JPH0665800A - Electrolyzer for planographic printing plate support - Google Patents

Abstract

PURPOSE:To provide an electrolyzer for planographic printing plate support in which electrodes are exchanged in a short time at a low cost. CONSTITUTION:Small columnar electrodes 3c and 3d are used as the main electrodes, the axis of the electrode is directed at right angles to the traveling direction of a metallic web 1, and an insulator is not needed between the electrodes. The electrode 3c is connected to one side of a DC power source 7 and the electrode 3b and auxiliary electrode 8 to the other side. The electrodes 3c and 3d are directly attached or detached to and from the side plate of the electrolyzer, and a drum roller 2 need not be attached or detached when the electrodes are exchanged. The liq. sealing is facilitated by an O ring, etc., because the electrodes 3c and 3d are columnar. The time to exchange the electrodes is reduced to 4/18 and the labor to 20%. Further, since the electrode is columnar, a planographic printing plate support excellent in plate wear resistance due to the good surface-quality composite grains free of chatter marks is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic treatment apparatus, and is particularly suitable for roughening and anodizing treatment of a metal web for a lithographic printing plate by an alternating waveform current, and particularly for a offset printing plate. The present invention relates to an electrolytic treatment device for a support for a lithographic printing plate, which is made of a materialized aluminum plate.

[0002]

2. Description of the Related Art Aluminum plates are used as a support for printing plates, especially a support for lithographic printing plates. Due to the diversification of users, aluminum plates are similar to pure aluminum. It is diversified up to the raised one. In order to use such an aluminum plate as a support for a lithographic printing plate, it is necessary to have appropriate adhesiveness to a photosensitive material and water retention.

For this purpose, the surface of the aluminum plate must be roughened so as to have uniform and fine grain. This roughening treatment significantly affects the printing performance such as the stain performance of the plate material when printing is actually performed, and the quality thereof is an important factor in the plate material manufacturing.

The roughening treatment is performed by mechanical roughening,
Methods and apparatuses for chemical surface roughening and electrochemical surface roughening are used. Among them, as an apparatus for electrochemical surface roughening and anodizing treatment, a metal web is used in an electrolytic treatment liquid containing metal ions. There is used an electrolytic treatment apparatus for a lithographic printing plate support which supplies an alternating current between the metal web and an electrode facing the metal web to continuously perform an electrochemical treatment on the metal web. (JP-A-2-15198, Japanese Patent Application No. 4-313)
As shown in FIG. 4, in the conventional electrolytic treatment apparatus, the metal web 1 as the material to be treated is supported by the circumference of the drum roller 2 and the space between the opposing main electrodes 3a and 3b. Is filled with the electrolytic treatment liquid 5 containing metal ions from the electrolytic solution supply port 4 and discharged from the electrolytic solution discharge port 6, whereby the electrolytic solution passage 1
Set to 3. The main electrode 3a, 3b is an electrolytic treatment apparatus for supplying an alternating waveform current from an AC power supply 7 to perform an electrochemical treatment, and a counter electrode with the metal web 1 is formed by the main electrode 3a, 3b and an auxiliary electrode 8. A diode for connecting the circuit for the auxiliary electrode 8 in parallel to the circuit connected to the main electrodes 3a, 3b, and for connecting the circuit in the main counter electrode of the anode current in parallel to control the flow of the anode current in the main electrode. 9 or the auxiliary electrode 8 having a mechanism that acts like a diode.
Is an electrolytic treatment device which is provided in a circuit for supplying a current.

In this case, the main electrodes 3a and 3b have polarities opposite to each other, and are connected to the AC power supply 7 on opposite sides, and the main electrodes 3a and 3b each have a large number (for example, n = 10). ~ 14) small electrodes (3a ₁ , 3a ₂ , 3)
_{a 3 ··· 3a n) (3b} 1, 3b 2, 3b 3 ··· 3
b _n ) are formed with the insulator 10 as a boundary, and are devised to increase the current efficiency.

[0006]

However, in the conventional electrolytic treatment apparatus, prismatic carbon electrodes are used as the small electrodes 3a and 3b. The electrode of the electrolytic treatment apparatus is very susceptible to deterioration due to the use of alternating current.For example, when carbon is used as the electrode, the oxidation-reduction reaction is repeated due to the change in polarity, and the binder is severely deteriorated. I have to.

In the case of replacing the electrodes, as shown in FIG. 3, first, the drum roller 2 is lifted up and taken out from the upper opening,
For each small electrode 3a, 3b, the fixing nipple 11 is first removed from the small electrode 3a, 3b, and then the small electrode is lifted and removed from the upper opening of the electrolytic treatment apparatus. However, there is a problem that the cost for replacement is high.

It is an object of the present invention to solve the conventional problems, and to provide an electrolytic treatment apparatus for a lithographic printing plate support, in which electrode replacement is completed in a short time and replacement costs are low.

[0009]

The above object of the present invention is to provide an electric current between the metal web and an electrode facing the metal web in an electrolytic treatment solution containing metal ions to supply the electric current to the metal web. In the electrolytic treatment apparatus for a lithographic printing plate support that is continuously subjected to electrochemical treatment, the main electrode facing the metal web has a columnar shape, and the axis of the columnar shape is in the traveling direction of the metal web. This is achieved by an electrolytic treatment apparatus for a lithographic printing plate support, which is arranged at a right angle, and the main electrode can be attached to and detached from the electrolytic treatment apparatus in the axial direction of the main electrode.

In the present invention, the cylindrical shape of the electrode facilitates attachment / detachment of the electrode in the axial direction, and facilitates complete liquid sealing of the attachment / detachment portion of the electrolytic treatment apparatus. Therefore, the line down time for replacement can be greatly shortened, and the replacement cost can be reduced.

An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is the same as that described in FIG. 4 except that the main counter electrode is omitted. In the case of FIG. 1, each of the small electrodes 3c and 3d serving as the main counter electrode has a columnar shape, and the axis of the columnar shape is arranged at right angles to the traveling direction of the metal web 1, and the insulator 10 between the respective main electrodes is unnecessary. . The small electrode 3c is connected to one side of the AC power supply 7, and the 3d and the auxiliary electrode 8 are connected to the other side of the AC power supply.

As shown in FIG. 2, the small electrode electrolytic treatment apparatus can be directly attached to and detached from the side plate of the electrolytic treatment apparatus.
There is no need to remove or attach the drum roller 2. The liquid sealing is easy because the small electrodes 3c and 3d have a circular columnar shape, and is performed by, for example, an O-ring 12. Further, since the fixing nipple 11 is also attached to the small electrode (main counter electrode), there is no need to remove it for replacement.

[0013]

【Example】

(Embodiment 1) As shown in FIG. 1, the small electrode of FIG. 4 was changed from a conventional prismatic column to a columnar shape, and an electrolytic treatment apparatus which was detachable in the axial direction was used. 1000mm, processing speed: 15m / min,
Electrolyte flow: 2,500 l / min, Clearance between web and counter electrode: 10 mm, Main electrode: carbon, Auxiliary electrode: Platinum, the same specifications as above, but the construction time for electrode replacement with the conventional device shown in FIG. When compared with the replacement cost, the conventional apparatus required 18 hours as the construction time, whereas the apparatus according to the present invention completed in 4 hours, and the replacement cost was about 20% of that of the conventional apparatus. I was able to do it.

(Example-2) Using the apparatus of the present invention shown in Example-1 and the conventional apparatus, the electrolytic solution conditions were as follows: nitric acid solution concentration 1%, solution temperature 40 ° C, electricity quantity 200 c / dm ² . Table 1 shows the results of electrolytic etching treatment using an alternating waveform current.

[0015]

[Table 1]

As shown in Table 1, (1) In the electrolytic treatment using an alternating waveform, the use of a cylindrical electrode causes soft start at each electrode, so that chatter marks are eliminated and the surface quality is improved. I was able to obtain the excellent one. (2) Since the distance between the aluminum support and the electrode changes depending on the circle of the cylindrical electrode, it can be seen that the distribution of current can be changed and a composite grain can be easily formed.

[0017]

As the main electrode of the present invention has a cylindrical shape and can be attached and detached in the axial direction, the time and labor for electrode replacement can be remarkably reduced, and the cylindrical small electrode has a good surface without chatter marks. It was possible to obtain a lithographic printing plate support having excellent printing durability due to the composite grain of surface quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of an electrolytic treatment apparatus for a lithographic printing plate support according to the present invention.

FIG. 2 is a partial front view of an embodiment of a mounting state of small electrodes of the electrolytic treatment apparatus of the present invention.

FIG. 3 is a partial front view of an example of an attached state of small electrodes of an electrolytic treatment apparatus for a conventional lithographic printing plate support.

FIG. 4 is a cross-sectional view of an example of a conventional electrolytic treatment apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal web 2 Drum rollers 3a, 3b Main electrode (conventional) 3c, 3d Main electrode (of the present invention) 4 Electrolyte solution inlet 5 Electrolysis treatment solution 6 Electrolyte solution outlet 7 AC power supply 8 Auxiliary electrode 9 Diode 10 Insulator 11 Fixing nipple 12 O-ring 13 Electrolyte passage

Claims (1)

[Claims] 1. A lithographic printing plate in which an electric current is supplied between a metal web and an electrode facing the metal web in an electrolytic treatment liquid containing metal ions to continuously perform an electrochemical treatment on the metal web. In the electrolytic treatment apparatus for a supporting body, the main electrode facing the metal web is formed into a columnar shape, and the axis of the columnar shape is arranged at a right angle to the traveling direction of the metal web. An electrolytic treatment apparatus for a lithographic printing plate support, wherein the main electrode is removable in the axial direction of the main electrode.