JPH11174663A - Support for lithographic form and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the physical strength and to restrict fall of an image part, damage of a non-image part, elusion of the oxide film and residual color in the photosensitive layer by respectively setting the number of holes of an oxide film surface and the number of holes of an interface between the oxide film and aluminum at a specified number. SOLUTION: The number of holes of an oxide film surface is set at 400-700 pieces/μm<2> , and the number of holes in an interface between the oxide film and aluminum is set at 700-1500 pieces/μm<2> . As a method of forming a porous oxide film of low density of 400-700 pieces/μm<2> a processing vessel 3 for positive electrode oxidization is divided into plural parts to interrupt the electrode reaction on the way, and temperature rise is thereby prevented so as to prevent the generation of yellowing even at the relatively high voltage. The number of holes can be adjusted in response to a purpose, and liquid temperature can be adjusted per each processing vessel by dividing the vessel. A desirable number of dividing is 2-20, and for dividing, plural processing vessel 3 are arranged, and each processing vessel is desirably provided with a power source to fluctuate the dividing condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lithographic printing plate support and a method for producing a lithographic printing plate support.

[0002]

2. Description of the Related Art Conventionally, a lithographic printing plate is obtained by developing a photosensitive lithographic printing plate obtained by coating a photosensitive composition in a thin layer on an aluminum plate after image exposure. The aluminum plate is usually roughened by a mechanical surface roughening method such as a brush grain method or a ball grain method or an electrochemical method such as an electrolytic grain method or a method combining the both, and then etched by an acid or an alkali. After the anodic oxidation treatment, the lithographic printing plate support is subjected to a hydrophilization treatment, if desired, to obtain a lithographic printing plate support. A photosensitive layer is provided on this support to form a photosensitive lithographic printing plate (so-called PS plate). This PS plate is usually subjected to image exposure, development, correction, gumming and steps to form a lithographic printing plate, which is mounted on a printing machine and printed.

[0003] In the field of lithographic printing plate supports, the above-described anodic oxidation treatment has conventionally been carried out using an aqueous solution of sulfuric acid, phosphoric acid, chromic acid, oxalic acid, sulfamic acid, benzenesulfonic acid, or the like, or an aqueous solution combining two or more of these. This is performed by passing a DC or AC current through the plate. As described above, the anodic oxidation treatment is performed using various kinds of electrolytes, and among them, sulfuric acid, phosphoric acid and the like are widely used.

[0004] The lithographic printing plate is affected by the pen pressure of a ball-point pen which is drawn at the time of plate making, is scratched at the time of transporting or removing dust from the plate surface during printing, and is affected by paper dust and ink particles during printing. Wear due to the effects of contact pressure and friction on the blankets and rollers. In particular, when the pen pressure by drawing with a ballpoint pen is high, in the case of an image portion, the photosensitive layer of the portion falls off, and in the case of a non-image portion, it is scratched and ink adheres, and it is generally called dirt. The phenomenon occurs, and the quality of the printed matter deteriorates, causing inconvenience. When the surface of the support is anodized, a porous aluminum oxide (alumina) film is formed on the surface of the aluminum plate. This aluminum oxide has a hard property, is hard to be scratched, and is hard to be abraded.

It has been conventionally known that the effect of the aluminum oxide film becomes stronger as the thickness of the aluminum oxide film becomes larger. However, since the ballpoint pen ink remains without being removed, stains occur during printing, and halation in the oxide film increases during image exposure,
There is a problem that the original is not faithfully reproduced with respect to the original because the halftone dot becomes thick or thin.

On the other hand, it is conventionally known that a harder film can be obtained by reducing the number of pores even if the thickness of the porous aluminum oxide film is the same. However, in order to reduce the number of holes, it is necessary to set the voltage at the time of anodizing treatment higher. Usually, the treatment is performed by increasing the current density or decreasing the concentration of the treatment solution. Due to the effects of problems and the like, the reaction progressed locally and a problem called "burn" occurred, making it difficult to produce continuously.

Further, the anodic oxide film causes contamination (residual film) in which the photosensitive layer is irreversibly adsorbed on the non-image area after development, making it difficult to distinguish between the non-image area and the image area or to perform erasing work. When the correction is performed, the correction mark is clearly left, and when the degree of the correction becomes severe, a stain is generated. In addition, since it dissolves in a developing solution having a pH of 12.5 or more, the dissolved matter accumulates in the developing solution, and scum or the like is generated. There has been a problem that it becomes sludge and clogs the pipes or adheres to the surface of the lithographic printing plate, thereby causing stains and deteriorating image quality.

Conventionally, as a countermeasure against this, a hydrophilization treatment is performed as desired after anodization treatment is performed. The hydrophilic treatment includes the alkali metal silicate described in U.S. Pat. No. 3,181,461, and U.S. Pat. No. 1,860,4.
No. 26, hydrophilic aryl cellulose described in British Patent No. 2,098,627, polyvinyl phosphonic acid described in JP-B-46-35885, JP-B-6-94234. Amino acids and salts thereof described in JP-B-6-2436, amines having a hydroxyl group and salts thereof described in JP-B-5-32238, phosphates described in JP-A-62-19494, and salts thereof. Development using a polymer compound containing a monomer unit having a sulfo group described in JP-A-59-101651, a compound having an amino group and a phosphonic acid group described in JP-A-63-165183, a salt thereof, or the like is used. Techniques have been proposed to reduce the residual color after and to improve the hydrophilicity of the non-image area after development. However, since these hydrophilic treatments cause insufficient adhesion to the photosensitive composition and deteriorate printing durability, it is necessary to pay close attention to control of the treatment conditions.

After anodizing, hot water treatment, boiling water treatment, steam treatment, and alkali metal silicate treatment or boehmite treatment described in US Pat. No. 3,181,461 are used. There has been proposed a method of suppressing the dissolution in a developing solution by performing a treatment for generating a crystalline hydrated oxide in pores by, for example, a method described above. However, in the case of the alkali metal silicate, as described above, the adhesion to the photosensitive layer is reduced, and the boehmite treatment improves the residual color after development, but reduces the hydrophilicity and reduces stains. There was a problem that it easily occurred.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a film having excellent physical strength even when the oxide film is a thin film. An object of the present invention is to provide a lithographic printing plate support in which elution of an oxide film and residual color of a photosensitive layer are suppressed, and a method for producing the same.

[0011]

The object of the present invention is achieved by adopting the following constitution.

(1) In a roughened and anodized aluminum support, the number of pores on the surface of the oxide film is 400 to 400.
A lithographic printing plate support, wherein the number of holes is 700 / μm ² and the number of holes at the interface between the oxide film and aluminum is 700 to 1500 / μm ² .

(2) The method for producing a lithographic printing plate support as described in (1), wherein the roughened aluminum support is divided into a plurality of pieces when anodizing is performed. A method for producing a lithographic printing plate support.

(3) When the roughened aluminum support is divided into a plurality of pieces at the time of anodizing treatment, different conditions are included in each of the anodizing conditions. (2) The method for producing a lithographic printing plate support according to (2).

(4) The number of divisions of the anodic oxidation treatment is 2 to 20
The method for producing a lithographic printing plate support according to (2) or (3), wherein

(5) When the number of divisions is n, the voltage E at the time of anodic oxidation treatment is E1 ≧ E2... ≧ En, E1 is 20 to 40V, and 1 is such that En is 10 to 20V. (2), (3) or (4), wherein the anodizing treatment is performed n times in order from the above.

(6) The number of holes of the oxide film on the surface is 400 to
Was 700 / [mu] m ^2, pore number of the interface between the oxide film and the aluminum is characterized in that it is a 700 to 1500 pieces ^{/ μm 2 (2), (} 3), (4) or (5) described A method for producing a lithographic printing plate support.

(7) The lithographic printing plate as described in any one of (2) to (6) above, wherein when the anodic oxidation treatment is divided into a plurality of treatments, a hydrophilic treatment is performed during the division. A method for producing a support.

(8) The lithographic printing plate according to any one of (2) to (7), wherein, when the anodic oxidation treatment is divided into a plurality of treatments, a boehmite treatment is performed during the division. A method for producing a support.

The present inventors have conducted intensive studies focusing on the number of holes in the anodic oxide film. As a result, the number of holes on the surface of the porous oxide film was 400 to 700 / μm ² , It has been found that the above object can be attained by setting the number of pores at the interface to 700 to 1500 / μm ² .

400 to 700 porous oxide films / μm
^As a method of forming at a low density of ^2, the process of anodizing treatment is divided into a plurality and the method of interrupting the electrolytic reaction on the way suppresses temperature rise, and "burn" does not occur even at relatively high voltage I found something. In addition, by dividing the tank, the number of holes can be adjusted according to the purpose,
In addition, it has been found that the liquid temperature can be adjusted for each processing tank, so that the liquid can be stably provided.

Further, the hydrophilic treatment and the boehmite treatment are performed by
It has been found that by performing the treatment in the middle of the dividing treatment, a support excellent in stain and adhesion can be more stably provided.

The support used in the present invention includes a support made of pure aluminum and an aluminum alloy. Various aluminum alloys can be used,
For example, an alloy of aluminum with a metal such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, nickel, titanium, sodium, or iron is used.

Prior to roughening, the aluminum support is preferably subjected to a degreasing treatment to remove grease, rust, dust and the like on the aluminum surface. As the degreasing treatment, solvent degreasing using a solvent such as trichlene or thinner, emulsion degreasing treatment using an emulsion of kerosene, triethanolamine or the like is used. Also, in order to remove dirt and natural oxide film that cannot be removed only by the above degreasing treatment,
An aqueous alkaline solution such as caustic soda can also be used.

When an alkaline aqueous solution such as caustic soda is used for the degreasing treatment, smut is formed on the surface of the support. In this case, an acid such as phosphoric acid, nitric acid, sulfuric acid, chromic acid, etc.
Alternatively, it is preferable to perform a desmut treatment by immersing in a mixed acid thereof.

The surface roughening method includes a method of mechanically roughening the surface, a method of electrochemically roughening the surface, and a method of roughening the surface with an etching agent comprising an alkali, an acid, or a mixture thereof. There is a target surface roughening method. Also, a method combining these can be used.

The mechanical surface roughening method includes, for example, ball polishing,
There are methods such as brush polishing, blast polishing, buff polishing, and honing polishing. Among them, brush polishing and honing polishing are preferable. Further, the sheet can be roughened by pasting a previously roughened sheet to the surface of the support and applying a pressure to transfer the rough surface pattern.

As the electrochemical surface roughening method, there is a method in which the surface is electrolytically treated by alternating current or direct current in an acidic electrolytic solution containing, for example, hydrochloric acid or nitric acid.

The electrolytic surface roughening treatment is described, for example, in JP-B-48-28123 and British Patent 896,563.
And in the specification of Japanese Patent Application Laid-Open No. 53-67507, these methods can be used in the present invention.

The voltage applied in the electrochemical graining is preferably 1 to 50 V, more preferably 2 to 30 V. Further, an alternating waveform current such that the quantity of electricity at the anode (hereinafter referred to as Qa) becomes larger than the quantity of electricity at the cathode (hereinafter referred to as Qc) is added, and the current density at the anode is 10 to 150 A /
It is good to perform electrolytic surface roughening under the condition of dm ² , preferably 20 to 100 A / dm ² .

The alternating waveform current used in the present invention is a waveform obtained by alternately switching the positive and negative polarities.
Any waveform can be used as long as Qa is larger than c.

Qa and Qc are preferably from 100 to 1000 Coulomb / dm ² . The temperature is preferably from 10 to 50C, more preferably from 15 to 45C. The concentration of hydrochloric acid or nitric acid is preferably 0.01 to 15% by weight.

If necessary, nitrates, chlorides, amines, aldehydes, phosphoric acid, chromic acid, boric acid, acetic acid, oxalic acid and the like can be added to the electrolytic solution.

In the case where the surface is electrochemically roughened after the surface is mechanically roughened, it is preferable to perform a chemical etching process of dipping in an aqueous solution of acid or alkali between each process. Examples of the acid include sulfuric acid, persulfuric acid, hydrofluoric acid, phosphoric acid,
Examples include nitric acid and hydrochloric acid, and examples of the base include sodium hydroxide and potassium hydroxide. Among these, it is preferable to use an aqueous alkali solution. A treatment is carried out at a solution temperature of 40 to 100 ° C. for 5 to 300 seconds using a 0.05 to 40% by weight aqueous solution of these acids or alkalis.
When the above is immersed in an aqueous alkali solution, smut is formed on the surface of the support, and in this case,
It is preferable to immerse in an acid such as phosphoric acid, nitric acid, sulfuric acid, and chromic acid, or a mixed acid thereof to perform desmut treatment.

A method for measuring the number of pores in a porous oxide film As a method for peeling only aluminum oxide (alumina) from an anodized aluminum support, a solution in which only aluminum is dissolved, for example, methanol saturation of iodine is used. There are a method of immersion in a solution and a method of reverse electrolysis.

In the reverse electro stripping method, aluminum oxide can be stripped from the aluminum surface by subjecting an aluminum support to a cathode (the anode is preferably a platinum or carbon electrode) and subjecting it to electrolytic treatment.

The separated aluminum oxide was converted to a high-resolution SEM (H
ITACHIS S-500).
The number in the range of 5 × 0.4 μm is measured at n = 5, and 1 μm
Convert to the number per ² and measure.

Hydrophilic treatment, boehmite treatment The aluminum support of the present invention may be subjected to a hydrophilization treatment during or after the anodic oxidation treatment.

The hydrophilic treatment includes US Pat. No. 3,181,
No. 461, hydrophilic metal cellulose described in U.S. Pat. No. 1,860,426, sodium arylsulfonate described in British Patent 2,098,627, Polyvinylphosphonic acid described in JP-A-46-35885, JP-B-6-942.
No. 34, JP-B-6-2436, amino acids and salts thereof, and hydroxyl-containing amines and salts thereof described in JP-B-5-32238, JP-A-62-1
No. 9494, JP-A-59-1016.
No. 51, a polymer compound containing a monomer unit having a sulfo group, a compound having an amino group and a phosphonic acid group or a salt thereof described in JP-A-63-165183 can be used.

On the other hand, the boehmite treatment is a hot water treatment,
Boiling water treatment, steam treatment, metal salt, etc., refers to treatment for producing crystalline hydrated oxide in pores.

These processes may be used in combination of two or more.

In the present invention, these treatments are preferably performed during the anodic oxidation treatment.

Anodizing As the electrolyte used in the anodizing treatment of the present invention, any electrolyte can be used as long as it forms a porous oxide film. Generally, sulfuric acid, phosphoric acid, oxalic acid, and chromic acid are used. Alternatively, the electrolysis is performed by direct current electrolysis using a mixed aqueous solution thereof.

A particularly preferred electrolyte in the present invention is formed by direct current electrolysis with sulfuric acid.

During electrolysis, the voltage is preferably 40 V or less, and more preferably the concentration, temperature and current density are adjusted so that anodic oxidation is performed in the range of 10 to 40 V.

The concentration of the electrolyte is 1 to 80% by weight,
More preferably, it is 5 to 50% by weight.

The liquid temperature is preferably 1 to 70 ° C., more preferably 5 to 40 ° C.

The current density is preferably 1 to 60 A / dm ^2, more preferably 1 to 20 A / dm ² .

The number of pores of the porous oxide film The anodic oxide film thickness is preferably 1 to 10 g / m ² , and 1.5 to 3.5 g / m ^2.
dm ² is more preferred.

The number of pores of the porous oxide film of the present invention is 400 to 700 / μm ² when observed from the surface.
Particularly preferably, the number is from 00 to 600 / μm ² . The number of holes at the interface between the oxide film and the aluminum support is 700 to 150.
0 / μm ² or less, and more preferably 800 to 1200 / μm ² .

In order to form the porous oxide film of the present invention, it is preferable to divide the anodic oxidation treatment into a plurality of treatments. The number of divisions is preferably in the range of 2 to 20, more preferably 2 to 12, and still more preferably 2 to 6.

As a method of division, a method of installing a plurality of processing tanks is preferable, and it is more preferable to provide a power supply for each processing tank in order to change the division processing conditions.

By providing a photosensitive composition layer on the lithographic printing plate support of the present invention, a lithographic printing plate or a photosensitive lithographic printing plate can be prepared. Examples of the photosensitive composition include Japanese Patent Application Nos. 08-151036 and 7-23144.
No. 4 is preferred.

[0054]

EXAMPLES The present invention will be described below in detail with reference to examples, but embodiments of the present invention are not limited thereto. In the text, “parts” means “parts by weight”.

(Preparation of Support 1) The surface of an aluminum plate (JIS1050, tempered H16) having a thickness of 0.24 mm was immersed in a 10% by weight aqueous sodium hydroxide solution at 50 ° C. for 20 seconds to perform a degreasing treatment and then washed with water. And neutralized with 10% sulfuric acid and washed with water.

Next, this aluminum plate was suspended in 20% by weight of an abrasive (alumina # 800) in water, and the amount of supply was 20%.
l / min, brush rotation speed 240 rpm, conveyance speed 2.0 m / min, mechanical surface roughening by brush polishing, washing with water, and then in a 6% sodium hydroxide aqueous solution kept at 85 ° C. for 20 seconds. After immersion, it was washed with water, immersed in a 10% sulfuric acid aqueous solution kept at 25 ° C. for 5 seconds, subjected to desmut treatment, and washed with water. 10 g of this aluminum plate
/ L hydrochloric acid aqueous solution, temperature 30 ℃, distance between poles 9m
m, current density 25 A / d using sine wave alternating current
The surface was electrochemically roughened at m ² and an amount of electricity of 150 C / dm ² , washed with water, immersed in a 1% aqueous solution of sodium hydroxide kept at 50 ° C. for 20 seconds, washed with water, and kept at 25 ° C. The resultant was immersed in a 10% sulfuric acid aqueous solution for 5 seconds, desmutted, washed with water, and dried.

Then, anodizing treatment was performed in a 20% sulfuric acid aqueous solution kept at 25 ° C. at a voltage of 10 V so that the oxide film became 25 mg / m ² , thereby producing a support 1.

(Preparation of Supports 2 to 9) A support was prepared in the same manner as the support 1 except that the anodic oxidation treatment was performed under the conditions shown in Table 1. Each voltage when anodic oxidation is divided into plural
1 to En.

FIG. 1 shows a schematic sectional view of the anodic oxidation apparatus at this time. Here, 1 is an aluminum plate, 2 is an electrode, 3 is an anodizing tank, and E1 to En are individual voltages when anodic oxidation is divided into a plurality. When the anodizing tank is divided into a plurality of units, the number of units within the dotted line is set to the number of divisions.

[0060]

[Table 1]

(Preparation of Supports 10 to 12)
3% at 70 ° C in 1% carboxymethylcellulose aqueous solution
The support was immersed for 0 second and subjected to a hydrophilization treatment to prepare a support 10.

The support 1 was immersed in a 1.0% aqueous solution of sodium silicate No. 3 at 70 ° C. for 30 seconds and subjected to silicate treatment to prepare a support 11.

The support 1 was immersed in pure water at 100 ° C. for 2 minutes and subjected to a boehmite treatment to prepare a support 12.

(Preparation of Supports 13 to 15) In the middle of the division anodizing treatment of the support 6 (between divisions 4 and 5), the same hydrophilic treatment and boehmite treatment as those of the supports 10 to 12 are applied. Thus, supports 13 to 15 were produced.

(Preparation of Supports 16 and 17) During the division of the support 7 in the division anodizing treatment (between divisions 6 and 7 and between 9 and 1)
0), a hydrophilic treatment and a boehmite treatment similar to those of the supports 10 to 12 are performed.
Was prepared.

Next, a coating solution of a photosensitive composition having the following composition was applied to these supports using a wire bar,
To obtain a photosensitive lithographic printing plate. At this time, the coating weight of the photosensitive composition after drying was 1.8 g / m ² .

[Photosensitive Composition] Esterification reaction product of 1,2-naphthoquinonediazide-5-sulfonyl chloride and 2,3,4-trihydroxybenzophenone 0.5 g phenol formaldehyde resin (weight average molecular weight: 2300) 2 0.0 g 2- (p-butoxyphenyl) -4,6-bis (trichloromethyl) -S-triazine 0.02 g naphthoquinone-1,2-diazide-4-sulfonic acid chloride 0.03 g crystal violet 0.01 g oil Blue # 603 (manufactured by Orient Chemical Industry Co., Ltd.) 0.015 g Ethylene dichloride 18 g 2-methoxyethyl acetate 12 g A weight of 100 was applied to the photosensitive lithographic printing plate thus obtained.
g, drawing was performed with a ballpoint pen, and after exposing for 50 seconds using a 3 kW metal halide lamp from a distance of 1 m through a transparent positive film in a vacuum firing frame, development was performed with the following developer.

A potassium silicate (SiO ₂ : 26 wt%, K 20: 13 wt%) 100 parts Potassium hydroxide (50% aqueous solution) 86 parts Phthalic acid 18 parts Beta-oxynaphthoic acid 18 parts Water 1513 parts Number of holes on oxide film surface The supports 1 to 14 that have been used are mounted on a high-resolution SEM (HITAC
HIS-500), a photograph taken at an observation magnification of 200,000 without applying a surface metal coat showed a 0.5 × 0.
The number in the range of 4 μm was measured at n = 5, and converted to the number per 1 μm ² for measurement.

The number of pores at the interface between the oxide film and the aluminum The support 1 to 14 was used as a cathode, and the oxide film was peeled off from the aluminum plate in a 20% aqueous sulfuric acid solution by a reverse electrolysis peeling method. The number of pores at the interface with the SEM (HITACHI S-5)
00), an observation magnification of 2 without the surface metal coating
From a photograph taken at a magnification of 100,000, the number in the range of 0.5 × 0.4 μm was measured at n = 5 and converted to the number per 1 μm ² for measurement.

Oxide film (aluminum oxide) by immersion in developer
The back surface of each of the produced supports 1 to 14 was sealed with an alkali-resistant sealing material, and immersed in a developer having the above composition maintained at 30 ° C. for 10 seconds to obtain a weight difference before and after immersion. The amount of oxide film (aluminum oxide) dissolved from was measured.

However, since the silicon oxide contained in the developing solution is adsorbed on the surface of the support after immersion in the developing solution and the weight increases, it is necessary to accurately measure the dissolution amount of the oxide film (aluminum oxide). The weight of the adsorbed silicon oxide was measured by measuring the intensity of silicon oxide on the surface of the support with a fluorescent X-ray analyzer and applying a predetermined amount of silicon oxide to the surface of the aluminum plate support prepared under the same conditions as the measurement sample. The weight of silicon oxide was quantified based on the calibration curve. Therefore, the amount of dissolution of the oxide film (aluminum oxide) by immersion in the developer is calculated from the following equation.

Dissolution weight of oxide film (aluminum oxide) [mg /
m ² ] = CD Here, symbols C and D are as follows: C: weight of silicon oxide formed on the surface of the support by immersion development [mg / m ² ] D: surface of the support after immersion development Weight change [mg
/ M ² ].

In C, when silicon is present on the surface of the support in advance by alkali metal silicate treatment or the like,
The increased weight based on the pre-existing silicon weight is used.

Residual film after development For the remaining film in the non-image area after development, the non-image area after development was measured for absorbance at 280 nm using a spectrophotometer.
The difference from the absorbance at 280 nm of the support before coating the photosensitive layer was measured.

Dropping of the photosensitive layer in the image area by drawing with a ball-point pen, adhesion of ink in the non-image area, and application of the smeared photosensitive layer, drawing with a ball-point pen with a load of 100 g, development, and adhesion of the ball-point pen ink in the non-image area Was evaluated.

Adhesion of the ballpoint pen ink in the non-image area after development is as follows: ：: no ink adhered Δ: slight ink adhered X: ink adhered

Next, after gumming, a printing machine (Mitsubishi DAIYA 1F-1) was used to evaluate whether or not the photosensitive layer in the image area had fallen off after printing 10000 sheets and adhesion of dirt on the non-image area.

Dropping of image portion Staining of non-image portion ：: Image portion is not dropped at all 描画: Drawing portion is not stained ：: Image portion is dropped slightly △: Ink is slightly attached × : The image area has been dropped. ×: Ink has adhered. Printing durability, soil recovery after standing, abrasion resistance After development, after gumming, printing machine (Mitsubishi DA)
After printing 10000 sheets in IYA 1F-1), printing is stopped and left for 24 hours. Thereafter, printing was started again, and the number of sheets until a normal printed matter was obtained without ink adhesion on the non-image area was evaluated to evaluate the recoverability after standing.

The printing durability was evaluated by the number of sheets until the image area was damaged and the inking failure occurred.

The abrasion resistance of the non-image area after printing 100,000 sheets was measured with a high-resolution SEM (HITACHI S-50).
According to 0), observation was performed at an observation magnification of 5000 times.

：: hardly worn △: slightly worn ×: worn

The results of the above measurements and evaluations are shown in Tables 2 and 3.

[0083]

[Table 2]

[0084]

[Table 3]

It can be seen that Examples 1 to 11 in the present invention have no problem in any of the characteristics, but Comparative Examples 1 to 6 outside the present invention have a problem in at least any of the characteristics.

[0086]

According to the present invention, even when the oxide film is a thin film, the physical strength is excellent, the dropout of the image area due to drawing with a ball-point pen, the scratching of the non-image area and the remaining ink are suppressed, the elution of the oxide film during development, A lithographic printing plate support in which the residual color of the layer is suppressed and a method for producing the same can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an anodizing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Aluminum plate 2 Electrode 3 Anodizing tank E1-En Individual voltage when anodic oxidation is divided into two or more

Claims (8)

[Claims] 1. A roughened and anodized aluminum support, wherein the number of pores on the surface of the oxide film is 400 to 700.
Pieces / [mu] m is ^2, the lithographic printing plate support hole number of the interface between the oxide film and aluminum characterized in that it is a 700 to 1500 pieces / [mu] m ^2. 2. The method for producing a lithographic printing plate support according to claim 1, wherein the roughened aluminum support is divided into a plurality of pieces when anodizing is performed. A method for producing a printing plate support. 3. The method according to claim 1, wherein when the roughened aluminum support is divided into a plurality of pieces when performing the anodizing treatment, different conditions are included in each of the anodizing treatment conditions. The method for producing a lithographic printing plate support according to claim 2. 4. The method for producing a lithographic printing plate support according to claim 2, wherein the number of divisions of the anodic oxidation treatment is in the range of 2 to 20. 5. When the number of divisions is n, the voltage E at the time of anodizing treatment is E1 ≧ E2... ≧ En, and E1 is 20 to
5. The method for producing a lithographic printing plate support according to claim 2, wherein the anodic oxidation treatment is performed n times from 1 so as to be 40 V and En is 10 to 20 V. 6. The oxide film on the surface has a pore number of 400 to 700.
A number / [mu] m ^2, pore number of the interface between the oxide film and the aluminum is 700 to 1500 cells /, characterized in that [mu] m is ² claim 2, 3, 4 or 5 lithographic printing plate support according Production method. 7. The lithographic printing plate support according to claim 2, wherein when the anodic oxidation treatment is divided into a plurality of treatments, a hydrophilic treatment is performed during the division. Production method. 8. The lithographic printing plate support according to claim 2, wherein when the anodic oxidation treatment is divided into a plurality of parts, a boehmite treatment is performed during the division. Production method.