JP3530702B2 - Electrophotographic photoreceptor using dithiomaleimide derivative - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention was used di thiomalate imide derived material, for example an electrostatic copying machine, a facsimile, an electrophotographic photoreceptor used in an image forming apparatus such as a laser beam printer.

[0002]

2. Description of the Related Art Electrophotographic photoreceptors made of various materials are used in image forming apparatuses such as copiers, facsimiles and laser printers using the Carlson process. One is an inorganic photoreceptor using an inorganic material such as selenium in the photosensitive layer, and the other is an organic photoreceptor (OPC) using an organic material in the photosensitive layer. Among them, the organic photoconductor has many advantages such as being cheaper than the inorganic photoconductor, having high productivity, and being non-polluting. Therefore, extensive research has been conducted.

Most organic photoconductors are laminated type photoconductors in which a charge generation layer and a charge transport layer are laminated, that is, so-called function-separated type photoconductors. So-called single-layer type photoconductors dispersed in layers are also known. The charge transport agents used in these photoconductors are required to have high carrier mobility, but most of the charge transport agents having high carrier mobility have hole transporting properties, and therefore are not put to practical use. From the viewpoint of mechanical strength, the existing organic photoreceptor is limited to a negative charging type laminated organic photoreceptor having a charge transport layer as the outermost layer. However, since the negative charging type organic photoconductor uses negative corona discharge, a large amount of ozone is generated, which causes problems such as pollution of the environment and deterioration of the photoconductor.

Therefore, in order to eliminate such a defect, use of an electron transfer agent as a charge transfer agent has been studied. For example, JP-A-1-206349 has a diphenoquinone structure or a benzoquinone structure. It has been proposed to use the compounds as electron transport agents for electrophotographic photoreceptors. In addition, JP-A-5-14281
Japanese Patent Laid-Open No. 2 (1994) proposes to use a benzenetetracarboxylic acid diimide compound as an electron transfer material for an electrophotographic photoreceptor.

[0005]

However, in general, conventional electron transfer agents such as diphenoquinone derivatives, benzoquinone derivatives, and benzenetetracarboxylic acid diimide compounds are difficult to match with charge generation agents, and electron transfer from charge generation agents is difficult. Insufficient electron injection into the agent. Further, since such an electron transfer material has a poor compatibility with the binder resin and a hopping distance becomes long, electron transfer is unlikely to occur in a low electric field. Therefore, the conventional photoconductor containing an electron transfer material has a problem that the residual potential becomes high and the sensitivity is low, as is clear from the photosensitivity test described in Examples described later.

Further, as described above, most of the organic photoconductors currently in practical use are provided with a laminated type photosensitive layer, but in comparison with this, a photoconductor provided with a single layer type photosensitive layer. Has a number of advantages in that it has a simple structure and is easy to manufacture, and that it suppresses the occurrence of coating defects and improves optical characteristics.
In addition, in a photoconductor provided with such a single-layer type photoconductive layer, one photoconductor is positively charged or negatively charged by using an electron transfer agent and a hole transfer agent in combination as a charge transfer agent. Although it can be used for both, and the application range of the photoconductor may be expanded, the above-mentioned conventional electron transfer agent has a problem that it interferes with electron and hole transfer due to interaction with the hole transfer agent. For this reason, a photoreceptor provided with such a single-layer type photosensitive layer has not been widely put into practical use.

An object of the present invention is to solve the technical problems described above, it is to provide an electrophotographic photosensitive member sensitive than traditional.

[0008]

In order to solve the above-mentioned problems, an electrophotographic photoreceptor of the present invention comprises a photosensitive layer on a conductive substrate.
And the photosensitive layer has the general formula (1):

[0009]

[Chemical 4]

[In the formula, R ¹ and R ² are the same or different and each represents an aryl group which may have a substituent. ]
Of containing a dithiomaleimide derivative represented by
It is characterized in that an optical layer is provided . The above general formula
The dithiomaleimide derivative of the present invention represented by (1) has good compatibility with the binder resin and is uniformly dispersed in the photosensitive layer, so that the hopping distance of electrons is short and particularly in a low electric field. It has excellent electron-transporting property and excellent matching with a charge generating agent. Therefore, by using such derivative (1) as an electron-transporting agent in an electrophotographic photosensitive member, a highly sensitive photosensitive member can be provided. can do.

[0011] dithio maleimide induction of the general formula (1) utilizes the high electron transport capability, the solar cell can be used in applications such as EL elements.

The photosensitive layer containing the above dithiomaleic acid imide derivative (1) has an excellent electron transporting property in a low electric field, and at the same time, the rate of recombination of electrons and holes in the layer is reduced, resulting in an apparent charge. As a result of the generation efficiency approaching the actual value, the sensitivity of the photoreceptor is improved. In addition, the residual potential of the photoconductor also becomes low, and the stability and durability upon repeated exposure are improved. In particular, the dithiomaleimide derivative (1) inhibits the transport of electrons and holes and does not interact with the hole transfer agent, so that the single layer type in which the hole transfer agent is contained in the same layer is used. When it is used for the photosensitive layer of No. 1, a photosensitive member having higher sensitivity can be constructed. Therefore, in the electrophotographic photosensitive member of the present invention, it is more preferable that the photosensitive layer is a single layer type photosensitive layer containing a hole transfer agent in the same layer .

Further, the photosensitive layer is -0.8 to -1.4V.
When the electron transfer agent having the redox potential of 1 is contained, the sensitivity of the photoreceptor is further improved. This is because the electron transfer agent functions to extract an electron from the charge generating agent and transfer it to the dithiomaleimide imide derivative (1), so that the electron is injected from the charge generating agent to the dithiomaleimide derivative (1). Is supposed to be even smoother.

Particularly, dithiomaleic acid imide derivative
Considering the compatibility with (1), etc., the general formula (2):

[0015]

[Chemical 5]

[Wherein, R ^A , R ^B , R ^C and R ^D are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a cycloalkyl group or an amino group. ] A diphenoquinone derivative represented by the general formula (3):

[0017]

[Chemical 6]

[Wherein R ^E , R ^F , R ^G and R ^H
Are the same or different and are hydrogen atom, alkyl group, alkoxy group, aryl group, aralkyl group, cycloalkyl group.
Or an amino group which may have a substituent. ] It is preferable to use a benzoquinone derivative represented by

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION First, the dithiomaleic acid imide derivative (1) used in the electrophotographic photosensitive member of the present invention will be described in detail. In the dithiomaleimide derivative (1) represented by the general formula (1), examples of the aryl group corresponding to the groups R ¹ and R ² include phenyl, tolyl, xylyl, biphenylyl, o-terphenyl, naphthyl,
Examples include anthryl and phenanthryl.

The aryl group may have a substituent, and as the substituent, an alkyl group, an aralkyl group,
Examples thereof include an alkoxy group, an alkanoyl group, a halogen atom, an aryl group and an alkoxycarbonyl group.
Examples of the alkyl group include methyl, ethyl, n-
Propyl, isopropyl, n-butyl, isobutyl, s
Examples thereof include groups having 1 to 6 carbon atoms such as -butyl, t-butyl, pentyl and hexyl.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine. As an alkoxy group,
For example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, s-butoxy, t-butoxy, pentyloxy, hexyloxy and the like have 1 carbon atom.
~ 6 alkoxy groups. The aralkyl group is, for example, an aralkyl group having an alkyl moiety having 1 to 6 carbon atoms in the alkyl moiety such as benzyl, 1-phenylethyl, 3-phenylpropyl, 4-phenylbutyl, 5-phenylpentyl, and 6-phenylhexyl. Can be given.

The alkoxycarbonyl group has 1 to 6 carbon atoms in the alkoxy moiety such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, t-butoxycarbonyl, pentyloxycarbonyl, and hexyloxycarbonyl. There is an alkoxycarbonyl group.

Examples of the alkanoyl group include alkanoyl groups having 1 to 6 carbon atoms such as acetyl, propionyl, butyryl, isobutyryl, pentanoyl, t-butylcarbonyl and hexanoyl. Examples of the aryl group include the same groups as described above. Further, the alkyl group and aryl group may have a substituent, and examples of the substituent of the alkyl group include the above halogen atoms. Examples of the substituent of the aryl group include the above alkyl groups and halogen atoms.

Specific examples of the dithiomaleimide derivative (1) represented by the general formula (1) include, for example, the following formula (1-1)
The compounds represented by (1-6) are mentioned.

[0025]

[Chemical 7]

[0026]

[Chemical 8]

The above-mentioned dithiomaleic acid imide derivative (1)
Can be synthesized, for example, according to the following reaction schemes I and II. Reaction formula I

[0028]

[Chemical 9]

[In the formula, R is the same as defined above. This reaction is carried out by reacting the chlorinated maleimide derivative represented by the formula (4) and rubeanic acid (5) in the absence of solvent or in a suitable solvent, to give the dithiomaleine used in the photoreceptor of the present invention. The acid imide derivative (1) is obtained. At that time, when a tertiary amine is added, chlorine produced as a by-product can be removed from the reaction system, so that the reaction is accelerated.

Examples of the tertiary amine include triethylamine, tributylamine, pyridine, pyrimidine, morpholine and lutidine. Reaction is 4
It may be carried out under a temperature condition of 0 to 100 ° C., preferably 60 to 70 ° C., for about 4 to 15 hours, preferably about 7 to 9 hours. Further, in the general formula (1), the dithiomaleimide derivative (1) in which R ¹ ≠ R ² is the rubeanic acid of the above formula (5) in which one amino group is protected, and R in the above formula (4). the reaction but by introducing R ¹ by reacting the compound represented by R ^1, then after removing the protecting group of the amino radical, R in the formula (4) is represented by R ² compound It can be synthesized by Reaction formula II

[0031]

[Chemical 10]

[In the formula, R is the same as defined above. ] This reaction is performed in the presence of zinc (II) chloride in the presence of maleic anhydride.
A mixture of (7) and amines (8) is reacted in the absence of solvent or in a suitable solvent to obtain a maleimide derivative represented by the formula (6), and then chlorine using thionyl chloride in the presence of pyridine. The above-mentioned formula, which is a raw material of reaction formula I
The compound of (4) is obtained.

The zinc (II) chloride is used in an amount of at least 1/20 times, preferably 1/10 times the molar amount of the compound (7). The reaction is usually performed at 40 to 150 ° C., preferably 100 to 120 ° C., and is completed in about 10 to 30 hours. Examples of the solvent include benzene, methylene chloride, chloroform, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide and the like.

Next, the electrophotographic photoreceptor of the present invention will be described in detail. As described above, in the electrophotographic photoreceptor of the present invention, the photosensitive layer provided on the conductive substrate is provided with the photosensitive layer containing the dithiomaleimide derivative (1) represented by the general formula (1). It is a thing. The electrophotographic photosensitive member of the present invention,
Either a single-layer type or a multi-layer type may be used, but the effect obtained by using the electron transfer agent is remarkably exhibited in the single-layer type photoreceptor.

The single-layer type electrophotographic photosensitive member comprises a conductive substrate and a single photosensitive layer provided on the conductive substrate.
At least a charge-generating agent and a hole-transporting agent, and a binder resin containing the dithiomaleimide imide derivative (1) as an electron-transporting agent. This single-layer type photoconductor is applicable to both positive charging and negative charging, but it is particularly preferable to use the positive charging type.

On the other hand, the multi-layer type electrophotographic photoconductor is one in which at least a charge generation layer and a charge transport layer are provided in this order on a conductive substrate, and a dithiomaleic acid imide derivative is used as an electron transport agent in the charge transport layer. It contains (1). The residual electric potential of this laminated electrophotographic photosensitive member is significantly lower than that of the conventional laminated electrophotographic photosensitive member.
The sensitivity is improved. Further, in order to transfer electrons from the charge generation layer to the charge transport layer more smoothly, it is preferable that the charge generation layer also contains the dithiomaleic acid imide derivative (1).

As described above, the dithiomaleic acid imide derivative (1) used in the electrophotographic photoreceptor of the present invention has good solubility in a solvent and compatibility with a binder resin, and a charge generating agent. Because it is excellent in matching with
The electrons are smoothly injected, and the electron transport property is excellent especially in a low electric field. Therefore, for example, in a positively charged single-layer type photoreceptor, the electrons released from the charge generation agent in the exposure step are smoothly injected into the electron transfer agent composed of the dithiomaleimide derivative represented by the general formula (1). It Then, by the transfer of electrons between the electron transfer agents, the electrons move to the surface of the photosensitive layer and cancel the positive charge (+) charged in advance on the surface of the photosensitive layer. On the other hand, the holes (+) are injected into the hole transfer material, move to the surface of the conductive substrate without being trapped, and the negative charge (-) on the surface of the conductive substrate is generated.
Cancel. In this way, it is considered that the sensitivity of the positively charged single-layer type photoreceptor is improved. The negatively charged single-layer type photoconductor only has the opposite direction of charge transfer from the above, and the sensitivity is similarly improved.

In the positively charged layered photoreceptor, the electrons released from the charge generating agent in the charge generating layer in the exposure step are the dithiomaleic imide represented by the general formula (1) in the charge transporting layer. It is smoothly injected into the electron transfer material composed of the derivative. Then, by the transfer of electrons between the electron transfer agent, the electrons move in the charge transport layer and reach the surface of the photosensitive layer,
The positive charge (+) previously charged on the surface of the photosensitive layer is canceled. On the other hand, holes (+) move directly from the charge generation layer to the surface of the conductive substrate, and cancel the negative charge (-) on the surface of the conductive substrate. In this way, it is considered that the sensitivity of the positively charged layered type photoreceptor is improved.

The charge generating agent that absorbs light upon exposure to the photosensitive member produces ion pairs [holes (+) and electrons (-)]. In order for the generated ion pairs to become free carriers and effectively cancel the surface charge, it is preferable that the ion pair recombine and disappear. The electrophotographic photoreceptor of the present invention is the above dithiomaleic acid imide derivative (1)
In addition, another electron transfer agent can be used in combination. In particular, an electron transfer material having an oxidation-reduction potential of -0.8 to -1.4 V is preferably used. The reason is as follows.

When an electron transfer agent having an oxidation-reduction potential of less than -1.4 V is used, LUMO (orbital having the lowest energy level among molecular orbitals having no electrons, and excited electrons are The energy level of () usually moves to this orbit.) Becomes higher than that of the charge generating agent, and the electrons do not move to the electron transferring agent during the generation of the ion pair, which does not lead to the improvement of the charge generating efficiency.

On the other hand, the redox potential is -1.4 V.
When a larger electron transfer material is used, the energy level of LUMO is lower than that of the charge generation material, so that when the ion pair is generated, the electron is transferred to the electron transfer material and the ion pair is easily separated into the carrier. Because. That is, the electron transfer agent acts on the charge generation and improves its generation efficiency.

On the other hand, in order to have high sensitivity, it is necessary that carrier traps due to impurities do not occur when the free carriers move. Usually, a trap due to a small amount of impurities exists in the moving process of the free carrier, and the free carrier moves while repeating trap-detrap, but an electron transfer agent having an oxidation-reduction potential larger than -0.8 V is used. In that case, the separated free carriers are dropped to a level that cannot be detrapped, and carrier traps occur, so that the movement is stopped.

On the other hand, the redox potential is -0.8 V.
When a smaller electron transfer material is used, carrier traps do not occur and free carriers move easily. As shown in FIG. 1, the above-mentioned redox potential was calculated using the following equation, by obtaining E ₁ and E ₂ shown in the figure from the relationship between the traction voltage (V) and the current (μA).

Oxidation-reduction potential (V) = (E ₁ + E ₂ ) / 2 The above-mentioned traction voltage (V) and current (μA) are three-electrode cyclic using the measurement solution prepared by mixing the following materials. It was measured by voltammetry. Electrode: Working electrode (glassy carbon electrode), counter electrode (platinum electrode) Reference electrode: Silver nitrate electrode (0.1 mol / liter AgNO ₃ -acetonitrile solution) Measurement solution Electrolyte: Tetra-n-butylammonium perchlorate 0.1 Molar substance to be measured: electron transfer agent 0.001 mol Solvent: CH ₂ Cl ₂ Prepare a measurement solution by mixing 1 liter or more of material.

The electron transfer agent is not particularly limited as long as it has a redox potential in the range of -0.8 to -1.4 V. For example, benzoquinone compound; naphthoquinone compound; anthraquinone compound. ;
Diphenoquinone compounds; malonnitrile compounds; thiopyran compounds; 2,4,8-trinitrothioxanthone; 3,4,5,7-tetranitro-9-fluorenone and other fluorenone compounds; dinitroanthracene;
Examples thereof include compounds such as dinitroacridine; nitroanthraquinone; dinitroanthraquinone.

However, considering the compatibility with the charge generating agent and the dithiomaleimide derivative (1) of the present invention, among the compounds exemplified above, the diphenoquinone compound represented by the general formula (2), or A compound which belongs to the benzoquinone compound represented by the general formula (3) and has an oxidation-reduction potential within the above range is most preferably used. Note that R ^A , R ^B , R ^C, and R ^D in the above formula are not limited thereto, but it is preferable that two or more of them are the same group.

Examples of the alkyl group, aralkyl group, alkoxy group and aryl group in the above formula include the same groups as described above. Examples of the cycloalkyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and other cycloalkyl groups having 3 to 6 carbon atoms.

The amino group which may have a substituent includes, for example, amino, monomethylamino,
Examples thereof include dimethylamino, monoethylamino, diethylamino and the like. Specific examples of such a diphenoquinone compound include, but are not limited to, for example, the formula (2-1)
3,5-dimethyl-3 ′, 5′-di (t-butyl) -4,4′-diphenoquinone represented by
0.86V) or 3, 5, 3 ', represented by the formula (2-2),
Examples thereof include 5'-tetrakis (t-butyl) -4,4'-diphenoquinone (oxidation-reduction potential -0.94V).

[0049]

[Chemical 11]

Specific examples of the benzoquinone compound include, but are not limited to, for example, p-benzoquinone represented by the formula (3-1) (oxidation-reduction potential -0.81 V) and the formula:
Examples thereof include 2,6-di (t-butyl) -p-benzoquinone represented by (3-2) (oxidation-reduction potential-1.31 V).

[0051]

[Chemical 12]

These electron-transporting agents can be used alone or in combination of two or more. In the present invention, in addition to the electron transfer agent, other conventionally known electron transfer agents may be contained in the photosensitive layer, and for example, compounds represented by the following general formulas (ET1) to (ET16), etc. can give.

[0053]

[Chemical 13]

[Wherein R ^e1 , R ^e2 , R ^e3 , R ^e4 and R ^e
e5 are the same or different, a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent,
It represents an aryl group which may have a substituent, an aralkyl group which may have a substituent, a phenoxy group which may have a substituent or a halogen atom. ]

[0055]

[Chemical 14]

[Wherein R ^e6 is an alkyl group, R ^e7 is an alkyl group which may have a substituent, an alkoxy group which may have a substituent, an aryl group which may have a substituent, a substituent The aralkyl group which may have a group, a halogen atom or a halogenated alkyl group is shown. γ represents an integer of 0 to 5. However, when γ is 2 or more, each R ^e7 may be different from each other. ]

[0057]

[Chemical 15]

[In the formula, R ^e8 and R ^e9 are the same or different and each represents an alkyl group. δ represents an integer of 1 to 4, and ε
Represents an integer of 0 to 4. However, when δ and ε is 2 or more, each R ^e8 and R ^e9 may be different. ]

[0059]

[Chemical 16]

[In the formula, R ^e10 represents an alkyl group, an aryl group, an aralkyl group, an alkoxy group, a halogenated alkyl group or a halogen atom. ζ is 0-4, η is 0-5
Indicates an integer. However, when η is 2 or more, each R ^e10 may be different. ]

[0061]

[Chemical 17]

[In the formula, R ^e11 represents an alkyl group, and σ represents an integer of 1 to 4. However, when σ is 2 or more, each R
^e11 may be different. ]

[0063]

[Chemical 18]

[In the formula, R ^e12 and R ^e13 are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group, an aralkyloxycarbonyl group, an alkoxy group, a hydroxyl group, a nitro group or a cyano group. X represents an oxygen atom, a = N-CN group, or a = C (CN) ₂ group. ]

[0065]

[Chemical 19]

[0066] wherein, R ^e14 is a hydrogen atom, a halogen atom, a phenyl group which may have an alkyl group or a substituted group, R ^e15 represents a halogen atom, an alkyl group which may have a substituent group, a substituted A phenyl group which may have a group, an alkoxycarbonyl group, an N-alkylcarbamoyl group, a cyano group or a nitro group is shown. lambda shows the integer of 0-3.
However, when λ is 2 or more, each ^Re15 may be different from each other. ]

[0067]

[Chemical 20]

[In the formula, θ represents an integer of 1 to 2. ]

[0069]

[Chemical 21]

[In the formula, R ^e16 and R ^e17 are the same or different and each represents a halogen atom, an alkyl group which may have a substituent, a cyano group, a nitro group or an alkoxycarbonyl group. ν and ξ are integers of 0 to 3. However, when ν or ξ is 2 or more, each R ^e16 and R ^e17 may be different from each other. ]

[0071]

[Chemical formula 22]

[ ^Wherein , R ^e18 and R ^e19 are the same or different and each represent a phenyl group, a polycyclic aromatic group or a heterocyclic group, and these groups may have a substituent. ]

[0073]

[Chemical formula 23]

[In the formula, R ^e20 represents an amino group, a dialkylamino group, an alkoxy group, an alkyl group or a phenyl group, and π represents an integer of 1 to 2. However, when π is 2,
Each R ^{e2 0} may be different from each other. ]

[0075]

[Chemical formula 24]

[In the formula, R ^e21 is a hydrogen atom, an alkyl group,
An aryl group, an alkoxy group or an aralkyl group is shown. ]

[0077]

[Chemical 25]

[ ^Wherein R ^e22 is a halogen atom, an alkyl group which may have a substituent, a phenyl group which may have a substituent, an alkoxycarbonyl group, an N-alkylcarbamoyl group, a cyano group or a nitro group. Indicates. μ represents an integer of 0 to 3. However, when μ is 2 or more, each R ^e22 may be different from each other. ]

[0079]

[Chemical formula 26]

[0080] [wherein, R ^e23 is a alkyl group or a substituted group may have a substituent indicates also aryl group, R ^e24 represents an alkyl group which may have a substituent, ^Represents an aryl group or a group —O—R ^e24a which may have R ^e24a in the above groups represents an alkyl group which may have a substituent or an aryl group which may have a substituent. ]

[0081]

[Chemical 27]

[Wherein R ^e25 , R ^e26 , R ^e27 ,
R ^e28 , R ^e29 , R ^e30 and R ^e31 are the same or different and each represents an alkyl group, an aryl group, an aralkyl group, an alkoxy group, a halogen atom or a halogenated alkyl group. χ and φ are the same or different and each represents an integer of 0 to 4. ]

[0083]

[Chemical 28]

[In the formula, R ^e32 and R ^e33 are the same or different and each represents an alkyl group, an aryl group, an alkoxy group, a halogen atom or a halogenated alkyl group. τ and ψ are the same or different and each represents an integer of 0 to 4. In the electron transfer agent exemplified above, examples of the alkyl group, aryl group, alkoxycarbonyl group, aralkyl group, alkoxy group, halogen atom and cycloalkyl group are:
The same groups as mentioned above can be mentioned.

Heterocyclic groups include, for example, thienyl,
Furyl, pyrrolyl, pyrrolidinyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, 2H-imidazolyl, pyrazolyl, triazolyl, tetrazolyl, pyranyl, pyridyl, piperidyl,
Examples include piperidino, 3-morpholinyl, morpholino, thiazolyl and the like. It may also be a heterocyclic group condensed with an aromatic ring.

Examples of the halogenated alkyl group include chloromethyl, bromomethyl, fluoromethyl, iodomethyl, 2-chloroethyl, 1-fluoroethyl and 3-
Chloropropyl, 2-bromopropyl, 1-chloropropyl, 2-chloro-1-methylethyl, 1-bromo-1
-Methylethyl, 4-iodobutyl, 3-fluorobutyl, 3-chloro-2-methylpropyl, 2-iodo-2
-Methylpropyl, 1-fluoro-2-methylpropyl, 2-chloro-1,1-dimethylethyl, 2-bromo-1,1-dimethylethyl, 5-bromopentyl, 4-
The part of the alkyl group such as chlorohexyl has 1 to 6 carbon atoms.
And halogenated alkyl groups.

Examples of the polycyclic aromatic group include naphthyl, phenanthryl, anthryl and the like. Examples of the aralkyloxycarbonyl group include those in which the aralkyl moiety is any of the various aralkyl groups described above. Examples of the N-alkylcarbamoyl group include those in which the alkyl portion is any of the various alkyl groups described above.

Examples of the dialkylamino group include those in which the alkyl portion is any of the various alkyl groups described above. In addition, even if two alkyls substituting for amino are the same,
They may be different from each other. Examples of the substituent which may be substituted on each of the above groups include a halogen atom, an amino group, a hydroxyl group, an optionally esterified carboxyl group, a cyano group, an alkyl group having 1 to 6 carbon atoms, and 1 to 6 carbon atoms. 2 to 2 carbon atoms which may have an alkoxy group or an aryl group
And the alkenyl group of 6 and the like. The substitution position of the substituent is not particularly limited.

Further, in the present invention, in addition to the above examples, conventionally known electron transporting substances, that is, benzoquinone compounds, malononitrile, thiopyran compounds, tetracyanoethylene, 2,4,8-trinitrothioxanthone,
Dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride and the like can be used.

The charge generating agent, hole transporting agent and binder resin used in the electrophotographic photosensitive member of the present invention are as follows. << Charge Generating Agent >> Examples of the charge generating agent include compounds represented by the following general formulas (CG1) to (CG12).

(CG1) Metal-free phthalocyanine

[0092]

[Chemical 29]

(CG2) Oxotitanyl phthalocyanine

[0094]

[Chemical 30]

(CG3) Perylene pigment

[0096]

[Chemical 31]

(In the formula, R ^g1 and R ^g2 are the same or different and each represents a substituted or unsubstituted alkyl group having 18 or less carbon atoms, a cycloalkyl group, an aryl group, an alkanoyl group or an aralkyl group.) (CG4 ) Bisazo pigment

[0098]

[Chemical 32]

[Wherein Cp ¹ and Cp ² are the same or different and each represents a coupler residue, and Q is represented by the following formula:

[0100]

[Chemical 33]

(In the formula, R ^g3 represents a hydrogen atom, an alkyl group, an aryl group or a heterocyclic group, and the alkyl group, the aryl group or the heterocyclic group may have a substituent ω.
Represents 0 or 1. )

[0102]

[Chemical 34]

[0103]

[Chemical 35]

(In the formula, R ^g4 and R ^g5 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group, an aryl group or an aralkyl group.)

[0105]

[Chemical 36]

[0106]

[Chemical 37]

[0107]

[Chemical 38]

(In the formula, R ^g6 represents a hydrogen atom, an ethyl group, a chloroethyl group or a hydroxyethyl group.)

[0109]

[Chemical Formula 39]

Or

[0111]

[Chemical 40]

( ^Wherein R ^g7 , R ^g8 and R ^g9 are the same or different and each represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group, an aryl group or an aralkyl group). Is shown as a group. ] (CG5) Dithioketopyrrolopyrrole pigment

[0113]

[Chemical 41]

(In the formula, R ^g10 and R ^g11 are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and R ^g12 and R ^g13 are the same or different and are a hydrogen atom, an alkyl group or an aryl group. (CG6) Metal-free naphthalocyanine pigment

[0115]

[Chemical 42]

( ^Wherein R ^g14 , R ^g15 , R ^g16 and R ^g14
g17 is the same or different and represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. ) (CG7) Metal naphthalocyanine pigment

[0117]

[Chemical 43]

(In the formula, R ^g18 , R ^g19 , R ^g20 and R ^g18
g21 is the same or different and represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and M represents Ti or V. ) (CG8) Squaline pigment

[0119]

[Chemical 44]

(In the formula, R ^g22 and R ^g23 are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom.) (CG9) Trisazo pigment

[0121]

[Chemical formula 45]

(In the formula, Cp ³ , Cp ⁴ and Cp ⁵ are the same or different and represent a coupler residue.) (CG10) Indigo pigment

[0123]

[Chemical formula 46]

(In the formula, R ^g24 and R ^g25 are the same or different and each represents a hydrogen atom, an alkyl group or an aryl group, and Z represents an oxygen atom or a sulfur atom.) (CG11) Azurenium pigment

[0125]

[Chemical 47]

(In the formula, R ^g26 and R ^g27 are the same or different and each represents a hydrogen atom, an alkyl group or an aryl group.) (CG12) Cyanine pigment

[0127]

[Chemical 48]

(In the formula, R ^g28 and R ^g29 are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and R ^g30 and R ^g31 are the same or different and are a hydrogen atom, an alkyl group or an aryl group. In the above-mentioned charge generating agent, the alkyl group is
In addition to the above-mentioned alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkyl group having 18 or less carbon atoms such as octyl, nonyl, decyl, dodecyl, tridecyl, pentadecyl, octadecyl and the like can be mentioned.

Examples of the cycloalkyl group, alkoxy group, alkanoyl group, heterocyclic group, aryl group and aralkyl group include the same groups as described above. Examples of the substituent which may be substituted on the above group include a halogen atom, an amino group, a hydroxyl group, a carboxyl group which may be esterified, a cyano group, an alkyl group having 1 to 6 carbon atoms, and 1 to 1 carbon atoms.
Examples thereof include a C6 alkoxy group and an alkenyl group having a carbon number of 2 to 6, which may have an aryl group.

Cp ¹ , Cp ² , Cp ³ , Cp ⁴ and C
Examples of the coupler residue represented by p ⁵ include groups represented by the following general formulas (Cp-1) to (Cp-11).

[0131]

[Chemical 49]

[0132]

[Chemical 50]

In each formula, R ^g32 represents a carbamoyl group, a sulfamoyl group, an allofanoyl group, an oxamoyl group, an anthraniloyl group, a carbazoyl group, a glycyl group, a hydantoyl group, a phthalamoyl group or a succinamoyl group. These groups, a halogen atom, a phenyl group which may have a substituent, a naphthyl group which may have a substituent, a nitro group, a cyano group, an alkyl group, an alkenyl group,
It may have a substituent such as a carbonyl group or a carboxyl group.

R ^g33 represents an atomic group necessary for being condensed with a benzene ring to form an aromatic ring, a polycyclic hydrocarbon or a heterocycle, and these rings have a substituent similar to the above. May be. R ^g34 represents an oxygen atom, a sulfur atom or an imino group. R ^g35 represents a divalent chain hydrocarbon group or an aromatic hydrocarbon group, and these groups may have the same substituents as described above.

R ^g36 represents an alkyl group, an aralkyl group, an aryl group or a heterocyclic group, and these groups may have the same substituents as described above. R ^g37 is necessary for forming a heterocycle with a divalent chain hydrocarbon group or an aromatic hydrocarbon group, or with the two nitrogen atoms in the above groups (Cp-1) to (Cp-11). It represents an atomic group, and these rings may have the same substituents as described above.

R ^g38 represents a hydrogen atom, an alkyl group, an amino group, a carbamoyl group, a sulfamoyl group, an allofanoyl group, a carboxyl group, an alkoxycarbonyl group, an aryl group or a cyano group, and the groups other than the hydrogen atom are the same as those described above. It may have a substituent. R ^g39 represents an alkyl group or an aryl group, and these groups may have the same substituents as described above.

Examples of the alkenyl group include vinyl,
The number of carbon atoms of allyl, 2-butenyl, 3-butenyl, 1-methylallyl, 2-pentenyl, 2-hexenyl, etc. is 2 to 2.
6 are alkenyl groups. In the above R ^g33 ,
Examples of the atomic group necessary for condensation with the benzene ring to form an aromatic ring include alkylene groups having 1 to 4 carbon atoms such as methylene, ethylene, trimethylene and tetramethylene.

Examples of the aromatic ring formed by condensation of the above R ^g33 and a benzene ring include naphthalene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring and naphthacene ring. In R ^g33 , the atomic group necessary for condensation with the benzene ring to form a polycyclic hydrocarbon is, for example, an alkylene group having 1 to 4 carbon atoms, or a carbazole ring, a benzocarbazole ring, a dibenzofuran ring. Etc.

^Further , in R ^g33 , the atomic group necessary for condensation with the benzene ring to form a heterocycle is, for example, benzofuranyl, benzothiophenyl, indolyl,
1H-indolyl, benzoxazolyl, benzothiazolyl, 1H-indazolyl, benzimidazolyl, chromenil, chromanyl, isochromanyl, quinolinyl, isoquinolinyl, cinnolinyl, phthalazinyl, quinazonilyl, quinoxalinyl, dibenzofuranyl, carbazolyl, xanthenyl, acridinyl, phenanthridinyl, Phenazinyl, phenoxazinyl, thianthrenyl and the like can be mentioned.

Examples of the aromatic heterocyclic group formed by the condensation of R ^g33 and the benzene ring include thienyl, furyl, pyrrolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, pyrazolyl, triazolyl, tetrazolyl, pyridyl, Thiazolyl is an example. It may also be a heterocyclic group condensed with another aromatic ring (for example, benzofuranyl, benzimidazolyl, benzoxazolyl, benzothiazolyl, quinolyl, etc.).

In R ^g35 and R ^g37 , ^examples of the divalent chain hydrocarbon group include ethylene, trimethylene and tetramethylene, and examples of the divalent aromatic hydrocarbon group include phenylene, naphthylene and phenanthrylene. Can be given. In R ^g36 , ^examples of the heterocyclic group include pyridyl, pyrazyl, thienyl, pyranyl, indolyl and the like.

In R ^g37 , ^examples of the atomic group necessary for forming a heterocycle with two nitrogen atoms include phenylene, naphthylene, phenanthrylene, ethylene, trimethylene, tetramethylene and the like.
Examples of the aromatic heterocyclic group formed by R ^g37 and two nitrogen atoms include, for example, benzimidazole,
Benzo [f] benzimidazole, dibenzo [e, g]
Examples thereof include benzimidazole and benzopyrimidine. These groups may have the same substituents as described above.

In R ^g38 , ^examples of the alkoxycarbonyl group include groups such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl and the like. In the present invention, in addition to the charge generating agents exemplified above, for example, selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, powder of an inorganic photoconductive material such as amorphous silicon, pyrylium salt, ansanthuron pigment, tritium. Conventionally known charge generating agents such as phenylmethane pigments, slene pigments, toluidine pigments, pyrazoline pigments and quinacridone pigments can be used.

The charge generating agents exemplified above may be used alone or in combination of two or more so as to have an absorption wavelength in a desired region. Among the charge generation agents exemplified above, a photoconductor having sensitivity in a wavelength region of 700 nm or more is required for a digital optical image forming apparatus such as a laser beam printer or a facsimile using a light source such as a semiconductor laser. Therefore, for example, a phthalocyanine-based pigment such as the metal-free phthalocyanine represented by the general formula (CG1) or the oxotitanyl phthalocyanine represented by the general formula (CG2) is preferably used. The crystal form of the phthalocyanine-based pigment is not particularly limited, and various types can be used.

On the other hand, an image forming apparatus of an analog optical system such as an electrostatic copying machine using a white light source such as a halogen lamp requires a photoreceptor having sensitivity in the visible region. The perylene pigment represented by (CG3) and the bisazo pigment represented by the general formula (CG4) are preferably used. <Hole transporting agent> As the hole transporting agent, various compounds having a high hole transporting ability, for example, the following general formulas (HT1) to (H
Examples thereof include compounds represented by T13).

[0146]

[Chemical 51]

[In the formula, R^h1, R^h2, R^h3, R^h4, R^h5Oh
And R^h6Are the same or different and have a halogen atom or a substituent.
Alkyl group which may have and alcohol which may have a substituent
An oxy group or an aryl group which may have a substituent is shown.
a and b are the same or different and each represents an integer of 0 to 4,
c, d, e and f are the same or different and are integers from 0 to 5
Indicates. However, a, b, c, d, e or f is 2 or more.
When each R^h1, R^h2, R ^h3, R^h4, R^h5And R^h6Is different
It may be. ]

[0148]

[Chemical 52]

[In the formula, R ^h7 , R ^h8 , R ^h9 , R ^h10 and R ^h11 are the same or different and each is a halogen atom, an alkyl group which may have a substituent or an alkoxy group which may have a substituent. Or, it represents an aryl group which may have a substituent.
g, h, i and j are the same or different and each represents an integer of 0 to 5, and k represents an integer of 0 to 4. However, g, h, i,
When j or k is 2 or more, each R ^h7 , R ^h8 , R ^h9 , R
^h10 and R ^h11 may be different. ]

[0150]

[Chemical 53]

[Wherein R ^h12 , R ^h13 , R ^h14 and R ^h12
h15 is the same or different and represents a halogen atom, an alkyl group which may have a substituent, an alkoxy group which may have a substituent or an aryl group which may have a substituent. R
^h16 represents a halogen atom, a cyano group, a nitro group, an alkyl group which may have a substituent, an alkoxy group which may have a substituent, or an aryl group which may have a substituent.
m, n, o and p are the same or different and each represents an integer of 0-5. q represents an integer of 1 to 6. However, m, n,
When o, p or q is 2 or more, each R ^h12 , R ^h13 , R
^h14, R ^h15 and R ^{h1 6} may be different. ]

[0152]

[Chemical 54]

[In the formula, R^h17, R^h18, R^h19And R
^h20Have the same or different halogen atoms and substituents
Optionally substituted alkyl group, optionally substituted alkoxy
A group or an aryl group which may have a substituent is shown. r,
s, t, and u are the same or different and are integers from 0 to 5
Show. However, when r, s, t or u is 2 or more, each R
^h17, R^h18, R^h19And R^h20Can be different
Yes. ]

[0154]

[Chemical 55]

[In the formula, R ^h21 and R ^h22 are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. R ^h23 , R ^h24 , R ^h25 and R
^h26 is the same or different and represents a hydrogen atom, an alkyl group or an aryl group. ]

[0156]

[Chemical 56]

[In the formula, R ^h27 , R ^h28 and R ^h29 are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. ]

[0158]

[Chemical 57]

[ ^Wherein R ^h30 , R ^h31 , R ^h32 and R ^h30
h33 is the same or different and is a hydrogen atom, a halogen atom,
An alkyl group or an alkoxy group is shown. ]

[0160]

[Chemical 58]

[In the formula, R ^h34 , R ^h35 , R ^h36 , and R ^h37
And R ^h38 are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. ]

[0162]

[Chemical 59]

[In the formula, R ^h39 represents a hydrogen atom or an alkyl group, and R ^h40 , R ^h41 and R ^{h4 2} are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. ]

[0164]

[Chemical 60]

[0165] wherein, R ^h43, R ^h44 and R ^h45 are the same or different and represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. ]

[0166]

[Chemical formula 61]

[ ^Wherein , R ^h46 and R ^h47 are the same or different and each represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent or an alkoxy group which may have a substituent. R ^h48 and R ^h49 are the same or different,
A hydrogen atom, an alkyl group which may have a substituent or an aryl group which may have a substituent is shown. ]

[0168]

[Chemical formula 62]

[In the formula, R^h50, R^h51, R^h52,
R^h53, R^h54And R^h55Are the same or different,
Alkyl group which may have a substituent, which may have a substituent
An alkoxy group or an aryl group which may have a substituent
Show. α represents an integer of 1 to 10, and v, w, x, y, z
And β are the same or different and each represents an integer of 0 to 2. However
, And when v, w, x, y, z or β is 2, each
R^h50, R^h51, R^h52, R^h53, R ^h54And R^h55
May be different. ]

[0170]

[Chemical formula 63]

[ ^Wherein R ^h56 , R ^h57 , R ^h58 and R ^h56
h59 is the same or different and is a hydrogen atom, a halogen atom,
Represents an alkyl group or an alkoxy group, and Φ is

[0172]

[Chemical 64]

The group (Φ-1), (Φ-2) or (Φ-3) represented by is shown. In the hole-transporting agent exemplified above, examples of the alkyl group, alkoxy group, halogen atom, aryl group and aralkyl group include the same groups as described above. Examples of the substituent that may be substituted on the above group include a halogen atom, an amino group, a hydroxyl group, an optionally esterified carboxyl group, a cyano group, an alkyl group having 1 to 6 carbon atoms, and a carbon number 1
Examples include an alkoxy group having 6 to 6 and an alkenyl group having 2 to 6 carbon atoms, which may have an aryl group. The substitution position of the substituent is not particularly limited.

In the present invention, in addition to the above examples, conventionally known hole transporting substances, that is, oxadiazoles such as 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole Compounds, styryl compounds such as 9- (4-diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, organic polysilane compounds, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline,
Nitrogen-containing cyclic compounds such as hydrazone compounds, triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, and triazole compounds, A condensed polycyclic compound or the like can be used.

In the present invention, the hole transport material may be used alone or in combination of two or more. Further, when using a hole transporting agent having film-forming properties such as polyvinylcarbazole, the binder resin is not always necessary. In the present invention, it is preferable to use one having an ionization potential (Ip) of 4.8 to 5.6 eV among the hole transporting agents, and 1 × 10 ⁻⁶ cm at an electric field strength of 3 × 10 ⁵ V / cm.
Those having a mobility of ² / V · sec or more are more preferable.

By using a hole transfer material having an ionization potential within the above range, the residual potential is further lowered,
The sensitivity is improved. The reason is not clear, but it is considered as follows. That is, the easiness of injecting charges from the charge generating agent into the hole transporting agent is closely related to the ionization potential of the hole transporting agent, and when the ionization potential of the hole transporting agent is larger than the above range. Is considered to cause a decrease in sensitivity due to a lower degree of charge injection from the charge generating agent to the hole transfer agent or a lower degree of hole transfer between the hole transfer agents. . On the other hand, in a system in which a hole transfer material and an electron transfer material coexist, it is necessary to pay attention to the interaction between them and more specifically to the formation of a charge transfer complex. When such a complex is formed between the two, recombination occurs between the holes and the electrons, and the mobility of the charge is lowered as a whole. When the ionization potential of the hole transfer material is smaller than the above range, the tendency to form a complex with the electron transfer material increases, and electron-hole recombination occurs, resulting in an apparent quantum yield. Is likely to decrease, resulting in a decrease in sensitivity.

When a bulky group is present in the electron transfer material, the formation of the charge transfer complex can be suppressed by its steric hindrance. Therefore, it is preferable to introduce a bulky substituent into the dithiomaleimide derivative (1) used as the electron transfer agent in the present invention.
Specific examples of the hole transfer agent that can be preferably used in the present invention include, for example, the formula (HT1-1) belonging to the benzidine derivative represented by the general formula (HT1):

[0178]

[Chemical 65]

Examples thereof include compounds represented by: <Binder Resin> As the binder resin for dispersing the above components, various resins conventionally used in the photosensitive layer can be used. For example, a styrene polymer and a styrene-butadiene copolymer Coal, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, Ionomer, vinyl chloride-vinyl acetate copolymer, polyester,
Alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin,
Thermoplastic resin such as polyether resin, polyester resin, silicone resin, epoxy resin, phenol resin,
Examples thereof include urea resins, melamine resins, other crosslinkable thermosetting resins, and photocurable resins such as epoxy acrylate and urethane-acrylate. These binder resins can be used alone or in combination of two or more. Suitable resins are styrene polymers, acrylic polymers, styrene-acrylic copolymers, polyesters, alkyd resins, polycarbonates, polyarylates and the like.

Next, a method for manufacturing the electrophotographic photosensitive member of the present invention will be described. In order to obtain a single-layer type electrophotographic photosensitive member, a predetermined electron transfer agent is dissolved or dispersed in a suitable solvent together with a charge generating agent, a hole transfer agent, a binder resin, etc. It may be applied on a conductive substrate and dried. In the case of a single-layer type photoreceptor, the binder resin 1
0.1 to 50 parts by weight of the charge generating agent with respect to 00 parts by weight,
The amount is preferably 0.5 to 30 parts by weight, and the electron transfer agent is 5 to 100 parts by weight, preferably 10 to 80 parts by weight. Further, the hole transport material is 5 to 500
It is blended in a proportion of parts by weight, preferably 25 to 200 parts by weight. Further, it is suitable that the total amount of the hole transfer agent and the electron transfer agent is 20 to 500 parts by weight, preferably 30 to 200 parts by weight, based on 100 parts by weight of the binder resin. When the single-layer type photosensitive layer contains an electron-accepting compound, the electron-accepting compound is added in an amount of 0.1 to 100 parts by weight of the binder resin.
It is suitable to add 40 parts by weight, preferably 0.5 to 20 parts by weight.

The thickness of the single-layer type photosensitive layer is 5 to 100.
μm, preferably 10 to 50 μm. In order to obtain a laminated type electrophotographic photoreceptor, first, a charge generation layer containing a charge generation agent is formed on a conductive substrate by means such as vapor deposition or coating, and then an electron transfer agent is formed on this charge generation layer. A coating liquid containing a binder resin and a binder resin may be applied by means such as coating and dried to form the charge transport layer.

In the multi-layer type photoreceptor, the charge generating agent and the binder resin constituting the charge generating layer can be used in various ratios, but the charge generating agent is added to 100 parts by weight of the binder resin. 5 to 1000 parts by weight, preferably 30 to 500
It is suitable to mix in a ratio of parts by weight. When the charge-generating layer contains an electron-accepting compound, the electron-accepting compound is added in an amount of 0.1-40 parts by weight, preferably 0.5-20 parts by weight, based on 100 parts by weight of the binder resin. Appropriate. When the charge generation layer contains an electron transfer agent, the electron transfer agent is added to the binder resin in an amount of 0.
It is suitable to add 5 to 50 parts by weight, preferably 1 to 40 parts by weight.

The electron-transporting agent and the binder resin constituting the charge-transporting layer can be used in various proportions within a range that does not hinder the transport of charge and a range that does not crystallize. In order to easily transport the generated charge, 10 to 10 parts by weight of the electron transfer agent may be added to 100 parts by weight of the binder resin.
It is suitable to mix it in an amount of 500 parts by weight, preferably 25 to 100 resin. When the charge transport layer contains an electron-accepting compound, the electron-accepting compound is added to the binder resin 10
0.1 to 40 parts by weight, preferably 0.
It is suitable to add 5 to 20 parts by weight.

The thickness of the laminated type photosensitive layer is about 0.01 to 5 μm, preferably 0.1 to 3 μm for the charge generation layer.
The charge transport layer has a thickness of 2 to 100 μm, preferably 5 to 50 μm. In the case of a single-layer type photoreceptor, between the conductive base and the photosensitive layer, and in the case of the multilayer type photoreceptor, between the conductive base and the charge generation layer, the conductive base and the charge transport layer. Between or between the charge generation layer and the charge transport layer,
A barrier layer may be formed in a range that does not impair the characteristics of the photoreceptor. Further, a protective layer may be formed on the surface of the photoconductor.

Each of the single-layer type and laminated type photosensitive layers contains various additives known per se, such as an antioxidant, a radical scavenger, a singlet quencher, within a range that does not adversely affect electrophotographic properties. A deterioration inhibitor such as an ultraviolet absorber, a softening agent, a plasticizer, a surface modifier, a bulking agent, a thickener, a dispersion stabilizer, a wax, an acceptor, a donor and the like can be added. Further, in order to improve the sensitivity of the photosensitive layer,
For example, known sensitizers such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generating agent.

Further, together with the dithiomaleimide derivative represented by the general formula (1), various electron transfer agents having a high electron transfer ability may be contained in the photosensitive layer. As the conductive substrate used in the photoreceptor of the present invention, various materials having conductivity can be used, for example, aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, Examples thereof include simple metals such as titanium, nickel, palladium, indium, stainless steel, and brass, plastic materials obtained by vapor deposition or laminating of the above metals, and glass coated with aluminum iodide, tin oxide, indium oxide, or the like.

The conductive substrate may be in the form of a sheet, a drum or the like, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. Further, it is preferable that the conductive substrate has sufficient mechanical strength when used. The photosensitive layer according to the present invention is manufactured by coating a coating solution prepared by dissolving or dispersing a resin composition containing each of the above components in a solvent on a conductive substrate and drying the coating solution.

That is, the above-mentioned charge generating agent, charge transporting agent, binder resin and the like are used together with a suitable solvent by a known method such as roll mill, ball mill, attritor, paint shaker or ultrasonic disperser. The coating liquid may be prepared by dispersing and mixing, and the coating liquid may be coated and dried by a known means. As the solvent for forming the coating liquid, various organic solvents can be used, for example, alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic hydrocarbons such as n-hexane, octane and cyclohexane, benzene, 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, cyclohexanone, etc. Examples thereof include ketones, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide, dimethylsulfoxide and the like. These solvents can be used alone or in combination of two or more.

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

[0190]

EXAMPLES The electrophotographic photosensitive member of the present invention will be described below with reference to synthesis examples and examples. Synthesis Example 1 [Synthesis of dithiomaleic acid imide derivative] Maleic anhydride represented by the above formula (7) (0.2 mmol, 20 g)
And 6-ethyl-o-toluidine (0.22 mmol, 30 g), which belongs to the above formula (8), in 100 ml of N,
After dissolving in N'-dimethylformamide (DMF),
Zinc chloride (0.02 mmol, 3 g) as a catalyst
Was added and the resulting mixture was heated to 110 ° C. and stirred overnight. After completion of the reaction, the mixture was treated with aqueous hydrochloric acid, and the precipitated solid was collected by filtration to obtain a compound N- (6-ethyl-o-toluidine) -maleimide in which R in the formula (6) was a 3-ethyltolyl group. (Yield 30%, 13 g).

Then, the compound represented by the above (6) was dissolved in 100 ml of thionyl chloride, and pyridine (0.
14 mmol, 11 g) was slowly added dropwise. The resulting solution was stirred for 20 minutes and then refluxed for 1 hour. After completion of the reaction, the solvent was distilled off under reduced pressure, the obtained residue was neutralized with hydrochloric acid water, and extracted with chloroform. The chloroform layer was dried over anhydrous sodium sulfate, the solvent was distilled off, and the obtained residue was reprecipitated with a mixed solution of chloroform-hexane, whereby R in the formula (4) was a 3-ethyltolyl group. The compound N- (6-ethyl-o-toluidine) -dichloromaleimide (yield 67%, 12 g) was obtained.

Further, the compound represented by the above (4) (0.
(02 mmol, 5.7 g) and rubeanic acid represented by the formula (5) were dissolved in 100 ml of dimethylformamide, triethylamine (0.05 mmol, 4 g) was added, and the mixture was heated to about 60 ° C. And stirred for 8 hours.
After the reaction was completed, the reaction solution was filtered, water was added to the obtained filtrate, and the mixture was extracted with ethyl acetate. After the ethyl acetate layer was dried over anhydrous sodium sulfate, the solvent was distilled off and recrystallized with a mixed solution of chloroform-hexane to give the compound of the present invention represented by the above formula (1-1) (yield 32%. ，
1.6 g) was obtained. Melting point 262 to 265 ° C. ¹ H-NMR spectrum of the product is shown in FIG. [Production of Electrophotographic Photoreceptor] The components used in the electrophotographic photoreceptor of the present invention are as follows. (i) Charge generator PcH ₂ : X-type metal-free phthalocyanine represented by the above formula (CG1) [ionization potential (Ip) = 5.38e
V] PcTiO: Oxotitanyl phthalocyanine represented by the above formula (CG2) (Ip = 5.32 eV) Perylene: The following formula (CG3-1) belonging to the above general formula (CG3):

[0193]

[Chemical formula 66]

The perylene pigment represented by (Ip = 5.50)
eV) (ii) Hole transport material HT1-1: Benzidine derivative represented by the formula (HT1-1) (Ip = 5.56 eV) (iii) Electron transport material 1-1: Obtained in Synthesis Example 1 Dithiomaleic acid imide derivative ET13-1: disclosed in JP-A-6-110227.
The following formula (ET13-1), which belongs to the naphthoquinone derivative represented by the formula (ET13):

[0195]

[Chemical formula 67]

3-phenyl-1,4-naphthoquinone 3-1 represented by: p-benzoquinone represented by the above formula (3-1) (oxidation-reduction potential = −0.81 V) 3-2: the above formula 2,6-di-t-butyl-p-benzoquinone represented by (3-2) (oxidation-reduction potential = -1.30 V) 2-1: 3,5-represented by the above formula (2-1) Dimethyl
3 ′, 5′-dit-butyl-4,4′-diphenoquinone (oxidation / reduction potential = −0.86 V) 2-2: 3,3 ′, 5,5 represented by the above formula (2-2) '-
Tetra-t-butyl-4,4′-diphenoquinone (oxidation-reduction potential = −0.94V) The ionization potential was measured using an atmospheric photoelectron analyzer (AC-1 manufactured by Riken Keiki Co., Ltd.). [Production of Single-Layer Electrophotographic Photoreceptor] Examples 1 to 3 and Comparative Examples 1 to 3 and 10 to 14 The charge generating agent, the hole transfer agent and the electron transfer agent shown in Table 1 were used together with the binder resin and the solvent. The components were blended in the ratios shown below and mixed and dispersed in a ball mill for 50 hours to prepare a single-layer type photosensitive layer coating liquid.

(Component) (Parts by Weight) Charge Generating Agent 5 Hole Transporting Agent 50 Electron Transporting Agent 30 Binder Resin (Polycarbonate) 100 Solvent (Tetrahydrofuran) 800 Next, the above coating liquid is applied to aluminum as a conductive base material. A single layer type electrophotographic photosensitive member having a film thickness of 15 to 20 μm was prepared by coating the surface of the blank tube by a dip coating method and drying with hot air at 100 ° C. for 60 minutes. Examples 4 to 7 and Comparative Examples 4 to 7 5 parts by weight of charge generating agent, 50 parts by weight of hole transferring material, 30 parts by weight of electron transferring material, 100 parts by weight of binder resin and 800 solvent.
In addition to the parts by weight, the above formula (2
-1) to (2-2), (3-1) to (3-2) represented by electron transfer agent 1
A single-layer type electrophotographic photosensitive member was produced in the same manner as in Examples 1 to 3 except that 0 part by weight was blended to prepare a single-layer type photosensitive layer coating liquid. [Preparation of Laminated Electrophotographic Photoreceptor] Examples 8 and 9 and Comparative Examples 8, 9, 15 and 16 100 parts by weight of the charge generating agent shown in Table 1, 100 parts by weight of a binder resin (polyvinyl butyral) and a solvent (tetrahydrofuran). ) 2000 parts by weight were mixed and dispersed by a ball mill for 50 hours to prepare a coating solution for the charge generation layer. This coating solution was applied to the surface of an aluminum base tube, which is a conductive base material, by a dip coating method, and dried with hot air at 100 ° C. for 60 minutes to form a charge generation layer having a film thickness of 1 μm.

Next, 100 parts by weight of the electron transfer agent shown in Table 1, 100 parts by weight of the binder resin (polycarbonate) and 800 parts by weight of the solvent (toluene) were mixed and dispersed in a ball mill for 50 hours to obtain a coating solution for the charge transfer layer. Prepared. Then, this coating solution is applied onto the charge generation layer by a dip coating method, and dried with hot air at 100 ° C. for 60 minutes to obtain a film thickness of 2
A charge transport layer having a thickness of 0 μm was formed to prepare a laminated electrophotographic photosensitive member. (Evaluation of Photoreceptor Characteristics) The electrophotographic photoreceptors obtained in the above Examples and Comparative Examples were subjected to the following photosensitivity test to evaluate their sensitivity characteristics. Photosensitivity test Using a drum-type sensitivity tester manufactured by GENTEC, a voltage was applied to the photoconductors of the above Examples and Comparative Examples to charge them to + 700V. Next, this photosensitive member was irradiated with light to be exposed, and the potential on the surface of the photosensitive member 330 milliseconds after the exposure was measured as the post-exposure potential V _L (V).

The conditions of light irradiation are as follows:
The charge generating agent differs depending on whether it is a phthalocyanine type or a perylene type. (1) Phthalocyanine-based pigment: Light monochromaticized to 780 nm (half-value width 20 nm) using a bandpass filter on the surface of the photoreceptor charged to +700 V (halogen lamp, light intensity: 16 μW / cm ² ).
Irradiate for 80 milliseconds. (2) In the case of perylene pigment, the surface of the photoreceptor charged to +700 V was irradiated with white light of a halogen lamp (light intensity: 147 μW / cm ² ) for 50 milliseconds.

Table 1 shows the measurement results of the components used in the above Examples and Comparative Examples and the post-exposure potential V _L.

[0201]

[Table 1]

As is clear from Table 1, the photoconductors of Examples 1 to 9 were compared with the photoconductors of Comparative Examples in which a diphenoquinone derivative or a naphthoquinone derivative was used as an electron transfer agent, or no electron transfer agent was used. As a result, the post-exposure potential is lowered, and it can be seen that it has high sensitivity. Also,
The photoconductors of Examples 4 to 7 are the electron transfer agent having a predetermined redox potential and the dithiomaleimide derivative of the present invention.
Since (1) is contained, the post-exposure potential is lower than that of the photoreceptors of the other examples, and it is understood that the photoreceptor has higher sensitivity.

[0203]

The dithiomaleic acid imide derivative (1) used in the electrophotosensitive material of the present invention has a high electron transporting ability. Therefore, such a dithiomaleimide derivative (1)
The electrophotographic photosensitive member of the present invention containing as an electron transfer agent has a significantly reduced residual potential and high sensitivity. Further, by adding an electron transfer agent having a specific redox potential, the residual potential is further lowered, and a photoreceptor having improved sensitivity can be obtained.

By using the photoconductor of the present invention, it is possible to increase the speed of copying machines, printers and the like.

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between a traction voltage (V) and a current (A) for obtaining a redox potential in the present invention.

FIG. 2 is a dithiomaleimide derivative (1-1) of the present invention.
2 is a graph showing the ¹ H-NMR spectrum of

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A 1-206349 (JP, A) JP-A 5-142812 (JP, A) Chemical Absrtacts, Vol. 111 (1989) P. 105, Abstract No. J. Heterocycl. Chem. , Vol. 28, No. 5 (1991) P. 1445-1447 J. Heterocycl. Chem. , Vol. 29, No. 2 (1992) P. 439-443 (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 5/00 CA (STN) REGISTRY (STN)

Claims (4)

(57) [Claims] 1. A compound of the general formula (1): embedded image on a conductive substrate. [In the formula, R ¹ and R ² are the same or different and each represents an aryl group which may have a substituent. ] An electrophotographic photoreceptor provided with a photosensitive layer containing a dithiomaleimide derivative represented by the following. 2. The photosensitive layer contains a hole transfer material in the same layer.
The electrophotographic photosensitive member according to claim 1, which is a single-layer type photosensitive layer having the same . 3. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer contains an electron transfer agent having an oxidation-reduction potential of −0.8 to −1.4V. 4. The electron transfer agent is represented by the general formula (2): [In the formula, R ^A , R ^B , R ^C and R ^D are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a cycloalkyl group or an amino group. ] Or a diphenoquinone derivative represented by the general formula (3): [In the formula, R ^E , R ^F , R ^G and R ^H are the same or different and each is a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a cycloalkyl group or an amino group which may have a substituent. Indicates a group. ] The electrophotographic photosensitive member according to claim 3, which is a benzoquinone derivative represented by the following formula.