JPH07278900A - Electrolytic treatment and electrolytic treating device - Google Patents

Abstract

PURPOSE:To prevent the generation of cross stroke in an electrolytic treating method for electrochemically forming a rough surface on a material to be treated by supplying alternating current between the material to be treated and a feed electrode in an electrolyte containing a metallic ion. CONSTITUTION:The width (cm) of cross stroke is determined from the line speed (m/min) of a set aluminum web 100 and the electrolytic power source frequency (Hz) of the alternating current 60. A small sized electrode 32 is determined so that the length L from the upstream side end face of a main electrode 31 to the upstream side end face of the small sized electrode 32 is almost equal to the obtained width of cross stroke. The number (c) (the main electrode 31 is included) of electrodes from the determined small sized electrode 32 to the main electrode 31 is determined and one cycle of the alternating current is divided by the numbers (c) and an current is applied while increasing by 1/c cycle from the small sized electrode 32 placed at the uppermost stream.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic treatment method and an electrolytic treatment apparatus for electrochemically roughening the surface of an aluminum web used for a PS plate support or the like.

[0002]

2. Description of the Related Art Generally, an aluminum web is used as a PS plate support, the surface of which has good adhesion to a photosensitive layer provided thereon, and the wet water used during printing is not used. It is usually roughened for holding and the like.

Conventionally, as a method of roughening, there is a method disclosed in Japanese Patent Laid-Open No. 2-298300. In this method, when a three-phase current or an alternating current is applied to the electrodes to electrochemically roughen the electrode, the frequency of the three-phase current or the alternating current is increased to a level higher than the power supply frequency of 50 Hz. The value of the frequency is adjusted to be higher as the transport speed increases.

[0004]

However, in the method disclosed in Japanese Unexamined Patent Publication No. 2-298300 mentioned above, the power supply frequency must be adjusted in order to bring the cross stroke within a predetermined range. The change of electrolysis conditions (power supply frequency) made it impossible to form a rough surface with constant performance. That is, since the cross stroke is determined by the line speed and the power supply frequency, when the line speed is changed, the power supply frequency must be changed to obtain the same cross stroke. Therefore, at different line speeds, the power supply frequency is different, and as a result, the degree of roughening is different.

Further, in the above-mentioned conventional method, the contrast of the cross stroke is large and conspicuous.

Therefore, the inventors of the present invention have filed Japanese Patent Application No. 4-191778.
In the specification, an electrolytic treatment method was proposed in which the cross strokes are made inconspicuous by overlapping the cross strokes with each other.

This electrolytic treatment method is an extremely preferable method because a constant surface roughening condition can always be obtained and the cross stroke is inconspicuous. However, although this electrolytic treatment method overlaps the cross strokes as described above, there are cases in which the cross strokes cannot be accurately overlapped, and the cross strokes may remain.

The present invention solves the above problems and maintains that a constant roughening condition can always be obtained,
An object of the present invention is to provide an electrolytic treatment method and an apparatus therefor capable of surely eliminating cross strokes.

[0009]

Means for Solving the Problems In order to achieve the above object, the inventors of the present invention diligently studied the relationship between various electrolysis conditions and cross strokes, and determined the electrolysis current pattern of the electrolytic grain initial reaction portion where the cross stroke occurs. It was found that the cross stroke can be eliminated by controlling.

That is, the electrolytic treatment method of the present invention electrochemically treats a material to be treated by supplying an alternating current between the material to be treated and the upstream electrode and the downstream electrode in an electrolytic solution containing metal ions. In the electrolytic treatment method for treating, a plurality of small electrodes are provided on the upstream side of the upstream electrode, and the length of the traveling method of the treated material is the width of the cross stroke obtained from the line speed of the treated material and the frequency of the alternating current. They are arranged in an insulated state so that they are almost the same, and the current for the entire cycle is applied to the part of the upstream electrode other than the small electrode, and the small electrode is the small electrode located on the most downstream side from the small electrode located on the most upstream side. It is configured such that a current of a partial cycle that increases evenly as it approaches the electrode is passed.

The length of the plurality of small electrodes in the running direction of the material to be treated is set to be substantially the same as the width of the cross stroke, and this length corresponds to the insulating portion existing between the small electrodes. The length is also included. Then, the width of the cross stroke is determined by the following formula.

Cross stroke width [cm] = (line speed [m / min] × 100) / (60 × alternating current frequency)

Among the upstream electrodes, the electrode that is not the small electrode is supplied with the current of the entire cycle, and the small electrode is supplied with the current of the evenly increasing cycle. For example, when five small electrodes are provided, one cycle is divided into ⅙ and 1/6, 2/6, 3/6, 4/6 and 5 from the small electrode on the upstream side.
It is supplied every 6 cycles. Even if the widths of the cross strokes are the same, if the number of small electrodes to be set is different (that is, if the width of one small electrode is different), the partial periods to be supplied are also different. For example, if seven small electrodes are provided, 1/8, 2/8 ... 6/8 and 7/8
It will be supplied in cycles.

The electrolytic treatment apparatus of the present invention includes an electrolytic treatment tank, an electrolytic solution containing metal ions stored in the electrolytic treatment tank, an upstream electrode and a downstream electrode provided at the bottom of the electrolytic treatment tank. An alternating power source for supplying a current to the upstream electrode and the downstream electrode, the upstream electrode being a plurality of small electrodes provided on the upstream side, insulating means for insulating between the small electrodes, and a small electrode Consisting of a main electrode provided on the downstream side of
Turn on the small electrodes between the alternating power source and the small electrodes.
A switching device for turning off is provided.

The plurality of small electrodes may be provided so as to meet the width of the cross stroke each time, or a large number of small electrodes may be provided in advance and used as needed according to the width of the cross stroke. When a plurality of small electrodes are provided in advance, it is appropriate to provide the width of the maximum cross stroke, and the width of one electrode is small so that various widths of the cross stroke can be accommodated. Is preferred.

The current switching device turns on and off each switch in synchronization with the frequency of the alternating power source in accordance with a preset pattern, so that the current to the small electrodes is sequentially supplied at the same speed as the progress of the material to be processed. Is sequentially stopped, and when one cycle is completed, current supply to all small electrodes is started and this operation is repeated.

As the insulating means, an insulating resin such as vinyl chloride, bakelite or Teflon is used.

The material to be treated is appropriately determined depending on its purpose, but for example, in the case of a PS plate support, an aluminum web is used.

The electrolytic solution containing metal ions is hydrochloric acid,
There is nitric acid.

[0020]

According to the present invention, in the reaction portion in the initial stage of electrolytic graining, the small electrode does not perform electrolytic action at the same speed as that of the material to be treated, so that the cross stroke is not generated.

A specific example of the electrolytic treatment method of the support for a lithographic printing plate of the present invention will be described with reference to FIG.

FIG. 1 is a schematic sectional view of an electrolytic treatment apparatus for a lithographic printing plate support. In this figure, reference numeral 10 is an electrolytic treatment tank, in which an electrolytic solution 20 is stored, and on the bottom surface of the electrolytic treatment tank 10, there are substantially the same rectangular upstream side feeding electrode 30 and downstream side feeding electrode 40, It is provided with only its upper surface exposed. The upstream power supply electrode 30 is composed of a main electrode 31 located on the downstream side and having a long width, and a plurality of small electrodes 32 located on the upstream side of the main electrode 31 and having a short width.

As shown in FIG. 2, the small electrode 32 includes five small electrodes 32A, 32B, 32C, 32D and 32 having the same size and shape.
These small electrodes 32A to 32E are provided with insulating plates 33 having the same size and shape. And
These small electrodes 32A to 32E are current switching devices.
50 switches 50A, 50B, 50C, 50D and 50E are connected respectively. Reference numeral 60 is an AC power supply, and this AC power supply 60
One terminal of which is the main electrode 31 and the current switching device
50, and the other terminal is connected to the downstream side power supply electrode 40. The small electrode 32 has a width a = 9 [mm] and the insulating plate 33 has a width b = 1.8 [mm].

An electrolytic solution supply pipe 70 is connected to one end of the bottom surface of the electrolytic treatment tank 10, and an electrolytic solution discharge pipe 71 is connected to the other end thereof. The liquid discharge pipe 71 is connected to a stock tank (not shown) that stores the electrolytic solution 20. In addition, the pass roll 80 is the electrolyte 20
And a guide plate 90 is provided between the pass rolls 80 to form a conveyance path for the aluminum web 100 as a material to be treated.

A method for electrolytically treating an aluminum web with the above electrolytic treatment apparatus will be described.

First, the cross stroke width [cm] is obtained from the set line speed [m / min] of the aluminum web 100 and the electrolytic power supply frequency [Hz] of the AC power supply 60.
Then, the small electrode 32 whose length from the upstream end face of the main electrode 31 to the upstream end face of the small electrode 32 substantially matches the obtained cross stroke width is obtained. Next, the obtained small electrode 32
The number c of electrodes from the main electrode 31 to the main electrode 31 (including the main electrode 32) is obtained, and one cycle of the AC power supply is divided by this number c, and 1 / c cycle is given from the small electrode 32 located at the most upstream side. Apply current while increasing. That is, the 1 / c periodic current flows through the small electrode 32 located on the most upstream side, and the 2 / c period is supplied to the next small electrode 32.
A periodic current flows, a (c-1) / c periodic current flows through the last small electrode 32, and c / c = 1 periodic current flows through the main electrode 31.

For example, when the width of the cross stroke is 54 mm, since 54 ÷ (9 + 1.8) = 5 [pieces], 32A to 32E are used, and the length L ₁ of the small electrode and the insulating plate is 54 mm. It is the same as the cross stroke.

When the cross stroke width is 32.5 mm, 32.5 ÷ (9 + 1.8) ≈3.01 [pieces], so 32C, 32D and 32E are used, and the length L ₂ of the small electrode and the insulating plate is 32.4 mm. Becomes

It is to be noted that an electrolytic treatment method and an electrolytic treatment apparatus in which a small electrode is similarly provided on the upstream side of the downstream electrode and used together are also effective.

[0030]

【Example】

[Example 1] JIS1050 aluminum was electrolyzed using the apparatus shown in FIG. The electrolyte is 20g nitric acid
/ L, an aluminum ion concentration of 10 g / l, and a temperature of 55 ° C, and the solution was sent to the electrolytic treatment tank via a pump. Line speed 130 [m / min], electrolytic power supply frequency 40 [Hz]
Set to. The expected cross stroke width at this time is 5.
4 [cm], and the length of the small electrode and insulating plate L = 5.4 [c
m].

The switching pattern of the switching device was set as shown in FIG. That is, one cycle of the electrolysis current is divided into six, and the current flows through all the small electrodes 32A to 32E in the first 1/6 cycle, and the next 1/6 cycle excludes the small electrode 32A in all. Current flows through all the small electrodes 32B to 32E, the current flows through all the small electrodes 32C to 32E excluding the small electrodes 32A and 32B in the third 1 / 6th round, and the last 1 / 6th round is full. The current does not flow through all the small electrodes 32A to 32E, but the current flows through only the main electrode 31.

When the electrolytic treatment was carried out under the above conditions and the aluminum plate was visually observed after the electrolytic treatment was completed, no cross stroke was observed.

[Example 2] A line speed of 78 [m / m]
Since the cross stroke width is 3.25 [cm], only the small electrodes 32C, 32D and 32E are used and the length L of the small electrodes and the insulating plate is set to 3.24 [cm]. Also,
The switching pattern of the switching device was set as shown in FIG.

When the electrolytic treatment was carried out under the above conditions and the aluminum plate was visually observed after the electrolytic treatment was completed, no cross stroke was observed.

It has been confirmed that these examples have a more remarkable effect also in the electrolytic treatment apparatus in which the small electrode is provided in the upstream portion of the downstream electrode.

[Prior Art Example 1] A conventional electrolytic treatment apparatus having no small electrode was used. That is, in the electrolytic treatment apparatus shown in FIG. 1, the main electrode extends to the place where the small electrode exists. The other conditions were the same as in Example 1.

The electrolytic treatment was carried out under the above conditions, and the aluminum plate was visually observed after the electrolytic treatment.
The cross stroke unevenness occurred at the pitch [m], and the level was very bad.

[0038]

According to the present invention, since it is possible to form a uniform rough surface without cross strokes and there are no restrictions on processing conditions due to cross strokes, it is possible to select conditions for forming good pits. it can. Further, the present invention is not limited to the embodiment, and can be applied to various embodiments within the technical scope such as providing a small electrode on the upstream side of the downstream side electrode.

[Brief description of drawings]

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

FIG. 2 is a partially enlarged view of an example of the electrolytic treatment apparatus of the present invention.

FIG. 3 is a waveform diagram of the electrolytic current of a small electrode in one example of the electrolytic treatment method of the present invention.

FIG. 4 is a waveform diagram of the electrolytic current of a small electrode in another example of the electrolytic treatment method of the present invention.

[Explanation of symbols]

 10 ... Electrolytic treatment tank 20 ... Electrolyte 30 ... Upstream electrode 31 ... Main electrode 32 ... Small electrode 33 ... Insulation plate 40 ... Downstream electrode 50 ... Switching device 60 ... AC electrode 100 ... Aluminum web

Claims (2)

[Claims] 1. An electrolytic treatment method for electrochemically treating a material to be treated by supplying an alternating current between the material to be treated and an upstream electrode and a downstream electrode in an electrolytic solution containing metal ions. Insulate a plurality of small electrodes upstream of the side electrode so that the length of the running method of the processed material is approximately the same as the width of the cross stroke obtained from the line speed of the processed material and the frequency of the alternating current. In this state, the current of the entire cycle is applied to the part of the upstream electrode other than the small electrode, and the size of the small electrode increases evenly from the most upstream small electrode to the most downstream small electrode. An electrolytic treatment method characterized in that a partial cycle current is passed. 2. An electrolytic treatment tank, an electrolytic solution containing metal ions stored in the electrolytic treatment tank, an upstream electrode and a downstream electrode provided at the bottom of the electrolytic treatment tank, an upstream electrode and a downstream electrode. And a plurality of small electrodes provided on the upstream side, an insulating plate for insulating the small electrodes from each other, and a main electrode provided on the downstream side of the small electrodes. An electrolytic treatment apparatus comprising an electrode, and a switching device for turning on / off the small electrode is provided between the alternating power source and the small electrode.