JP2852432B2 - Electrophotographic photoreceptor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly, to an electrophotographic photoreceptor having improved charging start-up characteristics, durability and image quality.

[Prior Art] In recent years, with the market expansion of copiers, printers, and the like, applications have been diversified. In order to meet those needs, many studies on electrophotographic photoreceptors using an organic photoconductive material instead of a conventional inorganic photoconductive material have been made. That is, since various kinds of organic photoconductive materials can be obtained by a combination of synthetic substances and synthesis conditions, the selection range of the materials is widened, and various characteristics required in the electrophotographic process, for example, charge retention. Force, surface strength, sensitivity and stability during repeated use can be improved or improved. An electrophotographic photoreceptor using an organic photoconductive material also has advantages of good productivity and high environmental safety.

Generally, an organic photoconductive photoreceptor comprises a photoconductive organic semiconductor, that is, a photosensitive layer containing a carrier generating substance and a carrier transporting substance as essential components.

Also, a function-separated type photoconductor in which a photosensitive layer is divided into two layers and a carrier generation layer and a carrier transport layer are separately configured has been proposed. Since the carrier generation function and the carrier transport function can be separately assigned to different substances, it is easy to control the characteristics between electrophotographic characteristics such as sensitivity and charging characteristics, and the photosensitive and photosensitive materials have high sensitivity and high durability. It is expected that the body will be obtained. Particularly, in the case of a negatively charged photoreceptor, a carrier generation layer is laminated on a conductive support, and a carrier transport layer is laminated thereon. However, they do not yet have sufficient performance in charging characteristics and image quality characteristics. That is, in the conventional photoreceptor, when a charge is applied to the photoreceptor by a charging method, a leakage current occurs and the charging rise is not sufficient, and therefore, a sufficient charging potential required at the time of exposure cannot be obtained. In addition, the barrier properties of the intermediate layer were not sufficient and minute image defects occurred. That is, image defects appearing as white spots in the normal development and black spots in the reversal development.

Generally, the charge generation layer is a very thin layer on the conductive layer, for example,
Since the substrate is provided with a thickness of about 0.5 μm, very small defects, dirt, deposits or scratches on the substrate surface affect the uniformity of the thickness of the charge generation layer. If the thickness of the charge generation layer is non-uniform, the sensitivity of the photoreceptor will be uneven. Therefore, it is required to make the thickness of the charge generation layer as uniform as possible. For this reason, it has been proposed to provide an intermediate layer having a function as a barrier layer and a function as an adhesive layer between the charge generation layer and the conductive layer.

[Problems to be Solved by the Invention] Heretofore, it has been known that polyurethane, polyamide, polyvinyl alcohol, epoxy resin, casein, methylcellulose, nitrocellulose, phenol resin or the like is used as an intermediate layer provided between the photosensitive layer and the conductive layer. However, the photoreceptor using these layers has a drawback that, when used repeatedly, a rise in a light portion potential and a change in a dark portion potential occur, and at the same time, a discharge breakdown of the photosensitive layer is caused at this time. I have. In particular, the photoreceptor using the conventional intermediate layer, when used repeatedly in a low-humidity environment, has a noticeable increase in the bright part potential and a remarkable fluctuation in the dark part potential. And the adhesiveness between the photosensitive layer and the conductive layer is not yet sufficient.

An object of the present invention is to solve the above-mentioned problems, to provide an electrophotographic photoreceptor having excellent charge rising characteristics and environmental stability during repeated use, and which does not generate black spots or the like by reversal development. To provide.

[Means for Solving the Problems] An object of the present invention is to provide an electrophotographic photoreceptor comprising at least a substrate, an intermediate layer and a photosensitive layer, wherein at least one of the intermediate layer and the photosensitive layer is an aliphatic aminocarboxylic acid (a component). Derived from an aliphatic dicarboxylic acid (component b) and an amine having a piperazine ring represented by the following general formula (component c), and the ratio of the components a, b and c is a: b:
The electrophotographic photoreceptor is characterized by containing a polyamide having c = 0.6 to 10.0: 1.0: 0.5 to 1.0.

[Wherein R ₁ , R ₂ and R ₃ are each a hydrogen atom or CH ₂ ) _m NH ₂
Represents Here, m represents an integer of 0 to 20. Hereinafter, the present invention will be described in more detail.

Aliphatic aminocarboxylic acid (a component) according to the present invention,
Aliphatic dicarboxylic acid (component b) and the following general formula [I]
The polyamide derived from an amine having a piperazine ring (component (c)) is particularly used as a binder in the intermediate layer and / or the photosensitive layer.

General formula [I] (Wherein R ₁ , R ₂ and R ₃ are each a hydrogen atom or CH ₂ ) _m NH ₂ . Here, m represents an integer of 0 to 20. The aliphatic aminocarboxylic acid (component a) and the aliphatic dicarboxylic acid (component b) each preferably have an integer of 4 to 12 carbon atoms.

Specific examples of the aliphatic aminocarboxylic acid (component (a)) include, for example, ω-aminobutyric acid, ω-aminovaleric acid, ω-aminocaproic acid, ω-aminoenanthic acid, ω
-Aminocaprylic acid, ω-aminopelargonic acid, ω-aminocapric acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, butyrolactam, valeryloractam, caprolactam, enantolactam, caprylactam, laurolactam and the like. Among them, ω-aminocaproic acid is preferable.

Specific examples of the aliphatic dicarboxylic acid (component (b)) include, for example, succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, and the like. Particularly preferred are adipic acid and azelaic acid. And sebacic acid.

Examples of the amine (component c) having a piperidine ring represented by the general formula [I] include piperidine, N, N'-bis (aminomethyl) piperazine, N, N'-bis (β-aminoethyl) piperazine, N, N'-bis (β-aminoethyl) methylpiperazine, N- (aminomethyl) -N '-(β-
Aminoethyl) piperazine, N, N′-bis (γ-aminopropyl) piperazine, N- (β-aminoethyl) piperazine, N- (γ-aminopropyl) piperazine, N-
(Ω-aminohexyl) piperazine, N- (δ-aminocyclohexyl) piperazine, N- (β-aminoethyl) -3-methylpiperazine, N- (β-aminoethyl) -2,5-dimethylpiperazine, N- (Β-aminopropyl) -3-methylpiperazine, N- (γ-aminopropyl) -2,5-dimethylpiperazine, 1,4-bis (amenomethyl) piperidine, 1,4-bis (β-aminoethyl) piperidine 1,4-bis (γ-aminopropyl) piperidine, 1-aminomethyl-4- (β-aminoethyl) piperidine, 1- (β-aminoethyl) -4-aminomethylpiperidine, 4-aminomethylpiperidine, 4
Diamines such as-(β-aminoethyl) piperidine and 4- (γ-aminopropyl) piperidine are preferable, and N, N′-bis (γ-aminopropyl) piperazine and N- (β-aminoethyl) are preferred. Piperazine, piperazine, 4-aminomethylpiperazine is used.

In the present invention, in order to obtain a polyamide having a specific property, the ratio used for the polymerization reaction of the component a, the component b, and the component c is a: b: c = 0.6 to 10.0: 1.0: 0.5 to 2.0. It is particularly preferable that a: b: c = 0.6 to 3.0: 1: 0.5 to 1.

The polymerization reaction for obtaining the polyamide used in the present invention proceeds by two operations. One is a homogenization operation in which the starting materials are supplied to a heatable vessel to form a transparent homogeneous reaction mixture under heating and stirring, and the other is that the reaction mixture obtained by the homogenization operation is subjected to high vacuum. This is a polymerization operation in which heating and stirring are performed.

In the homogenization operation, the starting materials are homogeneously mixed and accompanied by some reaction.

The homogenization is carried out at 150 to 260 ° C., preferably 180 to 250 ° C., under normal pressure for about 20 to 80 minutes under an inert gas atmosphere, and the polymerization is carried out in the presence of a polymerization catalyst at 220 to 290 ° C., preferably 240 to 285 ° C. ° C
The mixture is heated under high vacuum for 2 to 7 hours and stirred until a predetermined degree of polymerization is reached. Here, high vacuum is about 15mmHg
Hereinafter, it refers to a reduced pressure state of preferably 5 mmHg or less, more preferably 1 mmHg or less.

As the polymerization catalyst, a titanium-based catalyst, a tin-based catalyst, a zirconium-based catalyst, a hafnium-based catalyst, a lead-based catalyst, and the like are used.

Further, preferably in the polymerization system, 4,4'-
Bis (2,6-di-tert-butylphenol), 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3
(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] Various hinders such as methane and N, N'-hexamethylene-bis (3,5-di-tert-butyl-4-hydroxyhydrocinnamic acid amide) Phenols or N, N'-
Bis (β-naphthyl) -p-phenylenediamine and 4,
Add aromatic amines such as 4'-bis (4-α, a-dimethylbenzyl) diphenylamine.

Further, a polyfunctional compound such as trimesic acid, glycerin, pentaerythritol or the like may be added to the polymerization reaction system as a thickening agent within a range in which the polyetheresteramide does not gel.

(Synthesis of Polyamide Compound of Example-1) ε-amino-n-caproic acid, adipic acid and N-
6 parts of (β-aminoethyl) piperazine together with 0.20 part of “Ilukanox” 1098 (antioxidant) and 0.05 part of tetrabutyl titanate catalyst were charged into a reaction vessel equipped with a helical lion stirring blade, purged with N ₂ and 240 ° C. After heating and stirring for 40 minutes to obtain a transparent homogeneous solution, the mixture was brought to a polymerization condition of 260 ° C. and 0.5 mmHg or less according to a heating and decompression program. When the reaction was carried out under these conditions for 5 hours and 30 minutes, a viscous colorless and transparent solution polymer was obtained. The polymer was discharged in a gut shape on a cooling belt and pelletized.

In the photoreceptor of the present invention, an organic pigment as shown in the following representative examples is used as a carrier generating substance.

(1) Azo pigments such as monoazo pigments, bisazo pigments, triazo pigments and metal complex salt azo pigments (2) Perylene pigments such as perylene anhydride and perylene imide (3) Anthraquinone derivatives, anthantrone derivatives, dibenzpyrene Polycyclic quinone pigments such as quinone derivatives, pyranthrone derivatives, biolanthrone derivatives and isoviolanthrone derivatives; (4) indigoid pigments such as indigo derivatives and thioindigo derivatives; and (5) phthalocyanine pigments such as metal phthalocyanines and metal-free phthalocyanines. In the electrophotographic photoreceptor, an organic pigment such as a fluorenone disazo pigment, a polycyclic quinone pigment, a fluorenylidene disazo pigment, a metal-free phthalocyanine pigment or an oxytitanyl phthalocyanine pigment is used as a charge generating substance. Door is preferable. In particular, the following fluorenone-based disazo pigments, polycyclic quinone-based pigments,
When fluorenylidene disazo pigments, X- and τ-type metal-free phthalocyanines and oxytitanyl phthalocyanine pigments described in JP-A-64-17066 are used in the present invention, sensitivity, durability, image quality and the like are remarkably improved. Show the effect.

The fluorenone-based disazo pigment used in the present invention is represented by the following general formula [II].

General formula [II] [X ₁ and X ₂ each represent a halogen atom, an alkyl group, an alkoxy group, a nitro group, a cyano group, a hydroxy group or a substituted or unsubstituted amino group.

p and q each represent an integer of 0, 1 or 2, and when p and q are 2, X ₁ and X ₂ may be the same or different groups. A represents a group represented by the following general formula [II-1].

General formula [II-1] (In the formula, Ar represents a fluorinated hydrocarbon group or an aromatic carbocyclic group having a substituent or an aromatic heterocyclic group. Z represents a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic group. Represents a group of non-metallic atoms necessary for forming a ring.) M and n each represent an integer of 0, 1 or 2.
However, m and n do not become 0 at the same time. Specific examples of the fluorenone-based disazo pigment used in the invention are shown below, but the invention is not limited thereto.

The fluorenone-based disazo pigment represented by the general formula [II] used in the present invention is easily synthesized by a known method, for example, by a method described in Japanese Patent Application No. 62-304862.

The polycyclic quinone pigment used in the present invention is represented by the following general formulas [A] to [C].

(In each formula, X represents a halogen atom, a nitro group, a cyano group, an acyl group, or a carboxy group, n represents an integer of 0 to 4, and m represents an integer of 0 to 6.) Specific examples of the polycyclic quinone pigment used in the present invention represented by [A] to [C] are shown below, but are not limited thereto.

Specific examples of the anthantrone-based pigment represented by the general formula [A] are as follows.

Specific compound examples of the dibenzpyrenequinone pigment represented by the general formula [B] are as follows.

Specific examples of the pyranthrone-based pigment represented by the general formula [C] are as follows.

The polycyclic quinone pigments represented by the general formulas [A] to [C] used in the present invention can be easily synthesized by a known method.

The fluorenylidene disazo pigment used in the present invention is represented by the following general formula [III].

General formula [III] Z: atom group necessary to constitute a substituted / unsubstituted aromatic carbocyclic ring or substituted / unsubstituted aromatic heterocyclic ring Y: hydrogen atom, hydroxy group, carboxy group, or ester group, sulfo group, substituted / unsubstituted group Unsubstituted carbamoyl group or substituted / unsubstituted sulfamoyl group R ₁ : hydrogen atom, substituted / unsubstituted alkyl group, substituted / unsubstituted amino group, substituted / unsubstituted carbamoyl group, carboxy group or ester group thereof or Cyano group Ar: substituted / unsubstituted aryl group R ₂ : substituted / unsubstituted alkyl group, substituted / unsubstituted aralkyl group or substituted / unsubstituted aryl group. Specific examples of the disazo pigments effective for the present invention represented by the general formula [III] include, for example, those represented by the following structural formulas, and thereby, the disazo pigments to be used in the present invention. The pigment is not limited.

As the non-metallic phthalocyanine-based pigment that can be used in the present invention, all non-metallic phthalocyanine having photoconductivity and derivatives thereof can be used, for example, α-type, β-type,
τ, τ 'type, η, η' type, X type, and Japanese Patent Application No. 60-242883
The crystal forms and derivatives thereof described in (1) can be used. In particular, it is desirable to use the τ, X, K / RX type. The X-type metal-free phthalocyanine is described in US Pat. No. 3,357,989, and the τ-type metal-free phthalocyanine is described in JP-A-58-182639. K / R-X type is Japanese Patent Application No. 60
As described in −242883, CuKα, at a Bragg angle (2θ ± 0.2 degrees) with respect to 1.541 ° X-rays, is 7.7,9.2.16.
It has a main peak at 8,17.5, 22.4, 28.8 degrees, and a peak intensity ratio of 16.8 degrees to a peak intensity of 9.2 degrees is 0.8 to 1.0.
And the peak intensity ratio of 28.8 degrees to 22.4 degrees is 0.
It is a phthalocyanine characterized by being 4 or more.

The oxytitanyl phthalocyanine used in the present invention is represented by the following general formula.

(Wherein, X ₁ , X ₂ , X ₃ , and X ₄ each independently represent Cl or Br, and n, m, l, and k each independently represent a number from 0 to _4. ) Of the oxytitanyl phthalocyanines used, particularly preferred ones are oxytitanyl phthalocyanine (TiOPc) and titanyl chlorophthalocyanine (TiOPcC).
l) and mixtures thereof.

As these oxytitanyl phthalocyanines, those having different crystal types disclosed in the following patents are known. For example, JP-A-61-239248, JP-A-62-6709
No. 43, JP-A-62-272272, JP-A-63-116158
Or JP-A-64-17066.

The photoreceptor of the present invention has, for example, the configuration shown in FIG.

In this photoreceptor, a charge generation layer 6 is provided on a conductive support (substrate) 1 via the above-described intermediate layer 7, and a charge transport layer 4 is provided on the charge generation layer 6. Reference numeral 8 denotes a photosensitive layer. Accordingly, since the intermediate layer 7 is provided between the charge generation layer 6 and the support 1, the injection of non-uniform holes from the support side shown in FIG. Electrons, which are photocarriers, can be efficiently transported to the support side.

The photoreceptor of the present invention has a structure other than the above-described structure (that is, a charge transport layer is laminated on a charge generation layer) as shown in FIG.
It may comprise a single photosensitive layer 8 in which a charge generating substance and a charge transporting substance are mixed. Further, as shown in FIG. 3, the charge generating layer 6 and the charge transporting layer 4 may be formed upside down (for positive charging).

Further, in the photoreceptor of the present invention, a protective layer (protective film) may be formed on the surface of the photoreceptor for improving printing durability and the like, for example, a synthetic resin film may be coated.

The intermediate layer according to the present invention is an alcohol solution such as methanol, ethanol or butanol containing the polyamide, a dip coating method, a roll coating method,
It is obtained by coating on a substrate using a coating method such as a spray coating method, a wire bar coating method, a bead coating method or a curtain coating method. The film thickness is generally from 0.1 to 5 µm, preferably from 0.5 to 3 µm. When the polyamide is dissolved in alcohol, an aromatic hydrocarbon such as toluene or xylene may be added for improving the solution stability.

Further, the intermediate layer according to the present invention may contain other general binders as needed, as long as the function as a barrier layer is not impaired. At this time, the polyamide is contained in an amount of 5 to 100% by weight, preferably 20 to 100% by weight based on the total weight of the intermediate layer.

In the present invention, the charge generation layer is typically formed by dispersing the organic pigment in a suitable dispersion medium or solvent alone or with a suitable binder resin, for example, by dip coating, spray coating, blade coating, or roll coating. It can be provided by a method of coating and drying on the intermediate layer or the charge transport layer by, for example,

The organic pigment used in the present invention is, for example, a ball mill, a homomixer, a sand mill, an ultrasonic disperser, an attritor, after being made into fine particles of an appropriate particle size using a sand grinder, and the like, may be dispersed in a dispersion medium. Good.

As a dispersion medium of the organic pigment used in the present invention, for example, hexane, benzene, toluene, hydrocarbons such as xylene, methylene chloride, methylene bromide, 1,
2-dichloroethane, syn-tetrachloroethane, cis-
1,2-dichloroethylene, 1,1,2-trichloroethane, 1,
Halogenated hydrocarbons such as 1,1-trichloroethane, 1,2-dichloropropane, chloroform, bromoform, and chlorobenzene; ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; methanol and ethanol; Propanol, butanol, cyclohexanol, heptanol, ethylene glycol, methyl cellosolve, ethyl cellosolve,
Alcohols such as cellosolve acetate and derivatives thereof, ethers such as tetrahydrofuran, 1,4-dioxane, furan and ralfural, acetals, amines such as pyridine, n-butylamine, diethylamine, ethylenediamine, isopropanolamine, N, N-dimethylformamide Other examples include nitrogen compounds such as amides and the like, fatty acids and phenols, and sulfur and phosphorus compounds such as carbon disulfide and triethyl phosphate.

In the present invention, the charge generation layer may contain one or more kinds of electron accepting substances for the purpose of improving sensitivity, reducing residual potential, or reducing fatigue during repeated use.

Electron accepting substances that can be used here include
For example, succinic anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, pyromellitic anhydride, merit anhydride Acid, tetracyanoethylene, tetracyanoquinodimethane, o-dinitrobenzene, m-dinitrobenzene, 1,3,5-trinitrobenzene, paranitrobenzotonyl, picryl chloride, quinone chlorimide, chloranil, bulmanyl, dichlorodicyano Parabenzoquinone, anthraquinone, dinitroanthraquinone, 2,7
-Dinitrofluorenone, 2,4-7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, 9-fluorenylidene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene- [dicyanomethylenemalonodinitrile] , Picric acid, o-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid,
Examples thereof include 3,5-dinitrosalicylic acid, phthalic acid, melitic acid, and other compounds having a high electron affinity. The addition ratio of the electron-accepting substance is as follows: the organic pigment used in the present invention: the electron-accepting substance = 100: 0.01 by weight.
200200, preferably 100: 0.1-100.

This electron accepting substance may be added to the charge transport layer.
The ratio of addition of the electron accepting substance to such a layer is 100: 0.01 to 100, preferably 100: 0.1 to 50, in terms of weight ratio, of total charge transporting substance: electron accepting substance.

When the electrophotographic photoreceptor of the present invention has a laminated structure, the weight ratio of binder: charge generating substance: charge transporting substance in the charge generation layer is from 0 to 100: 1 to 500: 0 to 500. Further, in the present invention, when the polyamide is used in the charge generation layer, the ratio thereof is the binder in the charge generation layer: the polyamide = 0 to 100: 1, and when the polyamide is used in the charge transport layer, the charge transport layer Binder in: Polyamide = 0 to 0
100: 1, and the ratio in the total binder is binder: polyamide = 0 to 100: 1.

If the content of the charge generating substance is less than this, photosensitivity is low and the residual potential is increased, and if it is more than this, dark decay and accepting potential are reduced.

The thickness of the charge generation layer formed as described above is preferably 0.01 to 10 μm, and particularly preferably 0.1 to 5 μm.

Further, the charge transport layer can be formed by applying and drying a material obtained by dissolving and dispersing a charge transport substance alone or in an appropriate solvent or dispersion medium together with the above-mentioned binder resin. As the dispersion medium to be used, the dispersion medium used in dispersion of the charge generation substance can be used.

The charge transporting substance that can be used in the present invention is not particularly limited, and examples thereof include an oxazole derivative, an oxadiazole derivative, a thiazole derivative, a thiadiazole derivative, a triazole derivative, an imidazole derivative, an imidazolone derivative, an imidazolidine derivative, and a bisimidazolidine derivative. , Styryl compounds, hydrazone compounds, pyrazoline derivatives, amine derivatives, oxazolone derivatives,
Benzothiazole derivatives, benzimidazole derivatives,
Quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, and the like.

As the charge transporting material used in the present invention, besides having excellent ability to transport holes generated during light irradiation to the support side, those suitable for combination with the organic pigment used in the present invention are preferably used, Preferred examples of such a charge transport material include the following general formulas (TA) and (T-
B) and (TC).

General formula (TA) However, Ar ₁ , Ar ₂ , Ar ₄ each represents a substituted or unsubstituted aryl group, Ar ₃ represents a substituted or unsubstituted arylene group, R ₁ is a hydrogen atom, a substituted or unsubstituted alkyl group, or Represents a substituted or unsubstituted aryl group.

Specific examples of such compounds are described in detail in JP-A-58-65440, pp. 3-4, and JP-A-58-198043, pp. 3-6.

General formula (TB) However, R ₁ is a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group, R ₂ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, The details are described in JP-A-58-133462 and JP-A-58-166354.

General formula (TC) However, R ₁ is a substituted or unsubstituted aryl group,
R ₂ is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, or a hydroxy group, R ₃
Represents a substituted or unsubstituted aryl group or a substituted or unsubstituted heterocyclic group. Methods for synthesizing these compounds and examples thereof are described in detail in JP-B-57-148750, which can be incorporated in the present invention.

Other preferred charge transporting substances of the present invention include hydrazone compounds described in JP-A-57-67940, JP-A-59-15252, and JP-A-57-101844, respectively.

The charge transporting material is preferably 20 to 200 parts by weight, particularly preferably 30 to 1 part by weight per 100 parts by weight of the binder resin in the charge transporting layer.
50 parts by weight.

The thickness of the formed charge transport layer is preferably 5 to 50 μm.
m, particularly preferably 5 to 30 μm.

In the case of a single-layer function-separated electrophotographic photoreceptor using the organic pigment used in the present invention, the ratio of the binder: the organic pigment used in the present invention: the carrier transport material is 0.
~ 100: 1 ~ 500: 0 ~ 500 is preferred, the thickness of the formed photosensitive layer is preferably 5 ~ 50μm, particularly preferably 5 ~ 30μm
m.

As the binder resin usable for the photosensitive layer, the protective layer, and the intermediate layer, not only the polyamide resin of the present invention, but also, for example, polystyrene, polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral Resin, epoxy resin,
Polyurethane resin, phenolic resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, addition polymerization type resin such as melamine resin, polyaddition type resin, polycondensation type resin, and two or more of repeating units of these resins Insulating resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, and high molecular organic materials such as poly-N-vinyl carbazole Semiconductors.

Organic amines can be added to the photosensitive layer of the present invention for the purpose of improving the charge generation function of the charge generation substance, and it is particularly preferable to add a secondary amine. These compounds are described in JP-A-59-218447 or JP-A-62-8160.

Further, in the photosensitive layer of the present invention, an antioxidant can be added for the purpose of preventing ozone deterioration.

Representative specific examples of such antioxidants are shown below, but are not limited thereto.

Group (I): hindered phenols, Group (II): paraphenylenediamines, Group (III): hydroquinones, Group (IV): organic sulfur compounds, Group (V): organic phosphorus compounds .

These compounds are disclosed, for example, in JP-A-63-18354.

These compounds are known as antioxidants for rubbers, plastics, oils and the like, and commercially available products can be easily obtained.

These antioxidants may be added to any of the charge generation layer, the charge transport layer, and the protective layer, but are preferably added to the charge transport layer. In this case, the amount of the antioxidant added is 0.1 to 100 parts by weight, preferably 1 to 50 parts by weight, particularly preferably 5 to 25 parts by weight based on 100 parts by weight of the charge transporting substance.

In addition, the photoreceptor of the present invention may further contain, if necessary, an ultraviolet absorber, an antioxidant and the like for the purpose of protecting the photosensitive layer, and may contain a dye for correcting color sensitivity.

Next, as the conductive support for supporting the photosensitive layer, a metal plate such as aluminum or nickel, a metal drum or metal foil, aluminum film, tin oxide, a plastic film on which indium oxide or the like is deposited, or a paper coated with a conductive material. , Plastic or other films or drums can be used.

The electrophotographic photoreceptor containing the organic pigment used in the present invention can satisfactorily respond to visible light and near-infrared light, but preferably has an absorption maximum at a wavelength of about 400 to 850 μm. I have.

As a light source having such a wavelength, a halogen lamp, a fluorescent lamp, a tungsten lamp, an argon laser,
Gas lasers such as helium and neon lasers and semiconductor lasers are used.

The electrophotographic photoreceptor of the present invention is configured as described above, and as is clear from the examples described later, is excellent in charging start-up characteristics, charging characteristics, sensitivity characteristics, and image forming characteristics, especially when used repeatedly. Also, it has little fatigue deterioration and excellent durability. Further, in reversal development, an excellent electrophotographic photoreceptor with little black spots can be obtained.

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples.
This does not limit the embodiments of the present invention.

Example 1 ε-amino-n-caproic acid, adipic acid and N-
(Β-Aminoethyl) piperazine 30: 1 copolymerized with a monomer composition of 1: 1: 1 was stirred into a 800 ml methanol EL standard (Kanto Chemical Co., Ltd.) heated to 50 ° C. and dissolved. I let it. After cooling to room temperature, 200 ml of 1-butanol special grade (Kanto Chemical Co., Ltd.) was added. Then, dip-coat on an aluminum drum with a diameter of 80 mm,
A thick intermediate layer was formed.

Next, 20 g of a fluorenone-based disazo pigment (Exemplified Compound 23) as a charge generating substance and a polyvinyl butyral resin STEC BX-1 (manufactured by Sekisui Chemical Co., Ltd.) as a binder
10 g of methyl ethyl ketone (Kanto Chemical EL standard) 100
The solution was dissolved in 0 ml and milled for 24 hours in a ball mill to obtain a coating solution for the charge generation layer. This was dip-coated on the intermediate layer to form a 0.3 μm thick charge generation layer. Thereafter, 120 g of a charge transporting material having the following structural formula and a polycarbonate resin Iupilon Z-200 (manufactured by Mitsubishi Gas Chemical Company) 165
g was dissolved in 1,000 ml of 1,2-dichloroethane special grade (manufactured by Kanto Chemical Co., Ltd.) to obtain a charge transport layer coating solution. This was dip-coated on the charge generation layer and dried at 100 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm. Thus, a photoreceptor having an intermediate layer, a charge generation layer, and a charge transport layer sequentially laminated was prepared.

Example 2 A photoconductor having an intermediate layer, a charge generation layer and a charge transport layer sequentially laminated in the same manner as in Example 1 except that a fluorenone-based disazo pigment (exemplified compound 24) was used as a charge generation material was prepared. .

Example 3 A photoconductor comprising an intermediate layer, a charge generation layer, and a charge transport layer sequentially laminated in the same manner as in Example 1 except that a fluorenylidene-based disazo pigment (exemplified compound III-8) was used as a charge generation material was prepared. Created.

Example 4 Polyamide copolymerized with a monomer composition of e-amino-n-caproic acid, sebacic acid and N, N'-bis (γ-aminopropyl) piperazine in a ratio of 0.7: 1: 1 as a binder for the intermediate layer A photoconductor was prepared by sequentially stacking an intermediate layer, a charge generation layer, and a charge transport layer in the same manner as in Example 1 except for using.

Example 5 11-aminoundecanoic acid as a binder for the intermediate layer,
Intermediate layer-charge generation layer-charge in the same manner as in Example 1 except that a polyamide copolymerized with a monomer composition having a ratio of azelaic acid and N- (β-aminoethyl) piperazine of 2: 1: 1 was used. A photoconductor was prepared by sequentially stacking transport layers.

Example 6 An intermediate layer was formed in the same manner as in Example 1.

Polycyclic quinone pigments (Exemplified Compound A)
3) 20g and polycarbonate resin L as binder
10 g of -1250 (manufactured by Teijin Chemical Co., Ltd.) was dissolved in 1,2-dichloroethane special grade (manufactured by Kanto Kagaku Co., Ltd.) and milled for 24 hours with a ball mill to obtain a coating solution for the charge generation layer. This was dip-coated on the intermediate layer to form a 0.3 μm thick charge generation layer.

Next, 120 g of a charge transporting material having the following structural formula and 165 g of a polycarbonate resin Iupilon Z-200 (manufactured by Mitsubishi Gas Chemical Company) were mixed with 1,2-dichloroethane special grade (manufactured by Kanto Chemical Co., Ltd.) 1
000 ml to obtain a charge transport layer coating solution. This was dip-coated on the charge generation layer and dried at 100 ° C. for 1 hour to form a charge transport layer having a thickness of 20 μm. Intermediate layer
A photoreceptor was formed by sequentially laminating a charge generation layer and a charge transport layer.

Example 7 As a binder for the intermediate layer, a polyamide copolymerized with a monomer composition of aminovaleryl lactam (a), glutaric acid (b) and N- (β-aminoethyl) piperazine in a ratio of 1: 1: 1 was used. Except for the above, a photoconductor was prepared by sequentially laminating an intermediate layer, a charge generation layer and a charge transport layer in the same manner as in Example 1.

Example 8 A polyamide copolymerized with a monomer composition of aminocaprolactam (a), azelaic acid (b) and N- (β-aminoethyl) piperazine in a ratio of 1: 1: 1 was used as a binder for the intermediate layer. In the same manner as in Example 1, a photoconductor was prepared by sequentially laminating an intermediate layer, a charge generation layer and a charge transport layer.

Examples 9 to 11 The ratios of ε-amino-n-caproic acid, adipic acid and N- (β-aminoethyl) piperazine as binders for the intermediate layer were 6: 1: 1, 9.5: 1.1 and 1: 1: 2, respectively. In the same manner as in Example 1 except that the polyamide copolymerized with the monomer composition was used, a photoconductor was prepared by sequentially laminating an intermediate layer, a charge generation layer and a charge transport layer.

Example 12 As a binder for the intermediate layer, 30 g of ethylene-vinyl acetate copolymer Sumitate KA20 (manufactured by Sumitomo Chemical Co., Ltd.) was added to 1000 ml of toluene special grade (manufactured by Kanto Kagaku Co., Ltd.) heated to 50 ° C. with stirring to dissolve. After cooling to room temperature, it was dip-coated on an aluminum drum having a diameter of 80 mm to form a 0.5 μm thick intermediate layer.

Next, 20 g of the charge-generating substance used in Example 1 and 10 g of the polyamide of Example 1 as a binder were dissolved in 1000 ml of 1-butanol special grade (manufactured by Kanto Chemical Co., Ltd.), and milled in a ball mill for 24 hours to coat the charge-generating layer. A working liquid was obtained. This was dip-coated on the intermediate layer to form a 0.3 μm thick charge generation layer. The charge transport layer was formed in the same manner as in Example 1,
A photoconductor was obtained by sequentially laminating an intermediate layer, a charge generation layer and a charge transport layer.

Example 13 An intermediate layer was formed in the same manner as in Example 12, and then a charge generation layer was formed in the same manner as in Example 1.

The charge-transporting layer was composed of 120 g of the same charge-transporting substance as in Example 1 and 165 g of polyamide used for the intermediate layer of Example 1 as a binder, n-butyl alcohol special grade (manufactured by Kanto Chemical Co.).
It was dissolved in 1000 ml to obtain a charge transport layer coating solution. This was dip-coated on the charge generation layer and dried at 100 ° C. for 1 hour to prepare a photoreceptor comprising an intermediate layer, a charge generation layer, and a charge transport layer sequentially laminated.

Comparative Example 1 A photoreceptor having a charge generation layer and a charge transport layer sequentially laminated was prepared in exactly the same manner as in Example 1 except that the intermediate layer was not provided.

Comparative Example 2 Nylon 6/66/6/10/12 Copolymer CM8000 (Toray) 3
0 g was added to 800 ml of methanol EL standard (manufactured by Kanto Chemical Co., Ltd.) heated to 50 ° C. with stirring to dissolve. After cooling to room temperature, 200 ml of 1-butanol special grade (Kanto Chemical Co., Ltd.) was added. Thereafter, dip coating was performed on an aluminum drum having a diameter of 80 mm to form an intermediate layer having a thickness of 0.5 μm. The charge generation layer and the charge transport layer were formed in exactly the same manner as in Example 1, and a photoreceptor was prepared by sequentially laminating an intermediate layer, a charge generation layer, and a charge transport layer.

Comparative Example 3 30 g of polyvinyl butyral resin Eslek BH-3 (manufactured by Sekisui Chemical Co., Ltd.) was added with stirring to 800 ml of methanol EL standard (manufactured by Kanto Kagaku Co., Ltd.) with stirring, and then 200 ml of 1-butanol was added. Thereafter, dip coating was performed on an aluminum drum having a diameter of 80 mm to form an intermediate layer having a thickness of 0.5 μm.
The charge generation layer and the charge transport layer were formed in exactly the same manner as in Example 1, and a photoreceptor was prepared by sequentially laminating an intermediate layer, a charge generation layer, and a charge transport layer.

Comparative Example 4 30 g of ethylene-vinyl acetate copolymer Sumitate KA-20 (manufactured by Sumitomo Chemical Co., Ltd.) was poured into an 800 ml methanol EL standard (manufactured by Kanto Kagaku Co., Ltd.) heated to 50 ° C. with stirring to dissolve. After cooling to room temperature, dip coating was performed on an aluminum drum having a diameter of 80 mm to form a 0.5 μm thick intermediate layer. The charge generation layer and the charge transport layer were formed in exactly the same manner as in Example 1, and a photoreceptor was prepared by sequentially laminating an intermediate layer, a charge generation layer, and a charge transport layer.

The photoreceptor prepared as described above is mounted on a modified electrophotographic copier “Konica U-Bix 1550 MR” (manufactured by Konica), and a potential measurement probe model 644 is placed at the position of the developing device.
(Manufactured by Trek) and various properties were measured by the following methods.

(1) Measurement of Charging Rise Characteristics While rotating the photoreceptor at a constant speed, charging and light decay were performed, and the current flowing into the photoreceptor and the charging potential were measured. The charging potential at a photoconductor inflow current of 10 μA is V
The charging potential at ₁₀ (V) and ₂₀ μA was V ₂₀ (V), and the charging potential at ₃₀ μA was V ₃₀ (V).

(2) Sensitivity measurement The exposure amount required to attenuate the surface potential from 600 V to 100 V was defined as ▲ E ⁶⁰⁰ ₁₀₀ lux (lux · sec).

(3) Measurement of DD (Dark Decay Rate) Characteristics The photoreceptor was charged for a certain period of time, and the surface potential was measured 60 seconds after charging was stopped. The dark decay rate was determined by the following equation.

V ₁ = -700V V ₀ = the charged stopped, the measurement photoreceptor surface potential (4) repeating characteristics when after 60 seconds and mounted in a copying machine, performs Stock 50,000 times copying, Stock before and after The surface potential was measured.

Black paper potential Vb: Surface potential with respect to a document having a reflection density of 1.3 White paper potential Vw: Surface potential with respect to a document having a reflection density of 0.0 The image after 50,000 times of actual copying was also evaluated according to the following evaluation criteria.

(Evaluation criteria) ◎ No fogging at a reflection density of 1.3 or more ○ High reflection density △ Fog occurred × Density unevenness The results are shown in Table 1.

As is clear from the results shown in Table 1, the photoreceptor of the present invention has a higher charging potential at the same flowing current value than the photoreceptor of the comparative example, and has excellent charge rising characteristics and good sensitivity. Further, the photoreceptor of the present invention was able to obtain an image without fog at a sufficient density even after performing 50,000 actual copies, but it was not possible to obtain a sufficient density with the photoreceptor of the comparative example, No satisfactory results could be obtained due to fogging or the like.

Incidentally, the dark decay rate (DD (%)) of the example did not change much before actual shooting and after 50,000 times of actual copying, and it was found that a very stable blocking property was maintained.

From the above results, it was found that the polyamide used in the present invention was a resin having a very high blocking property capable of suppressing injection of holes from the base.

Next, a photoconductor was prepared using the above polyamide as a binder for the intermediate layer.

Example 14 800 g of the polyamide used in Example 1 was heated to 50 ° C.
The solution was charged and dissolved in methanol EL standard (manufactured by Kanto Chemical Co., Ltd.) while stirring. After cooling to room temperature, 200 ml of 1-butanol special grade (manufactured by Kanto Kagaku) was added. Then 80mm in diameter
By dip coating on an aluminum drum to form a 1 μm thick intermediate layer.

Next, τ-type metal-free phthalocyanine is used as a charge generation material.
40 g of silicone resin "KR-5240" (solid content: 20%) (manufactured by Shin-Etsu Chemical Co., Ltd.) 200 g dissolved in 2000 ml of methyl ethyl ketone EL standard (manufactured by Kanto Kagaku Co., Ltd.) was dispersed in a sand grinder for 4 hours. A coating liquid was obtained. This was applied onto the above-mentioned intermediate layer by dip coating to form a charge generating layer having a thickness of 0.5 μm.

Thereafter, 120 g of a charge transporting substance having the following structural formula and 165 g of a polycarbonate resin Iupilon Z-200 (manufactured by Mitsubishi Gas Chemical Company) are mixed with 1,2-dichloroethane special grade (manufactured by Kanto Chemical Company) 1
000 ml to obtain a charge transport layer coating solution. After dip coating this on the charge generation layer, drying was performed at 100 ° C. for 1 hour to obtain a charge transport layer having a thickness of 20 μm. A photoreceptor was formed by laminating an intermediate layer, a charge generation layer and a charge transport layer in this order.

Example 15 A photoconductor was prepared by sequentially laminating an intermediate layer, a charge generation layer and a charge transport layer in the same manner as in Example 14 except that X-type metal-free phthalocyanine was used as the charge generation material.

Example 16 A photoconductor was prepared by sequentially stacking an intermediate layer, a charge generation layer and a charge transport layer in the same manner as in Example 14, except that Y-type oxytitanium phthalocyanine was used as the charge generation material.

Example 17 15 g of a fluorenylidene disazo pigment (Exemplified Compound III-7) was used as a charge generating material in a butyral resin “ESLEK BH-
3 "(manufactured by Sekisui Chemical Co., Ltd.) dissolved in 5 g of a methyl ethyl ketone solution EL standard (manufactured by Kanto Kagaku Co., Ltd.) in 1000 ml, and dispersed in a ball mill for 12 hours. In the same manner, a photoconductor was prepared by sequentially laminating an intermediate layer, a charge generation layer and a charge transport layer.

Example 5 A photoconductor was prepared by laminating a charge generation layer and a charge transport layer sequentially in the same manner as in Example 14 except that the intermediate layer was not provided.

Comparative Example 6 In the same manner as in Example 14, except that the binder of the intermediate layer was changed from the polyamide according to the present invention to the polyvinyl butyral resin "ESREC BM-S", the intermediate layer-charge generation layer-charge transport was performed. A photoconductor was prepared by sequentially laminating the layers.

Comparative Example 7 The intermediate layer-charge generation layer- was prepared in exactly the same manner as in Example 16 except that the polyvinyl butyral resin "Eslec BM-S" was used instead of the polyamide according to the present invention as the binder for the intermediate layer. A photoreceptor was formed by sequentially laminating the charge transport layers.

Photoconductors of Examples 14 to 17 and Comparative Examples 5 to 7
U-Bix1550 (Konica)
(Equipped with a semiconductor laser light source) Equipped with a modified machine, _VH is -70
Adjust the grid voltage so that it becomes 0 ± 10 [V], 0.7mW
_VL is the potential of the exposed surface at the time of irradiation of
Performs inversion motion [V], were evaluated black spots white portion of the copied image (-V _H ^5000, potential after copying 5,000 times -V _L ^5000, respectively).

The evaluation of black spots was performed using the image
The shape and the number of black spots were measured using a “type” (manufactured by Shimadzu Corporation), and the number of black spots having a φ (diameter) of 0.05 mm or more was determined based on the number of black spots per cm ² . The criteria for the black spot evaluation are as shown in the following table.

When the result of the black spot determination is ◎ or ○, it is practical, but Δ is not suitable for practical use, and when it is ×, it is not practical.

In order to check the solvent resistance of the intermediate layer,
After drying, it was immersed in methyl ethyl ketone, which is a solvent for the charge generation layer, for 30 seconds, and then observed with an electron microscope (SEM).中間 indicates that the intermediate layer on the immersion surface remained homogeneous, and △ or × indicates that the layer was heterogeneous or had solvent or peeling.

Table 2 shows the evaluation results of the examples and the comparative examples. According to this result, by providing the undercoat layer according to the present invention, the electrophotographic characteristics such as charging, sensitivity, and repeated potential stability are maintained well, and no black spots (that is, the intermediate layer It is possible to obtain a photoreceptor having excellent homogeneity.

Conversely, when the undercoat layer is not provided as in Comparative Example (5), black spots frequently occur, and when a comparative binder as in Comparative Examples (6) to (7) is used, the solvent resistance of the intermediate layer is reduced. Black spots cannot be prevented due to insufficient properties.

[Brief description of the drawings]

1 to 4 are cross-sectional views each showing the layer structure of the electrophotographic photosensitive member. DESCRIPTION OF SYMBOLS 1 ... Support (substrate) 4 ... Charge transport layer 6 ... Charge generation layer 7 ... Intermediate layer 8 ... Photosensitive layer

Continuation of the front page (56) References JP-A-58-30757 (JP, A) JP-A-52-7242 (JP, A) JP-A-50-81910 (JP, A) JP-A-60-227264 (JP, A) , A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 5/00-5/16

Claims (9)

(57) [Claims] 1. An electrophotographic photosensitive member comprising at least a substrate, an intermediate layer and a photosensitive layer, wherein at least one of the intermediate layer and the photosensitive layer comprises an aliphatic aminocarboxylic acid (a component), an aliphatic dicarboxylic acid (b component) and It is derived from an amine having a piperazine ring represented by the following general formula (component c), and the ratio of the components a, b and c is a: b: c = 0.6.
An electrophotographic photoreceptor comprising a polyamide having a viscosity of from 10.0 to 1.0: 0.5 to 1.0. [Wherein R ₁ , R ₂ and R ₃ are each a hydrogen atom or CH ₂ ) _m NH ₂
Represents Here, m represents an integer of 0 to 20. ] 2. The method according to claim 1, wherein said aliphatic aminocarboxylic acid (component a) has an integer of 4 to 12 carbon atoms, and said aliphatic dicarboxylic acid (component b) has an integer of 4 to 12 carbon atoms. The electrophotographic photosensitive member according to claim 1, wherein 3. An intermediate layer comprising the polyamide, wherein the photosensitive layer comprises at least a charge generation layer and a charge transport layer,
3. The electrophotographic photoconductor according to claim 1, wherein the charge generation layer contains a fluorenone-based disazo pigment. 4. The electrophotographic photosensitive material according to claim 1, wherein said photosensitive layer comprises at least a charge generation layer and a charge transport layer, and said charge generation layer contains said polyamide and a fluorenone-based disazo pigment. body. 5. The photosensitive layer comprises at least a charge generation layer and a charge transport layer, wherein the polyamide is contained in the charge transport layer, and the charge generation layer contains a fluorenone-based disazo pigment. 3. The electrophotographic photosensitive member according to 1 or 2. 6. An electrophotographic photoconductor according to claim 3, wherein the electrophotographic photoconductor contains a polycyclic quinone pigment instead of the fluorenone-based disazo pigment. 7. The electrophotographic photoreceptor according to claim 3, further comprising a fluorenylidene-based disazo pigment instead of the fluorenone-based disazo pigment. 8. An electrophotographic photoreceptor according to claim 3, further comprising a metal-free phthalocyanine-based pigment instead of the fluorenone-based disazo pigment. 9. The electrophotographic photoreceptor according to claim 3, wherein an oxytitanyl phthalocyanine pigment is contained in place of the fluorenone-based disazo pigment.