JPH0215198A - Electrolytic device - Google Patents

Abstract

PURPOSE:To improve the uniformity in the electrolyte concn. and agitating effect and to increase the electrolysis efficiency by applying an AC current between the material to be treated and counter electrode in the electrolyte, and supplying the electrolyte from plural electrolyte supply ports between the counter electrodes. CONSTITUTION:A metallic web 1 is supported by the periphery of a drum roller 2 and traveled, and main counter electrodes 3a and 3b and an auxiliary counter electrode 8 provided with a diode 9 are arranged in opposition to the web 1. An AC current is applied between the web 1 and the counter electrodes 3a, 3b, and 8 from an AC power source 7, and an electrolyte 5 is supplied to an electrolytic cell 15 in between from the electrolyte supply port 4a. Consequently, the surface of the web 1 is electrochemically treated. In this electrolytic device, the electrolyte supply ports 4b-4d are further provided at >=2 positions between the main counter electrodes 3a and 3b. By this method, the concn. of the electrolyte in the cell 15 is uniformized, the electrolyte is sufficiently agitated, an electrolysis efficiency is improved, and the surface of the web 1 is uniformly electrolyzed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrolyte replenishment port in an electrolytic processing apparatus, and is suitable for roughening the surface of a metal web by alternating current, and is particularly suitable for use in offset printing plates. The present invention relates to an electrolytic treatment apparatus for a printing plate support made of a roughened aluminum plate suitable for use in the present invention.

[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.

For this purpose, the surface of the aluminum plate must be roughened to have uniform and dense grains. This surface roughening treatment has a significant effect on the printing performance such as staining performance of the plate material when printing is actually performed, so its quality is an important factor in the production of the plate material.

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.

Examples of mechanical graining methods include ball grain,
There are wire grain black grain liquid honing methods. Furthermore, as the electrochemical graining method, an alternating current electrolytic etching method is generally employed, and the current used is a special alternating current such as an ordinary sine wave alternating current or a rectangular wave. Further, as a pretreatment of this electrochemical grained cloth, etching treatment with caustic soda or the like may be performed.

Among these, the alternating current electrolytic etching method has a problem in that, unlike the phenomenon caused by direct current, the counter electrode made of carbon, metal, etc. is extremely susceptible to deterioration. For example, if carbon is used as a counter electrode, redox reactions are repeated every time the polarity changes, causing severe deterioration of the binder and making stable operation over a long period of time extremely difficult.

In order to solve such problems, Japanese Patent Publication No. 61-48596 discloses a method in which a circuit for an auxiliary counter electrode is connected in parallel to a circuit connected to a main counter electrode, and the flow of anode current to the main counter electrode is controlled. An electrolytic treatment apparatus is disclosed in which a diode or a mechanism acting like a diode is provided in a circuit for an auxiliary counter electrode. For example, as shown in FIG. 2, a metal web 1, which is a material to be treated, is supported around the circumference of a drum roller 2, and an electrolytic treatment solution containing metal ions is supplied between an electrolyte supply 114 and opposing main counter electrodes 3a and 3b. The main counter electrodes 3a and 3b are supplied with alternating current from the main counter electrodes 3a and 3b. A counter electrode to the web 1 is formed by the main counter electrodes 3a, 3b and the auxiliary counter electrode 8, and a circuit for the auxiliary counter electrode 8 is connected in parallel to the circuit connected to the main counter electrodes 3a, 3b.
- An electrolytic treatment device in which the circuits for the main counter electrode of the current are connected in parallel, and a diode 9 for controlling the flow of the anode current at the main counter electrode or a mechanism acting like a diode is provided in the circuit for the auxiliary counter electrode 8 to flow the current. be.

At this time, the main counter electrodes 3a and 3b have opposite polarities and are connected to the power source 7 on opposite sides, and each of the main counter electrodes 3a and 3b has a large number of wires (for example, n-10 to 14
small electrode (3a1.3az3a3 H+ ・3an
, ) (3b+, 3bz, 3b:+ ...3 bn)
are constructed with an insulator 10 as their boundary, and are devised to increase current efficiency.

[Problem to be solved by the invention]

However, in the past, there was only one electrolyte supply port 4! The electrolyte supplied from the metal web 1 and the electrodes 3a, 3
a narrow space (e.g. 10 mm) between
through the electrolyte outlet 6 to the opposite side of the drum roller 2
Therefore, the electrolyte is gradually fatigued by the electrolysis that flows into the flow path, and the electrolyte is fatigued at the beginning and end of the main counter electrode, resulting in a difference in its components, making it impossible to obtain sufficient electrolytic efficiency.

Furthermore, the temperature difference between the inlet and outlet of the liquid became large, making it impossible to obtain the desired grain.

SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problems and provide an electrolytic treatment apparatus with high electrolytic efficiency.

[Means and effects for solving the problem] That is, the above object of the present invention is to perform electrochemical treatment by supplying an alternating current between a material to be treated and a counter electrode in an electrolytic treatment solution containing metal ions. This is achieved by an electrolytic treatment method characterized in that the electrolytic treatment apparatus is provided with electrolyte supply ports at two locations between the counter electrodes.

In the present invention, the electrolyte supply port in Q is placed at two or more locations between the counter electrodes.
The provision of this means that electrolyte supply ports are provided at two or more necessary locations to prevent electrolysis efficiency from decreasing due to fatigue of the electrolyte in the electrolyte passage.

Further, as the electrolyte supply port, a slit liquid supply nozzle is preferable.

Embodiments will be described below using figures. FIG. 1 shows one embodiment of the electrolytic treatment method of the present invention. 1 is a metal web, and 2 is a radial tram roller supporting the web, which runs while maintaining constant clearances between the web and the main counter electrodes 3a, 3b and the auxiliary counter electrode 8. Clearance is usually
Approximately 3 to 50 mm is appropriate. 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. An AC power source of IHz to 500 Hz is used. The frequency is changed depending on the desired etching form, but the deterioration of the main opposite electrodes of 3a and 3b is 1
If it is 5 Hz or less, it is large, especially in the case of carbon. There are various waveforms, but the
It is also possible to use the special alternating waveforms described in Japanese Patent Publication No. 9280 and Japanese Patent Publication No. 55-191.91. A diode 9 controls the current flowing to the auxiliary counter electrode 8.

As the material for the auxiliary counter electrode 8, it is preferable to use platinum, which is resistant to deterioration.

As the electrolyte supply port 4 of the present invention, for example, if the conventional one is 4a, an insulator 10 is sandwiched between the small electrode in the middle of the main counter electrode 3a, and the electrolyte supply port 4b is connected to the main counter electrode 3a and the main counter electrode 3a.
An insulator 10 is also inserted between the main counter electrode 3b and an electrolyte supply port 4c, and an electrolyte supply port 4d is provided in the same manner as described above in the middle of the main counter electrode 3b.

At each electrolyte supply port, the electrolytic treatment solution 5 enters the electrolyte supply port 4 through the supply pipe 1, enters the cavity 13 by the distributor 12 so as to be uniformly distributed over the entire width direction of the drum roller, and enters the cavity 13 through the slit 14. It is ejected into the electrolytic cell 15. This allows the electrolyte concentration in the electrolytic cell to become even.
This improves the electrolytic efficiency and stirring effect, leading to an increase in electrolytic efficiency.

〔Example〕

Example-1 Using the device shown in Figure 1, the electrolyte supply ports 4a, 4
A total of 4000 p/min of electrolyte solution was supplied from b, 4C, and 4d.

Main counter electrode: Carbon Auxiliary counter electrode: Clearance between the counter electrode and the platinum web ゛10mm Main counter electrode electrolyte conditions: Liquid type Nitric acid concentration 50g//! Temperature: 60°C Electrolyte conditions for auxiliary counter electrode: Liquid type: Nitric acid concentration: 50
g/ffi Temperature 20'C Aluminum web width ], 000 mm Processing speed
When graining was carried out at a speed of 15m/min and a frequency of 100Hz or higher, the inlet concentration was 50%.
The g/C outlet concentration was 48 g#2, and grains were uniform.

Comparative Example Comparison was carried out using the apparatus shown in Fig. 2 under the same conditions as in the example, and the electrolyte supply was limited to 2500 ρ/min, the outlet concentration was reduced to 40 g/E, and the grain was non-uniform.

〔Effect of the invention〕

As is clear from the above examples, by providing the required number of electrolyte supply ports for the main counter electrode of the present invention at two or more locations between the material to be treated and the counter electrode, the electrolytic efficiency is increased, the production speed is increased, and the metal The uniformity of the sand H in the width direction of the web was further improved, contributing to improved quality.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the electrolytic treatment apparatus of the present invention, and FIG. 2 is a side view of an example of a conventional electrolytic treatment apparatus. 1... Metal web 2... Radial 1' ram roller 3a, 3b... Main counter electrode 4a 4b, 4c... Electrolyte supply port 5... Electrolyte treatment solution 6... Electrolyte discharge port 7. ... AC power supply 8 ... Auxiliary counter electrode 9 ... 10 ... Insulator 11 12 ... Dis 1-rebuter 13 ... Cavity 14° - Diode ... Supply tube ... Slit

Claims (1)

[Claims] An electrolytic treatment apparatus that performs electrochemical treatment by supplying an alternating current between a material to be treated and a counter electrode in an electrolytic treatment solution containing metal ions, the electrolytic solution supply ports being provided at two or more locations between the counter electrodes. An electrolytic treatment device characterized by being provided in.