JPH05125597A - Anodic oxidation device andan0dic oxidation method for planographic printing base - Google Patents

Abstract

PURPOSE:To speed up an anodic oxidation line and to increase the electrolysis quantity thereof without generating a spark accident, flawing accident, etc., in a band-shaped material to be anodized in the anodic oxidation of the planographic printing base. CONSTITUTION:An electrode 22 having an arc-shaped section is provided in an anodic oxidation cell 21 and an electrolyte 24 is packed therein. A supporting roller 25 is provided above the electrode 22. Power feed cells 26, 27 are provided on the upstream and downstream side of the anodic oxidation cell 21. Power feed liquids 28, 29 are packed in the power feed cells 26, 27 and power feed electrodes 30, 31 are provided therein. The device is so constituted that the band-shaped material 34 travels between the respective electrodes 30 and 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a support for a lithographic printing plate, and in particular, a lithographic plate made of aluminum or its alloy which has been roughened by a mechanical, chemical or electrochemical method. The present invention relates to an apparatus and method for anodizing a printing plate support.

[0002]

2. Description of the Related Art Generally, an aluminum support used for a lithographic printing plate is required to have excellent hydrophilicity and water retention property, and therefore, the surface of the aluminum support is mechanically, chemically or electrochemically processed. The surface is roughened by forming fine irregularities. Further, in order to improve the mechanical strength and the water retention property of the roughened surface, the surface is generally anodized.

Conventionally, the anodic oxidation treatment of a lithographic printing plate support has been carried out by JP-A-48-26638, JP-B-58-24517 and JP-A-47.
No. 18739, the anodizing method disclosed in each of the publications is used, and this method is called a so-called submerged power supply method. As an anodizing apparatus using this submerged power supply method, for example, there is an apparatus shown in FIG. The anodizing apparatus shown in FIG. 2 includes a power feeding unit 2 for negatively charging the aluminum product 1, an anodizing unit 3 for anodizing the negatively charged aluminum product 1, a power feeding unit 2 and an anode. It is composed of three parts of an intermediate part 4 for preventing a short circuit of a current in the liquid intermediate with the oxidation treatment part 3. Then, in the power feeding unit 2 and the anodizing unit 3, the power feeding electrode 5 and the electrolytic electrode 6 are respectively disposed in the electrolytic solution,
The power feeding electrode 5 and the electrolytic electrode 6 are connected via a DC power supply 7.

In such an anodizing apparatus,
A current from the DC power source 7 flows from the power feeding electrode 5 from the power feeding electrode 5 to the aluminum product 1 through the electrolytic solution, and the current flows in the aluminum product 1 to the anodizing treatment unit 3. As a result, an anodized film is formed on the surface of the aluminum product 1 in the anodized portion.

[0005]

However, in the above-described conventional anodizing method, the voltage loss generated in the electrolytic solution is so large that it cannot be ignored. That is,
If the distance between the aluminum product and the electrode is short in the power supply part and the anodizing part, the aluminum product may flutter or the aluminum product may come into contact with the electrode due to unstable transport, resulting in damage such as scratches or sparks and quality defects. is there. Therefore, in order to prevent these quality failures, it is necessary to increase the distance between the aluminum product and the electrode, and it is usually necessary to maintain a distance of 50 mm or more. As a result, a large voltage loss occurs in the electrolytic solution.

Further, in the conventional method, since both sides of the aluminum product are immersed in the electrolytic solution, the electric current also circulates to the opposite side surface not subjected to the anodizing treatment to form an oxide film. Therefore, in the case of producing a single-sided processed product, means for preventing the electric current from flowing into the opposite surface of the aluminum product, for example, a special means as disclosed in JP-A-57-47894. Had to be provided.

The present applicant has already proposed in Japanese Patent Application No. 3-150083 an anodizing device for solving the above problems. This lithographic printing plate support anodizing apparatus, as shown in FIG. 3, includes a support roller 15 for closely supporting a long strip 18 made of aluminum or its alloy, and the support roller 15.
Feed rollers 19 and 20 that come into contact with the strips provided upstream and downstream of 15, a substantially concentric electrode 12 installed along the outer peripheral surface of the support roller 15, the electrode 12 and the support roller
15 and an electrolyte solution 14 filled between them.

However, in this apparatus, the power feeding roller directly contacts the strip. Since the band-shaped material is roughened in the step before the anodizing treatment, minute irregularities are present on the surface. Therefore, when power is supplied by directly contacting the power supply roller with the belt-shaped material, the contact between the belt-shaped material and the power-supply roller becomes uneven, current concentrates on the contact part, and quality failure such as spark failure occurs on the surface of the belt-shaped material. In some cases,
This quality failure is particularly likely to occur when the current value is increased for high speed and high efficiency processing.

As described above, in the method in which the power feeding roller is brought into direct contact with the belt-like material, serious quality failure is likely to occur on the surface of the product, and particularly at high speed and high coating amount treatment, the occurrence frequency is very high. There was a problem that

The present invention solves the above problems, does not cause a spark failure or the like caused by the direct contact of the feeding roller with the belt-like material, and is capable of high-speed and high-coating amount support. It is an object of the present invention to provide an anodizing apparatus and method.

[0011]

The present invention has been made to achieve the above object, and an anodizing apparatus for a support for a lithographic printing plate according to the present invention is a strip made of long aluminum or its alloy. A supporting roller for closely supporting an object, an electrode on a substantially concentric circle installed along the outer peripheral surface of the supporting roller, an electrolytic solution filled between the electrode and the supporting roller, and an upstream side of the supporting roller. And a power supply tank provided on at least one of the downstream side, a power supply liquid filled in the power supply tank, and a power supply electrode provided on at least one surface side of the traveling path of the strip in the power supply liquid. It is characterized by having.

The method for anodizing a support for a lithographic printing plate according to the present invention is such that a long strip of aluminum or its alloy is conveyed in close contact with a supporting roller while being immersed in an electrolytic solution, and At least one of the upstream side and the downstream side runs in the power feeding liquid filled in the power feeding tank, and is arranged in the power feeding liquid in the power feeding tank and the substantially concentric electrodes installed along the outer peripheral surface of the support roller. The strip-shaped material is anodized by energizing the supplied power supply electrode.

The power supply tank is provided on at least one of the upstream side and the downstream side of the support roller, and is for supplying a current from a power source to the strip by the power supply electrode and the electrolytic solution in the power supply tank. Since this power supply tank can solve the problems that existed in the past, it is preferable to provide the power supply tanks on the upstream and downstream sides of the support roller, respectively.

That is, the conventional anodic oxidation treatment has the following problems. First, it was not possible to inexpensively increase the speed of the anodizing treatment line and increase the amount of anodized film.
That is, the current amount must be increased when increasing the speed of the anodizing treatment line to improve productivity and when increasing the amount of anodized film to improve quality performance. Raising the value increases the voltage drop due to ohmic loss in the aluminum product. Therefore, it becomes necessary to increase the electrolytic voltage of the power supply.

As described above, when the electrolysis voltage is increased, the amount of electric power supplied is increased, so that the running cost is increased and the power supply capacity is required to be increased, so that the facility cost is also increased. Further, since the electrolysis voltage increases, the amount of Joule heat generated in the aluminum product between the power supply electrode and the electrolysis electrode also increases, so the cooling cost for cooling the aluminum product and the electrolytic solution to a steady specified temperature is also increased. Will increase. As described above, when attempting to speed up the electrolytic treatment line with the conventional device,
It was extremely expensive.

Secondly, for thin aluminum products, it has been difficult to speed up the anodizing process line. That is,
In the intermediate part between the power supply part and the anodizing part, the total current supplied flows to the aluminum product.Therefore, when the supply current amount is large, the supply current amount is limited for thin aluminum products, It was difficult to increase the speed of the anodizing line and increase the amount of anodized film.

Therefore, if power feed tanks are provided on both sides of the support roller, current is supplied to the strip by two routes, a portion passing through the upstream power feed electrode and a portion passing through the downstream power feed electrode. , It is better with half the amount of current compared to the conventional one.

Therefore, when the speed of the line is increased, the amount of power supplied is small and the amount of heat generated during the process is reduced, so that the cooling load is reduced and the cost required for the process is drastically reduced. Moreover, since it is not necessary to use a power supply having a large boosting capability, it is possible to provide a power supply that is compact and requires less equipment cost. Further, even in the case of a thin aluminum product, the aluminum product does not melt and stable anodic oxidation treatment can be performed.

The power supply electrodes provided in the power supply tank may be provided on at least one surface side of the strip, but are preferably provided on both sides in order to make the equipment compact. Moreover, it is preferable that the gap between the strip and the feeding electrode is in the range of 2 to 100 mm. As the power feeding electrode, a lead electrode, a zinc dioxide electrode, a ferrite electrode, a platinum electrode, a platinum-plated titanium electrode, a platinum clad titanium electrode, or the like can be used.

The power supply liquid is of the type, concentration, and
The temperature and the like may be the same, but may be different.

The electrode provided along the outer peripheral surface of the support roller is preferably provided concentrically with the support roller, and the gap between the support roller and the electrode is preferably in the range of 1 to 40 mm.

The belt-like material is formed of pure aluminum or an aluminum alloy, and examples of the aluminum alloy include aluminum alloys with metals such as silicon, iron, copper, manganese, magnesium, chromium, zinc, bismuth and nickel. is there. The thickness of the band is generally 0.1-0.5 mm
The range is.

The electrolytic solution may be, for example, an aqueous solution of sulfuric acid, phosphoric acid, oxalic acid or a salt thereof, or a mixed solution thereof, and an optimum one may be selected to obtain a desired quality. The concentration and temperature of the electrolytic solution can be freely selected. The liquid filled in the power feeding electrode tank is the above-mentioned electrolytic solution and its type, concentration,
The temperature and the like may be the same or different. It is preferable that the electrolytic solution is in a flow state by an appropriate means.

As the power source waveform, a direct current is generally used, but in addition, an AC waveform, an AC / DC superposed waveform or the like can be selected as an optimum waveform to obtain a desired quality.

The current density during anodic oxidation can be freely selected. For example, it may be a constant value during the processing time, or the current density may be gradually increased.

Before the anodizing treatment of the present invention,
Usually, a roughening treatment is applied. This roughening process
A mechanical roughening method, a chemical roughening method, an electrochemical roughening method, or those for improving the water retention of an aluminum support and the adhesion to a light-sensitive material coated thereon. Is performed by a combination method.

As the mechanical surface roughening method, there are a wire brushing lining method, a brush graining method, a sandblast method, a ball graining method and the like. Examples of the chemical surface roughening method include a method of selectively dissolving the surface. As an electrochemical graining method, there is a method using nitric acid, hydrochloric acid and a mixed solution thereof as an electrolytic solution. Further, salts such as aluminum nitrate, aluminum chloride, ammonium nitrate, ammonium chloride, manganese nitrate, manganese chloride, iron nitrate and iron chloride may be added to these. Further, a neutral salt aqueous solution such as sodium chloride or sodium nitrate is also used.

Further, after the surface roughening treatment and before the anodizing treatment, if necessary, an alkali etching treatment, a neutralization treatment,
Desmutting treatment or the like can be appropriately selected and combined.

It is also possible to connect two or more units in the longitudinal direction with the above apparatus as one unit and repeat the same anodizing treatment as described above a plurality of times.

After anodizing the strip, if necessary, a sealing treatment described in JP-A-1-150583, JP-A-60-14
Hydrophilization treatment described in 9491, treatment with aqueous solution of alkali metal silicate described in U.S. Pat. No. 3,181,461, U.S. patent
The undercoat layer coating of hydrophilic cellulose containing a water-soluble metal salt described in Japanese Patent No. 3860426 can be appropriately selected and carried out.

The lithographic printing plate support according to the present invention can be used as a photosensitive lithographic printing plate by providing a photosensitive layer on the surface thereof. Examples of the composition of the photosensitive layer include a composition made of a diazo resin, a composition made of an O-quinonediazo compound, a photopolymerizable composition, a composition made of a photosensitive resin having an unsaturated double bond in the molecule, and the like.

[0032]

In the present invention, the feeding liquid acts as an intermediary between the strip and the feeding electrode, and the strip is energized in a non-contact state with the feeding electrode.

[0033]

EXAMPLE An example of an anodizing apparatus for a lithographic printing plate support of the present invention will be described with reference to FIG.

FIG. 1 is a schematic sectional view of an anodizing device for a lithographic printing plate support. In this figure, reference numeral 21 is an anodizing tank, and an electrode 22 having an arcuate cross section is provided in the anodizing tank 21. An electrolytic solution inlet 23 is provided above one end of the electrode 22.
24 is filled in the anodizing tank 21. Above the electrode 22, a support roller 25 having a concentric circumferential surface is rotatably arranged at a slight distance in a state where the lower half of the electrode is immersed in the electrolytic solution 24.

Power supply tanks 26 and 27 are provided on the upstream side and the downstream side of the support roller 21, and the power supply tanks 26 and 27 are filled with power supply liquids 28 and 29 and the power supply electrodes 30 and 31 are slightly provided. It is provided in two steps, upper and lower, with a gap between them. Conveying rollers 32 and 33 are arranged on both sides of the power feeding electrodes 30 and 31, respectively.

Aluminum product 34 as a band
Is wound around the support roller 21, and the power supply liquid 2 is provided on both sides of the support roller 21 via the transport rollers 32 and 33.
The electrodes 8 and 29 are located between the power supply electrodes 30, 30 and 31, 31.

A method for anodizing an aluminum product with the above anodizing apparatus will be described.

First, the aluminum product 34 is placed between the power supply rollers 30, 30 and 31, 31 with the surface of the aluminum product 34 to be anodized facing downward, and is brought into close contact with the support roller 21. Then, the support roller 21 is rotated to convey the aluminum product 34, and the power is turned on to supply the electric current. This supplied current is fed from the feeding electrodes 30 and 31 to the feeding liquid.
28, 29 to the aluminum product 34, further to the lowermost end in the figure inside the aluminum product 34, and then to the electrode 22 via the electrolytic solution 24, at which time the exposed surface of the aluminum product 34 is anodized. A film is formed.

Next, the results of experiments comparing the anodizing method of the present invention with the conventional anodizing method will be described.

Strips to be anodized; long JIS 1050
The aluminum strip-shaped product (thickness 0.15 mm, width 1000 mm) was subjected to the following treatment at a line transfer speed of 60 m / min. First,
The surface was grained with a rotating nylon brush using the pumice-water suspension as an abrasive. At this time, the surface roughness (center line average roughness) was 0.5 μm. After washing with water, etching was performed in a 10% caustic soda aqueous solution at 70 ° C. so that the amount of aluminum dissolved was 6 g / m ² . After the aqueous solution, it was neutralized in a 30% aqueous solution of nitric acid and washed again with water. Then, in a 0.7% nitric acid aqueous solution, a rectangular wave alternating waveform having a voltage of 13 V at the anode and a voltage of 6 V at the cathode was used (power supply waveform described in the embodiment of JP-A-52-77702) for 20 seconds for electrolytic surface roughening. The surface was washed in a 20% aqueous solution of sulfuric acid, and then washed with water.

Example 1 The above aluminum product was anodized by using the anodizing apparatus shown in FIG. 1 with a 20% sulfuric acid aqueous solution as an electrolytic solution and a power supply, a line transfer speed of 50 m / min, and an electrolytic voltage of 30V.

As a result, an oxide film having a film thickness of 1.5 μm was well formed, and the surface temperature of the aluminum product at the exit of the supporting roller was 50 ° C., so that the anodizing treatment was stably performed even after a long time. Was broken. No spark failure occurred on the surface of the aluminum product.

Example 2 Anodizing treatment was performed under the same conditions as in Example 1 except that the line transport speed was 100 m / min, but the same results as in Example 1 were obtained.

Comparative Example 1 The above aluminum product was anodized using the anodizing apparatus shown in FIG. 2 with a 20% aqueous sulfuric acid solution as an electrolytic solution, a line transfer speed of 50 m / min, an electrolytic voltage of 120 V and a supply power of 5000 kw. ..

As a result, the surface temperature of the aluminum product in the middle part was 120 ° C., and the aluminum product was blown out in about 1 minute after the start of the treatment, and the treatment could not be continued. An oxide film was also formed on the surface of the aluminum product opposite to the surface on which the oxide film was formed.

Comparative Example 2 Using the anodizing apparatus shown in FIG. 3, the above aluminum product was anodized with a 20% aqueous sulfuric acid solution as an electrolytic solution, a line transfer speed of 50 m / min, and an electrolytic voltage of 30V.

As a result, an oxide film having a thickness of 1.5 μm was formed well, and the surface temperature of the aluminum product at the exit of the supporting roller was 50 ° C., so that the aluminum product did not melt down even after a long time. It was However, the surface of the aluminum product was frequently broken due to sparks and could not be used as a support for a lithographic printing plate.

[0048]

According to the present invention, it is possible to achieve a high speed line and a high electrolysis amount without causing a quality failure such as a spark failure or a scratch on the belt-like material.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of an embodiment of an anodizing device for a lithographic printing plate support according to the present invention.

FIG. 2 is a schematic cross-sectional view of a conventional anodizing device for a lithographic printing plate support.

FIG. 3 is a schematic sectional view of another conventional anodizing device for a lithographic printing plate support.

[Explanation of symbols]

 21 ... Anodizing tank 22 ... Electrode 24 ... Electrolyte 25 ... Support rollers 26, 27 ... Feed tank 28, 29 ... Feed solution 30, 31 ... Feed electrode 34 ... Aluminum product (belt)

Claims (2)

[Claims] 1. A support roller for closely supporting a long strip of aluminum or its alloy, a substantially concentric electrode provided along an outer peripheral surface of the support roller, and the electrode and the support roller. An electrolyte solution filled in between, a power supply tank provided on at least one of the upstream side and the downstream side of the support roller, a power supply solution filled in the power supply tank, and a band-shaped material in the power supply solution. An anodizing device for a support for a lithographic printing plate, comprising a power supply electrode provided on at least one surface side of a traveling path. 2. A long strip of aluminum or its alloy is immersed in an electrolytic solution and conveyed in close contact with a support roller, and is filled in a power supply tank on at least one of the upstream side and the downstream side of the support roller. Run in the power supply,
A planographic printing plate characterized by anodizing the strip by energizing a substantially concentric electrode installed along the outer peripheral surface of the support roller and a power supply electrode arranged in the power supply solution of the power supply tank. Method for anodizing support for printing plate