JPH1152579A - Photosensitive planographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a planographic printing plate not causing contamination at ends by imparting convexly curved faces made hydrophilic all over to the tops of ends of opposite two sides of an aluminum substrate and desensitizing the curved faces. SOLUTION: An aluminum sheet 30 is degreased, washed, grained, anodized, made hydrophilic, coated with a photosensitive liq. and dried. Ends of opposite two sides of the sheet 30 are then slit to a size fit for a desired printing machine. At this point, the ends are formed so as to impart convexly curved faces and they are cut so that the curved faces become hydrophilic all over. The curved faces are then desensitized with a sensitizing soln., preferably an aq. soln. contg. at least one compd. selected from among a hydrophilic org. high molecular compd., hexametaphosphoric acid, its salt, pheytic acid and its salt.

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, and more particularly, to a photosensitive lithographic printing plate capable of obtaining a lithographic printing plate having no stain on its edges.

[0002]

2. Description of the Related Art A photosensitive lithographic printing plate using an aluminum plate as a support is commercially available and widely used. As a method for producing such a photosensitive lithographic printing plate, generally, various surface treatments such as graining, anodic oxidation, and chemical conversion treatment are applied to a sheet-like or coil-like aluminum plate alone or in an appropriate combination, and then a photosensitive liquid is applied. , Dried and then cut to a desired size. When printing such a photosensitive lithographic printing plate using a printing plate obtained by processing such as image exposure and development, when printing on paper smaller than the size of the printing plate using a normal sheet-fed printing machine There is no problem when the part corresponding to the edge of the printing plate does not become the printing surface as in the above, but when printing continuously on roll paper using a rotary press such as newspaper printing, printing is not necessary. Since the end portion of the plate becomes the printing surface, the ink adhering to the end portion is also printed on paper and becomes stained, thereby significantly impairing the commercial value of the printed matter. As a method of preventing the end portion of the printing plate from being stained, for example, Japanese Patent Publication No. 57-46754 discloses a method in which an angle θ between an end portion of an aluminum support and an aluminum surface is 10 to 45 °. A method for cutting is disclosed, but when 10,000 or more sheets are printed, ink is accumulated at the edges and stains occur. Japanese Patent Application Laid-Open No. 9-52466 discloses a lithographic printing plate characterized in that a corner formed between a surface having a hydrophilic layer of an aluminum support and an end surface is formed of a convex curved surface. However, the entire corners were not subjected to a hydrophilic treatment, and the prevention of contamination was insufficient. Further, if the end of the corner portion is to be hydrophilized, the surface of the hydrophilic layer is cracked when cut into such a shape, and the ink is fixed to the cracked portion, thereby causing stain. In addition, Japanese Patent Publication 62-61
No. 946 discloses a method of desensitizing the end face of an aluminum support, and JP-A-63-256495 discloses a method of preliminarily hydrophilizing the end face of a printing plate of an aluminum support. Although disclosed, it is still inadequate and further improvements were desired.

[0003]

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

[0004]

The 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, wherein at least two opposite sides of the aluminum support are provided. Can be achieved by a photosensitive lithographic printing plate characterized in that the upper surface of the end is a curved surface that is hydrophilic and is convex over the entire surface and the curved surface is subjected to a desensitization treatment.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in more detail.
First, a sheet-like or coil-like aluminum plate is degreased and washed by various methods, grained by various methods, then, if necessary, the residue is removed, anodized, hydrophilized, and coated with a photosensitive solution. And dry. Then, when slitting the two opposite ends to a size suitable for the desired printing press, the upper surface of the end is bent to the lower surface side, that is, the curved surface formed in the upward convex shape, An end is formed so that it becomes. At this time, the end is cut so that the entire curved surface is hydrophilized. The shape of the notch in the cross section of the end portion of the support is such that the cutting sag height is preferably 30 to 100 μm, more preferably 40 to 80 μm, and the area of the notch is preferably 500 to 20000 μm ² , more preferably 20 to 20 μm ² .
It is 00 to 15000 μm ² . Further, it is preferable to set conditions for slitting such that the entire curved surface has a hydrophilic surface. Further, a photosensitive layer is present on the curved hydrophilic surface.

FIG. 1 is a sectional view showing a cutting portion of the 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 circular blade on a disk, and upper cutting blades 10a and 1
0b is supported on the rotating shaft 11, and the lower cutting blades 20a and 20b are supported on the rotating shaft 21 coaxially. The upper cutting blades 10a and 10b and the lower cutting blade 20a
And 20b are rotated in opposite directions. The aluminum sheet 30 is cut between the upper cutting blades 10a and 10b and the lower cutting blades 20a and 20b to a predetermined width. More specifically, the gap between the upper cutting blade 10a and the lower cutting blade 20a and the gap between the upper cutting blade 10b and the lower cutting blade 20b of the cutting unit of the slitter device of FIG. 1 are preferably reduced to 30 to 100 μm. This is set to form an end having a shape as shown in FIG. FIG. 2 shows the shapes of the upper cutting blade 10a and the lower cutting blade 20a of the present invention. FIG. 3 is an enlarged view of the portion A in FIG. 2 and shows the tip shape of the upper cutting blade 10a, the tip shape of the lower cutting blade 20a, and the gap between the upper cutting blade and the lower cutting blade. FIG. 4 shows the cross-sectional shape of the aluminum sheet of Example 1 in which the gap between the upper cutting blade and the lower cutting blade was cut by 50 μm using the slitter device of FIG. 1 and the cutting blade of FIG.

The shape of the notch in FIG. 4 is preferably convexly curved, and more preferably a convex curved shape having no bent portion. In the case where a bent portion is provided, ink may adhere to the bent portion and stain may occur. The preferred range of the sagging height (X) in FIG. 4 is 30 to 100 μm, and the more preferred range is 40 to 80 μm. The preferred range of the area of the notch in FIG. 4 (Y) is 500~20000μm ^2, a more preferred range is 2000~15000μm ^2. FIG.
If the sagging height (X) is less than 30 μm, dirt is generated at the end. Further, when the sagging height (X) is larger than 100 μm, the burr height (projection to the lower surface) in FIG. 4 becomes large, causing a problem of generation of cutting chips. If the area of the notch (Y) in FIG. 4 is smaller than 500 μm ² , dirt is generated at the end. Also, the area (Y) of the notch in FIG.
4 is greater than 20000 μm ² , the burr height in FIG. 4 is increased, cutting chips are generated, and the printing durability of the image portion near the edge is reduced.

[0008] After cutting the opposite two or four sides of the photosensitive lithographic printing plate so as to form a curved surface whose entire convex surface is hydrophilic, the curved surface is further desensitized. Surprisingly, by performing the treatment, the stain on the end portion was greatly improved despite the desensitization treatment performed from above the photosensitive layer on the curved surface. As the desensitizing liquid used in the desensitizing treatment, a desensitizing liquid used in the desensitizing treatment of a lithographic printing plate using an aluminum plate as a support can be effectively used. Preferred examples of the desensitizing liquid include an aqueous solution containing at least one of a hydrophilic organic polymer compound, hexametaphosphoric acid and a salt thereof, and phytic acid and a salt thereof.

Specific examples of the hydrophilic organic high molecular compound include gum arabic, dextrin, alginate such as sodium alginate, water-soluble cellulose such as carboxymethylcellulose, hydroxyethylcellulose and hydroxypropylmethylcellulose;
Polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, water-soluble copolymer containing acrylamide units, polyacrylic acid, copolymer containing acrylic acid units,
Polyacrylic acid, copolymer containing acrylic acid units, polymethacrylic acid, copolymer containing methacrylic acid units, copolymer of vinyl methyl ether and maleic anhydride, copolymer of vinyl acetate and maleic anhydride And a phosphoric acid-modified starch. Among them, gum arabic is preferable since it has a strong desensitizing effect. These hydrophilic polymer compounds can be used in combination of two or more as necessary, and are used at a concentration of about 1 to 40% by weight, more preferably 3 to 30% by weight.

Specific examples of hexametaphosphate include alkali metal hexametaphosphate and ammonium hexametaphosphate. Examples of the alkali metal or ammonium hexametaphosphate include sodium hexametaphosphate, potassium hexametaphosphate, and ammonium hexametaphosphate. Specific examples of phytic acid or salts thereof include alkali metal salts such as sodium salt, potassium salt, and lithium salt, ammonium salts, and amine salts. As amine salts, 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, Salts such as allylamine and aniline can be mentioned. The phytate may be a normal salt in which all 12 hydrogens of an acid are substituted, a hydrogen salt in which a part of the acid hydrogen is substituted (an acidic salt), or a simple salt composed 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.

The desensitizing solution used in the present invention preferably further contains a metal salt of a strong acid, whereby the desensitizing effect can be enhanced. Specific metal salts of strong acids include sodium and potassium nitrates,
Magnesium, calcium and zinc salts, sodium, potassium, magnesium, calcium and zinc salts of sulfuric acid, sodium, potassium, magnesium, calcium, and zinc salts of chromic acid, and sodium and fluoride salts Potassium iodide and the like can be mentioned.
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 preferred. 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. Thus, if the pH of the aqueous phase is not acidic, more acid is added to the aqueous phase. Examples of the acid added as such a pH adjuster include mineral acids such as phosphoric acid, sulfuric acid, and nitric acid, for example, citric acid, tarnic acid, malic acid, glacial acetic acid, lactic acid, oxalic acid, p-toluenesulfonic acid, and organic phosphonic acid. And the like. Of these, phosphoric acid is particularly excellent because it not only functions as a pH adjuster, but also has the effect of enhancing the desensitizing effect, and is 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.

It is preferable that the desensitizing solution used in the present invention contains a wetting agent and / or a surfactant, whereby the applicability of the desensitizing solution can be improved. As specific wetting agents, lower polyhydric alcohols are preferable, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, pentanediol, hexylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, and tripropylene Examples include glycol, glycerin, sorbitol, pentaerythritol and the like, and particularly preferred is glycerin. Examples of the surfactant include nonionic surfactants such as polyoxyethylene alkyl phenyl ether and polyoxyethylene polyoxypropylene block copolymers, such as fatty acid salts, alkyl sulfates, alkyl benzene sulfonates, and alkyl naphthalene sulfonates. Anionic surfactants such as dialkylsulfosuccinate salts, alkylphosphate 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 solution. 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 comprises a hydrophilic aqueous solution as described above. In consideration of a case where the photosensitive layer of the PS plate is adversely affected, for example, US Pat. No. 4,253,999. No. 4,268,613, No. 434
Emulsifying desensitizing liquids such as those described in the respective specifications such as No. 8954 can also be used. In order to desensitize the curved surface of the PS plate end with the desensitizing liquid as described above,
The desensitizing liquid can be applied one by one to the curved surface of the PS plate, but preferably a large number (for example, 1000)
Is applied to the curved surface in a state of being stacked by a sponge, a Molton roll, an air spray or the like. In this case, for example, Japanese Patent Publication No. 57-23259,
Of course, it is also possible to apply in a state where an interleaf is sandwiched as described in each publication of -99647. Further, a method of applying the liquid while supplying it to the upper blade of the slitter apparatus of the present invention while cutting, and after continuously cutting with a slitter, immediately apply by a Molton roll or the like containing the desensitizing liquid of the present invention. The method is also preferred. Also, at this time, it is preferable that the end face be simultaneously desensitized. The amount of the desensitizing liquid applied to the curved surface is 0.001 to 50 g / m ² , preferably 0.01 to 10 g / m ² , more preferably 0.05 in terms of dry weight.
５5 g / m ² . If less than 0.001 g / m ² ,
Stain occurs at the end. If more than 50 g / m ² ,
Plates are stuck together and transport failures easily occur in automatic plate making machines.

The photosensitive layer of the photosensitive lithographic printing plate to which the present invention can be applied includes various photosensitive layers, such as a negative photosensitive composition comprising a diazo resin and a hydrophobic resin, and a positive photosensitive composition comprising an o-quinonediazide compound and a novolak resin. -Type photosensitive composition, an addition-polymerizable unsaturated monomer, a photopolymerization initiator and a photopolymerizable composition comprising 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. A typical negative photosensitive composition includes a composition containing a diazo resin and a binder. The diazo resin is a diazo resin represented by a condensate of an aromatic diazonium salt and a compound containing an active carbonyl group, for example, formaldehyde. As the diazo resin, for example,
an organic solvent-soluble inorganic salt of a diazo resin which is a reaction product of a condensate of p-diazodiphenylamines with an aldehyde such as formaldehyde or acetaldehyde and hexafluorophosphate or tetrafluoroborate;
Sulfonates with the condensate as described in JP-A-7-1167, for example, p-toluenesulfonic acid or a salt thereof, propylnaphthalenesulfonic acid or a salt thereof, butylnaphthalenesulfonic acid or a salt thereof, dodecylbenzenesulfone Acid or a salt thereof, 2-hydroxy-
An organic solvent-soluble diazo resin organic salt which is a reaction product with 4-methoxybenzophenone-5-sulfonic acid or a salt thereof is exemplified. In particular, a high molecular weight diazo compound containing at least 20 mol% of a hexamer or more described in JP-A-59-78340 is preferable.

Also, 3-methoxy-4-diazo-diphenylamine as disclosed in JP-A-58-27141 is condensed with 4,4'-bis-methoxy-methyl-diphenyl ether to form a mesitylene sulfonate. What is done is also suitable. Further, a copolymer containing at least one of a carboxyl group, a sulfonic acid group, a sulfinic acid group, an oxygen acid group of phosphorus, and a hydroxyl group, and a diazonium compound, preferably an aromatic diazonium compound, as structural units. Condensates are preferred. Preferred binders have an acid content of 0.1 to 3.0 m.
eq / g, preferably 0.2 to 2.0 meq / g, which is a substantially water-insoluble (ie, insoluble in a neutral or acidic aqueous solution) and film-forming organic polymer compound, Those which can be dissolved or swelled in an aqueous alkali-based developer and are photo-cured in the presence of the photosensitive diazo resin to make them insoluble or non-swellable in the developer are preferred. When the acid content is less than 0.1 meq / g, development is difficult, and when the acid content exceeds 3.0 meq / g, the image intensity during development is significantly reduced.

Particularly preferred binders are copolymers containing acrylic acid, methacrylic acid, crotonic acid or maleic acid as essential components, for example, 2-hydroxyethyl as described in JP-A-50-118802. Multi-component copolymers of acrylate or 2-hydroxyethyl methacrylate, acrylonitrile or methacrylonitrile, acrylic acid or methacrylic acid and, if necessary, other copolymerizable monomers, JP-A-53-12090
Acrylic or methacrylic acid, acrylic acid, in which the terminal is a hydroxy group and esterified with a group containing a dicarboxylic acid ester residue as described in JP-A-3
Or a multi-component copolymer of methacrylic acid and, if necessary, another copolymerizable monomer, JP-A-54-98614.
No. 4,086,098, and a monomer having an aromatic hydroxyl group at the terminal thereof (for example, N- (4-hydroxyphenyl) methacrylamide, etc.), acrylic acid or methacrylic acid, and other copolymerizable if necessary. And a multi-component copolymer comprising an alkyl acrylate, acrylonitrile or methacrylonitrile and an unsaturated carboxylic acid as described in JP-A-56-4144. In addition, acidic polyvinyl alcohol derivatives and acidic cellulose derivatives are also useful. Japanese Patent Publication No. 54-19773, in which polyvinyl acetal or polyurethane is alkali-soluble,
Nos. -94747, 60-182437 and 62-5
The binders described in Nos. 8242 and 62-123453 are also useful. Further, a polymer having a maleimide group in the side chain and capable of photoreticulation 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 and the binder is 97 to 7 based on the total amount of both.
0% by weight is suitable. When the content of the diazo resin is small, the sensitivity is high, but when the content is lower than 3% by weight, it is insufficient for photocuring the binder, and the photocured film swells with the developing solution during development, and the film becomes weak. Conversely, if the content of the diazo resin is more than 30% by weight, the sensitivity is lowered and practical difficulties arise. Therefore, a more preferable range is the diazo resin 5
-25% by weight and 95-75% by weight of binder.

The photosensitive compound of the positive photosensitive composition includes an o-quinonediazide compound, and a representative example thereof is an o-naphthoquinonediazide compound. o
-As a naphthoquinonediazide compound, JP-B-43-
Preferred is an ester of 1,2-diazonaphthoquinonesulfonic acid chloride and pyrogallol-acetone resin described in JP-A-28403. Other suitable orthoquinonediazide compounds include U.S. Pat.
There are esters of 1,2-diazonaphthoquinone-5-sulfonic acid chloride and phenol-formaldehyde resin described in 3,046,120 and 3,188,210. 96163, JP-A-2-96165, and JP-A-2-96661, 1,2-diazonaphthoquinone-4-
There are esters of sulfonic chloride and phenol-formaldehyde resin. Other useful o-naphthoquinonediazide compounds have been reported in numerous patents,
There are known ones. For example,
No.-5303, No.48-63802, No.48-638
No. 03, No. 48-96575, No. 49-38701
No. 48-13354, JP-B-37-18015
No. 41-11222, No. 45-9610, No. 4
No. 9-17481, U.S. Pat. No. 2,797,213,
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.

As a photosensitive compound which acts positively without using an o-naphthoquinonediazide compound, for example, a polymer compound having an orthonitrocarbinol ester group described in JP-B-56-2696 is also used in the present invention. can do. Further, a compound generating an acid by photolysis and a -COC group or-dissociated by the acid.
Combinations with compounds having a CO-Si group 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 an O, N-acetal compound (JP-A-48-90303), a combination with 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
No. 995), a combination with an N-acylimino carbon compound (JP-A-55-126236), a combination with a polymer having an orthoester group in the main chain (JP-A-56-1).
No. 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).

The photosensitive substance used in the photosensitive composition of the present invention includes polyesters, polyamides and polycarbonates containing -CH = CH-CO- as a photosensitive group in the polymer main chain or side chain. A polymer containing such a photosensitive polymer as a main component is 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 US Pat. No. 2,956,878, as described in US Pat. Examples thereof include (2-propenylidene) malonic acid compounds such as cinnamylidenemalonic acid and photosensitive polyesters derived from bifunctional glycols.

Further, examples of the photosensitive substance used in the photosensitive composition of the present invention include an aromatic azide compound in which an azide group is bonded to an aromatic ring directly or via a carbonyl group or a sulfonyl group. For example, U.S. Pat.
Polyazide styrene, polyvinyl-p-azidobenzoate, polyvinyl-p-azidobenzal described in JP-A-096,311; and azidoarylsulfanyl chlorides described in JP-B-45-9613 and unsaturated hydrocarbons. Reaction product with polymer, and JP-B-43-21
And polymers having a sulfonyl azide or a carbonyl azide, as described in JP-A Nos. 067, 44-229, 44-22954, and 45-24915. 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
And a photosensitive composition comprising an electron-donating compound, a phthalocyanine-based pigment, and a phenol resin used for a printing plate using electrophotography described in (1).

The photosensitive composition is dissolved in the above-mentioned coating solvent, and is preferably applied to an aluminum support having a hydrophilic surface in a dry coating weight of 0.3 to 5.0 g / m ² , preferably 0.5 to 5.0 g / m ^2. 3.
It is applied to a concentration of 5 g / m ² and dried to obtain a photosensitive lithographic printing plate. The solid content concentration of the photosensitive composition at the time of coating is suitably 1.0 to 50% by weight, preferably
2.0-30% by weight is suitable. As a method for applying the photosensitive composition on the support, a conventionally known method, for example, a method such as roll coating, bar coating, spray coating, curtain coating, and spin coating can be used. The applied photosensitive composition solution is 50
Drying at ~ 150 ° C is preferred. As a drying method, after preliminarily drying at a lower temperature, drying may be performed at a high temperature or directly at a high temperature.

As the support, aluminum and an aluminum-coated composite support are preferable.
1 to 0.5% by weight, 0.03 to 0.3% by weight of silicon, and 0.3% by weight of copper.
A 1S aluminum plate containing 001 to 0.03% by weight and further 0.002 to 0.1% by weight of titanium is preferable. The surface of the aluminum material is desirably surface-treated for the purpose of increasing water retention and improving adhesion to the photosensitive layer. Alkali, preferably, may be etched by immersing it 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,
Aluminum ions may be added to about one fifth of the alkali. Then, it is immersed in an aqueous solution of 10 to 30% by weight of nitric acid or sulfuric acid at a temperature of 20 to 70 ° C. for 5 to 25 seconds to neutralize and remove smut after alkali etching. For example, as the surface roughening method, generally known brush polishing method, ball polishing method, electrolytic etching, chemical etching, liquid honing, sand blasting and the like and combinations thereof, and preferably, brush polishing method, electrolytic etching, Chemical etching and liquid honing are mentioned, of which the surface roughening method including the use of electrolytic etching is preferred. Further, JP-A-54-6390
As described in Japanese Patent Publication No. 2 (1994), a method of performing electrolytic polishing after brush polishing 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. Electrolytes containing salts are preferred. For brush polishing, it is preferable to use a pamistone-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 for the electrolytic etching treatment is an aqueous solution of hydrochloric acid or nitric acid, and the concentration is preferably used in the range of 0.01 to 3% by weight, and more preferably 0.05 to 2.5% by weight. preferable. In addition, a corrosion inhibitor (or stabilizer) such as nitrate, chloride, monoamines, diamines, aldehydes, phosphoric acid, chromic acid, boric acid, ammonium oxalate, etc., if necessary, A graining agent and the like can be added. Also, an appropriate amount (1 to 1)
0 g / liter) of aluminum ions.

The electrolytic etching process is usually performed at 10 to 60 ° C.
At the temperature of the electrolyte. If the alternating current used at this time is one in which the positive and negative polarities are alternately exchanged,
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 in the present invention is adjusted by the quantity of electricity, and is set to 0.2 to 0.8 μm.

Further, the roughened aluminum plate is desmutted with an aqueous solution of an acid or an alkali, if necessary. The grained aluminum alloy is made of 10 to 50% by weight of hot sulfuric acid (40 to 60% by weight).
℃) or dilute alkali (such as sodium hydroxide)
The smut attached to the surface is preferably removed and etched (preferably in the range of 0.01 to 2.0 g / m ² ). If the smut has been removed and etched with an alkali, it is subsequently neutralized by immersion in an acid (nitric acid or sulfuric acid) for cleaning. After de-smutting the surface, an anodic oxide coating is provided. As the anodic oxidation method, a conventionally well-known method can be used, but sulfuric acid is used as the most useful electrolytic solution. Subsequently, phosphoric acid is also a useful electrolyte. Further, 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 performed with a direct current, but an alternating current can be used. Sulfuric acid concentration 5-3
Electrolysis treatment is performed at 0% by weight in a temperature range of 20 to 60 ° C. for 5 to 250 seconds, and an oxide film of 1 to 10 g / m ² is provided on the surface. The electrolyte preferably contains aluminum ions. At this time, the current density is 1
~20A / dm ² is preferred. In the case of the phosphoric acid method, 5-
At a phosphoric acid concentration of 50% by weight and a temperature of 30 to 60 ° C., 10
300 seconds, is treated at a current density of 1 through 15A / dm ^2.

Further, if necessary, US Pat.
The silicate (sodium silicate, potassium silicate) treatment described in US Pat. No. 4,066 and US Pat. No. 3,181,461 and the process described in US Pat. No. 2,946,638 are described. Potassium fluoride zirconate treatment, phosphomolybdate treatment described in U.S. Pat. No. 3,201,247, alkyl titanate treatment described in British Patent 1,108,559, German Patent No. 1,
No. 091,433, polyacrylic acid treatment, German Patent 1,134,093 and British Patent No.
1,230,447, polyvinylphosphonic acid treatment described in JP-B-44-6409, and U.S. Pat. No. 3,307,951. Phytic acid treatment, JP-A-58-1
No. 6,893 and JP-A-58-18291, the treatment with a salt of a hydrophilic organic polymer compound with a divalent metal, and the sulfonic acid described in JP-A-59-101651. Having been subjected to a hydrophilic treatment by undercoating of a water-soluble polymer having a group, JP-A-60-6435
Those colored with an acid dye described in JP-A No. 2 are particularly preferable. Other hydrophilic treatment methods include silicate electrodeposition described in U.S. Pat. No. 3,658,662. Further, after graining treatment and anodic oxidation, sealing treatment is preferable. Such a 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.

Further, the aluminum support may be undercoated. Examples of the compound used for the undercoat include carboxymethylcellulose, dextrin, gum arabic, phosphonic acids having an amino group such as 2-aminoethylphosphonic acid, phenylphosphonic acid optionally having a substituent, naphthylphosphonic acid, and alkylphosphonic acid. Acids, organic phosphonic acids such as glycerophosphonic acid, methylene diphosphonic acid and ethylene diphosphonic acid, organic phosphoric acids such as phenylphosphoric acid, naphthyl phosphoric acid, alkyl phosphoric acid and glycerophosphoric acid which may have a substituent, substituents Having organic groups such as phenylphosphinic acid, naphthylphosphinic acid, alkylphosphinic acid and glycerophosphinic acid, amino acids such as glycine and β-alanine, and hydroxyl groups 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 JP-A-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 the support on a support, and drying. Further, a yellow dye can be added for improving the tone reproducibility of the photosensitive lithographic printing plate. The coating amount of the undercoat layer after drying is suitably from ² to 200 mg / m ² , and preferably from 5 to 100 mg / m ² .

It is preferable to provide a mat layer composed of protrusions provided independently of each other on the photosensitive layer. The purpose of the mat layer is to improve the vacuum adhesion between the negative image film and the photosensitive lithographic printing plate in contact exposure, thereby shortening the vacuuming time and preventing the collapse of minute dots during exposure due to poor adhesion. That is. As a method for applying the mat layer, a method for thermally fusing powdered solid powder described in JP-A-55-12974 and a polymer-containing water described in JP-A-58-182636 are used. And drying. Any of these methods can be used. The mat layer is desirably composed of a substance which is dissolved in an aqueous developer substantially free of an organic solvent or which can be removed thereby. A photosensitive lithographic printing plate having a photosensitive composition layer coated and dried on a roughened aluminum plate is obtained by cutting the opposing two or four edges into the shape of the present invention, After the surface is desensitized, the image is exposed to light and developed with an aqueous alkaline solution to obtain a relief image. Light sources suitable for exposure include carbon arc lamps, mercury lamps, xenon lamps, metal halide lamps, strobes, ultraviolet rays, laser beams and the like.

An aqueous alkaline solution-based developer used for developing a negative photosensitive lithographic printing plate is disclosed in JP-A-51-774.
No. 01, No. 51-80228, No. 53-44202 and Nos. 55-52054, each having a pH of 8 to 13 and containing 75% by weight or more of water. Are preferred. If necessary, an organic solvent (benzyl alcohol, ethylene glycol monophenyl ether) having a solubility in water of 10% by weight or less at room temperature, an alkali agent (triethanolamine, diethanolamine, monoethanolamine, sodium phosphate, sodium carbonate), anionic surface activity Agents (aromatic sulfonate, dialkyl sulfosuccinate, alkyl naphthalene sulfonate, fatty acid salt, alkyl sulfate salt),
Nonionic surfactants (polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether,
A polyoxyethylene polyoxypropylene block polymer), a stain inhibitor (sodium sulfite, sodium salt of sulfopyrazolone) and a water softener (tetrasodium ethylenediaminetetraacetate, trisodium nitrotriacetate) can be added. However, if organic solvents are contained, toxicity during work, hygiene problems such as odor, fire,
Since there is a problem of safety such as gas explosion, a problem of workability such as generation of bubbles, a problem of pollution by waste liquid, a problem of cost, and the like, those containing substantially no organic solvent are more preferable. Examples of such an aqueous alkaline developer containing substantially no organic solvent include, for example, JP-A-59-84241, JP-A-57-192952 and JP-A-62-22633.
JP-A No. 6-264, etc., a developer composition used when developing a positive-working lithographic printing plate after image exposure to light can be used.

The photosensitive lithographic printing plate of the present invention is disclosed in
-8002, 55-115045 and 59-58
The plate-making process may be performed by the method described in each of the publications of No. 431. That is, after the development treatment, the plate surface protection treatment may be performed after washing with water, or the plate surface protection treatment as it is, a treatment with an aqueous solution containing an acid, or a treatment with an aqueous solution containing an acid, followed by a plate surface protection treatment. Further, in the development process of this type of photosensitive lithographic printing plate, the alkali aqueous solution is consumed depending on the processing amount, and the alkali concentration is reduced. The performance is reduced.
The processing capacity may be restored by using a replenisher as described in JP-A-2004-2004. In this case, US Pat. No. 4,882,2
It is preferable to replenish by the method described in No. 46. The plate making process described above is disclosed in Japanese Patent Application Laid-Open No. 2-705.
It is preferably carried out using an automatic developing machine as described in JP-A Nos. 4 and 2-32357. Examples of the plate surface protective agent applied as required in the final step of the plate making process include JP-B-62-16834, JP-B-62-25118, and JP-B-62-25118.
3-52600, JP-A-62-7595 and JP-A-62-7595
Those described in JP-A-11693 and JP-A-62-83194 are preferable. After the processing with the developing solution, if necessary, unnecessary portions of the image area can be erased with a commercially available negative erasing solution or rubbed with a stone stick.

The developer used for developing the positive photosensitive lithographic printing plate is preferably an alkaline aqueous solution containing substantially no organic solvent, and specific examples thereof include sodium silicate, potassium silicate, sodium hydroxide, and hydroxide. Potassium, lithium hydroxide, sodium phosphate tribasic, sodium phosphate dibasic, ammonium phosphate tribasic, ammonium phosphate dibasic, 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% by weight, preferably 0.5-5% by weight. Among these, potassium silicate, lithium silicate, a developer containing an alkali silicate such as sodium silicate is preferable because stains during printing hardly occur,
When the composition of the alkali silicate is [SiO ₂ ] / [M] = 0.
5 to 2.5 (where [SiO ₂ ] and [M] indicate the molar concentration of SiO _{2 and} the molar concentration of the total alkali metal, respectively) and contain 0.8 to 8% by weight of SiO ₂ . Developing solution is preferably used. In addition, water-soluble sulfites such as sodium sulfite, potassium sulfite, and magnesium sulfite, resorcin, methylresorcin, hydroquinone, thiosalicylic acid, and the like can be added to the developer. The content of these compounds in the developer is preferably 0.002 to 4% by weight, and more preferably 0.01 to 1% by weight.

Further, in a developer, JP-A-50-51324 is used.
JP-A-59-84241 and JP-A-59-84241 and JP-A-59-75255, JP-A-60-111246 and JP-A-60-213943. Or at least one of the nonionic surfactants described in JP-A-55-95946 and JP-A-56-142528. Is preferably used because it can increase the wettability to the photosensitive composition and the development stability (development latitude). The addition amount of such a surfactant 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 in all the alkali metals, since the generation of insolubles in the developer is small, and more preferably 9%.
0 mol% or more, most preferably 100 mol% of potassium
Is the case.

Further, the developing solution used in the present invention may contain some organic solvents such as alcohols and
Chelating agent described in Japanese Patent Publication No. 1-301
An antifoaming 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 further described in JP-A-54-8002,
Needless to say, the plate-making process may be performed by the methods described in JP-A-55-115045 and JP-A-59-58431. That is, after the development treatment, the plate surface protection treatment may be performed after washing with water, or the plate surface protection treatment as it is, the treatment with an aqueous solution containing an acid, or the plate surface protection treatment after the treatment with an aqueous solution containing an acid. Furthermore, in the development process of this type of photosensitive lithographic printing plate, the alkali aqueous solution is consumed depending on the processing amount, and the alkali concentration is reduced, or the alkali concentration is reduced by air due to long-time operation of the automatic developing solution. Although the processing capacity is reduced, the processing capacity may be restored by using a replenisher as described in JP-A-54-62004. In this case, U.S. Pat.
It is preferred to replenish by the method described in 2,246. Further, the plate making process as described above is disclosed in Japanese Patent Laid-Open No. 2-70.
It is preferably carried out using an automatic developing machine as described in JP-A Nos. 54 and 2-32357.

In the case where the photosensitive lithographic printing plate of the present invention is subjected to image exposure, development, washing or rinsing, and then unnecessary image portions are erased, it is described in JP-B-2-13293. It is preferable to use such an erasing liquid. Further, as a plate surface protective agent which is optionally applied in the final step of the plate making step, JP-B-62-16834,
Nos. 2-25118 and 63-52600;
No.-7595, No.62-11693, No.62-831
What is described in each gazette of No. 94 is preferable. Furthermore, when the photosensitive lithographic printing plate of the present invention is subjected to image exposure, development, washing or rinsing, erasing if desired, and burning after washing with water, before burning, Japanese Patent Publication No. 61-2518 is used. And JP-A-55-28062, JP-A-62-31859, and JP-A-61-159655.

Synthesis Example 1 4-diazodiphenylamine sulfate (purity 99.5%) 2
9.4 g at 25 ° C. were slowly added to 70 ml of 96% sulfuric acid 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 a condensation reaction to proceed. The condensation molar ratio between the diazo compound and formaldehyde is 1: 1. While stirring the reaction product,
The mixture was poured into 2 liters of ice water and treated with a cold concentrated aqueous solution in which 130 g of sodium chloride was dissolved. The precipitate is filtered off with suction.
The recovered, partially dried solid is dissolved in 1 liter of water, filtered, cooled with ice and washed with potassium hexafluorophosphate 2
The solution was treated with an aqueous solution in which 3 g was dissolved. The precipitate was collected by filtration and air-dried to obtain 30.3 g of the high molecular weight diazo compound (1).
I 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 the dye (using a low angle light scattering photometer) is 16,500.
Which corresponded to about 45-mers. The molecular weight distribution of this dye was measured by gel permeation chromatography (GPC).
0 mol% was contained.

[0038]

Next, the present invention will be described by way of examples. Example 1 Thickness of a JIS A1050 aluminum material containing 99.5% by weight of aluminum, 0.01% by weight of copper, 0.03% by weight of titanium, 0.3% by weight of iron, and 0.1% by weight of silicon. .3
The surface of a 0 mm rolled plate is grained using a 400 mesh 20% aqueous suspension of pamistone (manufactured by Kyoritsu Ceramics) and a rotating nylon brush (6,10-nylon), and then thoroughly washed with water. did. This was immersed in a 15% by weight aqueous sodium hydroxide solution (containing 4.5% by weight of aluminum), etched so that the amount of aluminum dissolved was 5 g / m ² , and washed with running water. Further, the mixture was neutralized with 1% by weight nitric acid, and then a 0.7% by weight aqueous nitric acid solution (aluminum)
0.5% by weight), a rectangular alternating voltage having a voltage at the anode of 10.5 volts and a voltage at the cathode of 9.3 volts (current ratio r = 0.
90, was subjected to electrolytic surface roughening treatment in an anode electricity quantity of 160 coulomb / dm ² using a current waveform) disclosed in Japanese Example No. Sho 58-5796. After washing with water,
It was immersed in a 0% by weight aqueous sodium hydroxide solution, etched so that the amount of aluminum dissolved was 1 g / m ² , and washed with water. Next, it was immersed in a 50% by weight aqueous solution of 30% by weight sulfuric acid, desmutted, and washed with water.

Further, a porous anodic oxide film was formed in a 20% by weight aqueous sulfuric acid solution (containing 0.8% by weight of aluminum) at 35 ° C. using a direct current. That is, electrolysis was performed at a current density of 13 A / dm ² , and the weight of the anodic oxide film was adjusted to 2.7 g / m ² by adjusting the electrolysis time. To prepare a negative photosensitive lithographic printing plate using a diazo resin and a binder, the 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 had a reflection density of 0.30 measured with a Macbeth RD920 reflection densitometer.
And the center line average roughness was 0.58 μm. Next, methyl methacrylate / ethyl acrylate / 2
-Acrylamide-2-methylpropanesulfonic acid sodium copolymer (average molecular weight: about 60,000) (molar ratio: 50/3)
(0/20) was applied by a roll coater such that the coating amount after drying was 0.05 g / m ² . Further, Photosensitive Solution 1 shown below 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 .

Photosensitive solution-1 Diazo resin of Synthesis Example 1 0.50 g Binder-1 5.00 g Stylite HS-2 (manufactured by Daido Kogyo Co., Ltd.) 0.10 g Victoria Pureable-BOH 0.15 g Tricresyl phosphate 0 .50 g dipicolinic acid 0.20 g FC-430 (surfactant manufactured by 3M) 0.05 g solvent 1-methoxy-2-propanol 25.00 g methyl lactate 12.00 g methanol 30.00 g methyl ethyl ketone 30.00 g water 3.00 g

Binder-1 was 2-hydroxyethyl methacrylate / acrylonitrile / methyl methacrylate / methacrylic acid copolymer (weight ratio 50/20/26 /
4. A water-insoluble, alkali-water-soluble film-forming polymer having an average molecular weight of 75,000 and an acid content of 0.4 meq / g). Stylite HS-2 (manufactured by Daido Kogyo Co., Ltd.) is a polymer compound having higher oil sensitivity than a binder, and styrene / mono-4-methyl-2-pentyl maleate = 50/50 (molar ratio). )), And had an average molecular weight of about 100,000. Obtained in this way
Using a slitter device of FIG. 1 and a cutting blade of FIG. 2, a gap (D) between an upper cutting blade and a lower cutting blade is formed on a 0.3 mm, 800 mm wide coil-shaped photosensitive lithographic printing plate with a width of 796 mm. 50 μm
And the amount of engagement between the upper and lower cutting blades (S)
Was set to 300 μm, and slits were continuously formed in a shape such that the cutting sag height was 60 μm as shown in FIG. The notch area (Y) of this plate was 4000 μm ² . The curved surface of this plate had a hydrophilic surface over the entire surface. Thereafter, as a desensitizing liquid, an aqueous solution of 5 g of sodium hexametaphosphate and 95 g of pure water was continuously applied to the curved surface of the curved aluminum support with a Molton roll so that the dry weight was 0.1 g / m ^2. It was cut continuously to 560 mm in length, and 1000 sheets were stacked and packed.

After one week, the cut sheet-shaped photosensitive lithographic printing plate was image-exposed, and DN-3C (Fuji Photo Film Co., Ltd. alkaline aqueous solution) was applied with 800H (Fuji Photo Film Co., Ltd. automatic developing machine). (Development solution) 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 printing plate was printed 100,000 the following day on a rotary offset press using newspaper ink of Sakata Ink Co., Ltd. and Toyo Alky dampening water of Toyo Ink Co., Ltd.
20,000 sheets were printed at a speed of sheets / hour. No stain occurred on the printing paper surface corresponding to the edge of the printing plate.

Examples 2 to 7 0.3 mm in thickness and 800 mm in width obtained in the same manner as in Example 1.
The slit (D) μm between the upper cutting blade and the lower cutting blade is 30 to 100 μm using the slitter device of FIG. 1 and the cutting blade of FIG. And the biting amount (S) μm is changed between 200 and 800 μm, and the cutting sag height as shown in FIG.
The slits were continuously formed into a shape having a size of １００100 μm. At this time, the curved surface at the end of each plate had a hydrophilic surface over the entire surface. The numbers and conditions of the examples are shown in Table 1, and the sag height (X) μm of the obtained plate is shown.
And the area (Y) μm ² of the notch. Then, Example 1
In the same manner as in Example 1, the desensitizing liquid was applied to the curved surface of the aluminum support, and plate-making and printing were performed in the same manner as in Example 1. In any case, no stain was generated on the printing paper surface corresponding to the edge of the printing plate.

[0044]

Table 1 Example 2 3 4 5 6 7 Clearance between blades (D) μm 30 70 100 50 50 50 Biting amount (S) μm 300 300 300 200 500 800 Dropping height (X) μm 30 70 100 60 60 60 Notch area (Y) μm ² 600 8000 18000 3000 5000 6000

Examples 8 to 17 In the same manner as in Example 1, a coiled photosensitive lithographic printing plate was prepared, and was formed so as to have the same end portion shape as in Example 1 and to have a hydrophilic surface over the entire curved surface. Continuous slitting. Thereafter, the desensitizing liquid shown in Table 2 was applied to the curved surface of the aluminum support, and the plate was made and printed in the same manner as in Example 1. In each case, no stain occurred on the printing paper surface corresponding to the edge of the printing plate.

[0046]

[Table 2] Example End-face coating liquid Dry coating amount 8 Sodium hexametaphosphate 1 (g) 0.02 (g / m ² ) Pure water 999 Sodium hexametaphosphate 20 (g) 0.40 (g / m ² ) Pure water 80 10 Sodium hexametaphosphate 5 ( g) 0.10 (g / m ² ) pure water 94 phosphoric acid (85% by weight aqueous solution) 1 11 sodium hexametaphosphate 5 (g) 0.30 (g / m ² ) pure water 85 phosphoric acid (85% by weight aqueous solution) 10 12 fitin Acid (30% by weight aqueous solution) 3 (g) 0.02 (g / m ² ) Pure water 97 13 Phytic acid (30% by weight aqueous solution) 15 (g) 0.10 (g / m ² ) Pure water 85 14 Arabic gum (30% by weight) Aqueous solution) 3 (g) 0.02 (g / m ² ) pure water 97 15 Arabic gum (30% by weight aqueous solution) 15 (g) 0.10 (g / m ² ) pure water 85 16 sodium hexametaphosphate 5 (g) 0.15 (g / m ² ) m ²⁾ pure water 91 phosphoric acid (85 wt% aqueous solution) 1 gum arabic (30 wt% aqueous solution) 3 7 phytic acid (30 wt% aqueous solution) 15 (g) 0.12 (g / m 2) Pure water 82 gum arabic (30 wt% aqueous solution) 3

Comparative Example 1 In the same manner as in Example 1, the photosensitive layer was coated and dried, and a coil-shaped photosensitive lithographic printing plate slit to 796 mm was prepared.
The slit was continuously formed in the same manner as in the above. Comparative Example 1 was prepared without applying the desensitizing solution of Example 1. Then, Example 1
Plate-making and printing were performed in the same manner as described above. In Comparative Example 1, a thin linear stain occurred on the printing paper surface corresponding to the edge of the printing plate. In particular, dark linear stains were generated under the conditions where the dampening water amount was reduced, the ink amount was increased, and the dampening water amount was reduced and the ink amount was increased.

Comparative Example 2 In the same manner as in Example 1, a coiled photosensitive lithographic printing plate was prepared, and the gap and bite amount (0 and 300 μm, respectively) between the conventional upper cutting blade and lower cutting blade were set. A coil-shaped photosensitive lithographic printing plate was continuously slit to obtain Comparative Example 2. The end shape at this time was almost a right angle. Thereafter, the desensitizing solution described in Example 1 was applied to the end of the aluminum support, and the plate was made and printed in the same manner as in Example 1. A thin linear stain occurred on the printing paper surface corresponding to the edge.

As is clear from the above examples, in the printing plate manufactured from the photosensitive lithographic printing plate of the present invention, no stain occurs on the printing paper surface corresponding to the edge.

[Brief description of the drawings]

FIG. 1 is a diagram showing a slitter device.

FIG. 2 is a sectional view of a cutting portion of the slitter device.

FIG. 3 is an enlarged view of a portion A in FIG. 2;

FIG. 4 shows an end shape of the first embodiment.

[Explanation of symbols]

 10 (10a, 10b) ... upper cutting blade 11 ... rotating shaft 20 (20a, 20b) ... lower cutting blade 21 ... rotating shaft 30 ... aluminum sheet

Claims (1)

[Claims] 1. A photosensitive lithographic printing plate wherein a photosensitive layer is provided on an aluminum support having a hydrophilic surface, wherein the upper surface of at least two opposite ends of the aluminum support is hydrophilized over the entire surface. A photosensitive lithographic printing plate, characterized in that the curved surface is an upwardly convex curved surface, and the curved surface is subjected to a desensitization treatment.