JPH02240299A - Electrolytically treating device - Google Patents

Abstract

PURPOSE:To obtain an electrolytically treating device capable of making sand dressing uniform and dense and of enhancing electrolysis efficiency by supplying the electrolytic treating liquid contg. metallic ions between a metallic web and the counter electrodes and providing one or a plurality of means for agitating this electrolytic treating liquid in the passage of the electrolyte. CONSTITUTION:A metallic web 1 is traveled along a radial drum roller 2 while holding the clearances against both the main counter electrodes 3a, 3b and an auxiliary counter electrode 8 constant. Alternating wave-form current is allowed to flow between the main counter electrodes 3a, 3b and the auxiliary counter electrode 8 from an AC power source 7 and electrochemical treatment is performed for the web 1. In the meantime, jetted liquid is sent to a cavity 13 via a feed pipe 12 from a jetted liquid feeder 11 provided to the insulator 10 part of the boundary between the counter electrodes 3a, 3b and ejected into the passage 15 of electrolyte through the slits 14. The spent electrolytic treating liquid 5 near to the web 1 is agitated and mixed with the fresher treating liquid 5 in the counter electrodes 3a, 3b sides opposed thereto by this jetted liquid. Thereby the web 1 is brought into contact with fresh treating liquid 5 than in the conventional practice and quality of sand dressing is made more uniform and electrolysis efficiency is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electrolytic treatment apparatus, which is suitable for roughening a metal web using an alternating waveform current, and is particularly suitable for 1. roughening for offset printing plates. This invention relates to an apparatus for electrolytic treatment of a printing plate support made of aluminum plate.

[Conventional technology]

Aluminum plates are used as printing plate supports, especially lithographic printing plate supports. Due to the diversification of users, aluminum plates have diversified from those close to pure aluminum to those with manganese added to increase strength. ing.

In order to use such an aluminum plate as a lithographic printing plate support, it is necessary to have appropriate adhesion to the photosensitive material and water retention.

In order to do this, the surface of the aluminum plate must be roughened to have a uniform and finely grained surface. Since it has a significant effect on printing performance, its quality is an important factor in plate material production.

Methods for roughening the surface of aluminum supports for printing plates include mechanical graining, electrochemical graining, and the like, and surface roughening is carried out by appropriately combining these methods.

Mechanical graining methods include, for example, pole graining,
Wire dalein, brush grain.

There is a liquid honing method. Furthermore, as an electrochemical graining method, an alternating current electrolytic etching method is generally employed, and the current used is a normal sinusoidal alternating current or a special alternating waveform current such as a rectangular wave. Further, as a pretreatment before this electrochemical treatment, etching treatment with caustic soda or the like may be performed.

Among these, the AC electrolytic etching method has a problem in that, unlike the phenomenon caused by DC current, the counter electrode made of carbon or metal is extremely susceptible to deterioration.For example, if carbon is used as the counter electrode, an oxidation-reduction reaction occurs every time the polarity changes. This is repeated and the binder deteriorates rapidly, making stable operation over a long period of time extremely difficult.

To solve this problem, Japanese Patent Publication No. 61-48596 discloses that a circuit for an auxiliary counter electrode is connected in parallel to a circuit connected to a main counter electrode, and a diode is installed to control the flow of anode current in the main counter electrode. Alternatively, an electrolytic treatment apparatus is disclosed in which a mechanism acting like a diode is provided in a circuit for an auxiliary counter electrode. For example, as shown in FIG. 3, a metal web 1, which is a material to be treated, is supported around the circumference of a radial drum roller 2, and a main counter electrode 3a facing
. The main counter electrodes 3a, 3b are supplied with an alternating waveform current from an alternating current power source to perform electrochemical treatment. , a circuit for the auxiliary counter electrode 8 is connected in parallel to the circuit connected to the main counter electrodes 3a and 3b, and a circuit for the anode current at the main counter electrode is connected in parallel to control the flow of the anode current at the main counter electrode. This is an electrolytic treatment apparatus in which a diode 9 or a mechanism acting like a diode is provided in the circuit for the auxiliary counter electrode 8 to flow current.

In this case, the pairs 113a and 3b have opposite polarities and are connected to the AC power source 7 on opposite sides, and each pair i3a and 3b has a large number of wires (for example, n=1).
0 to 14) small electrodes (3a3at+31s・
...38a) (3b+, 3bt.

3bs...3b,) are configured with an insulator lO as a boundary, and are devised to increase current efficiency.

[Problem to be solved by the invention]

However, the electrolytic treatment liquid 5 replenished from the electrolyte supply port 4 flows to the opposite side of the radial drum roller 2 through a narrow electrolyte passage 15 between the metal web 1 and the electrodes 3a, 3b, and the electrolyte As it exits to the discharge port 6, the electrolytic treatment solution gradually becomes fatigued due to electrolysis in the flow path, and a difference in the components develops between the electrolyte supply port 4 and the electrolyte discharge port 6, causing damage to the entire electrolytic treatment apparatus. There was a problem that sufficient electrolytic efficiency could not be obtained.

In particular, in the treatment liquid on the metal web l side in the electrolyte passage 15,
Mixing with the treatment liquid on the electrodes 3a, 3b side of the electrolyte passage 15 is insufficient, resulting in a significant degree of fatigue, resulting in non-uniform graining, that is, deterioration of electrolytic quality and electrolytic efficiency.

Therefore, in order to maintain a uniform and dense grain and increase electrolysis efficiency, a method has been used to increase the flow rate supplied from the electrolyte supply port 4. However, increasing the amount of supplied liquid increases costs. Not only did it connect, but even if the flow rate was increased, a sufficient desired grain could not be obtained.

In addition, the above-mentioned problem becomes more noticeable as the entire electrolytic treatment apparatus responds to an increase in line speed, and becomes a major constraint on increasing line speed.

An object of the present invention is to solve these conventional problems and to provide an electrolytic treatment apparatus that has uniform and dense graining, has good electrolytic efficiency, and is effective in increasing line speed.

[Means and effects for solving 11B] That is, the above object of the present invention is to supply an alternating waveform current between a metal web and a counter electrode in an electrolytic treatment solution containing metal ions to continuously flow the metal web. An electrolytic treatment apparatus that performs electrochemical treatment on a metal web and a counter electrode, the electrolytic treatment apparatus comprising one or more means for stirring the electrolytic treatment liquid supplied between the metal web and the counter electrode in an electrolyte passageway. achieved by.

The stirring means for the electrolytic treatment solution in the electrolyte passage in the present invention may be a means for generating a jet stream that sprays the electrolyte treatment liquid against the metal web surface, or a means for stirring and mixing the liquid flow in the electrolyte passage. Any means may be used,
For example, a means for stirring and mixing the electrolytically treated liquid in the passage by spraying the liquid perpendicularly onto the metal web through a slit, a stirring blade having a rotating shaft spanning the width direction of the electrolyte passage, and a means for stirring and mixing the electrolytically treated liquid in the electrolyte passage. Examples include a baffle plate that directs the electrolyte toward the metal web, and a diaphragm mechanism that contracts and expands the electrolyte passage.

Embodiments 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. 1 is a metal web, and 2 is a radial drum roller that supports the web. The metal web 1 runs while maintaining a constant clearance with the main counter electrodes 3a, 3b and the auxiliary counter electrode 8. The appropriate clearance is usually about 3 to 50 mm.

The ratio of the main counter electrode to the auxiliary counter electrode varies depending on the desired electrolytic etching conditions. 7 is an AC power supply, usually 0.1 to 500
A Hz AC power source is used. The frequency is changed depending on the desired etching form, but the frequency is 15H.
If it is less than z, the main counter electrodes 3a and 3b will deteriorate significantly, especially in the case of carbon.

There are various waveforms, but the
It is also possible to use the special alternating waveforms described in each publication. 9 is a diode;
This controls the current flowing to the auxiliary counter electrode of B. As the material for the auxiliary counter electrode 8, it is preferable to use platinum, which is resistant to deterioration.

In FIG. 1, as an electrolytically treated solution stirring means in the present invention,
A jet liquid supply device 11 is provided at the insulator section at the boundary between the main counter electrode 3a and the 1i3b.

In the jet liquid supply device 11 , the jet liquid enters the cavity 13 through the supply pipe 12 and is ejected from the slit 14 into the electrolyte passage 15 .

Due to this jet liquid, the exhausted electrolytic treatment liquid near the metal web 1 is mixed at* with the fresher electrolytic treatment liquid on the opposite main pair i3a, 3b side, and thus the metal web 1 is Since contact is made with a fresher electrolytic solution than in the past, the quality of the graining becomes more uniform and the electrolytic efficiency increases.

In this type of electrolytic processing apparatus in which the metal web 1 is supported by the radial drum roller 2, the electrolytic processing liquid 5 flowing through the electrolytic liquid passage 15 forms a film on the surface of the metal web 1, forming a film on the main counter electrodes 3a, 3b side. This is thought to be because it becomes difficult to mix with the electrolytically treated solution flowing through the water. Therefore, it is considered that the stirring means in the electrolytic solution passage plays a very effective role in equalizing the processing solution and renewing the film on the surface of the metal web.

The jet liquid supplied from the jet liquid supply device preferably has the same composition, concentration, and temperature as the electrolytic treatment liquid, but other components may be at a temperature of 5 degrees Celsius per meter as long as it does not adversely affect the electrolytic treatment liquid. do not have.

Furthermore, since the main effect of the jet liquid is to produce a stirring action, it is desirable that the jet liquid be supplied at a speed that provides a large stirring effect even if the amount of the jet liquid is small.

Further, in order to enhance the stirring effect, the jet liquid supply device 11 is configured such that, for example, the metal web l is
It is also effective to provide one or more slits 14 that allow the jet to flow at right angles to the air. By this jet flow, the fatigued electrolytic treatment liquid on the surface of the metal web is removed and the electrolyte passage 15
The entire flow rate of the electrolytically treated liquid 5 in the chamber becomes uniform in concentration and temperature,
The metal web 1 comes into contact with a fresher electrolytic treatment solution, and is evenly and densely grained, increasing the electrolytic efficiency.

In the present invention, as a means for stirring the electrolytically treated liquid supplied between the metal web 1 and the main counter electrode 3a3b, a method using a liquid jet is shown in FIG. Any means can be used as long as it can stir the electrolyte treatment solution in the passage (for example, one example is a means that rotates across the width of the electrolyte passage shown in Fig. 1 and Fig. 2 (a)). It is also effective to arrange stirring blades 16 having shafts at necessary locations.

Further, the number of stirring means may be any number as long as it is one or more, and the positions thereof can be determined freely.

In addition, as shown in FIG. 2 0)) and (C), the flow of the electrolytic treatment solution contracts and expands at the insulator 10 at the boundary between the main counter electrode 3a and the main counter electrode 3b. A tubular member 17, a baffle plate 18, etc. may be provided.

(Example) Example-1 Using the apparatus shown in Fig. 1, 25,004 liters of electrolytically treated solution was supplied from the electrolyte supply port 4. /sin is supplied, and the same liquid as the electrolytic treatment liquid of the main counter electrode shown below is supplied from the jet liquid supply device 11 to 1001.
Jet stirring was performed at a flow rate of /win.

The conditions at this time are 1:8i = Carbon auxiliary counter electrode: Clearance between the platinum web and its counter electrode: 1O. Electrolytic treatment solution conditions for the main counter electrode: Treatment solution Nitric acid concentration 50g/j! Temperature: 60℃ Kamisuke counter electrode electrolytic treatment solution conditions: Treatment solution nitric acid concentration: 50
g/1 Temperature 20°C Web width 1000 sheets Processing speed
15 ugliness/sin frequency
It was 10011z.

When graining was carried out under the above conditions, uniform and dense grains could be produced.

Comparative Example-1 Using the apparatus shown in Figure 3, the amount of electrolytic treatment solution supplied was 25 Q.
01/sin, and graining was performed under the same electrolytic treatment liquid conditions as in Example-1, but the electrolytic treatment liquid in contact with the metal web and the electrolytic treatment liquid flowing on the main opposite electrode side could not mix. , fatigue of the electrolytic treatment solution in contact with the metal web was directly manifested, resulting in uneven grains on the metal web.

〔Effect of the invention〕

As is clear from the above embodiments, in the electrolytic treatment apparatus of the present invention, the concentration of the electrolytic treatment liquid in contact with the metal web is increased by means of stirring the electrolytic treatment liquid supplied between the metal web and the counter electrode, and as a result, sand The uniformity and fineness of the eyes are maintained,
The electrolysis efficiency has increased, making it possible to speed up the production line, greatly contributing to improving quality and reducing product costs.

[Brief explanation of drawings]

FIG. 1 is a side view of one embodiment of the electrolytic treatment device of the present invention, and FIGS. 2(a), (b), and (C) are partial side views of another embodiment of the electrolytic solution stirring device of the present invention. FIG. 3 is a side view of an example of a conventional electrolytic treatment apparatus. l... Metal web 2... Radial drum rollers 3a, 3b... Main counter electrode 4... Electrolyte supply port 5... Electrolytic treatment liquid 6... Electrolyte discharge lower... AC power supply 8 ...Auxiliary counter electrode 9...Diode 10
... Insulator 11 ... Jet liquid supply device 12 ... Supply pipe 13 ... Cavity 14 ...
Slit 15... Electrolyte passage 16... Stirring blade 17... Pentier tubular object 18...

Claims (1)

[Claims] In an electrolytic treatment apparatus that continuously applies an electrochemical treatment to the metal web by supplying an alternating waveform current between the metal web and the counter electrode in an electrolytic treatment solution containing metal ions, between the metal web and the counter electrode. An electrolytic treatment device characterized by having one or more means for stirring the electrolytic treatment solution supplied to the electrolytic treatment solution in an electrolytic solution passage.