JPH03215098A - Manufacture of support for planographic printing plate - Google Patents

Abstract

PURPOSE:To make the reproduction of a dot excellent and to make the contamination of a non-image part hard to generate by applying surface roughening and anodic oxidation to the surface of an aluminium plate before applying dyeing treatment and sealing treatment thereto in this order. CONSTITUTION:Prior to applying anodic oxidation to an aluminum plate, the surface of the aluminum plate is subjected to degreasing treatment for removing the rolling oil on the surface thereof if desired and subsequently subjected to surface roughening and anodic oxidation treatment in succession. The surface provided with an anodic oxidation film is continuously subjected to dyeing treatment and sealing treatment in succession. The support thus subjected to anodic oxidation, dyeing and sealing in succession has halation preventing effect. By this method, excellent tone reproduction is shown and printing contamination becomes hard to generate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a support for a lithographic printing plate, and particularly to a method for producing a rough aluminum plate for a lithographic printing plate.

(Prior art) Photosensitive lithographic printing plates (so-called PS plates), in which a photosensitive composition is coated in a thin layer on aluminum, are produced using mechanical methods such as the brush grain method or boulder rain method. After roughening the surface using an electrochemical method such as the electrolytic grain method or a method that combines both methods, the surface is made into a matte finish, and then processed with an aqueous solution of acid or alkali, and then anodized. After the treatment, a hydrophilic treatment is performed if desired, and a photosensitive layer is provided thereon to produce the photosensitive layer.

This PS plate is usually subjected to image exposure, development, correction, and gumming processes to form a lithographic printing plate, which is then mounted on a printing machine and printed.

However, in the image area of a lithographic printing plate obtained by imagewise exposure of a positive-working PS plate in which a positive-working photosensitive layer is provided on a conventionally known lithographic printing plate support, the halftone dot size is the same as that of the original. This has the disadvantage that the size is smaller than the halftone dot size, and therefore the reproducibility of highlighted areas is poor. In addition, the image area of a lithographic printing plate obtained by imagewise exposing a negative-tone PS plate in which a negative-tone photosensitive layer is provided on a conventionally known lithographic printing plate support has a halftone dot size that is the same as that of the original. The size of the dots is larger than that of the dots, and therefore the halftone dots in a portion of the shadow tend to collapse.

In order to solve this problem, for example, Japanese Patent Laid-Open No. 61-1226
No. 49 discloses that on an anodized aluminum plate,
It has been proposed to provide a positive-working photosensitive layer after subbing with an antihalation dye.

British Patent No. 1,069,283 proposes applying a photosensitive layer by anodizing and then undercoating with dichromate, alkali metal silicate, or paint. Additionally, U.S. Pat. No. 4,277. No. 555 proposes a method in which after anodic oxidation, the material is subjected to hydrophilic treatment to be negatively charged, and then ionically dyed with a cationic dye.

JP-A No. 6Q-64352 proposes a method in which an aluminum plate is roughened and made hydrophilic, and then colored with a monobasic acid type acid dye.

JP-A-58-14797 proposes a method in which an aluminum plate is roughened and subjected to alkali etching, and then a colored anodic oxide film is formed thereon.

All of these methods have the disadvantage that the dye tends to move into the photosensitive layer when the photosensitive layer is coated, resulting in a decrease in its function as an antihalation layer. Therefore, in order to improve the halftone dot reproducibility, it is necessary to use a large amount of dye, but in this case, there is a drawback that the dye remains in the non-image area, which tends to cause stains during printing.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide excellent halftone dot reproducibility, less contamination of non-image areas, ink stain recovery ability, and easy balance between water and ink. An object of the present invention is to provide a method for producing a support for a lithographic printing plate, which is suitable for producing a lithographic printing plate having excellent performance and high printing durability.

(Means for Solving the Problem) In order to achieve the above object, the present inventors have made the present invention as a result of intensive studies. and anodizing, followed by (a) dye staining treatment, Q)) pore sealing treatment, and if necessary, (c) hydrophilization treatment, in this order.

Hereinafter, the present invention will be explained step by step.

(Aluminum Plate) The aluminum plate used in the present invention is a plate-shaped body such as pure aluminum or an aluminum alloy containing aluminum as a main component and a trace amount of foreign atoms.

Such foreign atoms include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel, and titanium. The content of these foreign atoms is generally 10% by weight or less. Aluminum suitable for the support of the present invention is pure aluminum, but since it is difficult to produce completely pure aluminum due to refining technology, it is preferable to use aluminum that contains as few foreign atoms as possible. As described above, the aluminum plate applied to the present invention is not limited in its composition, and can be made of conventionally known and publicly used materials (for example, JISA105
0. JIS AIIOO, JIS Al200,
JIS A3103, JISA3003. JIS
A5005, etc.) can be used as appropriate.

The thickness of the aluminum plate used in the present invention is 0. 1
mII1-0. Approximately 5 mm is appropriate.

(Surface Roughening Treatment) Before the surface of the aluminum plate is anodized, it is optionally degreased with a surfactant or an alkaline aqueous solution to remove rolling oil from the surface. The surface is roughened.

Surface roughening methods include a method of mechanically roughening the surface, a method of electrochemically roughening the surface, and a method of selectively dissolving the surface chemically. As a method for mechanically roughening the surface, known methods such as ball polishing, brush polishing, sandblasting, honing and the like can be used. Further, as an electrochemical surface roughening method, there is a method in which alternating current or direct current is used in a hydrochloric acid or nitric acid electrolyte. Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 54-63902, a method combining mechanical surface roughening and electrochemical surface roughening can also be used.

The aluminum plate thus roughened is subjected to alkali etching treatment and neutralization treatment as necessary.

(Anodizing Treatment) The surface treated in this manner is subsequently subjected to an anodizing treatment.

The electrolyte used for anodizing the aluminum plate may be anything as long as it forms a porous oxide film, and generally sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or a mixed acid thereof, sodium hydroxide, or hydroxide is used as the electrolyte. Potassium or a mixture thereof, ammonium fluoride addition bath, etc. are used, and the electrolyte added thereto and its concentration are appropriately determined depending on the type of electrolyte. The processing conditions for anodic oxidation vary depending on the type of electrolyte, so they cannot be specified, but generally the electrolyte concentration is 1-80% by weight solution, the liquid temperature is 5-80°C, and the current density is 5-80 A. /dm
2. A voltage range of 1 to 100 V and an electrolysis time of 5 seconds to 10 minutes are appropriate.

A particularly preferred anodic oxidation method according to the present invention uses sulfuric acid as an electrolyte, particularly as described in British Patent No. 1,412,
No. 768 or U.S. Pat. No. 4,211. A method of anodizing under conditions such as those described in No. 619 is preferred.

The amount of anodic oxide film is 0. The range is preferably 1-10 g/m', more preferably 1-6 g/m'.

(Dye dyeing treatment) The surface provided with the anodic oxide film is subsequently dyed with a dye treatment.

Dye dyeing is a process in which an aluminum plate with an anodic oxide film is dyed in the desired color using a dye.
This includes a method of immersing an aluminum plate in an aqueous dye solution, or a method of immersing it and electrolyzing it. Any dye may be used as long as it can dye the anodic oxide film, but acid dyes, direct dyes, etc. are generally used.

The aqueous dye solution may contain additives to obtain uniform dyeing.

Dyeing treatment conditions vary depending on the desired degree of staining and cannot be specified, but when dyeing by dipping, the dye concentration is 0.1-10g/l, the temperature is 20-70℃, and the treatment time is 2 seconds to 2 minutes. It is desirable to process it.

In order for the aluminum plate dyed in this manner to have an antihalation effect, it is required that its light absorption wavelength range overlaps with the wavelength to which the photosensitive composition is actually sensitive. The wavelength to which the photosensitive composition is actually sensitive refers to the wavelength at which the absorption wavelength of the photosensitive composition and the wavelength of the light source match. When exposing a photosensitive layer used as
07 or 415ron is required. Further, the degree of staining is carried out such that the degree of increase in optical density due to staining is within the range of 0.05 to 0.25 in terms of reflected optical density. Of course, this value should be a value measured at 407 or 415 nm if exposure is performed using a metal halide lamp as described above.

Specific examples of dyes that absorb in this wavelength range include Almarite Yellow 3GL manufactured by Kaname Shokai, Basalox Yellow GLN manufactured by Kaname Shokai Co., Ltd., and Aluminum Yellow G3 manufactured by Sandoz Co., Ltd.
LWSC. I. Acid Yellow 23 (Tartrazine), C. I. Acid Yellow 25, C,
I. Acid Yellow 36, C. I, Acid Yellow 38, C. I. acid orange 10
SC. I. Acid Red 13, C, I. Direct Yellow 8, C. I, Direct Yellow 12, C. I. Direct Yellow 27 etc.

However, these dyes exhibit a yellow or orange color;
When dyed with these dyes, the non-image area turns yellow and plate inspection becomes poor. If you want to avoid this, you can dye it with gray or black dye, or mix dyes such as yellow, red, blue, etc. to absorb gray in the wavelength range mentioned above. As a non-image area, deterioration of plate inspection properties can be prevented. Specific examples of gray or black dyes include Aluminum Gray NL and Aluminum Black 2LW manufactured by Sandoz Co., Ltd., and Basalox Black WL manufactured by Kaname Shokin. Specific examples of dyes that can be colored black 7 or gray by mixing dyes include Sandoz's Sanodal Deep Black MLW, but there are also other dyes that can be mixed with commercially available red, blue, yellow, etc. dyes. May be used.

(Sealing treatment) The surface dyed in this manner is subjected to a sealing treatment.

Sealing treatment involves exposing an aluminum plate with a porous anodic oxide film to a steam atmosphere, immersing it in hot water,
This is a process in which the holes in a porous anodic oxide film are filled with metal, oxide, or hydroxide by electrolytic treatment in an electrolytic solution.

When sealing with steam, pressurized or normal pressure steam is used. When immersing in hot water, various additives having a sealing promoting effect can be added to the hot water. When the pores are sealed by electrolysis in an electrolytic solution, various oxoacids, their salts, or inorganic fine particles mixed therein are used as the electrolyte. Any method other than these may be used as long as it can seal the pores of the porous film.

Among these pore sealing methods, a particularly useful method is a method of sealing with steam. In this case, the purpose can be achieved either by using pressurized steam or by using steam at normal pressure.

When using steam at normal pressure, the processing conditions are a relative humidity of 70
% or more and a steam temperature of 95° C. or more for about 2 seconds to 2 minutes is appropriate.

Such a sealing treatment can prevent the dye from moving into the photosensitive layer (weeping) during coating and development of the photosensitive layer. Furthermore, it is also possible to prevent problems such as staining due to irreversible adsorption of components contained in the photosensitive layer, such as dyes and polymer binders, to the surface of the support over time. A photosensitive lithographic printing plate in which a photosensitive layer is provided on such a support has excellent storage stability (shelf life).

The aluminum plate that has been subjected to the sealing treatment as described above can be used as a support for a lithographic printing plate immediately as it is, for example, it can be used as a support for wipe-on, or it can be coated with a photosensitive layer suitable for lithographic printing. After the sealing treatment, treatments such as hydrophilic treatment and application of a hydrophilic undercoat layer may be performed alone or in combination.

(Hydrophilization treatment) As the hydrophilization treatment used in the present invention, US Pat.
, 714. No. 066 and U.S. Pat. No. 3,181.
Alkali metal silicates (e.g. sodium silicate aqueous solution) as disclosed in No. 461, or
Potassium fluorozirconate disclosed in Publication No. 6-2 2063, and U.S. Pat. No. 4,153,
461, the method of treating with polyvinylphosphonic acid as disclosed in 4,689,272, etc.
Known methods can be used. Such hydrophilic treatment is preferably performed when a photosensitive layer containing a diazo resin is provided.

(Hydrophilic Undercoat Layer) Preferred hydrophilic undercoat layers used in the present invention are disclosed in JP-A-60-149491 and JP-A-60-2-3.
Hydrophilic undercoat layers such as those described in JP-A No. 299-8, JP-A-62-19494, and JP-A-59-101651 are included.

This undercoat layer may be provided after the above-mentioned sealing treatment, or may be provided after the above-mentioned hydrophilic treatment is performed after the sealing treatment.

The support that has been anodized, dyed, and pore-sealed in this way has a higher antihalation effect than supports produced using conventional methods, and exhibits excellent tone reproducibility. It is extremely surprising that the print is resistant to staining.

The support produced by the production method of the present invention can be provided with a photosensitive layer exemplified below to form a photosensitive lithographic printing plate.

[I) Photosensitive layer consisting of diazo resin and binder: As a negative-acting photosensitive diazo compound, U.S. Pat.
Diphenylamine is a reaction product of a diazonium salt disclosed in the specifications of No. 63, 631 and No. 2, 667, 415 and an organic condensing agent containing a reactive carbonyl group such as an aldol or an acetal. -p-
Condensation product of diazonium salt and formaldehyde (
A so-called photosensitive diazo resin) is preferably used. Other useful condensed diazo compounds are listed in Japanese Patent Publication No. 49-48001;
It is disclosed in the respective publications such as No. 49-45322 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.

Phenol. Examples of reactants with functional hydroxyl groups include diphenolic acids such as hydroxybenzophenone, 4,4-bis(4'-hydroxyphenyl)pentanoic acid, resorcinol, or diresorcinol, which can be further substituted. It may have a group. Hydroxybenzophenone includes 2,4-dihydroybenzophenone, 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 penzophenone, or soluble salts thereof, such as ammonium and alkali metal salts.

Sulfonic acid group-containing compounds may generally be substituted with lower alkyl, nitro groups, halo groups, and/or another sulfonic acid group. Preferred examples of such compounds include benzenesulfonic acid, toluenesulfonic acid,
Naphthalene sulfonic acid, 2,5-dimethylbenzenesulfonic acid, sodium benzenesulfonate, naphthalene-
2-sulfonic acid, 1-naphthol-2 (or 4) monosulfonic acid, 2,4-dinitro-1-naphthol-7-sulfonic acid, 2-hydroxy-4-methoxybenzophenone-5-sulfone Lm-( p'-anilinophenylazo)
Examples include sodium benzenesulfonate, alizarin sulfonic acid, 0-toluidine-m-sulfonic acid and ethanesulfonic acid. Sulfuric esters of alcohols or aromatic hydroxy compounds and their salts are also useful. Such compounds are usually readily available as anionic surfactants.

Examples include lauryl sulfate, alkylaryl sulfate, p-7 nylphenyl sulfate,
-Ammonium or alkali metals such as phenylethyl sulfate and inoctylphenoxydiethoxyethyl sulfate are mentioned.

These substantially water-insoluble photosensitive diazo resins are 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, British Patent No. 1. 312. The diazo resins described in No. 925 are also preferred.

The most preferred diazo resin is 2-methoxy-4-condensate of p-diazodiphenylamine and formaldehyde.
Hydroxy-5-penzoylbenzene 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, amino,
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. Shellac described in British Patent No. 521, British Patent No. 1. No. 460.978 and U.S. Pat. Polymers containing hydroxyethyl acrylate units or hydroxyethyl methacrylate units as the main repeating unit as described in U.S. Pat. No. 3,751. The polyamide resin described in specification No. 257, British Patent No. 1,
074. 392 and polyvinyl acecool resins such as polyvinyl formal resins, polyvinyl butyral resins, linear polyurethane resins as described in U.S. Pat. No. 3,660,097, Phthalated resins of polyvinyl alcohol, epoxy resins condensed from bisphenol A and epichlorohydrin, polymers containing amine groups such as polyaminostyrene and polyalmylamino (meth)acrylate, cellulose acetate, cellulose alkyl ether, cellulose acetate phthalate, etc. Cellulose derivatives and the like are included.

The composition of diazo resin and binder may further include a p}I indicator as described in British Patent No. LO 41,463, US Patent No. 3. 236, 646
Additives such as phosphoric acid and dyes described in the specification can be added.

[■] Photosensitive layer comprising an O-quinonediazide compound: A particularly preferred O-quinonediazide compound is an O-naphthoquinonediazide compound, for example, as described in U.S. Pat. 766
．． No. 118, same No. 2. 767. No. 092, No. 2
+772+972, same No. 2, 859, 112
No. 2. 907, 665, same No. 3. 046
, No. 110, No. 3, 046, 111, No. 3
, 046, No. 115, No. 3. 046. 118
No. 3, 046, 119, No. 3. 046
, No. 120, No. 3. 046, No. 121, No. 3
, No. 046, 122, No. 3, 046, 123
No. 3, 061, 430, No. 3, 102
, No. 809, same No. 3. 106. No. 465, No. 3
, No. 635, 709, No. 3, 647, 443
It is written in numerous publications, including the specifications of each issue.
These can be suitably used. Among these, O-naphthoquinonediazide sulfonic acid esters of aromatic hydroxy compounds or O-naphthoquinonediazidecarboxylic acid esters of aromatic hydroxy compounds and O-naphthoquinonediazide carboxylic acid esters of aromatic amino compounds are particularly suitable.
-Naphthoquinonediazide sulfonic acid amide or O-naphthoquinonediazidecarboxylic acid amide is preferred, especially the esterification of O-naphthoquinonediazide sulfonic acid to the condensate of pyrogallol and acetone as described in U.S. Pat. No. 3,635,709. Reacted product, U.S. Patent No. 4. British Patent No. 1,494,043, which is obtained by subjecting a polyester having a hydroxy group at the end to an ester reaction with 0-naphthoquinonediazide sulfonic acid or 0-naphthoquinonediazidecarboxylic acid as described in the specification of No. 028,111. 0-naphthoquinonediazide sulfonic acid or ○-naphthoquinonediazidecarboxylic acid is ester-reacted with a homopolymer of p-hydroxystyrene or a copolymer of this with other copolymerizable monomers as described in the specification of the No. , as described in U.S. Pat. No. 3,759,711.
- A copolymer of aminostyrene and another copolymerizable monomer with 0-naphthoquinone diazide sulfonic acid or 0-
An amide reaction product of naphthoquinonediazidecarboxylic acid is very good.

Although these 0-quinonediazide compounds can be used alone, it is preferable to use them in combination with an alkali-soluble resin. Suitable alkali-soluble resins include novolak-type phenolic resins, and specifically include phenol formaldehyde resins, 0-cresol formaldehyde resins, m-cresol formaldehyde resins, and the like. Further, U.S. Pat. No. 4,123. As described in the specification of No. 279, condensation of phenol or cresol substituted with an alkyl group having 3 to 8 carbon atoms such as t-butylphenol formaldehyde resin and formaldehyde together with the above-mentioned phenol resin. It is even more preferable to use it in combination with The alkali-soluble resin is about 50 to about 85% by weight, more preferably 60 to 80% by weight, based on the total weight of the composition constituting the photosensitive layer.
can be included.

A photosensitive composition comprising an 0-quinonediazide compound includes
If necessary, further dyes and plasticizers, such as British Patent No. 1,
401,463, U.S. Pat. No. 1,039,475, and U.S. Pat. No. 3,969,118, additives such as components that provide printout performance can be added. .

[■] Photosensitive layer consisting of a photopolymerizable photosensitive composition containing a polymer having a carboxylic acid residue or carboxylic acid anhydride residue, an addition polymerizable unsaturated compound, and a photopolymerization initiator. In this case, it is preferable to anodize the surface of the support grained in a hydrochloric acid bath with phosphoric acid or a mixed acid of phosphoric acid and sulfuric acid.

Polymers with carboxylic acid residues or carboxylic acid anhydride residues after anodizing in a phosphoric acid bath and silicate treatment,
A layer of a photopolymerizable photosensitive composition containing an addition polymerizable unsaturated compound and a photopolymerization initiator is provided. The printing plate formed in this way has a good shelf life, and the surface of the exposed aluminum plate in the non-image area is resistant to staining with printing ink and has good hydrophilicity to quickly remove the stained ink. It has high adhesive strength with the photosensitive layer.

Polymers having carboxylic acid residues or carboxylic anhydride residues suitable for this purpose include the following [A] to [D].
A polymer having a structural unit selected from the following is preferred.

(In the formula, Rl and R4 represent a hydrogen atom or an alkyl group, R3 is a phenylene group or an alkylene group that may have a hydroxy group, R' is a hydrogen atom, an alkyl group that may have a substituent, R6 represents an alkyl group, an allyl group, an aryl group, or a cycloalkyl group that may have a substituent, and n represents 0 or 1.)
More specific structural units include acrylic acid, methacrylic b, crotonic acid, vinylbenzoic acid, etc. as the formula (.), and maleic acid, monohydroxyalkylestenopemalein as the formula (B). Examples of the formula (C) include maleic acid monoalkylamide and maleic acid monohydroxyalkylamide, and examples of the formula (D) include maleic anhydride and itaconic anhydride. As the polymer, one having an average molecular weight of 1,000 to 10,000 is usually used.

The addition-polymerizable unsaturated compound has an ethylenically unsaturated double bond that mutually undergoes addition polymerization in a three-dimensional direction to cause insolubilization when the photopolymerizable photosensitive resin composition is irradiated with actinic rays. It is a monomer. Examples include unsaturated carboxylic acids, esters of unsaturated carboxylic acids and aliphatic polyhydroxy compounds, and esters of unsaturated carboxylic acids and aromatic polyhydroxy compounds.

As the photopolymerization initiator, benzoin, penzoin alkylethenopebenzophenone, anthraquinone, Michler's ketone, etc. can be used alone or in combination. This photosensitive composition has a coating weight of 1 to 3 g/m after drying.
It is preferable to apply it so that it becomes '.

[■] Electrophotographic photosensitive layer The electrophotographic photosensitive layer mainly consists of a photoconductive compound and a binder, but if necessary, known pigments may be added for the purpose of improving sensitivity and obtaining a desired photosensitive wavelength range. , dyes, chemical sensitizers, other additives, etc. can be used.

The photosensitive layer can be composed of a single layer or a plurality of layers in which charge generation and charge transport functions are separated. A lithographic printing plate can be obtained by forming a toner image on a photosensitive layer by a known electrophotographic process, and using this as a resist layer, non-image areas are decoated. For example, Special Publication No. 37-17162, No. 38-6961,
JP 56-107246, JP 60-254142, JP 59-36259, JP 59-25217,
JP 56-146145, JP 62-194257, JP 57-147656, JP 58-100862,
It is described in numerous publications including No. 57-161863, and any of these can be suitably used.

The thickness of the photosensitive layer is 0. A suitable thickness is 1-30 μm, more preferably 0.5-10 μm.

The photosensitive composition as described above is usually applied as a solution of water, an organic solvent, or a mixture thereof onto the support according to the present invention, and dried to prepare a photosensitive lithographic printing plate.

The photosensitive lithographic printing plate thus obtained is imagewise exposed to light using a light source containing actinic rays such as a carbon arc lamp, xenon lamp, mercury lamp, tungsten lamp, metal halide lamp, etc., and developed to obtain a lithographic printing plate.

(Effect of the invention) The lithographic printing plate obtained by exposing and developing the photosensitive lithographic printing plate using the support obtained by the method of the present invention has excellent tone reproducibility in both negative and positive types. has
There is no contamination of non-image areas, and it is easy to distinguish between image areas and non-image areas during the correction process, and there are no correction marks, so there is no staining of printed matter due to correction marks, and no scratches in non-image areas. Excellent hardness and wear resistance. Moreover, it has high printing durability. Furthermore, it has excellent ink stain recovery ability.

Furthermore, since no photosensitive layer remains after development, it has features such as easy water-ink balance.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples. In addition, (%) in the examples is (weight%) unless otherwise specified.
shall be.

Examples 1, 2, 3 The surface of JISA 1050 aluminum sheets was grained with a rotating nylon brush using a vamisu water suspension as an abrasive. The surface roughness (center line average roughness) at this time is 0.
It was 5μ. After washing with water, add 70% lO% caustic soda aqueous solution.
It was etched by immersing it in a solution heated to 0.degree. C. so that the amount of aluminum dissolved was 6 g/m'. After washing with water, 30
% nitric acid aqueous solution for 1 minute to neutralize it, and thoroughly washed with water.

Thereafter, in a 0.7% nitric acid aqueous solution, using a rectangular alternating waveform voltage with an anode voltage of 13 volts and a cathode voltage of 6 volts (power supply waveform described in the example of JP-A-52-77702). Perform electrolytic surface roughening for 20 seconds, 20%
The surface was cleaned by immersing it in a 50°C solution of sulfuric acid, and then washed with water.

Furthermore, a porous anodic oxide film formation treatment was performed using direct current in a 20% sulfuric acid aqueous solution. Electrolysis was carried out at a current density of 2 A/dm', and the electrolysis time was adjusted to adjust the weight of the anodic oxide film to 4.
A substrate of 0 g/m' was made.

Thereafter, 0.0% of tartrazine dye (c, I. acid yellow 23) having an absorption peak around 400 nm was added.
The anodized substrate was immersed in a 1% aqueous solution at 30° C., and then washed with water. By changing the dipping time, three types of substrates with different degrees of dyeing were created.

This substrate was processed for 30 seconds in a saturated steam chamber at 100° C. and 1 atm to prepare a support. These supports had a pale yellow color.

After that, add 2.5% No. 3 sodium silicate to a 70℃ aqueous solution for 30 minutes.
After dipping for a second, washing with water and drying, the degree of dyeing was measured, and a photosensitive solution having the following composition was applied and dried to form a photosensitive layer. The dry coating weight of the photosensitive layer was 2.0 g/m'.

Phosphorous acid-0. 0 5 g 2-methoxyethanol -1 0 0
g The photosensitive lithographic printing plate produced in this way was placed in a vacuum printing frame using Fuji Film Step Guide and Fogura Co., Ltd.
After exposure was carried out for 50 seconds using a 3 kW metal halide lamp from a distance of 1 m through a K-value film manufactured by FOGRA Co., Ltd., the plate was developed with a developer having the composition shown below, and gummed with an aqueous gum arabic solution to prepare a lithographic printing plate.

Developer solution Sodium sulfite Dg Benzyl alcohol 30g Sodium carbonate
・-5g pure water 10
00g Print stains in non-image areas and reproducibility of halftone dots were examined.

The results are shown in Table 1.

(Examples 4, 5, 6) Supports were created in the same manner as in Examples 1, 2, and 3. However, the dye staining treatment was performed using a 0.1% aqueous solution of Aluminum Yellow G3LW manufactured by Sandoz (Example 4), Basalox Yellow GLN manufactured by Kaname Shokai (Example 5), or Aluminum Gray NL manufactured by Sandoz (Example 6). (30℃
) was used.

Support dyed with aluminum gray NL (
Example 6) had a gray tone compared to before dyeing.

Thereafter, after measuring the degree of dyeing, silicate treatment, coating of a photosensitive layer, exposure and development, and gumming were performed in the same manner as in Examples 112 and 3 to prepare a lithographic printing plate.

As in Examples 1, 2, and 3, printing stains in non-image areas and reproducibility of halftone dots were examined. The results are shown in Table 1.

(Comparative Examples 1, 2, 3) A support was prepared in the same manner as in Examples 1, 2, and 3, but without dyeing or sealing, and the degree of dyeing was measured. Silicate treatment in the same manner as 2 and 3,
A lithographic printing plate was prepared by applying a photosensitive layer, exposing and developing, and gumming.

As in Examples 1, 2, and 3, printing stains in non-image areas and reproducibility of halftone dots were examined. The results are shown in Table 1.

(Comparative Example 4) After anodizing in the same manner as in Examples 1, 2, and 3, the
A support was prepared by dipping for 0 seconds. Thereafter, a 1% aqueous solution of cationic dye (c.I.BY-14) was applied and dried, and the degree of dyeing was measured. Next, in the same manner as in Examples 1, 2, and 3, photosensitive layer coating, exposure, development, and gumming were performed to prepare a lithographic printing plate.

As in Examples 1, 2, and 3, printing stains in non-image areas and reproducibility of halftone dots were examined. The results are shown in Table 1.

(Comparative Example 5) After dyeing in the same manner as in Examples 1, 2, and 3, the degree of dyeing was measured. Next: A lithographic printing plate was prepared by applying a photosensitive layer, exposing, developing and gumming in the same manner as in Examples 1, 2 and 3. As in Examples 1, 2, and 3, printing stains in non-image areas and reproducibility of halftone dots were examined. The results are shown in Table 1.

(Examples 7 and 8) The same method as in Examples 1, 2, and 3 was performed up to the step of forming a porous anodic oxide film.

Thereafter, 0.0% of Aluminum Yellow G3LW (Example 7) and Aluminum Gray NL (Example 8) manufactured by Sandoz.
The anodized substrate was immersed in a 1% aqueous solution at 30° C. for 20 seconds and washed with water. This substrate was treated for 30 seconds in a saturated steam chamber at 100° C. and 1 atm to prepare a support. Thereafter, the degree of dyeing was measured, and a photosensitive solution having the following composition was applied and dried to form a photosensitive layer. The dry coating weight of the photosensitive layer was 2.5 g/m'.

Methyl cellosolve 27 layers 1 part The photosensitive lithographic printing plate thus prepared was placed in a vacuum baking frame using Fujifilm Step Guide and FOGRA Co., Ltd. (FOGRA).
After exposure for 50 seconds using a 3km metal halide lamp from a distance of 1m,
25°C, 45% by 4% sodium metasilicate aqueous solution
It was developed for seconds and gummed with an aqueous gum arabic solution to prepare a lithographic printing plate.

The reproducibility of halftone dots was investigated and the results are shown in Table 2.

(Comparative Example 6) A support was prepared in the same manner as in Examples 7 and 8, but without dyeing and sealing, and after measuring the degree of dyeing, the same method as in Examples 7 and 8 was carried out. A photosensitive layer was applied, exposed, developed, and gummed to prepare a lithographic printing plate.

The reproducibility of halftone dots was investigated in the same manner as in Examples 7 and 8, and the results are shown in Table 2.
It was shown to.

From the above results, the lithographic printing plate obtained by exposing and developing the photosensitive lithographic printing plate using the support obtained according to method j of the present invention has no printing stains in the non-image area and has no halftone dots. It can be seen that it has excellent reproducibility and has superior characteristics compared to lithographic printing plates obtained by conventional methods that do not dye, or are dyed but do not seal.

Table 2 Performance of positive lithographic printing plates (Note 5) When printing with Fogra's K value film,
The minimum width of a thin line that can be printed on a printed matter without skipping.

The larger the value, the better the reproducibility of halftone dots.

Procedural amendment 1. Case Description 1990 Patent Application No. 7525 4. Agent 5. Date of amendment order Voluntary6. Column 7 for detailed description of the invention in the specification to be amended. Contents of the amendment (1) Insert "Light Yellow A, manufactured by Nippon Kayaku Co., Ltd." after "Minium Yellow G3LW," on page 10, line 15 of the specification.

(2) In the same book, page 18, line 9, "metal" is corrected to "metal salt."

(3) In the same book, page 20, line 7, "polyalmyl" is corrected to "polyalkyl."

(4) In the same book, page 22, line 9, ``Iruuna'' is corrected to ``Iru-una''.

(5) "85 weight" on page 23, line 8 of the same book is corrected to "85% by weight."

(6) "Bezofuryl" on page 35, line 11 of the same book is corrected to "1 benzofuryl."

(7) "3km" in the 4th line from the bottom of page 35 of the same book r 3
KW,” he corrected.

(8) “The larger the value” in the first line from the bottom of page 38 of the same book
is corrected to ``the smaller the value,'' the lower the value.

Claims (3)

[Claims] (1) A method for producing a support for a lithographic printing plate, which comprises roughening and anodizing the surface of an aluminum plate, and then subjecting it to (a) dye staining treatment and (b) pore sealing treatment in this order. (2) For a lithographic printing plate characterized in that the surface of an aluminum plate is roughened and anodized and then subjected to (a) dye staining treatment, (b) pore sealing treatment, and (c) hydrophilic treatment in this order. Method of manufacturing support. (3) The manufacturing method according to claim (1) or (2), wherein the dye staining process is performed using a dye that can produce a gray non-image area.