JP3442875B2 - Photosensitive lithographic printing plate - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a photosensitive lithographic printing plate. More specifically, the present invention relates to a photosensitive lithographic printing plate capable of obtaining a lithographic printing plate that is free from stains on its edges.

[0002]

2. Description of the Related Art Photosensitive lithographic printing plates having an aluminum plate as a support are commercially available and widely used. As a method for producing such a photosensitive lithographic printing plate, generally, a sheet-shaped or coil-shaped aluminum plate is subjected to various surface treatments such as graining, anodic oxidation and chemical conversion treatment, individually or in combination, and then a photosensitive solution is applied. A method of drying and cutting into a desired size is adopted. When such a photosensitive lithographic printing plate is printed using a printing plate obtained by subjecting it to image exposure and development, it is printed on a paper smaller than the size of the printing plate such as a normal sheet-fed printing press. If you do, there is no problem of the end because the part corresponding to the end of the printing plate does not become the printing surface, but when printing continuously on roll paper using a rotary press such as newspaper printing, Since the end portion of the printing plate also comes into contact with the roll paper and becomes the printing surface, the ink adhering to the end portion is also printed on the paper and stains, greatly impairing the commercial value of the printed matter. As a method for preventing the edge portion of the printing plate from being soiled, for example, Japanese Patent Publication No. 57-46754 discloses a method of cutting the end surface of an aluminum support so as to be 10 to 45 degrees with respect to the aluminum surface. However, when 10,000 or more sheets are printed, ink accumulates on the edges and stains occur. Also, Japanese Patent Publication No. 62-61946 discloses a method of desensitizing the end surface of an aluminum support.
JP-A-256495 discloses a method in which an end surface of a printing plate of an aluminum support is preliminarily made hydrophilic, but it is still insufficient, and further improvement has been desired.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved photosensitive lithographic printing plate capable of obtaining a lithographic printing plate free from stains on its edges.

[0004]

The above object of the present invention is to provide a photosensitive lithographic printing plate in which a photosensitive layer is provided on an aluminum support having a hydrophilic surface, on two opposite sides of the aluminum support or This can be achieved by a photosensitive lithographic printing plate characterized in that the end portions of four sides are curved to the lower surface side, and the curved side surface of the photosensitive layer surface is subjected to desensitizing treatment. Such a photosensitive printing plate, for example, after providing a photosensitive layer on an aluminum support having a hydrophilic surface,
It can be manufactured by curving the ends of two or four opposite sides of the aluminum support to the lower surface side and cutting, and then desensitizing the side surface of the photosensitive layer surface.
Specifically, the coiled aluminum plate is degreased and washed by various methods, grained by various methods, and then the residue is removed if necessary, and anodizing treatment and hydrophilic treatment are performed,
Apply the photosensitive solution and dry. After that, when slitting to a size suitable for a desired printing machine (corresponding to the end surface of the aluminum support that contacts the paper at the time of printing), the end portion is curved to the lower surface side, and the photosensitive lithographic printing plate of the present invention is Form the edges. More specifically, the slitting device of FIG. 1 and the lower cutting blades of FIGS. 2 and 4 are used for cutting, and the end portions as shown in FIGS. 3 and 5 are curved to the lower surface side. To form.

FIG. 1 is a sectional view showing a cutting portion of a slitter device. The slitter device includes a pair of upper and lower cutting blades 10,
20 are arranged on the left and right. These cutting blades 10, 2
0 is a disc-shaped round blade, and the upper cutting blades 10a and 10
b is coaxially supported by the rotary shaft 11, and the lower cutting blades 20a and 20b are coaxially supported by the rotary shaft 21, respectively. And
Upper cutting blades 10a, 10b and lower cutting blades 20a, 20b
And are rotated in opposite directions. The aluminum sheet 30 includes the upper cutting blades 10a and 10b and the lower cutting blade 20.
It is passed between a and 20b and cut into a predetermined width. FIG. 2 shows a first embodiment of the shape of the tip of the lower cutting blade of the present invention. The lower cutting blade 20 is chamfered so as to scrape X on the side surface and Y on the outer peripheral surface side. The aluminum sheet 30 cut by using the chamfered lower cutting blade 20 has an end portion 30 as shown in FIG.
a has a curved shape on the lower surface side.

FIG. 4 shows a second embodiment of the shape of the tip of the lower cutting blade. The lower cutting blade 25 has a step formed by notching only X on the side surface side and Y on the outer peripheral surface side. As shown in FIG. 5, the aluminum sheet 35 cut by using the lower cutting blade 25 having the stepped shape has its end portion 35a curved to the lower surface side and the end of the lower side surface of the curved portion 35a. A flat portion 35b is formed on the portion. The preferable range of X in FIGS. 3 and 5 is 10 to 200 μm, and more preferably 30 to 200 μm. 3 and 5
The preferred range of Y is 20 to 3000 μm, more preferably 50 to 3000 μm. The X / Y ratio is preferably 1/2 or less. The preferable range of Z in FIG. 5 is 5 to 2000 μm, more preferably 20 to 2000 μm, although it depends on the size of Y. When X in FIGS. 3 and 5 is less than 10 μm and Y is less than 20 μm, the edges are contaminated. When X in FIGS. 3 and 5 is larger than 200 μm, conveyance failure is likely to occur in the automatic plate making machine.
When Y in FIGS. 3 and 5 is larger than 3000 μm, the printing durability of the image area near the edge is deteriorated. When X / Y is larger than 1/2, stains occur near the curved portion. Z in FIG.
Is less than 5 μm, stains may occur at the edges under printing conditions in which the amount of dampening water is reduced and the amount of ink is increased.
On the other hand, when Z is larger than 2000 μm, the ink density of the image area near the edge is lowered.

Surprisingly, the edge of the photosensitive lithographic printing plate is greatly decontaminated by forming the edge on the lower surface side in a curved shape and then desensitizing the side surface of the photosensitive layer. Was improved. As the desensitizing solution used in this desensitizing treatment, the desensitizing liquid used in the desensitizing treatment of a lithographic printing plate having an aluminum plate as a support can be effectively used. Examples of the preferable desensitizing solution include an aqueous solution containing at least one kind of hydrophilic organic polymer compound, hexametaphosphoric acid and its salt, and phytic acid and its salt. Specific hydrophilic organic polymer compounds include gum arabic, dextrins, alginates such as sodium alginate, water-soluble celluloses such as carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, and polyacrylamide. , A water-soluble copolymer containing an acrylamide unit, polyacrylic acid, a copolymer containing an acrylic acid unit, polyacrylic acid, a copolymer containing an acrylic acid unit, polymethacrylic acid, a copolymer containing a methacrylic acid unit, Examples thereof include copolymers of vinyl methyl ether and maleic anhydride, copolymers of vinyl acetate and maleic anhydride, and phosphoric acid-modified starch. Among them, gum arabic is preferable because it has a strong desensitizing effect. These hydrophilic polymer compounds can be used in combination of two or more, if necessary,
It is used at a concentration of about 1-40% by weight, more preferably 3-30% by weight.

Specific examples of hexametaphosphate include alkali metal hexametaphosphate or ammonium salt. Examples of the alkali metal hexametaphosphate or ammonium hexametaphosphate include sodium hexametaphosphate, potassium hexametaphosphate, and ammonium hexametaphosphate. Specific examples of phytic acid or a salt thereof include alkali metal salts such as sodium salt, potassium salt, lithium salt, ammonium salt, amine salt and the like. Examples of amine salts include diethylamine, triethylamine, n-propylamine, di-n-propylamine,
Tri-n-propylamine, n-butylamine, n-amylamine, n-hexylamine, laurylamine, ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, ethanolamine, diethanolamine, triethanolamine, Examples thereof include salts of allylamine and aniline. The phytate may be a normal salt obtained by substituting all the hydrogen atoms of 12 acids, or a hydrogen salt (acid salt) obtained by substituting a part of hydrogen atoms of the acid, or a simple salt consisting of a salt of one kind of base. Any form of double salt containing at least one kind of base as a component can be used. These compounds can be used alone or in combination of two or more kinds.

The desensitizing solution used in the present invention preferably further contains a metal salt of a strong acid, whereby the desensitizing action can be enhanced. Specific examples of the metal salt of strong acid include sodium salt, potassium salt of nitric acid,
Magnesium salt, calcium salt and zinc salt, sodium salt of sulfuric acid, potassium salt, magnesium salt, calcium salt and zinc salt, sodium salt of chromic acid, potassium salt, magnesium salt, calcium salt and zinc salt, and sodium fluoride and fluoride salt. Examples thereof include potassium iodide.
These strong acid metal salts can be used in combination of two or more kinds, and the amount thereof is approximately based on the total weight of the desensitizing solution.
0.01 to 5% by weight is preferable. The pH value of the desensitizing solution used in the present invention is adjusted to an acidic range, more preferably 1 to 5, and most preferably 1.5 to 4.5. Therefore, more acid is added to the aqueous phase if the pH of the aqueous phase is not acidic. Examples of the acid added as the pH adjusting agent include mineral acids such as phosphoric acid, sulfuric acid and nitric acid, such as citric acid, tannic acid, malic acid, glacial acetic acid, lactic acid, oxalic acid, p-toluenesulfonic acid and organic phosphonic acid. Examples thereof include organic acids. Among them, phosphoric acid is particularly excellent because it not only functions as a pH adjuster but also has the effect of strengthening the desensitizing action, and 0.01 to 20% by weight based on the total weight of the desensitizing solution, Most preferably, it is contained in the range of 0.1 to 10% by weight.

The desensitizing solution used in the present invention preferably contains a wetting agent and / or a surfactant, which can improve the coating property of the desensitizing solution. As a specific wetting agent, a lower polyhydric alcohol is preferable, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, pentanediol, hexylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene. Examples thereof include glycol, glycerin, sorbitol, pentaerythritol and the like, and glycerin is particularly preferable. Examples of the surfactant include nonionic surfactants such as polyoxyethylene alkylphenyl ether and polyoxyethylene polyoxypropylene block copolymer, for example, fatty acid salts, alkyl sulfate ester hydrochloric acid, alkylbenzene sulfonates, alkylnaphthalene sulfonates. Anionic surfactants such as dialkylsulfosuccinic acid ester salts, alkylphosphoric acid ester salts, and naphthalenesulfonic acid formalin condensates, for example, betaine-type, glycine-type, alanine-type and sulfobetaine-type amphoteric surfactants can be used. These wetting agents and / or surfactants are contained in the range of about 0.5 to 10% by weight, more preferably 1 to 5% by weight, based on the total weight of the desensitizing liquid. The desensitizing solution used in the present invention may further contain fillers such as silicon dioxide, talc and clay in an amount of up to 2% by weight, and dyes and pigments in an amount of up to 1% by weight. it can.

The desensitizing solution used in the present invention is composed of the hydrophilic aqueous solution as described above, but in consideration of the adverse effect on the photosensitive layer of the PS plate, for example, US Pat. No. 4,253,999. No. 4268613 and No. 434
An emulsion type desensitizing liquid as described in each specification such as 8954 can also be used. In order to desensitize the end faces of the PS plate with the desensitizing liquid as described above, the desensitizing liquid can be applied to the end faces of the PS plate one by one, but preferably a large number (for example, (1,000 sheets) PS plates are stacked and applied to the end surface. In this case, for example, JP-B-57-23259 and JP-A-57-9964.
Of course, it is also possible to apply with sandwiching the interleaving paper as described in each publication of No. 7. Also preferred is a method of continuously cutting with the slitter of the present invention and then immediately applying it with a Molton roll containing the desensitizing liquid of the present invention. The dry amount of the desensitizing solution applied to the end surface is 0.0.
01 to 50 g / m ² , preferably 0.01 to 10 g / m ²
m ² and more preferably 0.05 to 5 g / m ² . 0.0
If the amount is less than 01 g / m ² , stains will be generated on the edges. 5
When the amount is more than 0 g / m ² , the plates are stuck to each other and a conveyance failure is likely to occur in the automatic plate making machine.

The photosensitive layer of the photosensitive lithographic printing plate to which the present invention can be applied includes various types, such as a negative type photosensitive composition comprising a diazo resin and a hydrophobic resin, and a positive type comprising an o-quinonediazide compound and a novolac resin. A photopolymerizable composition comprising a photosensitive composition, an addition-polymerizable unsaturated monomer, a photopolymerization initiator, and an organic polymer compound as a binder, or having a —CH═CH—CO— bond in the molecule and photocrosslinking. Examples thereof include those provided with a photosensitive resin that causes a reaction. Typical examples of the negative photosensitive composition include those containing a diazo resin and a binder. Diazo resin is
A diazo resin represented by a condensate of an aromatic azonium salt and an active carbonyl group-containing compound such as formaldehyde. Examples of the diazo resin include organic solvent-soluble diazo resin inorganic salts, which are reaction products of a condensate of p-diazodiphenylamines with aldehydes such as formaldehyde and acetaldehyde, and hexafluorophosphate or tetrafluoroborate, Japanese Patent Publication 47-11
67, sulfonates with the condensate, such as p-toluenesulfonic acid or salts thereof, propylnaphthalenesulfonic acid or salts thereof, butylnaphthalenesulfonic acid or salts thereof, dodecylbenzenesulfonic acid or Examples thereof include an organic solvent-soluble diazo resin organic salt which is a reaction product of the salt, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid or the salt. In particular, a high molecular weight diazo compound containing 20 mol% or more of a hexamer or more described in JP-A-59-78340 is preferable.

Further, 3-methoxy-4-diazo-diphenylamine as disclosed in JP-A-58-27141 is condensed with 4,4'-bis-methoxy-methyl-diphenyl ether to give a mesitylene sulfonate. Those that have been done are also suitable. Further, a copolymer containing, as a structural unit, an aromatic compound having at least one of a carboxyl group, a sulfonic acid group, a sulfinic acid group, a phosphorus oxygen acid group and a hydroxyl group, and a diazonium compound, preferably an aromatic diazonium compound. Condensates are preferred. The binder has an acid content of 0.1 to 3.0 meq / g, preferably 0.2 to 2.0 meq / g, and is substantially water-insoluble (that is, insoluble in neutral or acidic aqueous solution). , An organic polymer compound having a film-forming property, which can be dissolved or swelled in an alkaline aqueous solution and is photocured in the presence of the photosensitive diazo resin to be insolubilized or non-swelled in the developer. It is preferable to convert it into a compound. The acid content
If it is less than 0.1 meq / g, it is difficult to develop it.
If it exceeds, the image strength at the time of development becomes extremely weak.

As a particularly preferable binder, a copolymer containing acrylic acid, methacrylic acid, crotonic acid or maleic acid as an essential component, for example, 2-hydroxyethyl as described in JP-A-50-118802. Acrylate or 2-hydroxyethyl methacrylate, acrylonitrile or methacrylonitrile, multi-component copolymer with acrylic acid or methacrylic acid and optionally other copolymerizable monomers, JP-A-53-12090
Acrylic acid or methacrylic acid, which has a hydroxy group at the terminal and is esterified with a dicarboxylic acid ester residue-containing group, acrylic acid,
Alternatively, a multi-component copolymer with methacrylic acid and optionally other copolymerizable monomers, JP-A-54-98614.
Aromatic hydroxyl group-terminated monomers (for example, N- (4-hydroxyphenyl) methacrylamide), acrylic acid or methacrylic acid, and other copolymerizable compounds as required Examples thereof include multi-component copolymers with various monomers, and multi-component copolymers composed of alkyl acrylate, acrylonitrile or methacrylonitrile and unsaturated carboxylic acid as described in JP-A-56-4144. In addition, acidic polyvinyl alcohol derivatives and acidic cellulose derivatives are also useful. In addition, Japanese Patent Publication No. 54-19773, in which polyvinyl acetal or polyurethane is solubilized with an alkali, JP-A-57.
-94747, 60-182437, 62-5
The binders described in Nos. 8242 and 62-123453 are also useful. Furthermore, the polymer having a maleimide group in the side chain and capable of being photoreticulated as described in JP-B-5-2227 is also useful. The content of the diazo resin and the binder in the photosensitive layer of the photosensitive lithographic printing plate is 3 to 30% by weight of the diazo resin based on the total amount of both, and the binder is 97 to 7%.
0 wt% is suitable. The smaller the content of the diazo resin is, the higher the sensitivity is. However, when the content is lower than 3% by weight, it is insufficient for photo-curing the binder, and the photo-cured film is swollen by the developing solution during development and the film becomes weak. On the other hand, if the content of the diazo resin is more than 30% by weight, the sensitivity becomes low and practically difficult. Therefore, the more preferable range is diazo resin 5
-25% by weight and 95-75% by weight binder.

Examples of the photosensitive compound of the positive type photosensitive composition include o-quinonediazide compounds, of which o-naphthoquinonediazide compounds are representative. o
-As a naphthoquinonediazide compound, Japanese Patent Publication No. 43-
The ester of 1,2-diazonaphthoquinone sulfonic acid chloride and pyrogallol-acetone resin described in 28403 is preferable. Other suitable orthoquinonediazide compounds include those described in US Pat.
There is an ester of 1,2-diazonaphthoquinone-5-sulfonic acid chloride and a phenol-formaldehyde resin described in 3,046,120 and 3,188,210. 1,2-diazonaphthoquinone-4-described in JP-A 96163, JP-A-2-96165 and JP-A-2-96761.
There are esters of sulfonic acid chloride with phenol-formaldehyde resins. Other useful o-naphthoquinonediazide compounds have been reported in numerous patents,
Known ones are listed. For example, JP-A-47
-5303, 48-63802, 48-638
03, 48-96575, 49-38701.
No. 48-13354, Japanese Patent Publication No. 37-18015
No. 41-12122, No. 45-9610, No. 4
9-17481, U.S. Pat. No. 2,977,213,
No. 3,454,400, No. 3,544,323, No. 3,
No. 573,917, No. 3,674,495, No. 3,785,
No. 825, British Patent Nos. 1,227,602 and 1,251,
No. 345, No. 1,267,005, No. 1,329,888
No. 1,330,932, German Patent No. 854,890, and the like.

Polymer compounds having an orthonitrocarbinol ester group described in, for example, Japanese Patent Publication No. 56-2696 are also used in the present invention as a positive-working photosensitive compound without using an o-naphthoquinonediazide compound. can do. Furthermore, a compound that generates an acid by photolysis and a -C-O-C group or-that dissociates by the acid.
Combination systems with compounds having CO-Si groups can also be used in the present invention.

For example, a combination of a compound capable of generating an acid by photolysis with an acetal or O, N-acetal compound (JP-A-48-89003), or a combination of an orthoester or amide acetal compound (JP-A-51-120).
714), a combination with a polymer having an acetal or ketal group in the main chain (JP-A-53-133429),
Combination with enol ether compound (JP-A-55-12)
995), a combination with an N-acylimino carbon compound (JP-A-55-126236), and a polymer having an orthoester group in the main chain (JP-A-56-1).
7345), a combination with a silyl ester compound (JP-A-60-10247) and a combination with a silyl ether compound (JP-A-60-37549, JP-A-60-12).
No. 1446) and the like.

The photosensitive substance used in the photosensitive composition of the present invention includes polyesters, polyamides and polycarbonates containing --CH.dbd.CH--CO-- as a photosensitive group in the polymer main chain or side chain. Those containing such a photosensitive polymer as a main component are also suitable. For example, JP-A-55-40
Photosensitive polyesters obtained by condensation of phenylenediethyl acrylate with hydrogenated bisphenol A and triethylene glycol, as described in U.S. Pat. No. 2,956,878, Examples thereof include (2-propenylidene) malonic acid compounds such as cinnamylidene malonic acid and photosensitive polyesters derived from difunctional glycols.

Further, examples of the photosensitive substance used in the photosensitive composition of the present invention include aromatic azide compounds in which an azide group is bonded to an aromatic ring directly or through a carbonyl group or a sulfonyl group. For example, US Pat.
096,311 and polyazidostyrenes, polyvinyl-p-azidobenzoates, polyvinyl-p-azidobenzals, and azidoarylsulfanyl chlorides and unsaturated hydrocarbons described in JP-B-45-9613. Reaction product with polymer, Japanese Patent Publication No. 43-21
No. 067, No. 44-229, No. 44-22954, and No. 45-24915, such as polymers having a sulfonyl azide or a carbonyl azide. Furthermore, as the photosensitive substance used in the photosensitive composition of the present invention, a photopolymerizable composition comprising an addition polymerizable unsaturated compound can also be used. The present invention can also be applied to a photosensitive composition used for an electrophotographic printing plate. For example, JP-A-55-161250
The photosensitive composition comprising an electron-donating compound, a phthalocyanine-based pigment and a phenol resin, which are used in a printing original plate utilizing electrophotography as described in JP-A No. 1994-242242.

The photosensitive composition is dissolved in the coating solvent of the present invention, and preferably has a dry coating weight of 0.3 to 5.0 g / m ² on an aluminum support having a hydrophilic surface, and is preferably 0.1.
A photosensitive lithographic printing plate can be obtained by coating so as to have a concentration of 5 to 3.5 g / m ² and drying. The solid content concentration of the photosensitive composition at the time of coating is suitably 1.0 to 50% by weight, preferably 2.0 to 30% by weight. As a method for coating the photosensitive composition on the support, conventionally known methods such as roll coating, bar coating, spray coating, curtain coating, and spin coating can be used. The applied photosensitive composition solution is preferably dried at 50 to 150 ° C. As a drying method, the temperature may be initially lowered to be pre-dried and then dried at a high temperature, or may be directly dried at a high temperature.

As the support, aluminum and an aluminum-coated composite support are preferable, and further iron is added to
1-0.5% by weight, 0.03-0.3% by weight of silicon, 0.0% of copper.
A 1S aluminum plate containing 0.001 to 0.03% by weight of titanium and 0.002 to 0.1% by weight of titanium is preferable. The surface of the aluminum material is preferably surface-treated for the purpose of enhancing water retention and improving adhesion with the photosensitive layer. Alkali Preferably, it may be etched by immersing in an aqueous solution of 1 to 30% by weight of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate or the like at a temperature of 20 to 80 ° C. for 5 to 250 seconds. In the etching bath,
You may add aluminum ion about 1/5 of alkali. Then, it is immersed in a 10 to 30 wt% nitric acid or sulfuric acid aqueous solution at a temperature of 20 to 70 ° C. for 5 seconds to 25 seconds to perform neutralization and smut removal after alkali etching. For example, as the roughening method, generally known brush polishing method, ball polishing method, electrolytic etching, chemical etching, liquid honing, methods such as sandblasting, and combinations thereof, and the like, preferably brush polishing method, electrolytic etching, Chemical etching and liquid honing are mentioned, of which the roughening method involving the use of electrolytic etching is particularly preferred. Further, JP-A-54-6390
A method of electrolytically etching after brush-polishing as described in Japanese Patent No. 2 is also preferable.

As the electrolytic bath used in the electrolytic etching, an aqueous solution containing an acid, an alkali or a salt thereof or an aqueous solution containing an organic solvent is used. Of these, hydrochloric acid, nitric acid or their solutions is used. Electrolytes containing salts are preferred. For the brush polishing, it is preferable to use a pumicetone-water suspension and a nylon brush, and it is preferable that the average surface roughness is 0.25 to 0.9 μm. The electrolytic solution used in the electrolytic etching treatment is an aqueous solution of hydrochloric acid or nitric acid, and it is preferable to use it in a concentration range of 0.01 to 3% by weight, and if it is 0.05 to 2.5% by weight, preferable. In addition, in this electrolytic solution, a corrosion inhibitor (or stabilizer) such as nitrate, chloride, monoamines, diamines, aldehydes, phosphoric acid, chromic acid, boric acid, ammonium oxalate, etc. A grain leveling agent, etc. can be added. In addition, an appropriate amount (1-1
(0 g / liter) aluminum ions may be contained.

The electrolytic etching treatment is usually 10 to 60 ° C.
At the temperature of the electrolyte. If the alternating current used at this time has positive and negative polarities exchanged alternately,
Any of a rectangular wave, a trapezoidal wave, and a sine wave can be used, and normal commercial AC single-phase and three-phase AC currents can be used. The current density is 5 to 100 A / dm ² ,
It is desirable to process for 10 to 300 seconds. The surface roughness of the aluminum alloy support of the present invention is adjusted to 0.2 to 0.8 μm by adjusting the amount of electricity.

Further, the surface-roughened aluminum plate is desmutted with an acid or alkali aqueous solution, if necessary. The aluminum alloy grained in this way has 10 to 50% by weight of hot sulfuric acid (40 to 60% by weight).
(° C) or dilute alkali (sodium hydroxide, etc.)
The smut adhering to the surface is preferably removed and etched (preferably in the range of 0.01 to 2.0 g / m ² ). When the smut is removed and etched with an alkali, it is subsequently neutralized by immersing it in an acid (nitric acid or sulfuric acid) for cleaning. After removing the surface smut, an anodic oxide film is provided. As the anodizing method, a conventionally well-known method can be used, but sulfuric acid is used as the most useful electrolytic solution. Next to that, phosphoric acid is also a useful electrolyte. Furthermore, JP-A-55-28400
The mixed acid of sulfuric acid and phosphoric acid disclosed in the publication is also useful.

In the sulfuric acid method, the treatment is usually carried out with a direct current, but it is also possible to use an alternating current. Sulfuric acid concentration 5-3
Electrolytic treatment is carried out for 5 to 250 seconds at a temperature range of 0% by weight and 20 to 60 ° C. to form an oxide film of 1 to 10 g / m ^{2 on} the surface. This electrolytic solution preferably contains aluminum ions. At this time, the current density is 1
-20 A / dm ² is preferable. In the case of the phosphoric acid method,
Phosphoric acid concentration of 50% by weight, at a temperature of 30 to 60 ° C., 10
It is processed at a current density of 1 to 15 A / dm ² for 300 seconds.

Further, if necessary, US Pat. No. 2,71
Silicate (sodium silicate, potassium silicate) treatment described in US Pat. No. 4,066 and US Pat. No. 3,181,461, described in US Pat. No. 2,946,638 Potassium fluorozirconate treatment, phosphomolybdate treatment described in U.S. Pat. No. 3,201,247, alkyl titanate treatment described in British Patent No. 1,108,559, German Patent No. 1,
No. 091,433, polyacrylic acid treatment, German Patent No. 1,134,093 and British Patent No.
1,230,447, polyvinyl phosphonic acid treatment, JP-B-44-6409, phosphonic acid treatment, US Pat. No. 3,307,951 Phytic acid treatment, JP-A-58-1
Treatment with a salt of a hydrophilic organic polymer compound and a divalent metal described in JP-A No. 6893 and JP-A-58-18291, and sulfonic acid described in JP-A-59-101651. A water-soluble polymer having a group and subjected to a hydrophilic treatment by undercoating, JP-A-60-6435.
Those colored with the acid dye described in Japanese Patent No. 2 are particularly preferable. As another hydrophilic treatment method, silicate electrodeposition described in US Pat. No. 3,658,662 can also be mentioned. Further, it is preferable that after the graining treatment and the anodic oxidation, the sealing treatment is performed. Such sealing treatment is performed by immersion in hot water and a hot aqueous solution containing an inorganic salt or an organic salt, a steam bath, or the like.

In addition, the aluminum support may be subbed. Examples of the compound used in the undercoat include phosphonic acids having an amino group such as carboxymethylcellulose, dextrin, gum arabic, and 2-aminoethylphosphonic acid, phenylphosphonic acid which may have a substituent, naphthylphosphonic acid, and alkylphosphone. Acid, organic phosphonic acid such as glycerophosphonic acid, methylenediphosphonic acid and ethylenediphosphonic acid, phenylphosphoric acid which may have a substituent, naphthylphosphoric acid, organic phosphoric acid such as alkylphosphoric acid and glycerophosphoric acid, a substituent May have an organic phosphinic acid such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and a hydroxyl group such as triethanolamine hydrochloride. Water-soluble polymer having hydrochloride Min, a sulfonic acid group as described in JP-A-59-101651, and JP 60-64
Acid dyes and the like described in Japanese Patent No. 352 are preferably used. This undercoat layer can be provided by dissolving the above compound in water, methanol, ethanol, methyl ethyl ketone or the like or a mixed solvent thereof, coating on a support and drying. Further, a yellow dye may be added to improve the tone reproducibility of the photosensitive lithographic printing plate. The coating amount of the undercoat layer after drying is suitably ² to 200 mg / m ² , and preferably 5 to 100 mg / m ² .

On the photosensitive layer, it is preferable to provide a mat layer composed of protrusions provided independently of each other. The purpose of the matte layer is to improve the vacuum adhesion between the negative image film and the photosensitive lithographic printing plate during contact exposure, thereby shortening the vacuuming time and preventing the collapse of fine halftone dots during exposure due to poor adhesion. That is. As the method for applying the matte layer, the method of heat-sealing powdered solid powder described in JP-A-55-12974 and the polymer-containing water described in JP-A-58-182636. There is a method of spraying and drying the above, and any method can be used. It is desirable that the matte layer be composed of a substance that can be dissolved or removed by an aqueous developer containing substantially no organic solvent. A photosensitive lithographic printing plate having a photosensitive composition layer which is applied on a roughened aluminum plate and dried is subjected to imagewise exposure and then developed with an alkaline aqueous solution developer to obtain a relief image. Suitable light sources for exposure include carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, strobes, ultraviolet rays, laser beams and the like.

The alkaline aqueous solution type developing solution used for developing a negative photosensitive lithographic printing plate is described in JP-A-51-774.
No. 01, No. 51-80228, No. 53-44202, and No. 55-52054, the developer having pH = 8 to 13 and water of 75% by weight or more. Those are preferable. If necessary, an organic solvent (benzyl alcohol, ethylene glycol monophenyl ether) whose solubility in water is 10% by weight or less at room temperature, an alkaline agent (triethanolamine, diethanolamine, monoethanolamine, sodium phosphate, sodium carbonate), anionic surfactant Agent (aromatic sulfonate, dialkyl sulfosuccinate, alkyl naphthalene sulfonate, fatty acid salt, alkyl sulfate ester salt),
Nonionic surfactant (polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether,
Polyoxyethylene polyoxypropylene block polymer), antifouling agents (sodium sulfite, sodium salt of sulfopyrazolone) and water softener (ethylenediaminetetraacetic acid tetrasodium salt, nitrotriacetic acid trisodium salt) can be added. However, if organic solvents are contained, toxicity during work, hygiene problems such as odor, fire,
It is more preferable that the organic solvent does not substantially contain the organic solvent, since it causes safety problems such as gas explosion, workability problems such as foaming, pollution problems due to waste liquid, cost problems and the like. As such an aqueous alkaline developer containing substantially no organic solvent, for example, JP-A-59-84241, JP-A-57-192952 and JP-A-62-24263 are used.
It is possible to use a developer composition described in JP-A No. 1993-242242, etc., which is used when developing a positive type lithographic printing plate after imagewise exposure.

The photosensitive lithographic printing plate of the present invention is described in JP-A-54 / 54.
-8002, 55-115045, 59-58
Plate-making processing may be carried out by the method described in each publication of No. 431. That is, after the development treatment, it may be washed with water and then subjected to a desensitizing treatment, or a desensitizing treatment as it is, or a treatment with an acid-containing aqueous solution, or a treatment with an acid-containing aqueous solution, followed by a desensitizing treatment. Furthermore, in the developing step of this type of photosensitive lithographic printing plate, the alkaline aqueous solution is consumed depending on the amount of treatment to reduce the alkaline concentration, or the alkaline concentration is reduced by air due to long-term operation of the automatic developing machine. The ability is lowered, but at that time, JP-A-54-6
As described in 2004, the replenisher may be used to restore the processing capacity. In this case, U.S. Pat. No. 4,882,2
Replenishment by the method described in No. 46 is preferred. Further, the plate making process as described above is disclosed in JP-A-2-705.
It is preferable to carry out with an automatic developing machine as described in JP-A No. 4 and 2-332357. Desensitizing gums that are optionally applied in the final step of the plate making process are Japanese Patent Publications No. 62-16834, No. 62-25118, No. 63-52600, and No. 62-7595.
Those described in JP-A-11693 and JP-A-62-83194 are preferable. After the processing with the developing solution, unnecessary portions of the image area can be erased with a commercially available negative erasing solution or rubbed with a stone stick if necessary.

The developer used for the development of the positive-working photosensitive lithographic printing plate is preferably an alkaline aqueous solution containing substantially no organic solvent, specifically, sodium silicate, potassium silicate, sodium hydroxide, and hydroxide. Potassium, lithium hydroxide, sodium triphosphate, dibasic sodium phosphate, tribasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, aqueous ammonia Aqueous solutions such as are suitable, and their concentration is 0.1
10 to 10% by weight, preferably 0.5 to 5% by weight. Among them, potassium silicate, lithium silicate, a developer containing an alkali silicate such as sodium silicate is preferable because stains are less likely to occur during printing,
The composition of alkali silicate is [SiO ₂ ] / [M] = 0 in molar ratio.
5 to 2.5 (where [SiO ₂ ] and [M] represent the molar concentration of SiO _{2 and} the molar concentration of total alkali metals, respectively) and contain 0.8 to 8% by weight of SiO ₂ . A developing solution is preferably used. Water-soluble sulfites such as sodium sulfite, potassium sulfite, and magnesium sulfite, resorcin, methylresorcin, hydroquinone, and thiosalicylic acid can be added to the developer. The preferred content of these compounds in the developer is 0.002 to 4% by weight, preferably 0.01 to 1% by weight.

Further, in the developing solution, Japanese Patent Laid-Open No. 51324/1975 was used.
Anionic surfactants and amphoteric surfactants as described in JP-A-59-84241 and JP-A-59-75255, JP-A-60-111246 and JP-A-60-213943. Etc. by incorporating at least one of the nonionic surfactants, or as described in JP-A-55-95946 and JP-A-56-142528. By containing, it is possible to enhance the wettability to the photosensitive composition and the stability of development (development latitude), and thus it is preferably used. The amount of such a surfactant added is preferably 0.001 to 2% by weight, and particularly preferably 0.003 to 0.5% by weight. Further, as the alkali metal of the alkali silicate, it is preferable that potassium is contained in an amount of 20 mol% or more based on the total amount of alkali metal since insoluble matters are less generated in the developing solution, and more preferably 9
0 mol% or more, most preferably 100 mol% potassium
Is the case.

Further, the developing solution used in the present invention contains some organic solvents such as alcohol and JP-A-58-190952.
Chelating agent described in Japanese Patent Publication No. 301
A defoaming agent such as a metal salt or an organic silane compound described in JP-A-39 can be added. The photosensitive lithographic printing plate of the present invention is described in JP-A-54-8002 and 55-55.
Needless to say, the plate-making process may be carried out by the methods described in JP-A-115045 and JP-A-59-58431. That is, after the development treatment, it may be washed with water and then subjected to a desensitizing treatment, a desensitizing treatment as it is, a treatment with an aqueous solution containing an acid, or a desensitizing treatment after a treatment with an aqueous solution containing an acid. Furthermore, in the developing step of this type of photosensitive lithographic printing plate, the aqueous alkali solution is consumed depending on the processing amount to reduce the alkali concentration, or the alkali concentration is reduced by air due to long-time operation of the automatic developer. Although the processing capacity is lowered, in this case, JP-A-54-
A replenisher may be used to restore throughput as described in 62004. In this case, U.S. Pat. No. 4,882,24
Replenishment by the method described in No. 6 is preferred.
In addition, the plate-making process as described above is described in JP-A-2-7054.
No. 2-32357, it is preferable to use an automatic processor.

Further, when the photosensitive lithographic printing plate of the present invention is imagewise exposed, developed and water-based or rinsed, and then unnecessary image portions are erased, it is described in JP-B-2-13293. It is preferable to use an erasing liquid as described above. Further, as the desensitizing gum which is optionally applied in the final step of the plate-making process, Japanese Patent Publications No. 62-16834, No. 62-25118, No. 63-52600, and Japanese Patent Laid-Open No. 6-52600 are available.
No. 2-7595, No. 62-11693, No. 62-83.
Those described in each publication of 194 are preferable. Furthermore, when the photosensitive lithographic printing plate of the present invention is imagewise exposed, developed, washed with water or rinsed, erased if desired, and burned after washing with water, JP-B-61-2518 is used before burning. No. 55-28062, JP-A No. 62-31859, and JP-A No. 61-159655.

Synthesis Example 1 4-diazodiphenylamine sulfate (purity 99.5%) 2
9.4 g were slowly added to 70 ml of 96% sulfuric acid at 25 ° C. and stirred for 20 minutes. 3.26 g of paraformaldehyde (purity 92%) was gradually added over about 10 minutes, and the mixture was stirred at 30 ° C. for 4 hours to allow the condensation reaction to proceed. The condensation molar ratio between the diazo compound and formaldehyde is 1: 1. While stirring the reaction product,
It was poured into 2 l of ice water and treated with a cold concentrated aqueous solution in which 130 g of zinc chloride was dissolved. The precipitate was collected by suction filtration, the partially dried solid was dissolved in 1 liter of water, filtered, chilled on ice and washed with potassium hexafluorophosphate.
It was treated with an aqueous solution in which g was dissolved. The precipitate was collected by filtration, and air-dried to give 30.3 g of the polymer-based diazo compound (1).
Got The obtained diazo compound (1) was coupled with 1-phenyl-3-methyl-5-pyrazolone in methyl cellosolve to obtain a dye. The weight average molecular weight of this dye (using a low angle light scattering photometer) was 16,500.
Which corresponded to about 45-mers. The molecular weight distribution of this dye was measured by gel permeation chromatography (GPC).
It was contained at 0 mol%.

[0036]

The present invention will be described below with reference to examples. Example 1 Thickness of JIS A1050 aluminum material containing 0.01% by weight of copper, 0.01% by weight of titanium, 0.3% by weight of iron, and 0.1% by weight of silicon in 99.5% by weight of aluminum. .3
A 0 mm rolled plate was grained on its surface with a 20% by weight aqueous suspension of 400 mesh pumice stone (manufactured by Kyoritsu Kiln Co., Ltd.) and a rotating nylon brush (6,10-nylon), and then washed thoroughly with water. did. This was immersed in a 15% by weight sodium hydroxide aqueous solution (containing 4.5% by weight of aluminum) for etching so that the amount of aluminum dissolved was 5 g / m ² , and then washed with running water. Further, it is neutralized with 1 wt% nitric acid, and then 0.7 wt% nitric acid aqueous solution (aluminum
0.5% by weight), the voltage of the anode is 10.5 V, the voltage of the cathode is 9.3 V, and the alternating waveform voltage (current ratio r = 0.
90, the current waveform described in JP-B-58-5796), and electrolytic surface roughening treatment was performed with an anode-time electric quantity of 160 coulomb / dm ² . After washing with water, 1 at 35 ℃
It was immersed in a 0 wt% sodium hydroxide aqueous solution, etched so that the amount of aluminum dissolved was 1 g / m ² , and then washed with water. Next, it was immersed in a 30% by weight sulfuric acid aqueous solution at 50 ° C., desmutted, and washed with water.

Further, a porous anodic oxide film forming treatment was carried out using a direct current in a 20% by weight aqueous solution of sulfuric acid (containing 0.8% by weight of aluminum) at 35 ° C. That is, electrolysis was performed at a current density of 13 A / dm ² , and the anodic oxide film weight was set to 2.7 g / m ² by adjusting the electrolysis time. In order to prepare a negative photosensitive lithographic printing plate using a diazo resin and a binder, this support was washed with water, immersed in a 3% by weight aqueous solution of sodium silicate at 70 ° C. for 30 seconds, washed with water and dried.
The aluminum support obtained as described above has a reflection density of 0.30 as measured with a Macbeth RD920 reflection densitometer.
The center line average roughness was 0.58 μm. Next, methyl methacrylate / ethyl acrylate / 2 was added to the above support.
-Acrylamido-2-methylpropanesulfonic acid sodium copolymer (average molecular weight of about 60,000) (molar ratio 50/3
0/20) of 1.0 wt% aqueous solution was applied by a roll coater so that the applied amount after drying was 0.05 g / m ² . Further, the following photosensitive solution-1 was applied using a bar coater and dried at 110 ° C. for 45 seconds. The dry coating amount is 2.
It was 0 g / m ² .

[0038] Photosensitive liquid-1   0.50 g of diazo resin of Synthesis Example 1   Binder-1 5.00 g   Stilite HS-2 (manufactured by Daido Industry Co., Ltd.) 0.10 g   Victoria Pureable-BOH 0.15g   Tricresyl phosphate 0.50g   Dipicolinic acid 0.20g   FC-430 (3M surfactant) 0.05 g solvent   1-methoxy-2-propanol 25.00g   Methyl lactate 12.00g   Methanol 30.00g   Methyl ethyl ketone 30.00 g   3.00g of water

Binder-1 is 2-hydroxyethyl methacrylate / acrylonitrile / methyl methacrylate / methacrylic acid copolymer (weight ratio 50/20/26 /
4, a water-insoluble, alkaline water-soluble film-forming polymer having an average molecular weight of 75,000 and an acid content of 0.4 meq / g).
Stilite HS-2 (manufactured by Daido Industry Co., Ltd.) is a polymer compound having higher oil sensitivity than the binder, and styrene / maleic acid mono-4-methyl-2-pentyl ester = 5.
It was a 0/50 (molar ratio) copolymer and had an average molecular weight of about 100,000.

The thickness thus obtained is 0.3 mm and the width is 800 mm.
A coil-shaped photosensitive lithographic printing plate having a width of 398 mm and a lower cutting blade (X = 100 μm, Y = 500 μm) shown in FIG. Slits were continuously formed so that (X = 100 μm, Y = 500 μm). Then, an aqueous solution of 5 g of sodium hexametaphosphate and 95 g of pure water was continuously applied as a desensitizing solution to the side surface of the curved aluminum support with a Molton roll so that the dry weight was 0.1 g / m ^2, and It was continuously cut to a size of 560 mm, and 1000 sheets were stacked and packaged. After one week, the cut sheet-shaped photosensitive lithographic printing plate was imagewise exposed and DN-3C (Fuji Photo Film Co., Ltd. alkaline aqueous solution developer) was exposed with 800H (Fuji Photo Film Co., Ltd. automatic developing machine). Was developed with a solution diluted 1: 1 with water, and immediately, a solution prepared by diluting FN-2 (a gum solution manufactured by Fuji Photo Film Co., Ltd.) 1: 1 with water was applied and dried. The next day, this printing plate was placed on an offset rotary printing machine using a newspaper ink from Sakata Ink Co., Ltd. and Toyo Ink Co., Ltd. Toyo Alky fountain solution to produce 100,000.
20,000 sheets were printed at a speed of 1 sheet / hour. No stain was found on the printing paper surface corresponding to the edge of the printing plate.

Example 2 In the same manner as in Example 1, a coil-shaped photosensitive lithographic printing plate was prepared. This photosensitive lithographic printing plate was cut with a lower cutting blade (X =
100 μm, Y = 500 μm), the end portion as shown in FIG. 5 is curved to the lower surface side, and a flat portion is formed at the lower surface side end portion of the curved portion (X = 100 μm, Y
= 500 μm, Z = 50 μm). Then, in the same manner as in Example 1, a desensitizing solution was applied to the side surface of the aluminum support, and as in Example 1,
Plate made and printed. No dirt was found on the end faces.

Examples 3 to 25 In the same manner as in Example 1, a coil-shaped photosensitive lithographic printing plate was prepared. Various lower cutting blades of the photosensitive lithographic printing plate were changed to prepare photosensitive lithographic printing plates in which the widths of X, Y and Z were changed as shown in FIGS. Table 1 shows the numbers of the examples. Then, the desensitizing solution was applied to the side surface of the aluminum support in the same manner as in Example 1, and the plate was made and printed in the same manner as in Example 1. No dirt was generated on the end face at any level. In particular, Examples 15, 16, 17, 18, 2
Nos. 0, 21, 22, 23, 24, and 25 did not stain on the end faces even under the printing conditions in which the amount of dampening water was reduced and the amount of ink was increased.

[0043]

[Table 1] Z (μm) 0 10 100 1000 Y (μm) 40 100 500 2000 40 100 500 2000 500 2000 2000 X (μm) 20 3 4 6 − 11 12 14 − 19 − − 50 − 5 7 9 − 13 15 17 20 22 24 200 − − 8 10 − − 16 18 21 23 25

Examples 26 to 35 In the same manner as in Example 2, a coil-shaped photosensitive lithographic printing plate was prepared and continuously slit so as to have the same end shape as in Example 2. Thereafter, the desensitizing solution shown in Table 2 was applied to the side surface of the aluminum support, and plate making was carried out in the same manner as in Example 1,
Printed. In any case, the end face was not soiled.

[0045]

[Table 2] Example Side coating liquid Dry coating amount 26 Sodium hexametaphosphate 1 (g) 0.02 (g / m ² ) Pure water 99 27 Sodium hexametaphosphate 20 (g) 0.40 (g / m ² ) Pure water 80 28 Hexametalline Sodium acid salt 5 (g) 0.10 (g / m ² ) Pure water 94 Phosphoric acid (85% by weight aqueous solution) 1 29 Sodium hexametaphosphate 5 (g) 0.30 (g / m ² ) Pure water 85 Phosphoric acid ( 85 wt% aqueous solution) 10 30 Phytic acid (30 wt% aqueous solution) 3 (g) 0.02 (g / m ² ) Pure water 97 31 Phytic acid (30 wt% aqueous solution) 15 (g) 0.10 (g / m ² ) Pure water 85 32 Arabia gum (30 wt% aqueous solution) 3 (g) 0.02 (g / m ² ) Pure water 97 33 Arabia gum (30 wt% aqueous solution) 15 (g) 0.10 (g / m ²⁾ ) Pure water 85 34 sodium hexametaphosphate Um 5 (g) 0.15 (g / m 2) Pure water 91 phosphoric acid (85 wt% aqueous solution) 1 gum arabic (30 wt% aqueous solution) 3 35 phytic acid (30 wt% aqueous solution) 15 (g) 0.12 (G / m ² ) Pure water 82 Arabia gum (30 wt% aqueous solution) 3

Comparative Examples 1 and 2 In the same manner as in Example 1, a photosensitive lithographic printing plate in the form of a coil was coated with a photosensitive layer, dried, and slit into 398 mm to form a photosensitive lithographic printing plate.
Slitting was continuously performed in the same manner as in Nos. 2 and 3. The sample to which the desensitizing liquid of Example 1 was not applied was designated as Comparative Example 1, and the sample to which the desensitizing liquid of Example 2 was not applied was designated as Comparative Example 2. Then, in the same manner as in Example 1, the plate was made and printed. In both Comparative Examples 1 and 2, thin linear stains were generated on the printing paper surface corresponding to the edges of the printing plate. In particular, dark linear stains were generated under the condition of reducing the dampening water amount, the condition of increasing the ink amount, and the condition of decreasing the dampening water amount and increasing the ink amount.

Comparative Examples 3 to 6 A coil-shaped photosensitive lithographic printing plate was prepared in the same manner as in Example 1 and was continuously prepared using a conventional lower cutting blade having no step different from that shown in FIGS. 2 and 4. I slit. Then, the desensitizing solution shown in Table 3 was applied to the side surface of the aluminum support, and the plate was made and printed in the same manner as in Example 1. In each case, a thin linear stain was generated on the printing paper surface corresponding to the edge of the printing plate.
In particular, dark linear stains were generated under the condition of reducing the dampening water amount, the condition of increasing the ink amount, and the condition of decreasing the dampening water amount and increasing the ink amount.

[0048]

[Table 3] Comparative Example Side coating liquid Dry coating amount 3 Sodium hexametaphosphate 5 (g) 0.10 (g / m ² ) Pure water 95 4 Sodium hexametaphosphate 5 (g) 0.30 (g / m ² ) Pure water 85 Phosphoric acid (85% by weight aqueous solution) 10 5 phytic acid (30% by weight aqueous solution) 15 (g) 0.10 (g / m ² ) pure water 85 6 arabia gum (30% by weight aqueous solution) 15 (g) 0.10 (g / m ² ) Pure water 85

Comparative Example 7 A coil-shaped photosensitive lithographic printing plate was prepared in the same manner as in Example 1 and was continuously slit using the same conventional lower cutting blade as in Comparative Examples 3 to 6. After that, the desensitizing solution was not applied to the side surface of the aluminum support, and the plate was made and printed in the same manner as in Example 1. Dark linear stains were generated on the printing paper surface corresponding to the edges of the printing plate.

[0050]

As is clear from the above examples, in the printing plate produced from the photosensitive lithographic printing plate of the present invention, the printing paper surface corresponding to the edge portion does not stain.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a cutting portion of a slitter device.

FIG. 2 shows a first embodiment of the shape of the tip of the lower cutting blade of the present invention.

FIG. 3 shows an end portion 30a of an aluminum sheet 30.

FIG. 4 shows a second embodiment of the shape of the tip of the lower cutting blade.

FIG. 5 shows an end portion 35a of an aluminum sheet 35.

[Explanation of symbols]

10a, 10b ... upper cutting blade 11 ... Rotation axis 20a, 20b ... Lower cutting blade 21 ... Rotation axis 25 ... Lower cutting blade 30 …… Aluminum sheet 30a ... end 35: Aluminum sheet 35a ... curved section 35b ... flat part

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41N 1/08 B41N 3/00 B41N 3/03 501

Claims (3)

(57) [Claims] 1. A photosensitive lithographic printing plate in which a photosensitive layer is provided on an aluminum support having a hydrophilic surface, and has a chamfered or stepped lower cutting blade.
By cutting with a liter device, the end portion of the aluminum support body is curved to the lower surface side, and X is 10 to 10 in the aluminum plate shape of FIG.
200 μm, Y is 20 to 3000 μm, and the side surface of the curved photosensitive layer surface is subjected to a desensitizing treatment. 2. The end portion protruding toward the lower surface of the curved side,
A flat portion parallel to the lower surface is provided.
The photosensitive lithographic printing plate described. 3. The photosensitive lithographic plate according to claim 1, wherein the desensitizing treatment liquid contains at least one of a hydrophilic organic polymer compound, hexametaphosphoric acid and its salt, phytic acid and its salt. Printed version.