JP2996487B2 - m-phenylenediamine compound and electrophotographic photoreceptor using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an m-phenylenediamine compound suitable as a charge transporting material in an electrophotographic photoreceptor and an electrophotographic photoreceptor using the same.

[Prior Art] In recent years, as an electrophotographic photoreceptor in an image forming apparatus such as a copying machine, an organic photoreceptor which has excellent workability, is advantageous in terms of manufacturing cost, and has a high degree of freedom in functional design has been used. I have.

When a copy image is formed using an electrophotographic photosensitive member, the Carlson process is widely used. The Carlson process includes a charging step of uniformly charging the photoreceptor by corona discharge, an exposure step of exposing an original image on the charged photoreceptor, and forming an electrostatic latent image corresponding to the original image,
Developing the electrostatic latent image with a developer containing toner to form a toner image; transferring the toner image to a base material such as paper; and fixing the toner image transferred to the base material It includes a fixing step and a cleaning step for removing the toner remaining on the photoconductor after the transfer step. In order to form a high-quality image in the Carlson process, it is required that the electrophotographic photosensitive member has excellent charging characteristics and photosensitive characteristics, and that the residual potential after exposure is low.

One of the means for achieving these properties is to select an appropriate charge transport material. Many compounds such as polyvinyl carbazole, oxadiazole-based compounds, pyrazoline-based compounds, and hydrazone-based compounds have been proposed as the charge transporting material.

[Problems to be Solved by the Invention] However, the charge transport material has a relatively small drift mobility indicating charge transport ability. In addition, since the electric field strength dependence of the drift mobility is large, there is a problem that the movement of the electric charge in a low electric field is small and the residual potential is hard to be removed. Furthermore, there is a problem that it is easily deteriorated by irradiation of ultraviolet rays.

In order to solve such problems, the electric field dependence of the drift mobility is small, and N, N, N ', N'-tetraphenyl-m-phenylenediamine compound having good compatibility with the resin is used.
1,3-phenylenediamine has been proposed (Japanese Patent Application No. Sho 62)
-301703). This m-phenylenediamine compound has good light resistance to ultraviolet light and the like, and shows stable characteristics even when used in an actual copying machine. However, there is a problem that, when the copier is out of order and the light exposure is performed for a long time or under a high temperature, irreparable damage is caused.

An object of the present invention is to solve the above-mentioned problems and to provide an m-phenylenediamine compound having more light resistance and excellent light stability, and an electrophotographic photoreceptor using the same.

[Means and Actions for Solving the Problems] Generally, the cause of the deterioration of the photoconductor characteristics due to light deterioration is that impurities serving as traps for the charge transport material are generated in the photoconductor. In the case of the m-phenylenediamine compound, a ring-closing reaction that occurs between the central benzene ring and the second position of another phenyl group is considered as such a photodegradation reaction. This reaction is considered to occur easily because the electron density of the phenylenediamine-based compound molecule is biased toward the central benzene ring. Therefore, as a result of various experiments, in order to reinforce the 2-position of the phenyl group bonded to each nitrogen atom added to the central benzene ring, the 2- and 3-positions are condensed with another phenyl group to form a naphthyl group. , The reaction point 2
It has been found that it is possible to suppress the reactivity of the phenylenediamine-based compound by protecting the position and improve the stability to light.

Thus, the first m-phenylenediamine compound of the present invention has the following general formula [I] (In the formula, R ¹ , R ² , R ³ , R ⁴ , and R ⁵ are the same or different and each represents an alkyl group, an alkoxyl group, or a halogen atom, each of which may be unsubstituted or substituted as many as possible. In addition, the above group: And may form a condensed ring at the 2,3-position with a phenyl group which may have a substituent. ) Is an m-phenylenediamine compound represented by the formula:

The m-phenylenediamine-based compound represented by the general formula [I] is obtained by adding one naphthyl group and one phenyl group to each nitrogen atom added to the central benzene ring. It includes the case where two naphthyl groups are added to a nitrogen atom. In any case, since the 2-position which is the reaction point is protected, it is hardly attacked by an oxidizing substance or the like, the ring closure reaction is suppressed, and the stability to light is improved.

Further, the photoreceptor containing each of the above m-phenylenediamine-based compounds is less susceptible to long-term light exposure or light exposure at high temperatures than conventional photoreceptors,
Excellent light stability.

[Preferred Embodiment of the Invention] In the m-phenylenediamine compound of the present invention represented by the general formula [I], the alkyl group among R ¹ , R ² , R ³ , R ⁴ and R ⁵ is a methyl group , Ethyl group, propyl group,
Examples thereof include lower alkyl groups having 1 to 6 carbon atoms such as isopropyl group, butyl group, isobutyl group, tertbutyl group, pentyl group, and hexyl group.

Examples of the alkoxyl group include a methoxy group, an ethoxy group,
Propoxy group, isopropoxy group, pentyloxy group,
An alkyl moiety such as a hexyloxy group having 1 to 6 carbon atoms;
Are exemplified.

The above R ¹ , R ² , R ³ , R ⁴ , and R ⁵ may be substituted at any position in any number, and may not be substituted. Further, these substituents R ¹ , R ² , R ³ , R ⁴ and R ⁵ may be the same or different from each other.

Specific examples of the m-phenylenediamine-based compound represented by the general formula [I] include compounds having the following substituents.

The compound of the present invention can be synthesized by various methods, and the compound represented by the above general formula [I] includes, for example,
It can be synthesized by the following reaction formula [A].

Reaction formula [A]: [Wherein, R ⁿ and R ^s are the same or different and each represents an alkyl group, an alkoxyl group, or a halogen atom, and each may be unsubstituted or may be substituted as many as possible. That is, in the above reaction step [A], the resorcinol derivative represented by the formula (1) and the naphthylamine derivative represented by the above formula (2) are reacted with iodine by refluxing under a nitrogen stream, A phenylenediamine compound represented by the above formula (3) is obtained. Next, the compound of the above formula (3) and the iodobenzene derivative represented by the above formula (4) are refluxed together with potassium carbonate and copper powder in a solvent (for example, nitrobenzene),
In the general formula [I], a compound of the present invention in which R ¹ and R ³ and R ² and R ⁴ each have the same substituent can be synthesized.

In the above compound, the substituent R ⁵ such as an alkyl group can be previously introduced to, for example, resorcinol, as described above, and R ² and R ⁴ are previously introduced to 1-naphthylamine, and further, The substituents R ¹ and R ³ can be previously introduced into iodobenzene.

The compound of the present invention can also be synthesized by the following reaction formula [B] or [C].

Reaction formula [B]: [Wherein R ⁿ , R ^s and R ⁵ are the same as described above] Reaction formula [C]: Wherein R ⁿ and R ⁵ are the same as above. That is, in the reaction formula [B], the resorcinol derivative represented by the formula (5) and the naphthylamine derivative represented by the formula (6) are refluxed together with iodine under a nitrogen stream, and thereby represented by the formula (7). To obtain a phenylenediamine compound. Next, the compound of the present invention is synthesized by reacting the compound of the formula (7) with the iodonaphthalene derivative represented by the formula (8) together with potassium carbonate and copper powder by refluxing in a solvent (for example, nitrobenzene). Can be.

Further, the compound of the present invention can also be synthesized by the reaction represented by the reaction formula [C]. That is, it can be synthesized by adding the m-phenylenediamine derivative (9) and the iodonaphthalene derivative (10) together with potassium carbonate and copper powder to a solvent (for example, nitrobenzene) and causing a reflux reaction. However, R ¹ to R ¹ in the general formula [I]
R ⁴ are all the same substituent.

In order to synthesize a compound of the present invention other than the compound obtained by the above reaction formula [A], [B] or [C], for example, a compound in which R ^{1 to} R ⁴ are all different substituents, the above reaction formula A method in which the molar ratio of the starting materials in [A], [B] or [C] is appropriately adjusted, and each phenyl group having substituents R ^{1 to} R ⁴ is introduced stepwise. Further, after introducing a phenyl group having no substituent, the substituents R ^{1 to} R ^{4 and} further R ⁵
May be sequentially introduced.

The compound of the present invention represented by the general formula [I] can be used in combination with another known charge transport material. As the charge mailing material in this case, various known electron-withdrawing compounds and electron-donating compounds can be used.

Examples of the electron withdrawing compound include, for example, diphenoquinone derivatives such as 2,6-dimethyl-2 ', 6'-ditert-dibutyldiphenoquinone, malononitrile, thiopyran-based compounds, tetracyanoethylene, and 2,4,8- Examples include trinitrothioxanthone, 3,4,5,7-tetranitro-9-fluorenone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride and the like. .

Examples of the electron donating compound include oxadiazole compounds such as 2,5-di (4-methylaminophenyl) and 1,3,4-oxadiazole, and 9- (4-diethylaminostyryl) anthracene. Carbazole compounds such as styryl compounds and 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,
Examples thereof include nitrogen-containing cyclic compounds such as pyrazole compounds and triazole compounds, and condensed polycyclic compounds.

These charge transport materials are used alone or in combination of two or more. When a charge transporting material having a film forming property such as polyvinyl carbazole is used, a binder resin is not necessarily required.

Each compound represented by the general formula [I] can be applied to any of so-called single-layer type and laminated type electrophotographic photoreceptors.

To form a single-layer type electrophotographic photoreceptor, a photosensitive layer containing a compound represented by the general formula [I] as a charge transporting material, a charge generating material, a binder resin and the like is formed on a conductive substrate. do it.

Further, in order to form a laminate type electrophotographic photoreceptor, a charge generation layer containing a charge generation material is formed on a conductive substrate by a method such as evaporation or coating, and on this charge generation layer,
What is necessary is just to form a charge transport layer containing the compound represented by the general formula [I] and the binder resin. Also, contrary to the above, a charge transport layer similar to the above is formed on a conductive substrate,
Next, a charge generation layer containing a charge generation material may be formed by means such as vapor deposition or 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.

Examples of the charge generation material include selenium, selenium-tellurium, amorphous silicon, pyrylium salts, azo pigments, disazo pigments, anthanthrone pigments, phthalocyanine pigments, indigo pigments, triphenylmethane pigments, and sulene pigments. Pigments, toluidine-based pigments, pyrazoline-based pigments, perylene-based pigments, quinacridone-based pigments, pyrrole-based pigments and the like are exemplified, and one kind or a mixture of two or more kinds is used to have an absorption wavelength range in a desired region.

Various resins can be used as the binder resin in the photosensitive layer, the charge generation layer, and the charge transport layer. For example, a styrene-based polymer, a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, a styrene-maleic acid copolymer, an acrylic polymer, a styrene-acrylic copolymer, a polyethylene, and an ethylene-vinyl acetate copolymer , Chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin Thermoplastic resins such as silicone resins, epoxy resins, phenolic resins, urea resins, melamine resins, other cross-linkable thermosetting resins, and photo-curable resins such as epoxy acrylate and urethane-acrylate. Polymers are exemplified. These binder resins are used alone or in combination of two or more.

Further, when forming the charge generation layer and the charge transport layer by a coating method, a solvent is used. As this solvent,
Various organic solvents can be used, such as alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, and aromatic hydrocarbons such as benzene, toluene and xylene. Halogenated hydrocarbons such as hydrogen, dichloromethane, dichloroethane, carbon tetrachloride, and chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, and acetic acid Various solvents such as esters such as methyl, dimethylformaldehyde, dimethylformamide and dimethylsulfoxide are exemplified.
Species or a mixture of two or more can be used.

In order to improve the sensitivity of the charge generation layer, a known sensitizer such as terphenyl, halonaphthoquinones, and acenaphthylene may be used together with the charge generation material. Further, a surfactant, a leveling agent, and the like may be used to improve the dispersibility, dyeing property, and the like of the charge transporting material and the charge generating material.

As the conductive substrate, various materials having conductivity can be used, for example, aluminum, copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium,
Examples include metal units such as cadmium, titanium, nickel, palladium, indium, stainless steel, and brass; plastic materials on which the above metals are deposited or laminated; aluminum iodide, tin oxide, and glass coated with indium oxide. You. The conductive substrate may be in a sheet shape or a drum shape, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. The substrate preferably has sufficient mechanical strength when used.

The compound of the present invention and the binder resin as the charge transport material can be used in various ratios within a range not inhibiting the charge transport and a range not causing crystallization, but based on 100 parts by weight of the binder resin. It is preferable to use 125 to 200 parts by weight of the compound represented by the above general formula [I]. Further, the charge transport layer containing the compound represented by the general formula [I] is preferably formed with a layer thickness of about 2 to 100 μm, particularly about 5 to 30 μm.

When the charge generating material is used together with a binder resin, the charge generating material and the binder resin can be used in various ratios. It is desirable to use in the ratio of.

The thickness of the charge generation layer containing the charge generation material can be arbitrarily selected, but is preferably 0.01 to 20 μm, particularly
It is desirable to form it to about 0.1 to 10 μm.

The thickness of the single-layer type photosensitive layer in which the compound represented by the general formula [I] and the charge generating material are present in a single layer can be arbitrarily selected.
The layer thickness is preferably about 30 μm.

In the case of a single-layer type electrophotographic photoreceptor, between the substrate and the photosensitive layer, and in the case of the laminated type electrophotographic two photoreceptor, between the substrate and the charge generating layer or between the substrate and the charge generating layer. A barrier layer may be formed between the transport layer and between the charge generation layer and the charge transport layer as long as the properties of the photoreceptor are not impaired, and a protective layer is formed on the surface of the photoreceptor. You may.

When the charge generation layer and the charge transport layer are formed by a coating method, a charge generation material or the like and a binder resin or the like are known in the art, for example, a roll mill, a ball mill, an attritor, a paint shaker, an ultrasonic disperser, or the like. May be prepared by dispersing and mixing, and then applied and dried by known means. Note that, as described above, the charge generation layer may be formed by vapor deposition of the charge generation material.

 Hereinafter, the present invention will be described in detail with reference to examples.

Examples (1) Synthesis Example of Charge Transport Material First Synthesis Example (N, N'-bis (1-naphthyl) -N, N'-bis (3-tolyl) -1,3-phenylenediamine Synthesis) 9.7 g of resorcinol and 25.2 g of 1-naphthylamine were reacted under reflux in a nitrogen stream for 3 days in the presence of 0.5 g of iodine to give N, N'-bis (1-naphthyl) -1,3-phenylenediamine I got Next, 9.0 g of this N, N'-bis (1-naphthyl) -1,3-phenylenediamine, 10.9 g of m-iodotoluene, 5.0 g of potassium carbonate and 1.5 g of copper powder were added to 50 ml of nitrobenzene and refluxed for 24 hours. To give the title compound N, N'-bis (1-naphthyl) -N, N'-bis (3-tolyl) -1,3-phenylenediamine (Compound 1 of the present invention). The melting point of this compound was 172-173 ° C.

Second Synthesis Example (Synthesis of N, N'-bis (1-naphthyl) -N, N'-bis (phenyl) -1,3-phenylenediamine) 9.7 g of resorcinol and 25.2 g of 1-naphthylamine were mixed with 0.5 of iodine. In the presence of g, the reaction was carried out by refluxing in a nitrogen stream for 3 days to obtain N, N'-bis (1-naphthyl) -1,3-phenylenediamine. Next, 9.0 g of this N, N'-bis (1-naphthyl) -1,3-phenylenediamine, 10.2 g of iodobenzene, 5.0 g of potassium carbonate and 1.5 g of copper powder were added to 50 ml of nitrobenzene, and the mixture was refluxed for 24 hours and reacted. Then, the title compound N, N'-bis (1-naphthyl) -N, N'-bis (phenyl) -1,3-phenylenediamine (Compound 2 of the present invention) was obtained. The melting point of this compound was 176-177 ° C.

Third Synthesis Example (N, N'-bis (8-methoxy-1-naphthyl) -N, N '
-Bis (3-methoxyphenyl) -5-methyl-1,3-
Synthesis of phenylenediamine) 10.9 g of 5-methylresorcinol and 8-methoxy-1
-Naphthylamine was reacted with 30.4 g of naphthylamine in the presence of 0.5 g of iodine by refluxing in a nitrogen stream for 3 days to give N, N'-bis (8-
(Methoxy-1-naphthyl) -5-methyl-1,3-phenylenediamine was obtained. Next, the N, N'-bis (8-
(Methoxy-1-naphthyl) -5-methyl-1,3-phenylenediamine 10.9 g, m-methoxyiodobenzene 11.7 g
g, potassium carbonate 5.0 g and copper powder 1.5 g were added to nitrobenzene 50 ml, and the mixture was refluxed for 24 hours to react.
N, N'-bis (8-methoxy-1-naphthyl) -N, N'-
Bis (3-methoxyphenyl) -5-methyl-1,3-phenylenediamine (Compound 3 of the present invention) was obtained. The melting point of this compound was 186-187 ° C.

Fourth Synthesis Example (N, N'-bis (8-chloro-1-naphthyl) -N, N '
(Synthesis of 3-tolyl) -5-chloro-1,3-phenylenediamine 12.7 g of 5-chlororesorcinol and 8-chloro-1-
N, N'-bis (8-chloro-1-naphthyl) -5-chloro-1,3-phenylenediamine was reacted with 31.2 g of naphthylamine by refluxing for 3 days in a nitrogen stream in the presence of 0.5 g of iodine. I got Next, 23.2 g of this N, N'-bis (8-chloro-1-naphthyl) -5-chloro-1,3-phenylenediamine, 11.9 g of m-chloroiodobenzene, 5.0 g of potassium carbonate and 1.5 g of copper powder were added. The mixture was added to 50 ml of nitrobenzene and reacted under reflux for 24 hours to give the title compound N, N'-bis (8-chloro-1-naphthyl) -N, N'-bis (3-
(Chlorophenyl) -5-chloro-1,3-phenylenediamine (Compound 4 of the present invention) was obtained. The melting point of this compound is
134-135 ° C.

Fifth Synthesis Example (Synthesis of N, N, N ', N'-tetrakis (6-methyl-1-naphthyl) -5-methyl-1,3-phenylenediamine) 5-methylresorcinol (orcin) 10.9 g And 6-
The mixture was reacted with 27.6 g of methyl-1-naphthylamine by refluxing for 3 days in a stream of nitrogen in the presence of 0.5 g of iodine to give N, N'-.
Bis (6-methyl-1-naphthyl) -5-methyl-1,3
-Phenylenediamine was obtained. This N, N'-bis (6-
Methyl-1-naphthyl) -5-methyl-1,3-phenylenediamine 10.1 g, 6-methyl-1-iodonaphthalene 1
3.4 g, potassium carbonate 5.0 g and copper powder 1.5 g were added to nitrobenzene 50 ml, and the mixture was refluxed for 24 hours and reacted to give the title compound (N, N, N ', N'-tetrakis (6-methyl-1-naphthyl)) This gave -5-methyl-1,3-phenylenediamine (Compound 5 of the present invention), which had a melting point of 173 to 174 ° C.

Sixth Synthesis Example (Synthesis of N, N, N ', N'-tetrakis (6-methoxy-1-naphthyl) -5-methyl-1,3-phenylenediamine 3.1 g of 5-methylphenylenediamine, 6- Methoxy-
1-Iodonaphthalene 28.4 g, potassium carbonate 6.9 g, copper powder
The mixture was added to 100 ml of nitrobenzene together with 1.5, and the mixture was refluxed for 24 hours and reacted to give the title compound N, N, N ', N'-tetrakis (6-methoxy-1-naphthyl) -5-methyl-1,3-phenylenediamine (Compound 6 of the present invention) was obtained. The melting point of this compound was 179-180 ° C.

Seventh Synthesis Example (Synthesis of N, N, N ', N'-tetrakis (6-chloro-1-naphthyl) -4-methyl-1,3-phenylenediamine) 3.1 g of 4-methylphenylenediamine, 7- Chloro-1
-28.9 g of iodonaphthalene, 6.9 g of potassium carbonate, and 1.5 of copper powder
g and 100 g of nitrobenzene, and the mixture was refluxed for 24 hours and reacted to give the title compound N, N, N ', N'-tetrakis (7-chloro-1-naphthyl) -4-methyl-1,
3-phenylenediamine (Compound 7 of the present invention) was obtained. The melting point of this compound was 122-123 ° C.

(2) Preparation of electrophotographic photoreceptor Preparation of single-layer type electrophotographic photoreceptor N, N'-di (3,5dimethylphenyl) perylene-3,4,9,10-tetracarboxydiimide 8 as a charge generating material
Parts by weight, 100 parts by weight of the compound of the present invention synthesized in the above Synthesis Examples 1 to 4 as a charge transporting material, and poly (4,4'-cyclohexylidenediphenyl) carbonate (polycarbonate Z200, manufactured by Mitsubishi Gas Chemical Company) as a binder resin. 100 parts by weight and a predetermined amount of tetrahydrofuran are combined and dispersed by an ultrasonic disperser to prepare a single-layer type photosensitive layer coating solution. This coating solution was applied to an aluminum tube having an outer diameter of 78 mm and a length of 340 mm, and then dried by heating at 100 ° C. for 30 minutes in a dark place to obtain a drum-type electrophotograph having a single-layer photosensitive layer having a thickness of 24 μm. A photoreceptor was made.

Preparation of laminated electrophotographic photoreceptor 100 parts by weight of polyvinyl butyral (trade name: Slek BL1 manufactured by Sekisui Chemical Co., Ltd.) as a binder resin, 100 parts by weight of oxotitanyl phthalocyanine as a charge generating material, and a predetermined amount of tetrahydrofuran are all milled. Charge, 24
Stir and mix for an hour to prepare a coating solution for the charge generation layer, apply this prepared solution to an aluminum drum by dipping,
The film thickness is 0.5
A μm charge generation layer was formed.

Next, 100 parts by weight of a polycarbonate resin (Iupilon, manufactured by Mitsubishi Gas Chemical Company, Ltd.) as a binder resin, 100 parts by weight of each compound synthesized in the above Synthesis Examples 1 to 8 as a charge transport layer, and a predetermined amount of toluene Was stirred and mixed with a homomixer to prepare a coating solution for a charge transport layer. This coating solution was applied to the surface of the charge generation layer by a dipping method,
The resultant was dried with hot air for 30 minutes to form a charge transport layer having a thickness of about 20 μm, thereby producing a laminated electrophotographic photosensitive member.

Comparative Example (N, N, N ', N'-tetrakis (3
Single-layer and laminated electrophotographic photoreceptors were prepared in the same manner as in the above Preparation Example except that 100 parts by weight of (tolyl) -1,3-phenylenediamine were used.

(3) Evaluation of electrophotographic photoreceptor Single-layer electrophotographic photoreceptor (measurement of initial surface potential _VSP ) Each of the above single-layer electrophotographic photoreceptors was subjected to an electrostatic copying tester (Gentec Cynthia 30M, manufactured by Gentec) ), The surface is charged positively, and the surface potential V of each photoreceptor is charged.
_SP (V) was measured.

(Measurement of half-exposure amount and residual potential) Each charged electrophotographic photoreceptor was charged to a halogen lamp (exposure intensity 0.92
mW / cm ²⁾ was exposed using a seek time until the surface potential V _SP is 1/2, were calculated half-life exposure ^{_{E 1/2 (μJ / cm 2)}} .

The surface potential after 0.15 seconds has elapsed from the start of the exposure is defined as a residual potential V _rp (V).

Multilayer electrophotographic photoreceptor Monochromatic light (λ = 780 nm, exposure intensity = 10 μW / cm ² , exposure time = 1) obtained by passing Xe lamp light through a spectroscope as an exposure light source
) To expose each layered electrophotographic photoreceptor using
The surface potential after a lapse of 0.5 seconds was measured as the residual potential _Vrp . Otherwise, the same measurement as in the case of the single-layer type electrophotographic photosensitive member was performed.

Tables 1 and 2 show the measurement results of the charging characteristics and the photosensitive characteristics of the electrophotographic photosensitive members obtained in the above Examples and Comparative Examples.

In Tables 1 and 2, “before exposure” indicates initial characteristics before light irradiation, and “after exposure” indicates characteristics after irradiating white light containing 400 lux ultraviolet light for 40 minutes using a white fluorescent lamp. Show.

As shown in Tables 1 and 2 above, all of the photoreceptors using the compound for a charge transport material of the present invention had an initial surface potential V
It can be seen that _SP , half-exposure amount E _1/2 , and residual potential V _rp have smaller fluctuations in the values before and after exposure than in the comparative example and are excellent in light stability.

[Effects of the Invention] As described above, in the compound for a charge transporting material of the present invention, one or two naphthyl groups are added to each nitrogen atom added to the central benzene ring, the reaction site is protected, and the oxidizing substance is protected. An electrophotographic photoreceptor that is excellent in photostability because it is less susceptible to attack from the like and suppresses the ring closure reaction, and that is excellent in photostability can be obtained by using the charge transport material.

Claims (2)

(57) [Claims] 1. The following general formula [I]: (In the formula, R ¹ , R ² , R ³ , R ⁴ , and R ⁵ are the same or different and each represents an alkyl group, an alkoxyl group, or a halogen atom, each of which may be unsubstituted or substituted as many as possible. In addition, the above group: And may form a condensed ring at the 2,3-position with a phenyl group which may have a substituent. M) A phenylenediamine compound represented by the formula: 2. An electrophotographic photoreceptor comprising a photosensitive layer containing the m-phenylenediamine compound according to claim 1 provided on a conductive substrate.