JPH07113777B2 - Developer and developing method for photosensitive lithographic printing plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a developing solution and a developing method for a photosensitive lithographic printing plate, and particularly to a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate. The present invention relates to a developing solution and a developing method capable of commonly developing a plate well.

[Prior Art] Conventionally, a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate have different compositions of developing solutions, and it has been possible to suitably develop only with each developing solution. Even if it was possible to develop using a developer that is not a dedicated developer, a lithographic printing plate with sufficient performance could not be obtained, and a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate had the same prescription phenomenon. Under the present circumstances, it is practically impossible to perform a common treatment with a liquid.

JP-A-60-64351 describes a common developing method in which a negative type photosensitive lithographic printing plate and a positive type photosensitive lithographic printing plate are both developed and processed by one automatic developing machine. However, this technology puts each dedicated developer in a separate developing bath,
The development for a negative photosensitive lithographic printing plate and the development for a positive photosensitive lithographic printing plate are carried out successively, and they are not developed with a developing solution of the same formulation.

Therefore, since each dedicated developing solution is used, solution management is troublesome, and it is difficult to carry out stable development for a long time.

On the other hand, a technique for performing common development with one developing solution is disclosed in JP-A-60
-130741. This developing solution comprises an organic solvent of ethylene glycol monophenyl ether or ethylene glycol monobenzyl ether, a silicate, an alkali metal hydroxide, an anionic surfactant and a tetraborate. However, when commonly developed with such a developing solution, ink stains may occur during printing on a negative photosensitive lithographic printing plate. Further, in the positive-working photosensitive lithographic printing plate, the development result was very likely to fluctuate, and a part of the image area was easily attacked and lost during development. This tendency is more noticeable when the development time is slightly extended or when the development temperature is slightly higher than the predetermined temperature, and as a result, the image details are lost or when printing is performed. This may cause poor printing durability.

The inventors of the present invention have previously been able to perform common development by the technique described in Japanese Patent Application No. 60-166250, but the phenomenon that the image part of the positive-working photosensitive lithographic printing plate as described above is likely to deteriorate is sufficiently caused. Was not resolved.

[Object of the Invention]

An object of the present invention is to provide an excellent developing solution and a developing method capable of favorably developing a negative type and a positive type photosensitive lithographic printing plate with one developing solution.

Another object of the present invention is to provide a developing solution and a developing method which have excellent development stability and a wide processing latitude.

Another object of the present invention is to provide a developing solution and a developing method capable of obtaining a plate having excellent printing performance.

Another object of the present invention is to provide an excellent developing solution and a developing method capable of rapidly developing negative-type and positive-type photosensitive lithographic printing plates.

[Structure of Invention]

As a result of intensive studies, the present inventors have shown that when a negative photosensitive lithographic printing plate having an image forming layer on an aluminum support and a positive photosensitive lithographic printing plate are commonly treated with an aqueous alkaline developer. , 0.1 to 10% by weight of an organic solvent whose solubility in water at 20 ° C is 10% by weight or less,
The above object of the present invention can be achieved by containing 0.001 to 10% by weight of a cationic surfactant, a sulfite and an anionic surfactant, and adjusting the pH to a range of 11.5 to 13.5.

The developer in the present invention has a solubility in water at 20 ° C. of 10 to 10% by weight of an organic solvent of 10% by weight or less, 0.001 to 10% by weight of a cationic surfactant, a sulfite, an anionic surfactant, and an alkali. Contains agent and pH is 11.5
It is an alkaline developer whose main solvent is water in the range of 13.5. Here, "mainly composed of water" means that at least 50% by weight of the solvent of the developer is water.

Various types of cationic surfactants can be used in the present invention. Cationic surfactants are roughly classified into amine type and quaternary ammonium salt type, and any of these can be used in the present invention.

Examples of amine type include polyoxyethylene alkyl amine, N-alkyl propylene amine, N-alkyl polyethylene polyamine, N-alkyl polyethylene polyamine dimethyl sulfate, alkyl biguanide, long chain amine oxide, alkyl imidazoline, 1-hydroxyethyl- 2-alkylimidazoline, 1-acetylaminoethyl-2-alkylimidazoline, 2-alkyl-4
-Methyl-4-hydroxymethyloxazoline and the like.

Examples of the quaternary ammonium salt type include long-chain primary amine salt, alkyl trimethyl ammonium salt, dialkyl dimethyl ethyl ammonium salt, alkyl dimethyl ammonium salt, alkyl dimethyl benzyl ammonium salt, alkyl pyridinium salt, alkyl quinolinium salt. , Alkylisoquinolinium salt, alkylpyridinium sulfate, stearamidomethylpyridinium salt, acylaminoethyldiethylamine salt, acylaminoethylmethyldiethylammonium salt, alkylamidopropyldimethylbenzylammonium salt, fatty acid polyethylene polyamide, acylaminoethylpyridinium salt , Acylcholaminoformylmethylpyridinium salt, stearooxymethylpyridinium salt, fatty acid triethanolamine, fatty acid trieta Ruamingi salt, trioxyethylene fatty acid triethanolamine, fatty acid dibutylaminoethanol, cetyl oxymethyl pyridinium salt,
p-isooctylphenoxyethoxyethyl dimethylbenzyl ammonium salt and the like. (The "alkyl" in the examples of the above compounds represents a straight chain or partially substituted alkyl having 6 to 20 carbon atoms, and specifically, a straight chain alkyl such as hexyl, octyl, cetyl, stearyl, etc. Among these, water-soluble quaternary ammonium salt-type cationion type surfactants are particularly effective, and among them, alkyl trimethyl ammonium salt, alkyl dimethyl benzyl ammonium salt, ethylene oxide addition ammonium salt and the like are preferable. Is. A polymer having a cation component as a repeating unit is also a cationic surfactant in a broad sense, and is included in the cationic surfactant of the present invention. In particular, a polymer containing a quaternary ammonium salt obtained by copolymerizing with a lipophilic monomer can be preferably used.

The addition amount of the above-mentioned cationic surfactant is in the range of 0.001 to 10% by weight, more preferably 0.01 to 1% by weight. If the addition amount is less than 0.001% by weight, the effect of the present invention is weak, and if it exceeds 10% by weight, development is suppressed and good performance cannot be obtained. The weight average molecular weight is 300 to 50,
It is in the range of 000, particularly preferably in the range of 500 to 5,000. These cationic surfactants may be used alone or in combination of two or more.

The developer according to the present invention has a negative photosensitive lithographic printing plate having a solubility in water at 20 ° C. of 10% by weight or less of an organic solvent, a cationic surfactant, a sulfite and an anionic surfactant. The development balance of positive-working photosensitive lithographic printing plates can be balanced, development can be performed more quickly, and photosensitive lithographic printing plates of a wider range of products that have large differences in developability, etc. can be processed with a common developer. To enable that.

First, as a preferable additive, an organic solvent having a solubility in water at 20 ° C. of 10% by weight or less can be mentioned. By including this additive, the above effect can be enhanced.

Examples of the organic solvent having a solubility in water at 20 ° C. of 10% by weight or less used in the present invention include ethyl acetate, propyl acetate, butyl acetate, amyl acetate, benzyl acetate, ethylene glycol monobutyl acetate, butyl lactate, and butyl levulinate. Carboxylic acid esters such as; ethyl butyl ketone, methyl isobutyl ketone, ketones such as cyclohexanone; ethylene glycol monobutyl ether, ethylene glycol benzyl ether, ethylene glycol monophenyl ether, benzyl alcohol, methylphenyl carbinol, n-amyl alcohol, Alcohols such as methylamyl alcohol; alkyl-substituted aromatic hydrocarbons such as xylene; halogens such as methylene dichloride, ethylene dichloride, monochlorobenzene. And hydrocarbons. One or more of these organic solvents may be used. Among these organic solvents, ethylene glycol monophenyl ether, ethylene glycol benzyl ether and benzyl alcohol are particularly preferable.

The organic solvent is an excellent additive for improving the developability for both negative type and positive type plates, but at the same time, it deteriorates the film in the image area for positive type photosensitive lithographic printing plates. It also has the drawback of softening the image. Since the positive-working photosensitive lithographic printing plate does not undergo a crosslinking reaction during exposure, unlike the negative-working photosensitive lithographic printing plate, it is largely deteriorated when the development is excessive, and further deteriorated in the presence of an organic solvent. Grows larger. As a result of intensive studies, the inventors of the present invention described above, in order to prevent the deterioration of the positive photosensitive lithographic printing plate during development and to develop the negative photosensitive lithographic printing plate well, in a developing solution. 0.000 cationic surfactant
It has been found that the content is in the range of 1 to 10% by weight.

In particular, the cationic surfactant has a solubility in water of 10
In the presence of an organic solvent in an amount of not more than 10% by weight, the function of preventing film deterioration and image softening of the positive-working photosensitive lithographic printing plate is remarkable, and there is almost no adverse effect on the negative-working photosensitive lithographic printing plate, and both plates are It shows an excellent effect when developing in common.

Although the pH of the developer according to the present invention is in the range of 11.5 to 13.5, when a negative photosensitive lithographic printing plate is developed at such a high pH, stains are generated during printing while being developed in a certain type of plate. Sometimes. The degree of the stain depends on the pH, and the higher the pH, the easier the stain becomes. Such high pH
Sulfite is very effective in developing the negative photosensitive lithographic printing plate well (pH 11.5 or more) and eliminating stains during printing, and the anionic surfactant is the negative photosensitive It shows a great effect in promoting the development of the lithographic printing plate.

Sulfite has a function of dissolving a water-insoluble diazo resin in an aqueous solution, and particularly in the development of a lithographic printing plate composed of a photosensitive layer combined with a hydrophobic resin, there is no stain even on a plate material that has been aged for a long time after production. You can make printing plates. Further, it improves the developability particularly when the negative photosensitive lithographic printing plate is developed at high pH. As sulfite, sodium, potassium,
Alkali metals such as lithium and alkaline earth metal salts such as magnesium or ammonium salts are useful.

The concentration of sulfurous acid is preferably 0.1 to 10% by weight, particularly preferably 0.2 to 5% by weight.

As the anionic surfactant, higher alcohols (C ₈ ~
C ₂₂ ) Sulfate salts [for example, sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, "Tayball B-81" (trade name, manufactured by Ciel Chemical Co.), second sodium alkyl Sulfate, etc.], aliphatic alcohol phosphate salts (eg, sodium salt of cetyl alcohol phosphate ester), alkylaryl sulfonates (eg, sodium salt of dodecylbenzene sulfonate, sodium salt of isopropylnaphthalene sulfonate, dinaphthalene) Sodium salt of disulfonic acid, sodium salt of metanitrobenzene sulfonic acid, etc., Sulfonates of alkylamide (eg, ), Dibasic fatty acid ester sulfonates (eg, sodium sulfosuccinate dioctyl ester,
Sodium sulfosuccinate dihexyl ester). Of these, alkylnaphthalene sulfonates are particularly preferably used.

The concentration of the anionic surfactant is 0.2 to 10% by weight, especially 1 to
A range of 5 weights is preferred.

As the alkaline agent used in the developer of the present invention, sodium silicate, potassium silicate, sodium hydroxide, lithium hydroxide, sodium triphosphate, dibasic sodium phosphate, tribasic potassium phosphate, dibasic potassium phosphate, Inorganic alkaline agents such as tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, sodium carbonate, potassium carbonate, ammonium carbonate, mono-, di- or triethanolamine and tetraalkylammonium hydroxide Such organic alkali agents and organic ammonium silicates are useful. Of these, alkali silicates are most preferable because they are stable in development. The content of the alkaline agent in the developer composition is preferably used in the range of 0.05 to 20% by weight, more preferably 0.
It is 1 to 10% by weight.

The most preferred embodiment of the present invention is an embodiment in which the developer satisfies the above conditions and contains a silicate as an alkaline agent. According to this embodiment, various kinds of photosensitive lithographic printing plates having different developing properties can be developed better and more quickly with one developing solution.

The following additives may be added to the developer according to the present invention in order to further improve the developing performance. For example, neutral salts such as NaCl, KCl, and KBr described in JP-A-58-75152, JP-A-58-75152
-190952, EDTA, NTA and other chelating agents, JP-A-59-1
Complexes such as [Co (NH ₃ ) ₆ ] Cl ₃ described in 21336, JP-A-50-513
Sodium alkylnaphthalene sulfonate described in No. 24,
Anionic or amphoteric surfactants such as N-tetradecyl-N, N-dihydroxyethylbetaine, JP-A-56-142528
Such as a copolymer of vinylbenzyltrimethylammonium chloride and sodium acrylate described in JP-A No. 57-192952, a reducing inorganic salt described in JP-A No. 58-59444, lithium chloride, etc. Inorganic lithium compounds, organic lithium compounds such as lithium benzoate described in JP-B-50-34442, organometallic surfactants containing Si, Ti, etc. described in JP-A-59-75255, JP-A-59-84241 Examples of the organic boron compound include

The image forming layer of the photosensitive lithographic printing plate according to the present invention contains a photosensitive substance as an essential component, and its physical and chemical properties are changed by exposure or subsequent development as a photosensitive substance, For example, one that causes a difference in solubility in a developer due to exposure, one that causes a difference in intermolecular adhesion before and after exposure, one that causes a difference in affinity for water and oil due to exposure or subsequent development processing, and an electron. A device capable of forming an image portion by a photographic method, and JP-A-55
The multi-layered structure described in No. 166645 can be used.

Typical examples of the photosensitive substance are, for example, a photosensitive diazo compound, a photosensitive azide compound, a compound having an ethylenically unsaturated double bond, an epoxy compound which causes polymerization with an acid catalyst, and a C—O— compound which decomposes with an acid. Examples thereof include compounds having a C-group, silyl ether or silyl ester. Typical o-quinone diazide compounds, acid-decomposable ether compounds and ester compounds, which change into alkali solubility upon exposure, are mentioned. Aromatic diazonium salts and the like are mentioned as negative type compounds whose solubility is reduced by exposure.

Specific examples of the o-quinonediazide compound include, for example, JP-A-47-5303, JP-A-48-63802, JP-A-48-63803, and JP-A-49-38.
No. 701, No. 56-1044, No. 56-1045, Japanese Patent Publication No. 41-11222
No. 43-28403, No. 45-9610, No. 49-17481, U.S. Patent Nos. 2,797,213, 3,046,120, 3,188,210, and
3,454,400, 3,544,323, 3,573,917, 3,67
4,495, 3,785,825, British Patents 1,227,602, 1,2
51,345, 1,267,005, 1,329,888, 1,330,93
2, German Patent 854,890, JP-A-60-37549, 60-1
Nos. 0247 and 60-3625 can be mentioned, and at least the present invention is preferably applied to a photosensitive lithographic printing plate using these compounds alone or in combination as a photosensitive component. You can

These photosensitive components include o-quinone diazide sulfonic acid ester of aromatic hydroxy compound or o-quinone diazide carboxylic acid ester and o of aromatic amino compound.
-Quinone diazide sulfonic acid or o-quinone diazide carboxylic acid amide, and those in which these o-quinone diazide compounds are used alone, and those in which the mixture is provided as a photosensitive layer by mixing with an alkali-soluble resin are also included. .

The alkali-soluble resin includes novolac type phenol resin, and specifically includes phenol formaldehyde resin, cresol formaldehyde resin, phenol cresol mixed formaldehyde resin, cresol xylenol mixed formaldehyde resin and the like. Further, as described in JP-A No. 50-125806, phenol or cresol and formaldehyde substituted with an alkyl group having 3 to 8 carbon atoms such as t-butylphenolformaldehyde resin together with the above-mentioned phenol resin are used. What used together with the condensate of and is also applicable. If necessary, the photosensitive layer containing the o-quinonediazide compound as a photosensitive component may further contain additives such as a dye, a plasticizer, and a component that imparts printout performance.

The present invention can be applied to the case where the amount of the photosensitive layer containing the o-quinonediazide compound as a photosensitive component per unit area is preferably about 0.5 to 7 g / m ² .

The image exposure of the positive-working photosensitive lithographic printing plate to which the method of the present invention is applied does not have to be particularly changed and may be carried out by a conventional method.

A typical photosensitive component of the negative type photosensitive layer is a diazo compound, for example, a diazo resin which is a condensate of a diazonium salt and / or p-diazophenylamine and formaldehyde, as described in JP-B-52-7364. P-diazophenylamine phenol salt or fluorocaprate, etc., such as a copolycondensate of 3-methoxydiphenylamine-4-diazonium chloride, 4-nitrodiphenylamine and formaldehyde described in JP-B-49-48001. Diazo resin consisting of organic solvent soluble salt, p
2-methoxy-4-hydroxy-5-benzoylbenzenesulfonate of a condensate of diazodiphenylamine and formaldehyde, tetrafluoroborate, hexafluorophosphate of a condensate of p-diazophenylamine and formaldehyde, etc. Is mentioned. At least the present invention can be preferably applied to a negative photosensitive lithographic printing plate containing these as a photosensitive component.

The present invention can be applied not only to these diazo compounds used alone, but also to those used by mixing with various resins in order to improve the physical properties of the photosensitive layer. Examples of such resins include shellac, polyvinyl alcohol derivatives, copolymers having an alcoholic hydroxyl group in the side chain described in JP-A-50-118802, and JP-A-55-155355. Examples thereof include copolymers having a phenolic hydroxyl group as a side chain.

These resins are copolymers containing at least 50% by weight of the structural unit represented by the following general formula, (In the formula, R ₁ represents a hydrogen atom or a methyl group, R ₂ represents a hydrogen atom, a methyl group, an ethyl group or a chloromethyl group, and n is an integer of 1 to 10) and an aromatic hydroxyl group. A polymer compound having 1 to 80 mol% of monomer units and 5 to 90 mol% of acrylic acid ester and / or methacrylic acid ester monomer units and having an acid value of 10 to 200 is included.

To the photosensitive layer of the negative photosensitive lithographic printing plate to which the developing solution and the developing method of the present invention are applied, an additive such as a dye, a plasticizer and a component which gives printout performance can be further added.

The amount per unit area of the photosensitive layer is at least 0.1 to 7 g / m ²
The present invention can be applied to the range of.

An aluminum support (including an aluminum-coated composite support) is used as the support used in the photosensitive lithographic printing plate.

Further, the surface of the aluminum material is preferably roughened for the purpose of increasing water retention and improving adhesion to the photosensitive layer.

Examples of the roughening method include generally known brush polishing method, ball polishing method, electrolytic etching, chemical etching, liquid honing, sand blasting and the like and combinations thereof, preferably brush polishing method, electrolytic etching, chemical method. Etching and liquid honing, of which the roughening method involving the use of electrolytic etching is particularly preferred. Further, as the electrolytic bath used in the electrolytic etching, an aqueous solution containing an acid, an alkali or a salt thereof or an aqueous solution containing an organic solvent is used, and among these, an electrolytic solution containing hydrochloric acid, nitric acid or a salt thereof is particularly used. Liquids are preferred. Further, the surface-roughened aluminum plate is desmutted with an acid or alkali aqueous solution, if necessary.

The aluminum plate thus obtained is preferably anodized, and particularly preferably, a method of treating with a bath containing sulfuric acid or phosphoric acid can be mentioned. Further, surface treatment such as sealing treatment and immersion in an aqueous solution of potassium fluorozirconate may be carried out, if necessary.

Further, the development processing method using the developing solution according to the present invention includes, in addition to the development processing step, if necessary, after the development processing step, a development stop processing step (the stop processing solution includes a disposable system and a recycling system) Each of the individual processing steps, the development stop processing step and the desensitization processing step succeeding to it, the processing step combining the development processing step and the desensitization processing, or the development stop processing step and the desensitization processing step. For example, a combination of the treatment steps disclosed in JP-A-54-8001 may be included.

When the negative-type and positive-type photosensitive lithographic printing plates according to the present invention are commonly developed with the same developer, the conditions other than the developer composition (for example, developing temperature, developing time, etc.) are the same. It is optional to change it.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to specific examples, but the present invention is not limited thereto.

Examples 1 to 7 and Comparative Examples 1 to 2 An aluminum plate having a thickness of 0.24 mm was immersed in a 20% sodium phosphate aqueous solution for degreasing, and this was electrolytically polished in a 0.2 N hydrochloric acid bath at a current density of 3 A / m ^2. After that, it was anodized in a sulfuric acid bath. At this time, the amount of anodic oxidation was 4 g / m ² . Further, sealing treatment was performed with an aqueous solution of sodium metasilicate to prepare an aluminum plate used for a lithographic printing plate. Next, the following photosensitive liquid A was applied onto this aluminum plate to form a negative photosensitive lithographic printing plate, and photosensitive liquid B was applied to obtain a positive photosensitive lithographic printing plate. The coating was performed with a spin coater and dried at 100 ° C. for 4 minutes. The coating film weight was 2.5 g / m ² for both plates.

(Photosensitive solution A) N- (4-hydroxyphenyl) methacrylamide:
Copolymer of acrylonitrile: ethyl acrylate: methacrylic acid = 27: 33: 41: 6 (weight ratio) (acid value 80) …… 5.
0g ・ Hexafluorophosphate of paraformaldehyde condensate of p-diazodiphenylamine …… 0.5g ・ Julimer AC-10L (trade name, manufactured by Nippon Pure Chemical Industries, Ltd., acrylic acid polymer) 0.05g ・ Tartaric acid …… 0.05g・ Victoria Pure Blue BOH (Brand name, Hodogaya Chemical Co., Ltd., dye) …… 0.1g ・ Novolak resin (pp-3121) (Gunei Chemical Co., Ltd.) …… 0.15g ・ Pluronic L-64 ( Product name, Asahi Denka Co., Ltd., surfactant) 0.005g Methyl cellosolve 100ml (photosensitive solution B) Naphthoquinone- (1,2) -diazide- (2) -5-sulfonic acid chloride Condensate with resorcin-benzaldehyde resin ...... 3.5g ・ m-cresol-formaldehyde novolak resin "MP-707" (Koriei Chemical Industry Co., Ltd.) ...... 9g ・ Naphthoquinone- (1,2) -diazide- ( 2) -4-sulfo Acid chloride …… 0.15g ・ Victoria Pureable-BOH (trade name, Hodogaya Chemical Co., Ltd., dye) …… 0.2g ・ Methylcellosolve …… 100g The plate thus obtained is a step wedge with a concentration difference of 0.15. Through a 2 Kw metal halide lamp. After that, using the developer of Table-1,
When the development processing was carried out while changing the development time at ° C, the results shown in Table 2 were obtained.

The pH of the developer should be 10% immediately before use, after adding additives.
It was adjusted with NaOH or IN-HCl.

In Table 2 and Table 3 below, N plate represents a negative photosensitive lithographic printing plate, P plate represents a positive photosensitive lithographic printing plate,
In addition, gradation is the development ink SPO-1 (Konishi Rokusha Kogyo Co., Ltd.)
Manufactured) and evaluated.

As can be seen from Table-2, the developing solutions of Examples 1 to 7 have a wider developing latitude than the developing solutions of Comparative Examples 1 to 4, and the gradation of the positive type lithographic printing plate has a high gradation (better step number and The difference in the number of clear stages was small.), Indicating excellent developing performance. Further, among the developers of Examples 1 to 7, those using the quaternary ammonium salt type cationic surfactant had a better development latitude and gradation than those using the amine type cationic surfactant. Showed sex.

Example 8 Ethylene glycol monomethyl ether 30 under nitrogen stream
0 parts by weight is heated to 100 ° C., into which 150 parts by weight of 2-hydroxyethyl methacrylate, 90 parts by weight of acrylonitrile, 79.5 parts by weight of methyl methacrylate, 1 part of methacrylic acid are added.
2 parts by weight of a mixture of 0.5 parts by weight and 1.2 parts by weight of benzoyl peroxide.
It dripped over time.

15 minutes after the completion of dropping, 300 parts by weight of ethylene glycol monomethyl ether and 0.3 parts by weight of benzoyl peroxide were added, and the reaction was continued for 4 hours. After completion of the reaction, the mixture was diluted with methanol and poured into water to precipitate the copolymer, which was dried under vacuum at 70 ° C.

The acid value of this 2-hydroxyethyl methacrylate copolymer (1) was 21.

A 0.15 mm-thick 2S aluminum plate was immersed in a 10% aqueous solution of sodium triphosphate held at 80 ° C for 3 minutes to degrease it,
After graining with a nylon brush, desmutting was performed with a 3% aqueous solution of sodium aluminate at 60 ° C. This aluminum plate is anodized in 20% sulfuric acid at a current density of 2 A / dm ² for 2 minutes,
Then, it was treated with a 25% aqueous solution of sodium silicate at 70 ° C. for 1 minute.

The following photosensitive solution was applied to this aluminum plate and dried at 100 ° C. for 2 minutes to obtain a negative photosensitive lithographic printing plate.

-2-hydroxyethyl methacrylate copolymer (1)
...... 87 parts by weight 2-methoxy-4-hydroxy-5-benzoylbenzenesulfonate of a condensate of p-diazodiphenylamine and paraformaldehyde ...... 10 parts by weight ・ Oil Blue # 603 (manufactured by Orient Chemical Industry Co., Ltd., Triphenylmethane oil-soluble dye) 3 parts by weight 2-Methoxyethanol 600 parts by weight Methanol 600 parts by weight Ethylene dichloride 600 parts by weight Dry coating weight was 2.5 g / m ² . . A step wedge and a negative original image with halftone dots were brought into close contact with this photosensitive lithographic printing plate, and image exposure was carried out for 40 seconds from a distance of 70 cm with a carbon arc lamp of 30 amperes.

On the other hand, as a positive photosensitive lithographic printing plate, U.S. Pat.
No. 9, 1 part by weight of naphthoquinone-1,2-diazide-5-sulfonic acid ester of polyhydroxyphenyl obtained by condensation polymerization of acetone and pyrogallol and 2 parts by weight of novolak type cresol formaldehyde resin. Part, 0.03 parts by weight of Oil Bull # 603 2
A photosensitive solution prepared by dissolving in 0 parts by weight of 2-methoxyethyl acetate and 20 parts by weight of methyl ethyl ketone was applied to an anodized aluminum plate after graining, dried at 80 ° C for 2 minutes and dried. A photosensitive lithographic printing plate of / m ² was obtained. A step wedge and a transparent positive original image with halftone dots were brought into close contact with this photosensitive lithographic printing plate, and image exposure was carried out for 60 seconds from a distance of 70 cm with a carbon amp lamp of 30 amperes.

As described above, the exposed negative-type and positive-type photosensitive lithographic printing plates were processed using the following developing solution [A] to prepare an automatic processor PSP-860.
(Konishi Roku Photo Industry Co., Ltd.).
The results are shown in Table-3.

The developing conditions are 25 ℃ and 30 ℃ for 30 seconds and 27 ℃ for 20 seconds and 40 seconds, respectively.
It was done at 4 points per second. The pH of the developer is NaOH when using.
I adjusted it to 12.60.

Developer [A] -Sodium silicate 250g (Japanese Industrial Standard Sodium Silicate No. 3) -Sodium hydroxide 30g-Ethylene glycol monophenyl ether 100g-Perex NB-L (Kao Atlas Co., Ltd. anionic surfactant) 1,714g-Sodium sulfite 200g-Sanisol C (Kao Atlas Co., Ltd. cationic surfactant, dodecylbenzyldimethylammonium chloride) 10g-Solfit (3-methyl-methoxybutanol) 20
0 g water 10 l As a comparative developer, a developer [B] obtained by removing the cationic surfactant "Sanisol C" from the above developer [A].
Was prepared. Further, a developer [C] was prepared by removing the cationic surfactant "Sanisol C" and sodium sulfite from the developer [A]. The pH of the developing solutions [B] and [C] was adjusted to 12.50 at the time of use.

As is clear from Table 3, the developer [A] of the present invention comprises
The optimum development point is 25 ° C for 30 seconds to 27 ° C for 20 seconds. Even if the time and temperature increase causes overdevelopment to some extent under these development conditions, there is no significant change in the development results, and 150 lines / ink dot Is an excellent developer that is well reproduced and has a wide development latitude. On the other hand, in the comparative developer [B] obtained by removing the cationic surfactant from the developer [A], the development suitable points are 25 ° C. for 30 seconds and 27 ° C. for 20 seconds. However, the image of the positive type lithographic printing plate was unfavorable because it had a soft tone (the difference between the number of clear steps and the number of solid steps was large). Further, when the temperature of the developing solution becomes a little high, or when the developing time becomes long and the developing becomes excessive, the performance is greatly deteriorated, and the image tends to have a softer tone. %, The small dots became thin or disappeared, and sufficient performance could not be obtained.

Also, with respect to the negative type lithographic printing plate, the developing solution [A] of the present invention was superior to the comparative developing solution [B] in the developing latitude, although the amount was small.

〔The invention's effect〕

According to the present invention, in the case of developing a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate with one developing solution (for example, a negative type and a positive type photosensitive lithographic plate with the same developing solution using an automatic developing machine). In the case of developing the printing plate indiscriminately), the developability, the printing performance and the developing speed are improved.

For rapid development, usually, there is a method in which the developer is thickened, the processing temperature is raised, or an additive having a development promoting effect such as an organic solvent is added. Conventionally, it was difficult to obtain a stable and good image with a narrow latitude. However, according to the present invention, a good image can be stably obtained even if the development is performed at a speed about twice as fast as the conventional one.

When an organic solvent having a solubility in water at 20 ° C of 10% by weight or less is used as a developing solution, the image area is often corroded during the development of a positive-working photosensitive lithographic printing plate, and even in a slight excess of development. Although the image may be lost or the film may be thin, according to the present invention, the addition of the cationic surfactant as described above,
Even in the presence of the above-mentioned organic solvent, common development can be performed well.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-130741 (JP, A) JP-A-60-213943 (JP, A) JP-A58-9143 (JP, A) JP-A-61- 18944 (JP, A)

Claims (4)

[Claims] 1. A water-based alkaline developer for commonly treating a negative photosensitive lithographic printing plate having an image forming layer on an aluminum support and a positive photosensitive lithographic printing plate, wherein the developer is water at 20 ° C. 0.1-10% by weight of organic solvent having a solubility of 10% by weight or less, and a cationic surfactant
A photosensitive lithographic printing plate developer containing 0.001 to 10% by weight of sulfite and an anionic surfactant and having a pH in the range of 11.5 to 13.5. 2. The developer according to claim 1, wherein the cationic surfactant is a water-soluble surfactant having a quaternary ammonium salt type structure. 3. A method of commonly treating a negative photosensitive lithographic printing plate and a positive photosensitive lithographic printing plate having an image forming layer on an aluminum support with an aqueous alkaline developing solution, wherein the developing solution is Solubility in water at 20 ℃
0.1 to 10% by weight of an organic solvent of 10% by weight or less, 0.001 to 10% by weight of a cationic surfactant, a sulfite and an anionic surfactant are contained, and the pH is in the range of 11.5 to 13.5. Method for developing a photosensitive lithographic printing plate. 4. The developing method according to claim 3, wherein the cationic surfactant is a water-soluble surfactant having a quaternary ammonium salt type structure.