. 5, a plastic sheet 4 called a lumirror is interposed between the plate 2 and the plate cylinder 1,
(2) Alternatively, as shown in FIG. 6, the spring force of the plate fixing spring 5 interposed between the plate cylinder 1 and the end of the plate 2 is strengthened.

However, in the case of the above (1), since the plastic sheet 4 is interposed between the plate 2 and the plate cylinder 1, it is inefficient in work. Further, in the case of the above (2), it is difficult to completely eliminate the misregistration trouble in addition to increasing the power for operating the spring. The present invention is proposed in view of the above problems, and an object thereof is to provide a plate cylinder and an end portion of the plate without a plastic sheet interposed between the plate and the plate cylinder. Even if no plate fixing spring or the like is interposed, the plate misalignment trouble can be solved. Another object is to provide a method of manufacturing a plate cylinder for a printing press, which can improve corrosion resistance.

[0006]

In order to achieve the above object, a method of manufacturing a plate cylinder for a printing machine according to the present invention comprises adjusting a surface roughness of the plate cylinder to 1.0 μm ≦ 100 μm, and then forming a plating layer. Is formed.

[0007]

In the method for producing a plate cylinder for a printing machine of the present invention, the surface roughness of the plate cylinder is adjusted to 1.0 μm ≦ 100 μm as described above to form the fine irregularities, and then the plating layer is formed.
The surface of the plating layer becomes fine dimples, and the coefficient of friction with the plate is significantly improved. In addition, the growth of the Cr-plated crystal on the minute uneven surface becomes radial and interferes with each other between adjacent crystals. As a result, the defects in the final plated layer are reduced and the corrosion resistance is improved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, FIG.
1 is a plate cylinder, and 6 is an intermediate plating layer formed on the surface of the plate cylinder 1. The intermediate plating layer 6 is finished and the surface roughness Rmax is adjusted to 1.0 μm ≦ 100 μm. For the plate cylinder 1 without the intermediate plating layer 6, the surface of the plate cylinder 1 is finished and the surface roughness Rmax is 1.0 μm ≦ 100 μm.
Adjust to.

Next, a final plating layer 7 is formed on the surface of the intermediate plating layer 6 (the surface of the plate cylinder 1 for the plate cylinder 1 without the intermediate plating layer 6). The final plated layer 7 is used as it is without any surface treatment such as polishing.
The surface roughness Rmax is set to 1.0 μm ≦ 100 μm in order to easily secure the processing accuracy. After the surface roughness Rmax of the plate cylinder 1 is adjusted to 1.0 μm ≦ 100 μm as described above, the final plating layer 7 is formed to increase the friction coefficient between the plate 2 and the plate cylinder 1. You can
As a result, the plate misalignment trouble can be eliminated and the plate cylinder 1 having excellent corrosion resistance can be obtained. That is, the final plating layer 7
1.0 μm ≦ Ra on the underlying surface of the plate cylinder 1 before forming
By forming minute irregularities of about x ≦ 100 μm,
There is a difference in micro-electrodeposition conditions on the final plating layer 7 surface,
The surface of the final plating layer 7 becomes fine dimples,
The coefficient of friction with the plate 2 is significantly improved. Further, the growth of the Cr-plated crystal on the minute uneven surface becomes radial and interferes with each other between the adjacent crystals. As a result, the final plated layer 7
The defects inside are reduced and the corrosion resistance is improved.

Next, specific examples (1) to (3) will be described.
(1) A Cr plating layer (intermediate plating layer) having a thickness of 100 μm is formed on the surface of the mild steel plate cylinder 1, and then sandblasting is performed to adjust the surface roughness Rax≈3 μm, and then the surface roughness Rax≈30 μm. A re-Cr plating layer (final plating layer) is formed, (2) A Cr plating layer (intermediate plating layer) having a thickness of 70 μm is formed on the surface of the mild steel plate cylinder 1, and then a surface roughness Ra is obtained by sandblasting.
x≈6 μm, then surface roughness Rax≈30 μm
With a re-Cr plating layer (final plating layer)
(3) Surface roughness Rax is formed on the surface of the mild steel plate cylinder 1 by sandblasting without forming an intermediate plating layer.
The friction coefficient with the plate 2 was measured by adjusting the thickness to 6 μm and then forming a re-Cr plating layer (final plating layer) having a surface roughness Rax of 30 μm. Further, the coefficient of friction with the plate 2 was also measured for a conventional Cr plating layer having a plating thickness of 130 μm and then polished, and the respective results are shown in FIG. Further, the corrosion resistance of the specific example (2) and the corrosion resistance of the conventional product were measured, and the respective results are shown in FIG. The corrosion resistance in FIG. 3 is obtained by standardizing the time until rusting by the salt spray test with the time until rusting of the conventional product.

[0011]

As described above, the method for manufacturing a plate cylinder for a printing machine of the present invention adjusts the surface roughness of the plate cylinder to 1.0 μm ≦ 100 μm to form fine irregularities, and then a plating layer (final plating). Layer), the surface of the plating layer becomes fine dimples, and the coefficient of friction with the plate is significantly improved. Therefore, the plate misalignment trouble can be solved without interposing a plastic sheet between the plate and the plate cylinder or without interposing a plate fixing spring or the like between the plate cylinder and the end of the plate. ..

Further, since the growth of the Cr-plated crystal on the minute uneven surface becomes radial and the adjacent crystals interfere with each other, defects in the final plated layer can be reduced and the corrosion resistance can be improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing an embodiment of a method for manufacturing a plate cylinder for a printing machine according to the present invention.

FIG. 2 is an explanatory diagram comparing a friction coefficient between a plate cylinder obtained by the manufacturing method and a conventional plate cylinder with respect to a plate.

FIG. 3 is an explanatory diagram comparing the corrosion resistance of a plate cylinder obtained by the same manufacturing method and a conventional plate cylinder.

FIG. 4 is an explanatory view showing a problem of a conventional plate cylinder.

FIG. 5 is an explanatory view showing an example of a conventional misregistration trouble prevention measure.

FIG. 6 is an explanatory diagram showing another example of a conventional misregistration trouble prevention measure.

[Explanation of symbols]

 1 plate cylinder 2 plate 6 intermediate plating layer 7 final plating layer Rax surface roughness

Claims (1)

[Claims] 1. The surface roughness of the plate cylinder is 1.0 μm ≦ 100 μm.
A method for producing a plate cylinder for a printing press, which comprises forming a plating layer after adjusting to m.