JP2011186302A - Electrophotographic photoreceptor and image forming apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable organic photoconductive material which is free from problems such as partial crystallization during film formation and has high charge potential, high sensitivity, satisfactory photoresponse, and excellent durability even when used under a low temperature environment or in high-speed process and does not deteriorate in these properties even by light exposure; and to provide an electrophotographic photoreceptor and an image forming apparatus each employing the material. <P>SOLUTION: In the photoreceptor, a laminate type photosensitive layer or a single-layer type photosensitive layer is formed on a conductive support 1, and a charge transport layer 3 or the single-layer type photosensitive layer contains a charge transport material which has a benzofuran in a skeleton, butadiene in a linking group, and arylamine, heteroaryl, benzothiophene, indole, and thiophene in a substituent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic photoconductive material, an electrophotographic photoreceptor using the same, and an image forming apparatus.

  In recent years, organic photoconductive materials have been widely researched and developed and used not only for electrophotographic photoreceptors (hereinafter also simply referred to as “photoreceptors”), but also for electrostatic recording elements, sensor materials, or organic electroluminescent (Electro Luminescent (abbreviation: EL) devices have begun to be applied.

  In addition, electrophotographic photoreceptors using organic photoconductive materials are used not only in the field of copying machines, but also in fields such as printing plate materials, slide films, and microfilms in which photographic technology has been used. It is also applied to a high-speed printer using a laser, a light emitting diode (abbreviation: LED), or a cathode ray tube (abbreviation: CRT) as a light source.

In addition, an organic photoreceptor using an organic photoconductive material has good film-forming properties of the photosensitive layer, excellent flexibility, light weight, good transparency, and a wide range by a suitable sensitizing method. Since it has the advantage that a photoconductor showing good sensitivity with respect to a wavelength region can be easily designed, it has been gradually developed as a mainstay of electrophotographic photoconductors.
Therefore, it is difficult to form a conventional photosensitive layer, and there are problems such as poor plasticity and high manufacturing cost. In general, the photosensitive layer is highly toxic, and instead of an inorganic photoconductive material that is severely restricted in manufacturing and handling. The demands on organic photoconductive materials and electrophotographic photoreceptors using the same are becoming sophisticated and broad.

  Early organic photoreceptors had drawbacks in sensitivity and durability, but these drawbacks were due to the development of a function-separated electrophotographic photoreceptor in which the charge generation function and the charge transport function were assigned to separate substances. Significant improvement.

  The function-separated type photoconductor has advantages that the material selection range of the charge generation material responsible for the charge generation function and the charge transport material responsible for the charge transport function is wide, and an electrophotographic photoconductor having arbitrary characteristics can be produced relatively easily. Also have.

  Examples of the charge generating material used in such a function-separated type photoreceptor include various types such as phthalocyanine pigments, squarylium dyes, azo pigments, perylene pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes and pyrylium salt dyes. Substances have been studied, and various materials having high light resistance and high charge generation ability have been proposed.

  On the other hand, examples of the charge transport material include pyrazoline compounds (see, for example, Patent Document 1), hydrazone compounds (see, for example, Patent Document 2, Patent Document 3, and Patent Document 4), triphenylamine compounds (for example, Patent Document 5 and Various compounds such as Patent Document 6) and stilbene compounds (see, for example, Patent Document 7 and Patent Document 8) are known. Recently, pyrene derivatives, naphthalene derivatives and terphenyl derivatives (see, for example, Patent Document 9) having a condensed polycyclic hydrocarbon system in the central mother nucleus have been developed.

For charge transport materials:
(1) being stable to light and heat;
(2) being stable against ozone, nitrogen oxide (NOx), nitric acid, etc. generated by corona discharge when charging the surface of the photoreceptor;
(3) having a high charge transport capability;
(4) High compatibility with organic solvents and binders,
(5) It must be easy and inexpensive to manufacture.

However, although the aforementioned charge transport materials meet some of these requirements, they have not yet met all at a high level.
In addition, among the above requirements, it is particularly required to have a high charge transport capability. For example, when a charge transport layer formed by dispersing a charge transport material together with a binder resin is the surface layer of the photoreceptor, the charge transport material is required to have a high charge transport capability in order to ensure sufficient photoresponsiveness. It is done.

  When the photoconductor is mounted and used in a copying machine or a laser beam printer, a part of the surface layer of the photoconductor is forced to be scraped off by a contact member such as a cleaning blade or a charging roller. In order to enhance the durability of copying machines and laser beam printers, a surface layer that is strong against the contact members, that is, a surface layer with high printing durability that is hardly scraped off by the contact members is required.

Therefore, if the content of the binder resin in the charge transport layer, which is the surface layer, is increased in order to strengthen the surface layer and improve the durability, the photoresponsiveness decreases.
This is because the charge transport capacity of the charge transport material is low, so the charge transport material in the charge transport layer is diluted with an increase in the binder resin content, and the charge transport capacity of the charge transport layer is further reduced, resulting in a light response. It will be worse.

If the photoresponsiveness is poor, the residual potential rises, and the surface potential of the photoconductor is repeatedly attenuated, so the surface charge of the portion to be erased by exposure is sufficiently erased. This will cause problems such as image quality deterioration at an early stage.
Therefore, in order to ensure sufficient photoresponsiveness, the charge transport material is required to have a high charge transport capability.

  In recent years, electrophotographic apparatuses such as digital copying machines and printers have been miniaturized and speeded up, and there is a demand for higher sensitivity corresponding to higher speeds as photoconductor characteristics. Ability is required. In a high-speed process, since the time from exposure to development is short, a photoconductor with good photoresponsiveness is required. As described above, since the photoresponsiveness depends on the charge transporting ability of the charge transporting substance, a charge transporting substance having a higher charge transporting ability is required from this point.

  Various compounds having higher charge mobility than the above-described charge transport materials have been proposed as charge transport materials that satisfy such requirements (for example, Patent Document 10, Patent Document 11, Patent Document 12, and Patent Document 13). reference).

Japanese Patent Publication No.52-4188 JP-A-54-150128 Japanese Patent Publication No.55-42380 JP-A-55-52063 Japanese Patent Publication No.58-32372 JP-A-2-190862 JP 54-151955 A JP 58-198043 A JP 7-48324 A Japanese Patent Laid-Open No. 2-51162 Japanese Patent Laid-Open No. 6-43674 Japanese Patent Laid-Open No. 10-69107 JP-A-10-239875

However, the performance of the photoreceptor using the enamine compound described in Patent Document 10, Patent Document 11 or Patent Document 12 is not sufficient, and the compound described in Patent Document 13 introduces a partial structure of bisbutadiene and exhibits symmetry. Due to the good structure, the compatibility between the charge transport material and the binder resin is extremely poor, and adverse effects such as partial crystallization occur during film formation.
This measure can be dealt with to some extent by changing the structural unit from a large structural unit such as an aryl group to a methyl group of the smallest structural unit. However, in terms of electrical properties (especially hole mobility), the substituent is alkyl. Aryl groups are preferred over groups and are a problem that must be improved.

  As for the characteristics of the photoreceptor, the sensitivity does not decrease even when used in a low temperature environment, and it is required that the change in characteristics is small and the reliability is high under various environments. No real charge transport material has been obtained.

  The object of the present invention is to produce a high charging potential, high sensitivity and sufficient photoresponsiveness without causing adverse effects such as partial crystallization during film formation. An organic photoconductive material capable of realizing a highly reliable electrophotographic photosensitive member that does not deteriorate in properties even when used in a high-speed process, and that does not deteriorate even when exposed to light. It is an object to provide an electrophotographic photosensitive member and an image forming apparatus used.

  As a result of repeated studies, the inventors of the present invention have excellent compatibility with the binder resin because the charge transport layer or the single layer type photosensitive layer of the laminated type photosensitive layer contains a specific asymmetric butadiene compound, High charging potential, high sensitivity, sufficient photoresponsiveness, excellent durability, no deterioration in properties when used in low-temperature environments or high-speed processes, and exposure to light The present inventors have found that a highly reliable electrophotographic photosensitive member that does not deteriorate the characteristics can be provided, and have completed the present invention.

（式中、Ａｒ₁およびＡｒ₂は置換基を含んでもよいアリール基を示し、Ａｒ₃およびＡｒ₄は水素原子または置換基を有していてもよいアリールもしくはヘテロアリール基を示す）
で示される非対称ブタジエン化合物を含有していることを特徴とする電子写真感光体が提供される。 However, according to the present invention, a layered photosensitive layer in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are laminated in this order, or a single layer containing a charge generation material and a charge transport material. A layer-type photosensitive layer is formed on a conductive support, and the charge transport layer or the single-layer type photosensitive layer has the following general formula (I) as a charge transport material:

(In the formula, Ar ₁ and Ar ₂ represent an aryl group which may contain a substituent, Ar ₃ and Ar ₄ represent a hydrogen atom or an aryl or heteroaryl group which may have a substituent)
An electrophotographic photosensitive member comprising the asymmetric butadiene compound represented by the formula:

  According to the invention, the charge transport layer or the single-layer type photosensitive layer further contains a binder resin, and in the charge transport layer or the single-layer type photosensitive layer, the charge transport material (A) and the above-mentioned The electrophotographic photosensitive member is provided in which the ratio A / B to the binder resin (B) is 10/12 to 10/30 by mass ratio.

  According to the invention, the charge generation layer or the single-layer type photosensitive layer has a Bragg angle (2θ ± 0.2 °) in Cu-Kα characteristic X-ray diffraction (wavelength: 1.54Å) of at least 27. There is provided the above-mentioned electrophotographic photosensitive member containing oxotitanium phthalocyanine having a distinct diffraction peak at 2 ° as a charge generating material.

  Further, according to the present invention, there is provided the electrophotographic photosensitive member having an intermediate layer between the laminated photosensitive layer or the single-layer type photosensitive layer and the conductive support.

According to the present invention, there is provided an image forming apparatus comprising the electrophotographic photosensitive member.
Furthermore, according to the present invention, there is provided the image forming apparatus in which the image forming apparatus forms an image using a reversal development process.

  According to the present invention, the organic photoconductive material is an asymmetric butadiene compound represented by the general formula (I) and has a high charge mobility. In addition, the asymmetric butadiene has excellent compatibility with the binder resin by incorporating different partial structures (benzofuran structure, phenyl structure) into the same carbon at the end of the butadienyl group in order to break the symmetry of the molecular structure. The charge transport material of the present invention having a high charge mobility that does not cause adverse effects such as partial crystallization during film formation can be used as the organic photoconductive material.

By using the asymmetric butadiene compound of the general formula (I) as a charge transport material, it has a high charging potential, high sensitivity, sufficient photoresponsiveness, excellent durability, and used in a low temperature environment or in a high-speed process. Even in such a case, it is possible to realize a highly reliable electrophotographic photosensitive member in which those characteristics are not deteriorated and those characteristics are not deteriorated by light exposure.
In addition, if the organic photoconductive material is used for a sensor material, an EL element, an electrostatic recording element, or the like, a device having excellent responsiveness can be provided.

  In addition, in an electrophotographic photoreceptor comprising a conductive support made of a conductive material according to the present invention, and a photosensitive layer provided on the conductive support and containing a charge generation material and a charge transport material, The charge transport material includes the organic photoconductive material.

  According to the present invention, the photosensitive layer contains an organic photoconductive material having a high charge mobility represented by the general formula (1) as a charge transport material, so that the charging potential is high, the sensitivity is high, It is possible to obtain an electrophotographic photosensitive member that exhibits sufficient photoresponsiveness, is excellent in durability, and does not deteriorate when used in a low temperature environment or in a high-speed process. Further, since a high charge transport capability can be realized without containing polysilane in the photosensitive layer, a highly reliable electrophotographic photosensitive member whose characteristics are not deteriorated by light exposure can be obtained.

The electrophotographic photosensitive layer according to the present invention has a clear diffraction peak at a Bragg angle (2θ ± 0.2 °) of at least 27.2 ° in Cu-Kα characteristic X-ray diffraction (wavelength: 1.54 mm). By containing phthalocyanine as a charge generation material, it has high charge generation efficiency and charge injection efficiency.
The charge generation material generates a large amount of charge by absorbing light, and efficiently injects the generated charge into the charge transport material without accumulating inside the charge generation material.
As described above, the photosensitive layer contains a charge transport material having a high charge mobility represented by the general formula (1) as an organic photoconductive material. Therefore, the charge generated in the charge generation material by light absorption is efficiently injected into the charge transport material and smoothly transported, so that an electrophotographic photosensitive member with high sensitivity and high resolution can be obtained.

  According to one embodiment of the present invention, the photosensitive layer has a laminated structure of a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material. As described above, by assigning the charge generation function and the charge transport function to different layers, it is possible to select the optimum materials for the charge generation function and the charge transport function. Thereby, it is possible to obtain an electrophotographic photosensitive member having higher durability and higher durability with increased stability during repeated use.

According to the present invention, a conventionally known charge transport material is used by using the ratio A / B of the charge transport material (A) and the binder resin (B) contained in the charge transport layer at a ratio of 10/12 to 10/30. Even if a binder resin is added at a higher ratio than when using, photoresponsiveness can be maintained.
Therefore, the printing durability of the charge transport layer can be improved and the durability of the electrophotographic photosensitive member can be improved without reducing the photoresponsiveness.

According to the present invention, by providing an intermediate layer between the conductive support and the photosensitive layer, injection of charges from the conductive support to the photosensitive layer can be prevented, and the chargeability of the photosensitive layer can be prevented. Therefore, it is possible to prevent the surface charge from being reduced except for the portion to be erased by exposure, and to prevent the occurrence of defects such as fogging on the image. Further, since a uniform surface can be obtained by coating defects on the surface of the conductive support, the film formability of the photosensitive layer can be improved.
Furthermore, by providing the intermediate layer, peeling of the photosensitive layer from the conductive support can be suppressed, and the adhesion between the conductive support and the photosensitive layer can be improved.
The present invention is also an image forming apparatus comprising the electrophotographic photosensitive member.

  The electrophotosensitive material according to the present invention is an electron having a high charging potential, high sensitivity, sufficient photoresponsiveness, excellent durability, and characteristics that do not deteriorate even when used in a low temperature environment or in a high-speed process. Since the photographic photosensitive member is provided, it is possible to obtain a highly reliable image forming apparatus capable of providing a high-quality image under various environments. In addition, since the characteristics of the electrophotographic photosensitive member are not deteriorated by light exposure, it is possible to prevent deterioration of image quality due to exposure of the photosensitive member to light during maintenance or the like, and to improve the reliability of the image forming apparatus. Can do.

It is a schematic sectional drawing which simplifies and shows the structure of the electrophotographic photoreceptor which is an example of this embodiment. It is a schematic sectional drawing which simplifies and shows the structure of the electrophotographic photoreceptor which is another example of this embodiment. It is a schematic sectional drawing which simplifies and shows the structure of the electrophotographic photoreceptor which is another example of this embodiment. 1 is a configuration diagram illustrating a simplified configuration of an image forming apparatus including an electrophotographic photosensitive member according to the present invention.

（式中、Ａｒ₁およびＡｒ₂は置換基を含んでもよいアリール基を示し、Ａｒ₃およびＡｒ₄は水素原子または置換基を有していてもよいアリールもしくはヘテロアリール基を示す）
で示される非対称ブタジエン化合物を含むことを特徴とする。 The photosensitive layer according to the present invention is a laminated photosensitive layer in which a charge generation layer containing a charge generation material and a charge transport layer containing a charge transport material are laminated in this order, or a single layer containing a charge generation material and a charge transport material Type photosensitive layer is formed on a conductive support, and the charge transport layer or the single layer type photosensitive layer is used as a charge transport material, an organic photoconductive material, and the following general formula (1):

(In the formula, Ar ₁ and Ar ₂ represent an aryl group which may contain a substituent, Ar ₃ and Ar ₄ represent a hydrogen atom or an aryl or heteroaryl group which may have a substituent)
It contains the asymmetric butadiene compound shown by these.

In the general formula (I), specific examples of Ar ₁ and Ar ₂ which may have a substituent include phenyl, tolyl, xylyl, methoxyphenyl, methoxytolyl, t-butylphenyl, naphthyl and biphenylyl. An aryl group can be mentioned.

In the general formula (1), Ar ₃ and Ar ₄ are selected from a hydrogen atom or an aryl, heteroaryl, aralkyl or alkyl group which may have a substituent. However, Ar ₃ and Ar ₄ are not both hydrogen atoms.

Specific examples of Ar ₃ and Ar ₄ which may have the above-described substituent include, except for a hydrogen atom, phenyl, tolyl, methoxyphenyl, naphthyl, pyrenyl, biphenylyl, phenoxyphenyl, p- (phenylthio) phenyl, and aryl groups such as p-styrylphenyl; heteroaryl groups such as furyl, thienyl, trimethylthienyl, thiazolyl, benzofuryl, benzothiophenyl, N-methylindolyl, benzothiazolyl, benzoxazolyl and N-ethylcarbazolyl; benzyl , Aralkyl groups such as p-methoxybenzyl and 1-naphthylmethyl: and alkyls such as methyl, ethyl, trifluoromethyl, fluoromethyl, isopropyl, t-butyl, cyclohexyl, cyclopentyl and 2-thienylmethyl The group can be mentioned.

で表される基であり、 The compound of specific formula (I), the general formula (I), wherein the Ar ₁ and Ar _2, independently of one another, the following formula:

A group represented by

で表される基であるが、但しＡｒ₃およびＡｒ₄が同時に水素原子とはならない一般式（Ｉ）の化合物が挙げられる。 Ar ₃ and Ar ₄ each independently represent a hydrogen atom, or the following formula:

And a compound of the general formula (I) in which Ar ₃ and Ar ₄ do not simultaneously become hydrogen atoms.

で表される基であり、 As a more specific compound of the general formula (I), in the general formula (I), Ar ₁ is represented by the following formula:

A group represented by

で表される基であり、 The Ar ₂ is represented by the following formula:

A group represented by

で表される基であり、そして The Ar ₃ is represented by the following formula:

And a group represented by

で表される基である一般式（Ｉ）の化合物が挙げられる。 Ar ₄ represents a hydrogen atom or the following formula:

The compound of general formula (I) which is group represented by these is mentioned.

で表される基であり、 More specifically, in the general formula (I), the Ar ₁ is represented by the following formula:

A group represented by

で表される基であり、 The Ar ₂ is represented by the following formula:

A group represented by

で表される基であり、そして
前記Ａｒ₄が、水素原子または次の式：

で表される基である一般式（Ｉ）の化合物が挙げられる。 The Ar ₃ is represented by the following formula:

And Ar ₄ is a hydrogen atom or the following formula:

The compound of general formula (I) which is group represented by these is mentioned.

  Since the organic photoconductive material of the present invention is an asymmetric butadiene compound represented by the general formula (1), it has a high charge mobility. By using the organic photoconductive material of the present invention having such a high charge mobility as a charge transport material, it has a high charging potential, high sensitivity, sufficient photoresponsiveness, excellent durability, low temperature When used in an environment or in a high-speed process, it is possible to realize a highly reliable electrophotographic photosensitive member whose characteristics do not deteriorate even when exposed to light. In addition, if the organic photoconductive material is used for a sensor material, an EL element, an electrostatic recording element, or the like, a device having excellent responsiveness can be provided.

Among the organic photoconductive materials represented by the general formula (I), particularly excellent compounds from the viewpoint of characteristics, cost, and productivity include Ar ₁ , Ar _2, and Ar ₃ having a phenyl group or a substituent. And a group in which Ar ₄ is a hydrogen atom, a phenyl group or a phenyl group having a substituent.

で示される４−ブロモ−α−クロロアセトフェノンと、下記構造式（ＩＩＩ）： The asymmetric butadiene compound represented by the general formula (I) which is the organic photoconductive material of the present invention can be produced, for example, as follows.
First, the following structural formula (II):

4-bromo-α-chloroacetophenone represented by the following structural formula (III):

で示される５−ブロモサリチルアルデヒドとを縮合させ分子間エーテルを形成後、分子内アルドール縮合反応を行うことで、下記構造式（ＩＶ）：

で示されるケトン中間体（Ａ）を製造する。

Is then condensed with 5-bromosalicylaldehyde to form an intermolecular ether, followed by an intramolecular aldol condensation reaction, whereby the following structural formula (IV):

A ketone intermediate (A) represented by

で示される２級アリールアミン誘導体とパラジウムを触媒とするアリールアミノ化反応を１：２の等量比にて行うことにより、下記構造式（ＶＩ）： Next, with respect to the ketone intermediate (A) represented by the structural formula (IV), the following general formula (V):

An arylamination reaction using a secondary arylamine derivative represented by formula (II) and palladium as a catalyst at an equivalent ratio of 1: 2 results in the following structural formula (VI):

で示されるケトン中間体（Ｂ）を合成する。
次に、前記一般式（ＶＩ）で示されるケトン中間体（Ｂ）に対して、下記一般式（ＶＩＩ）：

A ketone intermediate (B) shown in FIG.
Next, with respect to the ketone intermediate (B) represented by the general formula (VI), the following general formula (VII):

（式中、Ｘはハロゲン原子を意味する）
で示されるアリルハライド誘導体を金属マグネシウムと処理することで得られるグリニヤール試薬とを反応させることにより、前記一般式（Ｉ）：

(In the formula, X means a halogen atom)
By reacting the allyl halide derivative represented by the following formula (I):

（式中、Ａｒ₁およびＡｒ₂は置換基を含んでもよいアリール基を示し、Ａｒ₃およびＡｒ₄は水素原子または置換基を有していてもよいアリールもしくはヘテロアリール基を示す）
で示される非対称ブタジエン化合物を製造することができる。

(In the formula, Ar ₁ and Ar ₂ represent an aryl group which may contain a substituent, Ar ₃ and Ar ₄ represent a hydrogen atom or an aryl or heteroaryl group which may have a substituent)
Can be produced.

Specific examples of the organic photoconductive material of the present invention represented by the general formula (I) include, for example, exemplified compounds having each group shown in the following table. However, the organic photoconductive material of the present invention is not limited by the following exemplary compounds.
Each group shown in Table 1 below corresponds to each group of the general formula (I), and the substituents Ar ₁ and Ar ₂ or Ar ₃ and Ar ₄ in the general formula (I) are It is understood that they are not fixed and can be interchanged.

で示される非対称ブタジエン化合物である。 For example, in the above general formula (I), Ar ₁ is a tolyl group, Ar ₂ is a xylyl group, Ar ₃ is a phenyl group, and Ar ₄ is a hydrogen atom. The following compound (1):

Is an asymmetric butadiene compound.

  An electrophotographic photoreceptor according to the present invention (hereinafter also simply referred to as “photoreceptor”) uses the organic photoconductive material of the present invention represented by the above general formula (I) as a charge transport material. There are various embodiments. Hereinafter, it will be described in detail with reference to the drawings.

Multilayer Electrophotographic Photoreceptor FIG. 1 is a schematic cross-sectional view showing a simplified structure of an electrophotographic photoreceptor, which is an example of an electrophotographic photoreceptor according to the present invention. In the electrophotographic photosensitive member in FIG. 1, a charge generation layer 5 containing a charge generation material 2, a charge transport material 3 and a charge transport material 3 are bound on a sheet-like conductive support 1 made of a conductive material. A charge transfer layer 6 containing a binder resin to be laminated is a multilayer electrophotographic photosensitive member having a photosensitive layer 4 having a laminated structure in which the conductive support 1 is laminated upward in this order.
In FIG. 1, the charge generating material 2 and the charge transporting material 3 are emphasized and depicted, but in actuality, each layer is configured or uniformly dispersed in components such as a binder resin.

The charge transport layer 6 contains, as the charge transport material 3, an asymmetric butadiene compound having a high charge mobility represented by the general formula (I), which is the organic photoconductive material of the present invention.
Therefore, an electrophotographic photosensitive member having a high charging potential, high sensitivity, sufficient photoresponsiveness, excellent durability, and a property that does not deteriorate even when used in a low temperature environment or a high-speed process is obtained. Can do. Moreover, since a high charge transport capability can be realized without containing polysilane in the photosensitive layer 4, it is possible to obtain a highly reliable electrophotographic photosensitive member whose characteristics are not deteriorated by light exposure.

Further, as described above, the photosensitive layer 4 has a laminated structure of the charge generation layer 5 containing the charge generation material 2 and the charge transport layer 6 containing the charge transport material 3.
In this way, by assigning the charge generation function and the charge transport function to separate layers, it becomes possible to select the most suitable material for each of the charge generation function and the charge transport function. It is possible to obtain an electrophotographic photosensitive member having high durability with increased stability during repeated use.

Conductive Support As the conductive material constituting the conductive support 1, for example, a metal material such as aluminum, aluminum alloy, copper, zinc, stainless steel, and titanium can be used.
Without being limited to these metal materials, polymer materials such as polyethylene terephthalate, nylon and polystyrene, those obtained by laminating metal foil on the surface of hard paper or glass, those obtained by vapor deposition of metal materials, or conductivity A material obtained by depositing or coating a layer of a conductive compound such as a polymer, tin oxide, or indium oxide can also be used.
The shape of the conductive support 1 is a sheet shape in the electrophotographic photosensitive member in FIG. 1, but is not limited thereto, and may be a cylindrical shape, a columnar shape, an endless belt shape, or the like.

If necessary, the surface of the conductive support 1 may be subjected to an anodized film treatment, surface treatment with chemicals or hot water, coloring treatment, or surface roughening within a range that does not affect the image quality. You may perform an irregular reflection process.
In an electrophotographic process using a laser as an exposure light source, the wavelength of the laser beam is uniform, so that the incident laser beam and the light reflected in the electrophotographic photosensitive member cause interference, and interference fringes due to this interference appear on the image. May appear and cause image defects. By performing the above-described treatment on the surface of the conductive support 1, image defects due to interference of laser light having the same wavelength can be prevented.

Charge Generation Layer The charge generation layer 5 contains a charge generation material 2 that generates charges by absorbing light as a main component.

Charge generation materials Effective materials for the charge generation material 2 include azo pigments such as monoazo pigments, bisazo pigments and trisazo pigments; indigo pigments such as indigo and thioindigo; and perylenes such as peryleneimide and perylene anhydride. Pigments; polycyclic quinone pigments such as anthraquinone and pyrenequinone; phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine; squarylium dyes; pyrylium salts and thiopyrylium salts; triphenylmethane dyes; Materials etc. can be mentioned.
These charge generation materials are used alone or in combination of two or more.

Of these charge generation materials, oxotitanium phthalocyanine is preferably used.
Since oxotitanium phthalocyanine is a charge generation material having high charge generation efficiency and charge injection efficiency, it generates a large amount of charge by absorbing light, and the generated charge does not accumulate inside the charge. Efficient injection into the transport material 3 is possible.
As described above, the charge transport material 3 is made of an organic photoconductive material having a high charge mobility represented by the general formula (I).
Therefore, according to the present invention, by using the charge transport material represented by the general formula (I) as the charge transport material, the charge generated in the charge generation material 2 by light absorption is efficiently transferred to the charge transport material 3. Since it is injected and transported smoothly, an electrophotographic photosensitive member with high sensitivity and high resolution can be obtained.

  The charge generation material 2 includes triphenylmethane dyes typified by methyl violet, crystal violet, knight blue and Victoria blue; acridine dyes typified by erythrosine, rhodamine B, rhodamine 3R, acridine orange and frappeosin; methylene blue and Thiazine dyes typified by methylene green, etc .; oxazine dyes typified by capri blue and meldra blue, etc .; cyanine dyes; styryl dyes; may be used in combination with sensitizing dyes such as pyrylium salt dyes or thiopyrylium salt dyes Good.

Binder resin for charge generation layer For example, polyester resin, polystyrene resin, polyurethane resin, phenol resin, alkyd resin, melamine resin, epoxy resin, silicone resin, acrylic resin, methacrylic resin, polycarbonate resin, polyarylate resin, phenoxy One or more selected from the group consisting of resins, resins such as polyvinyl butyral resin and polyvinyl formal resin, and copolymer resins containing two or more of the repeating units constituting these resins. Are mixed and used.

Specific examples of the copolymer resin include insulating resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, and acrylonitrile-styrene copolymer resin. be able to.
The binder resin is not limited to these, and a commonly used resin can be used as the binder resin.

Method for forming charge generation layer Charge generation layer 5 can be formed by vacuum deposition of charge generation material 2 on conductive support 1 or charge generation layer obtained by dispersing charge generation material 2 in a solvent. For example, there is a method of applying the coating liquid on the conductive support 1. Among these, the charge generating material 2 is dispersed by a conventionally known method in a binder resin solution obtained by mixing a binder resin, which is a binder, in a solvent, and the obtained coating solution is used as a conductive support 1. The method of applying on top is preferred. Hereinafter, this method will be described.

Examples of the solvent for the charge generation layer coating solution include halogenated hydrocarbons such as dichloromethane and dichloroethane; ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; tetrahydrofuran (THF) and dioxane and the like Ethers; alkyl ethers of ethylene glycol such as 1,2-dimethoxyethane; aromatic hydrocarbons such as benzene, toluene and xylene; or aprotic such as N, N-dimethylformamide and N, N-dimethylacetamide A polar solvent or the like is used. Moreover, the mixed solvent which mixed 2 or more types of these solvents can also be used.

The mixing ratio of the charge generation layer coating solution charge generation material 2 and the binder resin is preferably such that the ratio of the charge generation material 2 is in the range of 10% by mass to 99% by mass.
When the ratio of the charge generation material 2 is less than 10% by mass, the sensitivity of the charge generation layer decreases.
If the ratio of the charge generation material 2 exceeds 99% by mass, not only the film strength of the charge generation layer 5 is decreased, but also the dispersibility of the charge generation material 2 is decreased and coarse particles are increased. Since the surface charge other than that to be reduced is reduced, image defects, particularly the fogging of images called black spots, in which toner adheres to a white background and minute black spots are formed, increase.
Therefore, it was found that the blending ratio of the charge generation material to the binder resin is preferably 10% by mass to 99% by mass.

Prior to dispersing the charge generation material 2 in the binder resin solution, the charge generation material 2 may be pulverized in advance by a pulverizer. Examples of the pulverizer used for the pulverization treatment include a ball mill, a sand mill, an attritor, a vibration mill, and an ultrasonic disperser.
Examples of the disperser used when the charge generating material 2 is dispersed in the binder resin solution include a paint shaker, a ball mill, and a sand mill. As a dispersion condition at this time, an appropriate condition is selected so that impurities are not mixed due to wear of a container and a member constituting the disperser.

Examples of the coating method of the coating solution for the charge generation layer obtained by dispersing the charge generation material 2 in the binder resin solution include a spray method, a bar coating method, a roll coating method, a blade method, a ring method, and a dip coating method. be able to. Among these application methods, an optimum method can be selected in consideration of the physical properties and productivity of the application.
In particular, the dip coating method is a method in which a layer is formed on the conductive support 1 by immersing the conductive support 1 in a coating tank filled with a coating solution and then pulling it up at a constant speed or a sequentially changing speed. Since it is relatively simple and excellent in terms of productivity and cost, it is widely used in the production of electrophotographic photosensitive members. In addition, you may provide the coating liquid dispersion | distribution apparatus represented by the ultrasonic generator in the apparatus used for the dip coating method in order to stabilize the dispersibility of a coating liquid.

The film thickness of the charge generation layer 5 is preferably 0.05 μm or more and 5 μm or less, more preferably 0.1 μm or more and 1 μm or less.
If the thickness of the charge generation layer 5 is less than 0.05 μm, the light absorption efficiency is lowered and the sensitivity is lowered. If the film thickness of the charge generation layer 5 exceeds 5 μm, the charge transfer inside the charge generation layer becomes a rate-limiting step in the process of erasing the charge on the surface of the photoreceptor, and the sensitivity decreases.
Therefore, it was found that the preferred film thickness of the charge generation layer is 0.05 μm or more and 5 μm or less.

The charge transport layer 6 comprises a charge transport material 3 as an organic photoconductive material of the present invention represented by the general formula (I) having the ability to accept and transport charges generated by the charge generation material 2 as a binder. It is obtained by including in the resin.
Charge Transport Material The charge transport material represented by the general formula (I) is a single compound selected from the group consisting of the compounds (1) to (40) shown in Table 1 above or a mixture of two or more. It is preferred to use.

The charge transport material represented by the general formula (I) may be used by being mixed with other charge transport materials.
Examples of the other charge transport materials include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds. , Polycyclic aromatic compounds, indole derivatives, pyrazoline derivatives, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, triarylmethane derivatives, phenylenediamine derivatives, Examples thereof include stilbene derivatives and benzidine derivatives.
Also included are polymers having groups derived from these compounds in the main chain or side chain, such as poly-N-vinylcarbazole, poly-1-vinylpyrene and poly-9-vinylanthracene.

  However, in order to achieve a particularly high charge transport capability, the total amount of the charge transport material 3 is preferably the organic photoconductive material of the present invention represented by the general formula (I).

Binder resin for charge transport layer The binder resin used for the charge transport layer 6 is selected from those having excellent compatibility with the charge transport material 3. Specific examples include vinyl polymer resins such as polymethyl methacrylate resin, polystyrene resin and polyvinyl chloride resin, and copolymer resins thereof; polycarbonate resin, polyester resin, polyester carbonate resin, polysulfone resin, phenoxy resin, epoxy resin. And resins such as silicone resin, polyarylate resin, polyamide resin, polyether resin, polyurethane resin, polyacrylamide resin, and phenol resin. Moreover, you may use the thermosetting resin which bridge | crosslinked these resin partially.

These resins may be used alone or in combination of two or more.
Among the above-mentioned resins, polystyrene resin, polycarbonate resin, polyarylate resin or polyphenylene oxide has a volume resistance of 10 ¹³ Ω or more and excellent electrical insulation, and also has excellent film properties and potential characteristics. Therefore, it is particularly preferable to use these for the binder resin.

As described above, since the charge transport material 3 includes the organic photoconductive material of the present invention having a high charge mobility represented by the general formula (I), the charge transport material 3 (A), the binder resin (B), Even if the ratio A / B is 10/12 to 10/30 and a binder resin is added at a higher ratio than when a conventionally known charge transport material is used, the photoresponsiveness can be maintained.
Therefore, the printing durability of the charge transport layer 6 can be improved and the durability of the electrophotographic photosensitive member can be improved without reducing the photoresponsiveness.

When the ratio A / B is less than 10/30 and the ratio of the binder resin is high, the viscosity of the coating liquid increases when the charge transport layer 6 is formed by the dip coating method. Sexually worsen.
Further, when the amount of the solvent in the coating solution is increased in order to suppress the increase in the viscosity of the coating solution, a brushing phenomenon occurs, and the formed charge transport layer 6 becomes cloudy. Further, when the ratio A / B exceeds 10/12 and the ratio of the binder resin 17 becomes low, the printing durability becomes lower than when the ratio of the binder resin is high, and the wear amount of the photosensitive layer increases.

  Therefore, the ratio A / B between the charge transport material 3 (A) and the binder resin (B) is generally about 10/12 in terms of mass ratio. 10/12 to 10/30.

Additives for charge transport layer Additives such as plasticizers or leveling agents may be added to the charge transport layer 6 as necessary in order to improve film formability, flexibility and surface smoothness. . Examples of the plasticizer include dibasic acid esters, fatty acid esters, phosphate esters, phthalate esters, chlorinated paraffins, and epoxy type plasticizers. Examples of the leveling agent include a silicone leveling agent.

The charge transport layer 6 may be added with fine particles of an inorganic compound or an organic compound in order to enhance mechanical strength and improve electrical characteristics.
Furthermore, you may add various additives, such as antioxidant and a sensitizer, to the electric charge transport layer 6 as needed. As a result, the potential characteristics are improved, the stability as a coating solution is increased, fatigue deterioration when the photoreceptor is repeatedly used can be reduced, and durability can be improved.

As the antioxidant, a hindered phenol derivative or a hindered amine derivative is preferably used. The hindered phenol derivative is preferably used in the range of 0.1% by mass to 50% by mass with respect to the charge transport material 3.
The hindered amine derivative is preferably used in the range of 0.1% by mass to 50% by mass with respect to the charge transport material 3. A hindered phenol derivative and a hindered amine derivative may be mixed and used.
In this case, the total use amount of the hindered phenol derivative and the hindered amine derivative is preferably in the range of 0.1 mass% or more and 50 mass% or less with respect to the charge transport material 3.

  When the amount of hindered phenol derivative used, the amount of hindered amine derivative used, or the total amount of hindered phenol derivative and hindered amine derivative used is less than 0.1% by mass, the stability of the coating solution is improved and the durability of the photoreceptor is increased. It is not possible to obtain a sufficient effect for improvement. On the other hand, if it exceeds 50 mass%, the photoreceptor characteristics will be adversely affected. Therefore, the content is set to 0.1% by mass or more and 50% by mass or less.

Method for Forming Charge Transport Layer The charge transport layer 6 is prepared by, for example, the charge transport material 3 and the binder resin in an appropriate solvent, and, if necessary, the above-mentioned additives in the same manner as the above-described charge generation layer 5 is formed. Is dissolved or dispersed to prepare a coating solution for the charge transport layer, and this coating solution is applied onto the charge generation layer 5 by a spray method, a bar coating method, a roll coating method, a blade method, a ring method or a dip coating method. It is formed by doing. Among these coating methods, the dip coating method is particularly excellent in various respects as described above, and is often used when the charge transport layer 6 is formed.

  Solvents used in the coating solution include aromatic hydrocarbons such as benzene, toluene, xylene and monochlorobenzene, halogenated hydrocarbons such as dichloromethane and dichloroethane, ethers such as THF, dioxane and dimethoxymethyl ether, and N, N -1 type chosen from the group which consists of aprotic polar solvents, such as a dimethylformamide, is used individually or in mixture of 2 or more types. Further, a solvent such as alcohols, acetonitrile or methyl ethyl ketone can be further added to the above-described solvent as necessary.

The film thickness of the charge transport layer 6 is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 40 μm or less.
When the film thickness of the charge transport layer 6 is less than 5 μm, the charge holding ability on the surface of the photoreceptor is lowered.
On the other hand, if the thickness of the charge transport layer 6 exceeds 50 μm, the resolution of the photoreceptor is lowered.
Therefore, it was found that the preferred film thickness of the charge transport layer is 5 μm or more and 50 μm or less.

Additive for photosensitive layer To the photosensitive layer 4, one or more kinds of electron accepting substances and dyes may be further added in order to improve the sensitivity and suppress an increase in residual potential and fatigue during repeated use.

  Examples of the electron acceptor include acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride and 4-chloronaphthalic anhydride; cyano compounds such as tetracyanoethylene and terephthalmalondinitrile; and 4-nitrobenzaldehyde. Aldehydes; anthraquinones such as anthraquinone and 1-nitroanthraquinone; polycyclic or heterocyclic nitro compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitrofluorenone; and diphenoquinone compounds An electron-withdrawing material or a material obtained by polymerizing these electron-withdrawing materials can be used.

As the dye, for example, an organic photoconductive compound such as xanthene dye, thiazine dye, triphenylmethane dye, quinoline pigment or copper phthalocyanine can be used.
These organic photoconductive compounds function as optical sensitizers.
A protective layer may be provided on the surface of the photosensitive layer 4. By providing the protective layer, the printing durability of the photosensitive layer 4 can be improved, and chemical adverse effects on the photosensitive layer 4 such as ozone and nitrogen oxides generated by corona discharge when charging the surface of the photosensitive member. Can be prevented. For the protective layer, for example, a layer made of a resin, an inorganic filler-containing resin, an inorganic oxide, or the like is used.

  Moreover, you may add various additives, such as antioxidant, a sensitizer, and a ultraviolet absorber, to each layer of a photoreceptor as needed. As a result, the potential characteristics can be improved. Further, the stability of the coating solution when forming a layer by coating is increased. Further, it is possible to reduce fatigue deterioration when the photoreceptor is used repeatedly, and to improve durability.

In particular, examples of the antioxidant include phenolic compounds, hydroquinone compounds, tocopherol compounds, and amine compounds. These antioxidants are preferably used in the range of 0.1 mass% or more and 50 mass% or less with respect to the charge transport material 3.
When the amount of the antioxidant used is less than 0.1% by mass, it is not possible to obtain a sufficient effect for improving the stability of the coating solution and improving the durability of the photoreceptor.
On the other hand, if the amount of the antioxidant used exceeds 50% by mass, the photoreceptor characteristics are adversely affected.
Therefore, it was found that the preferred amount of the antioxidant used for the charge transport material is 0.1% by mass or more and 50% by mass or less.

Intermediate Layer FIG. 2 is a schematic cross-sectional view showing a simplified structure of an electrophotographic photosensitive member as another embodiment of the electrophotographic photosensitive member according to the present invention. The electrophotographic photosensitive member in FIG. 2 is similar to the electrophotographic photosensitive member shown in FIG. 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that an intermediate layer 8 is provided between the conductive support 1 and the photosensitive layer 4.

When there is no intermediate layer 8 between the conductive support 1 and the photosensitive layer 4, charges are injected from the conductive support 1 to the photosensitive layer 4, the chargeability of the photosensitive layer 4 is lowered, and it is erased by exposure. Surface charges other than those that should be reduced may cause defects such as fogging in the image.
In particular, when an image is formed using a reversal development process, a toner image is formed in a portion where the surface charge has decreased due to exposure. Therefore, if the surface charge decreases due to factors other than exposure, the toner adheres to a white background. An image fogging called a black spot where minute black spots are formed occurs, and the image quality is significantly deteriorated.

That is, due to defects in the conductive support 1 or the photosensitive layer 4, the chargeability is reduced in a minute region, and image fogging such as black spots occurs, resulting in a significant image defect.
By providing the intermediate layer 8 as described above, injection of charges from the conductive support 1 to the photosensitive layer 4 can be prevented, so that a decrease in chargeability of the photosensitive layer 4 can be prevented, and by exposure It is possible to suppress a decrease in surface charge other than that to be erased, and to prevent occurrence of defects such as fogging on the image.

  Further, by providing the intermediate layer 8, defects on the surface of the conductive support 1 can be covered to obtain a uniform surface, so that the film formability of the photosensitive layer 4 can be improved. Further, peeling of the photosensitive layer 4 from the conductive support 1 can be suppressed, and the adhesion between the conductive support 1 and the photosensitive layer 4 can be improved.

  For the intermediate layer 8, a resin layer or an alumite layer made of various resin materials is used. The resin material for forming the resin layer includes polyethylene resin, polypropylene resin, polystyrene resin, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyurethane resin, epoxy resin, polyester resin, melamine resin, silicone resin, polyvinyl butyral resin, and polyamide. Examples thereof include resins such as resins, copolymer resins containing two or more of repeating units constituting these resins, casein, gelatin, polyvinyl alcohol, and ethyl cellulose.

  Among these, it is preferable to use a polyamide resin, and it is particularly preferable to use an alcohol-soluble nylon resin. Preferred alcohol-soluble nylon resins include, for example, so-called copolymer nylon obtained by copolymerizing 6-nylon, 6,6-nylon, 6,10-nylon, 11-nylon, 2-nylon, and the like, and N-alkoxymethyl-modified. Examples thereof include resins obtained by chemically modifying nylon, such as nylon and N-alkoxyethyl-modified nylon.

  The intermediate layer 8 may contain particles such as a metal oxide. By containing these particles, the volume resistance value of the intermediate layer 8 can be adjusted to further prevent the injection of charge from the conductive support 1 to the photosensitive layer 4, and in the various environments Electrical characteristics can be maintained.

  Examples of metal oxide particles include particles of titanium oxide, aluminum oxide, aluminum hydroxide, tin oxide, and the like.

  When the intermediate layer 8 contains particles such as metal oxide, for example, these particles are dispersed in a resin solution in which the above-described resin is dissolved to prepare an intermediate layer coating solution. The intermediate layer 8 can be formed by coating on the support 1.

Water or various organic solvents are used as the solvent for the resin solution. In particular, single solvents such as water, methanol, ethanol or butanol ; or water and alcohols, two or more alcohols, acetone or dioxolane and alcohols, chlorinated solvents such as dichloroethane, chloroform and trichloroethane and alcohols, etc. A mixed solvent is preferably used.

  As a method for dispersing the aforementioned particles in the resin solution, a general method using a ball mill, a sand mill, an attritor, a vibration mill, an ultrasonic disperser, or the like can be used.

The total content C of the resin and metal oxide in the intermediate layer coating solution is such that C / D is 1/99 to 40 / in mass ratio with respect to the content D of the solvent used in the intermediate layer coating solution. 60 is preferable, and 2/98 to 30/70 is more preferable.
Further, the ratio of resin to metal oxide (resin / metal oxide) is preferably 90/10 to 1/99 by mass ratio, more preferably 70/30 to 5/95.

  Examples of the coating method of the intermediate layer coating liquid include a spray method, a bar coating method, a roll coating method, a blade method, a ring method, and a dip coating method. In particular, as described above, the dip coating method is relatively simple and excellent in terms of productivity and cost, and is therefore often used for forming the intermediate layer 8.

The film thickness of the intermediate layer 8 is preferably 0.01 μm or more and 20 μm or less, and more preferably 0.05 μm or more and 10 μm or less.
If the thickness of the intermediate layer 8 is less than 0.01 μm, the intermediate layer 8 substantially does not function as the intermediate layer 8, and it is impossible to obtain a uniform surface property by covering the defects of the conductive support 1. It becomes impossible to prevent the injection of charges from the body 1 to the photosensitive layer 4 and the chargeability of the photosensitive layer 4 is lowered.
Making the thickness of the intermediate layer 8 greater than 20 μm makes it difficult to form the intermediate layer 8 when the intermediate layer 8 is formed by dip coating, and makes the photosensitive layer 4 uniformly on the intermediate layer 8. Since it cannot be formed and the sensitivity of the photoreceptor is lowered, it is not preferable.

Single Layer Type Electrophotographic Photoreceptor FIG. 3 is a schematic cross-sectional view showing a simplified structure of an electrophotographic photoreceptor that is still another embodiment of the present invention. The electrophotographic photosensitive member in FIG. 3 is similar to the electrophotographic photosensitive member shown in FIG. 2, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  It should be noted that the electrophotographic photosensitive member in FIG. 3 has a single layer type electrophotographic film having a photosensitive layer 7 having a single layer structure in which both the charge generation material 2 and the charge transport material 3 are contained in a binder resin. It is a photoreceptor.

  The photosensitive layer 7 is formed by the same method as that for forming the charge transport layer 6 described above. For example, the charge generating material 2 described above, the charge transporting material 3 containing the organic photoconductive material of the present invention represented by the general formula (I), and a binder resin are dissolved or dispersed in the above-mentioned appropriate solvent to be sensitized. A layer coating solution is prepared, and this photosensitive layer coating solution is applied onto the intermediate layer 8 by a dip coating method or the like.

  The ratio of the charge transport material 3 and the binder resin in the photosensitive layer 7 is 10/12 to 10 by mass ratio, similar to the ratio A / B of the charge transport material 3 and the binder resin in the charge transport layer 6 described above. / 30.

The film thickness of the photosensitive layer 7 is preferably 5 μm or more and 100 μm or less, and more preferably 10 μm or more and 50 μm or less.
When the film thickness of the photosensitive layer 7 is less than 5 μm, the charge holding ability on the surface of the photoreceptor is lowered. When the film thickness of the photosensitive layer 7 exceeds 100 μm, the productivity is lowered.
Therefore, it was found that the preferred film thickness of the photosensitive layer 7 is 5 μm or more and 100 μm or less.

  The electrophotographic photosensitive member according to the present invention is not limited to the configuration shown in FIGS. 1 to 3 described above, and can adopt various layer configurations.

Next, an image forming apparatus including the electrophotographic photosensitive member according to the present invention will be described. The image forming apparatus according to the present invention is not limited to the following description.
FIG. 4 is a configuration diagram showing a simplified configuration of an image forming apparatus including the electrophotographic photosensitive member according to the present invention.

  As shown in FIG. 4, the image forming apparatus includes an electrophotographic photosensitive member (hereinafter also simply referred to as “photosensitive member”) according to the present invention. The photoconductor is cylindrical and is rotationally driven at a predetermined peripheral speed in the direction of reference numeral 41 by a driving means (not shown). Around the photosensitive member, a charger 32, a semiconductor laser (not shown), a developing device 33, a transfer charger 34, and a cleaner 36 are provided in this order along the rotation direction of the photosensitive member. A fixing device 35 is provided in the traveling direction of the transfer paper 51.

An image forming process by the image forming apparatus will be described. First, the photoreceptor is uniformly charged with a predetermined positive or negative potential on the surface of the photoreceptor (not shown) facing the charger 32 by a contact or non-contact charger 32. Next, a laser beam 31 is irradiated from a semiconductor laser (not shown), and the surface of the photoconductor is exposed.
The laser beam 31 is repeatedly scanned in the longitudinal direction of the photoconductor, which is the main scanning direction, and accordingly, electrostatic latent images are sequentially formed on the surface of the photoconductor. The electrostatic latent image is developed as a toner image by a developing device 33 provided on the downstream side in the rotation direction from the image forming point of the laser beam 31.

  In synchronism with the exposure of the photoreceptor, the transfer paper 51 is sent from the direction of reference numeral 42 to the transfer charger 34 provided on the downstream side in the rotation direction of the developing device 33.

The toner image formed on the surface of the photoconductor in the developing unit 33 is transferred onto the surface of the transfer paper 51 by the transfer charger 34.
The transfer paper 51 onto which the toner image has been transferred is transported to the fixing device 35 by a transport belt (not shown), and the toner image is fixed to the transfer paper 51 by the fixing device 35 to form a part of the image.

  The toner remaining on the surface of the photosensitive member is removed by a cleaner 36 provided with a neutralizing lamp (not shown) further downstream in the rotation direction of the transfer charger 34 and upstream in the rotation direction of the charger 32. By further rotating the photoreceptor, the above process is repeated, and an image is formed on the transfer paper 51. The transfer paper 51 on which the image is formed in this manner is discharged outside the image forming apparatus.

  As described above, the electrophotographic photosensitive member provided in the image forming apparatus contains the charge transport material of the present invention represented by the general formula (I) as an organic photoconductive material, and thus has a high charging potential and high sensitivity. Therefore, it exhibits sufficient photoresponsiveness and is excellent in durability, and their characteristics are not deteriorated even when used in a low temperature environment or in a high-speed process.

  Therefore, it is possible to obtain a highly reliable image forming apparatus capable of providing high quality images under various environments. In addition, since the performance of the electrophotographic photosensitive member does not deteriorate due to light exposure, it is possible to prevent deterioration of image quality due to exposure of the photosensitive member to light during maintenance or the like, and to improve the reliability of the image forming apparatus. it can.

  Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

Production Example 1
Manufacture example 1-1 of exemplary compound No. 1-1
Preparation of ketone intermediate (A) 2.3 g (1.0 equivalent) of 4-bromo-α-chloroacetophenone, 2.0 g (1.0 equivalent) of 5-bromosalicylaldehyde, and 2.6 g (2 of diisopropylethylamine) 0.05 equivalent) is dissolved in 50 ml of 1,4-dioxane and reacted at 100-110 ° C. for 5-6 hours. After completion of the reaction, the mixture was allowed to cool, and the precipitated crystals were separated by filtration and washed with cold ethanol to obtain 3.5 g of a powdery compound.

で示される化合物がケトン中間体（Ａ）として得られたことが判った（収率：９２％）。
また、ＬＣ−ＭＳの分析結果から、得られたケトン中間体（Ａ）の純度は９９.３％であることが判った。 As a result of analyzing the obtained compound by liquid chromatography-mass spectrometry (Liquid Chromatography-Mass Spectrometry: Abbreviation: LC-MS), the target ketone intermediate (A) (calculated molecular weight: 377.89) was obtained. Since a peak corresponding to the molecular ion [M + H] ⁺ to which protons were added was observed at 378.9, the following structural formula (IV):

It was found that the compound represented by the formula (1) was obtained as a ketone intermediate (A) (yield: 92%).
Moreover, from the analysis result of LC-MS, it turned out that the purity of the obtained ketone intermediate (A) is 99.3%.

で表されるホスフィン化合物０.０８ｇを計り取り、テトラヒドロフラン５ｍｌを入れ、攪拌溶解後、先のトルエン溶液に注入した。窒素気流下、８０℃で１６時間加熱攪拌した。混合物を室温に冷やし、温水５０ｍｌ、トルエン８０ｍｌを加え、攪拌、セライトろ過した。静置分液して、有機層をさらに温水８０ｍｌで洗浄、濃縮後、トルエンとヘプタン混合溶媒から再結晶して、粉末状化合物４.０５ｇを得た。
得られた化合物を液体クロマトグラフィー−質量分析法で分析した結果、目的とするケトン中間体（Ｂ）（分子量の計算値：６４０.３１）にプロトンが付加した分子イオン［Ｍ＋Ｈ］⁺に相当するピークが６４１.７に観測されたことから、下記構造式（ＩＸ）： Production Example 1-2
Preparation of ketone intermediate (B) In 80 ml of toluene, 3.5 g (2.1 equivalents) of (2,4-xylyl) -p-tolylamine as a secondary arylamine derivative represented by the above general formula (V) 3.0 g (1.0 equivalent) of the ketone intermediate (A) synthesized by the previous reaction was mixed with 1.8 g (2.4 equivalent) of sodium-t-butoxide. Separately, 0.02 g of palladium acetate and the following structural formula (VIII):

0.08 g of the phosphine compound represented by formula (5) was weighed, 5 ml of tetrahydrofuran was added, and after stirring and dissolving, it was poured into the toluene solution. The mixture was heated and stirred at 80 ° C. for 16 hours under a nitrogen stream. The mixture was cooled to room temperature, 50 ml of warm water and 80 ml of toluene were added, and the mixture was stirred and filtered through celite. The organic layer was further washed with 80 ml of warm water, concentrated and then recrystallized from a mixed solvent of toluene and heptane to obtain 4.05 g of a powdery compound.
As a result of analyzing the obtained compound by liquid chromatography-mass spectrometry, it corresponds to a molecular ion [M + H] ⁺ in which a proton is added to the target ketone intermediate (B) (calculated molecular weight: 640.31). Since a peak was observed at 641.7, the following structural formula (IX):

で示される化合物が、ケトン中間体（Ｂ）として得られたことが判った（収率：８０％）。また、ＬＣ−ＭＳの分析結果から、得られた構造式（ＩＸ）の化合物の純度は９９.1％であることが判った。

It was found that the compound represented by (1) was obtained as a ketone intermediate (B) (yield: 80%). Further, from the analysis result of LC-MS, it was found that the purity of the obtained compound of the structural formula (IX) was 99.1%.

で示されるシンナミルブロマイド１.９４ｇ（１.２当量）と金属マグネシウムパウダー２４０ｍｇ（１.２当量）からグリニヤール試薬を調整し、その溶液中に上記の製造例１−２でケトン中間体（Ｂ）として得られた前記構造式（ＩＸ）で示される３.１ｇ（１.０当量）を０℃で徐々に加えた、その後室温で1時間放置し、さらに４０℃まで加熱し、４０℃を保つように加熱しながら５時間撹拌した。反応混合物を放冷した後、過剰のメタノール中に注いだ。析出物を回収し、トルエンに溶解させてトルエン溶液とした。このトルエン溶液を分液ロートに移し、水洗した後、有機層を取出し、取出した有機層を硫酸マグネシウムで乾燥した。乾燥後、固形物を取除いた有機層を濃縮し、シリカゲルカラムクロマトグラフィーを行うことによって、黄色結晶３.４６ｇを得た。
得られた化合物を液体クロマトグラフィー−質量分析法で分析した結果、目的とする化合物（１）； Production Example 1-3
Production of Compound (1) In 20 ml of ethyl ether, as an allyl halide derivative represented by the above general formula (VII), the following structural formula (X):

A Grignard reagent was prepared from 1.94 g (1.2 equivalents) of cinnamyl bromide and 240 mg (1.2 equivalents) of metal magnesium powder, and the ketone intermediate (B ) 3.1 g (1.0 equivalent) represented by the structural formula (IX) obtained as above was gradually added at 0 ° C., then allowed to stand at room temperature for 1 hour, and further heated to 40 ° C. Stir for 5 hours while heating to keep. The reaction mixture was allowed to cool and then poured into excess methanol. The precipitate was collected and dissolved in toluene to obtain a toluene solution. The toluene solution was transferred to a separatory funnel, washed with water, the organic layer was taken out, and the taken out organic layer was dried over magnesium sulfate. After drying, the organic layer from which the solid was removed was concentrated and subjected to silica gel column chromatography to obtain 3.46 g of yellow crystals.
As a result of analyzing the obtained compound by liquid chromatography-mass spectrometry, the target compound (1);

で示される化合物（分子量の計算値：７４０.３８）にプロトンが付加した分子イオン［Ｍ＋Ｈ］⁺に相当するピークが７４１.８に観測されたことから、上記構造式（１）で示される化合物（１）が得られたことが判った（収率：８０％）。
また、ＬＣ−ＭＳの分析結果から、ケトン中間体（Ｂ）として得られた化合物の純度は９９.１％であることが判った。
上記製造例１−１〜１−３と同様な反応条件により、対応する原料からケトン中間体（Ａ）およびケトン中間体（Ｂ）を経由して、一般式（Ｖ）および（ＶＩＩ）で示される２級アリールアミン誘導体およびアリルハライド誘導体を適宜選択することにより、上記の表１に記載した化合物（２）〜（４０）も合成することが出来る。

A peak corresponding to the molecular ion [M + H] ⁺ in which a proton is added to the compound represented by formula (calculated molecular weight: 740.38) was observed at 741.8. Therefore, the compound represented by the above structural formula (1) It was found that (1) was obtained (yield: 80%).
Further, from the analysis result of LC-MS, it was found that the purity of the compound obtained as the ketone intermediate (B) was 99.1%.
Under the same reaction conditions as in Production Examples 1-1 to 1-3, the compounds represented by the general formulas (V) and (VII) from the corresponding raw materials via the ketone intermediate (A) and the ketone intermediate (B) are used. The compounds (2) to (40) shown in Table 1 above can also be synthesized by appropriately selecting the secondary arylamine derivative and allyl halide derivative.

The yield in each reaction of the compounds evaluated in the following examples, the purity of the final synthesized product, and the molecular ion [M + H] ⁺ for structure confirmation are shown in the following table.

で示されるアゾ化合物１質量部を、ＴＨＦ９９質量部にフェノキシ樹脂（ユニオンカーバイド社製：ＰＫＨＨ）１質量部を溶解させて得た樹脂溶液に加えた後、ペイントシェーカで２時間分散させ、電荷発生層用塗布液（５ｇ）を調製した。この電荷発生層用塗布液を、導電性支持体１である、表面にアルミニウムが蒸着された膜厚８０μｍのポリエステルフィルムのアルミニウム上にベーカアプリケータにて塗布した後、乾燥させ、膜厚０.３μｍの電荷発生層５を形成した。 Example 1
The following structural formula (41), which is the charge generation material 12:

Is added to a resin solution obtained by dissolving 1 part by mass of phenoxy resin (manufactured by Union Carbide Co., Ltd .: PKHH) in 99 parts by mass of THF, and then dispersed with a paint shaker for 2 hours to generate charge. A layer coating solution (5 g) was prepared. This coating solution for charge generation layer was applied to a conductive support 1 on a 80 μm thick polyester film with aluminum deposited on the surface using a bakery applicator, and then dried to obtain a film thickness of 0. A charge generation layer 5 having a thickness of 3 μm was formed.

Next, 8 parts by mass of the compound (1) which is an asymmetric butadiene compound shown in Table 1 as the charge transport material 3 and 10 parts by mass of a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Inc .: Z400) as a binder resin are added in THF80. Dissolve it in parts by mass and apply the charge transport layer coating solution (
5 g) was prepared. This coating solution for charge transport layer was applied on the charge generation layer 5 previously formed by a baker applicator and then dried to form a charge transport layer 6 having a thickness of 10 μm.
As described above, a multilayer electrophotographic photosensitive member having the structure shown in FIG. 1 was produced.

Examples 2-6
As the charge transport material 3, instead of the compound (1) which is an asymmetric butadiene compound, the compounds (2), (14), (15), (18) and (28) shown in the above table are used, respectively. In the same manner as in Example 1, electrophotographic photoreceptors were prepared in Examples 2 to 6, respectively.

で示される化合物（ａ）を用いる以外は、実施例１と同様にして電子写真感光体を作製した。 Comparative Example 1
Instead of the compound (1) which is an asymmetric butadiene compound as the charge transport material 3, the following structural formula (a):

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound (a) represented by

で示される化合物（ｂ）を用いる以外は、実施例１と同様にして電子写真感光体を作製した。 Comparative Example 2
Instead of the compound (1) which is an asymmetric butadiene compound as the charge transport material 3, the following structural formula (b):

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound (b) represented by

で示される化合物（ｃ）を用いる以外は、実施例１と同様にして電子写真感光体を作製した。 Comparative Example 3
Instead of the compound (1) which is an asymmetric butadiene compound as the charge transport material 3, the following structural formula (c):

An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound (c) represented by

[Evaluation 1]
About each electrophotographic photoreceptor produced in the above Examples 1 to 6 and Comparative Examples 1 to 3, the ionization potential on the surface of each electrophotographic photoreceptor was measured using a surface analyzer (manufactured by Riken Keiki Co., Ltd .: AC-1). It was measured.
In addition, gold was deposited on the surface of the photosensitive layer of each electrophotographic photoreceptor, and the charge mobility of the charge transport material 3 was measured by a time-of-flight method at room temperature and under reduced pressure.
Table 1 shows the results obtained in the above evaluation.

<Comprehensive evaluation>
The above ionization potential and charge mobility were comprehensively evaluated.
VG (very good): very good; charge mobility is 1.3 × 10 ^{−4 to} 2.0 × 10 ⁻⁴ ,
NB (not bad): not bad; charge activation is 2.0 × 10 ⁻⁵ ,
B (bad): Bad; charge mobility is 9.9 × 10 ⁻⁵ or less.
Each measurement result is shown in the following table.

なお、上記の表に示す電荷移動度の値は、電界強度が２.５×１０⁵Ｖ／ｃｍのときの値である。

The charge mobility values shown in the above table are values when the electric field strength is 2.5 × 10 ⁵ V / cm.

  From a comparison between Examples 1 to 6 and Comparative Examples 1, 2, and 3, the charge transport material of the present invention represented by the general formula (I) is a compound (a) or a compound ( Compared with enamine-styryl compounds such as b) and triphenylamine dimer (abbreviation: TPD) such as compound (c), it was found to have a charge mobility one digit or more higher.

Example 7
9 parts by mass of dendritic titanium oxide (Ishihara Sangyo Co., Ltd .: TTO-D-1) surface-treated with aluminum oxide (chemical formula: Al ₂ O ₃ ) and zirconium dioxide (chemical formula: ZrO ₂ ) and nylon copolymerized 9 parts by mass of a resin (Toray Industries, Inc .: CM8000) is added to a mixed solvent of 41 parts by mass of 1,3-dioxolane and 41 parts by mass of methanol, and dispersed for 12 hours using a paint shaker, and the coating solution for the intermediate layer (20 g) was prepared. The prepared coating solution for intermediate layer was applied on an aluminum substrate having a thickness of 0.2 mm, which is the conductive support 1, with a baker applicator and then dried to form an intermediate layer 8 having a thickness of 1 μm.

で示されるアゾ化合物２質量部を、ＴＨＦ９７質量部にポリビニルブチラール樹脂（積水化学工業株式会社製：ＢＸ−１）１質量部を溶解させて得た樹脂溶液に加えた後、ペイントシェーカで１０時間分散させ、電荷発生層用塗布液（５ｇ）を調製した。この電荷発生層用塗布液を、先に形成した中間層１８の上に、ベーカアプリケータにて塗布した後、乾燥させ、膜厚０.３μｍの電荷発生層１５を形成した。 Next, the following structural formula (42), which is the charge generation material 2:

Is added to a resin solution obtained by dissolving 1 part by mass of polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd .: BX-1) in 97 parts by mass of THF, and then 10 hours with a paint shaker. Dispersed to prepare a charge generation layer coating solution (5 g). This charge generation layer coating solution was applied onto the previously formed intermediate layer 18 with a baker applicator and then dried to form a charge generation layer 15 having a thickness of 0.3 μm.

Subsequently, 10 parts by mass of the compound (1) which is the asymmetric butadiene compound shown in Table 1 as the charge transport material 3, 14 parts by mass of the polycarbonate resin (M400 Gas Co., Ltd .: Z400) as the binder resin, 0.2 parts by mass of 6-di-t-butyl-4-methylphenol was dissolved in 80 parts by mass of THF to prepare a charge transport layer coating solution (5 g). This coating solution for charge transport layer was applied on the charge generation layer 15 previously formed by a baker applicator and then dried to form a charge transport layer 16 having a thickness of 18 μm.
As described above, a multilayer electrophotographic photosensitive member having the configuration shown in FIG. 2 was produced.

Examples 8-12
Instead of the compound (1) which is an asymmetric butadiene compound as the electric charge transport material 3, the compounds (14), (15), (18), (28) and (35) which are asymmetric butadiene compounds shown in Table 1 above are used. ) Were used in the same manner as in Example 7, except that each of the electrophotographic photoreceptors of Examples 8 to 12 was prepared.

Comparative Examples 4-5
Instead of the compound (1) which is an asymmetric butadiene compound as the charge transport material 3, the compound (a) represented by the structural formula (a) as a comparative compound or the compound (c) represented by the structural formula (c) The electrophotographic photoreceptors of Comparative Examples 4 and 5 were prepared in the same manner as in Example 7, except that each of the above was used.

Example 13
In the same manner as in Example 7, a coating solution for the intermediate layer was prepared, and this was applied onto an aluminum substrate having a thickness of 0.2 mm, which is the conductive support 1, and then dried to form an intermediate layer 8 having a thickness of 1 μm. Formed.

Next, 1 part by mass of 3,5-dimethyl-3 ′, 5′-di-t-butyldiphenoquinone, which is the charge generation material 2, and polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Inc .: Z-) 400) 12 parts by mass, 10 parts by mass of the asymmetric butadiene compound of Exemplified Compound No. 1 shown in Table 6 which is the charge transport material 13, 3,5-dimethyl-3 ′, 5′-di-t-butyldiphenoquinone 5 Part by weight, 0.5 part by mass of 2,6-di-t-butyl-4-methylphenol and 65 parts by mass of THF were dispersed by a ball mill for 12 hours to prepare a photosensitive layer coating solution (5 g). The prepared photosensitive layer coating solution is applied onto the previously formed intermediate layer 8 with a bakery applicator and then dried with hot air at 110 ° C. for 1 hour to form the photosensitive layer 7 having a thickness of 20 μm shown in FIG. did.
As described above, a single-layer electrophotographic photosensitive member having the configuration shown in FIG. 3 was produced.

Example 14
Example 7 except that X-type metal-free phthalocyanine (Dainippon Ink Chemical Industries, Ltd .: Fastgen Blue 8120BS) is used as the charge generation material 2 instead of the azo compound represented by the structural formula (42). Thus, an electrophotographic photosensitive member was produced.

Examples 15-19
X-type metal-free phthalocyanine is used as the charge generation material 2 instead of the azo compound represented by the structural formula (42), and the compound (2) shown in Table 1 is used as the charge transport material 3 instead of the compound (1). ), (15), (18), (28), and (35), respectively, except that the asymmetric butadiene compounds were used, respectively, to prepare electrophotographic photoreceptors according to Examples 15 to 19 in the same manner as Example 14.

Comparative Examples 6 and 7
X-type metal-free phthalocyanine is used as the charge generation material 2 instead of the azo compound represented by the structural formula (42), and the charge transporting material 3 is replaced with the structural formula (1) instead of the compound (1). Electrophotographic photoreceptors according to Comparative Examples 6 and 7 were prepared in the same manner as in Example 14 except that the compound (a) represented by a) or the compound (c) represented by the structural formula (c) was used. did.

[Evaluation 2]
For each of the electrophotographic photosensitive members produced in Examples 7 to 19 and Comparative Examples 4 to 7, initial characteristics and repeat characteristics were measured using an electrostatic copying paper test apparatus (manufactured by Kawaguchi Electric Co., Ltd .: EPA-8200). evaluated. The evaluation of the initial characteristics and the repetitive characteristics is as follows: room temperature / normal humidity environment (hereinafter referred to as N / N environment) at a temperature of 22 ° C. and a relative humidity of 65% (22 ° C./65% RH). The temperature was 5 ° C. and the relative humidity was 20% (5 ° C./20% RH) in a low temperature / low humidity environment (hereinafter referred to as an L / L environment).

  The initial characteristics were evaluated as follows. The surface of the photosensitive member was charged by applying a minus (−) 5 kV voltage to the photosensitive member, and the surface potential of the photosensitive member at this time was measured as a charged potential V0 (V).

However, in the case of the single layer type photoreceptor of Example 13, a voltage of plus (+) 5 kV was applied.
Next, the charged photoreceptor surface was exposed. At this time, the energy required to halve the surface potential of the photoreceptor from the charging potential V0 was measured as a half-exposure amount E1 / 2 (μJ / cm ² ) and used as an evaluation index for sensitivity. Further, the surface potential of the photosensitive member at the time when 10 seconds passed from the start of exposure was measured as a residual potential Vr (V), and used as an evaluation index of photoresponsiveness.
In the exposure, in the case of the photoconductors of Examples 7 to 12 and Comparative Examples 4 and 5 in which the azo compound represented by the structural formula (42) is used as the charge generation material 2, the exposure energy is 1 μW / cm ^2. White light was used.

In the case of the photoreceptors of Examples 14 to 19 and Comparative Examples 6 and 7, X-type metal-free phthalocyanine was used as the charge generating material 2 and the wavelength obtained by spectroscopy with a monochromator was 780 nm, and the exposure energy was 1 μW / cm. ² light was used.

Evaluation of repetitive characteristics was performed as follows. After the above-described charging and exposure operations were repeated 5000 times as one cycle, the half-exposure amount E1 / 2, the charging potential V0, and the residual potential Vr were measured in the same manner as the evaluation of the initial characteristics.
<Comprehensive evaluation>
The absolute value of V _r in the above repetitive characteristics under the N / N environment and the L / L environment, ie, | V _r | is in the range of 10 to 40 as VG (very good), Either or both of them are outside the above range, but those with | V _r | of 65 or less were defined as NB (not bad).

The above measurement results are shown in the following table.

From the comparison between Examples 7 to 12 and Comparative Examples 4 and 5 and the comparison between Examples 14 to 19 and Comparative Examples 6 and 7, the organic material of the present invention represented by the general formula (I) is used as the charge transport material 3. The photoconductors of Examples 7 to 12 and 14 to 19 using the photoconductive material are the photoconductors of Comparative Examples 4 to 7 using the compound (a) or the compound (c) as the comparative compound for the charge transport material 3. It was found that the half-exposure amount E1 / 2 is smaller than that of the body, the sensitivity is small, and the residual potential Vr is low in the negative direction.
It was also found that this characteristic is maintained even when used repeatedly, and further maintained in a low temperature / low humidity (L / L) environment.

Example 20
9 parts by mass of dendritic titanium oxide (Ishihara Sangyo Co., Ltd .: TTO-D-1) surface-treated with aluminum oxide (Al ₂ O ₃ ) and zirconium dioxide (ZrO ₂ ) and copolymer nylon resin (Toray Industries, Inc.) 9 parts by mass (CM8000) was added to a mixed solvent of 41 parts by mass of 1,3-dioxolane and 41 parts by mass of methanol, and then dispersed for 8 hours with a paint shaker to obtain an intermediate layer coating solution (1. 5 kg) was prepared. The intermediate layer coating solution is filled in a coating tank, and an aluminum cylindrical conductive support 1 having a diameter of 30 mm, a total length of 357 mm, and a thickness of 0.8 mm is dipped in the coating tank and then pulled up to obtain a film thickness of 1 An intermediate layer 8 having a thickness of 0.0 μm was formed on the conductive support 1.

  Next, 40 g of o-phthalodinitrile, 18 g of titanium tetrachloride, and 500 ml of α-chloronaphthalene were reacted by heating and stirring at 200 to 250 ° C. for 3 hours in a nitrogen atmosphere as oxotitanium phthalocyanine that is the charge generation material 2. The mixture was allowed to stand until it dropped to ˜130 ° C., filtered while hot, and washed with 200 ml of α-chloronaphthalene heated to 100 ° C. to obtain a crude dichlorotitanyl phthalocyanine product. This crude product was washed with 200 ml of α-chloronaphthalene and then with 200 ml of methanol at room temperature, and further subjected to hot washing in 500 ml of methanol for 1 hour. Thereafter, filtration was performed, and the obtained crude product was repeatedly washed with hot water until the pH reached 6 to 7 in 500 ml of ion-exchanged water while exchanging the ion-exchanged water. Crystal structure obtained after drying and showing a clear diffraction peak at least at a Bragg angle (2θ ± 0.2 °) of 27.2 ° in an X-ray diffraction spectrum by Cu-Kα characteristic X-ray (wavelength: 1.54Å) 2 parts by mass of oxotitanium phthalocyanine having 1 part, polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd .: ESREC BM-S) and 97 parts by mass of methyl ethyl ketone are mixed and dispersed by a paint shaker to generate charges. A layer coating solution (1.5 kg) was prepared. By applying this coating solution for charge generation layer onto the intermediate layer 8 formed earlier by the same method as the intermediate layer 8 formed earlier, that is, by dip coating, a charge generation with a film thickness of 0.4 μm is generated. Layer 5 was formed on the intermediate layer 8.

Next, 10 parts by mass of the compound (1) as an asymmetric butadiene compound as the charge transport material 3, 20 parts by mass of a polycarbonate resin (manufactured by Mitsubishi Gas Chemical Co., Inc .: Z-400) as a binder resin, and 2,6-di- 1 part by mass of t-butyl-4-methylphenol and 0.004 part by mass of dimethylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd .: KF-96) are dissolved in 110 parts by mass of tetrahydrofuran to obtain a coating solution for a charge transport layer. (1.5 kg) was prepared. This charge transport layer coating solution is applied onto the charge generation layer 5 formed earlier by the same dip coating method as that of the previously formed intermediate layer 8, and then dried at 110 ° C. for 1 hour, A 23 μm charge transport layer 6 was formed.
An electrophotographic photosensitive member was produced as described above.

Examples 21 and 22
The charge transport material 3 was replaced with the compound (1) as an asymmetric butadiene compound in the same manner as in Example 20, except that the compound (14) and the asymmetric butadiene compound (18) shown in Table 1 were used. Electrophotographic photosensitive members according to Examples 21 and 22 were produced.

Comparative Example 8
An electrophotographic photoreceptor is prepared in the same manner as in Example 20, except that the compound (a) represented by the structural formula (a) is used as the asymmetric butadiene compound instead of the compound (1) as the charge transport material 3. Produced.

Example 23
An electrophotographic photosensitive member was produced in the same manner as in Example 20 except that the amount of the polycarbonate resin as the binder resin of the charge transport layer 6 was 25 parts by mass.

Examples 24 and 25
The amount of the polycarbonate resin that is the binder resin of the charge transport layer 6 is 25 parts by mass, and the charge transport material 3 is a compound that is an asymmetric butadiene compound shown in Table 1 instead of the compound (1) as an asymmetric butadiene compound ( 14) or an electrophotographic photoreceptor according to Examples 24 and 25 was prepared in the same manner as in Example 20 except that the compound (35) was used.

Reference example 1
An electrophotographic photosensitive member was produced in the same manner as in Example 20 except that the amount of the polycarbonate resin as the binder resin of the charge transport layer 6 was 10 parts by mass.

Reference example 2
An electrophotographic photosensitive member was produced in the same manner as in Example 20 except that the amount of the polycarbonate resin as the binder resin of the charge transport layer 6 was 31 parts by mass.
However, when the charge transport layer 6 was formed, the same amount of tetrahydrofuran as in Example 20 could not be used to prepare a charge transport layer coating solution in which the polycarbonate resin was completely dissolved. Was prepared, and a charge transport layer 6 was formed using the charge transport layer coating solution.
However, since the amount of the solvent in the coating solution for the charge transport layer is excessive, white turbidity occurs due to the brushing phenomenon at the end in the longitudinal direction of the cylindrical photoconductor, and the characteristics cannot be evaluated.

[Evaluation 3]
The electrophotographic photoreceptors prepared in Examples 20 to 25, Comparative Example 8, and Reference Examples 1 and 2 were evaluated for printing durability and stability of electrical characteristics as follows.

Each of the produced electrophotographic photosensitive members was mounted on a digital copying machine (manufactured by Sharp Corporation: MX-3100FG). After 40,000 sheets of images were formed, the film thickness d1 of the photosensitive layer was measured, and the difference between this value and the film thickness d0 of the photosensitive layer at the time of production was obtained as a film reduction amount Δd (= d0−d1) An evaluation index for printing durability was used.

In addition, a surface potential meter (Gentec Corporation: CATE751) is provided in the copying machine so that the surface potential of the photoconductor in the image forming process can be measured, and charged in an N / N environment of 22 ° C./65% RH. The charging potential V0 (V), which is the surface potential immediately after, and the surface potential VL (V) immediately after the exposure with the laser beam were measured.
Similarly, the surface potential VL immediately after the exposure with the laser beam was measured in an L / L environment of 5 ° C./20% RH. The difference between VL (1) and VL (2) when the surface potential VL measured in the N / N environment is VL (1) and the surface potential VL measured in the L / L environment is VL (2). Was obtained as a potential fluctuation ΔL (= VL (2) −VL (1)) and used as an evaluation index of the stability of electrical characteristics. The photosensitive member surface was charged by a negative charging process.

These evaluation results are shown in Table 5.
The amount of film slip Δd is 5 or less, and the absolute value of L / L-potential fluctuation ΔV _L , that is, | Δ
Those with V _L | of 20 or more were designated as VG (very good), and others were designated as NB (not bad).

From comparison between Examples 20 to 25 and Comparative Example 8, Comparative Compound A was used for Examples 20 to 25 using the organic photoconductive material of the present invention as the charge transport material 13 and the photoreceptor of Reference Example 1. It was found that the surface potential VL in the N / N environment was small and the photoresponsiveness was excellent even when the binder resin was added at a high ratio as compared with the photoreceptor of Comparative Example 8 that was present.
Further, the magnitude of the potential fluctuation ΔVL was small, and it was found that sufficient photoresponsiveness was exhibited even in an L / L environment.

  From comparison between Examples 20 to 25 and Reference Example 1, the ratio A / B of the charge transport material (A) to the binder resin (B) is in the range of 10/12 to 10/30. The photoreceptor A has a smaller film reduction amount Δd and higher printing durability than the photoreceptor of Reference Example 1 in which the ratio A / B is 10/10 and exceeds 10/12 and the binder resin ratio is low. I found out.

  As described above, by forming the charge transport layer by containing the organic photoconductive material of the present invention, it was possible to improve the printing durability of the charge transport layer without reducing the photoresponsiveness.

  As described above, according to the present invention, the organic photoconductive material has a specific structure, i.e., an asymmetric bisbutadiene, and is excellent in compatibility with the binder resin, such as precipitation of an electrotransport material during film formation. By using an organic photoconductive material with high charge mobility that does not cause problems, it has a high charging potential, high sensitivity, sufficient photoresponsiveness, excellent durability, and low temperature environment or When used in a high-speed process, it is possible to provide a highly reliable electrophotographic photosensitive member that does not deteriorate their characteristics even when exposed to light.

  Further, according to the present invention, the charging potential is high, the sensitivity is high, the photoresponsiveness is sufficient, the durability is excellent, and the characteristics are not deteriorated even when used in a low temperature environment or a high-speed process. In addition, since a highly reliable electrophotographic photosensitive member that does not deteriorate their characteristics even when exposed to light is provided, a highly reliable image forming apparatus capable of providing high-quality images in various environments is provided. In addition, the image quality can be prevented from being deteriorated due to exposure of the photosensitive member to light during maintenance and the reliability of the image forming apparatus can be improved.

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Charge generation material 3 Charge transport material 4, 7 Photosensitive layer 5 Charge generation layer 6 Charge transport layer 8 Intermediate layer 31 Laser beam 32 Charger 33 Developing device 34 Transfer charger 35 Fixing device 36 Cleaner 51 Transfer paper

Claims (9)

A layered photosensitive layer in which a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material are laminated in this order, or a single layer type photosensitive layer containing a charge generating material and a charge transporting material is conductively supported The charge transport layer or the single-layer type photosensitive layer is formed on a body as a charge transport material, and is represented by the following general formula (I):

(In the formula, Ar ₁ and Ar ₂ represent an aryl group which may contain a substituent, Ar ₃ and Ar ₄ represent a hydrogen atom or an aryl or heteroaryl group which may have a substituent)
An electrophotographic photoreceptor comprising an asymmetric butadiene compound represented by the formula: In the general formula (I), the Ar ₁ and Ar ₂ independently of each other have the following formula:

A group represented by
Ar ₃ and Ar ₄ each independently represent a hydrogen atom, or the following formula:

The photoconductor according to claim 1, wherein Ar ₃ and Ar ₄ are not simultaneously hydrogen atoms.
In the general formula (I), the Ar ₁ is represented by the following formula:

A group represented by
The Ar ₂ is represented by the following formula:

A group represented by
The Ar ₃ is represented by the following formula:

And Ar ₄ is a hydrogen atom or the following formula:

The photoreceptor according to claim 1, which is a group represented by the formula: In the general formula (I), the Ar ₁ is represented by the following formula:

A group represented by
The Ar ₂ is represented by the following formula:

A group represented by
The Ar ₃ is represented by the following formula:

And Ar ₄ is a hydrogen atom or the following formula:

The photoconductor according to claim 1, wherein the photoconductor is a group represented by the formula:   The charge transport layer or the single layer type photosensitive layer further contains a binder resin, and the charge transport layer (A) and the binder resin (B) in the charge transport layer or the single layer type photosensitive layer. The electrophotographic photosensitive member according to any one of claims 1 to 4, wherein A / B is 10/12 to 10/30 by mass ratio.   The charge generation layer or the single-layer type photosensitive layer has a clear diffraction peak at a Bragg angle (2θ ± 0.2 °) of at least 27.2 ° in Cu-Kα characteristic X-ray diffraction (wavelength: 1.54 mm). The electrophotographic photosensitive member according to any one of claims 1 to 5, comprising oxotitanium phthalocyanine having a charge generating substance.   The electrophotographic photosensitive member according to claim 1, further comprising an intermediate layer between the multilayer photosensitive layer or the single-layer photosensitive layer and the conductive support.   An image forming apparatus comprising the electrophotographic photosensitive member according to claim 1.   The image forming apparatus according to claim 8, wherein the image forming apparatus forms an image using a reversal development process.

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