JPS58127939A - Wet type developer used for printing plate - Google Patents

Abstract

PURPOSE:To obtain a wet type developer for preparing a printing plate superior in alkali resisance, resolution, etc., by using as a binder, a quaternary copolymer of >=4C methacrylate, styrene or its derivative, <=3C methacrylate, and a monomer having an acid group. CONSTITUTION:(Component a) 5-60wt% (meth)acrylate; (Component b) 30- 90wt% styrene or styrene derivative; (Component c) 5-40wt% (meth)acrylate having <=3C alkyl; and (Component d) 1-15wt% monomer having an acid group are copolymerized and a toner used for a wet type developer is prepared by using this copolymer. An image is formed on a printing plate material with this toner by electrophotography, and nonimage areas are removed by etching to form a printing plate. This toner is good in dispersion stability and suitable for this process, and used for a wet type developer capable of forming a printing plate durable for long-time use and storage, and high in resolution and printing resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION A printing original plate having an organic photoconductive compound layer on a conductive substrate of the present invention is electrophotographically formed to form a toner image using a wet developer, and after fixing, an alkaline aqueous etching solution is applied. This invention relates to a wet developer used in a printing plate obtained by etching away non-image areas other than image areas.

As a photoreceptor for printing plates applying electrophotography, a photoreceptor is prepared by dispersing inorganic photoconductive powder such as zinc oxide or cadmium sulfide in a suitable binder and coating it on paper, film, or aluminum plate. known to be used. To form an image and use it as a printing plate, corona charging, exposure, and toner imaging are performed by electrophotography, and the developed toner image is receptive to oil-based printing ink, and the non-image area is hydrophilic. It is treated to make it hydrophilic and can be used as a printing plate. A toner image can be obtained using a dry type developer or a wet type developer, but the resolving power of a dry type developer is considerably inferior to that of a wet type developer, and therefore, a wet type developer is generally used.

However, in order to increase sensitivity, these printing plates coat a support with a large amount of inorganic photoconductive powder together with a binder, which has limitations in smoothness, film strength, and adhesion to the support. In addition, there are problems with maintaining hydrophilicity in non-image areas and film strength, so even though it is suitable for a short run printing plate of about 1000 sheets, it is not suitable for a long run printing plate of more than 100 sheets. be.

Many printing plates obtained by electrophotography using organic photoconductive compounds are also known; for example, Japanese Patent Publication No. 37-171
No. 62, No. 38-6961, No. 41-2426, No. 46-39405, JP-A-50-19509, No. 5
No. 0719510, No. 54-145538, No. 54-
No. 89801, No. 54-134632, No. 54198
No. 03, No. 55-105244, and the like.

These use styrene-maleic anhydride copolymer, vinyl acetate-crotonic acid copolymer, vinyl acetate-maleic anhydride copolymer, thunol resin, etc., which are soluble in alkali and/or alcohol, as a binder, and are organic photoconductive. A photoreceptor is a material coated with a compound on a conductive metal substrate such as an aluminum plate, and is used for corona charging, exposure,
A toner image is obtained by performing toner development.

Furthermore, by using the toner image as a resist layer and removing the non-image area other than the toner image by etching with an etching liquid mainly composed of alkali and/or alcohol, a printing plate is created in which the hydrophilic metal substrate is exposed in the non-image area. . This method has been put to practical use by Kaare under the trade name Elefasol. However, the Elefasol system is a system that forms toner images using a dry developer, and its resolution is poor. I can only get it.

On the other hand, if a toner image is formed using a wet developer, 15
An image having a resolution of about 20 lines/frame can be obtained. Toner images produced using dry developers have poor resolution because the toner particles are large, but since the amount of toner particles attached is large, it is difficult to remove non-image areas by etching with an etching solution containing alkali and/or alcohol as the main component. In many cases, the thick toner image acts as a resist layer, and the image area is rarely etched. Toner images produced using a wet developer have excellent resolution and can produce sharp images, but the thickness of the toner image is much thinner than a dry image (and its effectiveness as a resist layer is reduced.If a wet developer is used, it has excellent resolution. , a toner image is formed, but due to poor resistivity to etching liquid, the resolution of the printing plate after etching cannot maintain the same resolution as before etching.
As a result, it is difficult to obtain a printing plate with excellent resolution. Further, dispersion stability is a common problem with wet developers.

Wet type developers are made by dispersing resins, dyes or pigments, charge control agents, etc. in organic solvents with low dielectric constants and high electrical insulation properties, but because they are dispersions, dispersion stability is limited. It is a very important factor for wet type developers, and a great deal of effort is being made by wet type developer manufacturers.

In the present invention, a particularly difficult problem in producing a wet developer for forming a resist layer resistant to alkali is that if the developer resin composition is designed to improve dispersion stability, the resist layer against etching solutions will be resistant to alkali. However, if the resist properties are improved, the dispersion stability becomes inferior, which is a contradictory property.

The first object of the present invention is to provide the above-mentioned method for making a printing plate, comprising:
An object of the present invention is to provide a wet type developer that forms a toner image having strong resistivity against alkali. The second object is to provide the above-mentioned wet developer for printing plates which has excellent dispersion stability and can withstand long-term use and storage. A third object is to provide a wet development type printing plate having excellent resolution and high printing durability.

The object of the present invention is to use 05 to 100% as a resin component in a wet developer.
Acrylic ester or methacrylic ester having 60% by weight of an alkyl group having 4 or more carbon atoms and 03
0 to 90% by weight of styrene or derivatives of styrene and 0
This was achieved by using a copolymer composed of 5 to 40% by weight of an acrylic ester or methacrylic ester having an alkyl group having up to 3 carbon atoms and a monomer having 01 to 15% by weight of an acidic group. .

The resin composition of the wet developer for printing plates of the present invention will be explained in more detail. The wet developer of the present invention has a resin, dye or pigment, charge control agent, etc. dispersed in a low dielectric constant and highly electrically insulating solvent, and the resin is insoluble or swellable in the solvent, or has only a small amount. Soluble. The methacrylic ester or acrylic ester component (hereinafter referred to as the first component) having an alkyl group having 4 or more carbon atoms is a component that is soluble in the solvent, and the styrene or styrene derivative component (hereinafter referred to as the second component) is a component that is soluble in the solvent. components) are insoluble. This 2
By forming a dispersion of the component copolymer resin in the solvent together with a pigment or dye and a charge control agent, a wet developer with relatively stable dispersion can be produced within a certain comparative range.

However, it has been found that toner images obtained from wet developers using such two-component resins sometimes have very weak resistivity to alkaline aqueous etching solutions. That is, when the obtained toner image is used as a resist layer and the non-image area is etched away with the etching solution, the toner image does not function as a resist layer,
Even toner images are etched away. As a result of intensive experiments, it was found that this behavior occurs when a copolymer resin containing a small proportion of the second component is used. Of course, the dependence on the amount of the second component changes depending on the number of carbon atoms in the alkyl group of the first component, but
It has been discovered that the more the component is, the better the resist properties are.

However, if the second component is used in too large a quantity, the dispersion stability will be poor and it will not be possible to withstand long-term use or storage.

In order to further improve dispersion stability without impairing resist properties, a methacrylic ester or acrylic ester having an alkyl group having 3 or less carbon atoms and a vinyl monomer having an acidic group are added to the third and fourth esters. We have discovered that this is possible by copolymerizing them as components.

When the number of carbon atoms in the alkyl groups of the first component and the third component are very similar, for example, when the first component is a butyl ester with 4 carbon atoms and the third component is a propyl ester with 3 carbon atoms, The effects of the present invention can be more effectively achieved by using an acrylic ester, ie, butyl acrylate, for the butyl ester, and a methacrylic ester, ie, propyl methacrylate, for the propyl ester.

From the above explanation and the examples described below, it is clear that by using the resin of this structure, a wet developer for printing plates that has strong resistivity against alkaline aqueous etching solutions and exhibits excellent fractional stability can be obtained. will become clear.

Examples of the ester residue of the acrylic ester or methacrylic ester having an alkyl group having 4 or more carbon atoms, which is the first component of the resin for a wet developer of the present invention, include n-butyl, glazed butyl, t -butyl, n-amyl,
Pentyl, hethymyl, -3-methylbutyl, 2-methylpentyl, 2-ethylbutyl, seC amyl, t-amyl, heptyl, oftyl, 2-ethylhexyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, and the like. It may also be substituted with a halogen atom such as 1,1,5-t, lJ hydroperfluoropentyl. Styrene and styrene derivatives, which are the second component, include alkylstyrenes such as methylstyrene, ethylstyrene, and isopropylstyrene, nohalokenated styrenes such as chlorostyrene, bromustyrene, and fluorostyrene, methoxystyrene, ethoxystyrene, and butoxystyrene. alkoxystyrenes such as p-hydroxystyrene, hydroxystyrenes such as 3-methoxy-4-hydroxystyrene, carboxystyrenes such as vinylbenzoic acid and methyl vinylbenzoate, and nitrostyrenes such as nitrostyrene and trinitrostyrene. Styrene derivatives containing sulfur such as styrenes, aminostyrenes such as m-aminostyrene and dimethylaminostyrene, ethyl p-vinylbenzenesulfonate, and α-position,
Substituents at the β position are listed, and these are described in Shunsuke Murahashi et al., "Synthetic Polymers IIJ (published by Asakura Shoten). Part 3.
Examples of the ester residue of the acrylic ester or methacrylic ester having an alkyl group having 3 or less carbon atoms, which is a component of , include methyl, ethyl, n-propyl, iso-propyl, and the like. Also 1,1.
3) It may be substituted with a hydrogen atom such as lihydroperfluoroprobyl.

Examples of the monomer having an acidic group as the fourth component include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, itaconic anhydride, maleic acid, maleic anhydride, maleic acid hafesters, fumaric acid, vinyl sulfoleic acid,
Examples include acrylamide propane sulfonic acid.

Furthermore, acrylamides, methacrylamides, vinyl monomers having a hydroxyl group, vinyl monomers having an epoxy group, vinyl acetate, monomers having carbon such as chlorine or fluorine, etc. can also be used.

From the viewpoint of resist properties and dispersion stability, the first component is 5 to 60% by weight, although it varies depending on the type and degree of monomer.
, the second component is 30-90% by weight, especially 40-80% by weight.
Preferably, the third component is copolymerized in a proportion of 5 to 40% by weight, and the fourth component is copolymerized in a proportion of 1 to 15% by weight.

The solvent of the wet developer used in the present invention is an organic solvent with a low dielectric constant and high electrical insulation, such as normal paraffin hydrocarbons, isoparaffin hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, Examples include halogenated aliphatic hydrocarbons, and isoparaffinic hydrocarbons are preferred, such as Shell Silua 1 (Shell Oil Co., Ltd.), Isopar G and Isopar H and Isopar K and Isopar L (Esso Oil Co., Ltd.), Ivy Solvent (Idemitsu Oil Co., Ltd.) (manufactured by) etc. can be used.

The charge control agent used in the wet developer of the present invention includes:
Examples include copper oleate, cobalt naphthenate, zinc naphthenate, manganese naphthenate, cobalt octylate, lecithin, sodium dioctyl sulfosuccinate, aluminum salt of steverytrozin, and the like.

As the dye or pigment used for the purpose of coloring the wet type developer for the present invention, any dye or pigment that is generally known as a colorant for wet type developers can be used. For example, oil black
Oil-soluble azo dyes such as Oillet, basic azo dyes such as Bismarck Brown and Chrysoidine, wool black,
Acidic azo dyes such as Amide Blank Green and Blue Black HF, direct dyes such as Direct Tape Lac E1 Congo Red, anthraquinone dyes such as Suetan (Iolet and Acid Blue), carbonium dyes such as Auramine, Malachite Green, and Crystal Violet, Rhodamine B Like rhodamine dye, safranin,
Examples include dyes such as quinone imine dyes such as nigrosine and methylene blue. As a pigment, carbon black,
Examples include phthalocyanine blue, phthalocyanine green, washing red, and benzidine yellow.

It is also possible to use surface-treated pigments such as carbon black dyed with nigrosine, kraft carbon, silicon oxide fine powder dyed with rhodamine B, microlis sprue, and the like. The amount of these added should be as small as possible, and preferably 50% by weight or less based on the resin. If the amount added is too large, dispersion stability tends to deteriorate and resist properties also tend to deteriorate.

In the wet type developer of the present invention, by selecting a charge control agent, dye, pigment, etc., it is possible to freely produce a toner having a positive charge or a toner having a negative charge.

In producing a wet type developer, it is a particularly preferred method to mix a soluble resin component into the solvent of the wet type developer for the purpose of producing the developer more stably and with good reproducibility.

Preferably, a resin having a basic group and soluble in the solvent, such as stearyl methacrylate-diethylaminopropyl methacrylate copolymer, lauryl acrylate vinylpyridine copolymer, lauryl acrylate-vinylimidazole copolymer, 2-ethylhexyl It is preferable to add an acrylate-dimethylaminoethyl acrylate copolymer or the like.

In order to improve fixing properties, a resin having a low softening point may be mixed with the resin of the present invention.

Examples include petroleum-based resins such as polybutadiene, polyisoprene, polyisobutylene, and polyethylene, and copolymers of these with styrene, acrylonitrile, etc., that is, resins generally referred to as rubber.

There are various known methods for producing wet developers. For example, a colorant and a resin are mixed and mixed in a solvent such as a petroleum-based aliphatic hydrocarbon, a small amount of aromatic hydrocarbon, or a halogenated aliphatic hydrocarbon. There is a method of dispersing the concentrated toner using a dispersing machine such as an attritor, ball mill, or kedimir, and diluting the obtained concentrated toner in a low dielectric constant, high electrically insulating solvent. A wet developer can be obtained by adding a coloring agent or a charge control agent to a low dielectric constant, highly electrically insulating solvent and polymerizing monomers in the solvent. There are ways to obtain it.

Of course, the present invention is not limited to the method for producing a wet developer.

Examples of comparative resins. Figures in parentheses are weight %.

Comparison■ Stearyl methacrylate/styrene (80
/20) Comparative) lauryl methacrylate/methyl methacrylate (5015
0) Comparison C) Styrene/butyl acrylate (9
515) Comparison (2) Stearyl methacrylate/vinyltoluene/ethyl methacrylate) (30/2
0150) Comparison (6) Butyl acrylate/α-methylstyrene/acrylic acid (70/20
/10) Resin example. Figures in parentheses are weight %.

(1) Lauryl methacrylate/styrene/ethyl methacrylate/acrylic acid (20/
60/1515 ) (2) Lauryl methacrylate/vinyl toluene/methyl methacrylate/crotonic acid (25/45/2515) (3) stearyl acrylate/α-methylstyrene/methyl methacrylate/itaconic acid (40/40/1515 )(
4) Stearyl methacrylate/styrene/methyl acrylate/methacrylic acid (12/80
15/3) (5) Butyl acrylate/styrene/propyl methacrylate/acrylic acid
(25155/1515) (6) Butyl methacrylate/styrene/methyl methacrylate/methacrylic acid (25150/15/10) These resins can be used in bulk polymerization, solution polymerization, suspension polymerization using peroxides and azo compounds as polymerization initiators. It can be synthesized extremely easily by turbidity polymerization, etc., and the synthesis method is generally well known. Molecular weight is 5,000 to 1
Although it can be used in the range of 1,000,000,000, low molecular weight resins have poor resistivity to etching solutions, and too large molecular weights are unfavorable in the production of wet developers. Therefore, a molecular weight of about 10,000 to 300,000 is the most preferable range, and methods for adjusting the degree of polymerization, such as adjusting the initiator concentration, polymerization degree regulator, polymerization temperature, and monomer concentration, are extremely well known. I was able to keep it within that range by using the following methods. - The molecular weight of the resin example measured by GPC was about 100,000.

The binder forming the photosensitive layer containing the organic photoconductive compound in the printing original plate developed with the wet developer of the present invention must be soluble in the alkaline aqueous etching solution.

Further, it is desirable that a toner image is formed using a wet developer and exhibits good adhesion to the toner image after fixing. Examples of binders for such a photosensitive layer include styrene maleic anhydride copolymer, styrene maleic anhydride Hafestel copolymer, maleic acid resin which is a reaction product of rosin and maleic anhydride, vinyl acetate-crotonic acid copolymer, Phenol resin, vinyl acetate-maleic anhydride copolymer, acid value approximately 5
Acrylic acid ester resins, methacrylic acid ester resins, etc., which exhibit 0 or more, can be mentioned.

As the organic photoconductive compound used in the printing plate of the present invention,
Examples include the following compounds.

(a) Aromatic tertiary amine compounds nitriphenylamine, diphenylbenzylamine, diβ-naphthyl)
Benzylamine, diphenylcyclohexylamine, etc. (b) Aromatic tertiary diamino compound: N, N', I
'F.

-Tetrabenzyl-P-diamine, N, N,
y, v'-tetrabenzylbenzidine, 1,1'-bis-(4-N,N-dibenzylaminophenyl)-ethane, 2,2-bis-(4-N,N,-dibenzylaminophenyl) -butane, bis-(4-N, N-di(p)
-chlorobenzylaminophenyl))=methane, 3,3
-cyphenylallyridine-4,4'-bis(N,N-diethyl-m-)luidine), 4,4'-bis(di-p-
tolylamino)-human, 1,1-triphenyl ethane,
etc. (c) Aromatic tertiary triamino compound: 4,4S4
τ-Tris(diethylaminophenyl)methane, 4-dimethylamino, 4', Eibis (jethi", 7mi4)
2.2') Methyl-triphenylmethane, etc. (d) Condensation main product: condensation main product of aldehyde and aromatic amine, reaction product of tertiary aromatic amine and aromatic halide, poly-roof 22 Shin-1,3,4-oxadiazole, reaction products of formaldehyde and fused polycyclic compounds, etc. (e) Metal-containing compounds = 2-mercaptobenzothiazole zinc salt, 2-mercaptopene, dioxazole lead salt, 2-mercapto-6-medoxybenzimidal-lead salt, S-hydroxy-quinoline-aluminum salt, 2-hydroxy-4-methyl-azobenzene-copper salt (
f) Polyvinylcarbazole compounds: polyvinylcarbazole, halogen-substituted polyvinylcarbazole, copolymers of vinylcarbazole and styrene, copolymers of vinylanthracene-vinylcarbazole, etc.

@ Heterocyclic compound: 1,3.5-)liphenylvirazoline, 1-phenyl-3-(P-dimethylaminostyryl)-5-(P-dimethylaminophenyl)-pyrazoline, 1,5-diphenyl- 3-styryl: pyrazoline,
1.3-diphenyl-5-styryl-hylasoline, 1,
3-diphenyl-5-(P-dimethylaminophenyl)
-pyrazoline, 3-(4'-di)l-aminophenyl)-5,6-di(4'-methoxyphenyl)-1,2
, 4-triazine, 3-(4'-dimethylaminophenyl)-5,6-dipyridyl-1.2.4-)riazine,
2-phenyl-4-(4'-dimethylaminophenyl)
-quinazoline, 6-hydroxy-2,3-di(p-methoxyphenyl)-benzofuran, 2,5-bis-[4-
ethylamino-phenyl-(17)=1.3.4-oxadiazole, etc.

The organic photoconductive compounds used in the present invention include phthalocyanine pigments, quinacridone pigments, indigo pigments, cyanine pigments, perylene pigments, bisbenzimidazole pigments,
Good printing plates can also be obtained using pigments such as quinone pigments, azo pigments, and indigo pigments. As the base for the printing plate of the present invention, all conventionally known bases for printing plates can be used. For example, metal plates such as aluminum plates, zinc plates, magnesium plates, copper plates, etc. Films and synthetic papers made of polyester, cellulose acetate, polystyrene, polycarbonate, polyamide, polypropylene, etc. Examples include processed paper such as resin-coated paper, but since the photoconductive compound and binder are removed by etching treatment after image formation, and the non-image area must have hydrophilic properties, the hydrophobic surface It is necessary to make the base hydrophilic in advance. A metal plate, especially an aluminum plate, is most suitable, but surface treatments such as grain treatment, alkali treatment, acid treatment, and anodization are preferred. In addition, films may be coated with a relatively highly hydrophilic polymer compound and crosslinked, or a certain type of metal may be vapor-deposited or laminated. When using an insulating paste, it is desirable to conductive treatment on the surface of the paste.

To produce a printing original plate, the conductive conductive compound and the binder of the present invention are dissolved in a solvent, and if the photoconductive compound is not dissolved, a dispersion is prepared using a colloid mill, homogenizer, supercurrent dispersion machine, etc. ), and a sensitizing dye is added thereto, coated on the support to a thickness of 1 to 30 μm, and dried.

Those that can be used as solvents include all organic solvents that are capable of dissolving the binder and dissolving or dispersing the photoconductive compound.

For example, alcohols such as methanol, ethanol, propatool, butanol, hexyl alcohol, cellosolves such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, aromatics such as benzene, toluene, xylene, cyclic ethers such as dioxene, tetrahydrofuran, acetic acid. Examples include esters such as ethyl, butyl acetate, and aluminum acetate, ketones such as acetone, methyl isobutyl ketone, and methyl ethyl ketone, dimethylforamide, dimethyl sulfoxide, and halogenated hydrocarbons, but they are not suitable for solubility, cost, safety, etc. A mixture of two or more solvents is often used.

The printing plate of the present invention is obtained by forming a toner image on a printing original plate by electrophotography and then etching the non-image area with an alkaline aqueous etching liquid. Examples of the alkali include sodium hydroxide, potassium hydroxide, rum, sodium carbonate, sodium silicate, sodium chloride, potassium phosphate, and ammonia. Further, it is more preferable to add alcohol to the present alkaline aqueous etching solution in terms of etching speed.

Alcohols include lower alcohols such as methanol, ethanol, glopagul, be/zyl alcohol, phenethyl alcohol, aromatic alcohols, and hietile 7f.
I) Cole, diethylene glycol, triethylene glycol, polyethylene glycol, cellosolves can be used. Etching treatment can be performed using an alkaline aqueous solution alone, but it is preferable to use amino alcohols such as jetanolamine, triethanolamine, etc. from the etching speed, safety and hygiene aspects, and from the viewpoint of resolution and image reproducibility, it is preferable to use amino alcohols. An alkaline alcohol aqueous solution containing a combination of alcohol and alcohol is most suitable.

When this etching treatment is followed by washing with water and treatment with a diluted acid aqueous solution/liquid, it exhibits excellent properties in terms of scumming and image reproducibility during printing.

, Etching treatment liquid example (1) EDTA-4H3,9 Benzyl alcohol 1! ! 'Monoethanolamine 5I triethanolamine
50g NaOH151 Sodium sulfite and formalin reaction product 2g Adjust the total amount to IL with water (2) Sodium metaphosphate 311
Phenethyl alcohol 30.9 Monoethanolamine 50J' Sulfite vinegar soda and formalin reaction product 2I! Adjust the total volume to 16 with water.

Example 1 Creation of printing original plate (a) Ethyl methacrylate-butyl methacrylate-acrylic acid copolymer (composition ratio 50/3) as binder
0/20 weight ratio) was dissolved in a mixed solvent of 100 g of butyl acetate and 20S of butanol, and in this solution, 8 g of 1.3.5-) liphenylvirazoline was dissolved as an organic photoconductive compound. Rhodamine B as a sensitive pigment
5 cc of a 1% DMF solution was added, and the total amount was adjusted to 150 g with butyl acetate.

Coat with a wire bar to a grained and anodized 250μ aluminum plate with a solid content of 5μ,
Dry printing plate [I got a vision.

(b) 10, I of the octylharfester form of styrene maleic anhydride (acid value 165) as a binder
was dissolved in 80 g of xylene and a mixed solvent of butanol 20I and tetrahydrofuran 20II, and 2,5-bis(4'-diethylaminophenyl)-1,3°4-oxadiazole 8II was dissolved as an organic photoconductive compound. Add 5 cc of a 1% methanol solution of ethyl violet as a sensitizing dye and dilute the total volume with xylene for 15 cc.
Adjusted to 0I. Hereinafter, a printing original plate CB) was obtained by the method (a) above.

(C) m-cresol formaldehyde resin 109 as a binder, L-type steel phthalocyanine 29 as an organic photoconductive compound, and xylene 40I! , butanol (140.9 g) was added and dispersed in a ball mill for 3 hours to obtain a printing original plate [C] according to the method of Example (a).

Example 2 Production of wet developer (a) Copolymer 4I of wet developer resin example (1) and carbon black surface treated with colorant [Nigrosine/MA-100 (manufactured by Mitsubishi Kasei Corporation) = ShiI] 0.419 and toluene 25I and Isopar GIO9 and the charge control agent cobal naphthenate) 0061 in an attritor.
A concentrated toner was obtained by time dispersion. - After gradually dropping the concentrated toner into Isopar Glt, the total amount was adjusted to 1.5 t with Isopar G to obtain a wet developer (4).

(b) The following wet type developer was obtained in exactly the same manner except that the resin and colorant were changed.

Wet developer number Colorant Resin (6)
Same as developer ■ (2) (C)
(3)(t)) (
4) @(5) ■ (6) G) Comparison ■0
Comparative small) (I)
Comparison (Oa> - comparison 0) (6) I comparison ■υ
Oil black FS (1)
(2) (to)
An example of mixing two types of resins to further improve dispersion stability or fixing power is shown below.

The manufacturing method was the same as (&) in Example (2), and the amount of resin mixed was 3II. Moreover, oil black FS was used as a coloring agent.

(f) Resin (1) and lauryl methacrylate-dimethylaminoethyl methacrylate (90/10) ψ) Resin (3) and Q Resin (5) and Example 3 (a) Example 1 (a) to (e The printing original plate obtained in ) was negatively charged by applying a corona discharge of 16 kV in a dark place, and then a positive image was exposed to white light.

Immediately, development was performed using the wet developer obtained in Examples 2(a) to (c), and heat fixing was performed using fusB. Next, these were immersed in the above etching solution for about 30 seconds to remove the non-image area other than the toner image to obtain a printing plate.

Here, the resistivity of the toner image area was evaluated by measuring the resolution.

佽) The amount of toner (-~(@) in Example 2 was increased to 3L, and the plate making machine ICP- for Mitsubishi Diafax Master was manufactured.
11 (manufactured by Mitsubishi Paper Industries) was used to investigate the dispersion stability of the toner. That is, only the developing section of V-11 was driven to circulate the toner at high speed for about 1 hour, and the state of aggregation of toner particles was examined. Further, the toner was stored for one month and the state of dispersion over time was examined.

From the above results, when using the comparative resin, the etching solution! It can be seen that the resolution is inferior due to the weak resistivity.

There are some good ones, but their dispersibility is poor and they cannot be put to practical use.

In addition to the resin of the present invention, there are also wet-type developers with good dispersibility, but they have poor resistivity and are unsuitable for use in the printing plate of the present invention.

Procedural amendment (spontaneous) Tsunozuki 24, 1980 1, Indication of case 1981 Patent Application No. 10325 2,
Name of the invention: Wet developer for printing plates 3. Relationship with the person making the amendment: Patent applicant: 4. Agent address: 5, Mitsubishi Paper Mills Co., Ltd., 3-4-2 Marunouchi, Chiyoda-ku, Tokyo 100. Order for amendment. Date 8, Contents of amendment (1) "Star Tan Violet" on page 13, line 14 of the specification was corrected to "r star tan violet"; 2) "Craft carbon" on page 14, line 5 of the specification was changed to "graft carbon". (3) Corrected “polyisobutylene” on page 15, line 11 to “polyinbutylene 1” Corrected “dioxane” on page 23, lines 17 to 18 to “dioxane” (5) Page 23, line 19, "aluminum acetate" is corrected to "r amyl acetate" 7 Page 25, line #, "forman reactant" is corrected to "formalin reactant"

Claims (1)

[Claims] (1) A toner image is formed on a printing original plate having a layer containing an organic photoconductive compound on a conductive substrate using a wet developer using an electrophotographic method, and after fixing, the areas other than the toner image area are etched with an alkaline etching solution. In a wet developer for a printing plate obtained by etching away the non-image area of Acrylic ester, (b) 30-90% by weight of styrene or styrene derivative, (c) 5-40% by weight of acrylic ester or methacrylic ester having an alkyl group having 3 or less carbon atoms, (d) 1 The above-mentioned wet developer for printing plates, which is a copolymer containing ~15% by weight of a monomer having an acidic group.