JPH05142811A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide a photosensitive body having improved stability against light and ozone and high sensitivity by forming a photosensitive layer containing a specific stabilizing agent. CONSTITUTION:A photosensitive layer containing at least one kind of salts expressed respectively by formulas I, II, III as a stabilizing agent is formed on a conductive base body. In the formulas, R<1>-R<4> may be the same or different and represent hydrogen atom, alkyl group, aryl group, aralkyl group and X an anion. Each of the salts expressed by the formulas causes a chain reaction due to an active singlet state oxygen or oxygen in a ground state which acts as an oxidizer and thus an electric charge generating material is prevented from being deteriorated. Consequently, in the case where especially an azo compound or a perylene compound is used as an electric charge generating material for a photosensitive body, the decrease of surfacial potential of the photosensitive body can be prevented even if it is used repeatedly and it is possible to stably keep high sensitivity against exposure for a long period and exposure under high temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor used in electrostatic copying machines, laser printers, etc., and more specifically, it contains a specific stabilizer in the photosensitive layer to improve the stability. The present invention relates to the electrophotographic photosensitive member.

[0002]

2. Description of the Related Art In recent years, organic photoconductors are widely used as photoconductors in image forming apparatuses such as copying machines because they are excellent in processability and economy and have a high degree of freedom in functional design. The Carlson process is widely used to form a copied image using a photoconductor. The Carlson process is a charging process that uniformly charges a photoconductor by corona discharge, an exposure process that exposes a document image on the charged photoconductor to form an electrostatic latent image corresponding to the document image, and a developing process that contains toner. On the photoconductor after the transfer step, a development step of developing the electrostatic latent image with a developer to form a toner image, a transfer step of transferring the toner image onto paper, a fixing step of fixing the transferred toner image. And a cleaning step for removing the residual toner. In order to form a high-quality image in the Carlson process, the photoconductor is required to have excellent charging properties and photosensitivity, and to have a low residual potential after exposure.

Conventionally, inorganic photoconductors such as selenium and cadmium sulfide have been known as photosensitive materials, but they have the drawbacks of toxicity and high production cost. Therefore, so-called organic photoconductors using various organic substances in place of these inorganic substances have been proposed. Such an organophotoreceptor has a photosensitive layer composed of a charge generating material that generates a charge upon exposure and a charge transporting material that has a function of transporting the generated charge. In order to satisfy various conditions desired for the organic photoreceptor, it is necessary to appropriately select these charge generating material and charge transporting material. As the charge generating material, an azo compound, a perylene compound, a phthalocyanine compound, a quinacridone compound,
Many compounds such as anthanthrone compounds have been proposed.

Further, in an image forming apparatus or the like, charging,
Stabilizers such as antioxidants and light stabilizers are applied to the photosensitive layer so that the photosensitive layer does not fatigue and the charging characteristics and the photosensitive characteristics are deteriorated during repeated image forming processes such as exposure and charge removal. Is being added. As the stabilizer for the photoconductor, not only the stabilizing effect but also the photosensitivity is not required to be adversely affected, and various stabilizers having these properties to some extent have been proposed. For example,
As antioxidants, hindered phenols, paraphenylenediamines, hydroquinones, organic sulfur compounds, organic phosphorus compounds, etc. have been proposed.

[0005]

However, none of the above stabilizers is sufficient to impart oxidation resistance and light stability of the photosensitive layer, and as a result, maintain the photosensitive characteristics of the photoreceptor. There was a problem that I could not. Further, all of the above conventional charge generating materials have poor charging characteristics, photosensitive characteristics, etc. during repeated use, and the photoreceptors using these charge generating materials have insufficient sensitivity and durability. There was a problem of becoming.

In particular, in the photoconductor using an azo compound or a perylene compound as the charge generating material, these charge generating materials are easily deteriorated by light or ozone during the operation of the image forming apparatus, and the surface potential Cause deterioration. Therefore, an object of the present invention is to provide a highly sensitive electrophotographic photosensitive member having improved stability against light and ozone.

[0007]

The electrophotographic photosensitive member of the present invention comprises a salt represented by the following general formulas (Ia), (Ib) and (Ic) as a stabilizer on a conductive substrate. And a photosensitive layer containing at least one of the above.

[0008]

[Chemical 2]

[Wherein R ¹ , R ² , R ³ and R ⁴ are
The same or different, a hydrogen atom, an alkyl group, an aryl group or an aralkyl group is shown, and X is an anion. The salts represented by the above general formulas (Ia), (Ib) and (Ic) are all singlet oxygen ( ¹ O ₂ ) of active species or oxygen in the ground state (as a biradical (.OO)). It is possible to prevent the charge-generating material from being deteriorated by causing a chain reaction to occur due to (having reactivity) acting as an oxidizing agent.

For example, when an azo compound is used as the charge generating material, the equilibrium between the azo type and the hydrazone type significantly affects the photostability of the photoconductor, but the above general formula (Ia), ( The salt represented by Ib) or (Ic) can prevent the photobleaching product from being isolated from the hydrazone form by the nin type reaction of singlet oxygen. That is, the general formula
The salt represented by (Ia), (Ib) or (Ic) can quench singlet oxygen or the like serving as an oxidizing agent. Above all, it is possible to prevent the deterioration of the azo compound or the perylene compound.

For this reason, a photoreceptor using an azo compound or a perylene compound as a charge generating material is
The surface potential can be prevented from lowering even after repeated use, and it is possible to stably maintain high sensitivity even for long-term exposure or exposure at high temperature, and to obtain a product with excellent light stability. .. Examples of the alkyl group include a methyl group,
Examples thereof include alkyl groups having 1 to 6 carbon atoms such as ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group and hexyl group.

As the aryl group, for example, a phenyl group,
Examples thereof include a tolyl group, a xylyl group, a biphenyl group, a naphthyl group, an anthryl group and a phenanthryl group. Examples of the aralkyl group include an aralkyl group having 1 to 6 carbon atoms in the alkyl moiety such as a benzyl group, an α-phenethyl group, a β-phenethyl group, a 3-phenylpropyl group, a benzhydryl group and a trityl group.

As the anion represented by X, for example,
Halogen atom, halogenated oxygen, hydrohalic acid, etc.
Anion can be mentioned, and specifically Cl^-, F^-, B
r^-, I ^-, ClO_Four ^-, SbF₆ ^-Etc.
It The salt represented by the above general formula (Ia), (Ib) or (Ic)
Can be synthesized by a conventionally known method.
It Specific examples of salts represented by general formula (Ia), (Ib) or (Ic)
Examples include compounds represented by the following formulas (1) to (6)
I can show you.

[0014]

[Chemical 3]

[0015]

[Chemical 4]

The salts represented by the above general formulas (Ia), (Ib) and (Ic) used as stabilizers for the photoconductor can be used alone or in admixture, and their additions can be made. Suitably the amount is in the ratio of about 0.05 to 150 parts with respect to the charge generating material. When the blending ratio of the salt exceeds 150 parts, the salt inhibits the generation of electric charges, and conversely, when the blending ratio is less than 0.05 part, the quenching action of singlet oxygen and the like by the salt is insufficient. become.

In the organic photosensitive layer, the above-mentioned general formula (Ia),
In addition to the salt represented by (Ib) or (Ic), additives such as a sensitizer, a fluorene compound, an antioxidant, a deterioration inhibitor such as an ultraviolet absorber and a plasticizer can be contained. Further, in order to improve the sensitivity of the charge generation layer, known sensitizers such as terphenyl, halonaphthoquinones and acenaphthylene may be used in combination with the charge generation material.

The constitution of the present invention can be applied to both so-called single-layer type and laminated type electrophotographic photoconductors. In order to obtain a single-layer type photoreceptor, at least one of the salts represented by the above general formulas (Ia), (Ib) and (Ic) as a stabilizer is used.
A photosensitive layer containing a seed, a charge generating material, a charge transporting material, a binder resin and the like may be formed on the conductive substrate by means of coating or the like.

In order to obtain a laminated type photoreceptor, at least one of the salts represented by the above general formulas (Ia), (Ib) and (Ic) is applied on a conductive substrate by means such as coating. A charge generation layer containing a charge generation material may be formed, and a charge transport layer containing a charge transport material and a binder resin may be formed on the charge generation layer. Alternatively, contrary to the above, a charge transport layer similar to the above may be formed on the conductive substrate, and then a charge generating layer similar to the above may be formed by means such as coating. Further, the charge generation layer may be formed by dispersing and applying a charge generation material and a charge transport material in a binder resin.

As the charge generating material, an azo compound or a perylene compound is preferably used. The azo compound, for example, the following general formula (a1) ~ (a15)
The compound represented by

[0021]

[Chemical 5]

[0022]

[Chemical 6]

[In the formula, R ⁵ represents an alkyl group or an aryl group which may have a substituent, and Y ¹ and Y
² is the same or different and represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or an alkoxy group, and A represents a coupler residue. ]

[0024]

[Chemical 7]

[In the formula, Y ¹ , Y ² and Y ³ are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an alkyl group or an alkoxy group, and A is the same as defined above. ]

[0026]

[Chemical 8]

[In the formula, R ⁶ represents a hydrogen atom which may have a substituent, a halogen atom, an alkyl group or a cyano group, D represents an oxygen atom, a sulfur atom or an imino group,
m represents an integer of 0 or 1, and A is the same as above. ]

[0028]

[Chemical 9]

[In the formula, Y ¹ and Y ² are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group or an alkyl group which may have a substituent, and A is the same as defined above. ]

[0030]

[Chemical 10]

[In the formula, R ⁷ represents an alkyl group which may have a hydrogen substituent, an aryl group which may have a substituent or a heterocyclic group, and m and A are the same as the above]

[0032]

[Chemical 11]

[In the formula, R ⁸ and R ⁹ are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an optionally substituted alkyl group, an aryl group or an alkoxy group, and D and A are the same as those described above. Is the same as. ]

[0034]

[Chemical 12]

[In the formula, R ¹⁰ and R ¹¹ are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, an optionally substituted alkyl group, an aryl group or an alkoxy group, and A is the same as above. Is. ]

[0036]

[Chemical 13]

[In the formula, R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group, and A is the same as defined above. is there. ]

[0038]

[Chemical 14]

[In the formula, R ¹⁸ and R ¹⁹ are the same or different and each represents a hydrogen atom, a halogen atom, a cyano group, a nitro group,
It represents an alkyl group, an aryl group or an alkoxy group which may have a substituent, Ar represents an aryl group which may have a substituent, n represents 0 or 1, and A is the same as defined above. ]

[0040]

[Chemical 15]

[Wherein R ²⁰ , R ²¹ , R ²² and R ²³ are
The same or different, it shows a hydrogen atom, a halogen atom, an alkyl group, an aryl group, or an alkoxy group, and A is the same as the above. ]

[0042]

[Chemical 16]

[In the formula, R ²⁴ and R ²⁵ are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group or an alkoxy group, and D and A are the same as defined above. In each of the above formulas, examples of the aryl group include the same groups as described above, and examples of the alkyl group include, in addition to the above groups,
Octyl group, tert-octyl group, decyl group, hexadecyl group, dodecyl group, 2-hydroxyethyl group, carboxymethyl group, cyanomethyl group, 2-methoxyethyl group,
Benzyl group, 2-phenylmethyl group, trifluoromethyl group, hydroxymethyl group, methoxymethyl group, dicyanomethyl group, aminomethyl group, N-methylaminomethyl group, mercaptomethyl group, methylthiomethyl group, N, N
-Dimethylaminomethyl group, chloromethyl group, bromomethyl group and the like.

Examples of the alkoxy group which may have a substituent include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group,
tert-butoxy group, pentyloxy group, hexyloxy group, heptyloxy group, octyloxy group, nonyloxy group, 2-hydroxyethoxy group, carboxymethoxy group, cyanomethoxy group, 2-methoxyethoxy group, benzyloxy group, 2 -Methylphenoxy group, trifluoromethoxy group, hydroxymethoxy group, methoxymethoxy group, dicyanomethoxy group, aminomethoxy group, N-methylaminomethoxy group, mercaptomethoxy group, methylthiomethoxy group, N, N-dimethylaminomethoxy group , Chloromethoxy group, bromomethoxy group and the like.

As the heterocyclic group, for example, a thienyl group,
Pyrrolyl group, pyrrolidinyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, imidazolyl group, 2H-imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, pyranyl group, pyridyl group, piperidyl group, piperidino group, 3-morpholinyl group Group, morpholino group and the like.

Examples of the coupler residue represented by A include groups represented by the following general formulas (a) to (g).

[0047]

[Chemical 17]

In each formula, R ⁴ represents a carbamoyl group, a sulfamoyl group, an allofanoyl group, an oxamoyl group, an anthraniloyl group, a carbazoyl group, a glycyl group, a hydantoyl group, a phthalamoyl group, and a succinamoyl group. These groups include a halogen atom, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a nitro group, a cyano group, an alkyl group, an alkenyl group, a carbonyl group, a carboxyl group and the like. It may have a substituent.

R ⁵ represents an atomic group necessary for forming an aromatic ring, a polycyclic hydrocarbon or a heterocyclic ring by condensing with R ⁴ and the benzene ring having a hydroxyl group, and these rings are as described above. You may have the same substituent. R ⁶ represents an oxygen atom, a sulfur atom or an imino group. R ⁷ represents a divalent chain hydrocarbon or aromatic hydrocarbon, and these groups may have the same substituents as described above.

R ⁸ represents an alkyl group, an aralkyl group, an aryl group or a heterocyclic group, and these groups may have the same substituents as described above. R ⁹ is a divalent chain hydrocarbon, an aromatic hydrocarbon, or the following formula (h) in the general formulas (e) and (f):

[0051]

[Chemical 18]

It represents an atomic group necessary for forming a heterocycle with the moiety represented by, and these rings may have the same substituents as described above. R ¹⁰ is a hydrogen atom, an alkyl group,
It represents an amino group, a carbamoyl group, a sulfamoyl group, an allofanoyl group, a carboxyl group, an ester of a carboxyl group, an aryl group or a cyano group, and groups other than a hydrogen atom may have the same substituents as described above.

R ¹¹ represents an alkyl group or an aryl group, and these groups may have the same substituents as described above.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group and a te group.
rt-butyl group, pentyl group, hexyl group, etc., having 1 carbon atom
The lower alkyl groups of 6 are mentioned.

As the aryl group, for example, a phenyl group,
Examples thereof include a tolyl group, a xylyl group, a biphenyl group, a naphthyl group, an anthryl group and a phenanthryl group. As the alkenyl group, for example, vinyl group, allyl group, 2-butenyl group, 3-butenyl group, 1-methylallyl group, 2-
Examples thereof include lower alkenyl groups having 2 to 6 carbon atoms such as pentenyl group and 2-hexenyl group.

Examples of the halogen atom include chlorine atom, bromine atom, iodine atom and fluorine atom. In R ⁵ , the atomic group necessary for forming an aromatic ring by condensing with R ⁴ and a benzene ring having a hydroxyl group is, for example, an alkylene group such as a methylene group, an ethylene group, a propylene group or a butylene group. Be done.

The aromatic ring formed by the condensation of R ⁵ with R ⁴ and a benzene ring having a hydroxyl group is
Examples thereof include naphthalene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, and naphthacene ring. In R ⁵ , the atomic group necessary for condensation with R ⁴ and a benzene ring having a hydroxyl group to form a polycyclic hydrocarbon is, for example, a carbon atom such as a methylene group, an ethylene group, a propylene group, a butylene group or the like. Examples include alkylene groups of the numbers 1 to 4.

The polycyclic hydrocarbon formed by the condensation of R ⁵ with R ⁴ and a benzene ring having a hydroxyl group includes, for example, a carbazole ring, a benzocarbazole ring,
Examples include a dibenzofuran ring. Further, in R ⁵ , as the atomic group necessary for forming a heterocycle by being condensed with R ⁴ and a benzene ring having a hydroxyl group, for example, a benzofuranyl group, a benzothiophenyl group, an indolyl group,
1H-indolyl group, bezoxazolyl group, benzothiazolyl group, 1H-indaryl group, benzimidazolyl group, chromenyl group, chromanyl group, isochromanyl group,
Quinolinyl group, isoquinolinyl group, cinnolinyl group, phthalazinyl group, quinazonilyl group, quinoxalinyl group, dibenzofuranyl group, carbazolyl group, xanthenyl group,
Examples thereof include an acridinyl group, a phenanthridinyl group, a phenazinyl group, a phenoxazinyl group and a thianthrenyl group.

Examples of the aromatic heterocyclic group formed by the condensation of R ⁵ with R ⁴ and a benzene ring having a hydroxyl group include, for example, thienyl group, furyl group, pyrrolyl group, oxazolyl group, isoxazolyl group and thiazolyl group. , Isothiazolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, pyridyl group and thiazolyl group. In addition, it may be a heterocyclic group condensed with another aromatic ring (for example, a benzofuranyl group, a benzimidazolyl group, a benzoxazolyl group, a benzothiazolyl group, a quinolyl group).

In the above R ⁷ and R ⁹ , examples of the divalent chain hydrocarbon include ethylene group, propylene group and butylene group, and examples of the divalent aromatic hydrocarbon include phenylene group, naphthylene group, Examples thereof include a phenanthrylene group. Examples of the heterocyclic group for R ⁸ include a pyridyl group, a pyrazyl group, a thienyl group, a pyranyl group and an indolyl group.

In R ⁹ , the atomic group necessary for forming a heterocycle with the moiety represented by the formula (h) is, for example, phenylene group, naphthylene group, phenanthrylene group, ethylene group, propylene group or butylene. Examples include groups. Examples of the aromatic heterocyclic group formed by R ⁹ and the moiety represented by the formula (h) include, for example, benzimidazole group, benzo [f] benzimidazole group, dibenzo [e, g] benzimidazole group. Group, benzopyrimidine group and the like. These groups may have the same substituents as described above.

Examples of the carboxyl group ester represented by R ¹⁰ include methyl ester, ethyl ester, propyl ester and butyl ester. Specific examples of the coupler residue A represented by the above general formulas (a) to (g) include the following groups.

[0062]

[Chemical 19]

[0063]

[Chemical 20]

[0064]

[Chemical 21]

[0065]

[Chemical formula 22]

Specific examples of the azo compounds include compounds represented by the following formulas (b1) to (b12).

[0067]

[Chemical formula 23]

[0068]

[Chemical formula 24]

[0069]

[Chemical 25]

[0070]

[Chemical formula 26]

Further, specific examples of the perylene compound include compounds represented by the following formulas (c1) to (c7).

[0072]

[Chemical 27]

[0073]

[Chemical 28]

[0074]

[Chemical 29]

In the electrophotographic photoreceptor of the present invention, the salt represented by the general formula (I) as a stabilizer and the azo compound or the perylene compound as a charge generating material are used alone. Besides, it can be used in combination with a conventionally known charge generating material. Examples of other charge generating materials include amorphous silicon, anthanthrone pigment, phthalocyanine pigment, indigo pigment, triphenylmethane pigment, slene pigment, toluidine pigment, pyrazoline pigment, quinacridone pigment, and the like. Be done. These charge generating materials are used alone or in combination of two or more so as to have an absorption wavelength region in a desired region.

As the charge transporting material, conventionally known materials can be used, for example, oxadiazole compounds such as 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole, Styryl compounds such as 9- (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, triphenylamine Compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, nitrogen-containing cyclic compounds such as triazole compounds, and condensed polycyclic compounds. Be done. These charge transport materials are used alone or in combination of two or more. Note that the binder resin is not always necessary when using a charge transporting material having film-forming properties such as polyvinylcarbazole.

Various resins can be used as the binder resin used in the above-mentioned single-layer type or multi-layer type photoreceptors. For example, a styrene-based polymer, a styrene-butadiene copolymer, a styrene- Acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic polymer, styrene-acrylic copolymer, polyethylene, ethylene vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate Thermoplastic resin such as copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, silicone resin, epoxy resin, phenol resin, Urea resin, Min resin, other crosslinking thermosetting resin, further epoxy acrylates, urethane - various polymers, such as photo-curable resin such as acrylate. These binder resins may be used alone or in combination of two or more.

A solvent is used when the charge generation layer and the charge transport layer are formed by a coating method or the like. As this solvent, various organic solvents can be used, for example, alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, benzene, toluene, Aromatic hydrocarbons such as xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone and cyclohexanone. Examples thereof include various solvents such as compounds, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide, dimethylsulfoxide, and the like. These solvents may be used alone or in combination of two or more.

Further, a surfactant, a leveling agent or the like may be used in order to improve the dispersibility, dyeing property and the like of the charge generating material and the charge transporting material. Various materials having conductivity can be used as the conductive substrate. For example, a simple substance of metal such as aluminum, copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, or brass, or a plastic material in which the above metal is vapor-deposited or laminated. , Glass coated with aluminum iodide, tin oxide, indium oxide and the like.

The conductive substrate may be in the form of a sheet or a drum, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. As the substrate, a substrate having sufficient mechanical strength when used is preferable. The addition amount of the charge generating material in the single-layer type photosensitive layer is 0.1 to 50 parts by weight based on 100 parts by weight of the binder resin.
Suitably, it is 0.5 to 30 parts by weight. The addition amount of the charge transport material in the single-layer type photosensitive layer is 40 to 200 with respect to 100 parts by weight of the binder resin.
Suitably, parts by weight, preferably 50 to 150 parts by weight.

The amount of the charge transport material added to the laminated charge transport layer is 10 to 100 parts by weight of the binder resin.
Suitably 500 parts by weight, preferably 25 to 200 parts by weight. The amount of the charge generating material added to the laminated charge generating layer is appropriately 5 to 500 parts by weight, preferably 10 to 300 parts by weight, based on 100 parts by weight of the binder resin.

The film thickness of the photosensitive layer formed is preferably about 5 to 100 μm, and more preferably about 15 to 25 μm in the case of a single layer type. In the case of a laminated type, the thickness of the charge generation layer is preferably about 0.01 to 5 μm, particularly about 0.1 to 3 μm, and the thickness of the charge transport layer is about 2 to 100 μm, particularly about 5 to 50 μm. Is preferred.

When the charge generation layer and the charge transport layer are formed by a coating method, the charge generation material and the binder resin may be formed by a known method such as roll mill, ball mill, attritor, paint shaker or ultrasonic wave. It may be prepared by dispersing and mixing using a disperser or the like, and applying and drying this by a known means. Further, the charge generation layer may be formed by depositing the above charge generation material.

In the case of the single-layer type electrophotographic photosensitive member, between the conductive substrate and the photosensitive layer, and in the laminated type electrophotographic photosensitive member, the conductive substrate and the charge generating layer are provided. A barrier layer may be formed between the electrically conductive substrate and the charge transport layer and between the charge generation layer and the charge transport layer as long as the characteristics of the photoreceptor are not impaired. A protective layer may be formed on the surface of the photoconductor.

[0085]

The present invention will be described in detail below with reference to examples and comparative examples. Example 1 0.05 part of the salt represented by the above formula (1) as a stabilizer, 10 parts of the azo pigment represented by the above formula (b1) as a charge generating material, and the following as a charge transport material: 80 parts of DEH represented by the formula (B), 100 parts of polycarbonate as a binder resin, and a predetermined amount of methylene chloride as a solvent are mixed and dispersed using a paint shaker to prepare a single-layer type photosensitive layer coating liquid. Was adjusted.

[0086]

[Chemical 30]

This coating solution was applied to the surface of an aluminum foil using a wire bar, and a sheet-shaped product having an outer diameter of 78
mm-230 mm long aluminum tube with a drum-shaped coating applied by dipping on the surface at 60 ° C in the dark
And heated and dried for 120 minutes to prepare a positively charged electrophotographic photosensitive member having a single-layer type photosensitive layer each having a film thickness of 18 μm.

Example 2 The above Example except that the stabilizer used in Example 1 was changed to 1.5 parts and the charge generating material was used in place of the azo pigment represented by the formula (b2). A single layer type photoreceptor was prepared in the same manner as in 1. Example 3 The same procedure as in Example 1 was repeated except that 10 parts of the stabilizer used in Example 1 was used and the charge generating material was used instead of the azo pigment represented by the formula (b3). A single-layer type photoconductor was prepared.

Example 4 Instead of the stabilizer and the charge generating material used in Example 1, 20 parts of the salt represented by the formula (2) and the azo pigment represented by the formula (b4) were used. Example 1 above, except that it was used
A single-layer type photoreceptor was prepared in the same manner as in. Example 5 Instead of the stabilizer and the charge generating material used in Example 1, 30 parts of the salt represented by the formula (2) and the azo pigment represented by the formula (b5) were used. Example 1 except the above
A single-layer type photoreceptor was prepared in the same manner as in.

Example 6 In place of the stabilizer and the charge generating material used in Example 1, 50 parts of the salt represented by the formula (3) and the azo pigment represented by the formula (b6) were used. Example 1 above, except that it was used
A single-layer type photoreceptor was prepared in the same manner as in. Example 7 In place of the stabilizer and the charge generating material used in Example 1, 1.5 parts of the salt represented by the above formula (4) and the above formula (b7)
A single-layer type photoreceptor was produced in the same manner as in Example 1 except that the azo pigment represented by

Example 8 Instead of the stabilizer and the charge generating material used in Example 1, 2 parts of the salt represented by the formula (5) and the azo pigment represented by the formula (b9) were used. A single-layer type photoreceptor was produced in the same manner as in Example 1 except that it was used. Example 9 Instead of the charge generating material used in Example 1, the above formula (c2) was used.
A single-layer type photoreceptor was produced in the same manner as in Example 1 except that the perylene compound represented by

Example 10 Instead of the stabilizer and the charge generating material used in Example 1, a salt represented by the above formula (2) and a perylene compound represented by the above formula (c4) were used. Other than the above, Example 1 above
A single-layer type photoreceptor was prepared in the same manner as in. Example 11 Except that the salt represented by the formula (6) and the perylene-based compound represented by the formula (c6) were used in place of the stabilizer and the charge generating material used in Example 1. Example 1 above
A single-layer type photoreceptor was prepared in the same manner as in.

Comparative Examples 1 to 11 The above formula (b1) which is a charge generating material is used without using a stabilizer.
~ (B7), the azo pigment represented by (b9) and the formula (c2), (c
A single-layer type photoreceptor was prepared in the same manner as in Example 1 except that the perylene compounds represented by 4) and (c6) were used. The following tests were carried out on the electrophotographic photosensitive members obtained in the above-mentioned respective Examples and Comparative Examples to evaluate their characteristics.

Measurement of initial surface potential Electrostatic copying tester (EPA-810 manufactured by Kawaguchi Electric Co., Ltd.)
0) is used to apply a voltage to each electrophotographic photosensitive member to positively charge its surface, and the initial surface potential Vs.p.
(V) was measured. Measurement of half-dose exposure and residual potential The electrophotographic photoreceptor charged in the above-mentioned measurement of the initial surface potential was exposed under a condition of exposure intensity of 10 lux by using a white halogen lamp which is an exposure light source of an electrostatic copying tester. The half-exposure amount E1 / 2 (lux.sec) was calculated by obtaining the time required for the surface potential to become 1/2 after the exposure.

The surface potential was measured 5 seconds after the start of the exposure, and the residual potential Vr.p. (V) was measured. Measurement of Light Stability The above drum-shaped electrophotographic photosensitive member was loaded in an electrostatic copying machine (Model No. DC-111 manufactured by Mita Kogyo Co., Ltd.) to perform continuous copying of 1000 sheets, and then, in the same manner as above. The initial surface potential V1s.p. (V) after repeated exposure was measured. Then, the difference ΔVs.p. (V) from the surface potential Vs.p.

The above results are shown in Table 1. The stabilizers and charge generation materials used are indicated by the numbers in the above formula.

[0097]

[Table 1]

From the results shown in Table 1 above, the electrophotographic photoreceptors of Examples 1 to 8 having the constitution of the present invention have a surface potential [Vs.
p.], half exposure [E1 / 2] and residual potential [Vr.p.]
There is almost no difference with respect to the conventional photoconductors of Comparative Examples 1 to 8, but the light stability [ΔVs.p.] is smaller than that of the photoconductors of Comparative Examples, so that they can be used repeatedly. It was found that the surface potential change of the photoconductor was small, and all of them had excellent durability.

[0099]

As described above, the electrophotographic photoreceptor of the present invention has a high sensitivity because it contains a stabilizer capable of preventing deterioration due to light or ozone in the photosensitive layer. ,
Moreover, a product having excellent durability can be obtained.

Claims (1)

[Claims] 1. A photosensitive layer comprising, on a conductive substrate, a photosensitive layer containing, as a stabilizer, at least one of the salts represented by the following general formulas (Ia), (Ib) and (Ic), respectively. And an electrophotographic photoreceptor. [Chemical 1] [In the formula, R ¹ , R ² , R ³ and R ⁴ are the same or different and each represents a hydrogen atom, an alkyl group, an aryl group or an aralkyl group, and X represents an anion. ]