JPH0457757B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for uniformly applying copper plating to the entire surface of a gravure printing cylinder.

<Conventional technology> This type of conventional technology is as shown in Figure 6.
In this method, the gravure printing cylinder 1 was completely immersed in an acidic copper sulfate aqueous solution in a separate plating apparatus, and copper plating was performed at high current density while rotating at high speed.

However, in the method shown in FIG. 6, the current 3 from the anode 2 concentrates on both ends of the gravure printing cylinder 1, causing burnt areas, dendritic plating, or the plating film. A defect occurred in which the thickness became extremely thick in some parts.

The above-mentioned defects were particularly likely to occur in the gravure printing cylinder 1 which had a small diameter and a short length.

Therefore, in order to improve these defects, conventional methods have been to lower the current density, adjust the amount of additives, or add copper wire to the waterproof caps of the conductive adapters 4 set at both ends of the gravure printing cylinder 1. Methods such as wrapping the

In addition, as a device for adjusting the plating thickness applied to both ends of a cylinder for gravure printing, there is a device developed by one of the applicants for this patent.
Publication No. 19169 is publicly known.

As shown in FIG. 7, this known technique involves attaching plating thickness adjustment masks 6 near both ends of the gravure printing cylinder 1 when copper plating 11 is applied to the gravure printing cylinder 1. This is intended to adjust the thickness of the copper plating 11 plated on both ends of the printing cylinder 1.

<Problems to be Solved by the Invention> However, among the above-mentioned conventional techniques, the method of lowering the current density is contrary to the purpose of speeding up plating, and the above-mentioned defects cannot be solved by lowering the current density to some extent. It was not done.

In addition, the method by adjusting additives is also available at 10A/dm ²
Although it is effective to some extent at current densities below, it cannot cope with current densities higher than that.

The method of winding copper wire has some effect up to a current density of about 20 A/dm ² , but at higher current densities, the above-mentioned defects begin to occur.

Furthermore, attaching and detaching the copper wire is extremely complicated and time-consuming, and the dendrites formed on the copper wire are likely to fall off in the plating bath, so it is difficult to avoid bumps and pits in the plating film. There were also some drawbacks.

Furthermore, when using the plating thickness adjusting device in which the plating thickness adjusting masks 6 are provided near both ends of the gravure printing cylinder 1 shown in FIG. 7,
As shown in FIG. 7, since the current 3, which has delicate pressure and flow, cannot be adjusted, the copper plating 11 at the center of both ends becomes thin, and the copper plating 11 at the corners around it becomes thin. The problem was that the wall was thick and the plating was extremely uneven as a whole.

The copper plating method for gravure printing cylinders according to the present invention is a completely newly developed technology to fundamentally improve the above-mentioned conventional drawbacks, and is particularly uniform over both ends of the gravure printing cylinder. The purpose of the present invention is to provide a technology that allows easy electrodeposition of copper plating having a film thickness of about 100 to 100%.

<Means for Solving the Problems> The copper plating method for gravure printing cylinders according to the present invention is a technology that fundamentally improves many of the conventional problems described above, and its gist is In this method, a gravure printing cylinder is fully immersed in a cylinder and the surface is plated with copper while rotating.A shielding plate made of a material such as rubber or resin that does not conduct electricity and has holes of various sizes drilled therein is used. By attaching it near both ends of the gravure printing cylinder, copper plating is applied to the entire surface of the gravure printing cylinder while freely adjusting the amount of current applied to both ends of the gravure printing cylinder. This is a copper plating method for gravure printing cylinders.

<Function> As described above, in the copper plating method for a gravure printing cylinder according to the present invention, shielding plates made of non-energized rubber, resin, etc. with holes of various sizes are placed on both sides of the gravure printing cylinder. Since it is attached near the end, the shielding plate blocks most of the current that tends to concentrate on the outer periphery of both ends of the gravure printing cylinder when electrodeposition is applied to the entire circumferential surface of the gravure printing cylinder. I can do it.

In addition, only a portion of the current is allowed to reach both end surfaces of the gravure printing cylinder through large and small holes in the shielding plate, thereby adjusting and making the distribution of the current flowing over the entire both end surfaces of the gravure printing cylinder uniform. It is possible to apply uniform copper plating to a predetermined thickness.

〈Example〉 The process of carrying out an embodiment of the copper plating method for gravure printing cylinders according to the present invention will be explained with reference to the drawings. Fig. 1 shows a side view of the state in which the method of the present invention is carried out. Figure 2 is a front view of the shielding plate, Figure 3 is a side view of a shielding plate with a dog-shaped cross section, Figure 4 is a side view of a cylindrical shielding plate, and Figure 5 is a side view of a shielding plate with a cylindrical shape. FIG. 3 is a side explanatory diagram showing the flow of current when the method of the present invention is implemented.

Referring to FIGS. 1 and 2, the apparatus for carrying out the method of the present invention will be described as follows.

1 is a cylinder for gravure printing, which is immersed in an acidic copper sulfate bath (not shown). Reference numeral 2 denotes an anode, which is arranged on both the upper and lower sides of the gravure printing cylinder 1.

A current 3 flows out from these anodes 2 to the gravure printing cylinder 1, and the current 3 transmitted to the gravure printing cylinder 1 is collected by a conductive adapter 4.

Reference numeral 5 denotes a disc-shaped shielding plate, which is made of a resin plate or a rubber plate that does not conduct electricity;
A large number of holes 5a of different sizes are bored in the hole.

The shape of the hole 5a of this shielding plate 5 is round, rectangular,
Any shape such as a triangle or star shape may be used, but a round shape is most effective in terms of ease of drilling.

Further, the size, number, and position of the holes 5a may be changed depending on the diameter of the gravure printing cylinder 1 to be plated, but as shown in FIG. It is more effective to form a plurality of large holes 5a and make the holes 5a smaller as the distance from the conductive adapter 4 increases. In reality, actual plating is performed and the number of holes 5a in the shielding plate 5 is increased or decreased until the total film thickness on the outer surface of the gravure printing cylinder 1, including both end surfaces of the gravure printing cylinder 1, approaches a constant value. method is adopted.

In the above embodiment, the shielding plate 5 is formed of a disk, but as shown in FIG. 3, it is also possible to use a shielding plate 5 whose cross-sectional shape is bent into a dogleg shape. It is.

When this dogleg-shaped shielding plate 5 is used, the outer circumferential portion of the shielding plate 5 is close to the outer circumferential surface of both ends of the gravure printing cylinder 1.
The accuracy of plating film thickness can be improved.

Furthermore, as shown in FIG. 4, a cylindrical shielding plate 5 can also be used.

Further, the shielding plate 5 may be attached to the conductive adapter 4 so as to be slidable, or may be attached so that it can be attached and detached with a single touch.

Next, one embodiment of the method according to the present invention will be specifically described as follows.

The composition of the soaking bath used in the examples and comparative rows was copper sulfate 230g/1, sulfuric acid 70g/1, and chlorine ions.
100mg/1, Nihon Kagaku Sangyo Co., Ltd. Additive Boomerite '84-MP4m1/1, Boomerite '84-
A1.2m1/1, Boomerite'84-B4m1/1. The rotation speed of gravure printing cylinder 1 is
120 rpm, the size of the gravure printing cylinder 1 is 900×152.5φmm.

A specific example will be explained using the shielding plate 5 shown in FIGS. 3 and 5. The shielding plate 5 having a dogleg-shaped cross section and having holes 5a as shown in FIGS. 3 and 5 is used as a cylinder for gravure printing. When copper plating was carried out at 45°C and 30 A/dm ² for 15 minutes and 50 seconds, a current 3 flowing out from the anode 2 toward both ends of the gravure printing cylinder 1 is the fifth
As shown in the figure, most of the current is shielded by the shielding plate 5, but a part of the current passes through the hole 5a and reaches both ends of the gravure printing cylinder 1, and the current flows through the entire both ends. Uniform copper plating 11 could be applied.

Therefore, the copper plating 11 having uniform gloss could be applied to the entire outer circumferential surface of the body of the gravure printing cylinder 1 and the entire outer surface of both end portions.

In addition, copper plating 11 could be performed on both ends of the gravure printing cylinder 1 without any occurrence of burnt or resin deposits.

Furthermore, the film thickness of the copper plating 11 of the gravure printing cylinder 1 obtained in this example is 100 μm on average at both side ends, and the film thickness at both side ends of the outer circumferential surface (printing surface) of the body is 100 μm on average. Both end portions (within 2 cm from the corner) that are continuous with each other were 102 μm on average, and the center portion of the outer peripheral surface of the body was 98 μm on average.

<Comparative Example> The following results were obtained when the method of the present invention was compared with the conventional method in which no shielding plate was used as shown in FIG. 6. .

That is, the method shown in Fig. 6 ^is carried out at 45℃, 30A/dm
When copper plating was carried out for 15 minutes and 50 seconds, the gloss of the copper plating 11 was good, but resin-like deposits were generated on both ends of the gravure printing cylinder 1.

In addition, the thickness of the copper plating 11 applied to the surface of the gravure printing cylinder 1 is 110 μm on average at both ends, and at both ends (within 2 cm from the corner) of the outer peripheral surface (printing surface) of the body. was 130 μm on average, and the center of the outer peripheral surface of the body was 85 μm on average.

Therefore, when comparing the case where this conventional method is implemented with the case where the method of the present invention is implemented, it is found that the film thickness at both ends of the body's outer circumferential surface of the gravure printing cylinder is It was found that the film thickness at the end portion and both end portions became considerably large, and both became significantly non-uniform.

As is clear from this comparative example, it has become clear that when the present invention is implemented, extremely better results can be obtained than when the conventional method is implemented.

<Effects of the Invention> Since the method according to the present invention has the above-described configuration and operation, when copper plating is applied to a gravure printing cylinder, the current tends to concentrate on both ends of the gravure printing cylinder. can be dispersed or moderately blocked, thereby preventing burnt spots and dendritic breakouts from occurring on both ends of the gravure printing cylinder, and preventing the formation of burnt spots and dendritic breakouts on the entire surface of the gravure printing cylinder. It has the feature that the thickness of the copper plating applied to the surface can be made uniform.

[Brief explanation of drawings]

Fig. 1 is a side view of the state in which the method of the present invention is carried out, Fig. 2 is a front view of the shielding plate, Fig. 3 is a side view of the state in which a shielding plate with a dogleg-shaped cross section is used, and Fig. 4 is a cylindrical type. 5 is a side view showing the state in which the shielding plate is used, FIG. 5 is an explanatory side view showing the flow of current when the method of the present invention is implemented, FIG. FIG. 2 is an explanatory diagram of the second conventional example. 1... Cylinder for gravure printing, 2... Anode, 3... Current, 4... Conductive adapter, 5...
Shielding plate, 5a... hole, 6... plating thickness adjustment mask,
11...Metsuki.

[Claims]

1. A cylindrical rotating body having large-diameter parts at both axial ends, the outer peripheral surface of which is made of an insulating material, is installed in a processing tank that contains an electrolytic solution and serves as one electrode, and the large-diameter parts serve as a metal web. While rotating and supporting both widthwise sides of the metal web in an electrolytic solution, electricity is applied between the processing tank and the other electrode that constitutes the small diameter part of the rotating body to continuously electrolyze the metal web. A continuous electrolytic treatment device for metal webs. 2. The continuous electrolytic treatment apparatus for a metal web according to claim 1, wherein the insulating material is an elastic insulating material.