JPH0759673B2 - M-phenylenediamine compound and electrophotographic photoreceptor using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an m-phenylenediamine compound suitable as a charge transport 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 having excellent processability and advantageous in terms of manufacturing cost and having a large degree of freedom in functional design has been used. There is.

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

One of the means for achieving these properties is the selection of an appropriate charge transport material. Many compounds such as polyvinyl carzol, oxadiazole compounds, pyrazoline compounds, and hydrazone compounds have been proposed as the charge transport material.

[Problems to be Solved by the Invention] However, the charge transport material described above has a relatively low drift mobility indicating a charge transport capability. Further, since the drift mobility has a large dependency on the electric field strength, there is a problem that the movement of charges in a low electric field is small and the residual potential is hard to pass through. Further, there is a problem that it is easily deteriorated by irradiation with ultraviolet rays.

In view of these problems, N, N, N ′, N′-tetraphenyl-1,3 as an m-phenylenediamine compound having a small electric field dependence of drift mobility and good compatibility with a resin.
-Phenylenediamine has been proposed (Japanese Patent Application No. 62-30).
No. 1703). This m-phenylenediamine compound has good light resistance to ultraviolet light and the like, and exhibits stable characteristics even when used in an actual copying machine. However, there is a problem in that when the copying machine is broken down or the light is exposed to light for a long time or at a high temperature, it is irreparably damaged.

The present invention solves the above problems, and an object of the present invention is to provide an m-phenylenediamine compound having more light resistance and excellent photostability, and an electrophotographic photoreceptor using the same.

[Means and Actions for Solving the Problems] Generally, the cause of deterioration of the characteristics of the photoconductor due to photodegradation is that impurities serving as traps for the charge transport material are generated in the photoconductor. In the case of an m-phenylenediamine compound, such a photodegradation reaction is considered to be a ring-closing reaction that occurs between the central benzene ring and another phenyl group. It is considered that this reaction is likely to occur because the electron density of the molecule of the phenylenediamine compound is biased to the central benzene ring. In particular, the 5th position of the central benzene ring has a molecular structure that is easily attacked by an oxidizing substance such as oxygen during photoexcitation due to its steric configuration, and it is considered that a ring-closing reaction occurs because an electron is withdrawn from this part. Therefore, it is thought that it is possible to suppress the reactivity and improve the stability by substituting and protecting this part with a substituent.As a result of various experiments, this position was replaced with an electron-withdrawing substituent. It was found that when substituted, photostability can be improved more effectively than when substituted with other substituents.

The m-phenylenediamine compound of the present invention has the following general formula [I]: (In the formula, R ¹ , R ² , R ³ and R ⁴ are the same or different and are an alkyl group, an alkoxyl group, a halogen atom, an amino group or N
A substituted amino group, l, m, o and p are the same or different and each represents an integer of 0 to ⁵ and R ⁵ represents an electron-withdrawing group). .

Since the m-phenylenediamine compound is protected by the substituent at the 5-position of the central benzene ring, it is less likely to be attacked by an oxidizing substance and the like, and the photodegradation reaction is suppressed, and the stability to light is improved. . Moreover, since the position 5 of the central benzene ring is substituted with an electron-withdrawing group, the electron distribution biased to the central benzene ring is made uniform, so that it is more stable to light than when substituted with other substituents. The property is improved. This can be inferred from the change in the electron density distribution in the ground state obtained by the molecular orbital method calculation.

Further, the photoconductor containing the m-phenylenediamine-based compound is less likely to suffer zammage than the conventional photoconductor when exposed to light for a long time or under high temperature, and is excellent in light stability. There is.

[Preferred Embodiment of the Invention] In the m-phenylenediamine compound of the present invention represented by the general formula [I], the alkyl group of R ¹ , R ² , R ³ and R ⁴ is a methyl group or an ethyl group. And lower alkyl groups having 1 to 6 carbon atoms such as propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group and hexyl.

Examples of the alkoxyl group include lower alkoxy groups having 1 to 6 carbon atoms in the alkyl moiety such as a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a pentyloxy group and a hexyloxy group.

The R ¹ , R ² , R ³ and R ⁴ may be the same or different from each other.

The electron withdrawing group represented by R ⁵ includes a halogen atom, a nitro group, a sulfo group, a cyano group, an aldehyde group,
Group: —COR ⁶ (in the formula, R ⁶ is a hydrogen atom, an alkyl group or an amino group), a carboxyl group, and an esterified carboxyl group.

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

The compound represented by the above general formula [I] of the present invention can be synthesized by various methods. For example, the compound can be synthesized by a series of reaction formula [A] or reaction formula [B] shown below. You can

[Wherein R ⁿ and R ^s are the same or different and are an alkyl group, an alkoxyl group, a halogen atom, an amino group or N
-Indicates a substituted amino group. That is, in the above reaction formula [A], the above formula (1)
The resorcinol derivative represented by and the aniline derivative represented by the above formula (2) are reacted with iodine under reflux in a nitrogen stream to obtain a phenylenediamine compound represented by the above formula (3). Then, the compound of the above formula (3) and the iodobenzene derivative represented by the above formula (4) are added to a solvent together with potassium carbonate and copper powder, and the mixture is refluxed to give R ¹ and R ^{3 in the} above formula [I]. , R ² and R ⁴
To obtain the compounds of the present invention. In addition, as described above, the substituent (electron-withdrawing group) R ⁵ in the compound represented by the general formula [I] can be introduced into resorcinol in advance, and R ² and R ⁴ can be introduced. Can be previously introduced into aniline, and the substituents R ¹ and R ³ can be previously introduced into iodobenzene.

Further, as shown in the above reaction formula [B], the phenylenediamine derivative of the formula (5) and the iodobenzene derivative of the formula (6) are reacted with potassium carbonate and copper powder by refluxing in a solvent to react with the general formula [ In I], compounds of the present invention in which R _{1 to} R ⁴ are all the same substituent can be synthesized.

Further, in order to synthesize the compound of the present invention other than the compound obtained by the above reaction formula [A] or [B], for example, a compound in which R ^{1 to} R ⁴ are all different substituents, the above reaction formula [A] or There is a method in which the molar ratio of the starting materials in [B] is appropriately adjusted and each phenyl group having the 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 R ⁵ may be introduced successively.

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

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

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. Styryl compounds, carbazole compounds such as polyvinylcarbazole, 1-phenyl-
Pyrazoline compounds such as 3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds,
Examples thereof include nitrogen-containing cyclic compounds such as thiadiazole compounds, imidazole compounds, pyrazole compounds, and triazole compounds, and condensed polycyclic compounds.

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.

The compound represented by the general formula [I] can be applied to both so-called single-layer type and multi-layer type electrophotographic photoreceptors.

In order to obtain a single-layer type electrophotographic photoreceptor, a photosensitive layer containing a compound represented by the above general formula [I] which is a charge transport material, a charge generating material, a binder resin and the like is provided on a conductive substrate. It may be formed.

Further, in order to obtain a laminated type electrophotographic photoreceptor, a charge generation layer containing a charge generation material is formed on a conductive substrate by means such as vapor deposition or coating, and the above-mentioned charge generation layer is formed on the charge generation layer. The charge transport layer containing the compound represented by the general formula [I] and the binder resin may be formed. On the contrary to the above, a charge transport layer similar to the above is formed on the conductive substrate,
Then, a charge generating layer containing a charge generating material may be formed by means such as vapor deposition or coating. Further, the charge generation layer may be formed by dispersing a charge generation material and a charge transport material in a binder resin and coating the resin.

Examples of the charge generation material include selenium and selenium-
Tellurium, amorphous silicon, pyrylium salts, azo pigments, disazo pigments, ansanthuron pigments, phthalocyanine pigments, indigo pigments, triphenylmethane pigments, slene pigments, toluidine pigments, pyrazoline pigments, perylene pigments. Examples thereof include quinacridone pigments and pyrrole pigments, and one kind or a mixture of two or more kinds is used so as to have an absorption wavelength range in a desired range.

Further, various binder resins may be used as the binder resin in the photosensitive layer, the charge generation layer and the charge transport layer. For example, styrene-based polymer, styrene-butadiene copolymer, 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 copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin And other thermoplastic resins, silicone resins, epoxy resins, phenol resins, urea resins, melamine resins, other crosslinkable thermosetting resins, and photocurable resins such as epoxy acrylate and urethane-acrylate. Polymers are exemplified. 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. As this solvent, various organic solvents can be used, and alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, benzene, toluene and xylene. Etc.Aromatic hydrocarbons such as, dichloromethane, dichloroethane, carbon tetrachloride, halogenated hydrocarbons such as 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, etc. , Various solvents such as ethyl acetate, esters such as methyl acetate, dimethylformaldehyde, dimethylformamide, dimethylsulfoxide, etc. are exemplified.
One kind or a mixture of two or more kinds can be used.

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

As the conductive substrate, various materials having conductivity can be used, for example, aluminum, copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium,
Examples include cadmium, titanium, nickel, palladium, indium, stainless copper, brass, and other simple metals, plastic materials in which the above metals are vapor-deposited or laminated, aluminum iodide, tin oxide, glass coated with indium oxide, or the like. It The conductive base material may be in the form of a sheet or a drum, and the base material itself may be conductive, or the surface of the base material may be conductive. As the base material, a base material having sufficient mechanical strength when used is preferable.

The compound and the binder resin of the present invention as the charge transport material can be used in various ratios within the range that does not inhibit the charge transport and the range that does not crystallize, but with respect to 100 parts by weight of the binder resin. It is preferable to use 125 parts by weight to 200 parts by weight of the compound represented by the general formula [I].

The charge transport layer containing the compound represented by the general formula [I] is preferably formed to have a layer thickness of 2 to 100 μm, particularly 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, but the binder resin is 1 to 150 parts by weight with respect to 10 parts by weight of the charge generating material. It is desirable to use it in the ratio of.

The thickness of the charge generation layer containing the above charge generation material can be arbitrarily selected, but 0.01 to 20 μm,
In particular, it is desirable to form it to a thickness of about 0.1 to 10 μm.

In addition, the film thickness of the single-layer type photosensitive layer in which the compound represented by the general formula [I] and the charge generation material are present in a single layer can be arbitrarily selected, but is 2 to 100 μm, and particularly 5 ~ 3
The layer thickness is preferably about 0 μm.

Further, in the case of a single-layer type electrophotographic photoreceptor, between the base material and the photosensitive layer, and in the case of a laminated type electrophotographic photoreceptor, between the base material and the charge generation layer. A barrier layer may be formed between the base material and the charge transport layer and between the charge generation layer and the charge transport layer to the extent that the characteristics of the photoreceptor are not impaired. A layer may be formed.

When the charge generation layer and the charge transport layer are formed by a coating method, the charge generation material and the binder resin are known methods, for example, roll mill, ball mill, attritor, paint shaker or ultrasonic disperser. Prepared by dispersing and mixing using a known means.
Just dry. Note that, as described above, the charge generation layer may be formed by depositing the above charge generation material.

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

Examples (1) Synthesis Example of Charge Transport Material First Synthesis Example (Synthesis of N, N, N ′, N′-tetrakis (3-tolyl) -5-chloro-1,3-phenylenediamine) 5 3.6 g of -chloro-1,3-phenylenediamine, 21.8 g of iodotoluene, 6.9 g of potassium carbonate and 2 g of copper powder were added to 100 ml of nitrobenzene and the mixture was refluxed for 24 hours.

After the reaction, nitrobenzene and iodotoluene were removed by steam distillation, and the residue was washed with water and methanol.
Next, the residue was added to 900 ml of benzene, the water-soluble matter was filtered off, and the 1st fraction was taken with an activated alumina column chromatography developing solution (benzene-hexane 1: 1). Further, this fraction was separated by activated alumina column chromatography using benzene-hexene 1: 2 as a developing solution to obtain a 1st fraction. The solvent was distilled off, a part of it was dissolved in acetonitrile at room temperature, and the resulting crystal was used as a seed to crystallize from acetonitrile to give the title compound N, N, N ′,
N'-Tetrakis (3-tolyl) -5-chloro-1,3-phenylenediamine (Compound 1 of the invention) was obtained. The melting point of this compound was 112 to 113 ° C.

Second Synthesis Example (Synthesis of N, N, N ′, N′-tetrakis (3-tolyl) -5-nitro-1,3-phenylenediamine) 5-Nitroresorcinol (5-nitro-1,3- Benzenediol) 13.6g, m-toluidine 22.6g and iodine 0.5g
In the presence of, the reaction was carried out by refluxing in a nitrogen stream for 3 days. After the reaction, the mixture was cooled to room temperature and the resulting solid was added to 500 ml of methanol.
Washed with N, N'-bis (3-tolyl) -5-nitro-
1,3-Phenylenediamine was obtained. Then, this N, N'-
Bis (3-tolyl) -5-nitro-1,3-phenylenediamine 16.7 g, iodotoluene 21.8 g, potassium carbonate 9.7 g
Then, 2 g of copper powder was added to 100 ml of nitrobenzene, and the mixture was refluxed for 24 hours for reaction. After the reaction, nitrobenzene and iodotoluene were removed by steam distillation, and the residue was washed with water and methanol. Then, the residue was added to 900 ml of benzene, the water-soluble matter was filtered off, and the 1st fraction was taken with an activated alumina column chromatography developing solution (benzene-hexane 1: 1). Further, this fraction was added to benzene-hexane.
It was separated by activated alumina column chromatography using 1: 2 as a developing solution, and the 1st fraction was taken. The solvent was distilled off, a part of it was dissolved in acetonitrile at room temperature, and the resulting crystal was used as a seed to crystallize from acetonitrile to give the title compound N, N, N ′, N′-tetrakis (3-tolyl). −
5-Nitro-1,3-phenylenediamine (Compound 2 of the invention) was obtained. The melting point of this compound was 119 to 120 ° C.

Third Synthesis Example (Synthesis of N, N, N ′, N′-tetrakis (3-tolyl) -5-sulfo-1,3-phenylenediamine) Instead of 5-nitroresorcinol of the second synthesis example 16.8 g of 5-sulforesorcinol (3,5-dihydroxybenzenesulfonic acid) was used in the same manner as in the above-mentioned second synthesis example to prepare N, N'-bis (3-tolyl) -5-sulfo-
1,3-Phenylenediamine was obtained. This N, N'-bis (3
-Tolyl) -5-sulfo-1,3-phenylenediamine 9.3
g, iodotoluene 10.9g, potassium carbonate 5g and copper powder
1.2 g was added to nitrobenzene 50 ml, and the mixture was refluxed for 24 hours. Hereinafter, in the same manner as in the second synthesis example, the title compound N, N,
N ', N'-tetrakis (3-tolyl) -5-sulfo-1,3
-Phenylenediamine (Compound 3 of the invention) was obtained. The melting point of this compound was 133-134 ° C.

Fourth Synthesis Example (Synthesis of N, N, N ′, N′-tetrakis (3-tolyl) -5-cyano-1,3-phenylenediamine) Instead of 5-nitroresorcinol of the second synthesis example In the same manner as in the second synthesis example above, 11.9 g of 5-cyanoresorcinol (3,5-dihydroxybezonitrile) was used as N, N′-bis (3-tolyl) -5-cyano-1, 3-Phenylenediamine was obtained. This N, N'-bis (3-tolyl) -5-cyano-1,3-phenylenediamine 7.8 g, iodotoluene 10.9 g, potassium carbonate 5 g and copper powder 1.2 g
Was added to 50 ml of nitrobenzene and refluxed for 24 hours for reaction. Hereinafter, in the same manner as in the second synthesis example, the title compound N, N,
N ', N'-tetrakis (3-tolyl) -5-cyano-1,3
-Phenylenediamine (Compound 4 of the invention) was obtained. The melting point of this compound was 118 to 119 ° C.

Fifth Synthesis Example (Synthesis of N, N, N ′, N′-tetrakis (3-tolyl) -5-formyl-1,3-phenylenediamine) Instead of 5-nitroresorcinol of the second synthesis example 5-formylresorcinol (3,5-dihydroxybenzaldehyde) 12.1 g was used in the same manner as in the above second synthesis example to prepare N, N'-bis (3-tolyl) -5-formyl-1,3- Obtained phenylenediamine.

This N, N'-bis (4-tolyl) -5-formyl-1,3-
7.9 g of phenylenediamine, 10.9 g of iodotoluene, 5 g of potassium carbonate and 1.2 g of copper powder were added to 50 ml of nitrobenzene and refluxed for 24 hours for reaction. Thereafter, the title compound N, N, N ', N'-tetrakis (3-
Tolyl) -5-formyl-1,3-phenylenediamine (inventive compound 5) was obtained. The melting point of this compound is 120-1
It was 21 ° C.

Sixth Synthesis Example (Synthesis of N, N, N ′, N′-tetrakis (3-tolyl) -5-acetyl-1,3-phenylenediamine) Instead of 5-nitroresorcinol of the second synthesis example 13.4 g of 5-acetylresorcinol (3,5-dihydroxyacetophenone) was used in the same manner as in the above-mentioned second synthesis example, and N, N'-bis (3-tolyl) -5-acetyl-
1,3-Phenylenediamine was obtained. This N, N'-bis (3
-Tolyl) -5-acetyl-1,3-phenylenediamine
8.3 g, iodotoluene 10.9 g, potassium carbonate 5 g and copper powder 1.2 g were added to nitrobenzene 50 ml, and the mixture was refluxed for 24 hours for reaction. In the same manner as in the second synthesis example, the title compound N, N, N ′, N′-tetrakis (3-tolyl) -5-acetyl-1,3-phenylenediamine (the present compound 6)
Got The melting point of this compound was 122 to 123 ° C.

Seventh Synthesis Example (Synthesis of N, N, N ′, N′-tetrakis (3-tolyl) -5-carboxy-1,3-phenylenediamine) Of the above-mentioned second synthesis example, 5-nitroresorcinol Instead of 13.6 g of 5-carboxyresorcinol (3,5-dihydroxybenzenecarboxylic acid), N, N'-bis (3-tolyl) -5-carboxy-1 was prepared in the same manner as in the second synthesis example above. , 3-Phenylenediamine was obtained. This N, N′−
Bis (3-tolyl) -5-carboxy-1,3-phenylenediamine 8.3 g, iodotoluene 10.9 g, potassium carbonate 5
g and 1.2 g of copper powder were added to 50 ml of nitrobenzene and reacted for 24 hours under reflux. Thereafter, the title compound N, N, N ', N'-tetrakis (3-tolyl) is obtained in the same manner as in the second synthesis example.
-5-carboxy-1,3-phenylenediamine (inventive compound 7) was obtained.

The melting point of this compound was 143-144 ° C.

Eighth Synthesis (Synthesis of N, N, N ′, N′-tetrakis (3-tolyl) -5-ethoxycarbonyl-1,3-phenylenediami) Of the 5-nitroresorcinol of the second synthesis example, N, N'-bis (3-tolyl) -5-ethoxycarbonyl-1,3-phenylenediamine was obtained in the same manner as in the above second synthetic example by using 16.0 g of ethyl 3,5-dihydroxy-benzoate instead. Got This N, N'-bis (3-tolyl) -5-ethoxycarbonyl-1,3-phenylenediamine 9.0 g, iodotoluene 10.9 g, potassium carbonate 5 g and copper powder 1.2 g
Was added to 50 ml of nitrobenzene and refluxed for 24 hours for reaction. Hereinafter, in the same manner as in the second synthesis example, the title compound N, N,
N ', N'-tetrakis (3-tolyl) -5-ethoxycarbonyl-1,3-phenylenediami (the present compound 8)
Got

The melting point of this compound was 136-137 ° C.

(2) Preparation of Electrophotographic Photoreceptor Preparation of Single-Layer Electrophotographic Photoreceptor N, N′-di (3,5-dimethylphenyl) perylene-3,4,9,10-tetracarboxydiimide 8 as charge generating material
Parts by weight, 100 parts by weight of the compound of the present invention synthesized in Synthesis Examples 1 to 8 as a charge transport material, and poly- as a binder resin.
100 parts by weight of (4,4'-cyclohexylidenediphenyl) carbonate (polycarbonate Z200, manufactured by Mitsubishi Gas Chemical Co., Inc.) and a predetermined amount of tetrahydrofuran are mixed and dispersed in an ultrasonic disperser to prepare a single-layer type photosensitive layer. A coating liquid was prepared. This coating solution is applied on an aluminum tube with an outer diameter of 78 mm and a length of 340 mm, and then dried by heating at 100 ° C for 30 minutes in the dark, and a drum-type electrophotographic photoconductor having a single-layer type photosensitive layer with a thickness of 24 μm. Created the body.

Preparation of Laminated Electrophotographic Photoreceptor 100 parts by weight of polyvinyl butyral (manufactured by Sekisui Chemical Co., Ltd., trade name Eslec BL1) as a binder resin, 100 parts by weight of oxotitanyl phthalocyanine as a charge generating material, and a predetermined amount of tetrahydrofuran in a ball mill. Preparation, 24
The mixture was stirred and mixed for a period of time to prepare a coating solution for the charge generation layer, which was coated on an aluminum drum by a dipping method.
A film thickness of 0.5 is obtained by heating and drying at 0 ° C for 30 minutes and curing.
A charge generation layer of μm was formed.

Then, 100 parts by weight of a polycarbonate resin (trade name, Iupilon, manufactured by Mitsubishi Gas Chemical Co., Inc.) 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 charge transport layer coating solution. This coating solution is applied to the surface of the charge generation layer by a dipping method, and the temperature is 120 °
The film was dried with hot air for 30 minutes to form a charge transport layer having a thickness of about 20 μm to prepare a laminated electrophotographic photoreceptor.

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

(3) Evaluation of electrophotographic photoconductor Single layer type electrophotoconductor (measurement of initial surface potential V _SP ) Each of the above single layer type electrophotographic photoconductors was subjected to an electrostatic copying tester (Gentec Cynthia 30M manufactured by Gentec). ), The surface is positively charged, and the surface potential V _{SP of} each photoconductor is
(V) was measured.

(Measurement of half-dose exposure amount and residual potential) Each of the electrophotographic photoconductors in the above charged state was measured by a halogen lamp (exposure intensity 0.92 mW
/ cm ² ), the half-exposure amount E _1/2 (μJ / cm ² ) was calculated by determining the time until the surface potential V _SP became 1/2.

Further, the surface potential after 0.15 seconds has elapsed from the start of the exposure is _defined as the residual potential V _rp (V).

Laminated electrophotographic photoreceptor Monochromatic light obtained by passing Xe lamp light through a spectroscope as an exposure light source (λ = 780 nm, exposure intensity = 10 μW / cm ² , exposure time = 1 second)
Each laminated electrophotographic photosensitive member is exposed using
The surface potential after a lapse of seconds is measured as the residual potential V _rp . Others were measured in the same manner as in the case of the single-layer type electrophotographic photosensitive member.

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” is the initial characteristic before light irradiation, and “After exposure” is the characteristic after irradiation with white light containing 400 lux of ultraviolet light for 40 minutes using a white fluorescent lamp. Show.

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

[Effects of the Invention] As described above, the compound for a charge transport material of the present invention is excellent in photostability because it is protected by substituting the position 5 of the central benzene ring with an electron-withdrawing group. By using the charge transport material, an electrophotographic photoreceptor having excellent light stability can be obtained.

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Claims (2)

[Claims] 1. The following general formula [I]: (In the formula, R ¹ , R ² , R ³ and R ⁴ are the same or different and are an alkyl group, an alkoxyl group, a halogen atom, an amino group or N
A substituted amino group, l, m, o and p are the same or different and each represents an integer of 0 to ⁵ , and R ⁵ represents an electron-withdrawing group). 2. An electrophotographic photoreceptor comprising a conductive layer and a photosensitive layer containing the m-phenylenediamine compound according to claim 1 provided on the conductive substrate.