JPH05195300A - Electrolytic treating device - Google Patents

Abstract

PURPOSE:To provide the electrolytic treating device which is uniform and dense in sand dressing in the transverse direction of a metallic web, has high electrolysis efficiency and is effective for increasing line speed. CONSTITUTION:An electrolytic treating liquid 5 enters the inside of an electrolyte supply port 4 and enters the inside of a cavity 13 in such a manner that the liquid is uniformly distributed over the entire part in the transverse part of a radial drum roller 2 via a distributor 12. This liquid is ejected from a slit 14 into an electrolyte passage 15. Edge liquid feed nozzles 16a, 16b are provided respectively in each of main counter electrodes 3a, 3b in Fig. 1. The number of the edge liquid feed nozzles suffices if the nozzles are provided at >=2 points. The positions and structures of the edge liquid feed nozzles are not restricted. The structures may be round, square or slender. The position of the center of the edge liquid feed nozzles is preferably on the side inner by 50mm than both edges of the metallic web.

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 suitable for roughening and anodizing a metal web by an alternating waveform current, and in particular, an aluminum plate roughened for an offset printing plate. And an electrolytic treatment apparatus for a printing plate support.

[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, and manganese has Have been diversified. 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 has a significant influence on the printing performance such as the stain performance of the plate material when printing is actually performed, and therefore its quality is an important factor in plate material manufacture.

As a roughening method for the aluminum support for printing plates, there are a mechanical graining method, an electrochemical graining method, and the like, and the roughening is performed by appropriately combining them. There is. Mechanical graining methods include, for example, ball grain, wire grain, brush grain, and liquid honing method. An alternating current electrolytic etching method is generally adopted as the electrochemical graining method, and a normal sine wave alternating current or a special alternating waveform current such as a rectangular wave is used as the current. Further, as a pretreatment for this electrochemical graining, etching treatment may be performed with caustic soda or the like. Among them, the AC electrolytic etching method has a problem that the counter electrode due to carbon, metal, etc. is very likely to deteriorate unlike the phenomenon caused by the DC current. For example, when carbon is used as the counter electrode, the redox reaction is repeated each time the polarity changes, and the deterioration of the binder is severe and stable operation for a long period of time is extremely difficult.

To address such problems, Japanese Examined Patent Publication No. 61-48
No. 596, a circuit for the auxiliary counter electrode is connected to the circuit connected to the main counter electrode in parallel with the circuit for the auxiliary counter electrode, and a diode or a mechanism acting as a diode for controlling the flow of the anode current in the main counter electrode. There is disclosed an electrolytic treatment apparatus characterized by being provided in the.
For example, as shown in FIG. 3, a metal web 1 as a material to be treated is supported by the circumference of a radial drum roller 2, and a space between the opposing main counter electrodes 3a and 3b is connected to the metal from the electrolytic solution supply port 4 to form a space. The electrolytic solution 5 containing ions is replenished and discharged from the electrolytic solution discharge port 6 to fill it, thereby forming an electrolytic solution passage 15. An electrolytic treatment apparatus for supplying an alternating waveform current from an AC power source to the main counter electrodes 3a, 3b to perform an electrochemical treatment, in which the counter electrode with the metal web 1 is formed by the main counter electrodes 3a, 3b and the auxiliary counter electrode 8. , A circuit for connecting the auxiliary counter electrode 8 in parallel to the circuit connected to the main counter electrodes 3a, 3b, a circuit for connecting the anode current in the main counter electrode in parallel, and a diode 9 for controlling the flow of the anode current in the main counter electrode.
Alternatively, it is an electrolytic treatment apparatus in which a mechanism that acts as a diode is provided in the circuit for the auxiliary counter electrode 8 to flow an electric current. In this case, the main counter electrodes 3a and 3b have polarities opposite to each other,
The AC power supply 7 is connected to the opposite sides of each other, and the main counter electrodes 3a and 3b each have a large number (for example, n = 10 to 14).
Small electrodes of _{the) (3a 1, 3a 2,} 3a 3 ··· 3a n)
(3b ₁ , 3b ₂ , 3b ₃ ... 3b _n ) are configured with the insulator 10 as a boundary, and are devised to improve current efficiency.

[0005]

However, the electrolytic treatment solution 5 replenished from the electrolytic solution supply port 4 is the metal web 1
It flows toward the opposite side of the radial drum roller 2 through the narrow electrolyte passage 15 between the electrode 3a and the electrodes 3a, 3b, and while flowing out to the electrolyte discharge port 6, toward the edge of the radial drum roller with low resistance. Tend to flow to both edges of the metal web, which concentrates the treatment on both edges of the web, slowing the flow of the electrolytic solution in the central flow path, and electrolysis causes the electrolytic solution to gradually disappear. As a result of fatigue, the components of the electrolytic solution supply port 4 and the electrolytic solution discharge port 6 are different from each other, the treatment in the width direction of the metal web becomes uneven, and sufficient electrolytic efficiency is obtained in the electrolytic treatment apparatus as a whole. There was a problem that I could not do it. Further, the temperature difference between the electrolytic solution supply port 4 and the electrolytic solution discharge port 6 in the vicinity of the metal web was large, and desired grain could not be obtained. In particular, in the treatment liquid on the metal web 1 side in the electrolyte passage 15, the electrodes 3a, 3b of the electrolyte passage 15 are treated.
Insufficient mixing with the treatment liquid on the side, the degree of fatigue of the components and the difference in temperature are significant, resulting in uneven graining, that is, deterioration of electrolytic quality and deterioration of electrolytic efficiency. Therefore, in order to maintain a uniform and dense grain in the width direction of the metal web and to increase the electrolysis efficiency, a method of increasing the flow rate supplied from the electrolytic solution supply port 4 has been carried out. Not only does this lead to an increase in cost, but even if the flow rate is increased, the desired desired grain size could not be obtained. or,
The above-mentioned problem becomes remarkable when the length of the electrolytic treatment corresponding to the increase in the speed of the line is increased, and it has been a great limitation on the increase in the speed of the line.

An object of the present invention is to solve these problems of the prior art and to provide an electrolytic treatment apparatus in which the graining is uniform and dense in the width direction of the metal web, the electrolytic efficiency is good, and the line speed is increased. To provide.

[0007]

That is, the above object of the present invention is to provide an alternating waveform current between a metal web and a counter electrode in an electrolytic treatment solution containing metal ions to continuously supply the metal web. In an electrolytic treatment apparatus for performing an electrochemical treatment, a plurality of edge liquid supply nozzles are provided on both edges of the metal web from the main counter electrode side to the web. To be achieved. In the present invention, a plurality of edge liquid supply nozzles are provided to the web from both sides of the main counter electrode on both edges of the metal web, which means that the liquid supplied from the plurality of edge liquid supply nozzles is not A curtain film is formed on both edges to prevent the liquid in the central portion from flowing to both edges when there is no curtain film. As a plurality of edge liquid supply nozzles, a main counter electrode 3a,
It is preferable to install the same number as 3b, but when the amount of liquid supplied from the supply nozzle is large, the minimum number may be two. By the amount of the electrolyte supplied from the plurality of edge supply nozzles in the present invention, the electrolyte flowing outside the both edges of the metal web is sufficiently replenished, the flow velocity is increased, and the liquid discharged from the edge supply nozzle is used. Since the curtain film is formed, the electrolytic treatment solution replenished from the electrolytic solution supply port does not flow to both edges of the web but flows from the beginning to the end at a uniform flow rate over the entire width of the metal web. The metal web surface has more opportunities to come into contact with a fresh electrolytic treatment solution than before due to the mixing and stirring during circulation of the electrolytic treatment solution, the grain is even and dense, and the electrolytic efficiency as an electrolytic treatment apparatus increases, It is possible to increase the line speed.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the electrolytic treatment apparatus of the present invention. Reference numeral 1 is a metal web, and 2 is a radial drum roller that supports the web. The metal web 1 has main counter electrodes 3a, 3
The vehicle is traveling while maintaining a constant clearance between b and the auxiliary counter electrode 8. A clearance of 3 to 50 mm is usually suitable. The ratio of the main counter electrode and the auxiliary counter electrode differs depending on the electrolytic etching conditions to be obtained. 7 is an AC power supply, which is normally 0.
An AC power supply of 1 to 500 Hz is used. The frequency is changed depending on the etching pattern to be obtained, but if the frequency is 15 Hz or less, the main counter electrodes 3a and 3b are greatly deteriorated, particularly in the case of carbon. As a waveform,
There are various types, but Japanese Patent Publication Nos. 56-19280 and 5
It is also possible to use the special alternating waveform described in each publication of 5-19191. 9 is a diode, which allows
Controls the current flowing through the auxiliary counter electrode. As the material of the auxiliary counter electrode 8, it is preferable to use platinum, which is resistant to deterioration. 4 was provided as the electrolytic solution supply port of the present invention. Further, the electrolytic treatment liquid 5 enters the electrolytic solution supply port 4, passes through the distributor 12, enters the cavity 13 so as to be uniformly distributed in the entire width direction of the radial drum roller 2, and the slit 1
4 is ejected into the electrolyte passage 15. In FIG. 1, the edge liquid supply nozzles 16a and 16b are connected to the main counter electrodes 3a and 3 respectively.
Although it is provided for each b, the number of edge liquid supply nozzles may be two or more, and the position and structure of the edge liquid supply nozzles are not limited to the round tube, and may be square or elongated. However, the center position of the edge liquid supply nozzle is preferably 50 mm inside from both edges of the metal web. The point is to prevent the electrolytically treated liquid solution from flowing from the central portion to both edge portions by providing the edge liquid supply nozzle. these,
By providing a plurality of edge liquid supply nozzles at two or more locations to form a curtain film and filling the liquid flow at both edges of the radial drum, the entire width of the processing liquid from the electrolytic solution supply port can be naturally mixed and stirred. Uniform electrolyte concentration and temperature,
It is possible to make the concentration and temperature of the electrolytic treatment liquid that comes into contact with the metal web uniform, which makes it possible to make the sand uniform and densified, increasing the electrolysis efficiency and increasing the line speed. ..

[0009]

【Example】

(Embodiment 1) Using an apparatus as shown in FIG. 1, 1500 l / min from the electrolytic solution supply port 4, edge liquid supply nozzle 16a
Alternatively, a total of 2400 l / min of the electrolytic treatment solution was supplied from 16b at 100 l / min × 9 places, and the electrolytic treatment solution was discharged from the electrolytic solution discharge port 6. The conditions at this time are: Main counter electrode: Carbon auxiliary counter electrode: Platinum web and its counter electrode clearance: 10 mm Main counter electrode electrolytic treatment liquid condition: Treatment liquid nitric acid concentration 50 g / l Temperature 60 ° C Auxiliary electrode electrolytic treatment liquid condition: Treatment liquid nitric acid The concentration was 50 g / l, the temperature was 20 ° C., the web width was 1000 mm, the processing speed was 15 m / min, and the frequency was 100 Hz. When graining was performed under the above conditions, the concentration of nitric acid at the inlet was 50 g / l
In contrast, the outlet nitric acid concentration near the metal web was 40 g / l.
The temperature in the vicinity of the metal web at the outlet was 62 ° C. while the inlet temperature was 60 ° C., and uniform and fine graining was possible, and the electrolysis efficiency was increased. The same effect was obtained in the anodizing treatment.

(Comparative Example-1) Using the apparatus shown in FIG. 3, processing was performed under the same conditions as in Example-1. At that time, the supply amount of the electrolytic treatment solution is limited to 2400 l / min, and the nitric acid concentration of 50 g / l at the inlet makes it impossible to uniformly mix the electrolytic treatment liquid.
However, the temperature was 60 ° C., but the temperature in the vicinity of the metal web at the outlet was 68 ° C. Therefore, the grain was also a non-uniform rejected product.

[0011]

As is apparent from the above embodiments, by providing the main counter electrode of the present invention with a plurality of edge feed nozzles, it is possible to bring the concentration and temperature of the electrolytic treatment solution closer to the inlet and the outlet. As a result, the uniformity and the denseness of the grain are maintained, the electrolysis efficiency is increased, and the production speed can be improved, which greatly contributes to quality improvement and product cost reduction.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of an electrolytic treatment apparatus of the present invention.

FIG. 2 is a front sectional view of the electrolytic treatment apparatus of the present invention shown in FIG.

FIG. 3 is a side sectional view of an example of a conventional electrolytic treatment apparatus.

[Explanation of symbols]

 1 Metal Web 2 Radial Drum Rollers 3a, 3b Main Counter Electrode 4 Electrolyte Supply Port 5 Electrolysis Solution 6 Electrolyte Discharge Port 7 AC Power Supply 8 Auxiliary Counter Electrode 9 Diode 10 Insulator 11 Supply Pipe 12 Distributor 13 Cavity 14 Slit 15 Electrolyte Passage 16a, 16b Edge liquid supply nozzle

Claims (1)

[Claims] 1. An electrolytic treatment apparatus for supplying an alternating waveform current between a metal web and a counter electrode in an electrolytic treatment liquid containing metal ions to continuously electrochemically treat the metal web, An electrolytic treatment apparatus characterized in that a plurality of edge liquid supply nozzles are provided to the web from both sides of the main counter electrode on both edges of the web.