JPH06230563A - Photosensitive planographic printing plate and production of planographic printing plate - Google Patents

Abstract

PURPOSE:To enable the stable execution of processing without exchanging a developer over a long period of time by using a coating layer contg. a specific metal oxide, org. metallic compd. and plasticizer as a back coating layer. CONSTITUTION:This planographic printing plate has a photosensitive layer on one surface of an aluminum base having anodically oxidized films on both surfaces and is provided with the coating layer contg. the org. metallic compd. or the metal oxide obtd. by hydrolysis and polycondensation of an org. or inorg. metallic compd., the org. high-polymer compd. and the plasiticizer on the surface on the side opposite to the photosensitive layer. The photosensitive planographic printing plate is subjected to image exposing and is developed with an aq. alkaline soln. of >=12pH contg. alkaline metal silicate. The more preferable embodiment is the aq. soln. of the alkaline metal silicate which compensates the change in the developer by the development by adding a replenishing soln. consisting of an aq. soln. of the alkaline metal silicate to this developer, has 0.3 to 1.0 [SiO21]/[M2O] ratio of the development replenishing soln. and contains 0.5 to 4.0wt.% SiO2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive lithographic printing plate having aluminum as a support and a method for producing a lithographic printing plate using the same. The present invention relates to a lithographic printing plate and a plate making method.

[0002]

2. Description of the Related Art Conventionally widely used positive-working photosensitive lithographic printing plates have an aluminum plate as a support provided with a photosensitive layer comprising an o-quinonediazide compound. It is known that an o-quinonediazide compound is converted to a carboxylic acid by exposure to ultraviolet light, and therefore, when this is developed with an aqueous alkaline solution, only the exposed portion of the photosensitive layer is removed and the surface of the support is exposed.
Since the surface of the aluminum support is hydrophilic, the portion where the surface of the support is exposed by development (non-image area) retains water and repels the oil-based ink. On the other hand, the area (image area) where the photosensitive layer has not been removed by the development is lipophilic and thus repels water and accepts ink. Various alkaline aqueous solutions are known to be used as developers for such positive-working photosensitive lithographic printing plates, but most preferred are silicate aqueous solutions such as sodium silicate and potassium silicate. The reason is that the developability is controlled to some extent by the ratio (generally expressed by the molar ratio [SiO ₂ ] / [M ₂ O]) of silicon oxide SiO ₂ and the alkali metal oxide M ₂ O, which are the components of silicate, and the concentration. This is because it is possible.

These silicates are not limited to the above-mentioned positive-working photosensitive lithographic printing plates, but also negative-working photosensitive lithographic printing plates for reversal processing using an o-quinonediazide photosensitive layer described in JP-B-56-14970. , A developer of a negative photosensitive lithographic printing plate using an alkali-soluble diazonium salt as a photosensitive layer and a negative photosensitive lithographic printing plate using a photosensitive layer containing a resin containing a dimethylmaleimide group in a side chain as a photocrosslinking agent. It is also preferably used as a developing solution.

In recent years, automatic developing machines for photosensitive lithographic printing plates have been widely used in the plate making / printing industry in order to rationalize and standardize the plate making work. This automatic developing machine generally consists of a device that conveys the photosensitive lithographic printing plate, a developer tank and a spray device.The exposed photosensitive lithographic printing plate is conveyed horizontally while spraying the developer drawn up by a pump. It is developed by spraying from a nozzle. Further, recently, a method has also been known in which a photosensitive lithographic printing plate is immersed and conveyed by a submerged guide roll or the like into a developing treatment tank filled with a developing solution to perform a developing treatment.

In JP-A-54-62004, when a positive photosensitive lithographic printing plate is developed using such an automatic processor, the molar ratio of SiO ₂ / Na ₂ O as a developer is 1. 0 to
1.5 (that is, [SiO ₂ ] / [Na ₂ O] is 1.0 to 1.5) and the content of SiO ₂ is 1 to 4% by weight, and an aqueous solution of sodium silicate is used. Depending on the throughput of the positive type photosensitive lithographic printing plate, the molar ratio of SiO ₂ / Na ₂ O may be changed continuously or intermittently.
By adding an aqueous sodium silicate solution (replenisher) of 0.5 to 1.5 (that is, [SiO ₂ ] / [Na ₂ O] of 0.5 to 1.5) to the developer, It is disclosed that a large amount of positive-working photosensitive lithographic printing plates can be processed without changing the developing solution.

However, even in such a developing method, when a larger amount of the photosensitive lithographic printing plate is processed, an insoluble matter is generated in the developing solution, which adheres to the lithographic printing plate or clogs the nozzles. There was a drawback that the filter was clogged. It is known that the generation of such insoluble matter is remarkable when a positive photosensitive lithographic printing plate using an aluminum plate having an anodized film as a support is developed. As a technique for improving this drawback, Japanese Patent Publication No. 57-7427 discloses that
[SiO ₂ ] / [M] is 0.5 to 0.75 (that is, [SiO ₂ ] / [M ₂
O] of 1.0 to 1.5) and a concentration of SiO ₂ of 1 to 4% by weight is used, and a developing solution of an alkali metal silicate is used. ₂ ] / [M]
Is 0.25 to 0.75 (that is, [SiO ₂ ] / [M ₂ O] is 0.5 to 1.
5) and wherein both the developer and the replenisher contain at least 20% potassium based on the grams of total alkali metal present therein. ing. Although the generation of insoluble matter was suppressed by this, the activity of the developing replenisher was slightly inferior,
There was a drawback that the replenishment amount was large. To improve this drawback, there is a technique disclosed in Japanese Patent Application Laid-Open No. 2-3065, in which development is carried out by an automatic developing machine having an immersion developing section provided with a floating lid for preventing the developer surface from contacting with air. There is still a strong demand to reduce running costs and waste liquid. Especially today, when environmental conservation is discussed on a global scale, there is a greater demand for reduction of industrial waste.

European Patent Application Publication No. 0490515A discloses a surface of an aluminum support opposite to a surface having a photosensitive layer when the photosensitive lithographic printing plate is developed (hereinafter, this surface is referred to as a back surface of the support). From the results, a large amount of aluminum anodic oxide film is eluted, which clearly shows that this is the cause of insoluble matter formation. Then, as a countermeasure, it is disclosed that it is effective to provide a coating layer made of an organic polymer compound on the surface opposite to the surface having the photosensitive layer.
However, depending on the type of protective layer used, the protective layer swells due to the chemicals used during printing, printing pressure changes, and printing durability deteriorates. Further, it has been found that by providing only the hydrophobic organic polymer compound on the back surface, a lipophilic substance such as ink adheres to the back surface to stain the back surface while the lithographic printing plate is used.

On the other hand, Japanese Patent Laid-Open No. 3-90388 discloses that
A method of treating the back surface of a photosensitive lithographic printing plate with an alkali metal silicate to suppress dusting of the back surface by a developing solution is disclosed. However, this method is complicated because it is necessary to keep the temperature of the treatment liquid at a high temperature of 50 to 90 ° C., and further alkali treatment is performed after the treatment, and the treatment liquid is a highly alkaline aqueous solution and only uniform coating property is poor. However, if the processing liquid spills over to the photosensitive layer side, there is a problem such that the adhesion between the photosensitive layer and the aluminum support is reduced. Further, in Japanese Patent Application No. 4-189448, a layer made of a metal compound obtained by hydrolyzing and polycondensing an organic metal compound or an inorganic metal compound is provided on the back surface of a photosensitive lithographic printing plate, and aluminum is eluted from the back surface. A method of preventing this is disclosed. However, in this method, the coating solution scattered around the coating part during manufacturing and dried up, but it cannot be easily removed with an organic solvent, so if the coating is carried out intermittently over a long length, the coating accuracy of the bar, coater, etc. will gradually increase. Deteriorated,
There is a problem that stable coating cannot be performed. Further, the dried solid matter could be removed to some extent with a strong acid or a strong alkali, but it was not always sufficient from the viewpoint of the deterioration of the material of the peripheral member of the coating portion or the safety in handling work. Further, in this method, if the material is scattered on a material having a very poor adhesion and is dried to a thick thickness, it may peel off like scales and fly finely to cause dust and the like during application, which may cause a coating failure. . In addition, the back surface treated by this method has a surface hardness due to inorganic substances, so if it is transported in multiple layers without a slip sheet, or if it is handled during plate making such as stacking multiple sheets without a slip sheet. It was easy to scratch the photosensitive layer side (front side).

[0009]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a photosensitive lithographic printing plate having improved manufacturability which can reduce the amount of developer replenishment and industrial waste, and a method using the same. It is to provide a method for producing a lithographic printing plate. Another object of the present invention is to provide a photosensitive lithographic printing plate having improved aptitude for production, which does not form an insoluble matter even after a large amount of treatment for a long period of time, and can be stably treated, and a plate-making method thereof. It is to be. Still another object of the present invention is that there is no drawback that lipophilic substances such as developing ink adhere to the back surface of the support to stain it, and further, a large amount of the photosensitive lithographic printing plate is processed by an automatic developing machine for a long period of time. Also provides a photosensitive lithographic printing plate having improved manufacturability, which enables stable processing without the need to replace the developing solution for a long period of time without producing insoluble matter in the developing solution, and a processing method thereof. It is to be. Still another object is to provide a photosensitive lithographic printing plate having improved manufacturing suitability without problems such as scratches even when interleaving interleaving paper which is industrial waste is removed, and a processing method thereof.

[0010]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have shown that they exhibit hydrophobicity before development, excellent developer resistance, and hydrophilicity after development. As the backcoat layer shown, a coating layer containing a metal oxide obtained by a sol-gel method, an organic polymer compound and a plasticizer was found to be excellent, and the present invention has been completed. That is, the present invention has a photosensitive layer on one surface of an aluminum support having an anodized film on both sides, and an organic metal compound or an inorganic metal compound is hydrolyzed and polycondensed on the surface opposite to the photosensitive layer. It is intended to provide a photosensitive lithographic printing plate comprising a coating layer containing the obtained metal oxide, an organic polymer compound and a plasticizer.
The present invention also provides a method for producing a lithographic printing plate, which comprises subjecting the above-mentioned photosensitive lithographic printing plate to imagewise exposure and developing with an alkaline aqueous solution containing an alkali metal silicate and having a pH of 12 or more. In a preferred embodiment of the present invention, the change in the developing solution due to the development is compensated by adding a replenishing solution consisting of an aqueous solution of an alkali metal silicate to the developing solution, and the developing replenishing solution is [SiO ₂ ] / [M ₂ O] ratio (where [SiO ₂ ] is the molar concentration of SiO ₂ (mol / l), [M ₂ O]
] Is the molar concentration of the oxide M ₂ O of alkali metal M (mol /
l)) is 0.3-1.0 and SiO ₂ is 0.5-4.0.
It is an aqueous solution of a weight% alkali metal silicate. The photosensitive lithographic printing plate (hereinafter referred to as PS plate) of the present invention will be described in detail below.

[0011]

[Support] The support used in the PS plate of the present invention is a plate made of aluminum and an aluminum alloy, and a plate made of aluminum or an aluminum alloy bonded to both sides of paper or plastic. Is used. Suitable aluminum plates are a pure aluminum plate and an alloy plate containing aluminum as a main component and containing a slight amount of a foreign element, and may be a plastic film on which aluminum is laminated or vapor-deposited. The foreign elements contained in the aluminum alloy include silicon, iron, manganese, copper, magnesium, chromium, zinc, bismuth, nickel and titanium. The content of foreign elements in the alloy is at most 10% by weight. Aluminum suitable for the present invention is pure aluminum, but completely pure aluminum is difficult to produce due to refining technology, and thus may contain slightly different elements. Thus, the aluminum plate applied to the present invention, the composition is not specified, conventionally publicly known material, for example JIS A1050, JIS A1100
, JIS A3003, JIS A3103, JIS A3005, etc. can be appropriately used. The aluminum plate used in the present invention has a thickness of about 0.1 mm to 0.6 mm.

Before the surface roughening of the aluminum plate, if desired, a degreasing treatment for removing rolling oil on the surface is carried out, for example, with a surfactant, an organic solvent or an alkaline aqueous solution. First, the surface of the aluminum plate is subjected to a surface roughening treatment. As the method, a method of mechanically roughening the surface, a method of electrochemically melting and roughening the surface, and a method of selectively melting the surface chemically There is a way. As a mechanical method, a known method called a ball polishing method, a brush polishing method, a blast polishing method, a buff polishing method, or the like can be used. As an electrochemical graining method, there is a method of performing alternating current or direct current in a hydrochloric acid or nitric acid electrolytic solution. Further, as disclosed in Japanese Patent Laid-Open No. 54-63902, a method in which both a mechanical surface roughening method and an electrochemical surface roughening method are combined can be used. The thus roughened aluminum plate is subjected to an alkali etching treatment and a neutralization treatment, if necessary, and then subjected to an anodic oxidation treatment, if desired, in order to enhance water retention and abrasion resistance of the surface. As the electrolyte used for anodizing the aluminum plate, any electrolyte that forms a porous oxide film can be used, and generally sulfuric acid, phosphoric acid, oxalic acid, chromic acid or a mixed acid thereof is used. The concentration of these electrolytes is appropriately determined depending on the type of electrolyte.

The anodizing condition varies depending on the electrolyte used and cannot be unconditionally specified. Generally, however, the concentration of the electrolyte is 1 to 80% by weight solution, the liquid temperature is 5 to 70 ° C., and the current density is 5 to 5. 60 A / dm ² , a voltage of 1 to 100 V, and an electrolysis time of 10 seconds to 5 minutes are suitable. Among them, sulfuric acid as an electrolyte, a method of anodizing at a high current density as described in British Patent No. 1,412,768 and a low concentration sulfuric acid aqueous solution as described in U.S. Patent No. 4,211,619. The method of anodic oxidation is preferable, in which the concentration of sulfuric acid is 5 to 20% by weight, the concentration of dissolved aluminum ions is 3 to 15% by weight, and the current density is 5 to 20 A / dm ² in the electrolytic solution at a temperature of 25 to 50 ° C. The method of anodic oxidation with direct current is the most preferable. The amount of the anodized film is suitably 1.0 g / m ² or more, but more preferably in the range of 2.0 to 6.0 g / m ^2. If the anodic oxide film is less than 1.0 g / m ² , printing durability is insufficient, or the non-image area of the planographic printing plate is easily scratched, and ink adheres to the scratched portion during printing. Scratch stains are likely to occur. Such anodizing treatment is applied to the surface of the lithographic printing plate support used for printing.
Generally, an m ² anodic oxide film is formed. After being subjected to anodizing treatment, the aluminum surface is optionally subjected to hydrophilic treatment. As the hydrophilic treatment used in the present invention, U.S. Patent Nos. 2,714,066 and 3,181,461.
No. 3,280,734 and 3,902,734, there are alkali metal silicate (eg aqueous sodium silicate) processes. In this method, the support is immersed or electrolyzed in an aqueous sodium silicate solution. Besides, potassium fluorozirconate disclosed in JP-B-36-22063 and US Pat. Nos. 3,276,868, 4,153,461 and 4,689,272.
For example, a method of treating with polyvinylphosphonic acid as disclosed in Japanese Patent Publication No. 2004-242242 is used.

[0014]

[Organic Undercoat Layer] The aluminum plate is optionally provided with an organic undercoat layer before coating the photosensitive layer. Examples of the organic compound used in this organic undercoat layer include carboxymethyl cellulose, dextrin, gum arabic, and 2-
Phosphonic acids having an amino group such as aminoethylphosphonic acid, optionally substituted phenylphosphonic acid, naphthylphosphonic acid, alkylphosphonic acid, glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid and other organic phosphones Acids, phenylphosphoric acid which may have a substituent, naphthylphosphoric acid, organic phosphoric acid esters such as alkylphosphoric acid and glycerophosphoric acid, phenylphosphinic acid which may have a substituent, naphthylphosphinic acid, alkylphosphinic acid and It is selected from organic phosphinic acids such as glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydrochlorides of amines having a hydroxyl group such as hydrochlorides of triethanolamine. Good.

This organic undercoat layer can be provided by the following method. That is, water or a solvent in which the above organic compound is dissolved in an organic solvent such as methanol, ethanol, methyl ethyl ketone or a mixed solvent thereof is applied on an aluminum plate and dried to provide a method, and water or methanol, ethanol, methyl ethyl ketone, etc. In a solution prepared by dissolving the above organic compound in the organic solvent or a mixed solvent thereof, the aluminum plate is immersed to adsorb the above organic compound, and then washed with water or the like and dried to form an organic undercoat layer. Is the way. In the former method, a solution having a concentration of 0.005 to 10% by weight of the above organic compound can be applied by various methods. For example, any method such as bar coater coating, spin coating, spray coating, or curtain coating may be used. Also, in the latter method, the concentration of the solution is 0.01 to 20% by weight, preferably 0.05 to 5% by weight, and the immersion temperature is 20 to 90 ° C, preferably 25.
Is about 50 ° C., and the immersion time is 0.1 second to 20 minutes, preferably 2 seconds to 1 minute. The pH of the solution used for this is adjusted with basic substances such as ammonia, triethylamine and potassium hydroxide, and acidic substances such as hydrochloric acid and phosphoric acid.
It can also be used in the range of pH 1-12. Further, a yellow dye may be added to improve the tone reproducibility of the photosensitive lithographic printing plate. The coating amount of the organic undercoat layer after drying is 2
~ 200 mg / m ² is suitable, preferably 5-100 mg
/ M ² . If the coating amount is less than 2 mg / m ² , sufficient printing durability cannot be obtained. The same applies when the amount is larger than 200 mg / m ² .

[0016]

[Backcoat layer] On the back surface of the support of the PS plate of the present invention, an organic metal compound or an organic metal compound obtained by hydrolyzing and polycondensing an organic metal compound or an inorganic metal compound in order to suppress the elution of the anodized film of aluminum is formed. A coating layer containing a polymer compound and a plasticizer (hereinafter, this coating layer is referred to as a back coat layer) is provided. Examples of the metal oxide used in the back coat layer include silica (silicon oxide), titanium oxide, boron oxide, aluminum oxide, zirconium oxide, and a complex thereof. The metal oxide in the backcoat layer used in the present invention is a so-called hydrolyzed organometallic compound or inorganic metallic compound in water and an organic solvent with a catalyst such as an acid or an alkali, and a polycondensation reaction. It is obtained by applying the sol-gel reaction solution to the back surface of the support and drying. Examples of the organic metal compound or the inorganic metal compound used here include metal alkoxides, metal acetylacetonates, metal acetates, metal oxalates, metal nitrates, metal sulfates, metal carbonates, metal oxychlorides, metal chlorides. And a condensate obtained by partially hydrolyzing them to form an oligomer.

The metal alkoxide is M (OR)_nGeneral formula of
(M is a metal element, R is an alkyl group, and n is a metal
Indicates the oxidation number of the element). An example is Si (OCH₃)_Four,
Si (OC₂H_Five)_Four, Si (OC₃H₇)_Four, Si (OC_FourH₉)_Four, Al (OCH₃)₃, Al
(OC₂H_Five)₃, Al (OC₃H₇)₃, Al (OC_FourH₉)₃, B (OCH₃)₃, B (OC₂H
_Five)₃, B (OC₃H₇)₃, B (OC_FourH₉)₃, Ti (OCH₃)_Four, Ti (OC ₂H
_Five)_Four, Ti (OC₃H₇)_Four, Ti (OC_FourH₉)_Four, Zr (OCH₃)_Four, Zr (OC
₂H_Five)_Four, Zr (OC₃H₇)_Four, Zr (OC_FourH₉)_FourAre used.
Besides, Ge, Li, Na, Fe, Ga, Mg, P, Sb, Sn, Ta, V, etc.
The alkoxide of is mentioned. Furthermore, CH₃Si (OCH₃)₃,
C₂H_FiveSi (OCH₃)₃, CH ₃Si (OC₂H_Five)₃ , C₂H_FiveSi (OC₂H_Five)₃Such
The mono-substituted silicon alkoxide of is also used. Metal acetyl
An example of luacetonate is Al (COCH₂COCH₃)₃, Ti (C
OCH₂COCH₃) _Four, And so on. Examples of metal oxalates
As K₂TiO (C₂O_Four)₂As an example of metal nitrates, Al
(NO₃)₃, ZrO (NO₃)₂・ 2H₂There is O etc. Metal sulphate
Al as an example₂(SO_Four)₃, (NH_Four) Al (SO_Four)₂, KAl (SO_Four)₂,
NaAl (SO_Four)₂, Si as an example of metal oxychloride₂OCl₆,
ZrOCl₂, AlCl as an example of chloride₃, SiCl_Four, ZrCl₂, T
iCl_Fourand so on.

These organic metal compounds or inorganic metal compounds may be used alone or in combination of two or more. Among these organic metal compounds or inorganic metal compounds, metal alkoxides are preferable because they are highly reactive and easily form a polymer formed from a metal-oxygen bond. Among them, Si (OCH ₃ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Si (O
Silicon alkoxy compounds such as C ₃ H ₇ ) ₄ and Si (OC ₄ H ₉ ) ₄ are particularly preferable because they are inexpensive and easily available, and a metal oxide coating layer obtained therefrom has excellent developer resistance. Further, oligomers obtained by partially hydrolyzing and condensing these alkoxy compounds of silicon are also preferable. An example of this is an average pentameric ethyl silicate oligomer containing about 40 wt% SiO ₂ . Further, it is preferable to use a so-called silane coupling agent in which one or two alkoxy groups of the above-mentioned silicon tetraalkoxy compound are substituted with an alkyl group or a reactive group. Examples of silane coupling agents used for this purpose include vinyltrimethoxysilane, vinyltriethoxysilane, γ
(Methacryloxypropyl) trimethoxysilane, β-
(3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N- β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, methyl Examples include trimethoxysilane and methyltriethoxysilane.

On the other hand, as the catalyst, organic and inorganic acids and alkalis are used. Examples include hydrochloric acid, sulfuric acid,
Inorganic acids such as sulfurous acid, nitric acid, nitrous acid, hydrofluoric acid, phosphoric acid, phosphorous acid, formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, chloroacetic acid, dichloroacetic acid, trichloroacetic acid, fluoroacetic acid, bromoacetic acid, methoxyacetic acid , Oxaloacetate,
Citric acid, oxalic acid, succinic acid, malic acid, tartaric acid, fumaric acid, maleic acid, malonic acid, ascorbic acid, benzoic acid, substituted benzoic acids such as 3,4-dimethoxybenzoic acid, phenoxyacetic acid, phthalic acid, picrin Acid, nicotinic acid, picolinic acid, pyrazine, pyrazole, dipicolinic acid, adipic acid, p-toluic acid, terephthalic acid, 1,
Organic acids such as 4-cyclohexene-2,2-dicarboxylic acid, erucic acid, lauric acid, n-undecanoic acid and ascorbic acid, hydroxides of alkali metals and alkaline earth metals, ammonia, ethanolamine, diethanolamine, triethanol Examples include alkalis such as amines. In addition, sulfonic acids, sulfinic acids, alkylsulfates, phosphonic acids, phosphoric acid esters, and the like, specifically, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethyl acid, phenylphosphonic acid Organic acids such as phenylphosphinic acid, phenyl phosphate, and diphenyl phosphate can also be used. These catalysts can be used alone or in combination of two or more kinds. The catalyst is 0.00 with respect to the raw metal compound.
1 to 10% by weight is preferable, more preferably 0.05 to 5
It is in the range of% by weight. If the amount of the catalyst is less than this range, the initiation of the sol-gel reaction will be delayed, and if it is more than this range, the reaction will proceed rapidly and non-uniform sol-gel particles will be formed. Inferior to.

In order to initiate the sol-gel reaction, a further suitable amount of water is required, and the preferable addition amount thereof is 0.05 to the amount of water necessary for completely hydrolyzing the metal compound as the raw material.
The molar amount is preferably 50 times, and more preferably 0.5 to 30 times. If the amount of water is less than this range, hydrolysis is difficult to proceed, and if it is more than this range, the reaction is also difficult to proceed probably because the raw material is diluted. A solvent is further added to the sol-gel reaction solution. The solvent may be one that dissolves the metal compound as the raw material and dissolves or disperses the sol-gel particles generated by the reaction, and lower alcohols such as methanol, ethanol, propanol and butanol, acetone, methyl ethyl ketone and diethyl ketone. Ketones are used. Further, for the purpose of improving the coating surface quality of the back coat layer, mono- or dialkyl ethers of glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol and dipropylene glycol, and acetic acid ester can be used. Of these solvents, lower alcohols that are miscible with water are preferred. The sol-gel reaction solution is prepared with a solvent to a concentration suitable for coating, but if the whole amount of the solvent is added to the reaction solution from the beginning, the hydrolysis reaction may be difficult to proceed because the raw materials are diluted. Therefore, a method in which a part of the solvent is added to the sol-gel reaction solution and the remaining solvent is added when the reaction proceeds is preferable.

The sol-gel reaction proceeds by mixing a metal oxide raw material, water, a solvent and a catalyst. The progress of the reaction depends on the kind, composition ratio, temperature and time of the reaction, and affects the film quality after film formation. Since the influence of the reaction temperature is particularly large, it is preferable to control the temperature during the reaction.
In addition to the above-mentioned essential components, the sol-gel reaction solution contains sol-
A compound containing a hydroxyl group, an amino group, or active hydrogen in the molecule may be added in order to appropriately adjust the gel reaction. These compounds include polyethylene glycol, polypropylene glycol, block copolymers thereof, and their monoalkyl ethers or monoalkylaryl ethers, various phenols such as phenol and cresol, polyvinyl alcohol and copolymerization with other vinyl monomers. Examples thereof include hydroxyl group-containing acids such as coalesce, malic acid and tartaric acid, aliphatic and aromatic amines, formaldehyde and dimethylformaldehyde. Further, it is preferable to add an organic polymer compound in order to improve the affinity of the dried solid of the coating liquid for an organic solvent and solubilize it.

Examples of the organic polymer compound in the back coat layer used in the present invention include polyvinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyvinyl phenol, polyvinyl halogenated phenol, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, polyamide, Polyurethane, polyurea, polyimide, polycarbonate, epoxy resin, phenol novolac, or condensation resin of resolphenol with aldehyde or ketone, polyvinylidene chloride, polystyrene, silicone resin, active methylene, phenolic hydroxyl group, sulfonamide group, carboxyl group, etc. And an acrylic copolymer having an alkali-soluble group, and a binary or ternary or more copolymer resin thereof.
Particularly preferred compounds are specifically phenol novolac resins or resole resins, and include phenol, cresol (m-cresol, p-cresol, m / p mixed cresol), phenol / cresol (m-cresol, p-cresol, m / p mixed cresol), phenol-modified xylene, tert-butylphenol, octylphenol, resorcinol, pyrogallol, catechol, chlorophenol (m-Cl, p-Cl), bromophenol (m-Br, p-Br), salicylic acid, furo Examples thereof include a novolak resin and a resole resin that are condensed with formaldehyde such as roglucinol, and a condensation resin of the above phenol compound and acetone.

Other suitable polymer compounds include copolymers having the following monomers (1) to (12) as the constitutional units and usually having a molecular weight of 10,000 to 200,000. (1) Acrylamides, methacrylamides, acrylates, methacrylates and hydroxystyrenes having aromatic hydroxyl groups, such as N- (4
-Hydroxyphenyl) acrylamide or N- (4
-Hydroxyphenyl) methacrylamide, o-, m-
And p-hydroxystyrene, o-, m- and p-
Hydroxyphenyl acrylate or methacrylate, (2) acrylic acid esters and methacrylic acid esters having an aliphatic hydroxyl group, for example, 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate, (3) methyl acrylate, ethyl acrylate, acrylic Propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, phenyl acrylate, benzyl acrylate, 2-chloroethyl acrylate, 4-hydroxybutyl acrylate, glycidyl acrylate, N- (Substituted) acrylic acid ester such as dimethylaminoethyl acrylate, (4) methyl methacrylate,
Ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, octyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-chloroethyl methacrylate, 4-hydroxybutyl methacrylate, (Substituted) methacrylic acid esters such as glycidyl methacrylate and N-dimethylaminoethyl methacrylate,

(5) Acrylamide, methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N-ethylacrylamide, N-ethylmethacrylamide, N-hexylacrylamide, N
-Hexyl methacrylamide, N-cyclohexyl acrylamide, N-cyclohexyl methacrylamide, N
-Hydroxyethyl acrylamide, N-hydroxyethyl acrylamide, N-phenyl acrylamide, N
-Phenylmethacrylamide, N-benzylacrylamide, N-benzylmethacrylamide, N-nitrophenylacrylamide, N-nitrophenylmethacrylamide, N-ethyl-N-phenylacrylamide and N-ethyl-N-phenylmethacrylamide. Alternatively, methacrylamide, (6) ethyl vinyl ether, 2-chloroethyl vinyl ether, hydroxyethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, octyl vinyl ether,
Vinyl ethers such as phenyl vinyl ether,
(7) Vinyl esters such as vinyl acetate, vinyl chloroacetate, vinyl butyrate and vinyl benzoate, (8) styrenes such as styrene, methyl styrene and chloromethyl styrene, (9) methyl vinyl ketone,
Vinyl ketones such as ethyl vinyl ketone, propyl vinyl ketone and phenyl vinyl ketone, (10) olefins such as ethylene, propylene, isobutylene, butadiene and isoprene,

(11) N-vinylpyrrolidone, N-vinylcarbazole, 4-vinylpyridine, acrylonitrile, methacrylonitrile, etc. (12) N- (o-aminosulfonylphenyl) acrylamide, N- (m-aminosulfonylphenyl) ) Acrylamide, N- (p-
Aminosulfonylphenyl) acrylamide, N- [1
-(3-aminosulfonyl) naphthyl] acrylamide, acrylamides such as N- (2-aminosulfonylethyl) acrylamide, N- (o-aminosulfonylphenyl) methacrylamide, N- (m-aminosulfonylphenyl) methacrylamide, N- (p-aminosulfonylphenyl) methacrylamide, N- [1-
Methacrylamides such as (3-aminosulfonyl) naphthyl] methacrylamide, N- (2-aminosulfonylethyl) methacrylamide, o-aminosulfonylphenyl acrylate, m-aminosulfonylphenyl acrylate, p-aminosulfonylphenyl acrylate. , Unsaturated sulfonamides such as acrylic acid esters such as 1- (3-aminosulfonylphenylnaphthyl) acrylate, o-aminosulfonylphenyl methacrylate, m-aminosulfonylphenyl methacrylate, p-aminosulfonylphenyl methacrylate, 1- (3 -Unsaturated sulfonamites such as methacrylic acid esters such as aminosulfonylphenylnaphthyl) methacrylate.

These have a weight average molecular weight of 500 to 20000.
The number average molecular weight is preferably 200 to 60,000, and the addition amount is specifically 1 with respect to the metal compound as the raw material.
~ 200 wt% is suitable, 2-100 wt% is more preferred, and 5-50 wt% is most preferred. If the amount added is larger than this, the back coat layer will peel off due to the chemicals used during printing, and the original function will be impaired. In addition, when a lipophilic substance such as ink adheres to the back surface, the original hydrophilicity of the sol-gel deteriorates, and the ink becomes very difficult to put down.

Further, a plasticizer is added together with the above-mentioned organic polymer compound in order to prevent the troubles such as dusts during the production coating accompanying the scale-like exfoliation of the dried product of the coating liquid, in order to make the film flexible. To do. Examples of the plasticizer in the back coat layer used in the present invention include dimethyl phthalate and
Diethyl phthalate, dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, butyl benzyl phthalate, diisodecyl phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, diisobutyl phthalate, octyl capryl phthalate, dicyclohexyl phthalate , Ditridecyl phthalate, diallyl phthalate, dimethyl glycol phthalate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, triethylene glycol dicaprylic acid ester, trioctyl trimellitate, dioctyl adipate, dioctyl Azelate, dibutyl sebacate, dioctyl sebacate, methyl acetyl Noreto, dimethyl maleate,
Diethyl malate, dibutyl malate, dioctyl malate, dibutyl fumarate, dioctyl fumarate, adipic acid-propylene glycol ester, adipic acid-1,3 butylene glycol ester, glycerol triacetate, glycerol tributyrate, cellulose acetate phthalate, trimethyl Phosphate, triethylphosphate, tributylphosphate, trioctylphosphate, tributoxyethylphosphate, trischloroethylphosphate, trisdichloropropylphosphate, mono-2,3-dichloropropyl-bis-2,3-dibromopropylphosphate, triphenylphosphate, Tricresyl phosphate,
Trixylenyl phosphate, cresyl diphenyl phosphate, diphenyl monoorthoxenyl phosphate, octyl diphenyl phosphate, triphenyl phosphite, trilauryl trithiophosphite, trischloroethyl phosphite, trilauryl phosphite, trisnonyl phenyl phosphite, tris Dinonyl phenyl phosphite, dibutyl hydrogen diene phosphite, isopropyl acid phosphate, butyl acid phosphate, dibutyl phosphate, octyl acid phosphate, dioctyl phosphate, isodecyl acid phosphate, monoisodecyl phosphate, tridecanol acid phosphate, etc. are effective. . Among them, one having a boiling point of 250 ° C. or higher at 760 mmHg is particularly effective. In addition, since the stain resistance is not deteriorated due to the adhesion of the lipophilic substance at the time of plate making, it is preferably as hydrophilic as possible. The plasticizer is added within a range such that the back coat layer does not become sticky, but 1 to 100% by weight is suitable for the metal compound as a raw material, 3 to 60% by weight is more preferable, and 5 to 30% by weight is most preferable. This is because if the addition amount is larger than this, lipophilic substances such as ink adhere to the back surface and stain easily.

In the back coat layer of the present invention, it is preferable to use a surfactant for the purpose of adjusting slipperiness. Preferred examples of the surfactant include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene polystyryl phenyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, glycerin fatty acid partial esters, sorbitan. Fatty acid partial ester, pentaerythritol fatty acid partial ester, propylene glycol monofatty acid ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid partial ester, polyethylene glycol fatty acid ester, poly Glycerin fatty acid partial esters, polyoxyethylenated castor oil, polyoxyethylene glycerin fatty acid partial esters, fatty acids Ethanol amides, N, N-
Nonionic surfactants such as bis-2-hydroxyalkylamines, polyoxyethylenealkylamines, triethanolamine fatty acid esters, trialkylamine oxides, fatty acid salts, abietic acid salts, hydroxyalkanesulfonic acid salts, alkanesulfonic acid salts,
Dialkylsulfosuccinate ester salts, linear alkylbenzene sulfonates, branched chain alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkylphenoxypolyoxyethylenepropyl sulfonates,

Polyoxyethylene alkylsulfophenyl ether salts, N-methyl-N-oleyl taurine sodium salt, N-alkylsulfosuccinic acid monoamide disodium salt, petroleum sulfonates, sulfated tallow oil, sulfate ester of fatty acid alkyl ester Salts, alkyl sulfate ester salts, polyoxyethylene alkyl ether sulfate ester salts, fatty acid monoglyceride sulfate ester salts, polyoxyethylene alkylphenyl ether sulfate ester salts, polyoxyethylene styryl phenyl ether sulfate ester salts, alkyl phosphate ester salts, polyoxy Ethylene alkyl ether phosphate ester salts, polyoxyethylene alkylphenyl ether phosphate ester salts, partial saponification products of styrene / maleic anhydride copolymers, Partial saponification products of reffin / maleic anhydride copolymers, anionic surfactants such as naphthalene sulfonate formalin condensates, alkylamine salts, quaternary ammonium salts, polyoxyethylene alkylamine salts, polyethylene polyamine derivatives, etc. And cationic amphoteric surfactants such as carboxybetaines, aminocarboxylic acids, sulfobetaines, aminosulfates, and imidazolines. Among the above-mentioned surfactants, those having polyoxyethylene can be read as polyoxyalkylenes such as polyoxymethylene, polyoxypropylene and polyoxybutylene, and these surfactants are also included.

A more preferred surfactant is a fluorinated surfactant containing a perfluoroalkyl group in the molecule. Such fluorine-based surfactants include perfluoroalkylcarboxylates, perfluoroalkylsulfonates, anionic types such as perfluoroalkyl phosphates, and amphoteric types such as perfluoroalkylbetaines.
Cationic type and perfluoroalkylamine oxide such as perfluoroalkyltrimethylammonium salt, perfluoroalkylethylene oxide adduct, perfluoroalkyl group- and hydrophilic group-containing oligomer,
Nonionic types such as perfluoroalkyl group- and lipophilic group-containing oligomers, perfluoroalkyl groups, hydrophilic group- and lipophilic group-containing oligomers, and perfluoroalkyl group- and lipophilic group-containing urethanes can be mentioned. The above-mentioned surfactants can be used alone or in combination of two or more kinds.
%, More preferably 0.01 to 5% by weight.

The back coat layer of the present invention may further contain a dye or pigment for coloring to discriminate the plate type. Examples of preferred dyes are rhodamine 6G chloride, rhodamine B chloride, crystal violet, malachite green oxalate, oxazine 4 perchlorate, quinizarine, 2- (α-naphthyl) -5-phenyloxazole, coumarin-4. Can be mentioned. As other dyes, specifically, Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Green BG, Oil Blue BOS, Oil Blue # 603,
Oil Black BY, Oil Black BS, Oil Black T-505 (above, Orient Chemical Industry Co., Ltd.)
Made), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42)
535), ethyl violet, methylene blue (CI
52015), patent pure blue (manufactured by Sumitomo Mikuni Kagaku), brilliant blue, methyl green, erythricin B, basic fuchsin, m-cresol purple, auramine, 4-p-diethylaminophenyliminafutoquinone, cyano-p-diethylaminophenylacetanilide and the like. Triphenylmethane system,
Examples thereof include diphenylmethane type dyes, oxazine type dyes, xanthene type dyes, iminonaphthoquinone type dyes, azomethine type dyes and anthraquinone type dyes. The above dye is usually contained in the back coat layer in an amount of about 0.05 to 10% by weight, more preferably about 0.5.
~ 5% by weight.

The backcoat layer of the present invention is further provided with an o-naphthoquinonediazide compound, a photosensitive azide compound, a photopolymerizable composition containing an unsaturated double bond-containing monomer as a main component, a cinnamic acid or a dimethylmaleimide group. A cross-linkable composition and a diazonium salt monomer, or a diazo resin obtained by condensing an aromatic diazonium salt and a reactive carbonyl group-containing organic condensing agent, particularly aldehydes such as formaldehyde and acetaldehyde, or acetals in an acidic medium are used. It can be added for improving. Among these, as an o-naphthoquinonediazide compound known as a positive photosensitive compound, an o-naphthoquinonediazide compound described later in the positive photosensitive layer is preferably used.
The most typical aromatic diazonium salt is a condensate of p-diazodiphenylamine and formaldehyde. The synthesis method of these diazo resins is, for example,
U.S. Pat.Nos. 2,679,498, 3,050,502 and 3,31
Nos. 1,605 and 3,277,074. Further, as a diazonium salt, Japanese Patent Publication No.
A co-condensation diazonium compound of an aromatic diazonium salt described in 8,001 and a substituted aromatic compound containing no diazonium group is preferably used, and among them, an aromatic compound substituted with an alkali-soluble group such as a carboxyl group or a hydroxyl group. A co-condensed diazo compound with is preferred. Furthermore, JP-A-4
-18559, 4-190361, 4-172.
A diazonium salt compound obtained by condensing an aromatic diazonium salt with a reactive carbonyl compound having an alkali-soluble group described in JP-A No. 353 is also used.

As the counter anion of these diazonium salts, there are diazonium compounds using inorganic anions such as mineral acids such as hydrochloric acid, hydrobromic acid, sulfuric acid and phosphoric acid or double salts with zinc chloride, but substantially water. Particularly preferred are insoluble and organic solvent-soluble diazonium compounds. Such preferable diazonium compounds are described in detail in JP-B-47-1167 and U.S. Pat. No. 3,300,309. Furthermore, JP-A-54-98613 and JP-A-56-1
A diazonium compound having a counter anion of halogenated Lewis acid such as tetrafluoroboric acid and hexafluorophosphoric acid and perhalogen acid such as perchloric acid and periodic acid as described in JP-A No. 21031 is preferably used. . In addition, JP-A-58-209733 and 62-17.
The diazonium compounds having a long-chain alkyl group-containing sulfonic acid as a counter anion, which are described in Japanese Patent Nos. 5731 and 63-262643, are also preferably used. The diazonium compound is contained in the photosensitive layer in an amount of 0.5 to 60% by weight, preferably 5 to 50% by weight.

In the back coat layer, higher fatty acids and higher fatty acid amides such as behenic acid, behenic acid amide, stearic acid, stearic acid amide, and alkenylsuccinic anhydride, waxes, dimethylsiloxanes, polyethylene powders, etc. are further used as lubricants. Added. In addition, silica fine powder, colloidal silica, methanol silica sol, boric anhydride and the like are added to the back coat layer in order to improve hydrophilicity and improve film properties. The thickness of the back coat layer used in the present invention may basically be such that the elution of the anodized film of aluminum during development can be suppressed, and 0.00
The range of 1 to 10 g / m ² is preferable, and more preferably 0.0.
1 to 1 g / m ² is preferable, and 0.02 to 0.1 g / m ² is most preferable. Although various methods can be applied as a method for coating the back surface of the aluminum support with the back coat layer, the most preferable method for ensuring the above coating amount is a method of forming a solution and coating and drying.

[0035]

[Photosensitive layer] Thus, a backcoat layer is provided on the back surface and a photosensitive layer made of a known photosensitive composition is provided on an aluminum plate having a hydrophilic surface to obtain a photosensitive lithographic printing plate. Examples of the photosensitive composition include a positive type containing an o-quinonediazide compound as a main component, a diazonium salt, an alkali-soluble diazonium salt, a photopolymerizable compound containing an unsaturated double bond-containing monomer as a main component, and a cinnamic acid or a dimethylmaleimide group. A negative type photosensitizer containing a photocrosslinkable compound containing a compound is used.

[0036]

[Positive-type photosensitive layer] Of these, as an o-naphthoquinonediazide compound used as a positive-type photosensitive composition,
1, 2 described in JP-B-43-28403
Esters of diazonaphthoquinonesulfonic acid and pyrogallol-acetone resin are preferred. Other suitable orthoquinonediazide compounds include, for example, US Pat.
There are esters of 1,2-diazonaphthoquinone-5-sulfonic acid and a phenol-formaldehyde resin described in 3,046,120 and 3,188,210, which are disclosed in JP-A-2-96163 and JP-A-2-9616.
There are esters of 1,2-diazonaphthoquinone-4-sulfonic acid with a phenol-formaldehyde resin described in JP-A No. 5 and JP-A No. 2-967671. Other useful o-naphthoquinonediazide compounds include those known in numerous patents and the like. For example, JP-A-47-5303 and JP-A-48-63802.
No. 48, No. 48-63803, No. 48-96575, No. 49-38701, No. 48-13854, and Japanese Patent Publication No. 3
7-18015, 41-1122, 45-9
610, 49-17481, U.S. Pat. No. 2,7
No. 97,213, No. 3,454,400, No. 3,544,323, No.
No. 3,573,917, No. 3,674,495, No. 3,785,825,
British patents 1,227,602, 1,251,345, 1,2
67,005, 1,329,888, 1,330,932, and German Patent No. 854,890 can be mentioned.

The o-naphthoquinonediazide compound particularly preferred in the present invention is a compound obtained by reacting a polyhydroxy compound having a molecular weight of 1,000 or less with 1,2-diazonaphthoquinonesulfonic acid. Specific examples of such compounds are described in JP-A-51-139402 and JP-A-5-139402.
8-150948, 58-203434, 59
-165053, 60-12145, 60-
134235, 60-163043, 61-1
No. 18744, No. 62-10645, No. 62-106.
No. 46, No. 62-153950, No. 62-17856.
No. 2, 64-76047, U.S. Pat. No. 3,102,809.
No. 3, No. 3,126,281, No. 3,130,047, No. 3,14
No. 8,983, No. 3,184,310, No. 3,188,210, No.
Examples thereof include those described in each publication or specification such as 4,639,406.

When synthesizing these o-naphthoquinonediazide compounds, it is preferable to react 0.2-1.2 equivalents of 1,2-diazonaphthoquinonesulfonic acid chloride with the hydroxyl group of the polyhydroxy compound. .3
More preferably, the reaction is carried out at about 1.0 equivalent. Examples of 1,2-diazonaphthoquinonesulfonic acid chloride include 1,2
-Diazonaphthoquinone-5-sulfonic acid chloride or 1,2-diazonaphthoquinone-4-sulfonic acid chloride can be used. The obtained o-naphthoquinonediazide compound is a mixture of 1,2-diazonaphthoquinonesulfonic acid ester groups having different positions and introduction amounts, but all of the hydroxyl groups are 1,2.
The proportion of the diazonaphthoquinonesulfonic acid esterified compound in the mixture (content of the completely esterified compound) is preferably 5 mol% or more, more preferably 20 to 99 mol%. is there. The amount of these positive-working photosensitive compounds (including combinations as described above) occupying in the photosensitive composition of the present invention is from 10 to 10.
50% by weight is suitable, and more preferably 15-40% by weight.

The o-quinonediazide compound alone can form the photosensitive layer, but it is preferable to use a resin soluble in alkaline water together as a binder. As such a resin soluble in alkaline water, there are novolac type resins such as phenol formaldehyde resin, o-, m- and p-cresol formaldehyde resin, m / p-mixed cresol formaldehyde resin, phenol / cresol ( o-, m-, p-, m /
mixed formaldehyde resin and the like may be used. Further, phenol-modified xylene resin, polyhydroxystyrene, polyhalogenated hydroxystyrene, and an acrylic resin containing a phenolic hydroxyl group as disclosed in JP-A-51-34711 can also be used. As other suitable binder, the above-mentioned (1) mentioned as an example of the monomer forming the polymer compound added to the back coat layer.
To (12) monomers, and (13) acrylic acid,
A copolymer having an unsaturated carboxylic acid such as methacrylic acid, maleic anhydride or itaconic acid as a constitutional unit and having a molecular weight of usually 10,000 to 200,000 can be mentioned.

Further, a monomer copolymerizable with the above-mentioned monomer may be copolymerized. Further, a copolymer obtained by copolymerizing the above-mentioned monomers is also modified, for example, with glycidyl acrylate, glycidyl methacrylate, etc., but is not limited thereto. The above copolymer preferably contains an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic anhydride or itaconic acid listed in (13), and a preferable acid value of the copolymer is 0 to 10 meq. / G, more preferably 0.2-5.0
meq / g. The preferred molecular weight of the above copolymer is 10,000 to 100,000. Further, polyvinyl butyral resin, polyurethane resin, polyamide resin and epoxy resin may be added to the above-mentioned copolymer, if necessary. Such alkali-soluble polymer compounds can be used alone or in combination of two or more, and are used in an amount of 80% by weight or less of the total photosensitive composition. Further, as described in US Pat. No. 4,123,279, t-
It is preferable to use a condensate of formaldehyde and a phenol having an alkyl group having 3 to 8 carbon atoms as a substituent, such as butylphenol formaldehyde resin and octylphenol formaldehyde resin, together in order to improve the oil sensitivity of the image.

Cyclic acid anhydrides, phenols and organic acids are preferably added to the photosensitive composition of the present invention in order to enhance sensitivity. Examples of cyclic acid anhydrides are phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, 3,6-entoxy-Δ ⁴ -tetrahydrophthalic anhydride, and tetrachlorophthalic anhydride described in U.S. Pat. No. 4,115,128. , Maleic anhydride, chloromaleic anhydride, α-phenyl maleic anhydride, succinic anhydride, pyromellitic dianhydride, etc. can be used. Examples of phenols include bisphenol A, p-nitrophenol, p-ethoxyphenol, 2,4.
4'-trihydroxybenzophenone, 2,3,4-trihydroxybenzophenone, 4-hydroxybenzophenone, 4,4 ', 4 "-trihydroxy-triphenylmethane, 4,4', 3", 4 "-tetrahydroxy −
3,5,3 ', 5'-tetramethyltriphenylmethane and the like can be mentioned. Further, as organic acids, Japanese Patent Laid-Open No.
0-88942, JP-A-2-96755 and the like include sulfonic acids, sulfinic acids, alkylsulfates, phosphonic acids, phosphoric acid esters and carboxylic acids, and specifically, p-toluene. Sulfonic acid, dodecylbenzenesulfonic acid, p-toluenesulfinic acid, ethylsulfate, phenylphosphonic acid, phenylphosphinic acid, phenyl phosphate, diphenyl phosphate,
Benzoic acid, isophthalic acid, adipic acid, p-toluic acid, 3,4-dimethoxybenzoic acid, phthalic acid, terephthalic acid, 1,4-cyclohexene-2,2-dicarboxylic acid, erucic acid, lauric acid, n-undecane Acid, ascorbic acid, etc. are mentioned. The proportion of the cyclic acid anhydrides, phenols and organic acids in the photosensitive composition is preferably 0.05 to 15% by weight, more preferably
It is 0.1 to 5% by weight.

Further, in the photosensitive composition of the present invention, in order to broaden the stability of processing (so-called development latitude) with respect to developing conditions, JP-A-62-251740, JP-A-2-96760, and JP-A-2-96760 have been used. Nonionic surfactants such as those described in JP-A-68355 and amphoteric surfactants such as those described in JP-A-59-121044 and JP-A-4-13149 can be added. . Specific examples of the nonionic surfactant include sorbitan tristearate, sorbitan monopalmitate, sorbitan trioleate, stearic acid monoglyceride, polyoxyethylene sorbitan monooleate, and polyoxyethylene nonylphenyl ether. Specific examples of the amphoteric surfactant include alkyldi (aminoethyl) glycine, alkylpolyaminoethylglycine hydrochloride, 2-alkyl-N-carboxyethyl-N-hydroxyethylimidazolinium betaine and N.
-Tetradecyl-N, N-betaine type (for example, trade name Amogen K, manufactured by Daiichi Kogyo Co., Ltd.) and alkyl imidazoline series (for example, trade name Levon 15, manufactured by Sanyo Kasei Co., Ltd.) and the like. The proportion of the nonionic surfactant and the amphoteric surfactant in the photosensitive composition is preferably 0.05 to 15% by weight, more preferably 0.05% by weight.
It is 1 to 5% by weight.

In the photosensitive composition of the present invention, a printout agent for obtaining a visible image immediately after exposure and a dye or pigment as an image colorant can be added. Typical examples of the printout agent include a combination of a compound that releases an acid upon exposure (photoacid releasing agent) and an organic dye capable of forming a salt. Specifically, JP-A-50-3620
No. 9 and 53-8128
-A combination of naphthoquinone diazide-4-sulfonic acid halogenide and a salt-forming organic dye, and JP-A-53-36223.
No. 54, No. 54-74728, No. 60-3626, No. 6
Examples include combinations of trihalomethyl compounds and salt-forming organic dyes described in JP-A Nos. 1-143748, 61-151644 and 63-58440. Such trihalomethyl compounds include oxazole-based compounds and triazine-based compounds, both of which have excellent stability over time and give a clear printout image.
As the image colorant, other dyes can be used in addition to the above-mentioned salt-forming organic dye. Suitable dyes, including salt-forming organic dyes, include oil-soluble dyes and basic dyes. Specifically, Oil Yellow # 10
1, oil yellow # 103, oil pink # 312,
Oil Green BG, Oil Blue BOS, Oil Blue # 603, Oil Black BY, Oil Black B
S, Oil Black T-505 (above, manufactured by Orient Chemical Industry Co., Ltd.), Victoria Pure Blue, Crystal Violet (CI42555), Methyl Violet (CI42535), Ethyl Violet, Rhodamine B (CI145170B), Malachite Green (CI).
42000), methylene blue (CI52015) and the like. Also, JP-A-62-29324
The dyes described in Japanese Patent Publication No. 7 are particularly preferable.

The photosensitive composition of the present invention is dissolved in a solvent which dissolves the above-mentioned components and applied on an aluminum plate of a support. As the solvent used here, the organic solvents described in JP-A-62-251739 are used alone or in combination. The photosensitive composition of the present invention is dissolved and dispersed at a solid content concentration of 2 to 50% by weight, coated on a support and dried. The coating amount of the layer (photosensitive layer) of the photosensitive composition coated on the support varies depending on the use, but generally it is 0.3 to 4.0 by weight after drying.
g / m ² is preferred. The smaller the coating amount, the smaller the exposure amount for obtaining an image, but the film strength decreases. As the coating amount increases, the exposure amount is required, but the photosensitive film becomes stronger. For example, when used as a printing plate,
A printing plate with a high printable number (high printing durability) can be obtained. In the photosensitive composition of the present invention, a surfactant for improving the coating surface quality, for example, JP-A-62-170950 is used.
Fluorine-based surfactants such as those described in Japanese Patent Publication No. 2003-242242 can be added. The preferred addition amount is 0.001 to 1.0% by weight of the total photosensitive composition, and more preferably 0.0.
It is from 0.5 to 0.5% by weight.

[0045]

[Negative-Type Photosensitive Layer] The photosensitive composition of a negative PS plate to which the back coat layer of the present invention is applied is a photosensitive layer containing a photosensitive diazo compound, a photopolymerizable photosensitive layer, a photocrosslinkable photosensitive layer. Examples thereof include those having layers and the like, and of these, the photocurable photosensitive copying material comprising a photosensitive diazo compound will be described in detail with examples. The photosensitive diazo compound used in the PS plate of the present invention is a diazo resin obtained by condensing an aromatic diazonium salt and a reactive carbonyl group-containing organic condensing agent, particularly aldehydes such as formaldehyde and acetaldehyde, or acetals in an acidic medium. Is preferably used. The most typical one is a condensate of P-diazophenylamine and formaldehyde. Methods for synthesizing these diazo resins are described, for example, in US Pat.
No. 9,498, No. 3,050,502, No. 3,311,605 and No. 3,277,074. Further, as the photosensitive diazo compound, Japanese Patent Publication No. 49-48,001
A co-condensation diazo compound of an aromatic diazonium salt and a substituted aromatic compound not containing a diazonium group described in JP-A No. 1993-107242 is preferably used, and among them, an aromatic compound substituted with an alkali-soluble group such as a carboxyl group or a hydroxyl group. The co-condensed diazo compound of is preferable. Furthermore, JP-A-4-18559
Photosensitive diazo compounds obtained by condensing an aromatic diazonium salt with a reactive carbonyl compound having an alkali-soluble group described in JP-A Nos. 4-190361 and 4-172353 are also preferably used.

As a counter anion of these diazonium salts, there is a diazo resin using an inorganic anion such as a mineral acid such as hydrochloric acid, hydrobromic acid, sulfuric acid and phosphoric acid, or a double salt with zinc chloride. Insoluble and organic solvent-soluble diazo resins are particularly preferable. Such preferable diazo resins are described in detail in JP-B-47-1167 and U.S. Pat. No. 3,300,309. Furthermore, JP-A-54-98
Nos. 613 and 56-121031, diazo compounds having halogenated Lewis acids such as tetrafluoroboric acid and hexafluorophosphoric acid and perhalogen acids such as perchloric acid and periodic acid as counter anions. Resin is preferably used. Further, JP-A-58-209733,
The diazo resins having a long-chain alkyl group-containing sulfonic acid as a counter anion described in JP-A Nos. 62-175731 and 63-262643 are also preferably used. The photosensitive diazo compound is contained in the photosensitive layer in an amount of 5 to 50% by weight, preferably 8 to 20% by weight.

The photosensitive diazo compound used in the present invention is preferably used in combination with a lipophilic polymer compound soluble or swellable in alkaline water as a binder. As such a lipophilic polymer compound, the same (1) as that used in the positive photosensitive composition described above can be used.
To (13) as a constitutional unit, usually 1
Examples thereof include copolymers having a molecular weight of 10,000 to 200,000, and polymer compounds obtained by copolymerizing the monomers shown in the following (14) and (15) as constituent units can also be used. (14) Maleimide, N-acryloylacrylamide, N-acetylacrylamide, N-propionylacrylamide, N- (p-chlorobenzoyl) acrylamide, N-acetylacrylamide, N-acryloylmethacrylamide, N-acetylmethacrylamide,
Unsaturated imides such as N-propionyl methacrylamide, N- (p-chlorobenzoyl) methacrylamide,
(15) Side chains of N- [6- (acryloyloxy) -hexyl] -2,3-dimethylmaleimide, N- [2- (methacryloyloxy) -hexyl] -2,3-dimethylmaleimide, vinylcinnamate, etc. An unsaturated monomer having a crosslinkable group. Further, a monomer copolymerizable with the above-mentioned monomer may be copolymerized. Further, a copolymer obtained by copolymerizing the above-mentioned monomers is also modified, for example, with glycidyl acrylate, glycidyl methacrylate, etc., but is not limited thereto. The above-mentioned copolymer preferably contains the unsaturated carboxylic acid listed in (13), and the preferable acid value of the copolymer is 0 to 10 meq / g, more preferably 0.2 to
It is 5.0 meq / g.

The preferred molecular weight of the above copolymer is 10,000 to 1
It is 0,000. Further, polyvinyl butyral resin, polyurethane resin, polyamide resin and epoxy resin may be added to the above-mentioned copolymer, if necessary. It is also possible to use a novolac type resin, a phenol-modified xylene resin, polyhydroxystyrene, polyhalogenated hydroxystyrene, or an alkali-soluble resin containing a phenolic hydroxyl group as disclosed in JP-A-51-34711. it can. Such alkali-soluble polymer compounds can be used alone or in combination of two or more, and usually 40 to 95 is contained in the solid content of the whole photosensitive composition.
It is contained in the range of% by weight.

In the photosensitive composition of the present invention, an oil-sensitizing agent for improving the oil-sensitivity of an image (for example, an alcohol of a styrene-maleic anhydride copolymer described in JP-A-55-527) is used. Half-esterified product, novolac resin, 50% fatty acid ester of p-hydroxystyrene, etc.) are added. Furthermore, a plasticizer for imparting flexibility and abrasion resistance to the coating film is added, for example, butylphthalyl, polyethylene glycol, tributyl citrate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, dioctyl phthalate, Examples include tricresyl phosphate, tributyl phosphate, trioctyl phosphate, tetrahydrofurfuryl oleate, acrylic acid or methacrylic acid oligomers and polymers, of which tricresyl phosphate is particularly preferred. Further, in the photosensitive composition of the present invention, in order to spread stability over time, for example, phosphoric acid, phosphorous acid, citric acid, oxalic acid, dipicolinic acid, benzenesulfonic acid, naphthalenesulfonic acid, sulfosalicylic acid, 4 -Methoxy-2-hydroxybenzophenone-5-sulfonic acid, tartaric acid and the like are added.

Further, in the photosensitive composition of the present invention, a printout agent for obtaining a visible image immediately after exposure and a dye such as a dye or a pigment as an image colorant can be added. As the dye, those that change color tone by reacting with free radicals or acids are preferably used. For example, Victoria Pure Blue BOH (Hodogaya Chemical),
Oil Yellow # 101, Oil Yellow # 103, Oil Pink # 312, Oil Red, Oil Green B
G, oil blue BOS, oil blue # 603, oil black BY, oil black BS, oil black T-505 (above, manufactured by Orient Chemical Industry Co., Ltd.), patent pure blue (manufactured by Sumitomo Mikuni Chemical Co., Ltd.), crystal violet ( CI 42555), methyl violet (CI 42535), ethyl violet, rhodamine B (CI145170B), malachite green (CI
42000), methylene blue (CI52015), brilliant blue, methyl green, erythricin B,
Basic fuchsin, m-cresol purple, auramine, 4-p-diethylaminophenyliminaphthoquinone, cyano-p-diethylaminophenylacetanilide, and other triphenylmethanes, diphenylmethanes, oxazines, xanthenes, iminonaphthoquinones, azomethines As an example, a system-based or anthraquinone-based dye changes from a color to a colorless or different color tone.

On the other hand, as the discoloring agent that changes from colorless to colored, leuco dyes and, for example, triphenylamine, diphenylamine, o-chloroaniline, 1, 2,
3-triphenylguanidine, naphthylamine, diaminodiphenylmethane, p, p'-bis-dimethylaminodiphenylamine, 1,2-dianilinoethylene, p,
p ', p "-tris-dimethylaminotriphenylmethane, p, p'-bis-dimethylaminodiphenylmethylimine, p, p', p" -triamino-o-methyltriphenylmethane, p, p'-bis -Dimethylaminodiphenyl-4-anilinonaphthylmethane, p, p ', p "
-Primary or secondary arylamine dyes represented by triaminotriphenylmethane. Particularly preferred are triphenylmethane dyes and diphenylmethane dyes, more preferably triphenylmethane dyes, and particularly Victoria Pure Blue BOH. The above dye is usually contained in the photosensitive composition in an amount of about 0.5 to 10% by weight, more preferably about 1 to 5% by weight.

Cyclic acid anhydrides, phenols, organic acids and higher alcohols can be added to the photosensitive composition of the present invention in order to enhance developability. The photosensitive composition of the present invention is dissolved in a solvent that dissolves the above components and applied on an aluminum plate of a support.
The solvent used here is, for example, JP-A-62-2517.
Organic solvents as described in JP-A-39 are used alone or in combination. The photosensitive composition of the present invention comprises 2
It is dissolved and dispersed at a solid content concentration of ˜50% by weight, coated on a support and dried. The coating amount of the layer of the photosensitive composition (photosensitive layer) coated on the support varies depending on the use, but generally, the weight after drying is preferably 0.3 to 4.0 g / m ^2. . The smaller the coating amount, the smaller the exposure amount for obtaining an image, but the film strength decreases. As the coating amount increases, the exposure amount is required but the photosensitive film becomes stronger. For example, when used as a printing plate, a printing plate having a high printable number (high printing durability) can be obtained. A surfactant for improving the coated surface quality can be added to the photosensitive composition of the present invention, like the positive-type photosensitive composition described above. In the production of the photosensitive printing plate of the invention, either the back coat layer on the back side or the photosensitive composition layer on the front side may be coated on the support first, or both may be coated simultaneously.

[0053]

[Matte Layer] A matte layer is provided on the surface of the photosensitive layer provided as described above in order to shorten the vacuuming time during contact exposure using a vacuum baking frame and prevent baking blur. . Specifically, a method of providing a mat layer as described in JP-A-50-125805, JP-B-57-6582, and JP-A-61-28986, and JP-B-62-62337. Examples of the method include the method of heat-fusing a solid powder as described above, but the effects of the present invention are more prominent in a PS plate having a water-soluble, alkaline-water-developer-soluble matte layer. The average diameter of the matte layer used in the present invention is preferably 100 μm or less. When the average diameter is larger than this, when the PS plates are stacked and stored, the contact area between the photosensitive layer and the back coat layer increases, and the slipperiness is improved. Deterioration and scratches are likely to occur on the surfaces of both the photosensitive layer and the back coat layer. The average height of the mat layer is preferably 10 μm or less, more preferably 2 to 8 μm. If the average height is higher than this range, it is difficult to attach fine lines and the number of highlight dots decreases, which is not preferable for tone reproduction. Average height is 2 μm
In the following, vacuum adhesion is insufficient and baking blur occurs. The coating amount of the mat layer is preferably from 5 to 200 mg / m ^2, more preferably from 20~150mg / m ^2. When the coating amount is larger than this range, the contact area between the photosensitive layer and the back coat layer increases and causes scratches, and when it is smaller than this range, the vacuum adhesion becomes insufficient.

[0054]

[Development treatment] The PS plate thus obtained is passed through a transparent original image through a carbon arc lamp, a mercury lamp, a metal halide lamp,
After being exposed to an actinic ray using a xenon lamp, a tungsten lamp, or the like as a light source, development processing is performed. As a developer used in such a developing process, a conventionally known alkaline aqueous solution can be used. For example, sodium silicate, potassium, sodium triphosphate, potassium, ammonium, dibasic sodium, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium hydrogencarbonate, potassium, Inorganic alkaline agents such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, ammonium, potassium and lithium are mentioned. Further, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Organic alkaline agents such as ethyleneimine, ethylenediamine and pyridine are also used. These alkaline agents may be used alone or in combination of two or more.

Among the above-mentioned alkaline aqueous solutions, the developing solution which can further exert the effect of the present invention is an aqueous solution containing an alkali metal silicate and having a pH of 12 or more. Aqueous solution of alkali metal silicate is silicon oxide SiO ₂ which is a component of silicate.
To the alkali metal oxide M ₂ O (generally [SiO ₂ ] / [M
₂ O]) and the concentration can be adjusted. For example, the SiO ₂ / Na ₂ O molar ratio is 1 as disclosed in JP-A-54-62004. .0-1.
5 (that is, [SiO ₂ ] / [Na ₂ O] is 1.0 to 1.5),
An aqueous solution of sodium silicate having a SiO ₂ content of 1 to 4% by weight, and [SiO ₂ ] / [M] of 0.5 to 0.75 as described in JP-B-57-7427. (That is, [SiO ₂ ]
/ [M ₂ O] is 1.0 to 1.5) and the concentration of SiO ₂ is 1 to
4% by weight and at least 20% based on the grams of total alkali metal present in the developer.
Alkali metal silicates, which are composed of and containing potassium, are preferably used.

Further, when the PS plate is developed using an automatic developing machine, an aqueous solution (replenisher) having a higher alkaline strength than the developing solution is added to the developing solution, so that the developing solution in the developing tank for a long time is added. It is known that a large number of PS plates can be processed without replacing the plate. Also in the present invention, this replenishment system is preferably applied. For example, the SiO ₂ / Na ₂ O molar ratio of the developer as disclosed in JP-A-54-62004 is 1.0 to 1.5 (that is, [SiO ₂ ] /
[Na ₂ O] is 1.0 to 1.5), and the content of SiO ₂ is 1 to
An aqueous solution of 4% by weight of sodium silicate was used, and the molar ratio of SiO ₂ / Na ₂ O was 0.5 to 1.5 continuously or intermittently depending on the throughput of the positive photosensitive lithographic printing plate. (Ie [Si
A method of adding an aqueous sodium silicate solution (replenisher) having an O ₂ ] / [Na ₂ O] of 0.5 to 1.5) to a developer, and further, JP-B-5.
[SiO ₂ ] /, which is disclosed in JP-A-7-7427.
[M] is 0.5 to 0.75 (that is, [SiO ₂ ] / [M ₂ O] is 1.
0-1.5), using a developer of an alkali metal silicate having a SiO ₂ concentration of 1 to 4% by weight, and [SiO ₂ ] / [M of the alkali metal silicate used as a replenisher. ] Is 0.25
˜0.75 (ie [SiO ₂ ] / [M ₂ O] 0.5-1.5) and both the developer and the replenisher are grams of total alkali metal present therein. A developing method consisting of containing at least 20% potassium on an atomic basis is preferably used.

When an alkali metal silicate is used as the replenishing solution, the replenishing solution becomes highly active and the replenishing amount can be reduced by reducing the molar ratio [SiO ₂ ] / [M ₂ O]. However, running costs and the amount of waste liquid are reduced, which is preferable. However, it is known that the support aluminum of the PS plate is dissolved due to high activation to produce an insoluble matter in the developing solution. Since the back coat layer of the PS plate of the present invention can suppress the elution of aluminum from the back surface of the support, it can be preferably processed even in a high activity development replenishing system. As such a highly active developer, SiO ₂
/ M ₂ O molar ratio is 0.7 to 1.5 and the concentration of SiO ₂ is 1.
It consists of an aqueous solution of 0 to 4.0% by weight of alkali metal silicate. A particularly preferred replenisher has a SiO ₂ / M ₂ O molar ratio of
It is an aqueous solution of an alkali metal silicate having a concentration of 0.3 to 1.0 and a SiO ₂ concentration of 0.5 to 4.0% by weight. More preferably, the molar ratio is 0.3 to 0.6 and the SiO ₂ concentration is 0.5 to 2.0% by weight. When the SiO ₂ / M ₂ O molar ratio of the replenisher becomes smaller than 0.3, the dissolution of the anodized film in the non-image area (the area where the photosensitive layer is removed by development) on the side having the photosensitive layer of the aluminum support becomes excessive. Therefore, the generation of insoluble matter cannot be suppressed. On the other hand, if the molar ratio is 1.0 or more, the activity of the replenisher is poor and a large replenishment amount is required, which is not suitable for the purpose of the present invention. Further, when the SiO ₂ concentration is 0.5% by weight or less, insoluble matter is likely to be formed, and when the SiO ₂ concentration is 4.0% by weight or more, a large amount of silica gel is generated during the neutralization treatment of the used waste liquid, which is not preferable. The developer and replenisher used in the development of the positive and negative PS plates of the present invention may contain, if necessary, for the purpose of promoting or suppressing the developability, dispersing the development residue and improving the ink affinity of the printing plate image area. Various surfactants and organic solvents can be added. Preferred surfactants include anionic, cationic, nonionic and amphoteric surfactants. Preferable examples of the surfactant include all the surfactants exemplified as the surfactant used for the back coat layer, but the organic boron surfactant described in JP-B-1-57895 is particularly preferable. preferable. The above surfactants can be used alone or in combination of two or more, and are added to the developer in an amount of 0.001 to 10% by weight, more preferably 0.01 to 5% by weight.

Suitable organic solvents are those having a solubility in water of about 10% by weight or less, preferably 5% by weight or less. For example, 1-phenylethanol, 2-phenylethanol, 3-phenyl-1-propanol, 4-phenyl-1-butanol, 4-phenyl-2-butanol, 2-phenyl-1.
-Butanol, 2-phenoxyethanol, 2-benzyloxyethanol, o-methoxybenzyl alcohol, m-methoxybenzyl alcohol, p-methoxybenzyl alcohol, benzyl alcohol, cyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol and 4 -Methylcyclohexanol, N-phenylethanolamine, N-phenyldiethanolamine and the like can be mentioned. The content of the organic solvent is 0.1 to 5% by weight based on the total weight of the used liquid. The amount used is closely related to the amount used of the surfactant, and it is preferable to increase the amount of the surfactant as the amount of the organic solvent increases. This is because when the amount of the surfactant is small and the amount of the organic solvent is large, the organic solvent is not completely dissolved, and it is therefore impossible to expect to secure good developability.

A reducing agent is further added to the developer and replenisher used for developing the PS plate of the present invention. This is to prevent stains on the printing plate and is particularly effective when developing a negative PS plate containing a photosensitive diazonium salt compound. Preferable organic reducing agents include phenol compounds such as thiosalicylic acid, hydroquinone, methole, methoxyquinone, resorcin, and 2-methylresorcin, and amine compounds such as phenylenediamine and phenylhydrazine. More preferable inorganic reducing agents include sodium salts, potassium salts, and ammonium salts of inorganic acids such as sulfurous acid, bisulfite acid, phosphorous acid, hydrogen phosphite, dihydrogen phosphite, thiosulfuric acid and dithionous acid. Examples thereof include salt. Among these reducing agents, sulfite has a particularly excellent antifouling effect. These reducing agents are preferably added to the developer at the time of use in an amount of 0.0
It is contained in the range of 5 to 5% by weight.

An organic carboxylic acid may be further added to the developing solution and the replenishing solution. Preferred organic carboxylic acids are aliphatic carboxylic acids having 6 to 20 carbon atoms and aromatic carboxylic acids. Specific examples of the aliphatic carboxylic acid include caproic acid, enanthic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid and the like, and particularly preferred is an alkanoic acid having 8 to 12 carbon atoms. .. Further, it may be an unsaturated fatty acid having a double bond in the carbon chain or a branched carbon chain. The aromatic carboxylic acid is a compound in which a benzene ring, a naphthalene ring, an anthracene ring or the like is substituted with a carboxyl group, and specifically, o-chlorobenzoic acid, p-chlorobenzoic acid,
o-hydroxybenzoic acid, p-hydroxybenzoic acid, o
-Aminobenzoic acid, p-aminobenzoic acid, 2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic acid,
2,6-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-
Although there are naphthoic acid and 2-naphthoic acid, hydroxynaphthoic acid is particularly effective. The aliphatic and aromatic carboxylic acids are preferably used in the form of sodium salt, potassium salt or ammonium salt in order to enhance water solubility.
The content of the organic carboxylic acid in the developer used in the present invention is not particularly limited, but if it is less than 0.1% by weight, the effect is not sufficient, and if it is 10% by weight or more, further improvement of the effect cannot be achieved. Not only that, when other additives are used in combination, dissolution may be hindered. Therefore, the preferable addition amount is 0.1 to 10% by weight with respect to the developing solution at the time of use, and more preferably 0.1.
It is 5 to 4% by weight.

If necessary, the developer and replenisher may further contain conventionally known compounds such as defoaming agents and water softeners. Examples of the water softener include polyphosphoric acid and its sodium salt, potassium salt and ammonium salt, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid, 1,2-diaminocyclohexane. Aminopolycarboxylic acids such as tetraacetic acid and 1,3-diamino-2-propanoltetraacetic acid and their sodium, potassium and ammonium salts,
Aminotri (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), diethylenetriaminepenta (methylenephosphonic acid), triethylenetetraminehexa (methylenephosphonic acid), hydroxyethylethylenediaminetri (methylenephosphonic acid) and 1-
Examples thereof include hydroxyethane-1,1-diphosphonic acid and their sodium, potassium and ammonium salts.

The optimum value of such a water softener varies depending on its chelating power, the hardness of the hard water used and the amount of hard water. 0.01-5% by weight, more preferably 0.01-
It is in the range of 0.5% by weight. If the addition amount is less than this range, the intended purpose is not sufficiently achieved, and if the addition amount is more than this range, the image area is adversely affected such as color loss. The remaining component of the developing solution and the replenishing solution is water, but if desired, various additives known in the art can be added. It is advantageous in terms of transportation that the developing solution and the replenishing solution are concentrated solutions having a water content smaller than that at the time of use and are diluted with water at the time of use. In this case, the degree of enrichment should be such that each component does not separate or precipitate.

In the developing method of the present invention, the components in the developer consumed by processing the PS plate, the developer carried out by adhering to the processed PS plate and / or carbon dioxide gas in the air. A replenisher solution is added in an amount to compensate the alkaline component in the developer solution neutralized by. For example, when the PS plate is developed by an automatic developing machine which is processed while being conveyed by rollers, as described in British Patent No. 2046931, an amount proportional to the length of the PS plate to be processed in the carrying direction. The method of adding the replenisher, the method of adding the replenisher in an amount proportional to the area of the SP plate to be treated,
Alternatively, a method of intermittently adding a replenisher in an amount proportional to the time during which the developer circulating pump of the automatic processor is operating is advantageous in addition to these additions. Also, U.S. Pat.
A method in which the electric conductivity or impedance of the developing solution is measured and a replenishing solution is added according to the value as described in 2,246 and European Patent No. 107454 is also a preferable method. Whatever the means of adding the replenisher, by developing the positive PS plate, and / or
Alternatively, replenisher is added to compensate for changes in the components of the developer over time and / or to supplement the amount of developer carried with the developed PS plate.

The PS plates developed in this manner are disclosed in JP-A-54-8002, JP-A-55-115045 and JP-A-5-15045.
As described in each publication such as 9-58431,
It is post-treated with washing water, a rinse solution containing a surfactant and the like, and a desensitizing solution containing gum arabic and a starch derivative. Various combinations of these treatments can be used for the post-treatment of the PS plate of the present invention. In recent years, in the plate making / printing industry, automatic developing machines for PS plates have been widely used in order to rationalize and standardize the plate making work. This automatic developing machine generally comprises a developing section and a post-processing section, and is an apparatus for conveying a PS plate,
Exposed P consisting of each processing liquid tank and spray device
While the S plate is conveyed horizontally, each processing solution pumped up by a pump is sprayed from a spray nozzle for development processing. Recently, there is also known a method in which a PS plate is dipped and conveyed by a submerged guide roll or the like in a processing liquid tank filled with the processing liquid, and such a processing is disclosed in Japanese Patent Laid-Open No. HEI-2.
It is preferable to use an automatic developing machine as described in each of the publications of -7054 and 2-32357. In such automatic processing, it is possible to perform processing while supplementing each processing solution with a replenishing solution according to the processing amount, operating time, and the like. Further, a so-called disposable processing method of processing with a substantially unused processing liquid can be applied. The lithographic printing plate obtained by such treatment is placed on an offset printing machine,
Used for printing many sheets.

[0065]

The present invention will be described in detail with reference to the following examples.

Example 1, Comparative Examples 1 to 3 An aluminum plate having a thickness of 0.30 mm was grained on its surface using a nylon brush and an aqueous suspension of 400 mesh pumice, and then washed thoroughly with water. It was immersed in 10% sodium hydroxide at 70 ° C. for 60 seconds for etching, washed with running water, neutralized with 20% NHO ₃ and washed with water. This was subjected to a sine wave alternating current under the condition of V _A = 12.7 V in a 1% nitric acid aqueous solution for 16 times.
The electrolytic surface roughening treatment was carried out with the amount of electricity at the anode of 0 coulomb / dm ² . The surface roughness was measured and found to be 0.6 μ (Ra indication). Then, after soaking in 30% H ₂ SO ₄ aqueous solution and desmutting at 55 ° C for 2 minutes, 20% H ₂ SO ₄ was added.
A cathode was placed on the grained surface in an aqueous solution, and anodized to a thickness of 2.7 g / m ² at a current density of 2 A / dm ² to prepare a substrate. The anodized film on the back surface at this time was about 0.2 g / m ² at the center of the aluminum plate and about 0.5 g / m ² at the ends. The back surface of the substrate thus treated was coated with the following sol-gel reaction solution with a bar coater and dried at 100 ° C. for 1 minute, and the coating amount after drying was 50 mg / m ²
A support A provided with the back coat layer of was prepared.

Sol-gel reaction solution Tetraethyl silicate 50 parts by weight Water 20 〃 Methanol 10 〃 Phosphoric acid 0.07 〃 When the above components were mixed and stirred, an exothermic reaction started in about 5 minutes. After reacting for 30 minutes, the following solution was added to prepare a back coat coating solution. Pyrogallol formaldehyde condensation resin (MW 2000) 4 parts by weight Dimethyl phthalate 5 〃 Methanol 1000 〃

For comparison, a support B was prepared by preparing a back coat coating solution containing 1000 parts by weight of methanol after the reaction for 30 minutes, coating and drying. For comparison, a saturated copolyester resin (trade name Chemit K-12
94) An organic polymer compound obtained by dissolving 3.5 parts by weight of methyl ethyl ketone in 100 parts by weight and further dissolving 0.05 parts by weight of Megafac F-176 (a fluorine-based surfactant manufactured by Dainippon Ink and Chemicals, Inc.). A backcoat coating solution consisting of only the above was prepared, coated and dried to prepare a support C. A support having no back coat layer on its back surface was designated as D.
Subsequently, the following photosensitive solutions were coated on the surfaces of the supports A, B, C and D so that the coating amount after drying was 2.5 g / m ² .

Photosensitive solution Esterified product of 1,2-diazonaphthoquinone-5-sulfonyl chloride and pyrogallol-acetone resin (described in Example 1 of US Pat. No. 3,635,709) 45 parts by weight Cresol formaldehyde novolac Resin 110 parts by weight 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine 2 parts by weight Oil Blue # 603 (Orient Chemical Co., Ltd. 1 part by weight) Megafac F-177 (Dainippon Ink and Chemicals, Inc. Fluorine-based interface 0.4 parts by weight Activator) Methyl ethyl ketone 100 parts by weight Propylene glycol monomethyl ether 100 parts by weight

The four types of PS plates thus obtained were
It was cut into 1030 mm x 800 mm and 50 sheets were prepared for each. This 50
After stacking the sheets, one sheet of cardboard having a thickness of about 0.5 mm was placed on each of the upper and lower sides, and the four corners were taped to each other, and then wrapped with aluminum kraft paper. This was further packaged in a cardboard case, taped, and then subjected to a transportation test by a truck. The results of the presence or absence of scratches after transportation are shown in Table 1. Next, prepare a large number of 4 types of PS plates, each cut into a size of 1030 mm x 800 mm, and pass them through the manuscript film from a distance of 1 m to 3
It was exposed for 60 seconds using a KW metal halide lamp.

Commercially available automatic developing machine P having an immersion type developing tank
In the developing tank of S-900D (manufactured by Fuji Photo Film Co., Ltd.), [SiO ₂ ] / [M ₂ O] ratio 1.2, SiO ₂ concentration (wt%) 1.
5 potassium silicate aqueous solution, N-alkyl-
N, N-dihydroxyethyl betaine amphoteric surfactant
A developing solution containing 0.04% by weight was charged, and the above-described four types of exposed photosensitive lithographic printing plates were separately processed at 100 plates per day for 1 month. During this period, PS plate treatment and reduction of the developer activity due to carbon dioxide in the air
-Detected with the conductivity sensor built into the 900D,
Computer feedback system, [SiO ₂ ]
/ [M ₂ O] ratio of 0.8 and SiO ₂ concentration (wt%) of 1.9 in potassium silicate aqueous solution, and N-alkyl-N, N-dihydroxyethyl betaine amphoteric surfactant is 0.04 wt%. The activity of the developer was kept constant by replenishing the developer replenisher contained therein. To check the activity, use a step tablet (15 steps with an optical density difference of 0.15 for 15 steps) to gradually change the light intensity and develop the image printed on the PS plate. It was performed by reading the number of steps of the remaining image corresponding to, and comparing with the number of steps at the start of the process. After one month, the presence or absence of insoluble matter deposited on the bottom of the developing tank when the developing solution was removed from the developing tank is shown in Table 1. No insoluble matter was observed in PS plates A, B, and C, which were provided with a back coat layer on the back surface and were treated with silicate. However, not only the insoluble matter was deposited in the developing tank treated with the untreated PS plate D, but also troubles such as clogging of the spray and filter and adhesion of white precipitate to the roller occurred. Next, in order to store the developed PS plate,
Developing ink PI-2 (emulsion type ink manufactured by Fuji Photo Film Co., Ltd.) was applied onto the plate using a sponge. Rinse with water to remove the ink on the non-image area, and protect gum G
U-7 (manufactured by Fuji Photo Film Co., Ltd.) was diluted twice with water, and a gum solution was applied with a sponge and dried.

When the printing plates thus prepared were piled up and stored, it was found that there was ink adhered to the back surface and that there was no ink adhering to the back surface. This deposited ink was also transferred to the surface and significantly deteriorated the plate inspection property of the printing plate. Table 1 shows the presence or absence of ink adhesion. Then, as a simulation test to confirm the manufacturing suitability, the coating solution for the back coat layer was intentionally dropped on the polished surface of the stainless steel 316 material and dried to dryness. After 3 days, the organic solvent was methanol / methyl ethyl ketone (1/1). I investigated whether it could be removed by rubbing. The results are shown in Table 1. In addition, as a simulation test to confirm the suitability for manufacturing, a backcoat solution was dropped on a mirror-finished surface of stainless 304 material, and after one week, it was peeled into scales, and it was checked whether or not it was easily scattered as fine powder. It was
The results are shown in Table 1. The PS plate A had no problems in production, could be stably processed in a large amount for a long period of time, and was not easily scratched on the photosensitive layer without interleaving paper. Further, no adhesion of developing ink or the like was found on the back surface.

[0072]

[Table 1] ─────────────────────────────────── Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 PS version ABCD ──────────────────────────────────── Scratches on the photosensitive layer during transportation A B AC Insoluble matter generation in developing tank A A A C ^* Presence or absence of ink on back surface (PI-2) A A A A A Adhesion of dry solids Removability of organic solids with A CA A- Dry Exfoliation of scale-like exfoliation of solid matter AC A- ─────────────────────────────────── A : None or good, B: Almost none or almost good, C: Some or bad,
D: Many or extremely poor * Clogged spray or filter

[0073]

Example 2, Comparative Examples 4, 5 and 6 An aluminum plate having a thickness of 0.24 mm was grained on its surface using a nylon brush and a 400 mesh pumicetone-water suspension, and then thoroughly washed with water. After being immersed in 10% sodium hydroxide at 70 ° C. for 20 seconds for etching, it was washed with running water, and then 2
It was neutralized and washed with 0% NHO ₃ . This is V _A = 12.7V
Electrolytic surface roughening treatment was carried out in a 0.7% aqueous solution of nitric acid under an electric current of 400 coulomb / dm ² using a sinusoidal alternating waveform current under the condition of. This substrate was treated in a 10% aqueous sodium hydroxide solution so that the amount of aluminum dissolved on the surface would be 0.9 g / m ² . After washing with water, neutralization in a 20% nitric acid solution, washing to remove smut, and then in an 18% H ₂ SO ₄ aqueous solution, the cathode was made to face the grained surface and the amount of oxide film was 2 g / m ²
Was anodized. This is washed with water and dried to obtain the substrate E
Got At this time, the amount of oxide film on the back surface is 0.2 to 0.4 g / m ²
Met. The sol-gel reaction solution described below was applied to the back surface of the substrate thus treated with a bar coater, and the temperature was maintained at 100 ° C. for 3 hours.
After drying for 0 seconds, a substrate F provided with a back coat layer having a coating amount after drying of 80 mg / m ² was prepared.

Sol-gel reaction solution Tetraethyl silicate 50 parts by weight Water 80 〃 Methanol 10 〃 Phosphoric acid 0.1 〃 When the above components were mixed and stirred, heat was generated in about 45 minutes. 6
A backcoat liquid was prepared by stirring for 0 minutes to cause a reaction, and then adding the following liquids. Resorcinol-formaldehyde condensation resin 5 parts by weight dibutyl maleate 5 〃 methanol 900 〃 Further, as a comparison, a substrate G was prepared by coating and drying a back coat solution containing 800 parts by weight of methanol after reacting by stirring for 60 minutes. . Next, a photosensitive solution having the following composition was prepared, and a photosensitive layer was provided on each of the substrates E, F, and G so that the weight after drying was 2 g / m ² .

Photosensitive Solution Esterified product of 1,2-diazonaphthoquinone-5-sulfonyl chloride and pyrogallol-acetone resin (described in Example 1 of US Pat. No. 3,635,709) 76 parts by weight Cresol formaldehyde novolac Resin 190 parts by weight Phthalic anhydride 20 parts by weight 4- [p-N- (p-hydroxybenzoyl) aminophenyl] -2,6-bis (trichloromethyl) -s-triazine 2 parts by weight Victoria Pure Blue BOH (Hodogaya Chemical Industry Co., Ltd. 3 parts by weight Megafac F-177 (Dainippon Ink and Chemicals Co., Ltd. fluorine interface 0.6 parts by weight Activator) Methyl ethyl ketone 1500 parts by weight Propylene glycol monomethyl ether 1500 parts by weight

Next, the PS plates E, F and G were 1003 mm × 8.
A large number of pieces cut into a size of 00 mm were prepared, and these were exposed through a document film for 60 seconds using a metal halide lamp of 3 kw from a distance of 1 m. Next, in a developing tank of a commercial automatic developing machine PS-900D (manufactured by Fuji Photo Film Co., Ltd.) having an immersion developing tank, an aqueous potassium silicate solution having the composition shown in Table 2 and N-alkyl-N, N-dihydroxyethyl were used. A betaine amphoteric surfactant was charged in a developing solution of 0.04% by weight, and the exposed PS plates E, F and G were subjected to running treatment for 100 plates per day for one month. During this period, the processing of the PS plate and the decrease in the activity of the developing solution due to carbon dioxide in the air were detected by the conductivity sensor built into the PS-900D, and the replenisher solutions shown in Table 2 were fed back by the computer. The activity of the developer was kept constant by replenishing.
The activity was checked in the same manner as in Example 1. Further, in the same manner as in Example 1, a test for scratches on the photosensitive layer by transportation, a PS plate backside ink adhesion test with a PI-2 ink deposit, removability of the dried solid matter with an organic solvent, scale-like peeling of the dried solid matter It was also carried out with or without. The results are shown in Table 2.

[0077]

[Table 2] ─────────────────────────────────── Example 2 Comparative Example 4 Comparative Example 5 Comparative Example 6 PS version F G E E ──────────────────────────────────── Developer composition [SiO ₂ ] / [K ₂ O] ratio 1.2 1.2 1.2 1.2 1.2 SiO ₂ (wt%) 1.4 1.4 1.4 1.4 Replenisher composition [SiO ₂ ] / [K ₂ O] ratio 0.72 0.72 0.72 1.2 SiO ₂ (wt%) 1.80 1.80 1.80 3.0 ───────────────────── ─────────────── Treatment performance Running 40 40 40 80 Average replenishment rate (cc / m ² ) Running ± 0.5 steps ± 0.5 steps ± 3 steps ± 0. 5 steps Sensitivity fluctuation Insoluble matter in developing tank None None Many Occurrence of small amount (spray clogging large) ────────────────────────── ────────── Performance A B C C scuff on the photosensitive layer during transportation A A A A A of ink on the back side Adhesion ───────────────── ──────────────────── Manufacture suitability Removability of dry solids with organic solvent AC ---- Scale of dry solids AC-- Existence ───────────────────────────────────

Table 2 shows the composition of the replenisher used and the result of the running treatment. In the PS plate provided with the back coat layer of the present invention, the replenisher replenishment amount is about 1/2,
Moreover, no insoluble matter was generated, and stable treatment was possible. On the other hand, in the conventional method (Comparative Example 6), the trouble caused by the insoluble matter was slight, but not only the replenishment amount was large and the running cost was high, but a large amount of waste liquid treatment was required. In addition, although the replenishment amount can be reduced by increasing the activity of the replenisher as in Comparative Example 5, problems such as stains on the printing plate due to insoluble matter, clogging of sprays and filters, and adherence of white deposits to the roller may occur. Occurred and the sensitivity was not stable.
In addition, Comparative Example 4 was as stable as Example 2 in terms of processing stability, but was not sufficient due to problems such as suitability in production and scratches during transportation.

[0079]

Example 3 An aluminum plate having a thickness of 0.2 mm was grained on its surface (one side) using a nylon brush and an aqueous suspension of 400 mesh pumice, and then thoroughly washed with water. After immersion in 10% sodium hydroxide at 70 ° C. for 60 seconds for etching, and then rinsing with running water, V _A = 12.
An electrolytic surface roughening treatment was performed on the grained surface in an aqueous 1% nitric acid solution at an anode electricity of 160 coulomb / dm ² using a sinusoidal alternating waveform current under the condition of 7V. Then, it was immersed in a 30% sulfuric acid aqueous solution and desmutted at 55 ° C for 2 minutes, and then a current density of 2% was applied in a 20% sulfuric acid aqueous solution.
Anodization was performed at A / dm ^{2 so} that the thickness of the oxide film on the electrolytically roughened surface was 2.7 g / m ² . At this time, the amount of the anodized film on the back surface was 0.2 to 0.5 g / m ² . Then, it was immersed in a 2% aqueous solution of sodium silicate No. 3 at 70 ° C. for hydrophilic treatment. A sol-gel reaction solution was applied to the back surface of the substrate thus treated in the same manner as in Example 2 to form a back coat layer. The surface of this substrate is coated with the following photosensitive solution, and the coating amount after drying is 1.7 g.
The photosensitive layer was provided so as to be / m ² .

Photosensitive solution Hexafluorophosphate salt of condensate of p-diazodiphenylamine and paraformaldehyde 0.12 parts by weight 2-hydroxyethyl methacrylate copolymer (synthesized by the method of Example 1 of British Patent No. 1,505,739) 2.0 parts by weight Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Industry Co., Ltd.) 0.03 parts by weight Megafac F-177 (Dainippon Ink and Chemicals Co., Ltd. fluorine interface 0.006 parts by weight Activator) 2-methoxyethanol 15 parts by weight Methanol 10 parts by weight Ethylene chloride 5 parts by weight The negative PS plate thus obtained was examined for scratches by a mass transport test in the same manner as in Example 1, but a problem was observed. Furthermore, there was no problem in manufacturing the back coat layer.

[0081]

Example 4 In exactly the same manner as in Example 3, an aluminum substrate having a grained surface and a back coat layer on the back surface was obtained. Next, the following sensitizing solution was prepared, coated on a grained surface so that the weight after drying was 1.5 g / m ^2, and dried to obtain a negative PS plate. Photosensitive solution Methyl methacrylate / N- [6- (methacryloyloxy) hexyl] -2,3-dimethylmaleimide / methacrylic acid = 10/60/30 (molar ratio) copolymer [Mw = 3.5 × 10 ⁴ ( GPC), Tg = about 40 ° C. (DSC)] 5 parts by weight 3-ethoxycarbonyl-7-methyl-thioxanthone 0.30 parts by weight Dodecyl benzene sulfonate of formaldehyde co-condensate of 4-diazodiphenylamine and phenoxyacetic acid 0.20 parts by weight Propylene glycol monomethyl ether 50 parts by weight Methyl ethyl ketone 50 parts by weight Megafac F-177 (Dainippon Ink and Chemicals, Inc., fluorine-based nonionic surfactant) 0.03 parts by weight Victoria Pure Blue BOH ( Hodogaya Chemical Co., Ltd.) 0.10 parts by weight

The negative PS plate thus obtained was
Contact exposure was performed through a negative film. The exposure was performed by irradiating a 2 Kw ultra-high pressure mercury lamp for 60 seconds. Then, [SiO ₂ ] / [K ₂ O used as a replenisher in Example 2
], And a potassium silicate aqueous solution having a molar ratio of 0.72 was used as a developing solution at 25 ° C. for 30 seconds. After washing with water, a gum solution was applied and printing was performed with a KORD printing machine, and as a result, 50,000 sheets of printed matter having no stain on the non-image area were obtained. Next, a large number of the same negative PS plates were prepared, and in the same manner as in Example 1,
A transportation test was conducted, but no problem of scratches occurred.

[0083]

[Example 5] In exactly the same manner as in Example 1, a grain-polished surface and anodized substrate was produced. Apply the following sol-gel reaction diluent on the backside of the substrate with a bar coater,
Dry at 100 ° C for 1 minute and the coating amount after drying is 60mg / m ²
Was provided with a back coat layer. Sol-gel reaction solution Tetraethyl silicate 50 parts by weight Water 86.4 parts by weight Methanol 10.8 parts by weight Phosphoric acid (85%) 0.08 parts by weight When the above components were mixed and stirred, heat was generated in about 45 minutes. The mixture was stirred for another 60 minutes to react, and then mixed with the following diluent to prepare a back coat coating solution. Diluent Phenol-formaldehyde resin 3.5 parts by weight (MW 3000) dibutyl phthalate 5.0 parts by weight Methanol 800 parts by weight Propylene glycol monomethyl ether 270 parts by weight Then, a photosensitive layer was formed on the surface of the substrate in the same manner as in Example 1. Was provided to prepare a positive PS plate. The back coat layer of the PS plate thus obtained was highly flexible and did not crack. When evaluated in the same manner as in Example 1, the same performance as PS plate A was exhibited.

[0084]

INDUSTRIAL APPLICABILITY According to the photosensitive lithographic printing plate and the plate-making method of the present invention, the replenishment amount of the developing solution can be reduced, and insoluble matter can be generated even if a large amount of the photosensitive lithographic printing plate is processed for a long period of time. Stable processing can be performed without generation. Furthermore, even when a large number of photosensitive lithographic printing plates are piled up and conveyed, the photosensitive layer side is not scratched. Furthermore, the photosensitive lithographic printing plate of the present invention does not have a defect that a lipophilic substance such as developing ink adheres to the back surface to stain it. Furthermore, the photosensitive lithographic printing plate of the present invention can be stably produced in large quantities.

Claims (3)

[Claims] 1. An aluminum support having an anodized film on both sides has a photosensitive layer on one side, and an organic metal compound or an inorganic metal compound is hydrolyzed and polycondensed on the side opposite to the photosensitive layer. A photosensitive lithographic printing plate comprising a coating layer containing the obtained metal oxide, an organic polymer compound and a plasticizer. 2. A method for producing a lithographic printing plate, which comprises subjecting the photosensitive lithographic printing plate according to claim 1 to imagewise exposure and developing with an alkaline aqueous solution containing an alkali metal silicate and having a pH of 12 or more. 3. Compensation for changes in the developing solution due to development by adding a replenishing solution comprising an aqueous solution of an alkali metal silicate to the developing solution, and
O ₂ ] / [M ₂ O] ratio (where [SiO ₂ ] is the molar concentration of SiO ₂ (mol / l), [M ₂ O] is the oxide M ₂ O of alkali metal M)
Is an aqueous solution of an alkali metal silicate having a SiO ₂ content of 0.5 to 4.0% by weight, and a SiO ₂ content of 0.5 to 4.0% by weight. The method for producing a lithographic printing plate according to claim 2.