JPH0413775A - M-phenylenediamine compound and electrophotograghic photoreceptor containing the same - Google Patents

Abstract

NEW MATERIAL:The compound of formula I (R<1> to R<4> are alkyl, alkoxyl, halogen, amino or N-substituted amino; l, m, o and p are 0-5; R<5> and R<6> are alkyl, alkoxyl, halogen, amino, N-substituted amino, allyl or aryl; q and r are 0 or 1 provided that q and r are not 0 at the same time). EXAMPLE:N,N,N',N'-tetrakis(3-tolyl)-4,6-dichloro-1,3-phenylenediamine. USE:A charge-transfer material in electrophotographic photoreceptor. PREPARATION:The objective compound can be produced by reacting a resorcinol derivative of formula II with an aniline derivative of formula III in the presence of iodine in nitrogen stream and reacting the resultant phenylenediamine compound of formula IV with an idodobenzene derivative of formula V in the presence of potassium carbonate and copper powder in a solvent such as nitrobenzene.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] 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, organic photoreceptors have been used as electrophotographic photoreceptors in image forming devices such as copying machines because they have excellent processability, are advantageous in terms of manufacturing costs, and have a large degree of freedom in functional design. There is.

Further, when forming a copy image using an electrophotographic photoreceptor, the Carlson process is widely used. The Carlson process consists of a charging process in which a photoreceptor is uniformly charged by corona discharge, an exposure process in which an original image is exposed to the charged photoreceptor to form an electrostatic latent image corresponding to the original image, and an electrostatic latent image is formed in the electrostatic latent image. A development process in which a toner image is formed by developing with a developer containing toner, a transfer process in which the toner image is transferred to a base material such as paper, a fixing process in which the toner image transferred to the base material is fixed, and a transfer process. After the process, a cleaning process is included to remove toner remaining on the photoreceptor. To form high quality images in this Carlson process,
Electrophotographic photoreceptors are required to have excellent charging characteristics and photosensitive characteristics, and to have a low residual potential after exposure.

One of the means to achieve these properties is the selection of appropriate charge transport materials. Many compounds such as polyvinylcarbazole, oxadiazole compounds, pyrazoline compounds, and hydrazone compounds have been proposed as the charge transport material.

[Problem 8 to be Solved by the Invention] However, the charge transport material described above has a relatively low drift mobility indicating charge transport ability. Further, since drift mobility has a large dependence on electric field strength, there is a problem that charge movement is small in a low electric field and residual potential is difficult to escape. Furthermore, there are problems such as easy deterioration due to irradiation with ultraviolet light.

To solve these problems, N,N,NN''-tetraphenyl-1,3-phenylenediamine is an m=phenylenediamine-based compound that has low dependence of drift mobility on electric field and good compatibility with resin. has been proposed (Japanese Patent Application No. 62-301703).This m-phenylenediamine compound has good light resistance against ultraviolet light and exhibits stable characteristics even when used in an actual copying machine.However, When a copying machine breaks down and is exposed to light for a long time or at high temperatures, there is a problem in that irreparable damage occurs.

The present invention is intended to solve the above-mentioned problems, and aims to provide an m-phenylenediamine compound that has better light resistance and excellent photostability, and an electrophotographic photoreceptor using the same.

E Means and Actions for Solving Problems In general, the cause of deterioration of photoreceptor characteristics due to photodeterioration is the formation of impurities in the photoreceptor that act as traps for the charge transport material. In the case of m-phenylenediamine-based compounds, a ring-closing reaction occurring between the central benzene ring and other phenyl groups can be considered as such a photodegradation reaction. This reaction is thought to occur more easily because the electron density of the phenylenediamine compound molecule is biased towards the central benzene ring. In particular, the 4.6-position of the central benzene ring has a high electron density, making the molecular structure susceptible to attacks from oxidizing substances such as oxygen. Therefore, we thought that it is possible to suppress reactivity and improve stability by substituting and protecting this part with a substituent, and as a result of various experiments, we found that this position could be replaced with an alkyl group, an alkoxyl group, or an amino group. By substituting with a predetermined substituent such as a group, an N-[substituted amino group, an allyl group, or an aryl group, the photostability of the photoreceptor can be effectively improved without impairing charge transport properties such as drift mobility. I found out.

Therefore, the m-phenylenediamine compound of the present invention has the following general formula [■]: - represents a substituted amino group, J, m, o, p are the same or different and represent an integer of 0 to 5; R5R6 is the same or different and represents an alkyl group, an alkoxyl group, a halogen atom, an amino group, an N-substituted amino group, allyl group, aryl group, and q and r represent 0 or 1. However, q
.

r must not be 0 at the same time. ) It is a m-fuynylenediamine type compound represented by

In the m-phenylenediamine compound, at least one of the 4.6 positions of the central benzene ring is protected with a substituent (alkyl group, alkoxyl group, halogen atom, amino group, N-substituted amino group, allyl group, aryl group). This makes it less susceptible to attack from oxidizing substances, significantly suppresses photodegradation reactions, and improves stability against light.

In addition, the photoreceptor containing the m-phenylenediamine compound suffers less damage than conventional photoreceptors when exposed to light for long periods of time or at high temperatures, and has excellent photostability. There is.

[Preferred Embodiment of the Invention] In the m-)unilenediamine compound of the present invention represented by the general formula [N], the alkyl group among R' and R'R3R4 is a methyl group.

Examples include lower alkyl groups having 1 to 6 carbon atoms such as ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, and hexyl group.

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

Note that R1, R2, R3, and R4 may be the same or different from each other.

Moreover, as R5 and R', an alkyl group, an alkoxyl group, a halogen atom, an amino group, an N-substituted amino group, an allyl group, and an aryl group are suitable.

The above Rs and Rh may be the same or different from each other. Furthermore, it is necessary that at least one of Rs and Rh be substituted, and it is more preferable that both are substituted.

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

The compound represented by the above formula [11] of the present invention can be synthesized by various methods, and for example, can be synthesized by the following series of reaction formulas [A] or reaction formula [B].

Reaction formula [A]: (blank below) Reaction formula [B]: ■ In formula c, R" and R" are the same or different and represent an alkyl group, an alkoxy group, a halogen atom, an amino group, an N-
Indicates a substituted amino group. That is, in the reaction step [A] above, formula (1)
The resorcinol derivative represented by the formula (2) and the aniline derivative represented by the formula (2) are refluxed and reacted together with iodine under a nitrogen stream to obtain a phenylenediamine compound represented by the above formula (3). Then, by reacting the compound of the above formula G) with the iodobenzene derivative represented by the above formula (4) in a solvent (for example, nitrobenzene) in the presence of potassium carbonate and copper powder, The m-phenylenediamine compound of the present invention in which R2 and R4 are the same as R1 and R3 is obtained.

Here, substituents R5 and R6 such as alkyl groups in the compound represented by general formula [I] are as described above, for example,
It is possible to introduce resorcinol in advance,
R'' (i.e., R2 in general formula [1], R
4) is introduced into aniline in advance, and furthermore, the substituent R”
(That is, R1.R3 in general formula [I]) can be introduced into iodobenzene in advance.

On the other hand, as shown in the above reaction formula [B], the phenylenediamine derivative of formula (5) and the iodobenzene derivative of formula (6) are reacted by refluxing both potassium carbonate and copper powder in a solvent (for example, nitrobenzene). By doing so, it is possible to synthesize the m-phenylenediamine compound of the present invention in which R1 to R4 in general formula [1] are all the same substituents.

In addition, in order to synthesize a compound of the present invention other than the compound obtained by the above reaction formula [A] or [B], for example, a compound in which R1 to R4 are all different substituents, the above reaction formula [A]
Alternatively, a method may be mentioned in which the molar ratio of the starting materials in [B] is appropriately adjusted and each phenyl group having substituents R1 to R4 is introduced stepwise. Furthermore, after introducing a phenyl group having no substituents, substituents R1 to R4R5 and R6
may be introduced sequentially.

The compound represented by the general formula [I] of this invention 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 diphenoginone derivatives such as 2°6-dimethyl-2°,6°-ditert-dibutyldiphenoquinone, malononitrile, thiobilane compounds, tetracyanoethylene, 2.4.8-trini Examples include drothioxanthone, 3,4,5.7-tetranitro-9-fluorenone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride, and the like.

Examples of electron-donating compounds 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, pyrazoline compounds such as 1-phenyl-3-(p-dimethylaminophenyl)pyrazoline, hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds, inoxazole compounds Examples include nitrogen-containing cyclic compounds such as , thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, and triazole compounds, and fused polycyclic compounds.

These charge transport materials may be used alone or in combination of two or more. Note that when using a charge transporting material having film-forming properties such as polyvinylcarbazole, a binder resin is not necessarily required.

The compound represented by the above formula CI] can be applied to both so-called single layer type and laminated type electrophotographic photoreceptors.

In order to obtain a single-layer type electrophotographic photoreceptor, a photosensitive layer containing a charge transporting material represented by the above formula [1], a charge generating material, a binder resin, etc. is placed on a conductive substrate. Just form it.

In addition, in order to obtain a laminated 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 charge generation layer is coated with the charge generation material. - A charge transport layer containing a compound represented by formula [1] and a binder resin may be formed. Further, contrary to the above, a charge transport layer similar to the above may be formed on the conductive substrate, and then a charge generation layer containing a charge generation material may be formed by means such as vapor deposition or coating. Furthermore, the charge generation layer may be formed by coating a charge generation material and a charge transport material dispersed in a binder resin.

Examples of the charge generating material include selenium, selenium-
Tellurium, amorphous silicon, pyrylium salt, azo pigment, disazo pigment, anthanthrone pigment, phthalocyanine pigment, indigo pigment, triphenylmethane pigment, threne pigment, toluidine pigment, pyrazoline pigment, perylene pigment , quinacridone pigments, pyrrole pigments, and the like, which may be used singly or in combination of two or more so as to have an absorption wavelength range in a desired region.

Furthermore, various resins can be used as the binder resin in the photosensitive layer, charge generation layer, and charge transport layer. For example, styrene polymers, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, acrylic polymers, styrene-acrylic copolymers, polyethylene, ethylene-vinyl acetate copolymers. , chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer,
Thermoplastic resins such as polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, silicone resin, epoxy resin, phenol resin, urea resin, melamine resins, other crosslinkable thermosetting resins,
and photocurable resins such as epoxy acrylate and urethane acrylate. These binder resins may be used alone or in combination of two or more.

Further, a solvent is used when forming the charge generation layer and the charge transport layer by a coating method. Various organic solvents can be used as this solvent, including alcohols such as methanol, ethanol, isopropanol, butanol, aliphatic/hydrocarbons such as n-hexane, octane, and cyclohexane, and benzene. , aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride, and chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, and cyclohexanone. Examples include ketones such as ethyl acetate, esters such as methyl acetate, dimethyl formaldehyde, dimethyl formamide, dimethyl sulfoxide, etc., and these solvents may be used alone or in combination of two or more.

Further, in order to improve the sensitivity of the charge generation layer, a known sensitizer such as terphenyl, halonaphthoquinones, acenaphthylene, etc. may be used together with the charge generation material. Furthermore, the dispersibility of electrical transport materials and charge generating materials,
Surfactants, leveling agents, etc. may be used to improve dyeability.

As the conductive base material, various conductive materials can be used, such as aluminum, copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, Examples include simple metals such as indium, stainless copper, and brass, plastic materials on which the above metals are vapor-deposited or laminated, and glass coated with aluminum iodide, tin oxide, indium oxide, and the like. The above-mentioned conductive base material may be in the form of a sheet or a drum, as long as the base material itself has conductivity or the surface of the base material has conductivity. The base material preferably has sufficient mechanical strength during use.

The compound of the present invention as the charge transporting material and the binder resin can be used in various proportions within the range that does not inhibit charge transport and does not cause crystallization. On the other hand, it is preferable to use 125 parts by weight to 200 parts by weight of the compound represented by the general formula [I].

Further, the charge transport layer containing the compound represented by the general formula [1] is preferably formed to have a layer thickness of about 2 to 100 μm, particularly about 5 to 30 μm.

When the charge generating material described above is used together with a binder resin, the charge generating material and the binder resin can be used in various ratios, but from 1 to 150 parts by weight of the binder resin per 10 parts by weight of the charge generating material. It is desirable to use the ratio of

Further, the thickness of the charge generation layer containing the above charge generation material can be arbitrarily selected, but the thickness is 0.01 to 20.
It is desirable to form the layer to a thickness of approximately 0.1 to 10 μm. Furthermore, the thickness of the single-layer type photosensitive layer in which the compound represented by the general formula [1] and the charge-generating material are present in a single layer can be arbitrarily selected;
In particular, it is preferable to form the layer to a thickness of about 5 to 30 μm.

In addition, in a single-layer electrophotographic photoreceptor, between the base material and the photosensitive layer, and in a laminated 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, as long as it does not impede the characteristics of the photoreceptor. A layer may be formed.

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

Hereinafter, the present invention will be explained in detail with reference to Examples.

[Example] (1) Synthesis example of charge transport material First synthesis example (N, N, N', N'-tetrakis(3-tolyl)-
Synthesis of 4,6-dichloro-1,3-phenylenediamine) 15.7 g of 4.6-dichlororesorcinol and 22.6 g of m-)luidine were combined in the presence of 0.5 g of iodine in a nitrogen stream for 3 days. The reaction was carried out under reflux to form N,N'-bis(3-
Tolyl)-4,6-dichloro-1,3-phenylenediamine was obtained. Next, this N,N'-bis(3-tolyl)-4,6-dichloro-1,3-phenylenediamine 9
．． In the presence of 5.0 g of potassium carbonate and 1.5 g of copper powder, 1.0 g of nitrobenzene and 10.9 g of iodotoluene were added.
The reaction was carried out under reflux for 24 hours in the 00m layer to form the title compound N,N,N',N'-tetrakis(3-tolyl)-4.
,6-dichloro-1,3-phenylenediamine (compound 1 of the present invention) was obtained. The reactions in the above synthesis steps were based on the series of reaction formulas [A] described above.

The melting point of this compound was 110-111''C.

Second synthesis example (N, N, N', N'-tetrakis(3-tolyl)-
Synthesis of 4-methyl-1,3-phenylenediamine) The title compound was synthesized according to the series of reaction formulas [B] described above.

3.1 g of 4-methylphenylenediamine and 21.8 g of m-iodotoluene were dissolved in 100 mJ of nitrobenzene in the presence of 6.9 g of potassium carbonate and 1.5 g of copper powder.
The reaction was carried out under reflux for 4 hours, and the title compound N, N, N'
, N'-tetrakis(3-tolyl)-4-methyl-1,
3-phenylenediamine (invention compound 2) was obtained.

The melting point of this compound was 90-92°C.

Third synthesis example (N, N, N', N'-tetrakis(3-tolyl)-
Synthesis of 4-methoxy-1,3-phenylenediamine) Same as in the first synthesis example above using 12.3 g of 4-methoxyresorcinol instead of 4,6-cycloresorcinol in the first synthesis example above. , N, N'-bis(3
-Tolyl)-4-methoxy-1,3-phenylenediamine was obtained. This N.

No-bis(3-tolyl)-4-methoxy-1゜3-phenylenediamine 8.0g and iodotoluene 10.9g
were subjected to a reflux reaction for 24 hours in 50 mJ of nitrobenzene in the presence of 5.0 g of potassium carbonate and 1.5 g of copper powder. Hereinafter, in the same manner as in the first synthesis example, the title compounds N, N
,N',Ntetrakis(3-tolyl)-4-methoxy-
1°3-phenylenediamine (Compound 3 of the present invention) was obtained.

The melting point of this compound was 114-115°C.

Fourth synthesis example (N, N, N', N'-tetrakis(3-tolyl)-
Synthesis of 4-amino-1,3-phenylenediamine) Same as in the first synthesis example above, using 11°Og of 4-amylturcinol instead of 4,6-cycloresorcinol in the first synthesis example above. Then, NN"-bis(3-tolyl)-4-amino-1,3 phenylenediamine was obtained.

This N,N'-bis(3-tolyl)-4-amino-1
, 7.6 g of 3-phenylenediamine and 1 iodotoluene
0.9g, potassium carbonate 5.0g, copper powder 1.5g
The reaction was carried out under reflux for 24 hours in 50 mj of nitrobenzene. Hereinafter, the title compound N,N,N",N'-tetrakis(3-tolyl)-6-amino-1,3-phenylenediamine (invention compound 4) was obtained in the same manner as in the first synthesis example. .

The melting point of this compound was 121-122°C.

Fifth synthesis example (N, N, N', N'-tetrakis(3-tolyl)-
Synthesis of 4-allyl-1,3-phenylenediamine) Same as in the first synthesis example above, using 13.2 g of 4-amylturcinol instead of 4,6-cycloresorcinol in the first synthesis example above. Then, N.

No-bis(3-tolyl)-4-allyl-1,3-phenylenediamine was obtained. This N,N”-bis(3-tolyl)-4-allyl-1,3-phenylenediamine 8.2
g and 10.9 g of iodotoluene, and 5.0 g of potassium carbonate.
0 g, 50 m of nitrobenzene in the presence of 1.5 g of copper powder
The reaction mixture was refluxed for 24 hours in a vacuum cleaner. Hereinafter, the title compound N,N,N°,N'-tetrakis(3-tolyl)-4-allyl-1,3-phenylenediamine (invention compound 5) was obtained in the same manner as in the first synthesis example. . The melting point of this compound was 115-116°C.

Sixth synthesis example (N, N, N', N'-tetrakis(3-tolyl)-
Synthesis of 4-phenylresorcinol-1,3-phenylenediamine) Synthesis of the first synthesis example above using 16.4 g of 4-phenylresorcinol instead of 4,6-cycloresorcinol in the first synthesis example above. Similarly, N,N'-bis(3
-tolyl)-4-phenyl-1,3-phenylenediamine was obtained. This N, N-bis(3-tolyl)-4-
9.1 g of phenyl-1,3-phenylenediamine and 10.9 g of iodotoluene were dissolved in 50 mj of nitrobenzene in the presence of 5.0 g of potassium carbonate and 1.5 g of copper powder.
The mixture was refluxed for 4 hours to react. Hereinafter, the title compound N, N, N', N-tetrakis (3
-Tolyl)-4-phenyl-1°3-phenylenediamine (Compound 6 of the present invention) was obtained. The melting point of this compound is 12
The temperature was 3-124°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 Part by weight, the above Synthesis Example 1 as a charge transport material
100 parts by weight of the compound of the present invention synthesized in steps 6 to 6, 100 parts by weight of poly-(4゜4゛-cyclohexylidene diphenyl) carbonate (manufactured by Mitsubishi Gas Chemical Co., Ltd., polycarbonate Z200) as a binder resin, and a predetermined amount of tetrahydrofuran. The mixtures were mixed and dispersed using an ultrasonic disperser to prepare a coating solution for a single-layer photosensitive layer. This coating liquid was applied to an outer diameter of 78 m.
+* After coating it on an aluminum tube with a length of 340III11, it was heated and dried in a dark place at 100°C for 30 minutes to create a drum-shaped electrophotographic photoreceptor having a single-layer photosensitive layer with a thickness of 24 μm. .

Preparation of Laminated Electrophotographic Photoreceptor 100 parts by weight of polyvinyl butyral (manufactured by Miki Kagaku Co., Ltd., trade name: Sletsku BLI) as a binder resin, 100 parts by weight of oxotitanylphthalocyanine as a charge generating material, and a predetermined amount of tetrahydrofuran were mixed in a ball mill. A coating liquid for the charge generation layer is prepared by stirring and mixing for 24 hours, and this prepared liquid is applied to an aluminum drum by the dipping method, and is cured by drying with hot air at 110°C for 30 minutes to obtain a film thickness of 0.5 μm. A charge generation layer was formed.

Next, 100 parts by weight of a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: Niepiron) as a binder resin, 100 parts by weight of each compound synthesized in Synthesis Examples 1 to 6 above as a charge transport layer, and a predetermined amount of toluene. were stirred and mixed using a homomixer to prepare a charge transport layer coating solution. This coating liquid was applied to the surface of the charge generation layer by dipping and drying, and 1
By drying with hot air at 20℃ for 30 minutes, the film thickness becomes 20μ.
A layered electrophotographic photoreceptor was prepared by forming a charge transport layer of m.

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

(3) Evaluation of electrophotographic photoreceptor Single-layer electrophotographic photoreceptor (measurement of initial surface potential V3) Each of the above-mentioned single-layer electrophotographic photoreceptors was tested using an electrostatic copying tester (manufactured by Gientic Co., Ltd., Gientic Cynthia 30M). The surface potential of each photoreceptor is VS by positively charging its surface.
P(V) was measured.

(Measurement of half-decreased exposure amount and residual potential) Each electrophotographic photoreceptor in the above-mentioned charged state was exposed to a halogen lamp (exposure intensity 0.9
2 mW/cd), and the surface potential VSP was 1
Find the time until it reaches 72, and calculate the half-decreased exposure amount El/2 (
μJ/cm2) was calculated.

Further, the surface potential after 0.15 seconds had passed after the start of the exposure was defined as the residual potential V, (V).

Monochromatic light (λ - 780 nm, exposure intensity - 10 μW/cd,
Each laminated electrophotographic photoreceptor was exposed using an exposure time of -1 second), and the surface potential after 0.5 seconds had passed after exposure was determined as residual potential V1. The measurements were taken after closing. Other measurements were carried out in the same manner as in the case of the single-layer electrophotographic photoreceptor.

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

Table 1 (Single-layer electrophotographic photoreceptor) In Tables 1 and 2, "before exposure" refers to the initial characteristics before light irradiation, and "after exposure" refers to the initial characteristics before light irradiation, using a white fluorescent lamp, including ultraviolet rays of 400 lux. The characteristics after irradiation with white light for 40 minutes are shown.

As shown in Tables 1 and 2 above, all of the photoreceptors using the compound for charge transport materials of the present invention have an initial surface potential of VS
P, half-reduced exposure amount E I/2, residual potential V1. It can be seen that the fluctuations in values before and after exposure in both cases are smaller than in the comparative example, indicating excellent stability against light.

E. Effects of the Invention As described above, the compound for charge transport materials of the present invention has excellent photostability because the 4.6 position of the central benzene ring is protected by substitution with a predetermined substituent. , and by using the charge transport material, an electrophotographic photoreceptor with excellent photostability can be obtained.

Table 2 (Laminated electrophotographic photoreceptor)

Claims (2)

[Claims] (1) The following general formula [I]: ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] (In the formula, R^1, R^2, R^3, R^4 are the same or different, and are alkyl group, alkoxyl group, halogen atom, amino group, N-substituted amino group, l, m, o, p
are the same or different and represent integers from 0 to 5, R^5,
R6 is the same or different and represents an alkyl group, an alkoxyl group, a halogen atom, an amino group, an N-substituted amino group, an allyl group, or an aryl group, and q and r represent 0 or 1. However, q and r must not be 0 at the same time. ) A m-phenylenediamine compound represented by: (2) An electrophotographic photoreceptor, characterized in that a photosensitive layer containing the m-phenylenediamine compound according to claim 1 is provided on a conductive substrate.