JPH096059A - Electrophotographic planographic printing plate - Google Patents

Abstract

PURPOSE: To obtain a planographic printing plate having stability and excellent in image characteristics because the electrically conductive layers have no humidity dependency and are excellent in controllability and stability of electric conductivity. CONSTITUTION: This planographic printing plate has an electrically conductive middle layer disposed on one side of the substrate, a photoconductive layer disposed on the middle layer and an electrically conductive back coating layer disposed on the other side of the substrate. At least one of the middle layer and the back coating layer is formed with an electrically conductive compsn. contg. sulfonated polyaniline in which the amt. of sulfonic acid groups bonding to arom. rings is >=10mol% of the amt. of the arom. rings. The surface resistance of the middle layer is preferably 1×10<2> -1×10<8> Ωsq. and that of the back coating layer is preferably 1×10<2> -1×10<12> Ω/sq.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet electrophotographic lithographic printing plate, and more specifically, it has excellent image characteristics because the conductive layer does not depend on humidity and has excellent conductivity control and stability. The present invention relates to a lithographic printing plate which is obtained by electrophotography.

[0002]

2. Description of the Related Art Conventionally, as a lithographic printing method, a toner image is formed on the surface of a printing original plate by an electrophotographic method, and after fixing, a non-image portion is subjected to an etching treatment to form a printing plate, which is applied to a lithographic printing machine. Printing methods are widely used. In general, this electrophotographic lithographic printing plate uses a paper or a plastic film as a support, and provides a photoconductive layer on one side of the support directly or through a conductive intermediate layer, and a conductive back surface on the other side of the support. It is manufactured by providing a coat layer. Here, as the conductive coating layer, a cation-based or anion-based polymer conductive agent, an inorganic conductive agent such as carbon, metal, or metal oxide is known.

However, when a polymer conductive agent is used as the conductive coating layer, the conductivity changes depending on the humidity, and when an inorganic conductive agent is used, the conductivity does not change depending on the humidity, but Since control is difficult, there has been a problem that stable image characteristics cannot be obtained.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide stable and image characteristics by controlling the humidity of the conductive layer and by controlling the conductivity and stability. It is to provide an excellent electrophotographic lithographic printing plate.

[0005]

The electrophotographic lithographic printing plate of the present invention comprises a conductive intermediate layer provided on one side of a support, and a photoconductive substance powder provided on the conductive intermediate layer. ,
In a electrophotographic lithographic printing plate comprising a photoconductive layer composed of a sensitizer and a binder resin, and a conductive backcoat layer provided on the other surface of the support, the conductive intermediate layer and the conductive intermediate layer At least one of the conductive back coat layers is a conductive composition containing a sulfonated polyaniline in which the amount of sulfonic acid groups bonded to an aromatic ring is 10 mol% or more based on the aromatic ring. is there.

The present invention will be described in detail below.

The support in the lithographic printing plate of the present invention means
Paper or plastic film, which may be paper impregnated or coated with plastic. The plastic film may be made of a single polymer such as polyester, nylon, polypropylene or polyethylene, or a mixture thereof, or a laminated structure. In particular, plastic films containing cavities
It is suitable in terms of water resistance, dimensional stability, handleability, and the like.

The conductive composition used for the conductive intermediate layer or conductive back coat layer in the lithographic printing plate of the present invention is
Sulfonated polyaniline having an amount of sulfonic acid groups bonded to an aromatic ring of 10 mol% or more with respect to the aromatic ring, a solvent, amines and / or quaternary ammonium salts, and a sulfonic acid group and / or a binder. A conductive composition comprising a water-soluble or water-dispersible copolyester having the alkali metal salt bonded thereto or a hydrophilic polymer such as polyvinyl alcohol is preferable.

Here, as the sulfonated polyaniline,
Aniline, an aniline-based copolymer sulfonate obtained by copolymerizing at least one compound selected from the group consisting of aniline derivatives and phenylenediamines with an aminobenzenesulfonic acid compound, and sulfonation, and An aniline-based copolymer sulfone obtained by copolymerizing at least one compound selected from the group consisting of aniline, aniline derivatives and phenylenediamines with an alkoxy group-substituted aminobenzene sulfonic acid compound, and then performing sulfonation. Compounds are preferred in the present invention.

Further, the coating property of the conductive composition of the present invention,
From the viewpoint of improving the spreadability and the hardness of the coated body, it is more preferable to use the copolymerized polyester containing 1 to 20 mol% of 5-sulfoisophthalic acid unit in combination.

Here, the aniline derivative is a compound obtained by substituting the amino group of aniline or hydrogen of the benzene ring with an alkyl group, an alkoxy group, an aryl group, a sulfonic acid group or the like. Examples thereof include N-methylaniline and N-
Ethylaniline, N-n-propylaniline, N-is
o-propylaniline, Nn-butylaniline, N-
Examples thereof include N-alkylanilines such as tert-butylaniline and aminoanisole.

The phenylenediamines include phenylenediamine, N-phenylphenylenediamine,
Examples thereof include N, N'-diphenylphenylenediamine and N-aminophenyl-N'-phenylenediamine.

As the alkoxy group-substituted aminobenzene sulfonic acids, when the alkoxy group is a methoxy group, aminoanisole sulfonic acids are exemplified.
Aminoanisole-3-sulfonic acid, 2-aminoanisole-4-sulfonic acid, 2-aminoanisole-5-sulfonic acid, 2-aminoanisole-6-sulfonic acid, 3
-Aminoanisole-2-sulfonic acid, 3-aminoanisole-4-sulfonic acid, 3-aminoanisole-5-
Sulfonic acid, 3-aminoanisole-6-sulfonic acid,
4-aminoanisole-2-sulfonic acid, 4-aminoanisole-3-sulfonic acid and the like can be mentioned. Similarly, it is also possible to use a compound in which the alkoxy group is an ethoxy group, an iso-propoxy group or the like. However, in the present invention, 2-aminoanisole-3-sulfonic acid, 2-aminoanisole-4-sulfonic acid, 2-aminoanisole-5-sulfonic acid, 2-aminoanisole-6-sulfonic acid, 3-amino Anisole-2-sulfonic acid, 3-aminoanisole-4-sulfonic acid and 3-aminoanisole-6-sulfonic acid are preferably used.

The sulfonated polyaniline copolymer in the present invention is a copolymer of at least one compound selected from the group consisting of aniline, the aniline derivative and the phenylenediamines and the (alkoxy group-substituted) aminobenzenesulfonic acid. The combined product can be obtained by sulfonation with a sulfonating agent such as concentrated sulfuric acid.

As described above, the sulfonated polyaniline copolymer used in the present invention has a sulfonic acid group of 10 mol% or more based on the aromatic ring, preferably 20%.
It is a mol% or more, more preferably 40 mol% or more. Even if aromatic rings containing sulfonic acid groups and aromatic rings not containing sulfonic acid groups are mixed or arranged alternately, there is no problem for the purpose of the present invention. When the sulfonic acid group content of the sulfonated polyaniline copolymer is less than 10%, the water of the copolymer,
The solubility or dispersibility in alcohol or a mixed solvent system thereof becomes insufficient, resulting in poor coatability and spreadability on a support, and the conductivity of the obtained coating film tends to remarkably decrease. . The number average molecular weight of the sulfonated polyaniline copolymer used in the present invention is 300 to 500.
It is 000, and 1000 or more is preferable in terms of solubility in the solvent and strength of the coating film.

The proportion of the sulfonated polyaniline copolymer used is 0.1 to 20 parts by weight, preferably 0.5 to 5 parts by weight, based on 100 parts by weight of the solvent. When the proportion of the sulfonated polyaniline copolymer used is less than 0.1 parts by weight, the long-term storage stability of the solution is deteriorated, pinholes are easily generated in the coating layer on the surface, and the conductivity of the coated surface is significantly deteriorated. On the other hand, if the proportion used exceeds 20 parts by weight, the solubility and dispersibility of the copolymer in water or a water / organic solvent system and the flatness of the coating layer tend to deteriorate, which is not preferable.

As the solvent, any organic solvent can be used as long as it does not dissolve or swell a support such as a polyester film, but it is preferable to use a mixed solvent with water or an organic solvent such as water / alcohol. Not only is it environmentally preferable, but there are cases where the coating property on the support and the conductivity are improved.

The organic solvent includes alcohols such as methanol, ethanol, propanol and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone, cellosolves such as methyl cellosolve and ethyl cellosolve, methyl propylene glycol and ethyl propylene glycol. Propylene glycols, amides such as dimethylformamide and dimethylacetamide, and pyrrolidones such as N-methylpyrrolidone and N-ethylpyrrolidone are preferably used. These are used by mixing with water at an arbitrary ratio.
Specific examples thereof include water / methanol, water / ethanol, water / propanol, water / isopropanol, water / methyl propylene glycol, and water-ethyl propylene glycol. The ratio used is preferably water / organic solvent = 1/10 to 10/1.

Further, amines and / or quaternary ammonium salts, which are constituent components of the conductive composition used in the present invention, will be described. As the amine, a compound represented by the following general formula (1) is used.

Embedded image In the formula, R ₁ , R ₂ and R ₃ are each independently of the other,
Hydrogen, alkyl having 1 to 4 carbon atoms (C _{1 to} C ₄ ), CH ₂
OH, CH ₂ CH ₂ OH, CONH ₂ or NH ₂ . The quaternary ammonium salt has the following general formula
The compound represented by (2) is used.

Embedded image In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently of each other hydrogen, alkyl having 1 to 4 carbon atoms (C _{1 to} C ₄ ),
CH ₂ CH ₂ OH, CONH ₂ or NH ₂ . In addition, X is an anion of an acid, and Cl ⁻ , Br ⁻ ,
I ^-, indicating the sulfate, the nitrate or phosphate radical.

In the present invention, the conductive composition can form a coat layer having good coatability, ductility, and surface strength with only the above components, but it does not contain a polymer compound and / or a surfactant soluble in a solvent. Further, when used in combination, it is possible to coat a support having poor wettability.

Examples of polymer compounds suitable as binders for this purpose include water-soluble resins such as polyacrylamide and polyvinylpyrrolidone, water-soluble or water-dispersible copolyesters containing a hydroxyl group or a carboxylic acid group, and polyacrylics. Acid, acrylic resin such as polymethacrylic acid, acrylic ester resin such as polyacrylic acid ester and polymethacrylic acid ester, ester resin such as polyethylene terephthalate and polybutylene terephthalate, polystyrene, poly-α-methylstyrene, polychloromethyl Styrene resin such as styrene, polystyrene sulfonic acid, polyvinyl phenol, vinyl ether resin such as polyvinyl methyl ether, polyvinyl ethyl ether, polyvinyl alcohol, polyvinyl formal, poly Polyvinyl alcohols such as butyral, a novolak, a phenol resin such as a resol is used. Among them, from the viewpoint of compatibility with the sulfonic acid group-containing polyaniline of the present invention and from the viewpoint of adhesiveness with a support such as polyester, a water-soluble or water-dispersible copolymerized polyester containing a hydroxyl group or a carboxylic acid group is used. preferable.

In the present invention, for the purpose of improving the wettability to the conductive composition, surfactants such as anionic surfactants such as alkylsulfonic acid, alkylbenzenesulfonic acid and alkylcarboxylic acid, alkylamine and alkyl 4 are used. Cationic surfactants such as primary amines, amphoteric surfactants such as carboxybendine and aminocarboxylic acids, nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene sorbitan fatty acid esters, and fluoroalkylcarboxylic acids, Fluorine-based surfactants such as fluoroalkylcarboxylic acid, perfluoroalkylbenzenesulfonic acid, perfluoroalkyl quaternary ammonium and perfluoroalkyl polyoxyethylene ethanol are used. From the viewpoint of improving the wettability to the polyester support, a fluorosurfactant is preferable.

The total amount of the polymer compound and the surfactant is 0 to 200 parts by weight, preferably 0 to 50 parts by weight, based on 100 parts by weight of the solvent. When the ratio of the total amount of the polymer compound and the surfactant exceeds 200 parts by weight, the coating property is improved but the flatness is lowered, or the flatness is improved but the conductivity is deteriorated.

The conductive intermediate layer or the conductive back coat layer is applied by a gravure roll coating method,
There are a reverse roll coating method, a knife coater method, a dip coating method, a spin coating method, and the like, but the coating method suitable for the conductive composition is not particularly limited. There are an in-line coating method in which the film is coated simultaneously in the film-forming step and an offline coating method in which the film-forming roll is independently manufactured after the film-forming roll is manufactured. . Although the sulfonated polyaniline of the present invention is unstable at a high temperature of 250 ° C. or higher, it has good thermal stability even at 200 ° C. for about 3 minutes, so it depends on the kind of the polymer compound and the additive depending on 20 for a short time
Heating at 0 ° C does not adversely affect the conductivity. Rather, from the viewpoint of improving the conductivity of the coated surface, it is preferable to heat at around 200 ° C. for 30 seconds or less.

In the present invention, when a conductive layer other than sulfonated polyaniline is provided on either the conductive intermediate layer or the conductive back coat layer, the conductive layer may be a metal, a metal oxide, particularly zinc, magnesium, Oxides of metals selected from tin, potassium, barium, indium, molybdenum, aluminum, titanium, silicon, etc., preferably fine particles of crystalline oxides or composite oxides thereof, or carbon black as a polymer binder, for example, cellulose resin. , Mixed with acetal-based resin, urethane-based resin, acrylic-based resin, etc., dispersed or dissolved in organic solvent or water-based solvent, or ion-conducting surfactant or polymer such as cation-based or anion-based support It may be applied to the body or laminated by another method. However, it is more preferable to use sulfonated polyaniline for both the conductive layers.

The conductive intermediate layer of the present invention has a surface resistance value of 1
It is preferably × 10 ² to 1 × 10 ⁸ Ω / □, and 1
It is more preferable that it is × 10 ⁴ to 1 × 10 ⁷ Ω / □. If the surface resistance value exceeds 1 × 10 ⁸ Ω / □, the flow of charges is hindered and fogging is likely to occur. On the contrary, 1 × 10 ² Ω
If it is less than / □, pinholes are likely to occur.

The conductive back coat layer of the present invention is preferably made of the same material as the conductive intermediate layer and has a surface resistance value of 1 × 10 ² to 1 × 10 ¹² Ω / □. More preferably, it is 1 × 10 ⁵ to 1 × 10 ⁹ Ω / □. When the surface resistance value is 1 × 10 ¹² Ω / □ or more, the flow of charges is obstructed and pinholes are likely to occur.
On the contrary, when it is 1 × 10 ² Ω / □ or less, it is difficult to obtain a clear image.

In the present invention, the photoconductive layer is a mixed solution prepared by dispersing a photoconductive powder such as zinc oxide or titanium oxide and an insulating synthetic resin binder in an organic solvent, and further adding a sensitizer. Can be formed by coating and drying on the conductive intermediate layer.

The method of laminating the photoconductive layer on the intermediate layer is not particularly limited, but a coating method of applying the above-mentioned mixed liquid on the surface of the intermediate layer is particularly suitable. That is, it is preferable to apply a dry heat treatment after coating the intermediate layer surface. As the coating method, roll coating method such as gravure and reverse, doctor knife method and air knife,
A usual method such as a nozzle coating method can be used. Further, a method of applying by a spray method may be used.

Further, the photoconductive layer may be applied to the surface of the film after the production, or it is preferable to apply the photoconductive layer after the film production process, ie, the raw material for casting or uniaxial stretching, and then perform the stretching treatment.

The thickness of each layer laminated by such a method is not particularly limited, but is 7 as a support.
5 to 200 μm, 0.1 to 5 μm for the conductive intermediate layer
m, the conductive back coat layer is preferably 0.1 to 5 μm, and the photoconductive layer is preferably 5 to 20 μm.

In the present invention, the support is a void-containing polyester film obtained by at least uniaxially stretching an unstretched sheet of a mixture of polyester and a thermoplastic resin incompatible with the polyester. It is preferable. Examples of the thermoplastic resin which is incompatible with such polyester include polystyrene resin, polyolefin resin, polyacrylic resin,
Examples thereof include polycarbonate resin, polysulfone-based resin, and cellulose-based resin. Among these,
Polyolefin resins such as polystyrene resins, polymethylpentene and polypropylene are preferred. The blending amount of these thermoplastic resins varies depending on the amount of voids to be formed, but is generally preferably 3 to 35% by weight based on the entire mixture of polyester and thermoplastic resin.

[0033]

In the electrophotographic lithographic printing plate of the present invention, at least one of the conductive intermediate layer and the conductive backcoat layer has an amount of sulfonic acid groups bonded to the aromatic ring of 10 or more relative to the aromatic ring.
Since it is a conductive composition containing sulfonated polyaniline in an amount of at least mol%, it has almost no humidity dependency, that is, it is possible to obtain a printed image having a clear image even under low humidity or high humidity.

[0034]

EXAMPLES Examples and comparative examples of the present invention are shown below, but the present invention is not limited thereto. First, the evaluation method used in the present invention will be described.

1) Surface resistance value The measurement was carried out at 25 ° C. under three conditions of 15, 50 and 95% RH.

2) Vividness of printed matter At 25 ° C., under three conditions of 15, 50 and 95% RH,
The printing plate on which an image was formed after being left for 24 hours was printed on 10,000 sheets using a TEXEL AR010 type offset printing machine of Shinano Seiki Co., Ltd. and judged as follows: (in the case of monochrome printing): 150% 10% The halftone dots are completely reproduced on both the plate and the printed matter. B: Some of the above-mentioned halftone dots are missing. X: Many of the above-mentioned halftone dots are missing. (For 4-color color printing) O: No color misregistration. Δ: A slight color shift is recognized, but there is no particular problem in practical use. X: A considerable amount of color misregistration was observed and there was a practical problem.

Next, the preparation of the conductive composition coating liquid will be described.

(Synthesis Example 1) Preparation of Sulfonic Acid Group-Containing Polyester and Aqueous Dispersion Liquid First, a sulfonic acid group-containing polyester was synthesized by the following method and the dispersion liquid was prepared. Dimethyl terephthalate 49 mol%, dimethyl isophthalate 49 mol% and sodium 5-sulfoisophthalate 2 mol% are used as dicarboxylic acid components, and ethylene glycol 50 mol% and neopentyl glycol 50 mol% are used as glycol components. Transesterification reaction and polycondensation reaction were carried out by the method. The glass transition temperature of the obtained sulfonic acid group-containing polyester was 69 ° C. 300 parts by weight of this sulfonic acid group-containing polyester and 150 parts by weight of n-butyl cellosolve are heated and stirred to form a viscous solution, and 550 parts by weight of water is gradually added with stirring.
A uniform pale-white aqueous dispersion having a solid content of 30% by weight was obtained. This dispersion was further added to an equal volume mixture of water and isopropanol to prepare a sulfonic acid group-containing polyester aqueous dispersion having a solid content of 8% by weight.

(Synthesis Example 2) Preparation of Sulfonic Acid Group-Containing Polyaniline Coating Solution To a mixture of 10 parts by weight of phenylenediamine and 19 parts by weight of p-aminobenzenesulfonic acid, a hydrochloric acid solution of ammonium sulfate was added dropwise under acidic conditions of hydrochloric acid. After completion of the dropping, the reaction product was stirred for a predetermined time and then the reaction product was separated by filtration, washed and dried to obtain a powdery copolymer. This copolymer was added to concentrated sulfuric acid 1
000 parts by weight, and the mixture was stirred at a predetermined temperature for 6 hours for sulfonation. The reaction product was dropped into an ethanol solution, and the obtained precipitate was separated by filtration, washed and dried to obtain a sulfonated polyaniline. This compound has an IR spectrum of 11
Absorption of a sulfonic acid group was recognized near 00 cm ^-1 . At this time, the content of sulfone groups in the sulfonated polyaniline was 50 mol% with respect to the aromatic ring. 2.0 parts by weight of the sulfonated polyaniline was dissolved in 1.2 parts by weight of trimethylamine, 50 parts by weight of water and 50 parts by weight of isopropanol. A liquid prepared by mixing this liquid with 100 parts by weight of the dispersion liquid of Synthetic Agent 1 was used as a conductive composition coating liquid. This coating solution was dark green and no insoluble matter was observed in appearance.

[Example 1] As a support, a white polyester film containing a cavity having a thickness of 125 µm was used. On one side of this void-containing white polyester film support, the conductive composition coating liquid prepared in Synthesis Examples 1 and 2 was applied,
A 4 μm thick conductive intermediate layer was formed. Further, on this intermediate layer, photoconductive zinc oxide (# 400 manufactured by Sakai Chemical Co., Ltd.)
0), acrylic resin LR333 (Mitsubishi Rayon Co., Ltd.)
And Acrylic 44-179 (manufactured by Dainippon Ink and Chemicals, Inc.) at a weight ratio of 63/7/3, and 0.1 part by weight of rose bengal (sensitizer) and 90 parts of toluene.
What was added in an amount of 1 wt.
Further, the conductive composition coating liquid prepared in Synthesis Examples 1 and 2 was applied on the other surface of the support to form a conductive back coat layer having a thickness of 3 μm. Thus, an electrophotographic planographic printing plate was produced.

[Example 2] Electrophotographic lithographic printing was performed in the same manner as in Example 1 except that the conductive composition coating solution prepared in Synthesis Examples 1 and 2 was further dispersed in a ball mill for 1 hour. A plate was made.

Example 3 On the other surface of the support, potassium titanate whiskers (manufactured by Otsuka Chemical Co., Ltd., TISTA) were used.
T-PHS), copolyester resin (manufactured by Toyobo Co., Ltd .: MD16), water, and isopropyl alcohol mixed at a weight ratio of 30/30/33/8 are applied with a wire bar (# 10), An electrophotographic lithographic printing plate was produced in the same manner as in Example 1 except that the conductive backcoat layer having a solid content of 3 μm was formed by drying at 160 ° C. for 1 minute.

[Example 4] An electrophotographic method was carried out in the same manner as in Example 1 except that a carbon black-containing acrylic resin dispersed by a ball mill for 1 hour was applied on one surface of a support to form a conductive intermediate layer. A planographic printing plate was prepared.

[Comparative Example 1] A carbon black-containing acrylic resin dispersed by a ball mill for 1 hour was applied on one surface of a support to form a conductive intermediate layer, and potassium titanate was applied on the other surface of the support. Whiskers (Otsuka Chemical Co., Ltd.)
Manufactured by TISTAT-PHS), a copolyester resin (manufactured by Toyobo Co., Ltd .: MD16), water, and isopropyl alcohol are mixed at a weight ratio of 30/30/33/8,
Furthermore, except that the material was dispersed by a ball mill for 1 hour and applied with a wire bar (# 10) and dried at 160 ° C. for 1 minute to form a conductive back coat layer having a solid content thickness of 3 μm.
An electrophotographic lithographic printing plate was prepared in the same manner as in Example 1.

[Comparative Example 2] A carbon black-containing acrylic resin (not dispersed in a ball mill) was formed on one surface of a support.
To form a conductive intermediate layer, and then whiskers of potassium titanate (Otsuka Chemical Co., Ltd.) on the other surface of the support.
Co., Ltd., TISTAT-PHS), a copolyester resin (manufactured by Toyobo Co., Ltd .: MD16), water, and isopropyl alcohol mixed at a weight ratio of 30/30/33/8 and applied with a wire bar (# 10). And 1 at 160 ℃
An electrophotographic lithographic printing plate was prepared in the same manner as in Example 1, except that the conductive backcoat layer having a solid content of 3 μm was formed by drying for a minute.

[Comparative Example 3] An anionic polymer solution was applied on one side of a support to form a conductive intermediate layer, and potassium titanate whiskers (Otsuka Chemical Co., Ltd.) were formed on the other side of the support. Co., Ltd., TISTAT-PHS, copolyester resin (manufactured by Toyobo Co., Ltd .: MD16), water, isopropyl alcohol mixed at a weight ratio of 30/30/33/8 with a wire bar (# 10). ) And then
An electrophotographic lithographic printing plate was produced in the same manner as in Example 1 except that the conductive backcoat layer having a solid content of 3 μm was formed by drying at 160 ° C. for 1 minute.

[Comparative Example 4] An acrylic resin containing carbon black (not dispersed in a ball mill) was formed on one surface of a support.
In the same manner as in Example 1 except that a conductive intermediate layer was formed by coating with the above, and an anionic polymer liquid was applied on the other surface of the support to form a conductive back coat layer. A planographic printing plate was prepared.

Table 1 shows the evaluation results of the electrophotographic lithographic printing plate obtained as described above. As shown in Table 1, Examples 1 to 4
All electrophotographic lithographic printing plates of the present invention show a clear image regardless of humidity. On the other hand, Comparative Examples 1 and 2
However, the surface resistance value was different from that of the example, and a clear image could not be obtained. The surface resistance values of Comparative Examples 3 and 4 fluctuate due to humidity, a clear image cannot be obtained at 15, 95% RH in Comparative Example 3, and any of Comparative Example 4 A clear image could not be obtained even under the RH condition.

[0049]

As described above, in the electrophotographic lithographic printing plate of the present invention, at least one of the conductive intermediate layer and the conductive backcoat layer is formed of a conductive composition containing sulfonated polyaniline. Therefore, there is almost no humidity dependency of these conductive layers, and a printed matter having a clear image can be obtained under any humidity condition.

In particular, when the surface resistance values of both the conductive intermediate layer and the conductive back coat layer are within the preferred range of the present invention, a printed matter with a particularly clear image can be obtained, and the electrophotographic planographic printing plate can be obtained. Very useful as a printing plate.

The conductive composition containing sulfonated polyaniline used in the electrophotographic lithographic printing plate of the present invention has almost no change in surface resistance value due to dispersion conditions and the like,
It is easy to control conductivity. As described above, in the production of the electrophotographic lithographic printing plate of the present invention, a complicated dispersion step is not necessary and in-line coating is possible, which is effective in simplifying the production process and reducing the cost.

[0052]

[Table 1]

Claims (6)

[Claims] 1. A conductive intermediate layer provided on one surface of a support, and a photoconductive layer provided on the conductive intermediate layer and comprising a photoconductive substance powder, a sensitizer and a binder resin. , In an electrophotographic lithographic printing plate comprising a conductive backcoat layer provided on the other surface of the support, at least one of the conductive intermediate layer and the conductive backcoat layer,
The amount of sulfonic acid groups bonded to the aromatic ring is 1 with respect to the aromatic ring.
An electrophotographic lithographic printing plate, which is a conductive composition containing 0 mol% or more of sulfonated polyaniline. 2. The sulfonated polyaniline is aniline,
It is an aniline-based copolymer sulfonate obtained by sulfonation of a copolymer mainly formed from at least one compound selected from the group consisting of aniline derivatives and phenylenediamines and an aminobenzenesulfonic acid compound. The electrophotographic lithographic printing plate according to claim 1, which is characterized in that: 3. The sulfonated polyaniline is aniline,
A aniline-based copolymer sulfonate obtained by copolymerizing at least one compound selected from the group consisting of aniline derivatives and phenylenediamines with an alkoxy group-substituted aminobenzene sulfonic acid compound, wherein An electrophotographic lithographic printing plate according to Item 1. 4. The surface resistance value of the conductive intermediate layer is 1 × 10.
The electrophotographic lithographic printing plate according to claim 1, wherein the electrophotographic lithographic printing plate has a resistance of ² to 1 × 10 ⁸ Ω / □. 5. The surface resistance value of the conductive back coat layer is
The electrophotographic lithographic printing plate according to claim 1, wherein the electrophotographic lithographic printing plate is 1 × 10 ² to 1 × 10 ¹² Ω / □. 6. The support is a void-containing polyester film obtained by at least uniaxially stretching an unstretched sheet material of a mixture of polyester and a thermoplastic resin incompatible with the polyester. The electrophotographic lithographic printing plate according to claim 1, wherein