JPS6289060A - Developing solution composition and developing method to be commonly used for negative type photosensitive lothographic printing plate and positive type photosensitive printing plate - Google Patents

Abstract

PURPOSE:To obtain a developing soln. compsn. to be commonly used for a negative type photosensitive lithographic printing PS and positive type PS plate and a developing method for the PS plates using such compsn. by incorporating a chelate agent into an alkaline soln. consisting of water as a main solvent. CONSTITUTION:The chelate agent is exemplified by a chelate agent which is soluble in an aq. alkaline soln. and can seal calcium ions and magnesium ions in the aq. alkaline soln. More specifically, the chelate agent having >=50% sealing rate at the pH value exhibited by the developing soln. compsn. to be used or more preferably the chelate agent having >=50% sealing rate at 10.0-13.5pH is used. The amt. of the chelate agent to be added is 0.001-1wt%, more preferably 0.01-0.2wt% by the total weight of the developing soln. compsn. and the chelate agent may be used alone or in combination. The chelate agent may be preliminarily added into the developing soln. compsn. or a developing process is executed by adding the chelate agent to the developing soln. compsn. in the stage of development.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a developer composition and a developing method for a photosensitive lithographic printing plate, and more specifically to a winter type photosensitive lithographic printing plate and a positive type photosensitive lithographic printing. The present invention relates to a developer composition that can be commonly used for plates and a method for developing photosensitive lithographic printing plates using the composition.

[Conventional technology]

Conventionally, when developing photosensitive lithographic printing plates (hereinafter referred to as 28th plate), the composition of compatible developers differs between negative-working PS plates and positive-working photosensitive plain printing, and only a dedicated developer for each can be used to develop the appropriate solution. development was possible. However, even if development is possible using a developer other than a dedicated developer,
A lithographic printing plate with sufficient performance could not be obtained, and negative-type PS
At present, it is practically impossible to commonly process a printing plate and a positive PS plate using the same developer.

On the other hand, Japanese Patent Laid-Open No. 80-64351 describes a common developing method in which both a negative-type PS plate and a positive-type photosensitive planar printing plate are developed in one automatic developer. However, in this technology, development for negative-tone PS plates and development for positive-tone photosensitive lithographic printing are carried out sequentially by placing each developer in separate development baths, which are lined up in separate development baths. Since they are not developed with a developer, a dedicated developer is used for each, making solution management troublesome and making it difficult to perform stable development over a long period of time.

In addition, it was developed as the first development machine in JP-A-57-1, which can commonly develop both the negative 18th plate and the Bonn PS plate.
No. 92952 and No. 80-130741 propose a negative/positive aqueous alkaline developer.

However, with these developers, if you choose the 23rd plate type, you can generally process both the negative PS plate and the positive 28th plate, but when using diluted water for the developer concentrate, the hardness of the diluted water will affect the developability. In addition, the generation of sludge-like precipitates in the developer due to the mixed processing of the negative 28 plate and positive 28 plate is significant, and the stability of developing performance and the ability to process large quantities with automatic processors are affected. There was a problem with long-run processability.

Therefore, with conventionally known developer compositions, it is possible to stably and successfully process both the negative type PS plate and the positive type 28 plate using an automatic processor, and also to stably process a large number of sheets over a long period of time. The current situation is that there is nothing that can be processed.

An object of the present invention is to provide a common developer'e and a composition that can process both the negative 18th plate and the positive 28th plate.

Furthermore, another object of the present invention is to develop the shared developer 'a All e
It is an object of the present invention to provide a development method for processing negative-working and positive-working lithographic printing plates with a material.

Still another object of the present invention is to provide negative 18th edition and positive 2nd edition.
Even when a large number of 8-plate plates are processed over a long period of time using an automatic processor, stable development performance is achieved for both the negative-type 18-plate plate and the Bon-type PS plate. To provide a developer composition and a developing method for negative 18th plate and positive PS plate, which can always provide stable developing performance without fluctuations even when tap water or well water with high hardness is used as water. be.

[Structure of the invention]

The present inventors developed a common development method for the negative 18th plate and positive PS plate in which a chelating agent was contained in an alkaline aqueous solution containing water as the main solvent in the development process of the image-exposed negative 18th plate and positive 28th plate. It has been found that the above object can be achieved by a liquid composition (hereinafter also simply referred to as the developer composition of the present invention) and a negative developing method using the developer composition.

In implementing the present invention, it is preferable that the alkaline aqueous solution contains at least one of an anionic surfactant and a sulfite, and has an H value in the range of 10.0 to 13.5.

Further, the method of the present invention is particularly effective when applied to an automatic processor.

Next, the developer composition of the present invention will be specifically explained.

Examples of the chelating agent used in the present invention include those that are soluble in an alkaline aqueous solution and capable of absorbing calcium ions and magnesium ions in the alkaline aqueous solution. That is, the pH of the developer composition used
A chelating agent having a blocking rate of 50% or more at a pH value of 50% or more, more preferably a blocking rate of 50% or more at a pH of 10.0 to 13.5 is used.

Examples of such chelating agents include ethylenenoaminetitraacetic acid, noethylenetriaminebentaacetic acid, triethylenetetraminehexaacetic acid, hydroxyethylethylenenoaminetriacetic acid, nitrilotriacetic acid, cyclohexanoaminethitraacetic acid, 1,3-noaminoacetic acid, etc. 7minobocarboxylic acids such as -2-propa/-lutetraacetic acid and their sodium salts and potassium salts, 2-phosphonobutane-1,2,4-)licarboxylic acid, 2-phospho7butane-2.3.4-) Ricarboxylic acid, 1-phospho/ethane-
1,2,2-)licarboxylic acid, 1-hydroxyethane-
Examples include organic phosphonic acids or phosphotricarboxylic acids such as 1,1-diphosphonic acid, aminodo (methylene phosphonic acid), and their sodium and potassium salts.

The amount of the above-mentioned chelating agent added is 0.001 to 1% by weight, preferably 0.01% by weight, based on the total amount of the developer.
~0.2% by weight, and can be used alone or in combination. Furthermore, these chelating agents may be added in advance to the developer composition, or the developer SU may be added to the object during development to perform the development process.

The alkaline agents used in the developer composition of the present invention include sodium silicate, potassium silicate, ammonium silicate,
Sodium hydroxide, lithium hydroxide, sodium triphosphate, sodium diphosphate, potassium triphosphate, potassium diphosphate, ammonium diphosphate, ammonium diphosphate, sodium metasilicate, sodium bicarbonate, carbonic acid Inorganic alkaline agents such as sodium, potassium carbonate, ammonium carbonate, etc., organic alkaline agents such as mono-, mono-, or triethylamine and tetraalkylammonium hydroxide, and the like are useful. Among these, alkali silicate is most preferred because it has good development stability. It is suitable to use an alkaline developer in a composition range, and more preferably in a range of 0.1 to 10 weight percent. These alkaline agents can be used in combination so that the pl+ of the developer reaches a desired value.

As anionic surfactants, higher alcohols (C,
~C2□) Sulfuric acid ester salt M [e.g., sodium salt of lauryl alcohol sulfate, sodium salt of octyl alcohol sulfate, ammonium salt of lauryl alcohol sulfate, rTeepol D-8
1J (trade name, manufactured by Shell Chemical Co., Ltd.), secondary sodium alkyl sulfate, etc.], aliphatic alcohol phosphate ester salt M (e.g., sodium salt of cetyl alcohol phosphate ester, etc.), alkylaryl sulfonate M
(For example, sodium salt of dodecylbenzenesulfonic acid, sodium salt of isopropylnaphthalenesulfonic acid, sodium salt of cina7talinnosulfonic acid, sodium salt of metanitrobenzenesulfonic acid, etc.), the content in the sulfone RmlJi of alkylamides is 0 .05 to 20 weight percent of sulfonic acid salts of fatty acid esters (eg, sodium sulfosuccinate nooctyl ester, sodium sulfosuccinate dihexyl ester, etc.). Among these, vrI sulfonates are preferably used.

Sulfite has the function of dissolving soluble noazo resin under water in an aqueous solution, and in particular, when developing a 38-layer plate that is combined with a hydrophobic resin, it can cause stains even if the plate material has been manufactured for a long time. It is possible to create a printed version without Useful sulfites include alkali metal salts such as sodium, potassium, and lithium, alkaline earth metal salts such as magnesium, and ammonium salts.

A solvent may also be added to the developer composition of the present invention. Preferred organic solvents include those having a solubility in filtered water at 20°C of 10% by weight or less,
For example, ethyl acetate, propyl acetate, butyl acetate, benyl acetate, ethylene glycol monobutylacede, butyl lactate, Repreez, acid butyl (e.g. C+7113zC
ONCIIzCI12SOJa etc.), dibasic C1l.

carboxylic acid esters such as ethyl butyl ketone, methyl isobutyl ketone, cyclohexanone; ethylene glycol monobutyl ether, ethylene glycol benol ether, ethylene glycol monophenyl ether, benzyl alcohol, methylphenyl carbinol, n - Alcohols such as amyl alcohol and methyl amyl alcohol; alkyl-substituted aromatic hydrocarbons such as xylene; halogenated hydrocarbons such as methylene dichloride, ethylene dichloride, and monochlorobenzene.

One or more types of these organic solvents may be used. Among the above organic solvents, ethylene glycol monophenyl ether, ethylene glycol benol ether and benzyl alcohol are particularly preferred.

The following additives can be added to the developer composition of the present invention in order to further improve the developing performance.

For example, NaCf described in JP-A-58-75152
1. Neutral salts such as KCf and KDr, JP-A-59-1213
[C.

Ampholytic surfactants such as N-tetradecyl-N, N-dihydroxyethylbetaine described in No. 324, nonionic surfactants such as tetramethyldecynediol described in U.S. Pat. 95
Cationic polymers such as the quaternized methyl chloride of p-methylamino/methylpolystyrene described in No. 946, and amphoteric polymers such as the copolymer of vinylbenzyltrimethylammonium chloride and acrylic acid compound described in JP-A-56-142528. Polymer electrolyte, JP-A-57-
Reducing Kuroiso salts such as sulfite chloride described in JP-A No. 192952, inorganic lithium compounds such as lithium chloride described in JP-A No. 58-59444, organic lithium compounds such as lithium benzoate described in JP-A-50-34442, Si described in JP-A-59-75255.

Organometallic surfactant containing Ti etc., JP-A-59-842
Organoboron compound described in Publication No. 41, European Patent No. 1
Examples include quaternary ammonium salts such as the tetraalkylammonium oxide described in No. 01010.

The 23rd edition photosensitive composition used in the present invention contains a photosensitive substance as an essential component, and the physical and chemical properties of the photosensitive substance do not change upon exposure or subsequent development treatment. For example, there are differences in solubility in developing solutions due to exposure, differences in intermolecular adhesive strength before and after exposure, differences in affinity for water and oil due to exposure or subsequent development, and A device that can form an image area using an electrophotographic method, and
The multilayer structure described in Japanese Patent No. 5-166645 can be used.

Typical photosensitive substances include photosensitive diazo compounds, photosensitive at compounds, compounds with ethylenically unsaturated double bonds, epoxy compounds that polymerize with acid catalysts, silyl ether polymers that decompose with acids, and C-0-
Examples include compounds having a C-group.

As a photosensitive noazo compound, it is a positive type that becomes alkali-soluble upon exposure to light. - Quinonediat compounds, aromatic diazonium salts, etc. are examples of negative-type compounds whose solubility decreases upon exposure to light.

Specific examples of 0-quinone diat compounds include, for example, JP-A-47-5303, JP-A-48-63802, and JP-A-48.
-63803, 49-38701, 56-10
No. 44, No. 56-1045, Special Publication No. 41-1122
No. 2, No. 43-28403, No. 45-9610, No. 49-17481, U.S. Patent t52,797
, No. 213, No. 3,046,120, No. 3,188
, No. 210, No. 3,454,400, No. 3,544,
No. 323, No. 3,573,917, No. 3,674゜495, No. 3,785,825, British Patent No. 1
, 277', No. 602, No. 1.251,345,
No. 1,267.005, No. 1.329,888, fn1. ．． 330,932, German Patent No. 85
No. 4.890, etc., and the present invention can be preferably applied to the 23rd edition in which these compounds are used alone or in combination as photosensitive components.

These photosensitive components include 0-quinone diat sulfonic acid esters of aromatic hydroxy compounds or.

- quinonediazidecarboxylic acid esters, and 0-quinonenoanodosulfonic acids or aromatic amino compounds.

-quinone dianodocarboxylic acid 7amide, and
These include those in which these 0-quinonediat compounds are used alone, and those in which they are mixed with an alkali-soluble resin and this mixture is provided as a photosensitive layer.

Alkali-soluble Og fats include novolac type phenolic resins, specifically, 7-el formaldehyde resin, cresol formaldehyde resin, phenol-cresol mixed formaldehyde resin, cresol xylene 7
- Contains mixed formaldehyde arboreal, etc.

Furthermore, as described in JP-A No. 50-125806, the above-mentioned phenol I (along with Ilffl,
A combination of a phenol substituted with an alkyl group having 3 to 8 carbon atoms or a condensate of cresol and formaldehyde such as butyl 7-ethyl formaldehyde resin can also be used.

If necessary, additives such as dyes, plasticizers, and components imparting printout performance can be added to the photosensitive layer containing the 0-quinonenoanodo compound as a photosensitive component.

The amount per unit area of the photosensitive layer containing the 0-quinonenoanodo compound as a photosensitive component is at least 6 about 0.5 to 7 g/,
The present invention can be applied to the following ranges.

There is no particular need to change the image exposure of the bond type PS plate to which the method of the present invention is applied, and a conventional method may be used.

Typical photosensitive components of the negative photosensitive layer are diazo compounds, such as noazo resin, which is a condensate of noazonium salt, V/or p-noazophenylamine, and formaldehyde, and Japanese Patent Publication No. 52-73 [34 72/-l salt or fluorocapric acid salt of p-)7zonophenylamine described in Japanese Patent Publication No. 1982-48001, 3-notquinophenylamine decazonium described in Japanese Patent Publication No. 49-48001 Noazo resin consisting of an organic solvent soluble salt of a copolycondensate of chloride, 4-nitronophenylamine and formaldehyde, 2-MeFquin-4-hydroxy-5 of a condensate of p-noazinophenylamine and formaldehyde Examples include benzoylbenzene sulfonate, tetrafluoro-7-acid salt of a condensate of p-noazinophenylamine and formaldehyde, and hexafluorophosphate.

The present invention can also be preferably applied to negative PS plates containing these as photosensitive components and various other negative PS plates.

In addition to those in which these diazo compounds are used alone, the present invention can also be applied to those in which they are used in combination with Seed/Z U4 resin in order to improve the physical properties of the photosensitive layer.

Examples of such resins include shellac, derivatives of polyvinyl alcohol, copolymers having an alcoholic hydroxyl group in the side chain described in JP-A-50-118802, and copolymers having an alcoholic hydroxyl group in the side chain described in JP-A-55-155355. Examples include copolymers having the described 7-ethyl hydroxyl groups in their side chains.

These glue! The fat includes a copolymer containing at least 50% by weight of a structural unit represented by the following general formula;
R1 - (CH2-C) - COO- (CIl 2CIIO) -nH (in the formula, R1
represents a hydrogen atom or a methyl group, R2 represents a hydrogen atom, a methyl group, an ethyl group or a chloromethyl group, and I] is an integer of 1 to 10. ) and 1 to 80 mol% of monomer units having an aromatic hydroxyl group, and 5 to 80 mol% of acrylic ester and/or methacrylic ester monomer units.
Polymer compounds having an acid value of 90 mol% and an acid value of 10 to 200 are included.

Additives such as dyes, plasticizers, components imparting print-aft performance, etc. can be added to the photosensitive layer of the negative PS plate to which the processing method of the present invention is applied.

”The amount per unit area of the binary photosensitive layer is at least 0.1
The present invention can be applied to a range of 7 g/m2.

Supports used for the above PS plates include paper,
Plastics (such as polyethylene, polypropylene, polystyrene, etc.), laminated paper, aluminum (including aluminum alloys), metal plates such as zinc, copper, etc., cellulose diacetate, cellulose triacetate, cellulose propionate, Films of plastics such as polyethylene terephthalate, polyethylene polypropylene, polycarbonate, polyvinyl acetal, etc., paper or plastic films laminated or vapor-deposited with the above metals, copper plates plated with aluminum or chrome, etc. Among these, aluminum and aluminum-coated composite supports are particularly preferred.

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

The surface roughening method includes generally known methods such as brush polishing, pole polishing, electrolytic etching, chemical etching, liquid honing, sandblasting, etc., and combinations thereof, preferably brush polishing, electrolytic etching, and chemical etching. Among these, a surface roughening method including the use of electrolytic etching is particularly preferred.As the electrolytic bath used in electrolytic etching, acids, alkalis or their salts are preferred. An aqueous solution containing an organic solvent or an aqueous solution containing an organic solvent is used, and among these, an electrolytic solution containing hydrochloric acid, nitric acid, a combination of hydrochloric acid and nitric acid, or a salt thereof is particularly preferred. Further, the roughened aluminum plate is desmutted with an acid or alkali aqueous solution, if necessary.

It is desirable that the aluminum plate thus obtained is subjected to anodizing treatment, and particularly preferred is a method of treatment in a bath containing sulfuric acid or phosphoric acid. Furthermore, if necessary, surface treatments such as hole treatment (1) and immersion in an aqueous solution of potassium norphinate may be performed.

There are various conventionally known methods for developing the 18th plate using the 11ff developer, such as spraying the developer onto the photosensitive layer of the 18th plate from a number of nozzles, and immersing the photosensitive layer in a large amount of the developer. Method, Subonno “cPS” containing developer
A method of wiping the photosensitive layer of the plate, a method of applying a developer to the photosensitive layer of the 18th plate using a roller, etc. can be used. Further, these developing methods may be the same or a combination of different methods may be used.

In order to promote development, the surface of the photosensitive layer may be rubbed with a brush or the like after the developer is supplied onto the photosensitive layer of the 18th plate as described above, or with the 18th plate immersed in the developer. can. The conditions for development can be set as appropriate depending on the developing method used, but the temperature of the developer during use is generally 5 to 60°C, preferably 10 to 45°C, more preferably 25 to 35°C. It is in the range of C. Moreover, it is preferable that the developing time is 10 to 90 seconds.

In addition, a replenisher may be added to each of the above-mentioned developing solutions depending on the fatigue caused by the development process or the absorption of carbon dioxide in the air. Various conventionally known compositions and replenishment methods can be used for the replenisher.

In the development process of the present invention, in addition to the above development process,
If necessary, a development stop step after development processing (stop solution includes a disposable method or a circulating method), individual processing steps of desensitization processing step, development processing step and subsequent desensitization step, development processing It may also include a treatment step that combines a step and a desensitization step, or a treatment step that combines a development stop 1-treatment step and a desensitization step, such as described in JP-A-54-8002.

〔Example〕

Embodiment 1 A JIS-1050 aluminum plate with a thickness of 0.24+o+o is immersed in a 2% hydroxide) +7um aqueous solution, degreased, and The surface was electrochemically roughened in a nitric acid solution, thoroughly washed, and then anodized in a dilute sulfuric acid solution to form an oxide film of 2.5 g/lo2 on the surface of the aluminum plate. After washing the aluminum plate treated in this way and drying it, a photosensitive solution having the following composition was added to the dry weight of 2
．． Apply to 5g/τ12 and dry to form a positive p
I got the S version.

(Photosensitivity 1 (1j) □ ...0.03
A large number of the thus obtained Bon type PS plates were prepared, a transparent positive film was adhered thereto, and exposure was performed for 60 seconds from a distance of 70 cm using a 2 kilowatt metal halide lamp.

On the other hand, negative-type PS clothing was produced as follows.

A JIS-1050 aluminum plate with a thickness of 0.24111 m (20% phosphoric acid) was immersed in a 17um aqueous solution to degrease it, electrochemically roughened in a dilute hydrochloric acid solution, thoroughly washed, and then soaked in a dilute sulfuric acid solution. 1.5g after anodizing
An oxide film of /Juku 2 was formed on the surface of the aluminum plate. Like this place J! I! aluminum plate,
Furthermore, after performing pore sealing treatment by immersing in an aqueous sodium metasilicate solution, washing with water, and drying, a photosensitive liquid having the following composition was applied to a dry weight of 2.0ε/Ir12, and dried to form a negative type 23 plate. Obtained.

(Photosensitivity: 1ffl) A large number of negative PS plates obtained in this way were prepared, and a transparent negative film 1. were brought into close contact with each other and exposed for 30 seconds from a distance of 70 cm using a 2 kilowatt metal halide lamp.

Also, the development path r! of automatic development fi PSP-860 (manufactured by Konishiroku Photo Industry Co., Ltd.). ! , 30 f of the aqueous alkaline developer shown below was added to the tank, and the developer temperature was adjusted to 25°C for 1!4
I arranged it.

(Developer) 500 parts by weight The pH of the above developer was 12.4 at 25°C.

The photographing feed speed of the automatic developing machine was set so that the developing time was 45 seconds, and 181 liters of water was put into the circulation washing tank in order to perform washing with water as a process of development processing. The above-mentioned image-exposed negative 98 plate and positive PS plate were indiscriminately passed through the automatic developing machine mentioned above, and processed continuously for 20 days at 10010O380 (hm size) at 250 pieces/day. is.

During the development process, the developer was exhausted by the developing process, and the following replenisher was added to keep the activity of the developer the same as the initial developer. As a result, during the 20-day processing, the spray nozzle of the automatic development unit operated normally without clogging. After processing for 20 times, the developer was removed and the generation of scum was examined, and it was found that almost no scum was generated. When the lithographic printing plates that had been developed and washed in this manner were coated with a mulch solution and printed, high-quality printed matter with no stains in the non-image areas was obtained for each printing plate.

(Replenisher) ... 6.6 parts by weight ... 500 parts by weight Comparative Example 1 The same developer and replenisher used in Example 1 except that tetrapotassium ethylene-noaminethitraacetate was removed. The procedure was the same as in Example 1.

As a result, on the 12th day, the spray nozzle of the automatic processor became clogged, and some of the printing plates obtained by the development process suffered from poor development. Further, when the developer was removed after 20 mouths of processing and the degree of generation of scum was examined, it was found that a large amount of scum was generated inside the spray vibrator.

Example 2 A photosensitive #S solution having the following composition was placed on the same aluminum ram support as the positive PS plate in Example 1 at a dry weight of 2.23/ml.
It was coated so as to have a color of 1112 and dried to obtain a positive PS plate.

(Photosensitive solution) A large number of positive type 23 plates thus obtained were prepared, a transparent positive film was adhered thereto, and exposure was performed using a 2 kilowatt metal halide lamp.

On the other hand, on the same aluminum support as the negative PS plate in Example 1, a photosensitive solution of the following composition was applied in dry form with a ffi of 1.8.
g/m2 and dried to obtain a negative type 13 plate.

(Photosensitive liquid) A large number of negative 23 plates obtained in this way were prepared, and a Jyomei negative film was adhered to them, and a 2 kilowatt metal halide lamp was used to illuminate them at a distance of 70 c + n.
Exposure was performed for seconds.

Next, 301 liters of the aqueous alkaline developer shown below was charged into the same automatic development processing section as in Example 1, and the developer temperature was adjusted to 27°C.

The pH of the developer was 12.6 at 25°C.

The conveyance speed of the automatic developing machine is set so that the development time is about 20 seconds, and in order to perform rinsing processing as a step after development processing, 1 portion of the surfactant aqueous solution shown below is added to the rinsing tank.
51 insertion r: When the exposed PS plate was processed in the same manner as in Example 1 under the above conditions, the negative PS plate was 1 0 0 3 +a
+n X8 0 0 +++ M size is 85
It was also possible to process up to 60 sheets of the same size Bong type 23 plate. When the lithographic printing plates that had been developed and rinsed in this manner were coated with a mulch solution and printed, high-quality printed matter with no stains in the non-image areas was obtained in all cases.

Comparative Example 2 The same procedure as in Example 2 was carried out, except that the developer prepared in Example 2 was used, except that 2) IJ-lotriacetate was removed.

As a result, there was a residual film due to poor development in a part of the non-image area of the negative 23rd plate, and when this plate was printed on a printing machine, ink adhered to the non-image area and caused stains.

Example 3 A positive-type 28 plate and a negative-type PS plate obtained in the same manner as in Example 1 were exposed to light under the same conditions as in Example 1 with a large number of sheets of original film attached.

Next, an aqueous alkaline developer 307' was charged into the development processing section of an automatic processor similar to that in Example 1 as follows.
The developer temperature was adjusted to 25°C. A layer line developer prepared in advance with the composition shown in F is prepared, diluted with the same volume of hard water of US hardness 200 (+ 11 After adding and stirring well, it was injected into the above development processing section.

The pH of the diluted developer finished as described above is 25.
It was 12.7 at °C. The development time and post-development treatment were the same as in Example 1. As a result, negative type P
The S version is 1003 + aL6X 800 + oa + size up to 90 sheets, and the same size positive type 28 version is 63 sheets.
When the printing plate obtained was printed on a printing machine, good printed matter was obtained without any stains.

〔Effect of the invention〕

By using the development tL set composition jib development method of the present invention, it is possible to efficiently and commonly process negative PSm and positive 28 plates, and moreover, after processing a large number of plates for a long time, it is possible to Stable development processing became possible for each Type 1'S plate.

Furthermore, even when using tap water with high hardness or well water as dilution water when diluting the developing concentrate or replenishing concentrate, the developing performance will not change and the automatic developing machine will not be affected by long-term use of the developing liquid. Since clogging of shower pipes is also improved, processing operations can be simplified and processing costs can be reduced.

Claims (3)

[Claims] (1) A developer composition for both negative-working photosensitive lithographic printing plates and positive-working photosensitive lithographic printing plates, which is characterized by containing a chelating agent in an alkaline solution containing water as the main solvent. (2) the alkaline solution containing the chelating agent further contains at least one of an anionic surfactant and a sulfite;
The developer composition for use in negative photosensitive lithographic printing plates and positive photosensitive lithographic printing plates according to claim 1, wherein the pH value is in the range of 10.0 to 13.5. . (3) The patent covers the common processing of negative-working photosensitive lithographic printing plates and positive-working photosensitive lithographic printing plates with the same developer composition containing a chelating agent in an alkaline solution containing water as the main solvent. A method for developing photosensitive lithographic printing plates.