JP2581952B2 - Photoconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoreceptor, for example, to an electrophotographic photoreceptor.

B. 2. Description of the Related Art In the electrophotographic copying method of the Carlson method, after charging a photoreceptor surface, an electrostatic latent image is formed by exposure, and the electrostatic latent image is developed with toner. Transfer and fix to At the same time, the photoreceptor is subjected to removal of attached toner, static elimination, and surface cleaning,
Used repeatedly over a long period.

Therefore, the electrophotographic photoreceptor has not only electrophotographic characteristics such as good charging characteristics and sensitivity and low dark decay, but also physical characteristics such as printing durability, abrasion resistance and moisture resistance in repeated use. It is also required to have good properties, ozone generated at the time of corona discharge, resistance to ultraviolet rays at the time of exposure (environmental resistance).

Conventionally, selenium, zinc oxide,
Inorganic photoreceptors are widely used for a photosensitive layer containing an inorganic photoconductive substance such as cadmium sulfide as a main component.

On the other hand, utilization of various organic photoconductive substances as materials for a photosensitive layer of an electrophotographic photosensitive member has been actively developed and studied in recent years.

For example, Japanese Patent Publication No. Sho 50-10496 describes an organic photoreceptor having a photosensitive layer containing poly-N-vinylcarbazole and 2,4,7-trinitro-9-fluorenone. However, this photoreceptor is not always satisfactory in sensitivity and durability. In order to improve such disadvantages, an attempt has been made to develop an organic photoreceptor having high sensitivity and high durability by separately assigning a carrier generation function and a carrier transport function to different substances in the photosensitive layer. ing. In such a so-called function-separated type electrophotographic photoreceptor, since a material exhibiting each function can be selected from a wide range, an electrophotographic photoreceptor having arbitrary characteristics can be relatively easily produced. It is possible. Therefore, it is expected that an organic photoreceptor having high sensitivity and high durability can be obtained.

In the photosensitive layer of such an electrophotographic photoreceptor, by using a carrier generating substance and a polymer binder together,
Efforts have been made to obtain an electrophotographic photoreceptor having excellent electrophotographic properties and film strength.

At this time, the carrier generating substance is dissolved or dispersed in the polymer binder, and the generated photocarrier is transported in the layer. Therefore, depending on the type of the polymer binder, the photocarrier transport ability in the layer is greatly affected.
Therefore, selection of the polymer binder is a very important factor that governs the photosensitivity of the photoreceptor. However, there is no general rule for uniform selection of the binder, and the fact is that the binder is selected through repeated experiments in consideration of the type of the carrier generating substance and the like.

On the other hand, even with a polymer binder capable of providing an electrophotographic photoreceptor having excellent electrical characteristics, the liquid properties and stability of the coating solution when the photosensitive layer is formed by coating may not be sufficient. In the case of dip coating, the uniformity of the coating layer was insufficient microscopically, and the electrophotographic characteristics of the obtained electrophotographic photoreceptor sometimes became uneven.

C. It is an object of the present invention to provide a photoreceptor which is excellent in photosensitivity, has good coatability of a layer containing a carrier-generating substance, and can provide a uniform and high-quality image.

D. Configuration of the invention and its effects The present invention contains a carrier-generating substance, a resin other than a vinyl chloride resin, and 0.2 to 30 parts by weight of a vinyl chloride resin based on 100 parts by weight of the resin other than the vinyl chloride resin. The present invention relates to a photoreceptor comprising a layer having increased light sensitivity.

In the present invention, the binder resin of the layer containing the carrier generating substance has a remarkable feature.

That is, it is important that the vinyl resin is added to the “resin other than the vinyl chloride resin” as the binder resin, and that both are used in combination.

Various studies have been made on the binder resin itself of the layer containing the carrier-generating substance as described above.

On the other hand, in the present invention, a vinyl chloride resin is also added to the binder resin (resin other than the vinyl chloride resin) of the “layer containing a carrier generating substance”. As a result,
As a result of significantly improving the photosensitivity of the photoreceptor and the applicability of the "layer containing a carrier-generating substance", uniform and fine image defects (non-uniform fog, lowering of the degree of blackening of solid black portions, etc.) ), And a high-quality image in which suppression was achieved was obtained.

The reason for the higher sensitivity may be to improve the range probability of photocarriers, for example, by controlling the junction state at the interface, controlling the electric field effect, controlling the transport site, and reducing the number of trap sites. The reason for the high quality of the image is presumed to be the uniformity of the coating film due to the change in physical properties (viscosity, flow characteristics, etc.) of the coating solution due to the interaction of the binder and the CGM = binder interaction. However, these causes are not always clear.

Moreover, as described later, it has been confirmed that the photosensitivity and the applicability of the “layer containing a carrier-generating substance” are remarkably improved only by adding a small amount of the vinyl chloride resin. I can say that.

The photoreceptor of the present invention comprises, for example, a carrier containing a carrier generating substance (CGM) and a binder resin on a support 1 (a conductive support or a sheet provided with a conductive layer) as shown in FIG. A carrier transporting layer 3 (hereinafter, referred to as a CGL) containing a carrier transporting substance (CTM) and, if necessary, a binder resin as a lower layer with a generating layer 2 (hereinafter, may be referred to as CGL).
Photosensitive layer 4 with layered structure with CTL)
A provided, as shown in FIG.
3 is a lower layer and CGL2 is an upper layer and a laminated photosensitive layer 4B is provided. As shown in FIG.
And a single-layer photosensitive layer 4D containing a binder resin as necessary, and a protective layer 5 provided on a laminated photosensitive layer 4B (see FIG. 2) as shown in FIG. And the like.

The CGL may contain both CGM and CTM, and a protective layer (OCL) may be provided on the photosensitive layers 4A and 4D. An intermediate layer and an undercoat layer may be provided between the support and the photosensitive layer. It may be provided.

The “layer containing a carrier-generating substance” is shown in FIGS.
In the example of the figure, it corresponds to the carrier generation layer 2 and the photosensitive layer 4D.

In the `` layer containing a carrier-generating substance '', when the content of CGM is 100 parts by weight, the content of the `` resin other than the vinyl chloride resin '' is preferably 10 to 500 parts by weight, and 20 to 300 parts by weight. It is even better if it is by weight. Also,
The content of the "vinyl chloride resin" is preferably 0.1 to 250 parts by weight, more preferably 0.2 to 150 parts by weight.
Similarly, the content of CTM is preferably from 0 to 500 parts by weight, more preferably from 0 to 300 parts by weight.

Further, when the content of the “resin other than the vinyl chloride resin” in the “layer containing the carrier generating substance” is 100 parts by weight, the content of the “vinyl chloride resin” is 0.02 to 50.
It is preferably set to 0.1 parts by weight, more preferably 0.1 to 40 parts by weight, and even more preferably 0.2 to 30 parts by weight.

The "vinyl chloride-based resin" includes vinyl chloride-based copolymer resins in addition to vinyl chloride resins produced by polymerization of vinyl chloride monomers.

Other copolymerizable monomers that can be copolymerized as needed include known polymerizable monomers, for example, vinyl alcohol, various vinyl esters such as vinyl acetate and vinyl propionate, vinylidene chloride, acrylonitrile, and methacryloyl. Nitrile, styrene, various acrylic acid methacrylic acid, acrylic acid ester, methacrylic acid ester, (meth) hydroxyacryl acrylate, ethylene, propylene, isobutene, butadiene, isoprene, vinyl ether, aryl ether, aryl ester, acrylamide, methacrylamide, maleic Acid esters and the like are exemplified.

As the vinyl chloride copolymer, preferably, a copolymer containing vinyl chloride-vinyl acetate (hereinafter, referred to as “vinyl chloride-vinyl acetate copolymer”) is used. Examples of vinyl chloride-vinyl acetate copolymers include:
Vinyl chloride-vinyl acetate-vinyl alcohol, vinyl chloride-vinyl acetate-maleic anhydride, vinyl chloride-vinyl acetate-vinyl alcohol-maleic anhydride, vinyl chloride-vinyl acetate-vinyl alcohol-maleic anhydride-maleic anhydride Polymers. Among the vinyl chloride-vinyl acetate copolymers, partially hydrolyzed copolymers are also included.

Vinyl chloride-vinyl acetate, vinyl chloride-maleic anhydride, vinyl chloride-maleic acid, vinyl chloride- (meth) acrylate, vinyl chloride- (meth) hydroxyacryl acrylate, vinyl chloride-vinyl acetate-maleic acid,
Vinyl chloride-vinyl acetate-maleic anhydride, vinyl chloride-vinyl acetate-vinyl alcohol, vinyl chloride-vinyl acetate- (meth) acrylate, vinyl chloride-vinyl acetate- (meth) hydroxyacryl acrylate, vinyl chloride- (meth) acrylate -Maleic acid, vinyl chloride-
(Meth) hydroxyacryl acrylate-maleic acid copolymer is particularly preferred.

At this time, the content of the vinyl chloride component is preferably 50 to 100% by weight, and the vinyl acetate component and / or (meth)
The content of hydroxyacryl acrylate and / or (meth) acrylate (the total amount when both are included) is preferably 0 to 50% by weight, and the content of maleic acid and / or maleic anhydride component ( When both are included, the total amount is 0 to 20% by weight (further 0 to 10% by weight).
% By weight).

The degree of polymerization of vinyl chloride resin is effective over a wide range, and can be determined based on the balance between solubility and addition concentration. The allowable range varies depending on the (co) polymer and solvent used. Cheap. However, this is not the case.

As a method for measuring the degree of polymerization, the vinyl chloride copolymer of the present invention was dissolved by heating in cyclohexanone, and the specific viscosity of the solution was measured at 30 ° C. in accordance with JIS K6721. Is converted to the JIS specific viscosity, and the degree of polymerization is determined.

The vinyl chloride copolymer used in the present invention is polymerized by a polymerization method such as emulsion polymerization, solution polymerization, suspension polymerization, or bulk polymerization. In any method, known techniques such as divisional addition or continuous addition of a molecular weight regulator, a polymerization initiator, and a monomer can be applied as necessary.

Examples of the “resin other than the vinyl chloride resin” include, for example, polyethylene, polypropylene, acrylic resin, methacrylic resin, epoxy resin, polyurethane resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, methacrylic resin, acrylic resin, Addition polymerization type resins such as polyvinylidene chloride and polystyrene, polyaddition type resins, polycondensation type resins, copolymer resins containing two or more of these repeating units, styrene-butadiene copolymer resins, vinylidene chloride- An acrylonitrile copolymer resin and the like, and a high molecular organic semiconductor such as N-vinyl carbazole and the like can be mentioned.

Among them, polyester resin, polycarbonate resin, acrylic resin, epoxy resin, styrene-acryl resin, polyvinyl acetal (for example, polyvinyl butyral), phenol resin, and silicone resin are preferable.

As the carrier-generating substance (CGM), any of inorganic pigments and organic pigments can be used as long as they can generate free carriers by absorbing electromagnetic waves. The following are examples of CGM.

(1) amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, cadmium sulfide, cadmium selenide, cadmium sulfate selenide, mercury sulfide, lead sulfide,
Inorganic pigments such as zinc oxide and amorphous silicon (2) Azo pigments such as monoazo pigments, polyazo pigments, metal complex azo pigments, pyrazolone azo pigments, stilbene azo and thiazole azo pigments (3) Anthraquinone derivatives, anthantrone derivatives, diazo pigments Anthraquinone-based or polycyclic quinone-based pigments such as benzopyrenequinone derivative, pyranthrone derivative, biolanthrone derivative and isoviolanthrone derivative (4) Indigoid-based pigments such as indigo derivative and thioindigo derivative (5) diphenylmethane-based pigment, triphenylmethane pigment (6) quinone imine pigments such as azine pigments, oxazine pigments and thiazine pigments (7) methine pigments such as cyanine pigments and azomethine pigments (8) quinoline pigments 9) Nitro pigments (10) Nitroso pigments (11) Benzoquinone and naphthoquinone pigments (12) Naphthalimide pigments (13) Perylene pigments such as bisbenzimidazole derivatives (14) Fluorenone pigments (15) Squarylium pigments 16) Azurenium compounds (17) Perylene pigments such as perylene anhydride and perylene imide (18) Metal-free phthalocyanine pigments such as α-type, β-type, χ-type and τ-type, and metal phthalocyanine-based pigments such as titanyl phthalocyanine Among them, polycyclic quinone pigments such as anthantrone pigments, dibenzopyrene quinone pigments and pyranthrone pigments, azo pigments, phthalocyanine pigments and the like are particularly preferred.

Hereinafter, preferred azo pigments and polycyclic quinone pigments will be exemplified.

In the photoreceptor as shown in FIG. 1, the thickness of the carrier generation layer is preferably 0.1 to 5 μm, and the thickness of the carrier transport layer is preferably 5 to 50 μm. In the photoreceptor as shown in FIG. 2, the thickness of the carrier generating layer is 1 to 10 μm.
The thickness of the carrier transport layer is preferably 1 to 30 μm. In the photoreceptor as shown in FIG. 3, the thickness of the photosensitive layer is preferably 5 to 30 μm.

The thickness of the undercoat layer or the intermediate layer provided between the photosensitive layer and the conductive substrate as needed is preferably 0.01 to 5 μm.

The thickness of the surface protective layer provided as needed is 0.1 to 5
μm is preferred.

The content of the carrier transporting substance in the carrier transporting layer is preferably from 10 to 200 parts by weight per 100 parts by weight of the binder resin.

In the layer containing the carrier-generating substance, the particulate carrier-generating substance is bound in the binder resin (and may contain a carrier-transporting substance if necessary) and dispersed in the layer in the form of a dye or pigment. Are preferred.

In the case where the photosensitive layer is formed by dispersing a particulate carrier generating substance, the carrier generating substance may be a powder having an average particle size of 2 μm or less, preferably 1 μm or less, more preferably 0.5 μm or less. preferable.

In the carrier transport layer, the carrier transport material preferably has excellent compatibility with the binder material. As a result, the mixing ratio with the binder substance can be made very wide, and the carrier transport layer is uniform and stable, resulting in better sensitivity and charging characteristics. Further, it is possible to obtain a photoreceptor capable of forming a clear image with high sensitivity, and it is possible to obtain an effect of reducing fatigue deterioration, particularly when repeatedly used.

The “layer containing a carrier-generating substance” can be provided by the following method.

(A) A method in which a binder and a solvent are added to a carrier-generating substance and a mixed and dissolved solution is applied.

(B) The carrier-generating substance is transferred to a ball mill, a homomixer,
A method in which fine particles are formed in a dispersion medium with or without a binder using a sand mill, an ultrasonic dispersing machine, an attritor, or the like, and a dispersion obtained by mixing and dispersing the particles, if necessary, is added.

In these methods, when the particles are dispersed under the action of ultrasonic waves, uniform dispersion becomes possible.

At this time, when the “vinyl chloride resin” is insoluble in the solvent in which the “resin other than the vinyl chloride resin” should be dissolved,
After dissolving the “vinyl chloride resin” in another solvent, the respective resin solutions may be mixed. The same effect can be obtained before and after mixing.

When the carrier transporting substance is contained in the layer containing the carrier generating substance, a method of previously dissolving or dispersing the carrier transporting substance in the solution (a) or the dispersion (b), that is, in the carrier generating layer, There is a method of adding a carrier transporting substance to the above. In the type of FIG. 1, a solution containing a carrier transporting substance is applied on the carrier generating layer,
There is a method in which the carrier generating layer is swollen or partially dissolved to diffuse the carrier transporting substance into the carrier generating layer. When this method is employed, it is not necessary to add a carrier transporting substance to the carrier generation layer as described above, but the above two methods may be performed simultaneously.

Further, the carrier transport layer can be formed by applying and drying the above-described carrier transport substance alone or in combination with the binder resin described above, which is dissolved and dispersed.

Further, as the solvent used for forming the photosensitive layer of the present invention,
For example, hexane, benzene, toluene, hydrocarbons such as xylene, methylene chloride, 1,2-dichloroethane, sym-tetrachloroethane, cis-1,2-dichloroethylene, 1,1,2-trichloroethane, 1,1, Halogenated hydrocarbons such as 1-trichloroethane, chloroform, bromoform and chlorobenzene, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, methanol, ethanol, propanol, butanol, cyclohexanol and pectanol; Alcohols such as ethylene glycol, methyl cellosolve, ethyl cellosolve and cellosolve acetate and derivatives thereof. Ethers such as tetrahydrofuran, 1,4-dioxane, furan, furfural, etc., nitrogen compounds such as acetals, pyridine, amines and amides, as well as fatty acids and phenols, sulfur and phosphorus compounds such as carbon disulfide and triethyl phosphate, etc. Any solvent may be used as a single solvent or various mixed solvents containing these as a main component.

Further, any of the above-mentioned solvents can be used as the solvent for the “vinyl chloride resin”. Particularly, ketones (acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, methyl isoamyl ketone, methyl N-amyl ketone, Cyclohexanone, isophorone, etc.), aromatics (benzene, toluene, xylene, etc.) and esters (ethyl acetate, butyl acetate, isobutyl acetate, cellosolve, etc.), and cyclic ethers (THF, etc.) alone or a mixture thereof. preferable.

The photosensitive layer (layer containing a carrier-generating substance, carrier transporting layer), undercoat layer, intermediate layer, protective layer and the like can be provided by, for example, blade coating, dip coating, spray coating, roll coating, spiral coating, or the like. .

Carrier transport materials used in the present invention include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds , Pyrazoline derivatives, oxazolone derivatives, benzothiazole derivatives,
Benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives,
Aminostilbene derivatives, triarylamine derivatives,
Phenylenediamine derivative, stilbene derivative, poly-
One or two or more selected from N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene and the like may be used.

Specific examples of such carrier transport materials are disclosed in Japanese Patent Application No.
-298013 and the like. The general formula is shown below.

A styryl compound of the following general formula [IX] or [X] can be used as a carrier transporting substance.

General formula [IX]: (Wherein, in this general formula, R ¹ and R ² represent a substituted or unsubstituted alkyl group or an aryl group, and the substituent is an alkyl group, an alkoxy group,
A substituted amino group, hydroxyl group, halogen atom, or aryl group is used.

Ar ¹ , Ar ² : represents a substituted or unsubstituted aryl group,
As the substituent, an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, or an aryl group is used.

R ³ and R ⁴ each represent a substituted or unsubstituted aryl group or a hydrogen atom. As the substituent, an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, or an aryl group is used. ) General formula [X]: (Wherein, in this general formula, R ⁵ : substituted or unsubstituted aryl group, R ⁶ : hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, alkoxy group, amino group, substituted amino group, hydroxyl group, R ⁷ : Represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group.) The following general formula [XI]
The hydrazone compound of [XII], [XIIa], [XIIb] or [XIII] can also be used.

General formula [XI]: (In the general formula, R ⁸ and R ⁹ each represent a hydrogen atom or a halogen atom, R ¹⁰ and R ¹¹ each represent a substituted or unsubstituted aryl group, and Ar ³ represents a substituted or unsubstituted arylene group.) General formula [XII]: (Wherein, in this general formula, R ^{12 represents a} substituted or unsubstituted aryl group, a substituted or unsubstituted carbazolyl group, or a substituted or unsubstituted heterocyclic group, and R ¹³ , R ¹⁴ and R ¹⁵ : a hydrogen atom , An alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.) General formula [XIIa]: (However, in this general formula, R ¹⁶ : methyl group, ethyl group, 2-hydroxyethyl group or 2-chloroethyl group, R ¹⁷ : methyl group, ethyl group, benzyl group or phenyl group, R ¹⁸ : methyl group, ethyl A benzyl group or a phenyl group.

General formula [XIIb]: (Wherein, in this general formula, R ¹⁹ is a substituted or unsubstituted naphthyl group; R ²⁰ is a substituted or unsubstituted alkyl group, aralkyl group or aryl group; R ²¹ is a hydrogen atom, an alkyl group or an alkoxy group; R ²² And R ²³ represent the same or different groups each consisting of a substituted or unsubstituted alkyl group, aralkyl group or aryl group.) General formula [XIII]: (However, in this general formula, R ²⁴ : a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group, R ²⁵ : a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, Q: a hydrogen atom, a halogen atom, an alkyl group, a substituted amino group, an alkoxy group or a cyano group, and s represents an integer of 0 or 1.) As a carrier transporting substance, the following general formula [XIV]
Can also be used.

General formula [XIV]: (Wherein, in this general formula, l: 0 or 1, R ²⁶ and R ²⁷ : a substituted or unsubstituted aryl group, R ²⁸ : a substituted or unsubstituted aryl group or heterocyclic group, R ²⁹ and R ³⁰ : A hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a substituted or unsubstituted aryl group or aralkyl group (provided that R ²⁹ and R ³⁰ are not both hydrogen atoms, and when 1 is 0, R ²⁹ is not a hydrogen atom.]] Further, an amine derivative represented by the following general formula [XV] can also be used as a carrier transporting substance.

General formula [XV]: (In the general formula, Ar ⁴ and Ar ⁵ each represent a substituted or unsubstituted phenyl group, and a halogen atom, an alkyl group, a nitro group, or an alkoxy group is used as the substituent.

Ar ^{6 represents a} substituted or unsubstituted phenyl group, naphthyl group, anthryl group, fluorenyl group, heterocyclic group, and the substituent is an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, an aryloxy group, an aryl group, an amino group , A nitro group, a piperidino group, a morpholino group, a naphthyl group, an anthryl group and a substituted amino group. However, an acyl group, an alkyl group, an aryl group, or an aralkyl group is used as a substituent of the substituted amino group. Further, compounds of the following general formula [XVI] can also be used as a carrier transporting substance.

General formula [XVI]: (Wherein, in this general formula, Ar ⁷ represents a substituted or unsubstituted arylene group, R ³¹ , R ³² , R ³³ and R ³⁴ : a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or Represents a substituted or unsubstituted aralkyl group.) Further, a compound represented by the following general formula [XVII] can also be used as a carrier transporting substance.

General formula [XVII]: (In this general formula, R ³⁵ , R ³⁶ , R ³⁷ and R ³⁸ each represent a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, a benzyl group or an aralkyl group, ³⁹ and R ⁴⁰ are each a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms, a cycloalkyl group, an alkenyl group, a cycloalkenyl group,
An aryl group or an aralkyl group (provided that R ³⁹ and R ⁴⁰ may together form a saturated or unsaturated hydrocarbon ring having 3 to 10 carbon atoms), R ⁴¹ , R ⁴² , R ⁴³ and R ⁴⁴ is a hydrogen atom, a halogen atom, a hydroxyl group, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, an aralkyl group, an alkoxy group, an amino group, an alkylamino group, or an arylamino group, respectively. . An antioxidant can be contained in the carrier transport layer, the carrier generation layer and the photosensitive layer. As a result, the influence of ozone generated by discharge can be suppressed, and an increase in the residual potential and a decrease in the charged potential during repeated use can be prevented.

Examples of the antioxidant include hindered phenol, hindered amine, paraphenylenediamine, arylalkane, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, organic phosphorus compounds and the like.

Specific examples of these compounds include Japanese Patent Application No. 61-162866.
Nos. 61-188975, 61-195878, 61-157644
Nos. 61-195879, 61-162867, 61-204469
Nos. 61-217493, 61-217492 and 61-221541
There is a description in the issue.

A high molecular organic semiconductor may be contained in the photosensitive layer. Among these polymer organic semiconductors, poly-N-vinylcarbazole or a derivative thereof has a large effect and is preferably used. Such a poly-N-vinyl carbazole derivative is one in which all or a part of the carbazole ring in the repeating unit is substituted with various substituents, for example, an alkyl group, a nitro group, an amino group, a hydroxy group or a halogen atom. .

In addition, at least one kind of electron accepting substance can be contained in the photosensitive layer for the purpose of improving sensitivity, reducing residual potential, or reducing fatigue during repeated use.

Examples of the electron accepting substance usable in the photoreceptor of the present invention include succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, and 3-nitrophthalic anhydride. , 4-nitrophthalic anhydride, pyromellitic anhydride, melitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, 1,3,5-trinitrobenzene, paranitrobenzonitrile , Picryl chloride, quinone chlorimide,
Chloranil, bromanyl, 2-methylnaphthoquinone, dichlorodicyanoparabenzoquinone, anthraquinone, dinitroanthraquinone, trinitrofluorenone, 9-
Fluorenylidene- [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene- [dicyanomethylenemalonodinitrile], picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid Acid, 5-nitrosalicylic acid,
Examples thereof include one or more of 3,5-dinitrosalicylic acid, phthalic acid, melitic acid, and other compounds having a high electron affinity. Of these, fluorenone,
A quinone derivative or a benzene derivative having an electron-withdrawing substituent such as Cl, CN, and NO ₂ is particularly preferable.

Further, a silicone oil or a fluorine-based surfactant may be present as a surface modifier. Further, an ammonium compound may be contained as a durability improver.

Further, an ultraviolet absorber may be used. As preferred ultraviolet absorbers, nitrogen-containing compounds such as benzoic acid, stilbene compounds and derivatives thereof, triazole compounds, imidazole compounds, triazine compounds, coumarin compounds, oxadiazole compounds, thiazole compounds and derivatives thereof are used.

For the carrier transport layer, the various binder resins described above can be used.

For the undercoat layer or intermediate layer provided as necessary, for example, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, casein, N-alkoxymethylated nylon, starch, etc. are used in addition to the binder resin.

As a binder for the protective layer provided as needed, a transparent resin having a volume resistance of 10 ⁸ Ω · cm or more, preferably 10 ¹⁰ Ω · cm or more, more preferably 10 ¹³ Ω · cm or more is used. The binder may be a resin that is cured by light or heat. Examples of the resin that is cured by light or heat include a thermosetting acrylic resin, a silicone resin,
There are epoxy resins, urethane resins, urea resins, polyester resins, alkyd resins, melamine resins, photocurable cinnamate resins and the like or copolymers or condensation resins thereof, and other light or thermosetting resins used in electrophotographic materials. Are all used. If necessary, the protective layer may contain a thermoplastic resin in an amount of less than 50% by weight for the purpose of improving workability and physical properties (preventing cracks, imparting flexibility, etc.). As such a thermoplastic resin, for example, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin,
Vinyl acetate resin, epoxy resin, polycarbonate resin, silicone resin or copolymer resin thereof, for example, vinyl chloride-vinyl acetate-maleic anhydride resin, poly-N-
All of high molecular organic semiconductors such as vinyl carbazole and other thermoplastic resins used for electrophotographic materials are used.

The conductive substrate is made of a metal, a metal drum, a conductive polymer, a conductive compound such as indium oxide, or a conductive thin layer made of a metal such as aluminum, palladium, gold, etc. What is provided on a substrate such as a film is used.

E. Examples Hereinafter, examples of the present invention will be described, but the embodiments of the present invention are not limited thereto.

[Experiment I]

Manufacture of photoreceptor Vinyl chloride-vinyl acetate-maleic acid copolymer "S-LEC MF-10" on an aluminum substrate with an outer diameter of 80 mm
An intermediate layer having a thickness of about 0.1 μm (made by Sekisui Chemical Co., Ltd.) was provided.

Next, the CGM shown in FIGS. 5 (A), (B) and (C)
(I) 100 parts by weight were pulverized in a ball mill for 24 hours, and a predetermined amount of a “binder resin other than a vinyl chloride resin” shown in FIGS. 5 (A), (B) and (C) was added thereto in a predetermined amount of 1,2. A solution dissolved in 4170 parts by weight of dichloroethane was added, and the mixture was further dispersed in a ball mill for 24 hours. A predetermined amount of a solution obtained by dissolving the “vinyl chloride resin” shown in FIG. 5 in a predetermined solvent is mixed into the obtained dispersion, and the obtained liquid is dip-coated on the intermediate layer and dried sufficiently. Thus, a CGL having a thickness of 1 μm was formed. The content of the “vinyl chloride resin” is expressed as a solid content.

Next, 75 parts by weight of the following CTM (I) and 100 parts by weight of polycarbonate "Iupilon Z-200" (manufactured by Mitsubishi Gas Chemical Industry Co., Ltd.) were dissolved in 625 parts by weight of 1,2-dichloroethane, and the obtained solution was subjected to the above-mentioned method. Dip coating on carrier generation layer, temperature 80
After drying at ℃ for 1 hour, a CTL having a thickness of 20 μm was formed.

"Resins other than vinyl chloride resins" Polycarbonate resin: "PANLITE L-1250" (manufactured by Teijin Chemicals Ltd.) Polyester resin: "Byron 200" (manufactured by Toyobo Co., Ltd.) Acrylic resin: "Acripet # 011" (Mitsubishi Rayon Polyvinyl butyral resin: Eslec BL-S (Sekisui Chemical Co., Ltd.) Epoxy resin: Epicoat 1001 (Yuka Shell Epoxy Co., Ltd.) Vinyl chloride resin Vinyl chloride resin: Denka Vinyl SS-70 ”(Manufactured by Denki Kagaku Kogyo) CGM (I) 4,10-dibromoanthanthrone In this way, the respective photoconductors shown in FIGS. 5A to 5C were prepared by the common manufacturing procedure.

Evaluation of photoreceptor characteristics For each electrophotographic photoreceptor obtained as described above, a voltage of +6 KV was applied to the band electrode using an electrostatic charging tester "EPA-8100" (manufactured by Kawaguchi Electric Manufacturing Co., Ltd.). The photosensitive layer was charged by corona discharge for 2 seconds. Thereafter, the photosensitive layer is left for 5 seconds (the potential at this time is referred to as an initial potential), and then irradiated with light from a halogen lamp in a state where the light intensity on the surface of the photosensitive layer becomes 2 lux, and the initial potential is changed from −600 V to −100 V. Exposure required to attenuate to ▲ E ⁶⁰⁰ ₁₀₀ ▼ (lux · sec)
Was measured.

Further, Sλ was measured at a wavelength of λ = 540 nm using a spectroscope MC-20L (manufactured by Ritsu Applied Optics). Where Sλ is
When light of a specific wavelength λ is irradiated at 0.5 μW / cm ² , V ₀ =
This is the amount of potential decay per unit energy while attenuating from −800 V to V = −100 V. In FIG. 5, the relative values when the value of Sλ for the photoconductor of each comparative example is 1.00. That is, the photoconductors IA and IB1-I
-B11, I-C1 to I-C6, the S
The relative value when the value of λ is 1.00, the relative value when the value of Sλ of the photoreceptor Id is 1.00 for the photoreceptor ID, and the relative value when the value of Sλ of the photoreceptor IE is 1.00. The value of Sλ
The relative value when the value of 1.00 is set, the value of Sλ of the photoreceptor If is set to 1.00 for the photoreceptor IF, and the value of Sλ of the photoreceptor Ig is set for the photoreceptor Ig. The relative values when the photoreceptor is set to 1.00 and the relative values of the photoreceptors I-X1, X2, Y, and Z are expressed as relative values when the value of the photoreceptor 1a is set to 0.

Further U-Bix 1550 MR attached to (manufactured by Konica Corp.) modified machine, black paper potential V _b, blank potential V _w, each variation [Delta] V _b after copying the initial value and 10,000 of residual potential V _r, [Delta] V _w and ΔV _r were measured. That is, ΔV _b = | V _b after copying 10,000 times | − | V _b initial value |, and the other cases are the same.

Note that the black paper potential here refers to the surface potential of the photoconductor when the above-described copying cycle is performed on a black paper original having a reflection density of 1.3, and the blank potential indicates the potential of the photoconductor when a white paper is used as the original. Represents the surface potential.

 FIG. 5 shows the results of these measurements.

(Experiment II)

 An intermediate layer was formed in the same manner as in Experiment I.

Next, 100 parts by weight of CGM (II) shown in FIG. 6 was added to a solution in which a predetermined amount of a binder resin other than the vinyl chloride resin shown in FIG. 6 was dissolved in 10500 parts by weight of 1,2-dichloroethane. And dispersed with a sand grinder for 8 hours. A solution obtained by dissolving a solution of “vinyl chloride resin” shown in FIG. 6 in a predetermined solvent in this dispersion and mixing it in a predetermined amount (represented by a solid component in the figure) is mixed with the intermediate layer. The resultant was applied by dip coating to form a 0.4 μm thick CGL.

Next, in Experiment I, CTM (I) was changed to the following CTM (II), and the other conditions were the same to form CTLs having a thickness of 20 μm.

Thus, the photoconductors II-A to II-D of the experimental example and the photoconductor II-a of the comparative example were prepared.

The same measurement as in Experiment I was performed on each of these electrophotographic photosensitive members. However, for Sλ, the value of II-a is 1.00.
And expressed as a relative value. The results are as shown in FIG.

[Experiment III] An intermediate layer was formed in the same manner as in Experiment I.

Next, to 100 parts by weight of CVM (III) shown in FIG. 6, a solution obtained by dissolving a predetermined amount of a “binder resin other than a vinyl chloride resin” shown in FIG. 6 in 6200 parts by weight of methyl ethyl ketone was added. Disperse with a grinder for 5 hours.
A solution obtained by dissolving the “vinyl chloride resin” in a predetermined solvent shown in FIG. 6 in the obtained dispersion was mixed, and the liquid containing a predetermined amount of the “vinyl chloride resin” as a solid component was added to the dispersion. The intermediate layer was applied by dip coating and dried sufficiently to form a 0.4 μm thick CGL.

Next, in Experiment I, CTM (I) was replaced with CTM (III)
The CTL having a thickness of 20 μm was formed in the same manner.

The electrophotographic photoreceptor III of the example thus prepared
-A, III-B, and Photoconductors III-a and III-b of Comparative Example were measured in the same manner as in Experiment I. The results are as shown in FIG. However, for Sλ, photoconductor III-A
Indicates the value when the value of Sλ of the photoconductor III-a is 1.00, and indicates the value of S of the photoconductor III-b for the photoconductor III-B.
The values when λ is 1.00 are shown.

CGM (III) τ-type metal-free phthalocyanine [Experiment IV] An intermediate layer was formed in the same manner as in Experiment I.

Next, in the same manner as in Experiment III, except that CGM (III) in Experiment III was changed to CGM (IV),
A carrier transport layer was sequentially formed by coating.

The electrophotographic photoreceptor IV-
A, IV-B, and photoconductors IV-a and IV-b of Comparative Examples
The same measurement as in Experiment I was performed. However, for Sλ,
For the photoconductor IV-A, the value of Sλ of the photoconductor IV-a is set to 1.00.
Is expressed as a relative value, and for the photoconductor IV-B,
The value was expressed as a relative value when the value of Sλ of the photoconductor IV-b was 1.00. The results are as shown in FIG.

CGM (IV) X-type metal-free phthalocyanine [Experiment V] The same intermediate layer as in Experiment I was provided.

Next, 75 parts by weight of the CTM (II) and 100 parts by weight of polycarbonate "PANLITE K-1300" (manufactured by Teijin Chemicals Ltd.) were dissolved in 760 parts by weight of 1,2-dichloroethane, and the resulting solution was mixed with the intermediate solution. The layer was applied by dip coating and dried at a temperature of 80 ° C. for 1 hour to form a 20 μm thick CTL.

Next, 50 parts by weight of CGM (I) shown in FIG. 7 was ground by a ball mill for 24 hours, and a predetermined amount of “binder resin other than vinyl chloride resin” shown in FIG. 7 was added in a predetermined amount of 1,2-dichloroethane. A solution dissolved in 1750 parts by weight was added, and the mixture was further dispersed by a ball mill for 24 hours. To this dispersion, 75 parts by weight of CTM (II) was added, and 750 parts by weight of monochlorobenzene and a solution of “vinyl chloride resin” shown in FIG. (Represented by components) to obtain a coating solution. This coating solution was spray-coated on the carrier transport layer to obtain a carrier generating layer having a thickness of 5 μm.

The electrophotographic photosensitive member V-
A, the same measurement as in Experiment I was performed on the photoconductor Va of the comparative example. However, regarding the value of Sλ, the photoconductor VA
Is expressed as a relative value when the value of Sλ of the photoconductor Va is 1.00. The results are as shown in FIG.

(Experiment VI)

 First, an intermediate layer similar to that of Experiment I was formed.

Next, 50 parts by weight of CGM (II) shown in FIG. 7 is added to the predetermined “binder resin other than the vinyl chloride resin” shown in FIG.
Was dissolved in a predetermined amount of 1,750 parts by weight of 1,2-dichloroethane, and the mixture was dispersed with a sand grinder for 8 hours. To this dispersion, 75 parts by weight of the following CTM (III) was added, and a predetermined amount of a solution obtained by dissolving "vinyl chloride resin" in a predetermined solvent shown in FIG. 7 (represented as a solid component in the figure). In addition, a coating solution was prepared. This coating solution was dip-coated on the intermediate layer to obtain a photosensitive layer having a thickness of 15 μm.

The electrophotographic photosensitive member VI-
A, the same measurement as in Experiment I was performed on the photoconductor VI-a of the comparative example. However, the value of Sλ of the photoconductor VI-A of the example was represented by a relative value when the value of Sλ of the photoconductor VI-a was 1.00. The results are as shown in FIG.

The resins shown in FIGS. 6 and 7 are the same as the resins shown in FIG.

As is clear from the above experimental results, it is understood that the photoreceptor of the example has a good photosensitivity, and particularly has an excellent blank paper potential _VL .

(Experiment VII)

The following experiment was conducted using the photoreceptor formulation described in the section of Experiment I.

That is, in the same manner as described in Experiment I, 50 parts by weight of a polycarbonate resin, a vinyl chloride resin, and CGM
(I) An electrophotographic photosensitive member having a carrier generation layer containing 100 parts by weight was prepared.

However, at this time, the content of the vinyl chloride resin with respect to the polycarbonate resin (see FIG. 8) (converted value with respect to 100 parts by weight of the polycarbonate resin) was variously changed. In addition, for the intermediate layer and the carrier transport layer, Experiment I
The same as above. However, in the comparative example, the amount of the polycarbonate resin itself was increased by the “content” shown on the horizontal axis in FIG.

Sλ was measured for each photoreceptor thus prepared. However, the value of Sλ was a relative value when the value of Sλ was 1.00 when the content ratio of the vinyl chloride resin was 0 parts by weight.

 The results are as shown in FIG.

According to this result, it is considered that the higher the average degree of polymerization, the larger the addition of a small amount.

The resin used for the intermediate layer is a vinyl chloride-vinyl acetate-maleic acid resin.
Alternatively, even without the intermediate layer, the above-described effect was obtained.

[Brief description of the drawings]

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are cross-sectional views of each example of the photoconductor. FIG. 5 (A), FIG. 5 (B), FIG. 5 (C), FIG.
FIG. 7 is a graph showing the relationship between the configuration and prescription of the electrophotographic photosensitive member and the electrophotographic characteristics. FIG. 8 is a graph showing the relationship between the amount of potential decay per unit energy during light irradiation and the amount of vinyl chloride resin added to the carrier generation layer. In the reference numerals shown in the drawings, I: conductive support 2: charge generation layer (CGL) 3: charge transport layer (CTL) 4A, 4B, 4D: photosensitive layer 5: surface (protection) layer (OCL).

Continuation of the front page (72) Inventor Kiyoshi Tamaki 2970, Ishikawa-cho, Hachioji-shi, Tokyo Inside Konica Corporation (56) References JP-A-59-84247 (JP, A) JP-A-57-654 (JP, A)

Claims (1)

(57) [Claims] 1. Photosensitivity is increased by incorporating a carrier generating substance, a resin other than a vinyl chloride resin, and 0.2 to 30 parts by weight of a vinyl chloride resin with respect to 100 parts by weight of the resin other than the vinyl chloride resin. A photoreceptor, comprising: