JPH02230247A - Photosensitive planographic printing plate - Google Patents

Abstract

PURPOSE:To allow the complete erasing of the traces of mounting even with an erasing liquid which does not contain hydrofluoric acid so that ink does not stick to a part subjected to a burning treatment by providing a positive type photosensitive compsn. contg. a specific photosensitive material and an alkaline soluble resin by coating on an anodic oxidated aluminum sheet. CONSTITUTION:The positive type photosensitive resin compsn. contg. the photosensitive material expressed by formula I and the alkaline soluble resin is provided by coating on the aluminum sheet subjected to a sand graining treatment and anodic oxidation treatment. In the formula I, R1 to R8 denote hydrogen, hydroxyl group, halogen, etc.; R9 to R12 denote hydrogen or lower alkyl group; Z exhibits oxygen or single bond, where at least one among R1 to R8 denotes -OD or (R denotes hydrogen, alkyl group; D denotes 1,2-naphthoquinone diazide-5- sulfonyl group, etc.). The traces of tape sticking are completely erased even with the erasing liquid which does not contain the hydrofluoric acid and the sticking of the ink to the part subjected to the burning treatment is prevented.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a solid-type lithographic printing plate, and more particularly, to a positive-type lithographic printing plate containing a naphthoquinonediazide compound, it is mainly used to improve the erasability of pasting marks. Regarding improvements.

<Prior Art and Problems to be Solved> Aluminum plates are widely used as supports for lithographic printing plates. The aluminum plate is surface-treated to improve hydrophilicity, water retention, adhesion to the image area, and strength of the non-image area.

These surface treatment methods include ball graining, wire graining, and brush graining, which roughen the surface mechanically, and electrolytic roughening methods, which roughen the surface electrolytically using direct current or alternating current in a hydrochloric acid bath, nitric acid bath, etc. A surface roughening method that combines the following methods is being used. After this surface treatment, anodization treatment is performed in a sulfuric acid or phosphoric acid bath.

Furthermore, the material may be sealed with silicate or hot water, or immersed in polyvinylphosphonic acid.

A photosensitive composition mainly composed of novolac resin, vinyl resin, urethane resin, etc. as a binder is coated onto the aluminum support thus prepared using O-naphthoquinone diazide as a photosensitive substance. It is well known that photosensitive lithographic printing plates are made by

By using an O-naphthoquinonediazide compound, which is a polyhydroxy compound, as the O-naphthoquinonediazide compound, precipitation of crystals in the photosensitive layer is prevented, storage stability is improved, and adhesion with the aluminum support is improved. It is also already known to improve the properties, processing chemical resistance, developability, etc.

For example, as described in Japanese Patent Publication No. Sho 43-28403, those using ○-naphthoquinonediazide sulfonic acid ester of polycondensation resin of pyrogallol and acetone, for example, Japanese Patent Application Laid-open No. Sho 55-76346. As described in the publications, the developability is controlled using 0-naphthoquinonediazide sulfonic acid ester of a polycondensation resin of a mixture of pyrogallol and resorcin and acetone, for example, JP-A-50-1044, Same 5
As described in Japanese Patent No. 0-1045, an attempt has been made to improve the developability and processing chemical resistance using a polycondensation resin of polyhydric phenol, benzaldehyde, and acetaldehyde.

However, as a result of various studies using 0-naphthoquinonediazide sulfonic acid esters of polycondensation resins of ketones or aldehydes of these polyhydroxyphenols, the following problems have become clear.

In general, the method of creating a positive planographic printing plate is to create a single sheet of positive film by pasting various patterns and text onto a base, and then apply this film to the photosensitive layer of the planographic printing plate material. The printing plate is then exposed to ultraviolet light and then developed with a developer to form a printing plate. At this time, if even higher printing durability is desired, the photosensitive layer in the image area is thermally hardened by a burning process. However, when the above-mentioned positive film is applied to a conventional photosensitive layer made of 0-naphthoquinonediazide sulfonic acid ester of polycondensation resin of polyhydroxyphenol ketone or aldehyde and exposed, various films pasted on the positive original used are Although the edges of the base are not as strong as the image areas, the exposed photosensitive layer remains on the plate surface in a semi-exposed state, and this is strongly adhered to the plate surface and is easily removed by the developer. remains without being removed. When printing using this plate, stains occur on the printed matter. The pasting marks thus generated cannot be completely erased with a so-called non-polluting erasing liquid (does not contain hydrofluoric acid, a powerful chemical) which is generally used for positive planographic printing plates. the result,
In actual printing, problems such as fading of printed matter occur. The pasting marks mentioned above will appear when the burning process is performed to improve stiffness, which is commonly done.
This has become more noticeable and has become unbearable for actual printing use.

Furthermore, when conventional polyhydroxyphenol ketone or aldehyde polycondensation resin 0-naphthoquinonediazide sulfonic acid ester is used in the photosensitive layer, for example, JP-A-56
There was also the problem that it was not possible to increase the so-called dot reduction effect, which reproduces the halftone dot area on the printing plate to a smaller size, as described in Japanese Patent No. 162693, and the effective sensitivity could not be increased. If the dot reduction effect is not expected to be large as described above, the halftone dots on the printing plate will become large, making it impossible to produce clear printed matter. Furthermore, when using the conventional resin material mentioned above, the developability, especially with respect to the developer used, i.e., a fatigued developer, is not necessarily good, and if this is poor, the photosensitive material may remain in the non-image area where the photosensitive layer has been removed. However, since it has an affinity for ink, ink tends to adhere to it, resulting in stains on printed matter. Furthermore, when using the conventional resin material mentioned above, the visible image performance is often improved by fading the dye contained in the photosensitive layer in the exposed image to clearly indicate the position of the film pasted on a single film. The problem was that I couldn't expect anything.

In view of the above, it has been desired to improve the photosensitive layer using ○-naphthoquinonediazide sulfonic acid ester, which is a polycondensate of a ketone or aldehyde of polyhydroxyphenol, to solve the above-mentioned problems.

Therefore, an object of the present invention is to provide a positive photosensitive lithographic printing plate that can completely erase pasting marks even with an erasing solution that does not contain hydrofluoric acid, and that does not leave ink on those areas even when subjected to burning treatment. Our goal is to provide the following.

As a result of intensive research to achieve the above object, the present inventors prepared a photosensitive material having a structure represented by the following component: General formula: [A] on a grained and anodized aluminum plate. The present invention relates to a photosensitive lithographic printing plate coated with a positive type photosensitive resin composition containing: and an alkali-soluble resin.

In the above general formula CAE, R, %R. The halogens are preferably chlorine, bromine, and iodine, and the alkyl groups of R, ~R, are methyl, etinopep, n-butyl, isobutyl, sec-butyl, t-
An alkyl group having 1 to 4 carbon atoms such as butyl is preferable,
The alkoxy group is preferably an alkoxy group having 1 to 4 carbon atoms such as methoxy, ethoxy, hydroxyethoxy, bropoxy, hydroxypropoxy, imbroboxy, n-butoxy, isobutoxy, sec-butoxy, or t-butoxy, and the aralkyl group is preferably benzyl. A phenyl group, a penzhydryl group, etc. are preferable, and the aryl group is preferably phenyl, tolyl, hydroxypheninopenaphthyl, etc., and the monoalkylamino group is monomethylamino, monoethylamino, monobropylamino, monoisobrobyl. Monoalkylamino groups having 1 to 4 carbon atoms such as amine, mono-n-butylamino, monoisobutylamino, mono-sec-butylamino, and mono-t-butylamino are preferable, and the dialkylamino groups include dimethylamino, diethylamine, and dipropyl. amino, di-isopropylamino, di-n-butylamino, di-isobutylamino, di-sec-butylamino,
Each carbon number is 1 to 1, such as di-t-butylamino.
Seven dialkylamino groups having 4 alkyl substituents are preferred, and examples of the acylamino group include acetylamino, probionylamino, butyrylamino, imbutyrylamino,
Aliphatic substituted acylamino groups each having 2 to 5 carbon atoms, such as invalerylamino, pivaloylamino, and valerylamino, and aromatic substituted acylamino groups, such as penzoylamino and toluoylamino, are preferable, and the alkylcarbamoyl group and the citrate are methyl. Alwyl carbamoyl group having 2 to 5 carbon atoms, such as ethylcarbamoyl, ethylcarbamoinopebrovir, isoprobil, isoprobil, n-butylcarbamoinopeisobutyl, sec-butylcarbamoyl, and t-butylcarbamoyl. are preferable, and the arylcarbamoyl group is preferably phenylcarbamoyl, tolylbamoyl, etc., and the alkylsulfamoyl group is methylsulfamoyl, ethylsulfamoyl/l, =, probylsulfamoyl, isobrobylsulfamoyl, etc. Famoyl, n-butylsulfamoyl, SeC-butylsulfamoyl, t-
Alkylsulfamoyl groups having 1 to 4 carbon atoms such as butylsulfamoyl are preferable, and arylsulfamoyl groups are preferably phenylsulfamoyl, tolylsulfamoyl, etc., and the acyl group is preferably forminosulfamoyl. Pacetyl, propionyl, butyryl? 1 to 5 carbon atoms such as sobutyryl, valerinopeisovaleryl, bivaloyl
Aliphatic acyl groups and aromatic acyl groups such as benzoyl, toluinopesaliti-inobenaphthoyl are preferred, and the alkyloxycarbonyl groups include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, improboxycarbonyl, Preferred are alkyloxycarbonyl groups having 2 to 5 carbon atoms such as n-butoxycarbonyl, sec-butoxycarbonyl, and t-butoxycarbonyl; examples of aryloxycarbonyl groups include phenoxycarbonyl groups; An aryloxycarbonyl group is preferable, and the measiloxy group has 2 to 5 carbon atoms, such as acetoxy, probionyloxy, butyryloxy, imbutyryloxy, valeryloxy, isovaleryloxy, and bivaloyloxy.
Aliphatic acyloxy groups and aromatic acyloxy groups such as penzoyloxy, toluoyloxy, naphthoyloxy are preferred.

In the above general formula (A), the alkyl group represented by R and ~R1 is preferably an alkyl group having 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and sec-butinopet-t-butyl. .

The compound represented by the general formula [A] is a derivative of subibindane or spiropeichroman represented by the general formula: and 1,2-naphthovinonediazide-5
It can be easily synthesized by condensing with -sulfonyl chloride, 1,2-naphthoquinonediazide-4-sulfonyl chloride, or a mixture thereof.

The compound represented by the general formula CB used here is:
For example, the method of W, Baker et al. CJ, Chem,
Soc, , (1939) p195~].

Specific examples of the compound represented by the general formula [B] include the following compounds.

3,3.3',3'-tetramethyl-1,1'-spirobiindane-4.6,7.4'. 6'7'-Hekinobe 3, 3.3'. 3'-tetramethyl-1,1'spirobiindane-5.6,7.5',6'7'-hexol, 3,3.3'. 3'-tetramethyl-1,1'spirobyindan-5.6.5',6'-tetrol, 3,3.3',3'-tetramethyl-1,1'spirobyindan-6.7 .6'. 7'-tetrol, 5.5'-di-t-butyl-3.3.3'. 3'-tetramethyl-1.1'-spirobiindane-6.7.6
'． 7'-tetrol, 5-t-butyl 3.3.3'
, 3'-tetramethyl-1,1'-spirobiindane-6,7,6'. 7'-tetrol, 3.3.3'. 3'-tetramethyl-1,1'spirobiindane-5.6.6'-}liol, 3. 3. 3'. 3'-tetramethyl-l,
1'7'-1hexamethyl-2,2'-subiropechroman-6,6'-diol, 6,6'-t-butyl-4,4,4'. 4'-Tetramethyl-2,2'-spiropechroman-7,7'-diol However, the compound is not limited to these compounds.

A conventional method is used for the esterification reaction between the compound of general formula CB) and 1,2-naphthoquinonediazide-5-sulfonyl chloride or 1,2-naphthoquinonediazide-4-sulfonyl chloride. That is, a predetermined amount of spirobiindane or spiropychroman represented by the general formula CB], 1,2-naphthoquinonediazide-5-sulfonyl chloride or 1,2-naphthoquinonediazide-4-sulfonyl chloride, and dioxane, acetone, methyl ethyl ketone, etc. Pour the solvent into the flask,
A basic catalyst such as sodium hydroxide, sodium carbonate, sodium hydrogen carbonate, triethylamine, etc. is added dropwise to cause condensation. The obtained product is purified and dried after washing with water. A photosensitive substance represented by the general formula [A] can be prepared by the above method.

In the photosensitive substance represented by the general formula CAE, the total number of 10-D and 1N-D contained in each molecule of R is preferably 2 or more, particularly 4 or more.

Specific examples of the photosensitive substance represented by the general formula (Al) include the following substances.

3.3.3'. 1,2-naphthoquinonediazide-5-sulfonic acid hexaester 3,3.3' of 3'-tetramethyl-1,1'subibidane-5.6,7.5',6'7'-heysol. 3'-tetramethyl-1,1'spirobiindane-5.6,7.5'. 1,2-naphthoquinonediazide-5-sulfonic acid penc ester of 6'7'-hexol 3,3.3'. 3'-tetramethyl-1.1'subirobindan-5.6,7.5'. 1,2-naphthoquinonediazide-5-sulfonic acid tetraester of 6'7'-hexol 3,3.3'. 3'-tetramethyl-1,1'subibidane-5.6,7.5',6'7'-heysol 1,2-naphthodinonediazide-5-sulfonic acid triester 3.3.3 '． 1,2-naphthoquinonediazide-5-sulfonic acid diester of 3'-tetramethyl-1,1'subibidane-5.6.7.5',6'7'-hexol 3.3.3'. 3'-Tetramethyl-1.1'Subirobiindane-5.6.7.5'. 1,2-naphthoquinonediazide-5-sulfonic acid monoester of 6'7'-hexol 3,3.3',3'-tetramethyl-1,1'spirobeindan-4.6.7.4'. 1,2-naphthoquinonediazide-5-sulfonic acid hexaester of 6'7'-hexol 3,3.3',3'-tetramethyl-1.1'spirobeindan-4.6,7.4', 1,2-naphthoquinonediazide-5-sulfonic acid tetraester of 6'7'-hexol 3,3.3'. 3'-Tetramethyl-1.1'Subirobiindane-4.6,7.4'. 1,2-naphthoquinonediazide-5-sulfonic acid triester of 6'7'-hexol However, the present invention is not limited to these materials.

As the alkali-soluble resin used in the present invention, novolak resin is mainly used, but vinyl phenol resin, styrene-acrylic acid copolymer, methyl methacrylate-methacrylic acid copolymer, methyl methacrylate-methacrylic acid copolymer, etc. Polymers, alkali-soluble polyurethane resins, alkali-soluble polybutyral resins, etc. may be used in combination.

Additionally, U.S. Patent No. 4. 1.23. As described in the specification of No. 279, in addition to the above resins, phenol or cresol substituted with an alkyl group having 3 to 8 carbon atoms such as t-butylphenol formaldehyde resin and n-octylphenol formaldehyde resin are used. A metal shrinkage product with formaldehyde may be used in combination.

The mixing ratio of the quinonediazide compound to the alkali-soluble resin is suitably in the range of 50:50 to 15:85 by weight, preferably in the range of 40:60 to 20:ao.

The positive photosensitive composition according to the present invention may further contain other dyes, pigments, plasticizers, etc., if necessary. Other suitable dyes include oil-soluble dyes and basic dyes. Specifically, oil yellow #101, oil yellow #130, oil pink #312, oil green BG, oil blue BOS, oil blue #60
3. Oil Black BY, Oil Black BS, Oil Black T-505 (manufactured by Orient Chemical Industry Co., Ltd.), Crystal Violet (CI42555),
Methyl violet (CI42435), rhodamine B (CI45170B), malachite green (CI42000), methylene blue (CI5201)
5), etc. Such dyes can be contained in an amount of 1% by weight or less based on the total weight of the positive photosensitive composition according to the present invention.

The positive photosensitive composition according to the present invention is coated on a desired support after being dissolved in a solvent that dissolves each of the above components. The solvents used here include ethylene dichloride, cyclohexanone, methyl ethyl ketone, ethylene glyco
-monomethyl ether, ethylene glycol monoethyl ether, 2-methoxyethyl acetate, toluene, ethyl acetate, brobylene glycol monomethyl ether acetate, propylene glycol methyletherenopedimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethyl Examples include acetamide and methyl lactate, and these solvents can be used alone or in combination. The concentration (solid content) of the above components is 2 to 50% by weight. The coating amount varies depending on the application, but for example, for photosensitive planographic printing plates, the solid content is generally 0.5 to 0.
7 g/ms is suitable, preferably 1.5-3 g
/ m” range.

The positive type photosensitive composition according to the present invention includes a compound that generates an acid that changes the hue of the dye when exposed to light, in order to improve the visual contrast after exposure.
For example, U.S. Patent No. 3. 969. 0-naphthoquinonediazide-4-sulfoyl chloride as described in U.S. Patent No. 4.118; 212. 97
2-styryl-5- as described in specification no.
Trihalomethyl-1. 3. 4-oxazole,
U.S. Patent No. 3. It is preferable to add a vinyl trihalomethyl-S-}riazine compound as described in No. 987,037.

Further, in order to improve the coating area, it is preferable to contain a fluorine-based surfactant or the like.

Furthermore, as other additives, JP-A-5-2-8 002
A small amount of the cyclic acid anhydride described in No. 2 may be added.

When applying a positive photosensitive composition to a lithographic printing plate,
A photosensitive composition is applied onto the support.

As the support for such a positive type PS plate, any material having a hydrophilic surface can be used, including various materials conventionally usable as supports for lithographic printing plates, but aluminum plates are particularly preferred. Suitable aluminum plates include pure aluminum plates and aluminum alloy plates, as well as plastic films laminated or vapor-deposited with aluminum. The surface of the aluminum plate is preferably subjected to a surface treatment such as graining treatment, immersion treatment in an aqueous solution of sodium silicate, potassium fluorozirconate, phosphate, or the like, or anodization treatment. Also, after graining, U.S. Patent No. 2. 714.
Aluminum plate immersed in sodium silicate aqueous solution as described in specification No. 066, Japanese Patent Publication No. 47-
As described in Japanese Patent Publication No. 5125, an aluminum plate is anodized, and then immersed in an aqueous solution of an alkali metal silicate. After that, those obtained by immersion treatment in an aqueous solution of polyvinylphosphonic acid are also suitably used. The above anodizing treatment can be carried out using an electrolytic solution, for example, of an aqueous or non-aqueous solution of an inorganic acid such as phosphoric acid, chromic acid, sulfuric acid, or boric acid, or an organic acid such as oxalic acid or sulfamic acid, or a salt thereof, or a combination of two or more thereof. It is carried out by passing an electric current through an aluminum plate inside.

Also, U.S. Pat. No. 3,658. Silicate electrodeposition as described in '662 is also effective.

Additionally, U.S. Patent No. 4. 087. Specification No. 341, Japanese Patent Publication No. 4 6-2 7 4 8 1, Japanese Patent Publication No. 5 2
It is also useful to use a support that has been subjected to electrolytic duplexing as disclosed in Japanese Patent No. 30503 and is anodized as described above. Additionally, U.S. Pat. No. 3,834.
Aluminum plates that are grained, chemically etched and then anodized as described in the '998 patent are also preferred.

The positive PS plate according to the present invention is produced by exposing the photosensitive layer to a light source rich in active light such as a carbon arc lamp, mercury lamp, metal halide lamp, or xenon lamp through a transparent original as in the past, and then developing it with a developer. The exposed areas are removed to expose the underlying hydrophilic surface of the support, yielding a lithographic printing plate. Preferred developing solutions include sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, tribasic sodium phosphate,
Inorganic alkaline agents such as dibasic sodium phosphate, dibasic sodium phosphate, dibasic potassium phosphate, dibasic ammonium phosphate, dibasic ammonium phosphate, sodium metasilicate, sodium bicarbonate, aqueous ammonia, etc., such as monoethanolamine, diethanolamine, etc. An alkaline aqueous solution containing at least one kind of alkali such as an organic alkaline agent such as U.S. Pat. 259. It is described in detail in the specification of No. 434.

The developing method can be carried out by various means such as an automatic developing machine having both a developing and gum section, a normal automatic developing machine having a water washing section, dish development, and manual development.

In the original film used as a manuscript, the edges of the film and the marks left by the tape are reproduced on the developed plate. Since these parts are unnecessary, they are usually erased with an eraser containing an organic solvent.

If you want to increase the printing durability, leave it for about 2 to 8 minutes at a high temperature of 200 to 300°C. After this, the plate surface is treated with a hydrophilic substance such as gum arabic.

Examples> Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these embodiments.

(1) Synthesis of photosensitive substance (a) Birogallol 42g 1 acetone 33g, acetic acid 80rnl
, and 64 mj' of concentrated hydrochloric acid into a three-necked flask,
It was uniformly dissolved under stirring. After heating in a water bath and refluxing for 24 hours, it was cooled to room temperature. After cooling, the reaction solution was dropped into 2000 m' of distilled water, and the product was precipitated and filtered, followed by drying under reduced pressure.

The obtained 3,3.3'3'-tetramethyl-1,
1'-Subibi Indan-5.6, 7.5'. 6'.
4 g of 7'-hexol, 13 g of 1,2-naphthoquinonediazide-5-sulfonyl chloride and 30 g of acetone
0- was charged into a three-necked flask and uniformly dissolved under stirring. Next, triethylamine/acetone = 4, 9g/3
0mj! The mixed solution was gradually added dropwise and reacted at room temperature for 3 hours. After the reaction was completed, the contents were dropped into a 1% aqueous hydrochloric acid solution, and the resulting precipitate was filtered off and dried under reduced pressure to obtain a photosensitive material (a).

(2) Synthesis of photosensitive substance Q)) Using pyrocaterol and acetone, in the same manner as for photosensitive substance (a), 3. 3'. 3'-Tetramethyl 1,1'-Subirobiindan-5,6.5
'． 6'-tetrol was obtained.

Obtained 3. 3. 3'. 3'-Tetramethyl-1,1'-Subirobiindane-5.6.5'. 6
'-tetrol 4 g, 1,2-naphthoquinone diazide 5-sulfonyl chloride 9.5 g and acetone 300 g
rnI! was charged into a three-necked flask and uniformly dissolved under stirring.

Then, triethylamine/acetone=3.6g/3
0mj! The mixed solution was gradually added dropwise and reacted at room temperature for 3 hours.

After the reaction was completed, the contents were dropped into a 1% aqueous hydrochloric acid solution, and the resulting precipitate was filtered off and dried under reduced pressure to obtain a photosensitive material (b).

Example 1 Thickness 0. The surface of a 24 m+n aluminum plate was grained using a nylon brush and a 400 mesh vamisu water suspension, and then thoroughly washed with water.

After etching by immersing it in a 10% sodium hydroxide aqueous solution at 50° C. for 20 seconds, it was washed with running water (20° C.) for 1 minute.

Next, using a 1.5% nitric acid aqueous solution, the voltage was 1 at 20°C.
Using 0V sine wave alternating current, electricity amount 900 clones/d
After carrying out electrochemical graining for 20 seconds at 70°C, the grains were desmutted by immersion in 20% phosphoric acid at 70°C for 30 seconds. 3.0g/m by DC voltage 22V
'' anodized film was provided.

The following photosensitive composition was coated on this support and dried to form a photosensitive layer having a dry weight of 2.5 g/m' to obtain a positive planographic printing plate.

Photosensitive composition: Photosensitive substance (a) 0. 8
gm, p-cresol formaldehyde resin (m:
p=6 0 + 4 0) 1.7 0
gp-t-butylphenol resin 0. 0 5
g Victoria Viewer Blue BOH 0.05g2
-Trichloromethyl-5-p0.06 g-Butoxystyryl-1,3,4-oxadiazole methyl ethyl ketone 12 g Propylene glycol methyl ester 18 g This positive working photosensitive lithographic printing plate was placed on a transparent base using a 3KW metal halide lamp as a light source. First, three sheets of positive film were exposed for 60 seconds through a document pasted with cellophane tape, and then exposed to light for 60 seconds using Fuji Photo Film developer, DP-4 (1:7
), and processed through an automatic processor containing a rinse liquid FR-2 (1:7). There were film edge marks and tape adhesion marks on the obtained plate, so I applied Fuji Photo Film's erasing liquid RP-1 to the brush, erased it, washed it with water, and applied Fuji Photo Film's gum GU-7. After treating the plate surface with a solution diluted twice with water and leaving it for one day, Heidel KO
Printed on an RD machine. The erased traces disappeared completely, and no ink adhered to them. In addition, after erasing and washing with water, the printing plate was wiped with Fuji Photo Film's Burning Surface Conditioning Liquid BC-3 and processed for 7 minutes at 260°C in a burning device BP-1300.The prints also had no traces left and were not smudged. .

On the other hand, as a comparison, Tokuko Sho 4 3-2 8 4 0 3
When the material described in Example 1 of the specification is used in place of the photosensitive material (a), the film is printed in the area where the film edge traces have been erased. Dirt appeared on the edge marks.

Example 2 In place of the photosensitive proboscis (a) in Example 1, a photosensitive substance (b) was used.
), no traces after erasing were seen on those printed after burning.

Claims (1)

[Claims] On an aluminum plate with a grained surface anodized, the following components are shown: General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [A] [R_1 to R_8; each independently hydrogen, Hydroxyl group, halogen, alkyl group, alkoxy group, aralkyl group, aryl group, amino group, monoalkylamino group, dialkylamino group, acylamino group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfamoyl group, arylsulfamoyl group , carboxyl group, cyano group, nitro group, acyl group, alkyloxycarbonyl group, aryloxycarbonyl group, acyloxy group or -OD, ▲Mathematical formula, chemical formula, table, etc.▼(
R represents hydrogen or an alkyl group, and D represents a 1,2-naphthoquinonediazide-5-sulfonyl group or a 1,2-naphthoquinonediazide-4-sulfonyl group). R_9 to R_1_2; Each independently hydrogen or lower alkyl group. Z: Oxygen or single bond. [However, at least one of R_1 to R_8 is -O
Represents D or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (R and D are as defined above). ] A photosensitive lithographic printing plate coated with a positive-working photosensitive resin composition containing a photosensitive substance having a structure represented by: and an alkali-soluble resin.