JPH0214187A - Manufacture of aluminum support for lithographic printing plate - Google Patents

Abstract

PURPOSE:To prevent the occurrence of stain in a non-image part substantially and to enable the execution of lithographic printing endurable to a great number of sheets of print under a high-speed or severe printing condition, by a method wherein an aluminum plate is subjected to mechanical surface-roughing and/or chemical surface-roughing, an anodized film is provided in succession and thereafter the plate is subjected to an electrolytic surface-roughing processing. CONSTITUTION:The cleaned surface of an aluminum plate is subjected to mechanical surface- roughing and/or chemical surface-roughing. As for a method of mechanical surface-roughing, a brush grain method is preferable particularly, since it enables execution of stable sand grinding in terms of manufacture. As for a method of chemical surface-roughing, a hydrofluoric acid/ammonium fluoride method, a hydrochloric acid method, a hydrochloric acid/ferrous chloride method or the like is used. The surface roughness (central-line average roughness) of the surface of aluminum subjected to sand grinding is preferably within a range of 0.3 to 7mum. On the surface of aluminum subjected to mechanical surface-roughing and/or chemical surface-roughing, an anodized film is provided in a water solution containing a sulphuric acid. The thickness of the film is preferably 0.001 to 0.5g/m<2>. Subsequently, an electrolytic surface-roughing processing is executed by using an alternating waveform current, with a water solution of a nitric acid of concentration 9/gl used as an electrolyte.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing an aluminum support for a lithographic printing plate, and in particular to an aluminum plate containing (a) e! & Mechanical surface roughening treatment and/or chemical surface roughening treatment, (b) anodization treatment in an aqueous solution containing sulfuric acid, and (c) electrolytic surface roughening treatment in an acidic electrolyte solution are performed in this order. The present invention relates to a method for producing an aluminum support for a lithographic printing plate, characterized in that:

[Conventional technology]

Conventionally, aluminum plates have been widely used as supports for lithographic printing plates, but in order to improve the adhesion between the support and the optical layer and to provide water retention to non-image areas, the surface of the support has been roughened. A so-called graining process is performed.

Specific methods for this graining include sandblasting,
Mechanical graining methods include ball graining, wire graining, brush graining using a nylon brush and abrasive/water slurry, and honing graining in which an abrasive/water slurry is sprayed onto the surface at high pressure. Alternatively, there is a chemical graining method in which the surface is roughened using an etching agent made of a mixture thereof. Further, the electrochemical graining methods described in JP-A-54-146234 and JP-B-48-28123, for example, JP-A-53-123204,
A method that combines the mechanical graining method and the electrochemical graining method described in Japanese Patent Application Laid-Open No. 56-552
A method combining the mechanical graining method described in Japanese Patent No. 91 with the chemical graining method using a saturated aqueous solution of an aluminum salt of a mineral acid is also known.

Among these surface roughening treatment methods, electrolytic surface roughening treatment is known as a method that allows easy control of the rough surface shape and provides a finely roughened surface.

In such electrolytic surface roughening treatment, the adhesion between the support and the irradiation layer is improved, and a large number of printable printed matter (hereinafter referred to as
In order to obtain a high number of sheets (called the number of printing sheets), it is possible to obtain a deep grain shape by inputting a large amount of electricity of several hundreds of corons or more, but the large grain size of 10 μm or more produced by electrolytic surface roughening treatment It has the disadvantage that the bits cause stains in non-image areas. Furthermore, large bits of 10 μm or more have the disadvantage of reducing the number of printed sheets under high-speed or severe printing conditions such as rotary offset printing.

Furthermore, a rough surface uniformly provided with small bits of 0.5 μm or less is less likely to cause stains in non-image areas during printing, but has the drawback of decreasing the number of printed sheets.

[Problems to be Solved by the Invention] Therefore, the object of the present invention is to provide a lithographic printing plate that is less likely to cause stains in non-image areas and that can withstand a large number of prints under high-speed or harsh printing conditions such as rotary offset printing. An object of the present invention is to provide a method for manufacturing an aluminum support.

Furthermore, another object of the present invention is to provide a method for producing a support for a lithographic printing plate, which uses a small amount of electricity during electrolytic surface roughening treatment and has a long printing life.

[Means to solve the problem]

As a result of various studies in view of the problems of the prior art as described above, the inventors of the present invention have found that after mechanically roughening and/or chemically roughening an aluminum plate, an aqueous solution containing sulfuric acid is subsequently applied. The inventors have discovered that the above object can be achieved by providing an anodic oxide film therein and subsequently performing an electrolytic surface roughening treatment, and have completed the present invention.

The present invention will be explained in detail below.

The aluminum plate used in the present invention includes a pure aluminum plate and an aluminum alloy plate. Various aluminum alloy plates can be used, such as F
e5Si, Cu, Mn, MgbCr, Zn, Ti
An alloy plate of aluminum and a metal such as , Pb 2 or Ni is used. For example, as commercially available aluminum, JI
An aluminum plate made of SA 1050 material, 1100 material, 3003 material, etc. is used.

In carrying out the present invention, it is preferable to first perform a cleaning treatment to remove oil, rust, dirt, etc. adhering to the surface of the aluminum plate. As this cleaning treatment, for example, trichlorethylene (triclene)
This includes solvent degreasing using eg, alkaline etching degreasing using caustic soda or the like. When degreasing with alkaline etching such as caustic soda, smut is generated, so in order to remove this, a desmut treatment (for example, immersion in 10 to 30% nitric acid) is usually applied after washing with water. be.

The surface of the cleaned aluminum plate is subjected to mechanical roughening and/or chemical roughening treatment.

Any method such as brush graining, sandblasting, boulder graining, wire graining, or honing graining may be used as the mechanical surface roughening method, but the brush graining method is particularly effective in producing stable graining in terms of production. Therefore, it is preferable.

Alternatively, a chemical surface roughening method using an alkali or acid, or a method that combines a mechanical surface roughening method and a chemical surface roughening method may be used. Chemical surface roughening methods include hydrofluoric acid/ammonium fluoride method, hydrochloric acid method, hydrochloric acid/aluminum chloride method, hydrochloric acid/iron chloride method, etc. These etchants include phosphoric acid, boric acid, oxalic acid, etc. Additives and surfactants may also be added.

The surface roughness (center line average roughness) of the grained aluminum surface is preferably in the range of 0.3 to 0.7 μm. If the surface roughness is greater than 0.7 μm, stains will easily occur in non-image areas. On the other hand, if the surface roughness is less than 0.3 μm, the number of printing sheets will decrease.

As a representative example, the brush grain method, which is a mechanical surface roughening method, is used to explain the surface roughness of 0.3 to 0.7 μm.
The brush grain conditions are as follows: Pumice particle size is 10 to 80 μm (average 30 μm), water slurry is approximately 20%, nylon brush thickness is 480 μm, and pressure for pressing against aluminum plate is 3.3 Kw. , rotation speed 300r
pm is common.

Grained aluminum plates may be etched with alkali or acid if necessary after washing with water.The optimum amount of dissolution (etching amount) of the aluminum plate varies depending on the surface roughness of the grain, but depending on the surface roughness, The etching amount when the thickness is 0.5 μm is preferably 2 to 10 glrd. When the amount of etching becomes large, the grained surface is destroyed and the number of prints that can be printed decreases.On the other hand, when the amount of etching becomes small, bums remain, causing stains on non-images. As conditions for alkaline etching, for example, if immersion treatment is carried out in a mixed solution of 28% by weight of sodium hydroxide and 10% by weight of aluminum ions at a temperature of 60°C for 6 to 40 seconds, the etching can be performed from 2 to Lo.
An etching amount of g/rrl is obtained.

Generally, when alkali etching is performed, smut is generated, so a desmutting process is performed to remove the smut. As a desmut treatment, for example, nitric acid 1
0 to 30% by weight liquid at a temperature of 10 to 30°C, 10 to 30% by weight.
A 60 second immersion treatment is sufficient.

An anodic oxide film is provided on the mechanically roughened and/or chemically roughened aluminum surface in an aqueous solution containing sulfuric acid. The thickness of the coating is preferably o,oot ~ 0.5 g/rd; when it is less than 0.001 g/%, the effect of forming deep pits according to the present invention decreases; As the thickness increases, the bit diameter increases and becomes rougher.

The concentration of sulfuric acid solution in anodizing treatment is 10 to 500
gll is preferable; if the concentration is thinner than 10 g/g, the bits generated by the electrolytic surface roughening treatment will become non-uniform;
At a density higher than 00 gll, deep focus is no longer generated. In the above sulfuric acid solution, 0.01 to 50 A/dm"
An amount of electricity in the range of 0.5 to 10 coulombs/da'' is applied to the surface with a flow rate of 0.001 g/rrf to 0.00 g/rrf.
An oxide film of 5 g/rrf can be provided.

If an anodic oxide film is provided after mechanical roughening and/or chemical roughening in this way, it can be used for lithographic printing plates that have a long print life even if the amount of electricity used for electrolytic roughening is reduced as described later. A support can be obtained.

As the electrolytic solution used in the electrolytic surface roughening treatment, any one used in ordinary AC electrolytic etching can be used. Particularly preferred are an aqueous solution containing 2 to 40 gll of nitric acid, a solution containing 2 to 40 gll of hydrochloric acid, or an aqueous solution containing 2 to 40 gll of both in total. As the concentration becomes lower than 2 g/l, the efficiency of roughening the surface of the aluminum plate by electrolytic etching decreases, and on the other hand, as the concentration becomes higher than 40 g/l, pure chemical etching by acid occurs. As a result, the roughened surface becomes uneven.

The temperature ranges from normal temperature to 70°C, preferably from normal temperature to 70°C.
The temperature range is 50°C. Further, corrosion inhibitors such as carboxylic acids, amines, aldehydes, etc. may be added.

The current used for electrolytic surface roughening treatment is commercial alternating current or
Alternating waveform currents such as (al sine wave, (b) square wave, FC1 trapezoidal wave, etc. shown in the figure) can also be used in the present invention.The current density is preferably in the range of 10-200 A/dm2, and the IOA When the electrolysis time is lower than 200A/d11!, pit formation becomes extremely difficult to occur, and above 200A/d11!, it becomes difficult to control uniform pit formation.The electrolysis time varies depending on the current density, but when the current density is IOA/da The treatment may be performed for 5 to 30 seconds, and when the current density is 200 A/dm, the treatment may be performed for 1 to 4 seconds.

The present invention can be carried out by either batch processing or continuous processing. For example, in continuous processing, a resistive film forming treatment tank, a water washing tank, and an electrolytic surface roughening treatment tank are arranged in this order, and the aluminum web is continuously processed. This is done by allowing the material to pass through and be processed.

It is preferable to chemically clean the electrolytically roughened aluminum plate, since this has the effect of removing so-called smut, which is surface residue, from the surface. Details of such a cleaning process can be found in U.S. Patent No. 3,83
4.998 and Japanese Patent Publication No. 56-11316. If necessary, special public Sho 4B-28123
Alkaline etching treatment as described in the above publication may be performed.

When the aluminum plate treated as described above is used as a lithographic printing plate support, it has good water retention, adhesion with the photosensitive layer,
In order to improve the mechanical strength of the surface of the non-image area, anodization treatment may be further performed to form an oxide film on the surface of the aluminum plate.

The anodic oxidation treatment can be performed according to conventionally known methods. For example, the electrolytic solution is sulfuric acid, phosphoric acid, oxalic acid, amidosulfonic acid, sulfosalicylic acid, a mixture thereof, or an aqueous solution of these containing Al1- ions, and the anodization treatment is performed mainly using direct current. This may be done using alternating current or a combination of these currents. Electrolytic rR concentration is 1 to 80%, temperature is 5 to 70°C, current density is 0.5 to 60 A/dm, and oxide film weight is 0.3 to 70°C.
5 g/% is preferred.

The anodized aluminum plate is further coated with U.S. Patent Tube 2.7.
No. 14,066 and U.S. Pat. No. 3,181,461, by immersion in an aqueous solution of an alkali metal silicate, such as sodium silicate; As described in U.S. Pat. It may also be treated with polyvinylphosphonic acid as described in No. 461.

On the lithographic printing plate support obtained in this way,
A photosensitive lithographic printing plate can be obtained by providing a conventionally known photosensitive layer as a photosensitive layer of a PS plate (abbreviation for Pre-Sensitized Plate), and a lithographic printing plate obtained by platemaking processing of this plate is , has excellent performance.

The composition of the above-mentioned photosensitive layer includes the following.

(A) Photosensitive layer consisting of diazo resin and binder: As a negative-working photosensitive diazo compound, U.S. Pat.
Diphenylamine, which is a reaction product of the diazonium salt disclosed in the specifications of No. 3,631 and No. 2,667.415, and an organic condensing agent containing a reactive carbonyl group such as aldol or acecul. A condensation product of p-diazonium salt and formaldehyde (so-called photosensitive diazo resin) is preferably used. Other useful condensed diazo compounds are disclosed in Japanese Patent Publication No. 49-48001 and Japanese Patent Publication No. 49-48001.
It is disclosed in publications such as No. 45322 and No. 49-45323. These types of photosensitive diazo compounds are usually obtained in the form of water-soluble inorganic salts and can therefore be coated from aqueous solution. Further, these water-soluble diazo compounds are reacted with an aromatic or aliphatic compound having one or more phenolic hydroxyl groups, sulfonic acid groups, or both by the method disclosed in Japanese Patent Publication No. 47-1167, The reaction product, a substantially water-insoluble photosensitive diazo resin, can also be used.

It can also be used as a reaction product with hexafluorophosphate or tetrafluoroborate as described in JP-A-56-121031.

Examples of reactants with phenolic hydroxyl groups are diphenolic acids such as hydroxybenzophenone, 4,4-bis(4'-hydroxyphenyl)pentanoic acid, resorcinol, or diresorcinol, which further contain 1IfA groups. It may have. Hydroxybenzophenone includes 2゜4-dihydroxybenzophenone, 2
-Hydroxy-4-methoxybenzophenone, 2,2'
-dihydroxy-4,4'-dimethoxybenzophenone or 2,2',4,4'-tetrahydroxybenzophenone. Preferred sulfonic acids include aromatic sulfonic acids such as sulfonic acids such as benzene, toluene, xylene, naphthalene, phenol, naphthol and benzophenone, or soluble salts thereof, such as ammonium and alkali metal salts.

Sulfonic acid group-containing compounds are generally optionally substituted with lower alkyl, nitro groups, halo groups, and/or another sulfonic acid group; preferred examples of such compounds include benzenesulfonic acid, toluenesulfonic acid, acid,
Naphthalene sulfonic acid, 2゜5-dimethylbenzenesulfonic acid, sodium benzenesulfonate, naphthalene-
2-sulfonic acid, 1-naphthol-2 (or 4)-sulfonic acid, 2゜4-dinitro-1-naphthol-7-sulfonic acid, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, m (p Examples include sodium '-anilinophenylazo)benzenesulfonate, alizarinsulfonic acid, o-toluidine-m-sulfonic acid, and ethanesulfonic acid. Sulfonic esters of alcohols and their salts are also useful. Such compounds are usually readily available as anionic surfactants. Examples include ammonium or alkali metals such as lauryl sulfate, alkylaryl sulfate, p-nonylphenyl sulfate, 2-phenylethyl sulfate, and inoctylphenoxyjethoxyethyl sulfate.

These substantially water-insoluble photosensitive diazo resins can be isolated as a precipitate by mixing the water-soluble photosensitive diazo resin and an aqueous solution of the aromatic or aliphatic compound, preferably in approximately equal amounts. It will be done.

Also preferred are the diazo resins described in GB 1,312,925.

The most preferred diazo resin is 2-methoxy-4-condensate of p-diazodiphenylamine and formaldehyde.
Hydroxy-5-benzoylbenzene sulfonate.

The appropriate content of the diazo resin in the photosensitive layer is 5 to 50% by weight. As the amount of diazo resin decreases, photosensitivity naturally increases, but stability over time decreases. The optimum amount of diazo resin is about 8-20% by weight.

On the other hand, various polymer compounds can be used as the binder, but in the present invention, hydroxy, amine,
Carboxylic acids, amides, sulfonamides, activated methylene,
Those containing groups such as thioalcohol and epoxy are desirable. Such preferred binders include those described in British Patent Nos.
350,521, British Patent No. 1.460,978 and U.S. Pat. No. 4,12
Polymers containing hydroxyethyl acrylate units or hydroxyethyl methacrylate units as the main repeating unit as described in U.S. Pat. No. 3,276, polyamides as described in U.S. Pat. No. 3,751,257 resins, phenolic resins as described in British Patent No. 1,074,392 and polyvinyl acecool resins such as polyvinyl formal resins, polyvinyl butyral resins, U.S. Pat. No. 3,660
, 097, linear polyurethane resins, polyvinyl alcohol phthalate resins, epoxy resins condensed from bisphenol A and epichlorohydrin, and amino group-containing resins such as polyaminostyrene and polyalmylamino (meth)acrylate. and cellulose derivatives such as cellulose acetate, cellulose alkyl ether, and cellulose acetate phthalate.

The composition of diazo resin and binder may further include a pt+ indicator as described in British Patent No. 1.041.463, as described in U.S. Pat. No. 3,236,646. Additives such as phosphoric acid and dyes can be added.

(B) Photosensitive N consisting of an o-quinonediazide compound:
Particularly preferred 0-quinonediazide compounds are 0-naphthoquinonediazide compounds, such as those described in U.S. Pat.
．． No. 118, No. 2,767.092, No. 2,772
, No. 972, No. 2,859,112, No. 2.90
No. 7.665, No. 3,046.110, No. 3.0
No. 46.111, No. 3.046,115, No. 3.
No. 046.118, No. 3,046,119, No. 3
, 046.120, 3.046.121, 3.046,122, 3.046.123, 3,061,430, 3,102,809 ,
It is described in numerous publications including the specifications of the same No. 3,106,465, the same No. 3,635.709, and the same No. 3,647,443, and these are preferably used. I can do it. Among these, O-naphthoquinonediazide sulfonic acid ester or O-naphthoquinonediazidecarboxylic acid ester of an aromatic hydroxy compound, and O-naphthoquinonediazide sulfonic acid amide or O-naphthoquinonediazidecarboxylic acid amide of an aromatic amino compound are particularly preferred. , especially U.S. Pat. No. 3,635,70
No. 9, the condensate of pyrogallol and acetone is reacted with O-naphthoquinonediazide sulfonic acid to form an ester, and U.S. Pat. ester reaction of O-naphthoquinonediazide sulfonic acid or O-naphthoquinonediazidecarboxylic acid to a polyester having a group, and a homopolymer of p-hydroxystyrene as described in British Patent No. Polymers or copolymers of copolymerizable monomers with 0-naphthoquinonediazide sulfonic acid or 0-naphthoquinonediazidecarboxylic acid are ester-reacted, as described in U.S. Pat. No. 3,759,711. A copolymer of p-aminostyrene and other copolymerizable monomers, such as the one described above, subjected to an amide reaction with 0-naphthoquinonediazide sulfonic acid or 0-naphthoquinonediazidecarboxylic acid is very excellent.

These 0-quinonediazide compounds can be used alone, but it is preferable to use them in combination with an alkali-soluble resin. Suitable alkali-soluble resins include novolak-type phenolic resins, and specifically, , phenol formaldehyde resin, 0-cresol formaldehyde resin, m-cresol formaldehyde resin, and the like. Additionally, as described in U.S. Pat. No. 4,123,279, along with phenolic resins such as those described above,
The alkali-soluble resin, which is even more preferable when used in combination with a phenol substituted with an alkyl group having 3 to 8 carbon atoms such as t-butylphenol formaldehyde resin or a condensate of formaldehyde with cresol, is a composition constituting the photosensitive layer. The content is about 50 to about 85% by weight, more preferably 60 to 80% by weight, based on the total weight of.

A photosensitive composition comprising an 0-quinonediazide compound includes
If necessary, further dyes and plasticizers, such as British Patent Tube 1,
Additives can be added, such as components that provide printout performance, such as those described in U.S. Pat. No. 401,463, U.S. Pat.

(C) Photosensitive layer consisting of an azide compound and a binder (high molecular compound, e.g. British Patent No. 1.235.281, British Patent No. 1.49)
Specifications of No. 5.861 and JP-A-51-32331
In addition to the compositions comprising an azide compound and a water-soluble or alkali-soluble polymer compound described in JP-A No. 51-36128, JP-A No. 50-5102, JP-A-50-50-
No. 84302, No. 50-84303, No. 53-129
Included are compositions consisting of a polymer containing an azide group and a polymer compound as a binder, as described in each publication of No. 84.

(D) Other photosensitive resin layers For example, polyester compounds disclosed in JP-A-52-96696, British Patent No. L112,277, British Patent No. 1.313.390, British Patent No. 1,341,004. issue,
Polyvinyl cinnamate resins described in specifications such as No. L377.747, U.S. Patent No. 4,072,528
This includes the photopolymerizable photopolymer compositions described in the specifications of No. and No. 4,072,527.

It also includes the case where an electrophotographic light-sensitive material disclosed in JP-A-60-107042 is used.

The amount of photosensitive layer provided on the support is about 0.1 to about 1 g.
/rd, preferably 0.5-4g/n? is within the range of

After the PS plate is imagewise exposed, a resin image is formed by processing including development using conventional methods. For example, a photosensitive layer (8) comprising a diazo resin and a binder
In the case of S plates, after image exposure, e.g.
The unexposed portions of the photosensitive layer are removed by development with a developer as described in US Pat. No. 86,006 to obtain a lithographic printing plate. In addition, in the case of a PS plate having a photosensitive layer (B), after image exposure, the exposed portion is removed by developing with an alkaline aqueous solution as described in U.S. Pat. No. 4,259.434. A lithographic printing plate is obtained.

〔Effect of the invention〕

The structure of the present invention is to provide an anodic oxide film in an aqueous solution containing sulfuric acid after mechanically roughening and/or chemically roughening an aluminum plate, and then electrolytically roughening the aluminum plate in an acidic electrolyte. It has now become possible to provide a method for producing an aluminum support for a lithographic printing plate, which does not cause contamination in non-image areas and has excellent stiffness resistance even under high-speed or severe printing conditions such as in rotary offset printing.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to these Examples.

Note that "%" indicates "polymerization %" unless otherwise specified.

Example 1 An aluminum plate (JISA1050 material) with a thickness of 0.24 mm was placed in a 10% aqueous sodium hydroxide solution at 50°C for 20 minutes.
After immersion for seconds and degreasing/cleaning treatment,
It was washed with water and then neutralized with a 10% aqueous nitric acid solution. After washing with water, a rotating nylon brush (
The surface was grained (brush grained) with a thickness of 480 μm and a rotation speed of 30 Orpm+. The surface roughness at this time (
The center line average roughness) was 0.5 μm. After washing with water, 10
% caustic soda aqueous solution heated to 70° C. and etched for 12 seconds so that the amount of aluminum dissolved was 6 g/m. After washing with water, it was immersed in a 30% nitric acid aqueous solution at room temperature for 1 minute to neutralize it, and then thoroughly washed with water.

Subsequently, anodic oxidation treatment was performed in a 15% (270 g/l) sulfuric acid aqueous solution at room temperature using direct current at LA/ds", 4 clones/d@" to form a thin anodic oxide film (approximately 0.05 g/l).
g/ryf) and then washed with water.

Next, an electrolytic surface roughening treatment was performed using an aqueous nitric acid solution having a concentration of 9 g/l as an electrolyte and an alternating waveform current shown in FIG. 1(b). The electrolytic conditions were as follows: electrolytic surface roughening treatment was carried out for 10 seconds at a frequency of 6011z and an anode current density of 40 A/ds;
It was immersed in a 20% sulfuric acid aqueous solution for 1 minute to dissolve and remove it.

This aluminum plate was anodized at 3 A/da in a 15% sulfuric acid aqueous solution at 30°C using direct current until the weight of the anodized film was 2.
g1rd for 1.5 minutes, washed with water, immersed in a 3% sodium silicate aqueous solution at 70°C for 20 seconds, washed with water, and dried.

A photosensitive solution having the following composition was applied to the support thus obtained and dried to provide a photosensitive layer. The dry coating amount of the photosensitive layer is 2
．． It was Og/rd.

Photosensitive liquid After exposing the thus prepared photosensitive lithographic printing plate through a negative image film using a metal halide lamp as a light source,
The plate was developed using a standard solution of negative PS plate developer DN-3C manufactured by Fuji Photo Film Co., Ltd., and further gummed to obtain a lithographic printing plate.

After 30 minutes, ink (Toyo Ink II! 1 Web Ki
ng Sumi) and dampening water (EU-31 manufactured by Fuji Photo Film ■)
Using a standard printing pressure of 40.0 times diluted solution), a standard printing pressure of 40. Printed at a speed of oooo pages/hour. The printing plate life of the lithographic printing plate thus obtained was 120,000 sheets. Furthermore, there was no contamination in the non-image area.

Example 2 Example 1 was repeated, except that the surface on which the anodic oxide film was provided before the electrolytic roughening treatment was subjected to electrolytic roughening treatment for 5 seconds under the same conditions as in Example 1. Printing durability is 1
It was 20,000 pieces. Furthermore, there was no contamination in the non-image area.

Example 3 The method of Example 1 was followed up to the electrolytic surface roughening treatment, and after washing with water, it was immersed for about 1 second in a 10% caustic soda aqueous solution heated to 70°C to reduce the aluminum dissolution amount to 0.5 g/rr? I etched it to make it look like this. After washing with water, it was immersed in a 30% nitric acid aqueous solution for 30 seconds to neutralize it, and after thoroughly washing with water, an anodized film and a photosensitive layer were further provided by the method of Example 1. When printed in the same manner as in Example 1, the number of prints was 120,000.
It was 1 piece.

Furthermore, there was no contamination in the non-image area.

Example 4 Electrolytic surface roughening treatment was performed on the surface on which an anodized film was provided before electrolytic surface roughening treatment using hydrochloric acid 5 g/j! Example 1 was repeated, except that the test was carried out for 20 seconds at a frequency of 60 Hz and an anode current density of 30 A/d n (20 seconds) using an alternating waveform current shown in FIG. 2(b) in an electrolytic solution containing The number of printing sheets was 120,000 sheets.Furthermore, there was no contamination in the non-image area.

Comparative Example 1 The treatment described in Example 1 was performed without performing anodization treatment before electrolytic surface roughening treatment. The number of printing sheets is so, ooo
It was 1 piece. Contamination in the non-image area was slightly more than in Example 1.

Comparative Example 2 The treatment described in Example 2 was performed without performing the anodization treatment before the electrolytic surface roughening treatment. Printing durability is 60.00
There were 0 pieces. There was no contamination of non-image areas.

Comparative Example 3 The treatment described in Example 4 was carried out without performing the anodization treatment before the electrolytic surface roughening treatment. The number of printing sheets is ao, oo
There were o pieces. Contamination in the non-image area was slightly more than in Example 4.

Comparative Example 4 The treatment described in Example 1 was carried out without mechanical roughening (brush graining). Printing durability is 100.00
There were 0 pieces. There was no contamination of non-image areas.

Comparative Example 5 The treatment described in Example 1 was carried out, except that the anodization treatment before the electrolytic surface roughening treatment and the electrolytic surface roughening treatment were not performed (brush grain only). The number of printing sheets is 50,
It was 000 pieces. The non-image area was highly contaminated.

Comparative Example 6 Except for brush grain and electrolytic roughening treatment without anodizing treatment before electrolytic roughening treatment,
The treatment described in Example 1 was carried out.

The printing durability was 60,000 sheets. Contamination in the non-image area was higher than in Example 1.

Example 5 Mechanical roughening treatment with honing grain (aluminum oxide 4
Powder of 0 to 50 μm was sprayed with high-pressure water to form a grain chamber. The surface roughness at this time was 0.5 μm. Example 1 was repeated except as was done in ). The printing durability was 120,000 sheets. There was no contamination of non-image areas.

Example 6 Instead of mechanical roughening treatment, chemical roughening treatment (surface roughening treatment was performed by immersing it in a 3% ammonium fluoride aqueous solution at room temperature for 5 minutes. The surface roughness at this time was 0. Example 1 was repeated except that the diameter was .5 μm. The printing durability was 120,000 sheets. There was no contamination of non-image areas.

The processing conditions and printing results of Examples 1 to 6 and Comparative Examples 1 to 6 are shown in the table.

In addition, although the above example shows the case of a combination of a negative-tone photosensitive layer and a support subjected to surface roughening treatment according to the method of the present invention, the same effect was obtained in combination with a positive-tone photosensitive layer. .

[Brief explanation of the drawing]

FIGS. 1(a), (b), and (c) show voltage waveforms of alternating waveform currents used when electrolytically roughening the aluminum support of the present invention. (b)

Claims (1)

[Claims] It is characterized in that after mechanically roughening and/or chemically roughening an aluminum plate, an anodic oxide film is provided in an aqueous solution containing sulfuric acid, followed by electrolytic roughening treatment in an acidic electrolyte. A method for producing an aluminum support for a lithographic printing plate.