JP2592309B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor excellent in electrostatic characteristics and moisture resistance. In particular, it relates to a CPC photosensitive member having excellent performance.

(Prior Art) An electrophotographic photosensitive member has various configurations in order to obtain predetermined characteristics or according to the type of an applied electrophotographic process.

Representative electrophotographic photoreceptors include a photoreceptor having a photoconductive layer formed on a support and a photoreceptor having an insulating layer on the surface, and are widely used.

Photoreceptors composed of a support and at least one photoconductive layer are used for image formation by the most common electrophotographic processes, i.e. charging, image exposure and development, and, if necessary, transfer.

Further, a method using an electrophotographic photosensitive member as an offset master for direct plate making has been widely used. In particular, in recent years, direct electrophotographic lithographic printing has become important as a method for printing high-quality printed matter with a print number of several hundreds to several thousands.

The binder used to form the photoconductive layer of the electrophotographic photoreceptor has excellent film forming properties of itself and the ability to disperse the photoconductive powder in the binder, and the formed recording medium layer The adhesion to the substrate is good, and the photoconductive layer of the recording layer has excellent charging ability, low dark decay, large light decay, low pre-exposure fatigue, and changes in humidity during imaging. It is necessary to have various electrostatic characteristics, such as a need to stably maintain the characteristics, and excellent imaging properties.

As long-known resins, for example, silicone resins (Japanese Patent Publication No. 34-6670), styrene-butadiene resins (Japanese Patent Publication No. 35-1960), alkyd resins, maleic acid resins,
Polyamide (Japanese Patent Publication No. 35-11219) vinyl acetate resin (Japanese Patent Publication No. 41-2425), vinyl acetate copolymer (Japanese Patent Publication No. 41-24)
No. 26), acrylic resins (JP-B-35-11216), acrylate copolymers (for example, JP-B-35-11219, JP-B-36-8510, and JP-B-41-13946) are known. I have.

However, in the electrophotographic photosensitive material using these resins, 1) the affinity with the photoconductive powder is insufficient, and the dispersibility of the coating liquid becomes poor. 2) low chargeability of the photoconductive layer;
3) Poor quality of the image portion (particularly halftone dot reproducibility / resolution) of the copied image; 4) The image quality is easily affected by the environment (for example, high temperature, high humidity, low temperature, low humidity, etc.) at the time of creating the copied image. There was a problem.

Various methods have been proposed as a method for improving the electrostatic properties of the photoconductive layer. One of the methods is, for example, a compound containing a carboxyl group or a nitro group on an aromatic ring or a furan ring, or a dicarboxylic acid anhydride. Methods of further combining the materials to coexist in the photoconductive layer are disclosed in JP-B-42-6878 and JP-B-45-3073. However, even the photosensitive materials improved by these methods do not have sufficient electrostatic characteristics, and a material having particularly excellent light attenuation characteristics has not been obtained. Therefore, in order to improve the sensitivity shortage of this photosensitive material,
Conventionally, a method of adding a large amount of a sensitizing dye in a photoconductive layer has been adopted.However, a photosensitive material produced by such a method has a remarkable deterioration in whiteness and a decrease in quality as a recording medium. In some cases, the dark decay of the photosensitive material is deteriorated, and a sufficient copied image cannot be obtained.

On the other hand, Japanese Patent Application Laid-Open No. 60-10254 discloses a method in which the average molecular weight of the resin is adjusted and used as the binder resin used in the photoconductive layer. That is, by using an acrylic resin having an acid value of 4 to 50 and a component having an average molecular weight of 10 ³ to 10 ⁴ and a component having a distribution of 10 ⁴ to 2 × 10 ⁵ , the electrostatic properties (particularly,
A technique for improving repetition reproducibility as a PPC photoreceptor), moisture resistance and the like is described.

Furthermore, research on a lithographic printing original plate using an electrophotographic photoreceptor has been earnestly conducted, and a binder resin for a photoconductive layer having both electrostatic characteristics as an electrophotographic photoreceptor and printing characteristics as a printing original plate. For example, in Japanese Patent Publication No. 50-31011,
Copolymerized with (meth) acrylate monomer and other monomers in the presence of fumaric acid, Tg 10-80 at Mw 1.8-10 × 10 ⁴
C. and a copolymer comprising a (meth) acrylate monomer and a monomer other than fumaric acid. JP-A-53-54027 discloses that a carboxylic acid group is formed by forming at least an atom from an ester bond. Those using a terpolymer containing a (meth) acrylic ester having a substituent which is located at a distance of several sevens, and those disclosed in JP-A-54-20735 and JP-A-57-20254.
No. 4 uses a quaternary or pentameric copolymer containing acrylic acid and hydroxyethyl (meth) acrylate,
JP-A-58-68046 discloses a method using a terpolymer containing a (meth) acrylate ester having an alkyl group having 6 to 12 carbon atoms as a substituent and a carboxylic acid-containing vinyl monomer. It is described that it is effective in improving the desensitizing property of the layer.

(Problems to be Solved by the Invention) However, even if the above-mentioned resin is said to be effective for the electrostatic property and the moisture resistance property, in particular, when actually evaluated, the chargeability, the dark charge retention property, and the photosensitivity are evaluated. However, there was a problem in the electrostatic characteristics as described above, the smoothness of the photoconductive layer, and the like, which were not practically satisfactory.

Even in the case of a binder resin developed as an electrophotographic lithographic printing plate precursor, when actually evaluated, there were problems with the above-described electrostatic properties, background contamination of printed matter, and the like.

Furthermore, the scanning exposure method using a semiconductor laser beam has a longer exposure time than the conventional simultaneous exposure method using visible light, and the exposure intensity is limited. For light and light sensitivity,
Higher performance is required.

The present invention is to improve the problems of the conventional electrophotographic photoreceptor as described above.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a high-quality electrophotographic photoreceptor having improved electrostatic characteristics (particularly dark charge retention and photosensitivity) and reproducing a copied image faithful to an original image.

Another object of the present invention is to provide an electrophotographic photoreceptor having a clear and high-quality image even when the environment at the time of forming a copy image fluctuates such as low temperature and low humidity or high temperature and high humidity.

Another object of the present invention is to provide a CPC electrophotographic photoreceptor having excellent electrostatic characteristics and low environmental dependency.

It is another object of the present invention to provide a lithographic printing plate that provides a printed matter that does not cause background stain at all as an electrophotographic lithographic printing original plate.

(Means for Solving the Problems) The above object is achieved by an electrophotographic photoreceptor having a photoconductive layer containing at least an inorganic photoconductive material and a binder resin.
The binder resin is a polymer having a weight average molecular weight of 1 × 10 ^{3 to} 5 × 10 ⁴ , containing a repeating unit of the following (i) as a polymerization component, and having one end of a polymer main chain. Only −PO ₃ H
₂ group, -SO ₃ H groups, and -COOH groups {R represents a hydrocarbon group having 1 to 10 carbon atoms or -OR '(R' represents a hydrocarbon group having 1 to 10 carbon atoms)}; At least one
It has been found that the problem is solved by an electrophotographic photosensitive member characterized by containing a species.

(I) at least one of the formulas (I) and (II)
More than 30% by weight of one repeating unit (Wherein X ₁ and X ₂ are each independently a hydrogen atom,
Hydrocarbon group having 1 to 10 carbon atoms, chlorine atom, bromine atom, -CO
Y ₁ or -COOY ₂ (Y ₁ and Y ₂ each represents a hydrocarbon group having 1 to 10 carbon atoms) represent.

However, X ₁ and X ₂ are never both represent a hydrogen atom. W ₁
And W ₂ each represent a direct bond or a linking group having 1 to 4 linking atoms, each linking —COO— and a benzene ring. Further, when the resin contained in the binder resin further contains the following repeating unit (ii) as a copolymer component in addition to the above repeating unit (i), the film strength is further improved, It was found that an electrophotographic photoreceptor excellent in printability could be obtained.

(Ii) 1 to 20% by weight of at least one repeating unit containing a heat and / or photocurable functional group In the present invention, each of the repeating units (i) and (ii) is contained in the binder resin in an amount of 2 to 20% by weight. More than one species may be contained.

Conventionally known acidic group-containing binder resins as described above are mainly used for offset masters, and have a large molecular weight (for example, 5 × 10 ⁴ or more) in order to improve printing durability by maintaining film strength. Was a random copolymer, and the copolymer component containing an acidic group was randomly present in the polymer main chain.

On the other hand, the binder resin used in the present invention is a polymer in which an acidic group contained in the resin is bonded to the terminal of the polymer main chain, and further contains a methacrylate component having a specific substituent as a polymerization component. And a copolymer containing a component containing a heat and / or photo-curable functional group as a further copolymer component.

The present inventors, the portion of the terminal acidic group of the polymer main chain,
While adsorbing to the stoichiometric defect of the inorganic photoconductor and improving the covering property of the photoconductor surface, compensating for the trap of the photoconductor and improving the humidity characteristics, the dispersion of the photoconductor is sufficient. In addition to finding that coagulation is suppressed, and by using a specific methacrylate component represented by the formula (I) or (II) of the present invention as a main component of the polymer, electrophotographic properties (chargeability, (DRR, photosensitivity) was remarkably improved, and it was found that the composition exhibited stable high-performance electrophotographic characteristics with little effect on changes in humidity.

Also, the smoothness of the photoconductor surface becomes smooth. When a photoconductor having a rough surface of the photoconductive layer is used as an electrophotographic lithographic printing plate precursor, the dispersion state of the photoconductor particles and the binder resin is not appropriate, and the photoconductive layer is Therefore, even if the desensitizing treatment with the desensitizing solution is performed, the non-image portion is not uniformly and sufficiently hydrophilized, causing adhesion of printing ink during printing, and as a result, the non-image portion of the printed matter is Ground stains occur. On the other hand, in the case of the binder resin according to the present invention, there was a concern that the film strength was weakened.However, by dispersing the photoconductor sufficiently and adsorbing and coating the particle surface, the film property was maintained. It has been found that the film has sufficient film strength as a CPC photoreceptor or an offset master having a printing number of thousands.

When the resin of the present invention further contains at least one kind of heat and / or photocurable functional group, the functional group appropriately crosslinks between the polymers to strengthen the interaction between the polymers, thereby forming a film. Has been found to improve the strength of Therefore, the resin of the present invention, which further contains a heat and / or photocurable functional group, allows the interaction between the binder resin without alienating the appropriate adsorption and coating of the surface of the inorganic photoconductor particles and the binder resin. And, as a result, has the effect of further improving the film strength. That is, by containing at least one kind of heat- and / or photo-curable functional groups and by appropriately crosslinking between polymers in the film, the strength of the film is improved and an offset master plate capable of obtaining a larger number of printed sheets can be obtained. understood.

First, the binder resin provided in the present invention comprises the acidic group,
It is a resin having a weight average molecular weight of 1 × 10 ^{3 to} 5 × 10 ⁴ which is not contained in the side chain linked to the polymer main chain and is bonded only to the terminal of the main chain.

The weight average molecular weight of the resin is preferably 1 × 10 ³ to 2 × 1.
0 ⁴ , more preferably 3 × 10 ³ to 1 × 10 ⁴ .

The photoreceptor using the resin of the present invention exhibits stable high-performance electrophotographic characteristics even when environmental conditions fluctuate significantly from high temperature and high humidity to low temperature and low humidity. When using a resin having a molecular weight of 2 × 10 ⁴ or less,
Higher properties can be maintained.

If the molecular weight of the binder resin is smaller than 1 × 10 ³ , the film-forming ability is reduced, and sufficient film strength cannot be maintained.
If it is larger than × 10 ⁴ , the resin of the present invention cannot maintain electrophotographic properties (particularly, initial potential and dark decay retention) at high humidity, which is not preferable.

The amount of the acidic group present in the polymer is preferably 0.5 to 10 parts by weight, more preferably 2 to 8 parts by weight, per 100 parts by weight of the polymer.

If the content of the acidic group bonded to the terminal of the polymer main chain in the binder resin is less than 0.5% by weight, the initial potential is low and sufficient image density cannot be obtained. On the other hand, when the content of the acidic group is more than 10% by weight, the dispersibility is reduced, the film smoothness and the high humidity property of the electrophotographic properties are reduced, and the background smear increases when used as an offset master.

The glass transition point of the resin of the present invention is preferably in the range of -10C to 110C, more preferably -5C to 90C.

The repeating unit (i) contained in the binder resin of the present invention as a polymerization component or a copolymerization component in an amount of 30% by weight or more is represented by the above formula (I) or (II).

In the formula (I), in addition to a hydrogen atom, a chlorine atom and a bromine atom as preferred X ₁ and X _2, as a preferred hydrocarbon group, an alkyl group having 1 to 4 carbon atoms (eg, a methyl group, an ethyl group, a propyl group) , A butyl group, etc.), an aralkyl group having 7 to 9 carbon atoms (for example, benzyl group, phenethyl group, 3-phenylpropyl group, chlorobenzyl group, dichlorobenzyl group, bromobenzyl group, methylbenzyl group, methoxybenzyl group, chloro- A methyl-benzyl group, etc.), an aryl group (eg, phenyl, tolyl, xylyl, bromophenyl, methoxyphenyl, chlorophenyl, dichlorophenyl, etc.), and -COY ₁
And —COOY ₂ (preferable Y ₁ and Y ₂ include those described as the preferable hydrocarbon groups above). However, neither X ₁ nor X ₂ represents a hydrogen atom.

In the formula (I), W ₁ is a direct bond or —CH _{2 n} (n represents an integer of 1 to 3), —CH ₂ CH ₂ OCO—, CH ₂ O _m (M is 1 or 2
Represents an integer of 1), -CH ₂ CH ₂ O-, etc.
Represents up to 4 linking groups.

W ₂ in the formula (II) represents the same content as W ₁ .

In the present invention, the amount of the monomer corresponding to the repeating unit represented by the formula (I) or (II) is from 30% by weight to 10% by weight.
The content is 0% by weight or less, preferably 60% by weight or more and 100% by weight or less.

Specific examples of the repeating unit (i) represented by the formula (I) or (II) used in the present invention are shown below. But,
The scope of the present invention is not limited to these.

Further, in the acidic group bonded only one terminal of the polymer main chain in the resin of the present invention, preferred acidic groups -PO ₃ H ₂
Group, -SO ₃ H group, -COOH group, It is.

In the above, R represents a hydrocarbon group or OR '(R' represents a hydrocarbon group), and R and R 'preferably have 1 carbon atom.
To 22 aliphatic groups (e.g., methyl group, ethyl group, propyl group, butyl group, hexyl group, octyl group, decyl group,
Dodecyl group, octadecyl group, 2-chloroethyl group, 2
-Methoxyethyl group, 3-ethoxypropyl group, allyl group, crotonyl group, butenyl group, cyclohexyl group, benzyl group, phenethyl group, 3-phenylpropyl group, methylbenzyl group, chlorobenzyl group, fluorobenzyl group, methoxybenzyl group Or an optionally substituted aryl group (eg, phenyl, tolyl, ethylphenyl, propylphenyl, chlorophenyl, fluorophenyl, bromophenyl, chloro-methyl-phenyl, dichlorophenyl, methoxy) Phenyl group,
Cyanophenyl group, acetamidophenyl group, acetylphenyl group, butoxyphenyl group, etc.).

The polymer of the present invention may be synthesized so that the acidic group is bonded to at least the terminal of the main chain of the polymer comprising the polymerization component (i). Specifically, a method using a polymerization initiator containing the acidic group or a functional group that can be converted into the acidic group afterwards, or containing the acidic group or a functional group that can be converted into the acidic group later It can be produced by a method using a chain transfer agent, a method using the both in combination, or a method using an end reaction in an anionic polymerization method to introduce the functional group.

For example, P. Dreyfuss, RPQuirk, Encycl.Polym.Sci.En
g. 7 , 551 (1987), V. Percec, Appl. Polym. Sci. 285 , 95 (1
985), PFRempp, E. Franta, Adv. Polym. Sci. 58, 1 (198
4), Y.Yamashita, J.Appl.Polym.Sci.Appl.Polym.Symp.
36 , 193 (1981), R. Asami, M. Takaki, Makromol. Chem. Sup
pl. 12 , 163 (1985) and the like.

Further, the “heat and / or photocurable functional group” in the repeating unit (ii) that can be preferably contained in the present invention refers to a functional group that performs a resin curing reaction by at least one of heat and light. Say.

In the present invention, when the heat and / or photo-curable functional group-containing copolymer component is present, its amount is preferably 1 to 20% by weight.

If the content of the heat and / or photocurable functional group in the binder resin is less than 1% by weight, the curing reaction is insufficient and the effect of improving the film strength by the curable functional group cannot be obtained. If the content is more than 20% by weight, the degree of curing of the film becomes too high, and the electrophotographic properties are deteriorated.

Specific examples of photocurable functional groups include Hideo Inui and Mototaro Nagamatsu, “Photosensitive Polymers” (Kodansha, 1977), Takahiro Tsunoda,
"New photosensitive resin" (publishing department of printing society, 1981), GE
Green and BP, Strark, J.Macro.Sci.Reas.Macro Chem.,
C21 (2), 187-273 (1981-82), CGRattey, Photopo
lymerization of Surface Coatings (A. Wiley InterSci
ence Pub. 1982), and functional groups used in conventionally known photosensitive resins and the like are used as photocurable resins.

Further, the “thermosetting functional group” in the present invention is a functional group other than the above-mentioned acidic group, and includes, for example, Tsuyoshi Endo, “Refinement of thermosetting polymer” (CMC Corporation, 1986), Yuji Harazaki, "Handbook of Latest Binder Technologies", Chapter II-I (Comprehensive Technology Center, published in 1985), Takayuki Otsu, "Synthesis and Design of Acrylic Resins and Development of New Applications" (Chubu Business Development Center Publishing Division,
1985), Emori Omori "Functional Acrylic Resin" (Techno System, 1985), and the like can use the functional groups of the references.

For example -OH group, -SH group, -NH _2, -NHR ₁ group [R ₁ represents a hydrocarbon group, for example an optionally substituted alkyl group (e.g. methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl Group, butyl group, hexyl group, octyl group, decyl group, 2
-Chloroethyl group, 2-methoxyethyl group, 2-cyanoethyl group, etc.), C4-8 optionally substituted cycloalkyl group (e.g., cycloheptyl group, cyclohexyl group, etc.), C7-12 substituted group. Aralkyl groups (eg, benzyl group, phenethyl group, 3-phenylpropyl group, chlorobenzyl group, methylbenzyl group, methoxybenzyl group, etc.), and optionally substituted aryl groups (eg, phenyl group, tolyl group, xylyl group) Chlorophenyl group, bromophenyl group, methoxyphenyl group, naphthyl group, etc.) -CONHCH ₂ OR ₂ [R ₂ represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms (eg, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, etc.)], -N =
C = O group and {A ₁ and a ₂ each represent a hydrogen atom, a halogen atom (eg, a chlorine atom, a bromine atom, etc.) or an alkyl group having 1 to 4 carbon atoms (eg, a methyl group, an ethyl group, etc.)} and the like. . As the polymerizable double bond group, specifically,
CH ₂ = CH-, CH ₂ = CH-CH _2- , CH ₂ = CH-CONH-, _{CH 2 = CH-NHCO-, CH} 2 = CH-CH 2 -NHCO-, CH 2 = CH-SO
_{2 -, CH 2 = CH-} CO-, CH 2 = CH-O-, may be mentioned CH ₂ = CH-S-, and the like.

In the present invention, as a method for causing the binder resin to contain at least one functional group selected from the group of the curable functional groups, a method of introducing the functional group into a polymer by a polymer reaction, or the method of introducing the functional group It can be obtained by, for example, a method of copolymerizing one or more monomers and a monomer corresponding to the repeating unit of the above general formula (I) or (II).

For the high-molecular reaction, a conventionally known low-molecular-weight synthesis reaction method can be used as it is. For example, the Chemical Society of Japan, “New Experimental Chemistry Course, Vol. 14, Synthesis and Reaction of Organic Compounds [I]-
[V] "(published by Maruzen Co., Ltd.)," Reactive Polymers "by Yoshio Iwakura and Keisuke Kurita, etc. are described in detail in publicly known literature and the like.

On the other hand, the "functional group which performs light and / or heat curing reaction"
Examples of the monomer containing a functional group include a vinyl compound containing the functional group, which can be copolymerized with a monomer corresponding to the repeating unit of the general formula (I) or (II). . For example, it is described in “Polymer Data Handbook [Basic Edition]” edited by The Society of Polymer Science, Baifukan (1986). Specifically, acrylic acid, α- and / or β-substituted acrylic acid (for example, α-acetoxy form, α-acetoxymethyl form, α- (2-amino) methyl form, α-chloro form, α-form
-Bromo form, α-fluoro form, α-tributylsilyl form,
α-cyano form, β-chloro form, β-bromo form, α-chloro-β-methoxy form, α, β-dichloro form, etc.), methacrylic acid, itaconic acid, itaconic acid half esters, itaconic acid half amides , Crotonic acid, 2-alkenylcarboxylic acids (eg, 2-pentenoic acid, 2-methyl-2-hexenoic acid, 2-octenoic acid, 4-methyl-2-hexenoic acid,
4-ethyl-2-octenoic acid, etc.), maleic acid, maleic acid half-esters, maleic acid half-amides, vinylbenzene carboxylic acid, vinylbenzene sulfonic acid, vinyl sulfonic acid, vinyl phosphonic acid, vinyl group of dicarboxylic acids or Examples include half ester derivatives of allyl groups, ester derivatives of these carboxylic acids or sulfonic acids, and compounds containing the acidic group in the substituents of the amide derivatives.

The repeating unit (ii) containing a "heat / photocurable functional group" will be exemplified.

Further, the resin of the present invention may contain a monomer corresponding to the repeating unit of the general formula (I) or (II), and a monomer containing an optional light and / or thermosetting functional group,
A monomer other than these may be contained as a copolymer component.

For example, methacrylic acid esters, acrylic acid esters, crotonic acid esters, itaconic acid diesters (the ester group of each of these unsaturated carboxylic acids,
For example, methyl, ethyl, propyl, butyl, heptyl, hexyl, octyl, decyl, dodecyl, 2-hydroxyethyl, 2-chloroethyl,
2-methoxyethyl group, methoxymethyl group, ethoxymethyl group, 2,3-dihydroxypropyl group, 2- (N, N-dimethylamino) ethyl group, 2- (N-morpholino) ethyl group, 2-furylethyl group Benzyl group, phenethyl group, cyclohexyl group, phenyl group, etc.), α-olefins, vinyl alkanoate or allyl esters, acrylonitrile, methacrylonitrile, vinyl ethers,
Acrylamides, methacrylamides, styrenes,
Heterocyclic vinyls (eg, vinylpyrrolidone, vinylpyridine, vinylimidazole, vinylthiophene, vinylimidazoline, vinylpyrazole, vinyldioxane,
Vinylquinoline, vinylthiazole, vinyloxazine, etc.).

In the present invention, a reaction accelerator may be added, if necessary, in order to promote a crosslinking reaction in the photosensitive layer film, particularly when the photosensitive layer contains a light and / or thermosetting functional group. In the case of a reaction mode for forming a chemical bond between functional groups, for example, an organic acid (acetic acid, propionic acid, butyric acid, benzenesulfonic acid, p-toluenesulfonic acid, etc.) cross-linking agent and the like can be mentioned.

Specific examples of the cross-linking agent include compounds described in Shinzo Yamashita and Tosuke Kaneko, “Cross-Linking Agent Handbook”, Taiseisha (1981) and the like. For example, commonly used crosslinking agents such as organic silane, polyurethane, and polyisocyanate, and curing agents such as epoxy resin and melamine resin can be used.

In the case of the polymerization reaction mode, a polymerization initiator (peroxide,
Azobis-based compounds and the like, preferably azobis-based polymerization initiators), and monomers having a polyfunctional polymerizable group (for example, vinyl methacrylate, allyl methacrylate, ethylene glycol diacrylate, polyethylene glycol diacrylate, divinyl succinate) Acid esters, divinyl adipates, diallylsuccinates, 2-methylvinyl methacrylate, divinylbenzene, etc.).

Further, in the case of a resin containing a photocrosslinkable functional group, a sensitizer, a photopolymerizable monomer and the like may be added. Specifically, compounds and the like cited in the above-mentioned review on photosensitive resins can be used.

In the present invention, when a binder resin containing a thermosetting functional group is used, a thermosetting treatment is performed. This thermosetting treatment can be performed by strictly setting the drying conditions at the time of the conventional photoreceptor production. For example, the treatment may be performed at 60 ° C. to 120 ° C. for 5 minutes to 120 minutes. When using a resin containing a photocrosslinkable functional group, after coating the photosensitive layer-forming product, it is crosslinked by irradiating with an electron beam, X-ray, ultraviolet light or plasma light, which is not only during drying but also during drying. Either before or after, the reaction is further accelerated by heating under the above drying conditions. When containing a heat and / or photo-curable functional group, when the above reaction accelerator is used in combination,
Processing can be performed under milder conditions.

Examples of the inorganic photoconductive material used in the present invention include zinc oxide, titanium oxide, zinc sulfide, cadmium sulfide, cadmium carbonate, zinc selenide, cadmium selenide, tellurium selenide, and lead sulfide. Preferably, zinc oxide, titanium oxide and the like are used. The total amount of the binder resin used for the inorganic photoconductive material is a ratio of 10 to 100 parts by weight of the binder resin to 100 parts by weight of the photoconductor, preferably 15 to 5 parts.
Used at 0 parts by weight.

In the present invention, various dyes can be used as spectral sensitizers as needed. For example, Harumiya Miyamoto: Hidehiko Takei: Imaging 1973 (N.8), page 12, CJ Young, RC
A Review 15, 469 (1954) Wataru Kiyota equality, Telecommunications Society of J63-C (No.2), 97 (1980), Yuji like Yuji, Industrial Chemistry Journal 66, 78 and 188 (1963), Tadaaki Tani, Journal of the Photographic Society of Japan 3
5 , 208 (1972), etc., such as carbonium dyes, diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, phthalein dyes, polymethine dyes (eg, oxonol dyes, merocyanine dyes, cyanine dyes, rhodacyanine dyes, styryl dyes, etc.) ), Phthalocyanine dyes (which may contain a metal), and the like.

More specifically, those using mainly carbonium dyes, triphenylmethane dyes, xanthene dyes, and phthalein dyes are described in JP-B-51-452,
0-90334, JP-A-50-114227, JP-A-53-39130
And JP-A-53-82353, U.S. Pat. No. 3,052,540, U.S. Pat. No. 4,054,450, and JP-A-57-16456.

Oxonol dyes, merocyanine dyes, cyanine dyes, polymethine dyes such as rhodacyanine dyes, F.
M. Hamer, `` The Cyanine Dyes and Related Compound
s '' can be used, and more specifically, U.S. Pat.No. 3,047,384, U.S. Pat.No. 3,110,591, U.S. Pat.No. 3,121,008, U.S. Pat.
No. 28179, U.S. Pat.No. 3,313,942, U.S. Pat.No. 3,622,317
No., British Patent No. 1226892, British Patent No. 1309274, British Patent No. 1405898, JP-B-48-7814, JP-B-55-18892
And the like.

Further, as a polymethine dye for spectrally sensitizing the near infrared to infrared light region having a long wavelength of 700 nm or more, JP-A-47-840, JP-A-47-44180, JP-B-51-41061, 1949-5034
No., JP-A-49-45122, JP-A-57-46245, JP-A-56
No. -35141, JP-A-57-157254, JP-A-61-26044,
JP-A-61-27551, U.S. Pat.No. 3,619,154, U.S. Pat.
4175956, "Research Disclosure", 1982, 216, No. 1
And those described on pages 17 to 118 and the like.

The photoreceptor of the present invention is also excellent in that even when various sensitizing dyes are used in combination, the performance is not easily changed by the sensitizing dye.

Furthermore, various conventionally known additives for an electrophotographic photosensitive layer such as a chemical sensitizer can be used in combination, if necessary. For example, the review mentioned above: Imaging 1973 (No. 8)
"Recent development and commercialization of photoconductive materials and photoreceptors", e.g., electron accepting compounds (eg, halogen, benzoquinone, cranyl, acid anhydride, organic carboxylic acid, etc.) and Hiroshi Komon in the reviews on page 12. Chapters 4 to 6: Polyarylalkane compounds, which are referred to in the review section of Japan Science Information Co., Ltd. Publishing Division (1986)
Hindered phenol compounds, p-phenylenediamine compounds, and the like.

The amount of these various additives is not particularly limited,
Usually, it is 0.0001 to 2.0 parts by weight based on 100 parts by weight of the photoconductor.

The thickness of the photoconductive layer is preferably from 1 to 100 μm, particularly preferably from 10 to 50 μm.

When a photoconductive layer is used as the charge generation layer of the photoreceptor in which the charge generation layer and the charge transport layer are stacked, the thickness of the charge generation layer is preferably 0.01 to 1 μm, particularly preferably 0.05 to 0.5 μm.

Examples of the charge transport material of the laminated photoreceptor include polyvinyl carbazole, oxazole dyes, pyrazoline dyes, and triphenylmethane dyes.

The thickness of the charge transport layer is 5 to 40 μm, particularly 10 to 30 μm.
m is preferred.

As the resin used for forming the insulating layer or the charge transport layer, typical ones are polystyrene resin, polyester resin, cellulose resin, polyether resin, vinyl chloride resin, vinyl acetate resin, polyvinyl chloride copolymer resin, A thermoplastic resin and a curable resin such as a polyacryl resin, a polyolefin resin, a urethane resin, an epoxy resin, a melamine resin, and a silicone resin are appropriately used.

The photoconductive layer according to the present invention can be provided on a conventionally known support. Generally speaking, the support of the electrophotographic photosensitive layer is preferably electrically conductive. As the conductive support, as in the conventional case, for example, a substrate such as metal, paper, or a plastic sheet is impregnated with a low-resistance substance. A substrate that has been subjected to a conductive treatment, for example, by applying a conductivity to the back surface of the substrate (the surface opposite to the surface on which the photosensitive layer is provided), and further coated with at least one layer for the purpose of preventing curling and the like. A substrate provided with a water-resistant adhesive layer on its surface, a substrate provided with at least one or more precoat layers as necessary on the surface layer of the support, or a substrate conductive plastic on which Al or the like is deposited is laminated on paper. Can be used.

Specifically, as an example of a conductive substrate or a conductive material, Yukio Sakamoto, Electrophotography, 14, (No. 1), pp. 2-11 (1975), Hiroyuki Moriga, "Chemistry of Introductory Specialty Paper," Molecular Publishing Association (1975), MFHoover, J. Macromol. Sci, Chem. A-4
(6), and those described in pages 1327 to 1417 (1970) and the like are used.

(Examples) Examples of the present invention will be described below, but the contents of the present invention are not limited thereto.

Example 1 and Comparative Examples A and B (Synthesis Example 1) 2-chloro-6-methylphenyl methacrylate 95
g, a mixed solution of 150 g of toluene and 50 g of isopropanol was heated to a temperature of 80 ° C. under a nitrogen stream, and 5 g of 4,4′-azobis (4-cyanovaleric acid) (hereinafter abbreviated as ABCV) was added, followed by 10 hours. Reacted.

The weight average molecular weight of the obtained copolymer (P-1) was 6,50.
0, the glass transition point was 40 ° C.

Structure of resin (P-1) (Synthesis Example 2) After heating a mixed solution of 95 g of ethyl methacrylate, 5 g of acrylic acid and 200 g of toluene to a temperature of 90 ° C under a nitrogen stream, 2,2'-azobis (2,4-dimethylvaleronitrile)
6 g was added and reacted for 10 hours. Obtained copolymer (A)
Had a weight average molecular weight of 7,800 and a glass transition point of 45 ° C.

(Synthesis Example 3) A mixed solution of 98 g of ethyl methacrylate, 2 g of acrylic acid and 200 g of toluene was heated to a temperature of 75 ° C under a nitrogen stream, and 1.5 g of 2,2'-azobis (isobutyronitrile) was added. Allowed to react for hours. The weight average molecular weight of the obtained copolymer (B) was 32,000, and the glass transition point was 45 ° C.

Example 1 40 g (as solid content) of the copolymer (P-1) produced in Synthesis Example 1, 200 g of zinc oxide, 0.02 g of a heptamethine cyanine dye represented by the following structural formula, 0.05 g of phthalic anhydride, and 300 g of toluene The mixture was dispersed in a ball mill for 2 hours to prepare a photosensitive layer-formed product, which was applied to a conductive treated paper with a wire bar so that the dry adhesion amount was 18 g / m ² ,
Dry at 30 ° C for 30 seconds. Then, it was left standing in a dark place at 20 ° C. and 65% RH for 24 hours to prepare an electrophotographic photosensitive material.

Comparative Example A In place of the copolymer (P-1) used in Example 1, 40 g (as solid content) of the copolymer (A) produced in Synthesis Example 2
A comparative electrophotographic photoreceptor A was produced in the same manner as in Example 1 except for using.

Comparative Example B In place of the copolymer (P-1) used in Example 1, 40 g (as a solid content) of the copolymer (B) produced in Synthesis Example 3
An electrophotographic photosensitive member B for comparison was produced in the same manner as in Example 1 except for using the same.

The film properties (surface smoothness), electrostatic properties, imaging properties, and imaging properties when the environmental conditions were set to 30 ° C. and 80% RH were examined for these photosensitive materials. Further, when these photosensitive materials are used as an offset master, the photoconductive desensitizing property (expressed by the contact angle of the photoconductive layer with water after the desensitizing treatment) and printability (ground stain, Printing durability).

The image-capturing property and printability were determined by exposing and developing a fully automatic plate making ELP404V (manufactured by Fuji Photo Film Co., Ltd.) using a developer ELP-T to form an image, and using a desensitizing liquid ELP-E. The examination was carried out using a lithographic printing plate obtained by etching with an etching processor (a Hamadastar 800SX type manufactured by Hamadastar Co., Ltd. was used as a printing machine).

 Table 1 summarizes the above results.

The embodiments of the evaluation items shown in Table 1 are as follows.

Note 1) Smoothness of photoconductive layer: The obtained photosensitive material was measured for its smoothness (sec / cc) using a Beck smoothness tester (manufactured by Kumagaya Riko Co., Ltd.) under the condition of an air capacity of 1 cc. It was measured.

Note 2) Electrostatic properties: Paper analyzer (Kawaguchi Electric Co., Ltd. paper analyzer) in a dark room at a temperature of 20 ° C and 65% RH.
After the 20 seconds corona discharge -6kV with SP-428 type), allowed to stand for 10 seconds to measure the surface potential V ₁₀ at this time.
Next, the potential V ₉₀ after standing still in the dark for 90 seconds was measured, and the potential holding after dark decay for 90 seconds, that is, the dark decay retention rate [DRR (%)] was calculated as (V ₉₀ / V ₁₀ ) x 100 (%)
I asked for it. Also, the surface of the photoconductive layer is -400 V by corona discharge.
After that, the surface of the photoconductive layer is irradiated with a gallium-aluminum-arsenic semiconductor laser (oscillation wavelength: 830 nm), and the time until the surface potential (V ₁₀ ) is reduced to 1/10 is determined. Calculate the amount E _1/10 (erg / cm ² ).

Environmental conditions at the time of measurement are 20 ℃, 65% RH (I) and 30 ℃, 80%
Performed at RH (II).

Note 3) Imaging properties: After each photosensitive material was left for one day and night under the following environmental conditions, each photosensitive material was charged at -6 KV, and a 2.8 mW output gallium-aluminum-arsenic semiconductor laser (oscillation wavelength)
830 nm) on a photosensitive material surface at an irradiation dose of 64 erg / cm ² at a pitch of 25 μm and a scanning speed of 300 m / sec, and ELP-T (Fuji Photo Film Co., Ltd.) )), And the copied image (fog, image quality) obtained by developing and fixing was visually evaluated. Environmental conditions during imaging are 20 ° C 65% RH (I) 30 ° C 80%
Performed at RH (II).

Note 4) Contact angle with water: Each photosensitive material was treated with a desensitizing solution ELP-E (manufactured by Fuji Photo Film Co., Ltd.) using an etching processor.
After passing through the surface of the photoconductive layer to desensitize the surface, a drop of 2 μl of distilled water is placed on the surface, and the contact angle with the formed water is measured with a goniometer.

Note 5) Printing durability After plate-making in the same manner as in the imaging performance of Note 3) above, desensitizing treatment was performed under the same conditions as in Note 4) above, and this was used as an offset master in an offset printing machine (Sakurai Seisakusho Co., Ltd.) It shows the number of sheets that can be printed using high quality paper as printing paper without causing any problems in the background of the non-image part of the printed matter and the image quality of the image part. (The larger the number of printed sheets, the better the printing durability. Good thing).

Note 6) DM (image density): Indicates the maximum value of the solid toner image density (measureable by Macbeth reflection density). As shown in Table 1, the photosensitive material of the present invention has a smoothness of the photoconductive layer. Also, the electrostatic characteristics were good, and the actual copied image had no ground fog and the copied image quality was clear. This is presumed to be due to the photoconductor and the binder resin being sufficiently adsorbed and covering the particle surface. For the same reason, even when used as an offset master master, the desensitizing treatment with the desensitizing solution proceeds sufficiently, the contact angle with water of the non-image area is as small as 15 degrees or less, and the hydrophilicity is sufficiently increased. You can see that Even when the printed matter was actually printed and the background stain was observed, no background stain was observed.

On the other hand, Comparative Example A using a random copolymer having a low molecular weight containing an acid component as a side chain of the random copolymer, and having ethyl methacrylate as a copolymer component,
Looking at the electrostatic characteristics at normal temperature and normal humidity and the printing characteristics using the plate, it was possible to obtain a copied image and a printed image within a range where the image quality did not deteriorate.

However, under high temperature and high humidity, the electrostatic characteristics deteriorate, and V ₁₀ , D.
Both RR and E _1/10 decreased, and the actual copied image was not of sufficient quality.

Comparative Example B, which is the same [ethyl methacrylate / acrylic acid] copolymer as Comparative Example A and has a large weight-average molecular weight, has extremely poor photoconductive layer smoothness,
In addition, the electrostatic properties, especially the DRR, deteriorated (the apparently small value of E _1/10 is due to the low DRR).
Even when used as an offset original plate, the contact angle with water of the non-image area after desensitization treatment was as large as 25 to 35 degrees, and there was variation. Even when printing was actually performed, background staining was generated from printing. This is presumed to be due to the fact that the molecular weight of the binder resin increases, causing aggregation between the particles and adsorption to the photoconductor particles, resulting in an adverse effect.

As described above, an electrophotographic photosensitive member that satisfies electrostatic characteristics and printability only when the resin of the present invention is used is obtained.

Examples 2 to 23 As resins, copolymers shown in Table 2 were produced in the same manner as in the production conditions of Synthesis Example 1.

The weight average molecular weight of each of the obtained resin examples P-2 to P-23 was 6,000 to 8,000.

Each photoreceptor was manufactured in the same manner as in Example 1 except that 40 g (as solid content) of each resin shown in Table 2 was used instead of 40 g of the copolymer (P-1) used in Example 1. Each characteristic was measured in the same manner as in Example 1. The surface of the photoconductive layer of each photoreceptor was smooth at 80 (sec / cc) or more.
The results regarding the electrostatic characteristics and the imaging properties are also shown in Table-2.

All photosensitive materials of the present invention are chargeable, dark charge retention,
Excellent light sensitivity, real copy image is high temperature and humidity (30 ℃, 80%
Even under very severe conditions (RH), a clear image was obtained without occurrence of ground fogging or fine line skipping.

Example 24 A mixed solution of 97 g of 2,6-dichlorophenyl methacrylate, 3 g of thioglycolic acid, 150 g of toluene and 50 g of isopropanol was heated to a temperature of 65 ° C. under a nitrogen stream, and then 0.8 g of azobisisobutyronitrile was added thereto for 8 hours. Reacted. The weight average molecular weight of the obtained copolymer (P-24) was 7,800, and the glass transition point was 36 ° C.

Structure of Resin P-24 The same procedure as in Example 1 was repeated, except that 40 g of the above copolymer (P-24) (in terms of solid content) was used instead of 40 g of the copolymer (P-1) used in Example 1. A body was manufactured, and each property was measured in the same manner as in Example 1. The photoconductive layer surface of each photoreceptor had a smoothness of 80 (sec / cc). V
₁₀ ; −740 V, DRR; 88%, E _1/10 20 (erg / cm ² )
(30 ° C., 80% RH), the imaging performance was good.

The light-sensitive material of the present invention is excellent in chargeability, dark charge retention rate, and light sensitivity, and the occurrence of ground fogging and fine line skipping even under severe conditions of high temperature and high humidity (30 ° C., 80% RH) in actual copied images. Gave a clear image without any etc.

Examples 25 to 30 Copolymers were synthesized under the same conditions as in Example 24 except that the thioglycolic acid used in Example 24 was changed to the compounds shown in Table 3.

Each of these copolymers was processed under the same conditions as in Example 1 to produce each photosensitive material.

 All of the photoreceptors of the present invention exhibited excellent characteristics.

Example 31 As a resin of the present invention, a copolymer having the following chemical structure (P-
31) was used.

Resin (P-31) 40 g of the resin, zinc oxide 200 g, rose bengal 0.03 g, tetrabromophenol blue 0.02 g, phthalic anhydride 0.01 g
And 300 g of toluene were dispersed in a ball mill for 2 hours. Next, 10 g of allyl methacrylate and 0.5 g of 2,2'-azobisisobutyronitrile were added to this dispersion and dispersed in a ball mill for 10 minutes to prepare a photosensitive layer-formed product.

This is applied to a conductive treated paper with a wire bar so that the dry adhesion amount becomes 22 g / m ^2, and then at 80 ° C. for 1 hour and further at 100 ° C.
For 30 minutes. Then, it was left standing in a dark place at 20 ° C. and 65% RH for 24 hours to prepare an electrophotographic photosensitive member.

The obtained photosensitive material was measured for electrostatic characteristics in the same manner as in Example 1. However, after the optical attenuation amount of exposure (E _1/10) is obtained by charging a photoconductive layer surface to -400V by the corona discharge, irradiation with photoconductive layer surface with visible light illumination 2.0 lux, the surface potential (V ₁₀ ) Was reduced to 1/10, and the exposure amount E _1/10 (looks / second) was calculated from this.

V ₁₀ : −560 V, DRR = 87%, E _1/10 = 8.31 ux · sec.

Further, when this was subjected to plate making using an ELP-T toner with a fully automatic plate making machine ELP404V, the density of the obtained master plate for offset printing was 1.0 or more, and the image quality was clear. Further, after the etching process and printing with a printing machine, the printed matter after printing 7000 sheets had no fog in the non-image area and the image was clear. The electrostatic properties, imaging properties and printability were similarly measured under the environmental conditions of (30 ° C., 80% RH), but no difference was found between the room temperature and the normal humidity.

Examples 32 to 37 The procedure of Example 31 was repeated, except that the copolymer (P-31) of the present invention was replaced with a copolymer shown in Table 4 below, and each of the electronic components was used. A photographic light-sensitive material was prepared.

When this was subjected to plate-making using the same apparatus as in Example 31, the density of the obtained master plate for offset printing was 1.0 or more, and the image quality was clear. Further, after printing with a printing machine after etching, the printed matter after printing 7,000 sheets had clear image quality without fog.

Examples 38 and 39 Preparation of each photosensitive material in the same manner as in Example 31 except that the copolymer shown in Table 5 below was used instead of the resin (P-31) of the present invention. did. However, the drying condition after application was 110 ° C. for 2 hours.

This was made into a plate using the same apparatus as in Example 31, then etched, and printed with a printing machine. The density of the master plate for offset printing obtained after plate making was 1.1 or more, and the image quality was clear. The image quality of the printed matter after printing 5,000 sheets was clear with no ground fog.

(Effects of the Invention) According to the present invention, it is possible to obtain an electrophotographic photoreceptor having excellent photoconductive layer smoothness, electrostatic properties, image-capturing property, desensitizing property and background fouling. Even under severe conditions as described below, these excellent properties are maintained.

Furthermore, the photosensitive material of the present invention has a sufficiently high printing durability of about several thousand sheets. When the binder resin further contains a copolymer component containing a heat and / or photocurable functional group, such printing durability is further improved.

Claims (2)

(57) [Claims] 1. An electrophotographic photosensitive member having a photoconductive layer containing at least an inorganic photoconductive material and a binder resin, wherein the binder resin has a weight average molecular weight of 1 × 10 ^{3 to} 5 × 10 ^4. A polymer containing a repeating unit of the following (i) as a polymerization component, and -PO ₃ H only at one end of the polymer main chain:
₂ group, -SO ₃ H groups, and -COOH groups R represents a hydrocarbon group having 1 to 10 carbon atoms or -OR '(R' represents a hydrocarbon group having 1 to 10 carbon atoms). At least one
An electrophotographic photoreceptor characterized by containing species. (I) 30% by weight or more of at least one repeating unit represented by the formula (I) or the formula (II) (Wherein X ₁ and X ₂ are each independently a hydrogen atom,
Hydrocarbon group having 1 to 10 carbon atoms, chlorine atom, bromine atom, -CO
Y ₁ or -COOY ₂ (Y ₁ and Y ₂ each represents a hydrocarbon group having 1 to 10 carbon atoms) represent. However, X ₁ and X ₂ are never both represent a hydrogen atom. W ₁ and W ₂ each connect -COO- and a benzene ring,
It represents a direct bond or a linking group having 1 to 4 linking atoms. ) 2. The resin according to claim 1, wherein the resin contained in the binder resin further contains a repeating unit of the following (ii) as a copolymer component in addition to the repeating unit of (i). Electrophotographic photoreceptor. (Ii) 1 to 20% by weight of at least one repeating unit containing a heat and / or photocurable functional group