JPH03191355A - Method of development processing for photosensitive planographic plate - Google Patents

Abstract

PURPOSE:To enhance developabiltiy and to prevent occurrence of sludge by incorporating a lithium salt in a developing solution and feeding the developing solution in an amount of 70-700 ml/m<2> of photosensitive planographic plate. CONSTITUTION:The developing solution contains the lithium salt selected from inorganic salts, such as chloride, bromide, or sulfate, and organic acid salts, such as stearate, oleate, or tartarate, in an amount of 0.01-5 wt.%, and it has a pH of 12-13.5 and a SiO2/M ratio of 0.05-0.5, M being alkali metals except lithium, and it is fed in an amount of 70-700 ml/m<2> of printing plate, thus permitting the obtained developing solution not to attack an aluminum substrate, to enhance developing performance, to prevent occurrence of sludge, and to raise its concentration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for developing a photosensitive lithographic printing plate. Specifically, the present invention relates to a method for developing a photosensitive lithographic printing plate. The present invention relates to a method for developing a photosensitive lithographic printing plate (hereinafter referred to as "28 plate" as necessary) that can prevent the generation of sludge and has excellent developer concentration properties.

(Prior Art) Conventionally, Japanese Patent Application Laid-Open No. 61 (1983) was developed as a 28-plate processing method that does not require developer management and can stably obtain high-quality lithographic printing plates.
As shown in Japanese Patent No. 243455 and No. 62-42159, a method is known in which a substantially unused developer is supplied to the surface of the 28 plate to be processed for development.

(Problem to be Solved by the Invention) In the conventional processing method, since substantially unused developer is used, the amount of developer used is reduced in order to prevent cost increase. In other words, a small amount of developer is It is necessary to supply it to the surface of the plate and develop it. In order to perform rapid processing using such a small amount of developer, it is necessary to increase the pH of the developer.

However, when a high pH developer is used, the back side of the aluminum plate, which is the support for the 28th plate being processed, is eroded by the developer and looks like a white powder (this is called discoloration on the back side of the support). There are problems such as the generated white powder adhering to other plates during plate making and the generation of dust damaging the work environment.

Further, there is a problem in that the aluminum component eluted into the developer combines with the silica component and potassium component contained in the developer, resulting in sludge.

As a means to solve such problems, it is known to increase the content of alkali metal silicate in the developer.

However, there are problems such as poor developability and poor concentration of the developer. There is also the problem that SjO, etc. are precipitated and clogging of the developer supply nozzle of an automatic processor is apt to occur. Furthermore, when additives such as surfactants are added to the developer, there is also the problem that their dissolution is hindered.

Therefore, an object of the present invention is to develop a photosensitive lithographic printing plate that prevents an aluminum support from being attacked by a developer, has excellent developability, prevents the generation of sludge, and has excellent developer concentration. Our goal is to provide the following.

[Means to solve the problem]

As a result of intensive studies to achieve the above object, the inventors have arrived at the present invention.

That is, in the method for developing a photosensitive lithographic printing plate according to the present invention, after imagewise exposing a photosensitive lithographic printing plate having a photosensitive layer on a support, a substantially unused alkaline developer containing water as a main solvent is used. In a method for developing a photosensitive lithographic printing plate, which comprises supplying and developing the lithographic printing plate to the surface of each photosensitive lithographic printing plate to be processed.

The developer solution contains (i) a lithium salt in an amount of 0.01 to 5'rfL, and (ii) a pl+ of 12 to 13.5.
and (iii) 0.05≦rsio*]/
[M] < 0.50 (provided that M is an alkali metal other than Li), and the amount of developer supplied is 70 to 700 ml per 1 m'' of the photosensitive planographic printing plate.

The present invention will be explained in detail below.

The developer used in the present invention is an alkaline developer that uses water as a main solvent and contains a lithium salt.

Examples of lithium salts used in the developer of the present invention include inorganic lithium salts such as lithium chloride, lithium bromide, lithium nitrate, lithium hydroxide, lithium carbonate, and lithium sulfate, lithium stearate, lithium oleate, and lithium lauryl sulfonate. , lithium organic fatty acids such as lithium oxalate, lithium citrate, lithium maleate, lithium malate, lithium malonate, lithium succinate, lithium tartrate, lithium benzoate.

Lithium toluate, lithium chlorobenzoate.

Lithium nitrobenzoate, lithium aminobenzoate, lithium salicylate, lithium acetylsalicylate, lithium gallate, lithium phthalate, lithium phenylacetate, lithium cinnamate, lithium naphthoate, lithium naphthoate, lithium benzenesulfonate, toluenesulfonic acid Examples include lithium salts of organic aromatic carboxylic acids and sulfonic acids such as lithium, lithium xylene sulfonate, lithium phenolsulfonate, lithium benzenedisulfonate, lithium sulfanilate, lithium aminobenzenesulfonate, and lithium naphthalenesulfonate. However, among these, it is preferable to use lithium salts of organic aromatic carboxylic acids and sulfonic acids, but two or more of these lithium salts may be used in combination.

The content of the lithium salt is 0.01 to 5% by weight, preferably 0.05 to 2% by weight, based on the total weight of the developer when used.
Weight%. When it is less than 0.01% by weight, the effect of the lithium salt is insufficient, and when it is more than 5% by weight, precipitation tends to occur and the concentration of the developer becomes poor.

The developer used in the present invention contains an alkali silicate as an alkaline agent. Examples of the alkali silicate include potassium silicate, sodium silicate, sodium metasilicate, potassium metasilicate, and ammonium silicate.

The content of alkali silicate in the developer is silicon oxide (Si
Oa) The concentration is 0.0% based on the total weight of the developer when used.
1 to 5% by weight is suitable, preferably 0.3 to 2% by weight.

It is preferable to use a potassium salt such as potassium silicate in the developer used in the present invention because it is less likely to form a precipitate in the developer.

The developer used in the present invention may contain alkaline agents other than alkali silicates, such as potassium hydroxide, sodium hydroxide, tribasic sodium phosphate, dibasic sodium phosphate, tribasic potassium phosphate, Inorganic alkaline agents such as potassium diphosphate, tertiary ammonium phosphate, diammonium diphosphate, sodium bicarbonate, )&M sodium, potassium carbonate, ammonium carbonate, etc., mono-, di- or triethanolamines and tetraalkyl hydroxides. An organic alkaline agent can be used in combination.

The pH of the developer used in the present invention is 12 to 13.5. If the pll is less than 12, the developability will be poor, and if the pH exceeds 13.5, the back side of the An support will be discolored.
There are problems such as the image area of the 28th plate being eroded and precipitation occurring.

[510g1/[M] of the developer used in the present invention
(M is an alkali metal other than Li) has a value of 0. []5≦[
5jOtl/rM7 <0.50 Teal, Kono value is O,
If it is less than OS, even if a lithium salt is added, it is no longer possible to prevent the back surface of the support from discoloration, and if it exceeds O or SO, the developability is poor and the developer concentration is poor, making it impossible to achieve the effects of the present invention. I don't get it.

The developer used in the present invention can contain a surfactant, an organic solvent, and an organic carboxylic acid, if necessary.

The surfactant may be nonionic, cationic, anionic, amphoteric, or amphoteric, but is preferably a nonionic surfactant or a cationic surfactant, and more preferably a nonionic surfactant.

Nonionic surfactants include polyethylene glycol type and polyhydric alcohol type, both of which can be used. From the viewpoint of development performance, polyethylene glycol type nonionic surfactants are preferred, and among them, ethyleneoxy group (-
(:H2CH20-) of 3 or more, and IILB value (
IILB is Hydrophile-Lipophile
Abbreviation of Ba1ance) is 5 or more (more preferably 8 to 8)
A nonionic surfactant of 2, more preferably 15 to 20) is more preferred.

Furthermore, among nonionic surfactants, those having both an ethyleneoxy group and a propyleneoxy group are particularly preferred, and among these, those having an HLB value of 8 or more are more preferred.

Preferred examples of nonionic surfactants include the following - Tsuzuriyo (1)
) to [8].

(1) If-Q-(C112(:l120) nil
(2) (6) +10(C2](,0)a-((:21(,
0) b-(C21(,0)cH(8) +1O-(C
H2CI+20)nH (1) ~ In formulas [8], R represents a hydrogen atom or a monovalent organic group, and the organic group is:
For example, a linear or branched substituent having 1 to 3 carbon atoms (
For example, an alkyl group that has an aryl group (such as phenyl), an alkyl carbonyl group whose alkyl moiety is the above-mentioned alkyl group, or a substituent (such as a hydroxyl group or the above-mentioned alkyl group) Examples include a phenyl group and the like. a.

b, c, m, n, x and y each represent an integer of 1 to 40.

Next, specific examples of nonionic surfactants will be shown.

(Specific examples) Polyethylene glycol, polyoxyethylene lauryl ether, polyoxyethylene nonyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene behenyl ether, polyoxyethylene polyoxypropylene cetyl Ether, polyoxyethylene polyoxypropylene behenyl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene stearamide, polyoxyethylene olein amide, Polyoxyethylene castor oil, polyoxyethylene abiethyl ether, polyoxyethylene lanolin ether, polyoxyethylene monolaurate, polyoxyethylene monostearate,
Polyoxyethylene glyceryl monooleate, polyoxyethylene glyceryl monostearate, polyoxyethylene propylene glycol monostearate, oxyethylene oxypropylene block polymer, distyrenated phenol polyethylene oxide adduct, tribenzylphenol polyethylene oxide adduct, octylphenol poly Oxyethylene polyoxypropylene adduct, glycerol monostearate, sorbitan monolaurate, polyoxyethylene sorbitan monolaurate, etc.

The weight average molecular weight of the nonionic surfactant is 30 (1 to 10
A range of 000 is preferred, and a range of 500 to 5000 is particularly preferred.

One type of nonionic surfactant may be contained alone, or two or more types may be used in combination.

Cationic surfactants are broadly classified into amine type and quaternary ammonium salt type, and any of these can be used.

Examples of amine types include polyoxyethylenealkylamines, N-alkylpropyleneamines, N-alkylpolyethylenepolyamines, N-alkylpolyethylenepolyamine dimethyl sulfates, alkyl biguanides, long chain amine oxides, alkylimidacillines, 1-hydroxy Ethyl-2-alkylimidacyline, 1-acetylaminoethyl-2-alkylimidacyline, 2-alkyl-4
-Methyl-4-hydroxymethyloxazoline and the like.

Examples of quaternary ammonium salts include long-chain primary amine salts, alkyltrimethylammonium salts, dialkyldimethylethylammonium salts, alkyldimethylammonium salts, alkyldimethylbenzylammonium salts, alkylpyridinium salts, and alkylquinolinium salts. salt, alkylisoquinolinium salt, alkylpyridinium sulfate, stearamidemethylpyridinium salt, acylaminoethyldiethylamine salt, acylaminoethylmethyldiethylammonium salt, alkylamidopropyldimethylbenzylammonium salt, fatty acid polyethylene polyamide, acylaminoethylpyridinium salt, acylcolaminoformylmethylpyridinium salt, stearoxymethylpyridinium salt, fatty acid triethanolamine, fatty acid triethanolamine formate, trioxyethylene fatty acid triethanolamine 1, fatty acid dibutylaminoethanol, cetyloxymethylpyridinium salt, p -isooctylphenoxyethoxyethyldimethylbenzylammonium salt and the like. ("Alkyl" in the above compound examples refers to straight chain or partially substituted alkyl having 6 to 20 carbon atoms, specifically hexyl,
Straight chain alkyls such as octyl, cetyl and stearyl are preferably used. Among these, water-soluble quaternary ammonium salt type cationic surfactants are particularly effective, and among these, alkyltrimethylammonium salts, alkyldimethylbenzylammonium salts, ethylene oxide-adducted ammonium salts, and the like are preferred. Further, a polymer having a cationic component as a repeating unit is also a cationic surfactant in a broad sense, and the cationic surfactant used in the present invention has a golden color. In particular, a polymer containing a quaternary ammonium salt obtained by copolymerizing with a lipophilic monomer can be suitably used.

The weight average molecular weight of the polymer is in the range of 300 to 5000, particularly preferably in the range of 500 to 5000. These cationic surfactants are better when used alone.
Two or more types may be used in combination.

As anionic surfactants, higher alcohols (Ca
~C22) Sulfuric acid ester salts [e.g., sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, rTeepol-81”
(trade name, manufactured by Shell Chemical), sodium chloride alkyl sulfate, aliphatic alcohol phosphate ester salts (e.g., sodium salt of cetyl alcohol phosphate, etc.), alkylaryl sulfonates (e.g., dodecylbenzenesulfonic acid) sodium salt of isopropylnaphthalenesulfonic acid, sodium salt of sinapthalenedisulfonic acid, sodium salt of metanitrobenzenesulfonic acid, etc.), sulfonate salts of alkylamides (e.g., C+y11:+zCON(C
II+)Ct(2so:+Na etc.), sulfonic acid salts of dibasic fatty acid esters (e.g.

sodium sulfosuccinate dioctyl ester, sodium sulfosuccinate dihexyl ester, etc.)
Among these, sulfonate salts are particularly preferably used.

As the amphoteric surfactant, a compound such as sodium N-methyl-N=pentadecylaminoacetate can be used.

The surfactant is preferably contained in the developer at a concentration in the range of 0.01 to 10% by weight.

The organic solvent contained in the developer used in the present invention preferably has a solubility in water at 20°C of 10% by weight or less, such as ethyl acetate, propyl acetate, butyl acetate, benzyl acetate, ethylene glycol monobutyl acetate. Carboxylic acid esters such as butyl lactate, butyl levulinate; ketones such as ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone; ethylene glycol monobutyl ether, ethylene glycol pencil ether, ethylene glycol monophenyl ether, benzyl alcohol, methyl phenyl Alcohols such as carbinol, n-amyl alcohol, and methylamine alcohol; alkyl-substituted aromatic hydrocarbons such as xylene; halogenated hydrocarbons such as methylene cyclolite, ethylene dichloride, and monochlorobenzene. One or more types of these organic solvents may be used.

The content of the organic solvent in the developer is preferably in the range of 0.05 to 10% by weight.

The organic carboxylic acids include aliphatic carboxylic acids having 6 to 20 carbon atoms and aromatic carboxylic acids in which a benzene ring or a naphthalene ring is substituted with a carboxyl group.

The aliphatic carboxylic acid is preferably an alkanoic acid having 6 to 20 carbon atoms, and specific examples include cafuroic acid, enantylic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, mystylic acid, valmitic acid, and stearin. Examples include acids, and particularly preferred are alkanoic acids having 6 to 12 carbon atoms. Further, the aliphatic carboxylic acid, which may be a fatty acid having a double bond in its carbon chain or a branched carbon chain, may be used as a sodium or potassium salt or an ammonium salt.

Specific compounds of aromatic carboxylic acids include:

Benzoic acid, 0-chlorobenzoic acid, p-chlorobenzoic acid,
0-hydroxybenzoic acid, p-hydroxybenzoic acid,
p-tart-butylbenzoic acid, 0-aminobenzoic acid,
p-aminobenzoic acid, 2,4-dihydroxybenzoic acid,
2,5-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid, gallic acid,
1-hydroxy-2-naphthoic acid, 3-hydroxy-2
-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-
These include naphthoic acid and 2-naphthoic acid.

The above aromatic carboxylic acid may be used as a sodium or potassium salt or an ammonium salt.

There are no particular restrictions on the content of aliphatic carboxylic acids and aromatic carboxylic acids, but if it is less than 0.1% by weight, the effect will not be sufficient, and if it is more than 30% by weight, no further improvement in the effect can be measured. However, this may hinder dissolution when using other additives. Therefore, the amount added is preferably 0-1 to 10% by weight, more preferably 0.5 to 4% by weight.
It is.

The developer used in the present invention may further contain a sulfite. Sulfites include sodium sulfite,
Potassium sulfite, ammonium sulfite, sodium hydrogen sulfite, potassium hydrogen sulfite and the like can be mentioned.

The content of sulfites is 0 based on the total weight of the developer when used.
．． 1 to 10% by weight is suitable, more preferably 0.5
~5% ■%.

In addition to the above, the following additives may be added to the developer used in the present invention in order to enhance the developing performance.
For example, Hacl described in JP-A No. 58-75152,
Neutral salts such as KCfL, K[lr, etc., JP-A-59-190
Chelating agents such as EDTA and NT^ described in Publication No. 952, [C0(N
H3)] Complexes such as 6CJ13, JP-A-56-14225
Ampholytic polymer electrolyte such as a copolymer of vinylbenzyltrimethylammonium chloride and sodium acrylate described in Publication No. 8, S described in JP-A-59-75255
Organometallic surfactant containing i, Ti, etc., JP-A-59-
Examples include organic boron compounds described in Japanese Patent No. 84241.

The method of supplying the developer onto the plate is, for example, by using a shower vibrator or nozzle to spray, spray or drop the liquid onto the plate surface, or from a developer supplying member placed in a position that is in contact with or not in contact with the plate surface. There is a method of supplying a developer by coating it on the printing plate.

The method of bringing the developer supplying member into contact with the 28th plate and supplying the developer onto the 25th plate includes, for example, a method of supplying the developer by rubbing the 28th plate with a water-absorbing member such as a sponge or cloth, or a method of supplying the developer by rubbing the 28th plate with a water-absorbing member such as a sponge or cloth, or a method using a rubber or the like. Regardless of whether it is a non-water-absorbing member or a water-absorbing member such as the sponge or cloth, these members are formed into rollers and the rotation of the roller is synchronized with the photosensitive lithographic printing plate being transported. 1 For example, a method using a flexible plate material such as a film base, bringing the tip of a slit formed by the two plates into contact with a 28 plate, and supplying a developer onto the PS plate from the gap between the slits. Examples include.

In addition, there are two methods for supplying the developer onto the 25th plate without contact between the developer supplying member and the 28th plate: 1, for example, a method of storing the developer in a narrow gap and supplying it by passing the printing plate through the gap; , a method of supplying the 28 plate by bringing it into contact with the developer that hangs down in a rod shape due to surface tension from the developer supply member;
Another method is to store the developer in a cylindrical object, make a narrow gap on the side of the cylindrical object, and supply the developer by passing the 28 plate through the gap.

Further, in these developer supply methods, the developer can be supplied onto the 25th plate not only in liquid form but also in foam form. Furthermore, in the method of supplying the developer by spraying, the developer can also be supplied in the form of a mist.

Other methods of supplying the developer include a method of supplying the developer by attaching the developer to a film base etc. and laminating it on the 25 plate, and a method of supplying the wax-like developer by bringing it into contact with the printing plate. It will be done.

As the developer supply method, only one method may be used, or two or more methods may be used in combination.

In the present invention, the amount of developer supplied onto the printing plate by these methods is between 70 and 70 kg per 1 rr of printing plate.
It's 0 mouths. If the supply rate is less than 70 °C m/m, it will be difficult to develop uniformly on a single plate. If it exceeds 700 °C, the cost will increase and the developer will not be retained on the plate. There are disadvantages in that the developing solution may run down, or the amount of developing solution in the center of the eye may become extremely large, resulting in uneven development.

A more preferable supply amount of the developer is 90 m/m'' to 500 m/m''
- Sentence/rn', especially 100 ■ Sentence/Go to 300-
sentence/m'').

Further, the amount of developer supplied can be changed within the above range depending on the area of one type of printing plate, the area ratio of non-images, the width and length of the plate, etc.

The temperature of the developer during use is 5°C to 60°C, preferably 10°C to 45°C, more preferably 25°C to 35°C.
℃ range.

The developer may be finished into a working solution and stored in a storage tank and supplied onto the 25th plate during processing, or it may be divided into a stock solution and a diluted solution, or multiple solutions with different compositions and stored in a storage tank. ,
Each method may be supplied onto the printing plate, or dynamically mixed at the time of supply to prepare a working solution and supplied, but it is preferable to mix automatically and supply it to the printing plate in a uniform state.

The developer supplied to the printing plate is a substantially unused developer. Here, "substantially" means, as a general rule, the entire amount of new developer, but it may be used within the range that does not impair the effects of the present invention. This means that some of the liquids used once may be mixed and used.

The developer supply section is equipped with a control mechanism linked to a detection mechanism such as a sensor that detects the presence or absence of the 25th plate, and the mechanism is activated before the 25th plate is carried into the developing section and after passing through. It is desirable that it be like this.

In the method of the present invention, it is preferable to add some kind of operation to accelerate the development during the development process.

For the development promotion operation, all physical, chemical, electrical, mechanical, etc. means for promoting development can be used.

Mechanical acceleration means include a method of rubbing the plate surface, for example, a method of rubbing using a rotating roller-like rubbing member, a method of rubbing by rotating a flat rubbing member, a method of rubbing by rotating a flat rubbing member, and a method of rubbing the plate-like rubbing member back and forth and/or left and right. Examples include a method of rubbing by moving a roller-shaped rubbing member or a flat-plate rubbing member while rotating it and moving it back and forth and/or left and right. Note that a plurality of these rubbing members may be used in combination, and these rubbing members can be made using, for example, a brush, a sponge, or cloth.

Other development accelerating means include, for example, a method of blowing high-pressure air, a method of irradiating ultrasonic waves, a method of applying vibration to the PS plate, and an electrochemical development method as described in JP-A-58-42042. A method of instantly heating the developing solution on the 25 plate by microwave irradiation, or a method of honing using a processing solution containing abrasive powder.

The development accelerator may be added before, during or after the developer is supplied, or preferably during or after the developer is supplied.

Further, the developer supplying means and the development promoting means may be integrated, for example, the development promoting means is a disc-shaped brush, and when the developer supplying means is a nozzle, the rotating shaft of the disc-shaped brush It is also possible to install a nozzle in the center of the

In the present invention, the time it takes for the 25th plate to pass through the development zone is 1
It is preferable that the time is 08' to 60 seconds.

The automatic developing machine used to carry out the method of the present invention automatically transports and processes 25 plates, and supplies a predetermined amount of aqueous alkaline developer onto the plate surface for each PS plate during processing. There are no particular limitations on its shape, configuration, structure, etc., as long as it is equipped with means and means for promoting development. It is preferable to use a conveyance method such as a conveyance roller or an endless belt.

In addition to the above-mentioned development process, if necessary, the development process method of the present invention and the automatic developing machine used in the process may include a development stop process (the stop process liquid can be used in a disposable or cyclical manner). ), each individual desensitization process, a development stop process and a subsequent desensitization process, a process that combines a development process and a desensitization process, or a development stop process and a desensitization process. It may include a processing step described in JP-A No. 54-8002 in combination with a fatification processing step, and there may be a plurality of each of the development processing step and other steps, for example, the development processing step may be divided into a first development process and a second development process.

The photosensitive composition of the photosensitive lithographic printing plate used in the present invention contains a photosensitive substance as an essential component, and the physical and chemical properties of the photosensitive substance change upon exposure or subsequent development treatment. 1 For example, there is a difference in solubility in a developer due to exposure, a difference in TLC adhesion between molecules before and after exposure, and a difference in affinity for water and oil due to exposure or subsequent development treatment. It is possible to use those that produce an image, those that can form an image area by electrophotography, and those that have a multilayer structure as described in JP-A-55-166645.

Typical photosensitive substances include, for example, photosensitive diazo compounds, photosensitive azide compounds, compounds with ethylenically unsaturated double bonds, epoxy compounds that undergo polymerization with acid catalysts, and C-〇- compounds that decompose with acids. Examples include compounds having a C group. Typical positive-type compounds that become alkali-soluble upon exposure include 0-quinonediazide compounds, acid-decomposable ether compounds, and ester compounds.

Aromatic diazonium salts are examples of negative-type compounds whose solubility decreases upon exposure to light.

Specific examples of 0-quinonediazide compounds include 1, for example, JP-A-47-5303, JP-A-48-63802, and JP-A-48.
-63803, 49-387 old number, 56-104
No. 4, No. 56-1045, Special Publication No. 41-11222, No. 43-28403, No. 45-9610, No. 49
-17481, U.S. Patent No. 2,797,213, U.S. Patent No. 3
．． No. 046,120, No. 3,188,210, No. 3
, No. 454,400, No. 3,544,323, No.:l
, No. 573,917, No. 3,674.495, No. 3,
785,825, British Patent No. 1,227,602, British Patent No. 1,251. 145, 1,267.005, 1, 329.888, 1,330,932, and German Patent No. 854,890. No. 37549, 60-1024
No. 7, No. 60-3625, etc., and the present invention is preferably applied at least to photosensitive lithographic printing plates using these compounds alone or in combination as photosensitive components. I can do it.

These photosensitive components include 0-quinonediazide sulfonic acid esters or O-quinonediazidecarboxylic acid esters of aromatic hydroxy compounds and 0-quinonediazide sulfonic acid amide or 0-quinonediazidecarboxylic acid amide of aromatic amino compounds; These include those in which the 0-quinonediazide compound is used alone, and those in which it is mixed with an alkali-soluble resin and this mixture is provided as a photosensitive layer.

Alkali-soluble resins include novolak-type phenolic resins, and specifically include phenol formaldehyde resins, cresol formaldehyde resins, phenol-cresol mixed formaldehyde resins, cresol xylenol mixed formaldehyde resins, and the like. Furthermore, as described in JP-A-50-125806, in addition to the above-mentioned phenol resin, phenol or cresol substituted with an alkyl group having 3 to 8 carbon atoms such as t-butylphenol formaldehyde resin and formaldehyde are used. It is also possible to use a condensate of the same. 0
-The photosensitive layer containing a quinonediazide compound as a photosensitive component includes:
If necessary, additives such as dyes, plasticizers, and components imparting printout performance can be added.

The amount per unit area of the photosensitive layer containing the 0-quinonediazide compound as a photosensitive component is preferably about 0.5 to 7 g/rrf.
The present invention can be applied to the range of

The image exposure of the positive photosensitive lithographic printing plate to which the method of the present invention is applied does not need to be particularly changed and may be carried out in accordance with a conventional method.

Typical photosensitive components of the negative photosensitive layer are diazo compounds.1 For example, diazo resin, which is a condensate of diazonium salt and/or p-diazodiphenylamine and formaldehyde, is described in Japanese Patent Publication No. 7364/1983. p
- A diazo resin consisting of an organic solvent-soluble salt of a copolycondensate described in Japanese Patent Publication No. 49-48001, such as a phenol salt or fluorocaprate of diazodiphenylamine, and a condensate of p-diazodiphenylamine and formaldehyde. Examples include -methoxy-4-hydroxy-5-benzoylbenzenesulfonate, tetrafluoroborate of a condensate of p-diazodiphenylamine and formaldehyde, and hexafluorophosphate.

The present invention can be preferably applied at least to negative photosensitive planographic printing plates containing these as photosensitive components.

Although these diazo compounds are used alone, the present invention can also be applied to those used in combination with various resins in order to improve the physical properties of the photosensitive layer. Such resins include shellac, derivatives of polyvinyl alcohol, copolymers having alcoholic hydroxyl groups in side chains as described in JP-A-50-118802, and those described in JP-A-55-155:155. Examples include copolymers with phenolic hydroxyl groups in their side chains.

These resins include the following - copolymers containing at least 50% by weight of structural units that are wetted by the binding margin (wherein R1 represents a hydrogen atom or a methyl group, and R2 represents a hydrogen atom, a methyl group, an ethyl group, or chloromethyl group, n is an integer of 1 to 10) and an aromatic hydroxyl group.
-80 mol%, and 5-90 mol% of acrylic ester and/or methacrylic ester monomer units, and polymer compounds having an acid value of 10-200 are included.

Additives such as dyes, plasticizers, and components imparting printout performance can be added to the photosensitive layer of the negative photosensitive lithographic printing plate to which the developing method of the present invention is applied.

The amount per unit area of the photosensitive layer is at least 0.1 to
The present invention is applicable to the range of 7 God.

The support used in the photosensitive lithographic printing plate is as follows:
Mention may be made of aluminum (including aluminum alloys) or aluminum-coated composite supports.

Further, it is desirable that the surface of the aluminum material be roughened for the purpose of increasing water retention and adhesion to the photosensitive layer.

Examples of surface roughening methods include generally known methods such as brush polishing, ball polishing, electrolytic etching, chemical painting/etching, liquid honing, sandblasting, etc., and combinations thereof. Preferably, brush polishing, electrolytic etching, Chemical etching and liquid honing may be mentioned, of which surface roughening methods involving the use of electrolytic etching are particularly preferred. The electrolytic bath used in electrolytic etching is an aqueous solution containing an acid, an alkali, or a salt thereof, or an aqueous solution containing an organic solvent. A liquid is preferable, and the aluminum plate subjected to the surface roughening treatment is desmutted with an acid or alkali aqueous solution, if necessary.

It is preferable that the aluminum plate thus obtained be anodized, and particularly preferably, the aluminum plate is treated in a bath containing sulfuric acid or phosphoric acid. Further, if necessary, a sealing treatment and other surface treatments such as immersion in an aqueous potassium zirconate solution can be performed.

(Effects of the Invention) According to the present invention, a photosensitive lithographic printing plate that prevents an aluminum support from being attacked by a developer, has excellent developability, can prevent the generation of sludge, and has excellent developer concentration. It is possible to provide a development processing method.

〔Example) Hereinafter, the present invention will be explained in detail with reference to Examples.

Positive PS version rSHP-NJ (manufactured by Konica) 10
0:1m5
The image was exposed for 50 seconds from a distance of m.

The 28th plate exposed in this way was processed using a developer with the following composition.
Development treatments (1) to (11) were performed at 27°C for 20 seconds using an automatic developing machine rPSU-820J (manufactured by Konica).

After development, ink was applied using development ink rsPo-IJ (manufactured by Konica).

(Composition of developer) Developer (1) Water
5670g benzoic acid 1
20g 50% potassium hydroxide solution 260g
Emulgen A-500 (Nonionic surfactant manufactured by Kakoyoshi) 5g Potassium silicate solution (Sing containing 26 weight L K, O containing 13141) Lithium benzoate developer (2) Water Benzoic acid 50% Potassium hydroxide solution Oxalic acid Lithium Fox 5" LL Water Benzoic Acid 50% Potassium Hydroxide Solution 50 g Le Toyo 1" I Surfactant) g 60 g g Potassium silicate solution (Sin, containing 26 weight 2, 20 containing 13 weight 670g 20g 60g 670g 20g Emulgen A-500 (manufactured by Kako, nonionic surfactant) g 60g Lithium oxalate g Lithium benzoate ratio 1JjL solution - Hydrobenzoic acid 0.5g 335g 20g 50% potassium hydroxide solution Emulgen A-500 (manufactured by Kako, nonionic surfactant) Lithium benzoate comparative developer (4) Hydrobenzoic acid 50% potassium hydroxide solution 60g g 42g A Potassium silicate solution (Sioz content 26wt L K, 0 content 13 Weight 2) Lithium benzoate 1 (Liquid) D- Water Benzoic acid 50% potassium hydroxide solution 80g g 410g 20g 70g 730g 20g Emulgen A, 500 (manufactured by Kakogyo, nonionic surfactant) 5g3
0g Lithium benzoate comparison developer (5) Hydrobenzoic acid 50% potassium hydroxide solution Emulgen A-500 (manufactured by Kako V4, diionic surfactant) g 610g 20g 90g g Lithium benzoate 7g Developer solution in each treatment Type, concentration of lithium (Li) salt, pH of developer solution 1[5iO-1/[Ml value and 2 during development]
The amount supplied to the 8th printing plate is as shown in Table 1.

(evaluation) ■ Discoloration on the back side of the aluminum support Evaluation was made visually.

◎: There is no damage.

0: There is almost no yare.

×・The back side turns white.

■Developability The developed image was visually evaluated.

○ Near-fold concentration possible ×: Some insoluble matter was observed after 6-fold concentration.

The above evaluation results are shown in Table 1.

◎: Very good.

O1 good.

×: Bad.

(2) Sedimentability The developer after processing the 100th plate of the 23rd plate was placed in a 100m sample printer and left to stand, and the sedimentation was confirmed and evaluated.

Precipitation occurred in 041 months.

O: Precipitation occurred in 3 weeks.

×・Precipitation occurred in 6 days.

(2) Concentration of developer A developer was prepared by reducing the amount of water from each of the developers having the above compositions, and it was confirmed how concentrated a developer could be.

Evaluation was made visually.

◎: Can be concentrated 8 times.As is clear from the above coating, only when the processing method of the present invention is followed can the effects of the present invention such as discoloration on the back side of the aluminum support, developability, precipitation, and concentration of the developing solution be achieved. I found that I was satisfied at the same time.

In addition, in treatment method (1), lithium benzoate is
As a result of the same treatment except that the concentration was changed to
It became 10% worse than 2), and it was found that the organic Li salt had better concentrating properties.

Claims (1)

[Scope of Claims] A photosensitive lithographic printing plate 1 which, after imagewise exposure of a photosensitive lithographic printing plate having a photosensitive layer on a support, is treated with a substantially unused alkaline developer containing water as a main solvent. In a method for developing a photosensitive lithographic printing plate, in which the developer is supplied to the plate surface of each plate for development, the developer (i) contains 0.01 to 5% by weight of lithium salt, and (ii) has a pH of 12 to 13%. .5, and (i
ii) 0.05≦[SiO_2]/[M]<0.50 (however, M is an alkali metal other than Li), and the amount of development processing solution supplied is 70% per 1 m^2 of the photosensitive planographic printing plate.
A method for developing a photosensitive lithographic printing plate, characterized in that the volume is 700 ml.