JP2001305766A - Electrophotographic photoreceptor, process cartridge and electrophotographic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor which shows high latitude for selection of physical properties, which can be easily manufactured with high yield of a charge transfer material in the manufacture process and which can form an image of high picture quality. SOLUTION: The electrophotographic photoreceptor has at least one photosensitive layer containing a charge transfer material on the surface of a conductive supporting body, and the charge transfer material is prepared by block copolymerization and/or graft copolymerization of a charge transfer compound having a repeating unit expressed by formula (1) and an insulating compound. In formula, Ar1 and Ar2 represent aryl groups, X1 and X2 represent arylene groups, X3 is a bivalent hydrocarbon group or hetero atom-containing hydrocarbon group having an aromatic ring structure, L is a bivalent hydrocarbon group or hetero atom-containing hydrocarbon group and L may contain a branched structure or cyclic structure, and m is 0 or 1. One or more aryl groups expressed by Ar1, Ar2 have a reactive group as a substituent in the charge transfer compound as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member using a novel charge transporting copolymer, a process cartridge using the same, and an electrophotographic apparatus, and particularly suitable for a digital electrophotographic method. The present invention relates to an electrophotographic photosensitive member, a process cartridge, and a digital electrophotographic apparatus.

[0002]

2. Description of the Related Art Electrophotographic technology has recently played a central role in the fields of copiers, printers, facsimile machines and the like because of its advantages such as high speed and high printing quality. 2. Description of the Related Art As an electrophotographic photoreceptor used in the electrophotographic technology, a photoconductor using an inorganic photoconductive material such as selenium, a selenium-tellurium alloy, or a selenium-arsenic alloy has been widely known. On the other hand, electrophotographic photoreceptors using organic photoconductive materials, which have superior advantages in cost, manufacturability, disposability, etc., compared to these inorganic photoreceptors, have been actively researched. It has surpassed that of photoreceptors. In particular, with the development of a function-separated type lamination structure in which photocharge generation and charge transport, which are the elementary processes of photoconduction, are carried out in separate layers, the degree of freedom in material selection is increased, and significant performance improvements are achieved. Finally, at present, this function-separated and laminated organic photoreceptor has become the mainstream of electrophotographic photoreceptors.

[0003] That is, materials excellent in both charge generation ability and charge transport ability are rare, and it was difficult to design and develop such a material. By adopting a function-separated lamination structure using a combination of materials excellent in each function, a high-performance electrophotographic photosensitive member can be obtained. As the charge generation layer for the function-separated laminated organic photoreceptor, a pigment excellent in charge generation ability, such as a quinone pigment, a perylene pigment, an azo pigment, a phthalocyanine pigment, or selenium, was directly formed by vapor deposition or the like. And those dispersed in a binder resin at a high concentration have been put to practical use. On the other hand, as the charge transport layer, a material in which a low-molecular compound having excellent charge transport ability such as a hydrazone compound, a benzidine compound, an amine compound, and a stilbene compound is molecularly dispersed in an insulating resin is used.

A conventional photoconductor used for an analog type electrophotographic copying machine that optically forms an image of a document on a photoconductor and exposes the same to improve the reproducibility of halftones based on density gradation. Therefore, a photoconductor having a photo-induced potential decay characteristic as shown in FIG. 1, that is, a photoconductor which causes a potential decay in proportion to the exposure amount (hereinafter, referred to as a “J-shaped photoconductor”). Is required. The above inorganic photoreceptor,
All of the function-separated stacked organic photoreceptors exhibit photoinduced potential decay characteristics falling within this category.

However, in a digital electrophotographic apparatus, which has been actively researched and developed in response to recent demands for higher image quality, higher added value, networking, etc., gray scale is generally represented by an area ratio of dots or the like. As shown in FIG. 2, the potential is not attenuated until a certain exposure amount is reached, and a sharp potential decay occurs when the exposure amount is exceeded. It is desirable to use a photoreceptor having a potential decay characteristic (hereinafter, referred to as an “S-shaped photoreceptor”) from the viewpoint of increasing the sharpness of pixels.

This S-shaped photoinduced potential decay characteristic is based on ZnO
Is a known phenomenon in a single-layer type photoreceptor in which an inorganic pigment such as phthalocyanine or an organic pigment such as phthalocyanine is dispersed in a resin (for example, RM Schaffert: "Ele").
crophotography ", Focal Pr
ess, p. 344 (1975); W. Weig
1, J .; Mammino, G .; L. Whitake
r, R. W. Radler, J .; F. Byrne: "C
current Problems in Electr
ophotography ", Walter de G
ruyter, p. 287 (1972)). In particular, there have been proposed a large number of single-layer photoreceptors for laser exposure in which a phthalocyanine pigment having photosensitivity in the near-infrared region, which is a wavelength of a semiconductor laser that is widely used at present, is dispersed in a resin (for example, Nguyen Chang). K, Aizawa: Journal of the Chemical Society of Japan, p.393 (1986), JP-A-1-169454.
JP-A-2-207258 and JP-A-3-31847
And JP-A-5-313387.

However, in these single-layer type photoreceptors, it is necessary that a single material fulfills both functions of charge generation and charge transport, but as described above, materials having excellent performance in both functions are rare. However, a material that can be put to practical use has not yet been obtained. In particular, since pigment particles generally have many trap levels, they have disadvantages such as low charge transport ability, residual charge, and low repetition stability, and are unsuitable for carrying charge transport. In order to fundamentally solve this problem, increase the degree of freedom in material selection, and thus improve overall photoconductor characteristics, even in the case of an S-shaped photoconductor,
The introduction of a function-separated configuration is essential.

To solve this problem, D.S. M. Pai et al., In a laminated photoreceptor comprising a charge generation layer and a charge transport layer, including at least two charge transport regions and one electrically inactive region as a charge transport layer, and contacting each other as the charge transport region. It is reported that an S-shaped photo-induced potential decay characteristic can be realized in combination with an arbitrary charge generation layer by using a non-uniform charge transport layer having a convoluted charge transport path. -83077 (U.S. Pat. No. 5,306,586).

Further, the present inventors have invented that a photoconductor having a three-layer structure comprising a charge generation layer, a non-uniform charge transport layer, and a uniform charge transport layer exhibits an S-shaped photoinduced potential decay characteristic. (Japanese Patent Application No. 7-208552). M. Pa
The inventors have succeeded in further increasing the degree of function separation from the inventions such as i.

However, in these inventions, the function of making the photo-induced potential attenuation characteristic, which is a key, an S-shape (hereinafter, referred to as the function).
Specific examples of the heterogeneous charge transporting layer responsible for “S-shaping” include a resin dispersion film of a phthalocyanine pigment, a resin dispersion film of hexagonal selenium, and a polyvinyl carbazole-dodecyl methacrylate phase-separated block copolymer. However, these materials have the following problems, and a new development of a material for a non-uniform charge transport layer was indispensable for putting the above-mentioned invention into practical use.

That is, when a color pigment having a charge generating ability such as a phthalocyanine pigment or hexagonal selenium is used as a charge transporting material for a heterogeneous charge transporting layer, the charge generating layer is exposed from the charge transporting layer side. In this case, light absorption in the non-uniform charge transport layer and the resulting charge generation have adverse effects on photosensitivity and chargeability, and have caused problems such as a decrease in repetition stability.

This problem can be avoided by using a charge generation layer having photosensitivity in a wavelength range where the non-uniform charge transport layer does not absorb light and using an exposure apparatus that performs exposure only within the wavelength range. However, restrictions on materials and equipment are lent, and fundamental improvement measures are desired. Furthermore, in the production of a resin dispersion film of a phthalocyanine pigment or a resin dispersion film of hexagonal selenium, a pulverization and / or dispersion step of these pigments is necessary. However, the pulverization requires enormous energy, and impurities are mixed. It is dangerous. Furthermore, it is generally difficult to obtain a stable dispersion, which requires a great deal of effort in searching for a dispersing solvent and a binder resin, and significantly restricts the selected materials. In addition, modification of the dispersion by crystal growth or agglomeration in the dispersion is generally unavoidable, and cannot be used for a long period of time, resulting in an increase in cost.

On the other hand, a polyvinyl carbazole-dodecyl methacrylate phase-separated block copolymer is a special block copolymer.
It is synthesized using a functional initiator and has problems such as difficulty in production and high cost. Further, there are problems such as low mechanical strength, low charge mobility, and low charge injection property. However, since the phase-separated block copolymer is a uniform solution as a coating solution and separates into phases to give a desired heterogeneous charge transport layer upon drying, the above-mentioned problems relating to pulverization / dispersion are not solved. Has the advantage that it is fundamentally eliminated. In addition, since it is not a pigment, the above-mentioned problem relating to light exposure does not occur.

As a charge-transporting polymer, it has long been known that polyvinyl carbazole is effective as a charge-transporting material for an electrophotographic photosensitive member, but it has low mechanical strength and low charge mobility. And practically essential problems such as low charge injection property. In order to solve this problem, the charge transporting layer, which is a function required for the charge transporting layer, is separated from mechanical properties such as film formability, flexibility, and strength.
Materials have been developed based on the concept of function separation in which each is assigned to a separate material. As described above, at present, triarylamine-based charge transporting low-molecular compounds having high charge transportability, A molecular dispersion composite material made of a polycarbonate resin having excellent flexibility and strength has become the mainstream of the charge transport layer material for electrophotography.

However, such a molecularly dispersed composite material has a problem in that the molecularly dispersed charge transporting low molecular weight compound is crystallized with the passage of time and / or heating, and the characteristics are deteriorated. There was a limit on the use of the device or its application to devices that generate heat. In addition, when used in an electrophotographic photoreceptor for a liquid developing type electrophotographic apparatus capable of obtaining high image quality, the charge transporting low molecular compound dissolves or crystallizes when exposed to the developer, and the charge transport layer Had problems such as denaturation or cracking. Furthermore, in order to ensure sufficient charge transporting properties, it is necessary to disperse the charge transporting low molecular weight compound in the resin at a high concentration of 35 to 60% by weight, which results in poor mechanical properties such as flexibility and strength. Even if an excellent resin is used, the mechanical properties of the composite film are limited.

In order for organic charge transport materials to be widely used in organic electronic devices, including electrophotographic photosensitive members that are required to have a longer life, higher durability, and lower cost, the above-mentioned problems must be solved. Overcoming is indispensable, and as a means of this, research and development of high-performance charge-transporting polymers instead of polyvinylcarbazole have recently been activated again. To date, many charge-transporting polymers containing a triarylamine skeleton in the main chain or side chain have been developed based on the knowledge that triarylamine-based charge-transporting low-molecular compounds have high charge-transport properties. (See, for example, US Pat.
6,443, 4,806,444,
4,801,517 and 4,937,165
No. 4,959,288, JP-A-61-1986.
JP-A-20953, JP-A-1-134456,
JP-A-1-134457, JP-A-1-134462, JP-A-4-1330065, JP-A-4-133066, JP-A-8-176293, JP-A-8-176293
No.).

However, these charge-transporting polymers are homopolymers or random copolymers obtained by mixing and copolymerizing several kinds of monomers, and exhibit essentially no phase separation properties. In this case, a non-uniform charge transport layer for forming an S-shape cannot be formed. For this issue,
The present inventors have found that a phase-separable polymer blend obtained by adding an insulating polymer incompatible with the charge-transporting polymer to the charge-transporting polymer is effective as a non-uniform charge-transporting layer for forming an S-shape. (Japanese Unexamined Patent Application Publication No. 10-6910)
9 etc.).

However, in the polymer blend, there is a problem that the phase separation scale is generally several μm or more and the homogeneity of the image may be reduced. Further, there is also a problem in manufacturing reproducibility that the phase separation scale greatly changes depending on the film forming conditions such as the drying speed and the drying temperature, and the electrophotographic characteristics greatly change accordingly.

In order to solve the above problem, the present inventors have considered that a non-uniform charge transport layer is constituted by a charge transport block copolymer or a charge transport graft copolymer having a small phase separation scale, and An S-shaped electrophotographic photosensitive member having high mechanical strength, appropriate non-uniform charge characteristics, and high durability has been proposed.

However, with the advance of technology, there is a demand for an electrophotographic photoreceptor which can obtain a charge transporting material having a high degree of freedom in selecting physical properties and the like with a high yield and can be easily manufactured.

[0021]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances in the prior art, and overcomes the above-mentioned problems and the like and responds to the above-mentioned various demands. The task is to achieve the purpose. That is, the present invention uses an electrophotographic photoreceptor which has a high degree of freedom in selection of physical properties and the like, is easy to manufacture, has a high yield of a charge transport material at the time of manufacture, and can form a high quality image. It is an object to provide a process cartridge and an electrophotographic apparatus.

[0022]

Means for Solving the Problems As a result of intensive studies on the charge transporting material and the polymer material, the present inventors have found that a block copolymer in which a plurality of blocks having desired functions are connected by a covalent bond. Alternatively, a multifunctional material can be obtained easily and in high yield without impairing each function by a graft copolymerization technique, and is composed of a charge transporting block containing a triarylamine structure and an insulating block. The copolymer has excellent overall properties as a charge transporting material, and particularly when both blocks are incompatible, it is suitable as a material for a heterogeneous charge transporting layer for an S-shaped photoreceptor. And completed the present invention.

The means for solving the above problems are as follows. That is, <1> an electrophotographic photosensitive member in which at least one photosensitive layer containing a charge transport material is formed on a conductive support surface, wherein the charge transport material is represented by the following general formula (1). An electrophotographic photosensitive member obtained by subjecting a charge transporting compound having a repeating unit to an insulating compound to block copolymerization and / or graft copolymerization. General formula (1)

[0024]

Embedded image

In the general formula (1), Ar ¹ and Ar ² represent an aryl group. Further, as a whole charge transporting compound having a repeating unit represented by the general formula (1), at least one of the aryl groups represented by Ar ¹ or Ar ² has a reactive group as a substituent. . X ¹ and X ² are
Each independently represents an arylene group, and the arylene group may be substituted. X ³ represents a divalent hydrocarbon group having an aromatic ring structure or a hetero atom-containing hydrocarbon group. L represents a divalent hydrocarbon group or a heteroatom-containing hydrocarbon group. L may include a branched structure or a ring structure. m represents 0 or 1. In the charge transporting material, the site derived from the charge transporting compound corresponds to a charge transporting block, and the site derived from the insulating compound is
It corresponds to an insulating block. Hereinafter, in the charge transporting material, a portion derived from the charge transporting compound may be referred to as a “charge transporting block”, and a portion derived from the insulating compound may be referred to as an “insulating block”. <2> The electrophotographic photosensitive member according to <1>, wherein the reactive group is a hydroxymethyl group. In the electrophotographic photoreceptor, it is preferable that a reactive group such as a hydroxymethyl group be a curing site and the charge transporting block be cured. It is preferable that the charge transport block and the insulating block are incompatible with each other. The insulating block is preferably formed by polymerizing a vinyl monomer. The vinyl monomer is at least one of the compounds represented by the following general formula (2).
Preferably, it contains a species.

General formula (2)

Embedded image

In the general formula (2), R ^{1 to} R ³ each independently represent a hydrogen atom, a halogen atom, an alkyl group or an aryl group. When any of R ^{1 to} R ³ is an alkyl group or an aryl group, the alkyl group or the aryl group is
It may be substituted. R ⁴ represents a halogen atom, an alkyl group, an aryl group, an alkoxyl group, an acyl group, an acyloxy group, or an alkoxylcarbonyl group. R
^{When 4} is an alkyl group, an aryl group, an alkoxyl group, an acyl group, an acyloxy group, or an alkoxyl carbonyl group, R ⁴ may be substituted.

In the electrophotographic photoreceptor, the photosensitive layer containing the charge transporting material is a charge transporting layer, and at least one charge generating layer is formed thereon to form a laminated photosensitive layer as a whole. Is preferred. The charge transport layer comprises two or more layers, and at least one of the charge transport layers
Preferably, the layer comprises the charge transport material. Preferably, the charge transport layer comprises at least a heterogeneous charge transport layer and a uniform charge transport layer, and the layer containing the charge transport material is a heterogeneous charge transport layer. Further, in the electrophotographic photosensitive member, the exposure amount required for 50% potential decay is 1
It is preferably less than 5 times the exposure amount required for 0% potential decay, and more preferably less than 3 times.

<3> At least one member selected from the group consisting of the electrophotographic photosensitive member according to <1> or <2>, and a charging unit, a developing unit, a discharging unit, and a cleaning unit.
And a process cartridge detachable from the electrophotographic apparatus. <4> An electrophotographic apparatus including the electrophotographic photosensitive member according to <1> or <2>, or the process cartridge according to <3>.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. [Electrophotographic Photoreceptor] The electrophotographic photoreceptor of the present invention comprises at least one photosensitive layer formed on the surface of a conductive support, and other layers if necessary.

-Photosensitive Layer- The photosensitive layer contains a charge transporting material and, if necessary, other components. The charge transport material is obtained by block copolymerization and / or graft copolymerization of a charge transport compound having a repeating unit represented by the following general formula (1) and an insulating compound. General formula (1)

[0032]

Embedded image

In the general formula (1), Ar ¹ and Ar ² represent an aryl group. Further, as a whole charge transporting compound having a repeating unit represented by the general formula (1), at least one of the aryl groups represented by Ar ¹ or Ar ² has a reactive group as a substituent. . X ¹ and X ² are
Each independently represents an arylene group, and the arylene group may be substituted. X ³ represents a divalent hydrocarbon group having an aromatic ring structure or a hetero atom-containing hydrocarbon group. L represents a divalent hydrocarbon group or a heteroatom-containing hydrocarbon group. L may include a branched structure or a ring structure. m represents 0 or 1, respectively.

In the charge transporting material, the charge transporting block has the general formula (1) in terms of charge mobility, charge injection property, charge lifetime, visible light and infrared light transmittance, and chemical stability. ) Must be a block having a repeating unit represented by In particular, as the whole charge transporting compound having the repeating unit represented by the general formula (1), A
Since at least ^{one of the} aryl groups represented by r ¹ or Ar ² has a reactive group as a substituent, the charge transporting material has an insulating block having various characteristics together with a high charge transporting ability. Mechanical strength, glass transition temperature, crystallinity, refractive index,
Various physical properties such as adhesiveness, adsorptivity, flexibility, solubility, melting property, and phase separation state can be provided. Further, by adjusting the number of the reactive groups, the introduction position, and the like, these physical properties can be easily controlled (that is, the degree of freedom in selecting the physical properties and the like becomes high). Furthermore, the reactive group increases the reaction rate at the time of copolymerizing the charge transporting compound having the repeating unit represented by the general formula (1) and the insulating compound, and thus the yield is high in the yield. A charge transport material is obtained, and as a result, the production of the electrophotographic photoreceptor of the present invention using the charge transport material is facilitated.

In the charge transport block,
Ar in the repeating unit represented by the above general formula (1)
¹, Ar^TwoHas a reactive group as a substituent at all times.
It is not necessary to use
Does not have a reactive group, or A in the repeating unit
r¹Or Ar^TwoOne has a reactive group, A
r ¹, Ar^TwoBoth may have a reactive group.
No. Further, in the charge transporting block,
Having a repeating unit containing a triarylamine structure of
And the formula weight of the charge transporting block is preferably 2
000 or more is preferable.

In the general formula (1), Ar ¹ and A
Specific examples of the aryl group represented by r ² include a phenyl group, a biphenyl group, a naphthyl group, and a pyrenyl group. These may be substituted with a methyl group, an ethyl group, a methoxy group, a halogen atom, or the like. Examples of the reactive group include a hydroxymethyl group, a formyl group, and a carboxyl group, and among them, a hydroxymethyl group is preferable. Specific examples of the aryl group having a hydroxymethyl group as a reactive group include the following, but are not limited thereto.

[0037]

Embedded image

In the general formula (1), X ¹ and X ² each independently represent an arylene group, and the arylene group is
It may be substituted. Specific examples of the arylene group include a phenylene group, a biphenylene group, a terphenylene group, and a naphthylene group.When these are substituted, the substituents include a methyl group, an ethyl group,
Examples include a methoxy group and a halogen group.

In the general formula (1), X ³ represents a divalent hydrocarbon group having an aromatic ring structure or a hetero atom-containing hydrocarbon group. Specific examples thereof include a phenylene group, a biphenylene group, a terphenylene group, a naphthylene group, a methylenediphenyl group, a cyclohexyredenediphenyl group,
Oxydiphenyl group, thiodiphenyl group and the like can be mentioned. These may be substituted, examples of the substituent include a methyl group, an ethyl group, a methoxy group, and a halogen atom, among which, particularly, a substituted or unsubstituted biphenylene group or a terphenylene group, It is particularly preferable in terms of charge transportability.

In the general formula (1), L represents a divalent hydrocarbon group or a heteroatom-containing hydrocarbon group, and may have a branched structure or a ring structure. The L, from the viewpoint of mechanical strength, an ether bond, an ester bond, carbonate bond, a hetero atom-containing hydrocarbon group of C ₁ -C ₂₀ having a coupling group selected from siloxane bonds and the like are preferable. Specific examples include the following.

[0041] _{-O-CO-C 2 H 4} -CO-O -, - O-CO-C 6 H 4 -CO-O-, -CH 2 -O-CH 2 -, - O-CO-O- _{, -C 3 H 6 Si (CH} 3) 2 -O-Si (CH 3) 2 -C 3 H 6 -, -CO-O-C 2 H 4 -O-CO-, -C 2 H 4 -CO —O—C ₂ H ₄ —O—CO—C ₂ H ₄ —, —O—CO—OC ₆ H ₄ —C (CH ₃ ) ₂ —C ₆ H ₄ —O—CO—O—,

Specific examples of the repeating unit represented by the general formula (1) are shown in Tables 1 to 15 by partial structural formulas (partial structural formulas 1 to 75), but are not limited thereto.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

[Table 4]

[0047]

[Table 5]

[0048]

[Table 6]

[0049]

[Table 7]

[0050]

[Table 8]

[0051]

[Table 9]

[0052]

[Table 10]

[0053]

[Table 11]

[0054]

[Table 12]

[0055]

[Table 13]

[0056]

[Table 14]

[0057]

[Table 15]

Among them, the partial structural formulas 2, 7, 12, 22, 27, 32, and 3 have high mobility and high molecular weight.
The repeating units represented by 7, 42, 47, and 52 are preferred.

In the charge transporting material, the insulating block is preferably made of the following general formula (2) from the viewpoint of mechanical strength, flexibility, transparency of visible light and infrared light, and chemical stability.
Those obtained by polymerizing at least one kind of vinyl monomer represented by the formula (1) are preferable.

Formula (2)

Embedded image

In the general formula (2), R ^{1 to} R ³ each independently represent a hydrogen atom, a halogen atom, an alkyl group or an aryl group. When any of R ^{1 to} R ³ is an alkyl group or an aryl group, the alkyl group or the aryl group may be substituted, and examples of the substituent include a methyl group, an ethyl group, a methoxy group, and a chloromethyl group. Group, phenyl group, tolyl group and the like.

In the general formula (2), R ⁴ is a halogen atom,
Alkyl group, aryl group, alkoxyl group, acyl group,
It represents an acyloxy group or an alkoxylcarbonyl group. When R ⁴ is an alkyl group, an aryl group, an alkoxyl group, an acyl group, an acyloxy group, or an alkoxyl carbonyl group, R ⁴ may be substituted, and the substituent may be a halogen atom, a phenyl group, or the like. No. When R ⁴ is an alkyl group, an alkoxy group, an acyl group, or an alkoxycarbonyl group, the number of carbon atoms is preferably 1 to 18. When R ⁴ is an aryl group,
Examples of the aryl group include a phenyl group, a naphthyl group and pyrenyl.

The lower the polarity of the insulating block, the better the charge transporting property. The polarity of the insulating block, in the polymer of vinyl monomer,
Governed by the dipole moment of the hydrogenated form of the vinyl monomer to the vinyl group, wherein the dipole moment is 2
D or less, more preferably 1.5 D or less, even more preferably 1 D or less.

In the general formula (2), R ^{1 to} R ³ are a hydrogen atom or an alkyl group, and R ⁴ is an alkyl group, an aryl group, an alkyl-substituted aryl group, or an aryl-substituted alkyl group. Is particularly preferable since the dipole moment of the hydrogenated product is 1D or less.

The glass transition point of the insulating block is preferably 30 ° C. or higher, more preferably 60 ° C. or higher, even more preferably 90 ° C. or higher from the viewpoints of mechanical strength, surface contamination resistance and the like. The insulating block preferably has a formula weight of 2,000 or more from the viewpoint of exhibiting polymer characteristics such as film-forming properties and phase separation properties.

The charge transport material needs to be formed by block copolymerization or graft copolymerization of a charge transport compound having a repeating unit represented by the general formula (1) and an insulating compound. In the case where the charge transport material is not a block copolymer or a graft copolymer, but is a mere homopolymer / random copolymer, various characteristics of the insulating block are controlled without affecting the charge transport ability. Is difficult.

On the other hand, if the charge transporting material is a block copolymer or a graft copolymer of a charge transporting compound having a repeating unit represented by the general formula (1) and an insulating compound, The connection form of the constituent blocks may be any. As a connection form of the constituent blocks, for example, the charge transporting block is represented by “A”,
When the insulating block is "B", AB type, ABA
Type, BAB type, (AB) n type, (AB) nA type, and B
(AB) n-type block copolymer, graft copolymer having a charge transporting block as a main chain and an insulating block as a side chain, graft copolymer having an insulating block as a main chain and a charge transporting block as a side chain Examples include a polymer or a block-graft copolymer obtained by grafting A and / or B to a side chain of a block copolymer such as an ABA type.

In producing the charge transport material, the mixing ratio of the charge transport compound and the insulating compound is as follows:
The composition ratio of the charge transporting block and the insulating block (charge transporting block / insulating block) in the generated charge transporting material is determined by the volume ratio of the charge transporting domain and the electrically inert matrix (charge transporting domain). / Electrically inert matrix), and is preferably adjusted arbitrarily so as to fall within the numerical range described later.

As a method for synthesizing the charge transport material, for example, “Fourth Edition Experimental Chemistry Course 28 Polymer Synthesis (Maruzen, 1
992), "Chemistry and Industry of Macromonomer (IPC, 1990)", "Compatibility of Polymer and Evaluation Technology (Technical Information Association, 1992)", "New Polymer One P
oint 12 polymer alloy (Kyoritsu, 1988) ",
"Angew. Macromol. Chem., 14
3, pp. 1-9 (1986) "," Journal of the Adhesion Society of Japan,
26, pp. 112-118 (1990) "," Mac
romolecules, 28, pp. 4893-48
98 (1995) "," J. Am. Chem. So
c. , 111, pp. 7641-7643 (198
9) "and" JP-A-6-83077 ". Any suitable synthesis method capable of providing a block copolymer or a graft copolymer can be mentioned.

For example, a desired block copolymer can be obtained by previously synthesizing a charge transporting polymer and an insulating polymer and reacting and bonding the polymers.
Further, the polymerization form of the monomer forming the charge transporting block and the monomer forming the insulating block is the same,
If the reactivity of the two is significantly different, simply polymerizing a mixture of these monomers first polymerizes the more reactive monomer, and after the monomer is consumed, the less reactive one is used. Is polymerized to obtain a desired block copolymer. Further, a polymer of one of the monomers is synthesized in advance, and azo, peroxyester, peroxy, dithiocarbamate,
A desired block copolymer or graft copolymer can also be obtained by introducing a polymerization initiator containing a group having a polymerization initiation ability, such as an alkali metal alcoholate or an alkali metal alkyl, and polymerizing the other monomer with the polymerization initiator. A polymer is obtained. According to this method, a block copolymer or a graft copolymer composed of a polycondensation or polyaddition polymer and an addition polymerization or ring-opening polymerization polymer can be easily obtained. Furthermore, a compound containing a plurality of groups having a polymerization initiating ability such as azo, peracid ester, peroxy, etc. in a molecule is used. First, one monomer is polymerized from a part of the polymerization initiating groups, and then the remaining polymerization is performed. The desired block copolymer can also be obtained by polymerizing the other monomer from the initiating group.

Furthermore, a desired block copolymer can also be obtained by sequentially polymerizing each monomer by a living polymerization method such as a cation living polymerization method, an anion living polymerization method, or a radical living polymerization method. The living polymerization method has an advantage that the molecular weight of each block can be easily controlled and a polymer having a narrow molecular weight distribution can be obtained. Furthermore, immortal polymerization method, Inifer
The desired block copolymer can also be obtained by sequentially polymerizing each monomer by a ter method or the like. Furthermore, a desired graft copolymer can be obtained by synthesizing a macromonomer in which the other monomer has been introduced into the terminal of a polymer of one monomer in advance, and polymerizing the macromonomer.

In the general formula (1), when the reactive group is a hydroxymethyl group, for example, after block copolymerization, a formyl group is introduced into the aromatic ring by the Vilsmeier method and then reduced, whereby the aromatic group is reduced. A hydroxymethyl group can be introduced into the ring. It is also possible to introduce a formyl group into the charge transporting polymer in advance and reduce the formyl group after copolymerization to obtain a hydroxymethyl form. At this time, sodium borohydride or the like is preferable as the reducing agent to be used, since it can be reacted under relatively mild conditions and the post-treatment can be easily purified. Further, by controlling the reaction conditions for formylation, the number of hydroxymethyl groups introduced into the aromatic ring can be controlled.

The molecular weight (weight average molecular weight) of the charge transporting material is not particularly limited, but is preferably 2,000 or more, more preferably 10,000 or more, from the viewpoint of exhibiting polymer characteristics such as film-forming properties and phase separation properties. Is more preferable, and 20,000 or more is further preferable. The upper limit of the molecular weight of the charge transporting material is not particularly limited in terms of electrical characteristics. However, when the charge transporting layer is formed by a wet coating method, the upper limit of the molecular weight is within a range that gives an appropriate solution viscosity. Is generally required, and is preferably 5,000,000 or less.

As is well known in the art of polymer blends and polymer alloys, different polymers are generally
They are incompatible with each other, and their mixtures and block copolymers or graft copolymers are in a phase separated state. In general, a simple mixture, that is, a polymer blend, has a macroscopic phase separation scale of several μm or more (macrophase separation). On the other hand, a block copolymer or a graft copolymer in which each component is connected by a covalent bond gives a phase separation state composed of fine domains of submicron or less (microphase separation). It is known that the scale of phase separation in block copolymers and graft copolymers is generally of the same dimension as the average length of each block and is approximately proportional to the formula weight of each block.

The charge transporting material also generally takes a micro phase separated state. However, the charge transporting material is not necessarily in a micro phase-separated state, but may exhibit compatibility and not cause phase separation depending on the combination of each block. In general, the compatibility increases as the molecular weight (formula weight of each block) decreases and as the difference between the solubility parameters decreases.

The above-described charge transporting material has both high charge transporting ability and excellent mechanical properties. Therefore, it is suitably used for various organic electronic devices. It is suitable as a charge transport material for various organic electronic devices such as organic EL devices, organic photorefractive devices, and organic optical sensors. In particular, it is suitably used for a function-separated type electrophotographic photosensitive member.

For example, a material having both high charge transporting property, film forming property, adsorbing property to pigment and adhesive property can be used in combination with a pigment having charge generating ability to provide an excellent single-layer type photoreceptor, Provides a charge generating layer for a stacked photoreceptor. Further, a material having both high charge transportability, mechanical strength, chemical strength and low surface energy is effective as a material for a charge transport layer or a surface protective layer. In particular, when a hydroxymethyl group is introduced as a reactive group into the charge transporting block, isocyanate or alkoxysilanes are added and crosslinked and cured to give a very tough charge transporting film and a surface protective layer. Is also effective.

Further, those which provide a micro phase separation state in which the charge transporting block is a domain and the insulating block is a matrix are suitable as a non-uniform charge transporting layer for a functionally separated S-shaped photoreceptor. In particular, when the charge-transport block and the insulating block are incompatible, a submicron-scale microphase-separated structure is provided, and a stacked photoconductor using the same as a non-uniform charge-transport layer is: It functions as an excellent S-shaped photoconductor, and can fundamentally solve the problems and problems of the conventional S-shaped photoconductor described above. Furthermore, by co-polymerizing a component exhibiting other desired characteristics as the insulating block, it is possible to develop a further highly functional material.

-Conductive Support-The conductive support can be selected from any type that can be used as such a support in the art, and may be opaque or substantially transparent. Specific examples of the conductive support include metals such as aluminum, nickel, and stainless steel, and aluminum, titanium, nickel, chromium, stainless steel, gold, platinum, zirconium, vanadium, tin oxide, indium oxide, and ITO. And plastics, glass and ceramics provided with a thin film such as, or paper, plastic, glass and ceramics coated or impregnated with a conductivity-imparting agent. These conductive supports can be used in an appropriate shape such as a drum shape, a sheet shape, and a plate shape.

Further, the surface of the conductive support can be subjected to various treatments as required. For example, surface oxidation treatment, chemical treatment, coloring treatment, or mechanical roughening treatment such as graining and honing may be mentioned.
The oxidation treatment and mechanical surface roughening treatment of the conductive support surface not only roughens the conductive support surface, but also controls the surface shape of the layer applied thereon, and is used as a light source for exposure. An effect of preventing the occurrence of interference fringes due to regular reflection at the surface of the support and / or at the interface of the laminate, which is a problem when using a coherent light source such as a laser, is exhibited.

-Layer Configuration of Electrophotographic Photoreceptor of the Present Invention- FIGS. 3 to 6 are schematic enlarged sectional views showing an example of the layer configuration of the electrophotographic photoreceptor of the present invention. In FIG. 3, an electrophotographic photoreceptor 10 has a charge generation layer 2 on a conductive support 1.
And a non-uniform charge transport layer 3 for carrying out S-shape and charge transport. In FIG. 4, an electrophotographic photoreceptor 10 ′ is placed on a conductive support 1 ′.
Charge generation layer 2 'and non-uniform charge transport layer 3' responsible for S-shaped formation
And a uniform charge transport layer 4 that mainly performs charge transport. In FIG. 5, an electrophotographic photoreceptor 10 ″ is a laminated electrophotographic photoreceptor having a non-uniform charge transport layer 3 ″ and a charge generation layer 2 ″ sequentially on a conductive support 1 ″. Body. In FIG.
The electrophotographic photoreceptor 10 '''has a uniform charge transport layer 4' and a non-uniform charge transport layer 3 '''on a conductive support 1'''.
And a charge generation layer 2 ′ ″.

However, an appropriate intermediate layer may be provided between the charge generation layer and the non-uniform charge transport layer for the purpose of injecting charges and assisting the generation of charges. Further, by inserting a uniform charge transport layer between the charge generation layer and the heterogeneous charge transport layer and changing the thickness of the uniform charge transport layer, the E _50% / E _10% value described It is also possible to set any value within the range.

The layer constitution of the electrophotographic photosensitive member of the present invention may be either a single layer constitution or a laminated constitution. In particular, an electrophotographic photosensitive member having a laminated constitution is excellent in that it exhibits excellent S-shaped photoinduced potential decay characteristics. Photoreceptors are preferred. In addition, it has a charge generation layer, a non-uniform charge transport layer, and a uniform charge transport layer as described above. With layers)
Is more preferred. When the electrophotographic photoreceptor has a laminated structure, the charge generated in the charge generation layer encounters a failure in the electrically inactive matrix of the heterogeneous charge transport layer, and the distance traveled until the charge is temporarily stopped for the first time. If the thickness is sufficiently small with respect to the total thickness, the potential decay therebetween becomes negligible, and a more ideal S-shaped characteristic is exhibited. Therefore, the electrophotographic photoreceptor having the structure shown in FIGS. 4 and 6 in which the charge generation layer and the non-uniform charge transport layer for forming an S-shape are close to each other provides better S-shape. Furthermore, it is particularly preferred that the charge transport material is contained in the heterogeneous charge transport layer.

Here, the mechanism of the development of the S-shaped photoinduced potential decay characteristic will be described. Regarding the mechanism of the S-shaped photoinduced potential decay characteristics, the trap theory is described, for example, Kitamura, Komon:
Journal of the Society of Electrophotography, Vol. 20, p. 60 (198
2) Δ, D. M. Although there are some proposals such as the convolutional conduction theory proposed by Pai et al. In the above patent, there is no established theory yet. However, the above-described pigment resin dispersion type single-layer photoconductor, which has been reported as an S-shaped photoconductor,
D. M. In a laminated photoreceptor comprising a charge generation layer such as Pai and a non-uniform charge transport layer, and a laminated photoreceptor comprising a charge generation layer such as the author, a heterogeneous charge transport layer and a uniform charge transport layer, at least adjacent to the charge generation region It can be recognized in common that the charge transport path of the charge transport region has a non-uniform structure in which charge transport domains are dispersed in an electrically inert matrix. In addition, the electrical inertness here means that the transport energy level is largely different from the transport energy level of the charge transport domain, and at a normal electric field intensity, the transport charge is substantially not injected, It means that the transport charge is in a practically electrically insulating state.

In the present invention, the reason why the laminated photoreceptor using a phase-separated heterogeneous charge transport layer containing a copolymer composed of an incompatible charge transport block and an insulating block is S-shaped light Although it is not always clear whether or not it exhibits the evoked potential decay characteristic, D.I. M. According to the convolutional conduction theory proposed by Pai et al., It is estimated that the process in which the S-shaped photoinduced potential decay occurs is as follows.

First, in the heterogeneous charge transport layer, it is considered that the charge transport domains dispersed in the electrically inactive matrix are in contact with each other to form a convoluted charge transport path. In this case, when the electrophotographic photoreceptor is charged and a high electric field is applied to the photosensitive layer, the charges generated in the charge generation layer by the exposure are injected from the charge generation layer into the charge transport layer along the electric field due to the Coulomb force due to the electric field. And move in the direction of the electric field in the charge transporting domain. However, when reaching the terminal convex portion of the charge transporting domain, it encounters a barrier of an electrically inactive matrix, and the movement direction is regulated by the electric field, so that the movement of the charge is temporarily stopped here. .

If the moving distance during this period is sufficiently small with respect to the total thickness of the photosensitive layer, the potential decay during this period can be ignored. After charges corresponding to almost all surface charges have been injected, the local electric field perpendicular to the surface near the injected charges becomes negligible, and the stopped electric charge escapes the binding by the electric field and is perpendicular to the surface. It is possible to diffuse in a direction other than the desired direction, and reaches a deeper portion than the place where the charge is first stopped by following the convoluted connecting path. At this depth, as before, the charge is again exposed to a sufficiently high electric field, travels in the domain along the direction of the electric field, again encounters the barrier of the electrically inert matrix, and stops moving. However, since the electric field strength has decreased due to the previous charge transfer, more charge reaches the next insulating barrier through the convoluted charge transport path. Thus, the transfer of charges occurs in a cascade, resulting in an S-shaped photoinduced potential decay, according to D.S. M. It is an explanation by Pai and the like.

In the single-layer S-shaped photoreceptor of the pigment resin dispersion type, since the exposure light is absorbed near the surface and charges are generated there, the light absorption / charge generation region is defined as a charge generation layer.
The remaining area that follows can be considered as a charge transport layer, and the above description also applies.

In the present invention, a laminated photoreceptor using a phase-separated heterogeneous charge transporting layer containing a copolymer composed of an incompatible charge transporting block and an insulating block is described as follows.
The shape of the photo-induced potential decay behavior in the shape of a letter also shows that the phase composed of the charge transporting block forms the charge transporting domain, and the phase composed of the insulating block forms the electrically inactive matrix, and the above phenomenon occurs It is presumed that the maximum scope of the present invention is not limited by theory.

The S-shaped measure of the photo-induced potential decay characteristic includes, for example, the exposure amount (E _50% ) required to attenuate the charged potential by 50% (hereinafter simply referred to as “E _50% ”). And the exposure required to attenuate it by _10% (E _10% )
(Hereinafter sometimes simply referred to as “E _10% ”) (E _50% / E _10% ). If the potential decay is proportional to the exposure in an ideal J-shaped photoreceptor,
_The value of _50% / E _10% is 5. In a general J-shaped photoreceptor,
Since the charge generation efficiency and / or the charge transporting ability decrease as the electric field intensity decreases, the E _50% / E _10% value exceeds 5. On the other hand, in the S-shaped ultimate, a step-like light-induced potential decay curve in which the potential does not attenuate at all until a certain exposure amount and the potential attenuates at a stretch to the residual potential level at that exposure amount,
The value of E _50% / E _10% is 1. Therefore, the S-shape is E
_{The 50%} / E _10% value is defined as showing a value of 1 or more and less than 5. In order to exhibit the above-mentioned preferable digital characteristics, the value of E _50% / E _10% is preferably less than 3, more preferably less than 2. However, when using analog characteristics together for reasons such as enhancing the gradation,
E50 _% / E10 _% values give good results in the range of approximately 1.5-4. The S-shaped electrophotographic photoreceptor of the present invention can provide such a preferable E50 _% / E10 _% value.

-Each layer in the case where the electrophotographic photosensitive member of the present invention has a laminated structure- When the electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member having a laminated structure, the photosensitive layer includes a charge generating layer, It has a charge transport layer and, if necessary, other layers.

--- Charge Generation Layer-- In the charge generation layer, irrespective of J-shape or S-shape,
Any charge generation material that can be used as a charge generation layer can be used for the electrophotographic photoreceptor having a laminated structure. Examples of the charge generation material include amorphous selenium, selenium-tellurium alloy, selenium-arsenic alloy, other selenium compounds and selenium alloys, zinc oxide, titanium oxide, a-Si,
Inorganic photoconductive materials such as a-SiC, phthalocyanine-based, squarium-based, anthantrone-based, perylene-based, azo-based, anthraquinone-based, pyrene-based, pyrylium-salt-based, organic pigments and dyes, and the like. Can be

Among these, the phthalocyanine compounds are particularly preferable because they have excellent photosensitivity at 600 to 850 nm, which is the emission wavelength of LEDs and laser diodes, which are currently widely used as light sources in digital electrophotographic devices. . Examples of the phthalocyanine-based compound include metal-free phthalocyanine, metal phthalocyanine, and derivatives thereof. As the central metal of the metal phthalocyanine, Cu, Ni, Zn, Co, Fe,
V, Si, Al, Sn, Ge, Ti, In, Ga, M
g, Pb, Li, etc., and also oxides, hydroxides, halides, alkylated compounds, alkoxylated compounds, etc. of these central metals.

Specific examples of the phthalocyanine compound include titanyl phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, vanadyl phthalocyanine, chloroindium phthalocyanine, dichlorotin phthalocyanine, dimethoxysilicon phthalocyanine and the like. Also, substituted phthalocyanines in which an arbitrary substituent is introduced into the phthalocyanine ring of the above compound can be used. Further, azaphthalocyanines in which an arbitrary carbon atom in the phthalocyanine ring of the above compound is substituted with a nitrogen atom are also effective. As the form of these phthalocyanine compounds, it is possible to use amorphous or all crystalline forms. Among these phthalocyanine-based compounds, metal-free phthalocyanine, titanyl phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, and dichlorotin phthalocyanine have particularly excellent photosensitivity and are particularly preferable.

Most of the phthalocyanine compounds are
Dichlorotin phthalocyanine, phthalocyanines having an electron-withdrawing group, and azaphthalocyanines have the property of a p-type semiconductor in which holes are the main transport charge. Therefore, the S-shaped photoreceptor containing these phthalocyanine-based compounds as a charge generation material and sequentially laminating a charge generation layer and a charge transport layer on a conductive substrate was used with a negative charge. In this case, good electrophotographic properties such as high sensitivity, low injection of positive charges from the conductive support, low dark decay and high chargeability are exhibited.

Further, hexagonal selenium, anthraquinone pigments and perylene pigments are also excellent in charge generation efficiency, and thus can be suitably used as charge generation materials. Since the beam diameter of the laser beam can be reduced as the transmission wavelength becomes shorter, studies have been made on shortening the wavelength of the exposure laser with the aim of further improving image quality, but these compounds are visible from the ultraviolet region. Since it has photosensitivity in the region, it can be particularly preferably used as a charge generation material for a short wavelength laser. These charge generation materials may be used alone or in combination of two or more.

The charge generation layer can be formed by a method in which the charge generation material is directly formed into a film by a vacuum evaporation method, or a method in which the charge generation material is dispersed or dissolved in a binder resin. When a binder resin is used for the charge generation layer, the type of the binder resin is not particularly limited, and examples thereof include, for example, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal resin, polycarbonate resin, polyester resin, and acrylic resin. Resin, polyvinyl chloride resin, polystyrene resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate copolymer, silicone resin, phenol resin, polyvinyl carbazole resin and the like.

These binder resins may be block, random or alternating copolymers. Further, the above-described charge transport material is also effective as a binder resin for the charge generation layer. These binder resins may be used alone or in combination of two or more.

In the charge generation layer, the compounding ratio (volume ratio) of the charge generation material to the binder resin (charge generation material / binder resin) is preferably from 10/1 to 1/10, and more preferably from 3/1. 1 to 1/1 is more preferable. When the compounding ratio of the charge generation material to the binder resin exceeds the above-mentioned numerical range, dark decay may increase, and a layer having a uniform thickness may not be obtained by the wet coating method. Otherwise, obstacles such as a decrease in photosensitivity and an increase in residual potential may occur.

The charge generation layer is preferably formed by dispersing and dissolving the charge generation material, the binder resin and the like in a predetermined solvent to form a coating solution for the charge generation layer. Examples of the predetermined solvent include chlorobenzene, butyl acetate, ethyl acetate, tetrahydrofuran, cyclohexanone, acetone, methyl ethyl ketone, toluene, xylene, methanol, ethanol, propanol and the like. These may be used alone or in combination of two or more.

The thickness of the charge generation layer is generally from 0.05 to 5 μm, preferably from 0.1 to 5 μm.
It is set in the range of ２．０2.0 μm.

The method for forming the charge generating layer by coating is as follows.
Usable coating methods such as blade coating, wire bar coating, spray coating, dip coating, bead coating, air knife coating, and curtain coating are used.

--- Charge Transport Layer-- The charge transport layer preferably has a heterogeneous charge transport layer and a uniform charge transport layer as described above. <Nonuniform (S-shaped) charge transport layer> The non-uniform charge transport layer (S-shaped charge transport layer, hereinafter sometimes referred to as “S-shaped charge transport layer”) is an electrically inactive matrix. A layer forming a charge transport path characterized by a non-uniform structure in which charge transport domains are dispersed therein, and any suitable method can be adopted for the formation thereof.

For example, a substance having a charge transporting property, for example, fine particles having a charge transporting property (hereinafter referred to as charge transporting fine particles) is dispersed in a solution in which an insulating binder resin is dissolved in a suitable solvent. After being applied by a dip coating method or the like, it can be obtained by drying. Also,
The charge transporting fine particles previously insolubilized by coating with a crosslinking compound such as a thermosetting resin or a silane coupling agent are dispersed in a solution in which an insulating binder resin is dissolved in an appropriate solvent, followed by dip coating. Etc., followed by drying. Furthermore,
It can also be obtained by precipitating microcrystals of a charge transporting material by subjecting a substance in which a substance having a charge transporting property is uniformly dispersed in an insulating binder resin to heat treatment, solvent treatment, or the like. Further, in a block copolymer or a graft copolymer (a substance having a charge transporting ability) comprising an insulating block and a charge transporting block, microphase separation in which the insulating block is a matrix and the charge transporting block is a domain. Stateful systems can also be used.

Examples of the solvent include chlorobenzene, butyl acetate, ethyl acetate, tetrahydrofuran, cyclohexanone, acetone, methyl ethyl ketone, toluene, xylene, methanol, ethanol, propanol and the like. These may be used alone or in combination of two or more.

In these methods of forming the S-shaped charge transport layer, the formation of the convoluted charge transport path depends on the stochastic contact between the charge transport domains. If the probability of the contact is too high, the charge transport path will not be convoluted and the S-shaped property will decrease.If the probability of the contact is too low, a continuous charge transport path through the entire charge transport layer cannot be formed. , Causing an increase in the residual potential. The contacts of the charge transport domains are
Not necessarily in direct contact, a very thin insulating layer between the charge transporting domains is acceptable if charge can jump over that gap and negligible trapping there. Here, the convoluted charge transport path is a charge transport path that is formed such that the movement of charges is reversed at least once in the film thickness direction.

The above-described charge transporting material having a charge transporting block and an insulating block effectively functions as an S-shaped charge transporting layer when these blocks are incompatible with each other. Therefore, in the present invention, it is preferable that the above-mentioned charge transporting material contains the above-described charge transporting material as a main component from the viewpoint of forming an S-shape.

[0108] In the heterogeneous charge transport layer, as the insulating block forming the electrically inactive matrix, to the main transport charge, but it may be any electrically inactive, 10 ¹³ Omega Cm or more, and more preferably 10 ¹⁴ Ω · cm or more. If the volume resistivity is less than the above numerical range, the electrical insulation of the electrically inactive matrix tends to be impaired, and the S-shaped characteristic tends to be lost and dark decay tends to increase.

Specific examples of the insulating block include polyalkyl methacrylate, polyalkyl acrylate, polyvinyl chloride, polystyrene, polyalkyl vinyl ether, polycarbonate, polyester, and the like, and those blocks, grafts, random, or alternate copolymers. In particular, a polymer obtained by polymerizing at least one kind of the vinyl monomer represented by the general formula (2) can be used in view of mechanical strength, flexibility, phase separation property, and the like. Are particularly preferred.

In the heterogeneous charge-transporting layer, any charge-transporting block that forms the charge-transporting domain may be used as long as it has a charge-transporting ability, but it preferably has a triarylamine structure. It is preferable in terms of charge transport properties, chemical stability and the like, and particularly preferably contains a charge transport compound having a repeating unit represented by the above general formula (1). In this case, depending on the solvent of the coating liquid for forming the upper layer of the heterogeneous charge transport layer, the charge transportable block portion of the heterogeneous charge transport layer swells, causing a decrease in phase separation, and a sufficient degree of S-shape. May not be obtained. In that case, a hydroxymethyl group (reactive group)
However, it is effective to add 1/100 to 10 equivalents of a curable monomer to cause crosslinking, and 1/10 to 1 equivalent is preferable.

Examples of the curable monomer include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate, tolidine diisocyanate, 1,6-hexamethylene diisocyanate, xylene diisocyanate, lysine diisocyanate, and tetramethyl isocyanate. Urethane monomers such as xylene diisocyanate, or trimethoxy lan, triethoxy silane, dimethoxy silane,
Alkoxysilanes such as diethoxysilane are effective, but not limited thereto. In some cases, it is possible to crosslink with dehydration of the hydroxymethyl group by heat or acid.

In the charge transporting material, the composition ratio of the charge transporting block and the insulating block (charge transporting block / insulating block) may be different from the charge transporting domain obtained as a result of their phase separation and the electric charge transporting block. The volume ratio to the inert matrix (charge transporting domain / electrically inert matrix) is arbitrarily set within a range of 10/1 to 1/10. The volume ratio is 4/1 to 1
/ 2 is more preferred.

When the volume ratio of the charge transporting domain to the electrically inert matrix exceeds the above numerical range, the charge transporting domains come into close contact with each other or the charge transporting blocks form a matrix. A charge transport path having a uniform structure is formed, and the above-mentioned non-uniform structure of the charge transport path, which is indispensable for exhibiting the S-shaped photoinduced potential decay characteristic, may be lost, and the S-shaped property may be lost. On the other hand, the volume ratio of the charge transporting domain is less than the numerical range,
The charge transport path is disconnected, which may cause an obstacle such as an increase in residual potential and a decrease in response speed.

As the phase separation structure of the heterogeneous charge transport layer, any structure may be used as long as the charge transport block serves as a domain and the insulating block serves as a matrix. In a case where a phase separation structure is adopted in which the phase composed of islands and the phase composed of insulating blocks become the sea, more excellent S-characteristics can be obtained. Also, when a modulation structure obtained by spinodal decomposition is employed, a favorable S-shaped characteristic can be obtained.

As the phase separation structure, the most thermodynamically stable structure exists depending on the type and molecular weight of the constituent blocks. In general, for example, in a copolymer composed of A block and B block, A / B
Depends only on the composition ratio, and as the A / B ratio increases, A is a spherical domain and B is a matrix, A is a rod-shaped domain and B is a matrix, A / B alternating layers, B is a spherical domain and A is a matrix, B Is a rod domain and A is systematically transformed into a matrix. However, when the layer is formed by a wet coating method, the phase separation structure can be arbitrarily controlled depending on the solvent used, the drying speed, and the like. For example, even when the A / B ratio is large and a B-sphere A matrix is taken thermodynamically, if a solvent that is a good solvent for B and a poor solvent for A is selected as a coating solvent, A
A spherical B matrix structure can be obtained.

Further, when a good solvent of both A and B is used and the solvent is rapidly removed, a phase separation structure (modulation structure) frozen in a spinodal decomposition state can be obtained. Furthermore,
When a polymer having a large A / B ratio and having a thermodynamically B-sphere A matrix and a polymer that is compatible only with B is added, A becomes a sphere and a polymer that is compatible only with B and B. It is also possible to obtain a phase-separated structure in which coalescence forms a matrix.

The thickness of the non-uniform (S-shaped) charge transport layer is suitably from 0.1 to 50 μm, and from 0.2 to 15 μm.
μm is preferred, and 0.5-5 μm is more preferred. If the thickness is less than the numerical range, the S-shaped property may be reduced. The upper limit of the thickness is limited by the charge transporting ability of the S-shaped charge transporting layer to be used, and the response speed, the residual potential, and the like are set within allowable ranges.

The volume average particle diameter of the charge transporting domain is preferably from 0.005 to 3 μm, more preferably from 0.01 to 3 μm.
1 μm is more preferred, and 0.02 to 0.5 μm is even more preferred. When the average particle size exceeds the numerical range,
Within the preferable range of the thickness of the layer, the probability of forming a non-uniform structure of the charge transport path required for forming the S-shape is reduced, and the S-shape may be reduced. On the other hand, if the average particle diameter is less than the above numerical range, the charge transport path may approach a uniform structure, and the S-shaped property may be reduced.

The charge mobility of the charge transporting domain is as follows:
It is one factor that governs the response speed of the electrophotographic photosensitive member, and the higher the mobility, the more suitably it is used for a high-speed electrophotographic apparatus. When the electrophotographic photoreceptor of the present invention is used in an electrophotographic apparatus, the charge mobility is preferably at least 10 ⁻⁶ cm ² / Vs, and more preferably 5 × 10 ⁻⁶ cm ² , in an electric field intensity range used for development. / Vs or more is more preferable.
Incidentally, it is difficult to directly measure the charge mobility,
The charge mobility of a charge transporting polymer having the same structure as the charge transporting block can be used instead. The measurement of the charge mobility is a common method in the art, "Time-of-F
Light method ”.

Further, by adding a compound capable of transporting only a charge having a polarity opposite to that of the main transport charge to the S-shaped charge transport layer, effects such as reduction of residual potential and improvement of repetition stability can be obtained. You can also.

Further, a charge transporting polymer and / or an insulating polymer can be added to the S-shaped charge transporting layer. When a charge transporting polymer is added, the charge transporting polymer preferably has compatibility with the charge transporting block in the above-described charge transporting material. When an insulating polymer is added, it is preferable that the polymer has compatibility with the insulating block in the above-described charge transporting material.

The method of applying and forming the above-mentioned heterogeneous charge transporting layer includes blade coating, wire bar coating, spray coating, dip coating, and the like.
Bead coating method, air knife coating method,
An ordinary method such as a curtain coating method can be used. The coating solution may be a uniform solution or a micelle solution.

<Uniform charge transport layer> When the uniform charge transport layer is provided in the electrophotographic photosensitive member, the material of the uniform charge transport layer may be used in the art for the charge transport layer of the J-shaped laminated photosensitive member. Can be selected from any of the materials listed.

Examples of the material for the uniform charge transport layer include benzidine compounds, amine compounds, hydrazone compounds, stilbene compounds, and carbazole compounds. These may be used alone or in combination of two or more, and may be an insulating resin (for example,
Polycarbonate, polyarylate, polyester, polysulfone, polymethyl methacrylate, etc.) may be used as a solid solution film in which molecules are uniformly dispersed. Alternatively, a high molecular compound or the like having a charge transport ability itself may be used,
Further, an inorganic substance having a charge transporting property such as selenium, a-Si, a-SiC, or the like can also be used.

Examples of the polymer compound having a charge transporting ability (charge transporting property) include a polymer compound having a group having a charge transporting ability such as polyvinylcarbazole in a side chain;
Examples include a polymer compound having a group having a charge transporting ability in the main chain thereof as disclosed in Japanese Patent No. 232727 and the like, and polysilane.

As the material of the uniform charge transporting layer, a charge transporting polymer compound is preferable, particularly from the viewpoint of production. That is, when a heterogeneous charge transport layer and a uniform charge transport layer are stacked and formed, if a charge transportable low molecular weight compound is used in the uniform charge transport layer, the charge transportable low molecular weight compound is added to the heterogeneous charge transport layer. The S-shaped property is impaired due to a decrease in the insulating property of the electrically inactive matrix of the heterogeneous charge transport layer against the main charge, or the charge transport property mixed into the heterogeneous charge transport layer is low. Molecules may become charge traps in the heterogeneous charge transport layer, causing problems such as an increase in residual potential, a decrease in transport ability, and a decrease in photosensitivity.

This problem is particularly remarkable when each layer is formed by a wet coating method. (Of course, these problems are caused by selecting a solvent which hardly dissolves and swells the lower layer as a coating solvent for the upper layer, or This can be avoided by making the heterogeneous charge transporting layer cross-linkable and curable so as not to dissolve or swell with the upper layer coating solvent).

However, as described above, it is known that it is common for polymers to undergo phase separation without being compatible with each other, and a charge transporting polymer compound is used as a uniform charge transport layer. In this case, since the phase separation occurs without being compatible with the resin of the heterogeneous charge transporting layer, the problem of the above-described mixing hardly occurs, and the advantage that the restriction on the selection of the material and the production method is eliminated. .

Further, as the charge-transporting polymer compound for the uniform charge-transporting layer, a charge-transporting resin containing at least one kind of the structure represented by the above general formula (1) as a repeating unit may be a high charge-transporting resin. It is particularly preferable because it has transportability and excellent mechanical properties. In particular, when a charge-transporting polymer having the same structure as the block used for the heterogeneous charge-transporting layer or the charge-transporting block of the graft copolymer is used for the uniform charge-transporting layer, the charge transfer layer changes from the heterogeneous charge-transporting layer to the uniform charge-transporting layer This makes the injection of the charge extremely smooth, which is particularly preferable.
Note that, in the uniform charge transport layer, there may be an electrically inactive region surrounded by the charge transporting matrix. For example, insulating particles having a low surface energy can be contained for the purpose of reducing the surface frictional force, reducing the abrasion, or reducing the adhesion of foreign substances to the surface. In addition, charge transporting fine particles and the like can be added to the uniform charge transport layer for the purpose of improving charge transport ability and the like.

[0130] Among the charge transporting materials, those in which the charge transporting block and the insulating block are compatible are as follows:
It can be effectively used in a uniform charge transport layer. Furthermore, as described above, in the uniform charge transport layer, there may be an electrically inactive region surrounded by the charge transport matrix, and therefore, among the charge transport materials, the charge transport block is a matrix, Those having a micro phase separation state in which the insulating block serves as a domain can also be used as the uniform charge transport layer. In the electrophotographic photoreceptor, in the case where the uniform charge transport layer is the outermost layer, it is preferable to use a cross-linkable curable material and use the formed uniform charge transport layer from the viewpoint of mechanical strength.

The uniform charge transport layer has a thickness of 50
μm is appropriate, and preferably 30 μm or less. As a method of forming the uniform charge transport layer by coating, it is preferable to disperse and dissolve the material of the uniform charge transport layer in a predetermined solvent and form the coating. As the predetermined solvent, chlorobenzene, butyl acetate, ethyl acetate, tetrahydrofuran,
Examples include cyclohexanone, acetone, methyl ethyl ketone, toluene, xylene, methanol, ethanol, propanol and the like. These may be used alone or in combination of two or more.

The method for forming the uniform charge transport layer is as follows.
Conventional methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method are exemplified. or,
Those capable of forming a vapor phase such as selenium can also be directly formed by a vacuum deposition method or the like.

The thickness of the entire charge transport layer including the heterogeneous charge transport layer and the uniform charge transport layer is suitably from 5 to 50 μm, and preferably from 10 to 40 μm.

In the electrophotographic photoreceptor, when the charge transport layer exists between the charge generation layer and the exposure light source,
It is desirable that the charge transport layer is substantially transparent to light at the exposure wavelength, in order to prevent a reduction in effective light sensitivity. Also,
The transmittance of light used for exposure in the charge transport layer is 50%.
Is preferably 70% or more, more preferably 90% or more. However, if use at low sensitivity is desired, a substance that absorbs light at the exposure wavelength can be added to adjust the effective light sensitivity.

--Other Layers-- The electrophotographic photoreceptor may have an undercoat layer, a protective layer,
It has a blocking layer, a diffuse reflection layer and the like. The undercoat layer,
Between the conductive support and the photosensitive layer, if desired,
One or more layers are provided. The undercoat layer serves as an adhesive layer for preventing the injection of electric charge from the conductive support to the photosensitive layer during charging of the photosensitive layer and for integrally bonding and holding the photosensitive layer to the conductive support. It has an action, and in some cases, an action of preventing regular reflection of light that causes interference fringes.

As the resin used for the undercoat layer, known resins can be used, for example, polyethylene resin,
Acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polyurethane resin, polyimide resin, vinylidene chloride resin, polyvinyl acetal resin, polyvinyl alcohol resin,
Water-soluble polyester resin, alcohol-soluble nylon resin, nitrocellulose, polyacrylic acid, polyacrylamide and other resins and their copolymers, or, zirconium alkoxide compounds, titanium alkoxide compounds,
A curable metal organic compound such as a silane coupling agent may be used. These resins may be used alone or in combination of two or more. Further, a material capable of transporting only charges having the same polarity as the charged polarity can be used.

The thickness of the undercoat layer is 0.01 to 1
0 μm is appropriate, and 0.05 to 5 μm is preferable. Examples of the method of forming the undercoat layer include ordinary methods such as a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method. .

The protective layer is formed of a photosensitive material that is exposed to chemical stress such as ozone or oxidizing gas generated from the charging member, ultraviolet light, or the like, or mechanical stress caused by contact with a developer, paper, a cleaning member, or the like. It is effective to protect the layer and improve the effective life of the photosensitive layer. In particular, the effect is remarkable in a layer configuration using a thin charge generation layer as an upper layer.

The protective layer is formed by including a conductive material in a suitable binder resin. Examples of the conductive material include metallocene compounds such as dimethyl ferrocene, antimony oxide, tin oxide, titanium oxide, indium oxide,
Examples include materials such as metal oxides such as TO, but are not limited thereto. Examples of the binder resin include known resins such as polyamide, polyurethane, polyester, polycarbonate, polystyrene, polyacrylamide, silicone resin, melamine resin, phenol resin, and epoxy resin. Also, a semiconductive inorganic film such as amorphous carbon can be used as the protective layer.

When these protective layers are resistance control type protective layers, their electrical resistances are 10 ⁹ to 10 ¹⁴ Ω ·
cm is preferred. When the electric resistance exceeds the above-mentioned numerical range, the residual potential increases. On the other hand, when the electric resistance does not exceed the above-mentioned numerical range, the charge leakage in the creeping direction cannot be ignored and the resolution is reduced. The thickness of the protective layer is suitably 0.5 to 20 μm, and 1 to 10 μm
Is preferred. When the protective layer is provided, a blocking layer for preventing leakage of electric charge from the protective layer to the photosensitive layer can be provided between the photosensitive layer and the protective layer, if necessary. As the material of the blocking layer, a known material can be used as in the case of the protective layer.

In the electrophotographic photoreceptor of the present invention described above, in order to prevent the photoreceptor from deteriorating due to ozone or oxidizing gas generated in the electrophotographic apparatus, or light or heat, each layer or the uppermost layer is formed. In addition, an antioxidant, a light stabilizer, a heat stabilizer and the like can be added. As the antioxidant, known agents can be used, and examples thereof include hindered phenol, hindered amine, paraphenylenediamine, hydroquinone, spirochroman, spiroidanone and derivatives thereof, organic sulfur compounds, and organic phosphorus compounds. Can be As the light stabilizer, known ones can be used, for example, derivatives such as benzophenone, benzotriazole, dithiocarbamate, and tetramethylpiperidine, and electron withdrawing that can deactivate the photoexcited state by energy transfer or charge transfer. Compounds or electron donating compounds. Furthermore, insulating particles having a low surface energy such as fluororesin may be dispersed in the outermost surface layer for the purpose of reducing surface wear, improving transferability, improving cleanability, and the like.

The electrophotographic photosensitive member of the present invention described above is
The degree of freedom in selection of physical properties and the like is high, the production is easy, the yield of the charge transport material at the time of production is high, and a high-quality image can be formed.

[Process Cartridge] The process cartridge is a cartridge in which some of the components of the electrophotographic apparatus are incorporated into the cartridge for the purpose of replacing expendable parts of the electrophotographic apparatus in a timely manner so that the replacement operation can be easily performed. is there. The process cartridge is traded in a state of being mounted in the electrophotographic apparatus, and is also traded alone as a replacement part or a repair part.

The components that can be incorporated into the process cartridge generally include a charging unit, a discharging unit, and a cleaning unit, and these can be arbitrarily combined according to the purpose.

The process cartridge of the present invention includes an electrophotographic photosensitive member, and at least one unit selected from the group consisting of a charging unit, a developing unit, a discharging unit, and a cleaning unit. Is the electrophotographic photoreceptor of the present invention. The components other than the electrophotographic photosensitive member that can be incorporated in the process cartridge are not particularly limited, and conventionally known components can be employed without any problem.

[Electrophotographic Apparatus] The electrophotographic apparatus on which the electrophotographic photosensitive member of the present invention is mounted may be of any type as long as it employs an electrophotographic method. A preferred electrophotographic apparatus is used. An electrophotographic apparatus that performs exposure based on a digitally processed image signal is an electrophotography that performs exposure in accordance with a multilevel signal by performing binarization or pulse width modulation or intensity modulation using a light source such as a laser or LED. Device
Examples include an LED printer, a laser printer, a laser exposure type digital copier, and the like.

E _{50% of the} electrophotographic photosensitive member of the present invention mounted
The value of / E _10% is preferably less than 5, more preferably less than 3, more preferably less than 2, in order to exhibit more preferable digital characteristics. Further, for the purpose of initializing the electrophotographic photosensitive member after development or stabilizing the electrophotographic characteristics, a light source can be used in addition to the exposure light source for image formation. The light emitting region of the light source may be one that is absorbed by the non-uniform charge transport layer or one that is not absorbed, but it is preferable that light reaches at least the charge generation layer.

FIG. 7 schematically shows a preferred example of the electrophotographic apparatus of the present invention. The electrophotographic apparatus shown in FIG. 7 is a laser printer. A pre-exposure light source (red LED) 12, a charging scorotron 13 as a charging unit, and an image exposure unit around a cylindrical photosensitive drum 11 as an electrophotographic photosensitive member. Exposure laser optical system 14 and developing device 1 as developing means
5. The transfer corotron 16 and the blade-type cleaning device 17 as cleaning means are arranged in this order. The exposure laser optical system 14 includes, for example, an exposure laser diode having an emission wavelength of 780 nm, and emits light based on digitally processed image signals.
The emitted laser light 14a is configured to expose the surface of the electrophotographic photosensitive member while being scanned by a polygon mirror, a plurality of lenses, and a mirror. Reference numeral 18 denotes a sheet.

In the electrophotographic apparatus of the present invention, the photosensitive drum 11 is the electrophotographic photosensitive member of the present invention. Of course, the photosensitive drum 11, the charging scorotron 13, and the developing device 1
5. a light source (red LED) 12 for pre-exposure and at least one means selected from the group consisting of a blade-type cleaning device 17, and the electrophotographic photoconductor is the electrophotographic photoconductor of the present invention. Alternatively, a configuration including a process cartridge may be used. In the process cartridge and the electrophotographic apparatus according to the present invention, instead of the non-contact charging type scorotron, a charging roll and a charging blade, which are contact charging type charging devices that directly contact and charge an electrophotographic photosensitive member, are used. Etc. may be used.

Although the electrophotographic apparatus of the present invention has been described with reference to the drawings, the present invention is not limited to such a configuration.
There is no particular limitation, and conventionally known products can be employed without any problem.

[0151]

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the following Examples, and those skilled in the art can make modifications to the following Examples based on known knowledge of synthetic polymer chemistry and electrophotographic technology.

[Synthesis Example 1-Reactive polymerization initiator: 4,4 '
-Synthesis of azobis (4-cyanovaleric chloride)] 140 ml of thionyl chloride was cooled with ice, and 4,4'-azobis (4
-Cyanovaleric acid) was gradually added. 30 ℃
For 6 hours, and excess thionyl chloride was distilled off under reduced pressure. After that, the residue was recrystallized from chloroform,
20 g of 4,4'-azobis (4-cyanovaleric acid chloride) crystals were obtained.

[Synthesis Example 2] N, N'-bis (m, m-dimethylphenyl) -N, N'-bis [p- (2-methoxycarbonylethyl) phenyl]-[p-terphenyl] -4 , 4 ″ -diamine 100 g, ethylene glycol 200 g, and tetrabutoxy titanium 0.2 g
Was heated to reflux under a nitrogen stream for 4 hours. Thereafter, the mixture was heated to 230 ° C. while distilling off excess ethylene glycol while gradually reducing the pressure to 0.5 mmHg, and the reaction was continued for 4 hours. Thereafter, the mixture was cooled to room temperature, methylene chloride was added to dissolve the insoluble matter, and precipitated in methanol, whereby 89 g of a prepolymer having hydroxy groups at both ends was obtained.
I got The weight average molecular weight of the obtained prepolymer is
It was 6.1 × 10 ⁴ .

40 g of the above prepolymer and 0.5 g of triethylamine were dissolved in 120 ml of dichloromethane.
This was cooled to below 0 ° C. A solution in which 5.6 g of 4,4′-azobis (4-cyanovaleric chloride) obtained in “Synthesis Example 1” was dissolved in 20 ml of dichloromethane was added dropwise. After reacting at room temperature for 1 hour, the reaction was carried out at 30 ° C. for 5 hours. Thereafter, the solvent was distilled off from this, tetrahydrofuran was added and dissolved, and methanol 500
Then, the mixture was stirred for 1 hour and filtered off. This reprecipitation operation was repeated twice more. The remaining compound was dried to obtain 31 g of a polymer having an azo-type polymerization initiator at both ends.

[Synthesis Example 3] 6 g of the polymer having an azo-type polymerization initiator at both ends obtained in “Synthesis Example 2” and 8 g of n-dodecyl methacrylate
Was dissolved in 120 ml of toluene, and after displacing with nitrogen, 6
Heated at 5 ° C. for 70 hours. The solvent was removed therefrom, tetrahydrofuran was added, and this solution was treated with 500 ml of methanol.
After stirring for 1 hour, the mixture was filtered off. The obtained solid was sufficiently washed with n-hexane and poly (n-
(Dodecyl methacrylate) was removed to obtain 10 g of a triblock copolymer. The weight average molecular weight of the obtained triblock copolymer is 8 × 10 ⁴ , and the weight composition ratio of the charge transporting block containing a triarylamine structure and the insulating block composed of poly (n-dodecyl methacrylate) ( Charge transporting block: insulating block) is ¹ H-N
From the analysis of the MR spectrum, it was calculated to be approximately 3: 2.

[Synthesis Example 4] 6 g of the triblock copolymer obtained in “Synthesis Example 3” was
Dissolve in 100 ml of methylene chloride and dissolve in 10 ml of DMF
5 g of dissolved phosphorus oxychloride was added dropwise over 20 minutes. So
After reacting for 5 days at room temperature, reprecipitated in methanol
The mixture was filtered and dried to obtain 4.8 g of an orange polymer.
Obtained polymer (formylated block copolymer
Body) was dissolved in 50 ml of THF, and kept at about 5 ° C. in an ice bath.
And cooled. To this, sodium borohydride 200m
g until the light color of the reaction mixture becomes pale yellow.
While stirring. Then, reprecipitate in methanol,
Block copolymer having a repeating unit represented by the formula
(Weight average molecular weight: 6.7 × 10 ^Four) Was obtained.
This is designated as "block copolymer 1".

Block copolymer 1

Embedded image

[Synthesis Example 5] 6 g of the polymer having an azo-type polymerization initiator at both ends obtained in “Synthesis Example 2” was dissolved in 120 ml of toluene, 25 g of styrene was added, and the mixture was purged with nitrogen.
Heated for hours. This is dropped into 500 ml of methanol,
The precipitated solid was separated by filtration and the filtrate was analyzed. As a result, a styrene copolymer was detected. Next, 13 g of the filtered solid (styrene copolymer) was finely pulverized, put into 2 L of xylene, and stirred for 24 hours to separate into an insoluble component and a soluble component. ¹
As a result of the H-NMR spectrum and GPC analysis, the soluble component was a block copolymer rich in unreacted charge transporting polymer and charge transporting block, and the insoluble component was the target block copolymer. The weight average molecular weight of the obtained block copolymer was 14 × 10 ⁴ . ^From the analysis of the ¹ H-NMR spectrum, the weight composition ratio of the charge transporting block and the insulating block of the target block copolymer (charge transporting block: insulating block) was about 35:65.

[Synthesis Example 6] The copolymer used in “Synthesis Example 4” (“Synthesis Example 3”)
"Synthesis example 4" except that the triblock copolymer obtained in the above was replaced with the block copolymer obtained in "Synthesis example 5".
In the same manner as in the above, a hydroxymethyl compound having a repeating unit represented by the following structural formula (weight average molecular weight: 11 × 1)
0 ⁴⁾ was synthesized. This is designated as "block copolymer 2".

Block copolymer 2

Embedded image

[Synthesis Example 7] In [Synthesis Example 2], N, N'-bis (m, m-dimethylphenyl) -N, N'-bis [p- (2-methoxycarbonylethyl) phenyl]-[ p-terphenyl]
-4,4 ″ -diamine is converted to 3,3′-dimethyl-N,
“Synthesis example 2” except that N′-biphenyl-N, N′-bis [4- (2-methoxycarbonylethyl) phenyl]-[1,1′-biphenyl] -4,4′-diamine was used. And further, in the same manner as in “Synthesis Example 3”, a block copolymer represented by the following structural formula was synthesized. The charge-transporting prepolymer having a triphenylamine structure has a weight average molecular weight of 9.1 × 10 ³ , and the finally obtained hydroxymethyl copolymer has a weight average molecular weight of 1.9 × 10 3.
⁴ , and the composition ratio between the charge transport block and the insulating block (charge transport block: insulating block) was calculated to be about 3: 2. Here, the obtained block copolymer is referred to as “block copolymer 3”.

Block copolymer 3

Embedded image

(Example 1) <Preparation of electrophotographic photoreceptor> -Formation of charge generation layer- In an X-ray diffraction spectrum using CuKα as a radiation source, at least the Bragg angle (2θ ± 0.2), 8.3 , 1
4 parts by weight of a dichlorotin phthalocyanine crystal having a strong diffraction peak at 3.7 and 28.3 were combined with 2 parts by weight of a polyvinyl butyral resin (trade name: Eslex BM-S, manufactured by Sekisui Chemical Co., Ltd.) and 100 parts by weight of chlorobenzene. The mixture was mixed and treated with glass beads by a paint shake method for 2 hours and dispersed to obtain a coating solution for a charge generation layer. The obtained coating solution for a charge generation layer is applied on an aluminum substrate (20 × 100 × 2 mm, conductive support) by a dip coating method, and dried by heating at 115 ° C. for 10 minutes to form a charge having a thickness of 0.5 μm. A generating layer was formed.

-Formation of S-shaped (non-uniform) charge transport layer- Next, the "block copolymer 1" obtained in "Synthesis Example 4"
Was dissolved in 90 parts by weight of cyclohexanone, and the prepared coating liquid for an S-shaped charge transporting layer was applied on the charge generating layer by a dip coating method.
For 10 minutes to form a 3 μm thick S-shaped charge transport layer. When the S-shaped charge transport layer was observed with a transmission electron microscope using a ruthenic acid staining method, a phase separation structure considered to be a modulation structure was observed. The scale of the phase separation structure was about 0.03 μm, and the volume ratio of the charge transporting phase was about 60%. Furthermore, S
The charge mobility of the charge-transporting polymer having the same structure as the charge-transport block in the cross-shaped (non-uniform) charge-transport layer is 5 V /
Under an electric field strength of μm, it was 6 × 10 ⁻⁵ cm ² / Vs.

-Formation of Uniform Charge Transport Layer, Preparation of Electrophotographic Photoreceptor- Next, a compound 1 having a weight average molecular weight of 80,000 and having a repeating unit represented by the following structural formula 1, which is a polymer charge transport material.
A coating solution for a uniform charge transport layer in which 5 parts by weight was dissolved in 85 parts by weight of chlorobenzene was applied by dip coating on the S-shaped charge transport layer, and was dried by heating at 135 ° C. for 1 hour to form a 20 μm-thick uniform film. A charge transport layer was formed, and an electrophotographic photosensitive member having a layer configuration shown in FIG. 4 was produced.

Structural formula 1

Embedded image

<Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability> -Measurement / Evaluation of Electrophotographic Characteristics / Durability- Electrostatic copying paper test in which the obtained electrophotographic photosensitive member was partially modified. Using an apparatus (Electrostatic Analyzer EPA-8100, manufactured by Kawaguchi Electric Mfg. Co., Ltd.), the electrophotographic characteristics were evaluated under normal temperature and normal humidity (20 ° C., 40% RH) environment. After adjusting the corona discharge voltage and charging the surface of the electrophotographic photosensitive member to -750 V, the halogen lamp light monochromatized to 750 nm through an interference filter is to have a light intensity of 1 μW / cm ^{2 on} the surface of the electrophotographic photosensitive member. And irradiating for 7 seconds, the value of E _50% / E _10% was 2.
2, which is an S-shaped photoinduced potential decay as shown in FIG. The E _50% value is 3 μJ / cm ² and the residual potential is 25.
V.

Further, this is repeated 15000 times,
When the 000 th electrophotographic characteristic evaluation was performed,
An S-shaped photoinduced potential decay as shown in FIG. 2 was obtained, where the value of _50% / E10 _% was 2.3. The E50% value is 3.1.
μJ / cm ² and the residual potential were 28V.

-Measurement / Evaluation of Image Quality / Durability- In the "Production of electrophotographic photosensitive member" of the present example, all the steps were the same except that the conductive support was replaced with an aluminum drum (30 mm diameter). Laser printer (Laser Press 4) using the electrophotographic photoreceptor
105, manufactured by Fuji Xerox Co., Ltd.)
A continuous printing test for 2,000 sheets was performed in an environment of 0 ° C. and 40% RH (A4 horizontal direction). At this time, an ND filter was provided in the optical path of the laser beam in order to obtain an optimal exposure amount. When the image quality of the obtained image was evaluated by visual observation, both the first sample and the print sample after continuous printing of 2,000 sheets were excellent in image quality.

(Example 2) <Preparation of electrophotographic photoreceptor> -Formation of undercoat layer- A zirconium alkoxide compound (trade name: Organix ZC540) was formed on the same aluminum substrate as used in "Example 1". , Manufactured by Matsumoto Pharmaceutical Co., Ltd.) 10 parts by weight,
1 part by weight of a silane compound (trade name: A1110, manufactured by Nippon Unicar), 40 parts by weight of isopropanol, and n
A coating solution for an undercoat layer consisting of 20 parts by weight of butanol was applied by a dip coating method, and then heated and dried at 150 ° C. for 10 minutes to form an undercoat layer having a thickness of 0.1 μm.

-Formation of charge generation layer- In an X-ray diffraction spectrum using CuKα as a radiation source, at least a Bragg angle (2θ ± 0.2) 7.4, 16.
4 parts by weight of chlorogallium phthalocyanine microcrystals having strong diffraction peaks at 6, 2, 5.5 and 28.3 were converted to a vinyl chloride-vinyl acetate copolymer (trade name: UCAR Solution Vinyl Resin VMCH, manufactured by Union Carbide). 2 parts by weight, 67 parts by weight of xylene, and 33 parts by weight of butyl acetate were mixed with glass beads by a paint shake method for 2 hours and dispersed to obtain a coating solution for a charge generation layer. The obtained coating solution for a charge generation layer was applied on the undercoat layer by a dip coating method, and dried by heating at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.3 μm.

-Formation of S-shaped (non-uniform) charge transport layer- S-shaped charge transport having a thickness of 3 μm in the same manner as in "Formation of S-shaped (non-uniform) charge transport layer" in "Example 1". A layer was formed.

—Formation of Uniform Charge Transport Layer— In “Formation of Uniform Charge Transport Layer, Preparation of Electrophotographic Photoreceptor” in “Example 1”, the polymer charge transport material was replaced with the following structural formula having a weight average molecular weight of 120,000. A uniform charge transport layer having a thickness of 20 μm was formed in the same manner as in “Example 1” except that the compound having the repeating unit represented by 2 was used.
An electrophotographic photoreceptor having the layer structure shown in Table 1 was produced.

Structural formula 2

Embedded image

<Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability> Measurement / evaluation was performed in the same manner as “Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability” in “Example 1”.
In the "Measurement / Evaluation of Electrophotographic Characteristics / Durability", in the initial electrophotographic photoreceptor, the photoinduced potential decay characteristics were as follows: residual potential: 15 V, E50 _% value: 1 μJ / cm ² , E50 _% / E _Ten%
In the electrophotographic photoreceptor having an S-shaped value of 2.0 and subjected to 15,000 repetition tests, the photoinduced potential decay characteristics were as follows: residual potential was 20 V, E50 _% value was 1.2 μJ / c.
The m ² and E ₅₀ % / E _10% values were 2.1, and both exhibited S-shaped photoinduced potential decay as shown in FIG. Also,
In "Measurement / Evaluation of Image Quality / Durability",
Both print samples after continuous printing of 0 sheets were excellent in image quality.

Example 3 <Preparation of Electrophotographic Photoreceptor> In “Formation of charge generation layer” in “Example 2”, chlorogallium phthalocyanine microcrystals were used at least in an X-ray diffraction spectrum using CuKα as a radiation source. Bragg angle (2θ ± 0.2) 7.5, 9.9, 12.5, 16.
In place of hydroxygallium phthalocyanine microcrystals having strong diffraction peaks at 3, 18.6, 25.1 and 28.3, 67 parts by weight of xylene as a dispersion solvent and 33 parts by weight of butyl acetate were replaced with 100 parts by weight of monochlorobenzene. In addition, in "Formation of S-shaped (non-uniform) charge transport layer", the thickness of the S-shaped charge transport layer was changed to 24 [mu] m and the step of "Formation of uniform charge transport layer" was not provided. An electrophotographic photoreceptor having the layer configuration shown in FIG. 3 was produced in the same manner as in "Example 2".

<Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability> Measurement / evaluation was performed in the same manner as “Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability” in “Example 1”.
In the "Measurement / Evaluation of Electrophotographic Characteristics / Durability", in the initial electrophotographic photosensitive member, the photoinduced potential decay characteristics were as follows: residual potential was 14 V, E50 _% value was 0.5 μJ / cm ² , E50 _%. /
In the electrophotographic photoreceptor which is an S-shape having an E10 _% value of 2.4 and repeatedly tested 15,000 times, the photoinduced potential decay characteristics are as follows: residual potential is 21 V, E50 _% value is 0.7 μJ / c.
The m ² and E _50% / E _10% values were 2.3, and all exhibited S-shaped photoinduced potential decay as shown in FIG. Also,
In "Measurement / Evaluation of Image Quality / Durability",
Both print samples after continuous printing of 0 sheets were excellent in image quality.

Example 4 <Preparation of Electrophotographic Photoreceptor> -Formation of Charge Generating Layer- A hexachlorocrystalline selenium (12 parts by weight) was mixed with a vinyl chloride-vinyl acetate copolymer resin (trade name: UCAR Solution Vinyl Resin VMCH, Union) 1.8 parts by weight (Carbide Co.) and 100 parts by weight of isobutyl acetate were mixed with a stainless steel bead for 5 hours using a paint shaker and dispersed to obtain a coating liquid for a charge generation layer. The obtained coating solution for a charge generation layer is applied by dip coating on an aluminum substrate similar to that used in "Example 1", and dried by heating at 100 ° C. for 10 minutes to generate a charge having a thickness of 0.15 μm. A layer was formed.

-Formation of S-shaped (non-uniform) charge transport layer- "Formation of S-shaped (non-uniform) charge transport layer" in "Example 1"
In the above, the “block copolymer 1” obtained in “Synthesis Example 4” was replaced with the “block copolymer 2” obtained in “Synthesis Example 6”.
Instead of changing the thickness of the S-shaped charge generation layer to 23 μm, an S-shaped charge transport layer was formed in the same manner as in “Example 1”, and the electrophotographic photosensitive member having the layer configuration shown in FIG. The body was made. When the S-shaped charge transporting layer was observed with a transmission electron microscope using a ruthenic acid staining method, a phase separation structure considered to be a modulation structure was observed. The scale of the phase separation structure was about 0.01 μm, and the volume ratio of the charge transporting phase was about 60%. The charge transporting polymer having the same structure as the charge transporting block has a charge mobility of 5 V / μm
Under the electric field strength of 8 × 10 ⁻⁶ cm ² / Vs.

<Measurement / Evaluation of Electrophotographic Characteristics, Image Quality, and Durability>
In "Evaluation", the exposure wavelength of the halogen lamp light in "Measurement and evaluation of electrophotographic characteristics and durability" was set to 500 n.
m was measured and evaluated in the same manner as in “Example 1” except that the initial potential was changed to m. In the initial electrophotographic photoreceptor, the photoinduced potential decay characteristics were such that the residual potential was 5 V and the E _50% value was 0.1 _% . 8μ
J / cm ² , E _50% / E _10% Value is 2.2 S-shaped,
In the electrophotographic photosensitive member that was repeatedly tested 15,000 times, the photoinduced potential decay characteristics were as follows: residual potential was 10 V, E50 _%
The value was 1.0 μJ / cm ² , and the value of E _50% / E _10% was 2.0, and all exhibited S-shaped photoinduced potential decay as shown in FIG. Further, the "measurement / evaluation of image quality / durability" was performed in the same manner as in "Example 1". As a result, the image quality of both the first sheet and the print sample after continuous printing of 2000 sheets was excellent.

Example 5 <Preparation of Electrophotographic Photoreceptor> “Formation of S-shaped (non-uniform) charge transport layer” in “Example 2”
, An electrophotographic photoreceptor was produced in the same manner as in "Example 2" except that "block copolymer 1" was replaced by "block copolymer 2".

<Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability> Measurement / evaluation was performed in the same manner as “Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability” in “Example 1”.
In the "Measurement / Evaluation of Electrophotographic Characteristics / Durability", in the initial electrophotographic photosensitive member, the photoinduced potential decay characteristics were as follows: residual potential was 15 V, E50 _% value was 1.5 μJ / cm ² , E50 _%. /
In the electrophotographic photoreceptor which is an S-shape having an E10 _% value of 2.1 and repeatedly tested 15,000 times, the photoinduced potential decay characteristics are as follows: the residual potential is 22 V, and the E50 _% value is 1.6 μJ / c.
The m ² and E _50% / E _10% values were 2.2, and all exhibited S-shaped photoinduced potential decay as shown in FIG. Also,
In "Measurement / Evaluation of Image Quality / Durability",
Both print samples after continuous printing of 0 sheets were excellent in image quality.

(Example 6) <Preparation of electrophotographic photosensitive member>"Formation of S-shaped (non-uniform) charge transport layer" in "Example 2"
, An electrophotographic photosensitive member was produced in the same manner as in "Example 2" except that "block copolymer 1" was replaced with "block copolymer 3".

<Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability> Measurement / evaluation was performed in the same manner as “Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability” in “Example 1”.
In "Measurement / Evaluation of Electrophotographic Characteristics and Durability", in the initial electrophotographic photosensitive member, the residual potential was 18 V, the E50 _% value was 1.4 μJ / cm ² , and the E50 _% /
E In the electrophotographic photoreceptor having a _10% value of 1.9 and repeatedly tested 15,000 times, the photoinduced potential decay characteristic is as follows:
Residual potential is 20 V, E _50% value is 1.4 μJ / cm ² , E
_{The 50%} / E10 _% value was 2.0, and all exhibited S-shaped photoinduced potential decay as shown in FIG. In the “measurement / evaluation of image quality / durability”, both the first sample and the print sample after continuous printing of 2,000 sheets were excellent in image quality.

(Example 7) <Preparation of electrophotographic photosensitive member>"Formation of S-shaped (non-uniform) charge transport layer" in "Example 2"
In the above, except that “block copolymer 1” was replaced with “block copolymer 2” and 0.05 part by weight of hexamethylene diisocyanate was further added to the S-shaped (non-uniform) charge transport layer coating solution, An electrophotographic photosensitive member was produced in the same manner as in "Example 2."

<Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability> Measurement / evaluation was performed in the same manner as “Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability” in “Example 1”.
In the "Measurement / Evaluation of Electrophotographic Characteristics / Durability", in the initial electrophotographic photoreceptor, the photoinduced potential decay characteristics were as follows: residual potential was 10 V, E50 _% value was 1.2 μJ / cm ² , E50 _%. /
E In the electrophotographic photoreceptor having a _10% value of 1.9 and repeatedly tested 15,000 times, the photoinduced potential decay characteristic is as follows:
Residual potential is 20 V, E _50% value is 1.5 μJ / cm ² , E
_{The 50%} / E10 _% value was 1.9, and all exhibited an S-shaped photoinduced potential decay as shown in FIG. In the “measurement / evaluation of image quality / durability”, both the first sample and the print sample after continuous printing of 2,000 sheets were excellent in image quality.

Example 8 <Preparation of Electrophotographic Photoreceptor> “Formation of S-shaped (non-uniform) charge transport layer” in “Example 2”
In the above, except that “block copolymer 1” was replaced by “block copolymer 3”, and 0.03 parts by weight of xylene diisocyanate was further added to the coating liquid for the S-shaped (non-uniform) charge transport layer, An electrophotographic photosensitive member was produced in the same manner as in "Example 2".

<Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability> Measurement / evaluation was performed in the same manner as “Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability” in “Example 1”.
In the "Measurement / Evaluation of Electrophotographic Characteristics / Durability", in the initial electrophotographic photosensitive member, the photoinduced potential decay characteristics were as follows: residual potential was 15 V, E50 _% value was 1.5 μJ / cm ² , E50 _%. /
E In the electrophotographic photoreceptor having a _10% value of 1.8 and repeatedly tested 15,000 times, the photoinduced potential decay characteristic is as follows:
Residual potential is 23 V, E _50% value is 1.6 μJ / cm ² , E
_{The 50%} / E10 _% value was 2.2, and all exhibited an S-shaped photoinduced potential decay as shown in FIG. In the “measurement / evaluation of image quality / durability”, both the first sample and the print sample after continuous printing of 2,000 sheets were excellent in image quality.

(Comparative Example 1) <Preparation of Electrophotographic Photoreceptor> In “Preparation of Electrophotographic Photoreceptor” in “Example 2”,
An electrophotographic photosensitive member was manufactured in the same manner as in "Example 2" except that the step of "formation of an S-shaped (non-uniform) charge transport layer" was not provided.

<Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability> Measurement / evaluation was performed in the same manner as “Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability” in “Example 1”.
In "Measurement / Evaluation of Electrophotographic Characteristics and Durability", in the initial electrophotographic photosensitive member, the photoinduced potential decay characteristics were as follows: residual potential was 18 V, E50 _% value was 2.6 μJ / cm ² , E50 _%. /
The E10 _% value was 5.2, indicating a J-shaped photoinduced potential decay as shown in FIG. After the test was repeated 13,000 times, the residual potential and the value of E _50% / E _10% tended to increase. In the electrophotographic photosensitive member subjected to the test repeated 15,000 times, the residual potential increased to 30V. Further, in the "measurement / evaluation of image quality / durability", the print quality was inferior to the examples in terms of reproducibility of fine lines and the like.

Comparative Example 2 <Preparation of Electrophotographic Photoreceptor> In the X-ray diffraction spectrum using CuKα as a radiation source, at least the Bragg angle (2
θ ± 0.2), dichlorotin phthalocyanine crystal 5 having strong diffraction peaks at 8.3, 13.7, and 28.3
Parts by weight were mixed with 10 parts by weight of bisphenol Z type polycarbonate resin (trade name: PC-Z, manufactured by Mitsubishi Gas Chemical Company) and 100 parts by weight of chlorobenzene, and dispersed by treating with stainless beads for 4 hours by a paint shake method. And applying the obtained dispersion to the same aluminum substrate as used in Example 1 by a dip coating method,
Heated and dried at 115 ° C for 60 minutes to a thickness of 23 µm
Was formed.

<Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability> Regarding the obtained single-layer type electrophotographic photoreceptor, "Measurement / Evaluation of Electrophotographic Characteristics / Image Quality / Durability" in "Example 1" When measurement and evaluation were performed in the same manner, in the “measurement and evaluation of electrophotographic characteristics and durability”, in the initial electrophotographic photoreceptor, the photoinduced potential decay characteristics showed a residual potential of 5%.
The V and E _50% values were 2.5 μJ / cm ² and the E _50% / E _10% values were 1.7, indicating an S-shaped photoinduced potential decay as shown in FIG. Further, in the electrophotographic photosensitive member which was repeatedly tested 15,000 times, the residual potential was 15 V, the E _50% value was 2.7 μJ / cm ² , and the E _50% / E _10% value was 1.7.
An S-shaped photoinduced potential decay as shown in FIG. 2 was shown. In "measurement / evaluation of image quality / durability", the print quality of the first sheet was the same, but on the 2,000th sheet, background fogging occurred and reproducibility of fine lines was significantly reduced. .

In the embodiment, since a highly durable block was introduced as the insulating block, the image quality and
It can be seen that the electrophotographic properties are excellent and the durability is also excellent.

[0194]

According to the present invention, an electrophotographic photoreceptor which has a high degree of freedom in selection of physical properties and the like, is easy to produce, has a high yield of a charge transport material at the time of production, and can form a high quality image. , A process cartridge using the same, and an electrophotographic apparatus can be provided.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between an exposure amount and a surface potential in a J-shaped electrophotographic photosensitive member.

FIG. 2 is a graph showing a relationship between an exposure amount and a surface potential in an S-shaped electrophotographic photosensitive member.

FIG. 3 is a schematic enlarged sectional view showing an example of the electrophotographic photosensitive member of the present invention.

FIG. 4 is a schematic enlarged sectional view showing another example of the electrophotographic photosensitive member of the present invention.

FIG. 5 is a schematic enlarged sectional view showing another example of the electrophotographic photosensitive member of the present invention.

FIG. 6 is a schematic enlarged sectional view showing another example of the electrophotographic photosensitive member of the present invention.

FIG. 7 is a schematic configuration diagram illustrating an example of the electrophotographic apparatus of the present invention.

[Explanation of symbols]

1, 1 ', 1 ", 1"': conductive support 2, 2 ', 2 ", 2'": charge generating layer 3, 3 ', 3 ", 3'": non-conductive Uniform charge transport layer (S-shaped charge transport layer) 4, 4 ': uniform charge transport layer 10, 10', 10 ", 10 '": electrophotographic photosensitive member 11: photosensitive drum (electrophotographic photosensitive member) 12: Pre-exposure light source (red LED) 13: Charging scorotron (charging means) 14: Exposure laser optical system (image exposure means) 15: Developing device (developing device) 16: Transfer corotron 17: Blade type cleaning device (Cleaning means) 18: Paper

Claims (4)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive support and at least one photosensitive layer containing a charge transport material formed on the surface thereof, wherein the charge transport material is represented by the following general formula (1). An electrophotographic photoreceptor obtained by subjecting a charge transporting compound having a repeating unit to an insulating compound to block copolymerization and / or graft copolymerization. General formula (1) In the general formula (1), Ar ¹ and Ar ² represent an aryl group. Further, as a whole charge transporting compound having a repeating unit represented by the general formula (1), at least one of the aryl groups represented by Ar ¹ or Ar ² has a reactive group as a substituent. . X ¹ and X ² each independently represent an arylene group, and the arylene group may be substituted. X ³ represents a divalent hydrocarbon group having an aromatic ring structure or a hetero atom-containing hydrocarbon group. L represents a divalent hydrocarbon group or a heteroatom-containing hydrocarbon group. L
May include a branched structure or a ring structure. m represents 0 or 1. 2. The electrophotographic photoconductor according to claim 1, wherein the reactive group is a hydroxymethyl group. 3. An electrophotographic photosensitive member according to claim 1 or 2, and at least one unit selected from the group consisting of a charging unit, a developing unit, a charge removing unit, and a cleaning unit. , A process cartridge that can be attached to and detached from electrophotographic equipment. 4. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 1 or 2, or the process cartridge according to claim 3.