JPH07146573A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic photoreceptor excellent in repetitive characteristics by incorporating a specified pyridine compd. into a photosensitive layer. CONSTITUTION:A photosensitive layer contg. an electric charge generating material, an electric charge transferring material and a pyridine compd. represented by the formula is formed on an electric conductive substrate to obtain the objective electrophotographic photoreceptor. In the formula, R1 is H, halogen, 1-10C alkyl which may have one or more substituents, alkoxy, aryl or aralkyl.

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 an image forming apparatus utilizing electrophotography such as an electrostatic copying machine and a laser beam printer.

[0002]

2. Description of the Related Art An electrophotographic method such as the Carlson process includes the following steps. That is, the step of uniformly charging the surface of the electrophotographic photosensitive member by corona discharge, the exposure step of exposing the charged surface of the electrophotographic photosensitive member to form an electrostatic latent image on the surface of the photosensitive member, the formation A developing step of bringing a developer into contact with the formed electrostatic latent image, and developing the electrostatic latent image into a toner image by toner contained in the developer; a transfer step of transferring the toner image to paper or the like; It includes a fixing step of fixing the transferred toner image, and a cleaning step of removing the toner remaining on the photoconductor after the transfer step.

Organic photoconductors (OPC), amorphous silicon (a-Si), some selenium photoconductors, etc. are known as electrophotographic photoconductors used in the above electrophotographic method. In many cases, an organic photoconductor is used from a comprehensive viewpoint such as flexibility, processability, and cost.

The organic photoreceptor usually has a photosensitive layer containing a charge generating material which generates charges upon exposure and a charge transporting material which has a function of transporting the generated charges.

The organic photoconductor is repeatedly used in a copying machine and is exposed to ozone and nitrogen oxides (NO _x ) generated by corona discharge in the charging process and to light in the exposure process. These ozone, NO _x ,
By light, the charge-generating material or charge-transporting material in the organic photoreceptor is attacked and causes a chemical reaction to lose its charge-generating ability or charge-transporting ability, or becomes a deep trap that inhibits electrophotographic characteristics. When the substance is changed to a substance, the photoconductor is deteriorated, and there is a drawback that the charging property is lowered, the residual potential is increased, and the sensitivity is deteriorated.

In order to eliminate this drawback from the aspect of the apparatus, a special system such as a special charging system that does not generate ozone or NO _x , a system that decomposes generated ozone, a system that exhausts ozone in the apparatus is required. However, there was a problem that the process and system became complicated.

[0007] Further, as an attempt to eliminate the prescription of the photoreceptor, JP-A-57-122444 and JP-A-61-161
As disclosed in Japanese Patent No. 156052, a proposal has been made to prevent oxidative deterioration of the above materials by adding an antioxidant, but the present situation is that satisfactory results have not yet been obtained.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide an electrophotographic photosensitive member excellent in NO _x resistance and repetitive characteristics.

[0009]

The present inventors have solved the above problems by providing a photosensitive layer containing a charge generating material, a charge transporting material, and a pyridine compound on a conductive substrate. The invention was completed.

That is, the present invention provides a charge generating material, a charge transporting material, and a pyridine compound represented by the following general formula (I):

[0011]

[Chemical 3]

(Here, R ₁ represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms, an alkoxy group, an aryl group, or an aralkyl group, which may have one or more substituents. And a photosensitive layer containing a) is provided on a conductive substrate.

Therefore, according to the present invention, the charge-generating material or the charge-transporting material is not deteriorated by ozone or NO _x generated in the charging device or by being exposed to light in the exposure step, and the charge-generating material or the charge-transporting material is charged even if it is repeatedly used. To provide an electrophotographic photosensitive member that is less likely to deteriorate, increase in residual potential, deterioration of sensitivity, and the like, and to be suitably used for an image forming apparatus such as an electrostatic copying machine or a laser beam printer. The purpose of providing can be achieved.

[0014]

The above electrophotographic photoreceptor can be manufactured by the method described below. First, the operation of the electrophotographic photoreceptor containing the pyridine compound of the present invention will be described.

Although the action of the pyridine compound used in the photoreceptor of the present invention has not been clarified, the pyridine compound of the present invention does not interact with other photoreceptor materials such as charge generating materials and charge transport materials. It is a compound that has a small action and does not adversely affect the electrophotographic properties. In addition, the pyridine compound has an action of competitively reacting with an external attacking object such as light and ozone and suppressing a reaction between the photoconductor constituent material and the external attacking object. It has the effect of deactivating the radical species inside. Since these radical species cause trapping of charges, it is inferred that the pyridine compound has an excellent ability to prevent trap generation. this is,
From the results of Examples described later, by adding a pyridine compound, the decrease in surface potential after 10,000 times of repetition was suppressed, and the deterioration in sensitivity indicated by the half-exposure amount was small. It can be seen that it is effective in improving the sex.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The materials used in the present invention and the production of photoconductors will be described below.

The pyridine compound used in the electrophotographic photoreceptor of the present invention is represented by the following general formula (I).

[0018]

[Chemical 4]

In the above general formula (I), R ₁ is a hydrogen atom, a halogen atom, or an alkyl group having 1 to 10 carbon atoms, an alkoxy group, which may have one or more substituents,
An aryl group or an aralkyl group is shown.

In the pyridine compound represented by the general formula (I), the alkyl group corresponding to R ₁ is, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group or a t-butyl group. Groups, pentyl groups, hexyl groups and the like can be used.

As the alkoxy group corresponding to R ₁ , for example, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, t-butoxy group, hexyloxy group and the like can be used.

Examples of the aryl group corresponding to R ₁ include phenyl group, tolyl group, xylyl group, biphenyl group,
A naphthyl group, an anthryl group, a phenanthryl group and the like can be used.

As the aralkyl group corresponding to R ₁ , for example, a benzyl group, a benzhydryl group, a trityl group, a phenethyl group or the like can be used.

Specific examples of the pyridine compound represented by the above general formula (I) include No. 1 shown in Table 1 below.
1-No. The one shown in 17 can be used.

[0025]

[Table 1]

(Charge Generating Material) As the charge generating material,
Charge generating materials commonly used in the art can be used. For example, selenium, selenium-tellurium, selenium-arsenic,
Amorphous silicon, pyrylium salt, azo pigment, perylene pigment, ansanthuron pigment, phthalocyanine pigment, indigo pigment, triphenylmethane pigment,
Slene pigment, toluidine pigment, pyrazoline pigment,
A quinacridone pigment and a pyrrolopyrrole pigment can be used.

These charge generating materials may be used alone or in combination.
You can use more than one type.

Among these charge generating materials, the above-mentioned azo pigments are especially the ozone and nitrogen oxides N generated in the copying machine.
It is prone to oxidative deterioration due to O _x , light, etc., and the effect of deactivating radical species by the pyridine compound of the present invention is remarkably exhibited.

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

[0030]

[Chemical 5]

[0031]

[Chemical 6]

[0032]

[Chemical 7]

[0033]

[Chemical 8]

Among the above azo pigments, a bisazo pigment represented by the following general formula (II) can be used as a compound having a high charge generation efficiency.

[0035]

[Chemical 9]

In the above general formula (II), A ₁ and A ₂ are respectively independent coupler residues, R ₂ is a hydrogen atom, an alkyl group which may have one or more substituents, an aryl group,
Alternatively, a heterocyclic group, n ₁ represents 0 or 1.

In the bisazo pigment represented by the general formula (II), the alkyl group corresponding to R ₂ is, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group or t-butyl group. An alkyl group having 1 to 6 carbon atoms such as a pentyl group and a hexyl group can be used.

As the aryl group corresponding to R ₂ , for example, a phenyl group, an o-terphenyl group, a naphthyl group, an anthryl group, a phenanthryl group and the like can be used.

Examples of the heterocyclic group corresponding to R ₂ include 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-
A morpholinyl group, a morpholino group, a thiazolyl group and the like can be used. It may also be a heterocyclic group fused with an aromatic ring.

In the alkyl group, the aryl group and the heterocyclic group corresponding to R ₂ , the substitutable group is, for example, a halogen atom, an amino group, a hydroxyl group, an optionally esterified carboxyl group or a cyano group. An alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms which may have an aryl group, and the like can be used.

In the bisazo pigment represented by the general formula (II), examples of the coupler residue represented by A ₁ and A ₂ include groups represented by the following general formulas (a) to (g). .

[0042]

[Chemical 10]

R ³⁰ in the above general formula (a) may be 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, or a succinamoyl group. These groups are a halogen atom, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, an alkyl group, an alkenyl group, a carbonyl group,
It may have a carboxyl group or the like.

R in the above general formulas (a) and (b)
³¹ represents an atomic group necessary for forming an aromatic ring, a polycyclic hydrocarbon, or a heterocycle by condensing with the above R ³⁰ and a benzene ring having a hydroxyl group, and these rings have the same substituents as described above. Can have a group.

R ³² in the general formula (b) represents an oxygen atom, a sulfur atom or an imino group.

R ³³ in the above general formula (b) represents a divalent chain hydrocarbon or aromatic hydrocarbon, and these groups may have the same substituents as described above.

R in the above general formulas (c) and (d)
³⁴ 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 in the above general formulas (e) and (f)
³⁵ is a divalent chain hydrocarbon, aromatic hydrocarbon, or
The following general formula (h):

[0049]

[Chemical 11]

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 ³⁶ in the general formula (g) is a hydrogen atom,
Alkyl group, amino group, carbamoyl group, sulfamoyl group, allofanoyl group, carboxyl group, ester of carboxyl group, aryl group, or cyano group,
The groups other than hydrogen atom may have the same substituents as described above.

R ³⁷ in the general formula (g) represents an alkyl group or an aryl group, and these groups may have the same substituents as described above.

In R ³¹ , the atomic group necessary for condensation with R ³⁰ and a benzene ring having a hydroxyl group to form an aromatic ring is, for example, a methylene group, an ethylene group, a propylene group or a butylene group. Alkylene groups of can be used.

In R ³¹ , the aromatic ring formed by condensation with R ³⁰ and a benzene ring having a hydroxyl group is, for example, a naphthalene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring or naphthacene ring. Can be used.

In R ³¹ , the atomic group necessary for condensation with R ³⁰ and a benzene ring having a hydroxyl group to form a polycyclic hydrocarbon is, for example, a methylene group, an ethylene group, a propylene group or butylene. 1 to 4 carbon atoms such as groups
Alkylene groups of can be used.

In R ³¹ , the polycyclic hydrocarbon formed by condensation with R ³⁰ and a benzene ring having a hydroxyl group may be, for example, a carbazole ring, a benzocarbazole ring or a dibenzofuran ring.

In R ³¹ , the atomic group necessary for condensation with R ³⁰ and a benzene ring having a hydroxyl group to form a heterocyclic group is, for example, benzofuranyl group, benzothiophenyl group, indolyl group, 1H -Indolyl group, benzoxazolyl group, benzothiazolyl group, 1H
-Indadoryl group, benzimidazolyl group, chromenyl group, chromanyl group, isochromanyl group, quinolinyl group,
Isoquinolinyl group, cinnolinyl group, phthalazinyl group,
A quinazonilyl group, a quinoxalinyl group, a dibenzofuranyl group, a carbazolyl group, a xanthenyl group, an acridinyl group, a phenanthridinyl group, a phenazinyl group, a phenoxazinyl group, a thianthrenyl group and the like can be used.

In R ³¹ , the aromatic heterocyclic group formed by condensation with R ³⁰ and a benzene ring having a hydroxyl group is, for example, a thienyl group, a furyl group, a pyrrolyl group, an oxazolyl group, an isoxazolyl group or a thiazolyl group. Group, isothiazolyl group, imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, pyridyl group, thiazolyl group can be used. Further, 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 and the like.

In R ³³ and R ³⁵ , examples of the divalent chain hydrocarbon include ethylene group, propylene group and butylene group, and examples of the divalent aromatic hydrocarbon include phenylene group. , A naphthylene group, a phenanthrylene group and the like can be used.

As the heterocyclic group for R ³⁴ , for example, a pyridyl group, a pyrazyl group, a thienyl group, an indolyl group and the like can be used.

In R ³⁵ , the atomic group necessary to form a heterocycle with the moiety represented by the general formula (h) is, for example, phenylene group, naphthylene group, phenanthrylene group, ethylene group, propylene group. , Butylene groups and the like can be used.

The aromatic heterocyclic group formed by R ³⁵ and the moiety represented by the general formula (h) is, for example, a benzimidazole group, a benzo [f] benzimidazole group or a dibenzo [e] group. , g] Benzimidazole group, benzopyrimidine group and the like can be used. These groups are
It may have the same substituents as described above.

As the ester of the carboxyl group in R ³⁶ , for example, methyl ester, ethyl ester, propyl ester, butyl ester and the like can be used.

Specific examples of the coupler residues A ₁ and A ₂ represented by the above general formulas (a) to (g) include groups represented by the following formulas (A1) to (A27).

[0065]

[Chemical 12]

[0066]

[Chemical 13]

[0067]

[Chemical 14]

[0068]

[Chemical 15]

Specific examples of the bisazo pigment represented by the above general formula (II) include, for example, the following formulas (B1) to (B11).
The compounds shown in are listed.

[0070]

[Chemical 16]

[0071]

[Chemical 17]

[0072]

[Chemical 18]

Further, the bisazo pigment represented by the general formula (II) has an advantage that it is excellent in repetitive characteristics while maintaining high charge generation efficiency by using the perylene pigment together.

Specific examples of the above-mentioned perylene pigments include compounds represented by the following formulas (C1) to (C7).

[0075]

[Chemical 19]

[0076]

[Chemical 20]

[0077]

[Chemical 21]

(Charge Transport Material) As the charge transport material,
Various electron-withdrawing compounds used in electrophotographic photoreceptors,
An electron donating compound can be used.

Examples of the electron-withdrawing compound include 2,
Diphenoquinone derivatives such as 6-dimethyl-2 ′, 6′-ditert-dibutyldiphenoquinone, malononitrile, thiopyran compounds, tetracyanoethylene, 2,
4,8-trinitrothioxanthone, 3,4,5,7-
Tetranitro-9-fluorenone, dinitrobenzene,
Examples thereof include dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, and dibromomaleic anhydride.

As the electron donating compound, 2,5
-Oxadiazole compounds such as di (4-methylaminophenyl) and 1,3,4-oxadiazole, 9-
Styryl compounds such as (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,
Examples thereof include nitrogen-containing cyclic compounds such as triazole compounds and condensed polycyclic compounds.

These charge transport materials may be 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.

Among these charge-transporting materials, triphenylamine compounds having excellent charge-transporting ability are preferably used.

Specific examples of the above triphenylamine compound include compounds represented by the following formulas (D1) to (D4).

[0084]

[Chemical formula 22]

[0085]

[Chemical formula 23]

(Binder Resin) As the binder resin, various resins can be used. For example, styrene polymer, styrene-
Butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, vinyl chloride-vinyl acetate Copolymer, polyester alkyd resin, polyamide,
Thermoplastic resin such as polyurethane, polycarbonate, polyarylate, polysulfone, diallylphthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, polyester resin, or silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, etc. A crosslinkable thermosetting resin and a photocurable resin such as epoxy acrylate or urethane-acrylate may be used. These binder resins may be used alone or in combination of two or more.

(Conductive Substrate) As the conductive substrate on which the organic photosensitive layer is formed, various conductive materials can be used, such as aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, Metal simple substance such as cadmium, titanium, nickel, palladium, indium, stainless steel, brass, a plastic material in which the above metal is vapor-deposited or laminated, or aluminum iodide,
Examples thereof include glass coated with tin oxide, indium oxide and the like.

The conductive substrate may be in the form of a sheet, a drum or the like, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. Also,
It is preferable that the conductive substrate has sufficient mechanical strength when used.

(Additive) In addition to the pyridine compound, additives such as a sensitizer, a fluorene compound, an antioxidant, a deterioration inhibitor such as an ultraviolet absorber, and a plasticizer are used in combination in the organic photosensitive layer. Can be made.

In order to improve the sensitivity of the charge generating layer, known sensitizers such as terphenyl, halonaphthoquinones and acenaphthylene may be used in combination with the charge generating material.

(Construction of Photoreceptor) The photoreceptor of the present invention can be applied to either a single layer type or a laminated type as a photosensitive layer. However, since the effect of the combination of the charge generating material and the charge transporting material becomes more remarkable especially in the single layer type photosensitive layer in which both materials are contained in the same layer, the present invention provides a single layer type photosensitive layer. More preferably, it is applied to an electrophotographic photoreceptor having a layer.

The single-layer type photoreceptor is a conductive substrate containing a photosensitive layer containing a charge-generating material, a charge-transporting material, the pyridine compound used in the present invention, and a binder resin by means of coating or the like. Can be formed on.

In the laminated type photoreceptor, a charge generating layer containing the charge generating material is formed on a conductive substrate by means such as vapor deposition or coating, and the charge generating layer is formed on the charge generating layer.
A charge transport layer containing the charge transport material and a binder resin can be formed.

On the contrary to the above, the charge transport layer may be formed on the conductive substrate, and then the charge generation layer may be formed.

The pyridine compound used in the photoreceptor of the present invention may be contained in the above charge generation layer and / or charge transport layer.

In the multi-layer type photoreceptor, the charge generating material and the binder resin constituting the charge generating layer may be used in various ratios, but to 100 parts of binder resin (weight part, the same applies hereinafter), Charge generation material 5 to 1000 parts, especially 30 to 500
It is preferably used in a ratio of parts.

The charge transporting material constituting the charge transporting layer and the binder resin can be used in various proportions within a range that does not hinder the transport of charge and a range that does not crystallize, but in the charge generating layer by light irradiation. In order to easily transport the generated charges, the charge transport materials 10 to 5 are added to 100 parts of the binder resin.
It is preferably used in an amount of 00 parts, particularly 25 to 200 parts.

The thickness of the laminated photosensitive layer is preferably 0.01 to 5 μm for the charge generation layer and 0.1 to 3 μm for the specific layer, and 2 to 100 μm for the charge transport layer.
m, particularly preferably about 5 to 50 μm.

In the single-layer type photoreceptor, the binder resin 10
It is preferable that the charge generation material is 0.1 to 50 parts, preferably 0.5 to 30 parts, and the charge transport material is 20 to 200 parts, preferably 30 to 150 parts, relative to 0 parts. The thickness of the single-layer type photosensitive layer is 5 to 100 μm, particularly 10 to 50 μm.
It is preferably formed to have a thickness of about μm.

In the case of a single-layer type photoreceptor, it is between a conductive substrate and a photosensitive layer, and in the case of a laminated type photoreceptor, it is between a conductive substrate and a charge generating layer, and a conductive substrate. A barrier layer may be formed between the charge transport layer and the charge transport layer or between the charge generation layer and the charge transport layer to the extent that the characteristics of the photoreceptor are not impaired, and a protective layer may be formed on the surface of the photoreceptor. .

The pyridine compound used in the photoreceptor of the present invention is 0.05 or less with respect to 100 parts by weight of the binder resin in the layer to be added in any of the single-layer photoreceptor and the laminated photoreceptor.
It is preferable to add 1 part to 10 parts, and more preferably 0.05 part to 3 parts. If the amount added is less than 0.05 part, the effect of addition is not sufficient, and if it exceeds 10 parts, the sensitivity and repeatability of the photosensitive layer deteriorate.

(Production of Photoreceptor) Each of the above layers can be formed by coating, and the charge generating material, charge transporting material, binder resin and the like exemplified above can be mixed with a suitable solvent by a known method such as a roll mill or a ball mill. , An attritor, a paint shaker, an ultrasonic disperser or the like may be mixed and dispersed to prepare a coating solution, which is coated by a known means and dried.

Various organic solvents can be used as the solvent for preparing the coating liquid. For example, alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene. Halogenated hydrocarbons,
Dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, and other ethers, acetone, methyl ethyl ketone, cyclohexanone, and other ketones, ethyl acetate, methyl acetate, and other esters, dimethylformaldehyde, dimethylformamide, dimethyl sulfoxide, etc. are used. obtain. These solvents may be used alone or in combination of two or more.

Further, in order to improve the dispersibility of the charge transport material or the charge generating material and the smoothness of the surface of the photosensitive layer, a surface active agent, a leveling agent, etc. may be used.

[0105]

The present invention will be described in detail below with reference to examples and comparative examples.

(Examples 1 to 12 (single-layer type photoreceptor)) 4 parts by weight of charge generating material, 100 parts by weight of charge transporting material, pyridine compound (addition amount is specifically disclosed in Table 2), bisphenol A polycarbonate (100 parts by weight) and dichloromethane (800 parts by weight) were dispersed for 4 hours in a paint shaker to prepare a single layer type photosensitive layer coating solution. This coating solution was applied on an aluminum sheet with a wire bar to a film thickness of 20 μm, and dried at 100 ° C. for 1 hour to obtain a positive charging type single layer type electrophotographic photoreceptor.

The charge generating materials used are as follows.

[0108]

[Chemical formula 24]

[0109]

[Chemical 25]

[0110]

[Chemical formula 26]

[0111]

[Chemical 27]

The charge transport materials used are as follows.

[0113]

[Chemical 28]

[0114]

[Chemical 29]

(Comparative Examples 1 to 4 (single-layer photoconductor))
A positively chargeable single-layer type electrophotographic photosensitive member was obtained in the same manner as in the above-mentioned examples except that the following compounds were used instead of the pyridine compound as an additive.

The compounds used are specifically as follows.

[0117]

[Chemical 30]

[0118]

[Chemical 31]

Table 2 below shows the types and amounts of the charge generating materials, charge transporting materials, and compounds as additives used in Examples 1 to 12 and Comparative Examples 1 to 4. The notation of the type of the pyridine-based compound of Examples 1 to 12 in Table 2 uses the compound number in Table 1 above.

[0120]

[Table 2]

(Examples 13 to 21 (Layered Photoreceptor)) 15 parts by weight of the charge generating material was dispersed in 285 parts by weight of dichloromethane, and 3 parts by weight of polyvinyl butyral as a binder resin was added to 7 parts by weight. Add the one dissolved in dichloromethane and disperse it with a paint shaker for 4 hours, and add 50 parts of the charge generation material to 100 parts by weight of the binder resin.
0 part by weight of dispersion was obtained.

The obtained dispersion was applied to an aluminum sheet with a wire bar and dried to form a charge generation layer having a film thickness of 0.5 μm.

On this charge generation layer, a solution of the composition for charge transport layer having the composition shown in Table 3 below was applied with a wire bar at a thickness of 2
It was coated at 0 μm and dried at 120 ° C. for 1 hour to form a charge transport layer, to obtain a negative charging type laminated electrophotographic photoreceptor.

[0124]

[Table 3]

The charge generating materials other than those used in Examples 1 to 12 are as follows.

[0126]

[Chemical 32]

[0127]

[Chemical 33]

[0128]

[Chemical 34]

[0129]

[Chemical 35]

(Comparative Examples 5 to 8 (Layered Photosensitive Member))
A negatively-charged laminated electrophotographic photosensitive member was obtained in the same manner as in the above example except that the above compound was used instead of the pyridine compound as an additive.

Table 4 below shows the type and amount of the charge generating material, the charge transporting material, and the compound as an additive used in Examples 13 to 21 and Comparative Examples 5 to 8.

[0132]

[Table 4]

The following tests were carried out on the electrophotographic photoreceptors of the above-mentioned respective Examples and Comparative Examples to evaluate their characteristics.

(Electrical Properties) The flow-in current value was adjusted by an electrostatic copying tester (Gentec Cynthia 30M manufactured by Gentec) to adjust the sheet-shaped electrophotographic photosensitive members prepared in the respective Examples and Comparative Examples. After the surface was charged to about ± 800 V and the initial surface potential (V) was measured, the half-exposure amount was measured using 550 nm light, which is most necessary for a PPC photoreceptor. That is, the intensity of 550 nm light extracted from the xenon lamp using a spectroscope is 0.2 mW / cm.
² 、 Exposure time 1 second, half exposure amount (μJ / c
m ² ) was calculated. Further, the surface potential at the time point when 0.5 seconds passed immediately after the exposure was determined as the post-exposure potential (V).

(Repeatability) The electrophotographic photoconductors obtained in the above Examples and Comparative Examples were attached on aluminum cylinders with adhesive tapes, and then electrostatic copier DC-1670M (Sanda Industrial Co., Ltd.). (Made by the company).

Next, copying was repeated 10,000 times, and the electrophotographic photosensitive member at the initial stage and after repeating 10,000 times was peeled from the aluminum cylinder, and the surface potential (V), half-exposure amount (μJ / cm ² ), The post-exposure potential (V) was measured in the same manner as above. (However, the flow-in current value was set to the same value at the initial stage and after repeating 10,000 times.) The above results are shown in Table 5 (Examples 1 to 12 and Comparative Examples 1 to 4) and Table 6 (Examples 13 to 21). And Comparative Example 5
~ 8).

[0137]

[Table 5]

[0138]

[Table 6]

As is clear from Tables 5 and 6, the electrophotographic photosensitive member of the present invention was excellent in charging property, post-exposure potential, half-exposure amount and repetitive property. On the other hand, the electrophotographic photosensitive member of the comparative example containing no pyridine-based compound was extremely inferior in charging characteristics by repeated use, and the half-exposure amount was deteriorated.

(NO _x resistance) Examples 1 to 5, 7, 1 above
3, 14, 17, 18 and surface potentials (V) and half-exposure amount (μJ / c) of the electrophotographic photoreceptors obtained in Comparative Examples 1 to 8.
m ² ) was determined in the same manner as above, after initial and closed system exposure to 50 ppm NO ₂ for 4 days. (However,
The flow-in current value was the same as the initial value and after the exposure. ) The above results are shown in Table 7 (Examples 1 to 5, 7 and Comparative Examples 1 to 1).
4) and Table 8 (Examples 13, 14, 17, 18 and Comparative Examples 5-8).

[0141]

[Table 7]

[0142]

[Table 8]

As is clear from Tables 7 and 8, the electrophotographic photosensitive member of the present invention was excellent in charging characteristics, half-exposure amount and NO _x resistance. On the other hand, the electrophotographic photoreceptor of Comparative Example containing no pyridine-based compound was
When exposed to O _x , the charging property was extremely deteriorated and the half exposure amount was deteriorated.

[0144]

According to the present invention, by the inclusion of general formula (I) pyridine compound represented by along with the charge generating material or charge-transporting material, an electrophotographic having excellent repetition characteristics and resistance to NO _x resistance It is possible to provide a photoreceptor for use.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keisuke Sumita 1-22-28 Tamatsukuri, Chuo-ku, Osaka Mita Engineering Co., Ltd.

Claims (2)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive layer and a photosensitive layer containing a charge generating material, a charge transporting material, and a pyridine compound, wherein the pyridine compound is
It is represented by the following general formula (I): (Here, R < ₁ > shows a hydrogen atom, a halogen atom, or a C1-C10 alkyl group, an alkoxy group, an aryl group, or an aralkyl group which may have 1 or 2 or more substituents.). 2. The electrophotographic photosensitive member according to claim 1, wherein the charge generation material is a bisazo pigment represented by the following general formula (II): (Here, A ₁ and A ₂ are each an independent coupler residue, R ₂ is a hydrogen atom, or an alkyl group, an aryl group, or a heterocyclic group which may have one or more substituents, n ₁ represents 0 or 1.).