JPH11160903A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a photoreceptor being excellent in conductivity and little in a residual potential and capable of forming an image without defects in the image quality such as black spots and white spots by providing an intermediate layer containing specified charge transfer polymer particles between a conductive base body and a photosensitive layer. SOLUTION: In an electrophotographic photoreceptor provided with an intermediate layer and a photosensitive layer on a conductive base body, the intermediate layer contains charge transfer polymer particles and the charge transfer polymer particles contains charge transfer polymer compds. expressed by formulae I to VI. In formulae I to VI, at least either of A or B is a bivalent group and the other is a bivalent aliphatic hydrocarbon group or an aromatic hydrocarbon group which may be substd., A' is a univalent group and p is an integer of 5 to 5000. The intermediate layer is preferably a charge injection layer or a charge transfer polymer particle layer in which the charge transfer polymer particles are dispersed in an electric insulating resin. Since the intermediate layer contains the charge transfer polymer particles, the production of defects in the image quality can be suppressed without damaging the charge transfer property.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a conductive material on a conductive substrate.
The present invention relates to an electrophotographic photoconductor provided with an intermediate layer containing charge transporting polymer particles and a photosensitive layer.

[0002]

2. Description of the Related Art The repetition stability required for an electrophotographic photoreceptor is becoming severer year by year. In order to suppress the occurrence of image quality defects such as black spots and white spots, the distance between a conductive substrate and a photosensitive layer is reduced. Providing an intermediate layer is under consideration. However, when an insulating resin is provided on a conductive substrate, the residual potential increases, and the resin is not practically usable. It has also been considered to disperse a conductive material or conductive particles in the intermediate layer to lower the residual potential, but it is not possible to completely suppress the reduction in chargeability and the occurrence of image quality defects. Have a point. It has been studied to use a resin such as nylon or polyvinyl alcohol having hygroscopicity as an intermediate layer to lower the residual potential by ionic conductivity (JP-A-2-47666, etc.). Has a problem such as an increase in It has also been proposed to reduce the residual potential by using a thin film of a conductive organic polymer such as polyaniline, polypyrrole, or polythiophene as an intermediate layer (Japanese Patent Application Laid-Open No. 3-41462). Are conductive, have no ability to block injected charges, and have problems such as the inability to completely suppress the occurrence of image quality defects.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances in the prior art, and has no image defects such as black spots and white spots, and has excellent chargeability. An object of the present invention is to provide an electrophotographic photosensitive member having a small residual potential.

[0004]

The above object can be attained by incorporating charge transporting polymer particles into the intermediate layer. That is, the electrophotographic photoreceptor of the present invention is:
At least an intermediate layer and a photosensitive layer are provided on a conductive substrate, wherein the intermediate layer contains charge transporting polymer particles. In the present invention, the intermediate layer is preferably a charge injection layer, and more preferably a charge transporting polymer particle layer in which charge transporting polymer particles are dispersed in an electrically insulating resin. According to the invention, since the intermediate layer contains polymer particles having a charge transporting property, it is possible to suppress the occurrence of image quality defects without impairing the charge transporting performance.

In the present invention, the charge transporting polymer particles preferably contain a charge transporting polymer compound represented by the following general formulas (I) to (VI).

[0006]

1 to 3 are schematic cross-sectional views of a specific example of an electrophotographic photosensitive member according to the present invention.
Shows a single-layer type in which an intermediate layer 4 containing the charge-transporting polymer particles 1 is provided on a conductive support 2 and a photosensitive layer 3 is provided thereon. FIG. 2 shows a laminated type in which an intermediate layer 4 containing the charge transporting polymer particles 1 is provided on the substrate 2, and a charge generating layer 5 and a charge transporting layer 6 are sequentially provided on the intermediate layer 4. FIG. 2 shows a laminate type in which an intermediate layer 4 containing the charge transporting polymer particles 1 is provided on the substrate 2 and a charge transport layer 6 and a charge generation layer 5 are sequentially provided thereon.

Hereinafter, each layer constituting the electrophotographic photosensitive member of the present invention will be described in detail. As the conductive support,
It can be opaque or substantially transparent, metals such as aluminum, nickel, chromium, stainless steel, and aluminum, titanium, nickel, chromium, stainless steel, gold, vanadium, tin oxide, indium oxide, I
Examples of the material include a plastic film and glass provided with a thin film such as TO, and paper, a plastic film and glass coated or impregnated with a conductivity-imparting agent. These conductive supports can be used as drums, sheets, plates, and other suitable shapes.
It is not limited to these. Further, if necessary, the surface of the conductive support can be subjected to various treatments within a range that does not affect the image quality. For example, oxidation treatment of the surface,
Chemical treatment, coloring treatment, or irregular reflection treatment such as graining can be performed.

Next, the intermediate layer provided on the conductive support will be described. The intermediate layer contains the charge transporting polymer particles, and the charge transporting polymer particles are produced by using a raw material having a charge transporting group introduced therein and utilizing a known method for producing polymer particles. be able to. Specific examples of the method for producing the polymer particles include a pulverization method, an emulsion polymerization method, a suspension polymerization method, a step polymerization method, a dispersion polymerization method, an emulsion dispersion method, and the like, but are not limited thereto. Absent. The pulverization method is a method of producing polymer particles by pulverizing a polymer lump or a powder having a large particle diameter with mechanical force. The emulsification dispersion method is a method of producing polymer particles by dissolving a polymer in an organic solvent or melting by heating, emulsifying in a dispersion medium, and removing the solvent and, if necessary, the dispersion medium.
According to this method, the charge transporting polymer particles can be obtained in a state of being dispersed in the dispersion medium or in a powder state by removing the dispersion medium.

For example, a charge-transporting polymer compound is dissolved in an oily medium, which is emulsified and dispersed in an aqueous medium, and then the organic solvent is removed to form charge-transporting polymer particles having an average particle size of 0.01 to 10 μm. Obtainable. The obtained fine particles may be filtered and used as a single particle after performing a washing operation, or may be used in a dispersed solution state after performing solvent replacement. Specific organic solvents that dissolve the charge transporting polymer compound include, for example, acetates such as ethyl acetate, halogenated hydrocarbons such as methylene chloride, aromatic hydrocarbons such as toluene and xylene, and methyl isobutyl ketone. Those which are not miscible with the aqueous medium, such as ketones such as In order to emulsify and disperse the oil phase containing the charge transporting polymer compound, a protective colloid may be previously contained in the aqueous medium. As the protective colloid, a water-soluble polymer can be used, and can be appropriately selected from among known anionic polymers, nonionic polymers, and amphoteric polymers, and include polyvinyl alcohol, gelatin, and cellulose-based water-soluble polymers. It is particularly preferred to include Further, the aqueous medium may contain a surfactant. As the surfactant, a surfactant that does not cause precipitation or aggregation by acting on the protective colloid described above can be appropriately selected and used from anionic or nonionic surfactants. Specific examples include sodium alkylbenzene sulfonate (eg, sodium lauryl sulfate), dioctyl sodium sulfosuccinate, polyalkylene glycol (eg, polyoxyethylene nonyl phenyl ether), and the like. The amount can be appropriately adjusted and used to obtain a desired particle size, but is preferably 0.01 to 40% by weight, more preferably 0.1 to 40% by weight.
-20% by weight.

[0010] The charge transporting polymer particles may be crosslinked and cured. By cross-linking the charge transporting polymer particles, it becomes difficult to dissolve in the solvent, and the range of selection of the coating solvent is widened, so that the range of selection of the binder resin is widened and the range of the selection of the coating solvent of the upper layer is also widened. By expanding, it is possible to design a higher performance electrophotographic photosensitive member.

The crosslinked charge transporting polymer particles can be prepared by the method described below. That is, a compound having a charge transporting property and a compound having a charge transporting property, or a compound coating the compound, is dissolved or dispersed in a specific organic solvent to prepare an oily mixture, and this oily mixture is If desired, charge-transporting polymer particles having an average particle size in the range of 0.01 to 10 μm can be obtained by emulsifying and dispersing in an aqueous medium containing a reactive component and removing the organic solvent. Here, the compound having a charge transporting property may be either a hole transporting property or an electron transporting property. The compound having a charge transporting property may be a high molecular compound having a reactive group or a low molecular compound having a reactive group. The obtained fine particles may be filtered and used as a single particle after performing a washing operation, or may be used in a dispersed solution state after performing solvent replacement.

In the present invention, a known charge transporting polymer compound can be used as the polymer compound used for the charge transporting polymer particles. For example, a polymer compound having a charge-transporting group in its side chain such as polyvinylcarbazole, or a polymer having a charge-transporting group in its main chain as disclosed in JP-A-5-232727. Compounds and polysilanes can be mentioned. As the charge transporting polymer particles, a charge transporting polymer compound can be used alone or in combination of two or more. When two or more kinds are mixed, they may be formed into particles in a mixed state or may be mixed as individual particles. In addition, the charge transporting polymer particles may include a charge transporting low molecular compound or a charge transporting oligomer.

When the charge-transporting polymer particles contain a polymer compound having a structure represented by the following general formulas (I) to (VI), they have high charge-transporting ability and excellent mechanical properties. Is particularly preferred.

[0014]

Embedded image [Wherein at least one of A and B represents a divalent group represented by the following general formulas (1) to (7);
The other represents a divalent aliphatic hydrocarbon group or an aromatic hydrocarbon group which may be substituted, and A ′ represents a monovalent group represented by the following formulas (8) to (16); Represents an integer of 5 to 5000, preferably 20 to 400.

[0015]

Embedded image

Embedded image In the formula, R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a substituted amino group, a halogen atom,
Or a substituted or unsubstituted aryl group, and X is
Substituted or unsubstituted 2 represented by the following formulas (a) to (f)
Represents a valent aromatic ring-containing group,

Embedded image (Wherein, R _{9 to} R ₁₁ each represent a phenyl group, a substituted or unsubstituted aralkyl group or a halogen atom;
a and b each represent an integer of 0 or 1;
Represents a group selected from the following formulas (g) to (p).

[0016]

Embedded image (Where c represents an integer of 1 to 10, d represents an integer of 1 to 3), and T represents an optionally branched alkylene group having 1 to 10 carbon atoms, an arylene group, or an alkylenecarbonyl group. , An arylenecarbonyl group, an alkyleneimino group, an aryleneimino group, an alkyleneoxy group or an aryleneoxy group, and k and l are each 0
Or an integer selected from 1. Also, R ₅ and R
₆ represents an alkyl group, an aryl group, a halogen atom, a nitro group, an acyl group or a cyano group, X ′ represents an oxygen atom,

Embedded image Wherein R ₁₂ and R ₁₃ each represent an alkyl group or an aryl group. Y represents> C = X ′, an oxygen atom, a sulfur atom, —SO ₂ — or —NR ₁₄ — (provided that X ′ has the same meaning as above, and R ₁₄ represents a hydrogen atom, an alkyl group, an aryl group or an acyl group), and m
And n each represent an integer of 0 to 2. ｝

Embedded image

Embedded image (Wherein, R _{1 to} R ₆ , X, T, X ′, Y, 1, k, m, and n have the same meanings as described above, provided that when k = 0, X is bonded to a hydrogen atom. To form a terminal group.
_{1 'to} R _4' each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a substituted amino group, a halogen atom or a substituted or unsubstituted aryl group,, R ₇ and R ₈ are each an alkyl group, a halogen Represents an atom, a nitro group, an acyl group or a cyano group, Z represents an oxygen atom or ＣC (CN) ₂ , and Y ′ represents —COO (CH ₂ )
_t - or _{-C 6 H 4 -COO (CH 2} ) t - (. However, t is 1 to an integer of 6) in Table 1 to Table 5, in the general formula (I) ~ (VI) The specific example of the high molecular compound shown is shown.

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

[0019]

[Table 4]

[0020]

[Table 5]

As the low-molecular compound having a reactive group having a charge transporting property, a known compound can be used. For example, the following compounds can be given as low-molecular compounds having a reactive group having a hole transporting property.

Embedded image

Examples of the low molecular weight compound having a reactive group having an electron transporting property include the following.

[0023]

Embedded image

Examples of the compound which reacts with or coats a compound having a charge transporting property which is a component used for preparing crosslinked charge transporting polymer particles include, for example, a silyl isocyanate compound and a polyvalent isocyanate. Examples include compounds, silane coupling agents, titanate coupling agents, and the like. The content of these compounds is set in the range of preferably 0.1 to 90% by weight, more preferably 1 to 60% by weight, based on the compound having the charge transporting property. Specifically, the following are exemplified.

Examples of the silyl isocyanate compound include silyl isocyanate derivatives represented by the following formulas (VII), (VIII) and (IX) and condensates thereof. (R) _e (R ′) _f (R ″) _g Si (NCO) _4-efg (VII) (RO) _e (R′O) _f (R ″ O) _g Si (NCO) _4-efg (VIII) (R) _h (R′O) _i Si (NCO) _j (IX) (wherein R, R ′ and R ″ are each an alkyl group,
Represents an aryl group or an alkenyl group, e, f and g
Is an integer of 0 to 3, respectively, and e + f + g ≦
3, h, i and j are each an integer of 1 or 2, and satisfy h + i + j = 4. As specific examples of the silyl isocyanate compound, for example, (CH ₃ ) ₃ SiNCO, (C ₂ H ₅ ) ₃ SiNC
O, (C ₃ H ₇ ) ₃ SiNCO, (C ₄ H ₉ ) ₃ SiN
CO, (CH ₃ ) (C ₂ H ₅ ) (C ₃ H ₇ ) SiNC
O, (CH ₃ ) (C ₂ H ₅ ) ₂ SiNCO, (CH ₃ )
₂ (C ₂ H ₅ ) SiNCO, (CH ₃ ) ₃ SiNCO,
(CH ₃ ) ₂ Si (NCO) ₂ , (C ₂ H ₅ ) ₂ Si
(NCO) ₂ , (C ₃ H ₇ ) ₂ Si (NCO) ₂ , (C
₄ H ₉ ) ₂ Si (NCO) ₂ , CH ₃ Si (NC
O) ₃ , C ₂ H ₅ Si (NCO) ₃ , C ₃ H ₇ Si (N
CO) ₃ , C ₄ H ₉ Si (NCO) ₃ , CH ₂ ＣＨCHS
i (NCO) ₃ , CH ₂ ＣC (CH ₃ ) Si (NCO)
₃ , (CH ₃ O) ₃ SiNCO, (C ₂ H ₅ O) ₃ Si
NCO, (C ₃ H ₇ O) ₃ SiNCO, (C ₄ H ₉ O)
₃ SiNCO and the like.

Examples of the polyvalent isocyanate compound include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,6-tolylene diisocyanate, 2,4-tolylene diisocyanate, and naphthalene-isocyanate.
1,4-diisocyanate, diphenylmethane-4,
4'-diisocyanate, 3,3'-dimethoxy-4,
4-biphenyl-diisocyanate, 3,3'-dimethylphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate, trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1 Diisocyanates such as 2,2-diisocyanate, butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,4-diisocyanate, 4,4 ', 4 "-triphenylmethane triisocyanate, toluene −2,4,6
Triisocyanates such as triisocyanate, 4,
4'-dimethyldiphenylmethane-2,2 ', 5,5'
-Tetraisocyanates such as tetraisocyanate,
Isocyanate preforms such as adducts of hexamethylene diisocyanate and trimethylolpropane, adducts of 2,4-tolylenediisocyanate and trimethylolpropane, adducts of xylylenediisocyanate and trimethylolpropane, and adducts of tolylenediisocyanate and hexanetriol. Polymers.

Examples of the silane coupling agent and the titanate coupling agent include the following. That is, vinyltrimethoxysilane, vinyltriethoxysilane, tris- (β-methoxyethoxy) vinylsilane, vinyltriacetoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, β-mercaptoethyltrimethoxysilane, γ-chloropropyltrimethoxysilane, isopropyltristearoyl titanate, isopropyl methacrylisostearoyl titanate, and other known compounds Is raised.

In order to further improve the charge transporting performance, a compound having a charge transporting property can be used as a component that reacts with the charge transporting compound or a component that coats the charge transporting compound. For example, as the compound imparted with the charge transport property, a compound represented by the following general formula (X) can be given.

[0029]

Embedded image [In the formula, Ar _{1 to} Ar ₄ represent a substituted or unsubstituted aryl group, Ar ₅ represents a substituted or unsubstituted arylene group, and s represents 0 or 1. Where Ar ₁
At least one of Ar ₅ to Ar ₅ has the formula: —CH ₂ CH
_2- Y ″ -Si (R ₁₅ ) _3-r (OR ₁₆ ) has a substituent represented by _r . (Where R ₁₅ is a hydrogen atom and has 1 to 1 carbon atoms)
10 represents an alkyl group, a substituted or unsubstituted aryl group, R ₁₆ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a trialkylsilyl group, r represents an integer of 1 to 3, Y ″ represents a divalent group.)]

Table 6 shows specific examples of the above compounds.

[Table 6]

For the purpose of preventing deterioration of the photoreceptor due to ozone or oxidizing gas generated in the electrophotographic apparatus, or light or heat, an antioxidant is contained in the charge transporting polymer particles.
Light stabilizers, heat stabilizers and the like can be added. As the antioxidant, known ones can be used, for example, hindered phenol, hindered amine, paraphenylenediamine, hydroquinone, spirochroman,
Spiroidanone and their derivatives, organic sulfur compounds, organic phosphorus compounds and the like. As a light stabilizer,
Known compounds can be used, for example, benzophenone, benzotriazole, dithiocarbamate, derivatives such as tetramethylpiperidine, and electron-withdrawing compounds and electron-donating compounds that can deactivate a photoexcited state by energy transfer or charge transfer. And the like.

The polarity of the transport charge of the charge transporting polymer particles contained in the intermediate layer may be positive or negative, but is preferably the same as the charge polarity. Further, the charge transporting polymer particles may be capable of transporting charges of both polarities. Further, charge transporting polymer particles capable of transporting only positive charges and charge transporting polymer particles capable of transporting only negative charges may be used in combination.

The content of the charge transporting polymer particles in the intermediate layer is preferably in the range of 1% by weight to 70% by weight. More preferably, it is in the range of 10% by weight to 60% by weight.
When the content is less than 1% by weight, the effect of improving the charge transportability is small, and when the content is more than 70% by weight, a gap is formed between the particles, the adhesion between the particles is insufficient, and the mechanical strength is reduced. When the matrix of the layer containing the charge transporting polymer particles is electrically inactive, the charge is transported by contact between the charge transporting polymer particles, whereby the transport speed can be increased and the residual potential can be reduced. Therefore, when the matrix of the layer containing the charge transporting polymer particles is electrically inactive, the content of the charge transporting polymer particles in the layer is preferably in the range of 20% by weight to 60% by weight.

The particle diameter of the charge transporting polymer particles contained in the intermediate layer is preferably 5 μm or less in terms of volume average particle diameter. More preferably, it is in the range of 0.05 to 2 μm. When the particle diameter is larger than the above range, it becomes difficult to form a uniform film, and the sharpness of an image is deteriorated due to light scattering, diffraction and the like.

Further, since the intermediate layer in the present invention is in a form in which the charge transporting polymer particles are dispersed, light for preventing interference patterns generated in an exposure type electrophotographic apparatus using a coherent light source such as a laser. It can also serve as a scattering layer. Further, the surface roughness of the intermediate layer can be increased by the charge transporting polymer particles. In this case, the particle diameter of the charge transporting polymer particles is most preferably in the range of 0.1 to 1 μm in terms of the secondary particle diameter. Further, diffraction due to a difference in refractive index between the charge transporting polymer particles and the binder resin can also be used.

As the binder resin for the intermediate layer, a known electric insulating resin can be used. For example, polyethylene resin, acrylic resin, methacrylic resin, polyamide resin,
Vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, vinylidene chloride resin, polyvinyl acetal resin,
Vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, water-soluble polyester resin, alcohol-soluble nylon resin, nitrocellulose, casein, gelatin,
Polyglutamic acid, starch, starch acetate, amino starch, polyacrylic acid, resins such as polyacrylamide and their copolymers, or zirconium alkoxide compounds, titanium alkoxide compounds, curable metal organic compounds such as silane coupling agents, They can be used alone or in combination of two or more. Further, if necessary, an electrically inert inorganic filler, an electrically inert organic filler, and the like can be included. Furthermore,
A low molecular charge transporting compound may be contained.

The intermediate layer containing the charge transporting polymer particles comprises:
A coating solution obtained by dispersing the charge transporting polymer particles in a solution containing the binder resin, or a coating solution obtained by dissolving the binder resin in a dispersion of the charge transporting polymer particles is applied. , And dried. At this time, it is necessary to select a solvent that does not dissolve the charge transporting polymer particles as the solvent of the coating solution. As a method for dispersing the charge transporting polymer particles in the solution, a known dispersion method can be used in addition to mixing and stirring. For example, a method using a sand mill, a ball mill, a paint shaker, a homogenizer, and the like, a method using ultrasonic waves, and the like can be used.

The thickness of the intermediate layer is 0.01 to 10 μm.
The range of m is appropriate, preferably in the range of 0.05 to 5 μm. As a coating method, a commonly used method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method can be used.

The intermediate layer formed as described above prevents charge injection from the conductive support into the photosensitive layer during charging of the photosensitive layer, and also integrates the photosensitive layer with the conductive support. Exhibiting an action as an adhesive layer by adhering and holding, or an action of preventing light reflection from the conductive support in some cases.

A photosensitive layer is formed on the intermediate layer. The photosensitive layer may be of a single layer type in which a charge generating substance is dispersed and contained in a resin, or a laminated type of a charge generating layer and a charge transporting layer. It may be. Further, the charge transport layer may have two or more layers. When the photosensitive layer is of a single layer type, it can be prepared by dispersing and applying a charge generating material in a binder resin. The photosensitive layer may contain a charge transporting low molecular weight compound and / or a charge transporting high molecular weight compound. Furthermore, improvement of light sensitivity,
For the purpose of lowering the residual potential, a material having electron affinity can be included. Furthermore, in order to maintain chemical stability, an antioxidant and / or an ultraviolet absorber may be contained.

The compounding ratio (weight ratio) of the charge generating material and the binder resin in the single-layer type photosensitive layer is preferably in the range of 1: 1 to 1: 100. More preferably, it is set in the range of 1: 3 to 1:50. When the compounding ratio of the charge generation material to the binder resin is larger than the above range, dark decay is increased and mechanical properties are deteriorated. If the amount is less than the above range, troubles such as a decrease in photosensitivity and an increase in residual potential occur. The thickness of the photosensitive layer in the single-layer type is generally 1 to 100 μm.
m is appropriate, and is preferably set in the range of 5 to 50 μm. Application methods include blade coating, wire bar coating, spray coating, dip coating, bead coating,
A commonly used method such as an air knife coating method and a curtain coating method can be used.

When the photosensitive layer has a laminated structure, the charge generation layer can be formed by applying a charge generation material by a vacuum evaporation method or by dispersing or dissolving the charge generation material in a binder resin and applying the same. it can. The charge generation layer may contain a charge transporting low molecular weight compound and / or a charge transporting high molecular weight compound. Furthermore,
Antioxidants and / or UV absorbers can be included to maintain chemical stability.

The compounding ratio (weight ratio) of the charge generation material and the binder resin in the charge generation layer is preferably in the range of 10: 1 to 1:10. More preferably, it is set in the range of 3: 1 to 1: 1. When the compounding ratio of the charge generation material to the binder resin is larger than the above range, dark decay is increased and mechanical properties are deteriorated. If the amount is less than the above range, problems such as a decrease in photosensitivity and an increase in residual potential occur. In general, the thickness of the charge generation layer used in the present invention is suitably from 0.05 to 5 μm, and preferably from 0.1 to 2.0 μm. As a coating method, a blade coating method,
Conventional methods such as a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method can be used.

As the charge generating material used for the single-layer type photosensitive layer and the laminated type charge generating layer in the electrophotographic photoreceptor of the present invention, known materials can be used. For example, amorphous selenium, selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and selenium alloys, inorganic photoconductive materials such as zinc oxide, titanium oxide, a-Si, a-SiC, phthalocyanine, squarium Organic pigments and dyes such as, but not limited to, organic pigments, anthrone-based, perylene-based, azo-based, anthraquinone-based, pyrene-based, pyrylium salts, and thiapyrylium salts can be used. Also, these organic pigments and dyes
They can be used alone or in combination of two or more.

The phthalocyanine-based compound has a wavelength of 60 nm, which is the emission wavelength of an LED or a laser diode which is currently used as a light source in a digital electrophotographic apparatus.
Since it has excellent photosensitivity at 0 to 850 nm, it is particularly preferable as the charge generation material of the present invention. Specifically, they are metal-free phthalocyanine and metal phthalocyanine, and the central metals of the metal phthalocyanine include Cu, Ni, Zn, C
o, Fe, V, Si, Al, Sn, Ge, Ti, In,
Examples thereof include Ga, Mg, Pb, and the like, and oxides, hydroxides, halides, alkylates, alkoxylates, and the like of these central metals can also be used. Specific examples include metal-free phthalocyanine, titanyl phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine, dichlorotin phthalocyanine, and the like. Further, those in which the phthalocyanine nucleus of these phthalocyanine compounds contains an arbitrary substituent can also be used. Further, those in which an arbitrary carbon atom in the phthalocyanine nucleus is substituted with a nitrogen atom are also effective. As the form of these phthalocyanine compounds, it is possible to use amorphous or all polymorphic forms. Among these phthalocyanine-based compounds, titanyl phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, and dichlorotin phthalocyanine have particularly excellent photosensitivity and are particularly preferable as charge generation materials.

As the binder resin used in the single-layer type photosensitive layer and the laminated type charge generation layer in the present invention, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal resin, polycarbonate resin, polyester resin, acrylic resin, Polyvinyl chloride resin,
Examples include, but are not limited to, polystyrene resins, polyvinyl acetate resins, vinyl chloride-vinyl acetate copolymers, silicone resins, phenol resins, poly-N-vinyl carbazole resins, and the like. These binder resins may be any of block, random or alternating copolymer. These binder resins can be used alone or in combination of two or more.

As the charge transport layer in the laminated photosensitive layer, known materials used in conventional laminated electrophotographic photosensitive members can be used. For example, benzidine compounds, amine compounds, hydrazone compounds,
Use of hole transporting low molecular weight compounds such as stilbene compounds and carbazole compounds, or electron transporting low molecular weight compounds such as fluorenone compounds, malononitrile compounds and diphenoquinone compounds alone or in combination of two or more Can be. Those can be used as a solid solution film in which molecules are uniformly dispersed in an insulating resin such as polycarbonate, polyarylate, polyester, polysulfone, and polymethyl methacrylate. In addition, a polymer compound having a charge transporting ability by itself can be used. Further, an inorganic substance having a charge transporting ability, such as selenium, amorphous silicon, or amorphous silicon carbide, can also be used. Examples of the charge-transporting polymer compound include polymer compounds having a group having a charge-transporting ability such as polyvinylcarbazole in a side chain;
Examples thereof include a polymer compound having a group having a charge transporting ability in a main chain thereof, and polysilane and the like as disclosed in JP-A-32727 and the like.

Further, as the charge-transporting polymer compound of the charge-transporting layer, charge-transporting polymers represented by the above-mentioned general formulas (I) to (VI) can be used. It is particularly preferable because it has excellent mechanical properties.

The thickness of the charge transport layer in the present invention is from 1 to
It is set to 100 μm, preferably 5 to 50 μm. As a coating method, a commonly used method such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method can be used. In addition, those capable of vapor phase film formation can be directly formed by a vacuum evaporation method or the like.

A protective layer may be further provided on the single-layer type photosensitive layer or the laminated type photosensitive layer composed of the charge generation layer and the charge transport layer, if necessary. This protective layer protects the photosensitive layer from chemical stress such as ozone and oxidizing gas generated from the charging member, ultraviolet light, etc., or mechanical stress caused by contact with the developer, paper, cleaning member, etc. However, it is effective for improving the substantial life of the photosensitive layer. In particular, the effect is remarkable in the case of a layer configuration using a thin charge generation layer as an upper layer.

The protective layer can be formed by including the charge transporting polymer particles in a suitable binder resin. As the binder resin, known resins such as polyamide, polyurethane, polyester, polycarbonate, polystyrene, polyacrylamide, silicone resin, melamine resin, phenol resin, and epoxy resin can be used. The thickness of the protective layer is suitably in the range of 0.5 to 20 μm, and is preferably set in the range of 1 to 10 μm.

When a protective layer is provided, a blocking layer for preventing electric charge from leaking from the protective layer to the photosensitive layer can be provided between the photosensitive layer and the protective layer, if necessary. As the blocking layer, a known layer can be used as in the case of the protective layer.

In the electrophotographic photosensitive member of the present invention, ozone or oxidizing gas generated in the electrophotographic apparatus, or
Antioxidants, light stabilizers, heat stabilizers, and the like can be added to each of the above layers or the uppermost layer for the purpose of preventing the photoreceptor from deteriorating due to light and heat. For example, hindered phenol, hindered amine, paraphenylenediamine, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, organic phosphorus compounds and the like can be used. Known light stabilizers can be used, for example, benzophenone, benzotriazole, dithiocarbamate, derivatives such as tetramethylpiperidine, and electrons that can deactivate the photoexcited state by energy transfer or charge transfer. Examples thereof include an attractive compound and an electron donating compound. Further, insulating particles such as a fluororesin may be dispersed in the outermost surface layer for the purpose of reducing surface wear, improving transferability, improving cleanability, and the like.

The electrophotographic photoreceptor of the present invention may further comprise a diffuse reflection layer and / or a surface protective layer, if desired.

[0055]

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following examples, and those skilled in the art can modify the following examples based on known knowledge of electrophotographic technology.

<Preparation Example of Charge-Transporting Polymer Particles> (Preparation Example 1) As the charge-transporting polymer compound, the polymer compound No. 1 shown in Table 1 was used. 20 g of 1 is 150 g of toluene
Was added as a compound capable of reacting with the charge-transporting polymer compound, and 3.0 g of trimethylolpropanexylidene diisocyanate adduct (Takenate D110N, manufactured by Takeda Pharmaceutical Company Limited) was added to prepare an oily mixed solution. The obtained oily mixture was added to 1.0 kg of a 1.0% aqueous solution of polyvinyl alcohol as an aqueous medium, and 8000 rpm was added.
After emulsifying and dispersing at a rotation speed of 3, the toluene was removed at normal pressure for 3 hours in a thermostat at 60 ° C., washed with distilled water, freeze-dried, and crosslinked with an average particle size of 0.2 μm. 20 g of the obtained charge transporting polymer particles were obtained. When the solubility of the obtained charge transporting polymer particles in an organic solvent was examined, it was confirmed that the particles were insoluble in solvents such as an ester, an amide, a halogen, and a sulfoxide.

(Preparation Example 2) As the charge transporting polymer compound, the polymer compound No. 1 in Preparation Example 1 was used. In place of Polymer Compound No. 1 shown in Table 3, Compound No. 14 shown in Table 6 was used as a compound capable of reacting with the charge transporting polymer compound using 25 g of Compound No. 14. 1, 4.1 g of hexadecylpyridinium chloride monohydrate 1.0% aqueous solution was further used as an aqueous medium.
The same operation was performed to obtain 20 g of crosslinked charge transporting polymer particles having an average particle diameter of 0.3 μm. Similarly, when the solubility of the charge transporting polymer particles in an organic solvent was examined, it was confirmed that the particles were insoluble in solvents such as ester, amide, halogen, and sulfoxide.

(Preparation Example 3) As the charge transporting compound, 20 g of the low molecular weight compound-3 exemplified above was used. As a compound capable of reacting with the charge transporting compound, 0.5 g of divinylbenzene and 1.1 mg of benzoyl peroxide were used. Was added to prepare an oily mixture. The obtained oil-based mixed solution was emulsified and dispersed at a rotation speed of 8000 rpm by using 1.0 kg of a 1.0% aqueous solution of polyvinyl alcohol as an aqueous medium, and then subjected to normal pressure for 5 hours in a constant temperature bath at 80 ° C. After removing toluene and washing with distilled water, freeze-drying was performed to obtain 20 g of crosslinked charge transporting polymer particles having an average particle size of 0.8 μm. Regarding the solubility of the obtained charge transporting polymer particles in an organic solvent, the same results as in Preparation Example 1 were shown.

(Preparation Example 4) As the charge transporting polymer compound, the polymer compound Nos. 20 g of 8 was dissolved in 150 g of toluene to prepare an oily mixture. The obtained oily mixed solution was subjected to 8000 rpm in 1.0 kg of a 1.0% aqueous solution of polyvinyl alcohol as an aqueous medium.
After emulsifying and dispersing at a rotation speed of m, the toluene was removed at normal pressure for 3 hours in a thermostat at 60 ° C., washed with distilled water, freeze-dried, and the average particle size was 0.2 μm. 15 g of the charge transporting polymer particles were obtained.

Example 1 A mixture of 5 parts by weight of polyvinyl butyral resin (Eslec BM-S, manufactured by Sekisui Chemical Co., Ltd.), 92 parts by weight of n-butanol, and 3 parts by weight of the charge transporting polymer particles of Preparation Example 1 was ball milled. The mixture was dispersed for 24 hours to obtain a coating liquid. This coating solution was dip-coated on an Al plate and dried at 130 ° C. for 30 minutes to form a 1 μm-thick intermediate layer.
To a solution in which 8 parts by weight of a polycarbonate Z resin (Iupilon Z-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was previously dissolved in 90 parts of toluene, 3 parts by weight of chlorogallium phthalocyanine was added, and the mixture was dispersed with a sand mill for 24 hours to obtain a photosensitive material. A coating solution for a layer is prepared, applied on the intermediate layer by an applicating method, and dried by heating at 100 ° C. for 1 hour to form a photosensitive layer having a thickness of 15 μm. An electrophotographic photoreceptor of a mold was prepared.

The electrophotographic photoreceptor thus obtained was subjected to normal temperature and normal humidity (20 ° C., 20 ° C.) using an electrostatic copying paper tester (Electrostatic Analyzer EPA-8100, manufactured by Kawaguchi Electric Works). The electrophotographic properties were evaluated in an environment of 40% RH). After adjusting the corona discharge voltage and charging the photoconductor surface to 750 V, the halogen lamp light monochromatized to 750 nm through an interference filter was adjusted to have a light intensity of ² mW / m2 on the photoconductor surface. Irradiation was performed for 7 seconds, and a half-life exposure amount E50% was determined from a photoinduced potential decay curve. The potential 7 seconds after the start of exposure was defined as the residual potential. E50% was 6.5 mJ / m ² , and the residual potential was 80 V. An electrophotographic photoreceptor was prepared in the same manner except that an aluminum drum was used instead of the aluminum substrate, and a laser printer (La
ser Press 4105, manufactured by Fuji Xerox Co., Ltd.)
Mounted on. Since this laser printer was for a negatively charged photoreceptor, it was modified for a positively charged photoreceptor. When a print sample was taken and the image quality was evaluated, neither a white point nor a black point occurred, and an image of good image quality was obtained.

Comparative Example 1 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that no charge-transporting polymer was added, and evaluated in the same manner as in Example 1. As a result, the residual potential was 470V. Comparative Example 2 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the intermediate layer was not formed, and the image quality was evaluated in the same manner as in Example 1. As a result, black spots occurred in the image.

Example 2 An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the charge transporting polymer particles obtained in Preparation Example 2 were used instead of the charge transporting polymer particles obtained in Preparation Example 1. A body was prepared and evaluated in the same manner as in Example 1. As a result, E
50% was 7.2 mJ / m ² , and the residual potential was 50 V. Example 3 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the charge transporting polymer particles obtained in Preparation Example 3 were used instead of the charge transporting polymer particles obtained in Preparation Example 1. Then, evaluation was performed in the same manner as in Example 1. As a result, E50%
Was 6.8 mJ / m ² and the residual potential was 60 V.

Example 4 To 10 parts by weight of the charge-transporting polymer particles obtained in Preparation Example 4, 20 parts by weight of a zirconium alkoxide compound (trade name: ORGATICS ZC540, manufactured by Matsumoto Pharmaceutical Co., Ltd.) and γ-aminopropyltriethoxysilane (Product name:
A1100, manufactured by Nippon Unicar) 2 parts by weight and polyvinyl butyral resin (Eslec BM-S, manufactured by Sekisui Chemical)
1.5 parts by weight and 60 parts by weight of n-butanol were added, and 24
The mixture was dispersed in a sand mill for an hour to prepare an intermediate layer coating solution. The coating solution was applied on an aluminum plate by a dip coating method, and dried by heating at 170 ° C. for 10 minutes to form an intermediate layer having a thickness of 2.0 μm. Next, 4 parts by weight of chlorogallium phthalocyanine microcrystals were added to vinyl chloride-
Mix with 2 parts by weight of vinyl acetate copolymer (trade name: UCAR Solution Vinyl Resin VMCH, manufactured by Union Carbide), 67 parts by weight of xylene and 33 parts by weight of butyl acetate, and treat with 1 mmφ glass beads with a sand grinder for 2 hours. After dispersing, the obtained coating solution is applied on the intermediate layer by a dip coating method,
For 10 minutes to form a charge generation layer having a thickness of 0.2 μm.

Next, a coating solution prepared by dissolving 20 parts by weight of a compound composed of a repeating unit represented by the following structural formula and having a weight average molecular weight of 80,000, which is a polymer charge transporting material, in 80 parts by weight of monochlorobenzene was added to the above-mentioned charge generating layer. The resultant was applied by a dip coating method and dried by heating at 135 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm. Thus, an electrophotographic photosensitive member having a layer configuration shown in FIG. 2 was produced.

Embedded image The evaluation was performed in the same manner as in Example 1 except that the charging polarity of the electrophotographic photosensitive member thus obtained was negative. E
50% was 5.2 mJ / m ² , and the residual potential was −70 V. An electrophotographic photoreceptor was prepared in the same manner except that an aluminum drum was used instead of the aluminum substrate, and a laser printer (Laser Press 41) was used.
05, manufactured by Fuji Xerox Co., Ltd.), a print sample was taken, and the image quality was evaluated. As a result, in the obtained image, neither a white point nor a black point occurred, and the image had good image quality.

Comparative Example 3 An electrophotographic photosensitive member was prepared in the same manner as in Example 4 except that the charge transporting polymer was not added, and evaluated in the same manner as in Example 2. As a result, E50% was 8.2 mJ / m ² ,
The residual potential was -180V. Comparative Example 4 An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the intermediate layer was not applied, and the image quality was evaluated in the same manner as in Example 4. As a result, black spots occurred in the obtained image.

[0067]

The electrophotographic photoreceptor of the present invention has an excellent chargeability and a low residual potential because an intermediate layer containing charge transporting polymer particles is provided between the conductive substrate and the photosensitive layer. It has characteristics, and as is clear from the comparison between the above embodiment and the comparative example, it is possible to form an image free from image quality defects such as black spots and white spots.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an example having a single-layered photosensitive layer of an electrophotographic photosensitive member of the present invention.

FIG. 2 is a schematic cross-sectional view of an example having a photosensitive layer having a laminated structure of the electrophotographic photosensitive member of the present invention.

FIG. 3 is a schematic sectional view of another example having a photosensitive layer having a laminated structure of the electrophotographic photosensitive member of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Charge transportable polymer particle, 2 ... Conductive support, 3 ...
Photosensitive layer, 4 ... intermediate layer, 5 ... charge generation layer, 6 ... charge transport layer.

Claims (4)

[Claims] 1. An electrophotographic photosensitive member having at least an intermediate layer and a photosensitive layer provided on a conductive substrate, wherein the intermediate layer contains charge transporting polymer particles. 2. The electrophotographic photosensitive member according to claim 1, wherein the charge transporting polymer particles contain a charge transporting polymer compound represented by the following general formulas (I) to (VI). body. Embedded image [Wherein at least one of A and B represents a divalent group represented by the following general formulas (1) to (7);
The other represents a divalent aliphatic hydrocarbon group or an aromatic hydrocarbon group which may be substituted, and A ′ represents a monovalent group represented by the following formulas (8) to (16); Represents an integer of 5 to 5000. Embedded image Embedded image In the formula, R _{1 to} R ₄ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a substituted amino group, a halogen atom,
Or X represents a substituted or unsubstituted aryl group, and X represents a substituted or unsubstituted divalent aromatic ring-containing group represented by the following formulas (a) to (f): (Wherein, R _{9 to} R ₁₁ each represent a phenyl group, a substituted or unsubstituted aralkyl group or a halogen atom;
a and b each represent an integer of 0 or 1;
Represents a group selected from the following formulas (g) to (p). Embedded image (Where c represents an integer of 1 to 10, d represents an integer of 1 to 3), and T represents an optionally branched alkylene group having 1 to 10 carbon atoms, an arylene group, or an alkylenecarbonyl group. , An arylenecarbonyl group, an alkyleneimino group, an aryleneimino group, an alkyleneoxy group or an aryleneoxy group, and k and l are each 0
Or an integer selected from 1. Also, R ₅ and R
₆ represents an alkyl group, an aryl group, a halogen atom, a nitro group, an acyl group or a cyano group, X ′ represents an oxygen atom, (Where R ₁₂ and R ₁₃ each represent an alkyl group or an aryl group), and Y is> C = X ′, an oxygen atom, a sulfur atom, —SO ₂ — or —NR ₁₄ — (where, X ′ has the same meaning as above, and R ₁₄ represents a hydrogen atom, an alkyl group, an aryl group or an acyl group), and m
And n each represent an integer of 0 to 2. ｝ Embedded image (Wherein, R _{1 to} R ₆ , X, T, X ′, Y, 1, k, m and n have the same meanings as described above, provided that when k = 0, X is bonded to a hydrogen atom .R _{1 'to} form a terminal group and
To R _{4 ′} each independently represent a hydrogen atom, an alkyl group, an alkoxy group, a substituted amino group, a halogen atom, or a substituted or unsubstituted aryl group, and R ₇ and R ₈ represent an alkyl group, a halogen atom, a nitro group, an acyl group or a cyano group, Z is an oxygen atom or _{= C (CN) 2, Y} ' is, -COO (CH _2)
t - or _{-C 6 H 4 -COO (CH 2} ) t -] ( although, t means an integer of 1 to 6.) 3. The electrophotographic photoconductor according to claim 1, wherein the intermediate layer is a charge injection layer. 4. The electrophotographic photoreceptor according to claim 1, wherein the intermediate layer is a charge transporting polymer particle layer in which charge transporting polymer particles are dispersed in an electrically insulating resin.