JP2013003340A - Electrophotographic photoreceptor and image forming apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoreceptor exhibiting high sensitivity and sufficient photo-responsiveness and having excellent gas resistance, and to provide an image forming apparatus having the photoreceptor.SOLUTION: The electrophotographic photoreceptor includes, as a photosensitive layer 14, a laminate photosensitive layer in which a charge generating layer 15 containing a charge generating substance 12 and a charge transporting layer 16 containing a charge transporting substance 13 are layered in this order, or a monolayer type photosensitive layer containing a charge generating substance and a charge transporting substance, formed on a conductive support 11. The charge transporting layer or the monolayer type photosensitive layer contains a triarylamine dimer compound expressed by general formula (I) as a charge transporting substance.

Description

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

  In recent years, organic photoconductive materials have been extensively researched and developed and are not only used for electrostatic recording elements such as photoreceptors, but are also beginning to be applied to sensor elements, organic electroluminescent (EL) elements, and the like. .

  Organic photoconductors using organic photoconductive materials have good film-forming properties, excellent flexibility, light weight, good transparency, and a wide wavelength range by appropriate sensitization methods. However, it has been gradually developed as the main force of the photoconductor because it has an advantage that a photoconductor showing good sensitivity can be easily designed.

  Organic photoreceptors initially had drawbacks in sensitivity and durability, but these drawbacks were the development of function-separated photoreceptors in which the charge generation function and charge transport function were shared by different substances. Is significantly improved. In addition to the above-mentioned advantages of the organic photoconductor, this function-separated type photoconductor also has the advantage that a wide range of materials can be selected for the photosensitive layer and a photoconductor having arbitrary characteristics can be produced relatively easily. Have.

  Such an organic photoreceptor has a single-layer structure in which both a charge generation material and a charge transport material (also referred to as “charge transfer material”) are dispersed in a binder resin on a support, and a charge on the support. Various configurations such as a stacked structure or a reverse two-layer stacked structure in which a charge generation layer in which a generated material is dispersed in a binder resin and a charge transport layer in which a charge transport material is dispersed in a binder resin are formed in this order or in reverse order Has been proposed. Among these, the functionally separated type photoconductor, in which a charge transport layer is laminated on the charge generation layer as the photosensitive layer, is excellent in electrophotographic characteristics and durability, and various characteristics of the photoconductor can be designed with a high degree of freedom in material selection. It is widely used because it can be done.

  The charge generating materials used in these functionally separated photoreceptors include various materials such as phthalocyanine pigments, squarylium dyes, azo pigments, perylene pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes, and pyrylium salt dyes. Various materials that have been studied and have high light resistance and high charge generation ability have been proposed.

  As charge transport materials, various compounds such as pyrazoline compounds, hydrazone compounds, triphenylamine compounds, stilbene compounds, enamine compounds are known.

  Various performances such as higher speed, durability, and sensitivity stability are required for the photoreceptor having the configuration proposed or studied in this way. In particular, in response to reversal development type electrophotographic apparatuses such as recent digital copying machines and laser printers, high sensitivity corresponding to high speed as photoconductor characteristics and durability by improving wear resistance and sensitivity stability = Coexistence with long life is required. In addition, higher image reliability and repetitive stability are required for photoreceptors used in laser printers and the like.

  Among these, high sensitivity has recently been achieved by the use of enamine charge transport materials having high mobility as disclosed in, for example, JP 2000-112157 A (Patent Document 1) and JP 2004-334125 A (Patent Document 2). Developed and realized.

However, it has been considered that one of the major disadvantages of these photoreceptors is that their durability is generally lower than that of inorganic photoreceptors. Durability is broadly divided into durability of electrophotographic physical properties such as sensitivity, residual potential, charging ability, and image blur, and mechanical durability such as abrasion and scratches on the surface of the photoreceptor due to rubbing. The main cause of the decrease in the durability of electrophotographic physical properties is that ozone, NO _x (nitrogen oxide), etc. generated by corona discharge or deterioration of the charge transport material contained in the surface layer of the photoconductor by light irradiation. Are known. Many charge transport materials composed of various skeletons that have been proposed are also being improved considerably in terms of durability, but they are still not sufficient.

  In addition, the photoreceptor is used repeatedly in the system, and always requires constant and stable electrophotographic characteristics. With respect to such stability and durability, the present situation is that a sufficient product has not been obtained in any configuration.

  That is, the potential decreases, the residual potential increases, the sensitivity changes, and the like with repeated use, and the copy quality is lowered and cannot be used. All of these causes of degradation have not been elucidated, but there are several possible causes.

  For example, it has been found that oxidative gases such as ozone and nitrogen oxides emitted from a corona discharge charger cause significant damage to the photosensitive layer. These oxidizing gases chemically change the material in the photosensitive layer and cause various characteristic changes. For example, a decrease in charging potential, an increase in residual potential, and a decrease in resolving power due to a decrease in surface resistance. As a result, image blurring such as white spots and black bands occur on the output image, which significantly reduces image quality, It shortens the life of the body. For such a phenomenon, proposals to incorporate measures to efficiently exhaust and replace the gas around the corona charger to avoid direct gas influence on the photoreceptor, and antioxidants and stabilizers in the photosensitive layer There is also a proposal to prevent deterioration by adding.

  For example, JP-A-62-105151 (Patent Document 3) discloses that an antioxidant having a triazine ring and a hindered phenol skeleton in the molecule is added to the photosensitive layer, and JP-A-63-18355 ( Patent Document 4) discloses that a specific hindered amine is added to the photosensitive layer. JP-A 63-4238 (Patent Document 5), JP-A 63-216055 (Patent Document 6) and JP-A-3-172852 (Patent Document 7) disclose trialkylamines, aromatics. JP-A-5-158258 (Patent Document 8) discloses addition of an amine group to the photosensitive layer, and addition of an amine dimer to the photosensitive layer. In most cases, the addition of this additive has a problem that the electrical characteristics of the photoreceptor deteriorate.

JP 2000-112157 A JP 2004-334125 A JP 62-105151 A JP-A-63-18355 Japanese Unexamined Patent Publication No. 63-4238 Japanese Patent Laid-Open No. 63-216055 JP-A-3-172852 JP-A-5-158258

That is, such a conventional technique has not yet achieved a sufficient gas resistance effect, and addition of such an antioxidant deteriorates electrophotographic characteristics such as sensitivity and residual potential. However, the current situation is that there are still problems that are insufficient for practical use.
Therefore, new material proposals that improve gas resistance and have no harmful effect on electrophotographic characteristics are struggling.

  Accordingly, an object of the present invention is to provide a photoconductor having high sensitivity and sufficient photoresponsiveness and excellent gas resistance, and an image forming apparatus including the photoconductor.

As a result of intensive research, the present inventors have found that white spots on the output image are caused by NOx and other gases emitted from the corona discharge charger interact with the charge transport material in the photosensitive layer. It is also a phenomenon that occurs due to a decrease in surface resistance due to adhering to the surface layer, and its degree greatly affects the structure of the charge transport material.
Therefore, as a result of examining the structure having a small interaction with NOx, the present inventors introduced an alkyl group at the ortho position of the phenyl group of the phenylamine structure in order to shield the N atom in the structure of the charge transport material. I found it useful.

  In addition, when an alkyl group is introduced at this site, the conjugated system is reduced, so the mobility is considerably lowered and the responsiveness is deteriorated. However, by having two stilbene or butadiene units, the compound of the present invention has a gas resistance. It has been found that it has high sensitivity and sufficient photoresponsiveness.

  Furthermore, it has been newly found that wear resistance is improved by introducing an alkyl group at the ortho position of the amino group. Further, these have been found to be extremely useful for a photoreceptor and an image forming apparatus equipped with the same. The invention has been completed.

［式中、
Ａｒ¹はアリール又は複素環基であり、これらの基は置換基を有してもよく；
Ａｒ²は、水素原子あるいはアルキル、アラルキルもしくはアリール基または一価複素環基であり、これらの基は置換基を有してもよく；
Ｒ¹はアルキル基であり、この基は置換基を有してもよく；
Ｒ²及びＲ³は、互いに同一または異なって、水素原子またはアルキル基であり、これらの基は置換基を有してもよく；
Ｒ⁴及びＲ⁵は、互いに同一または異なって、水素原子またはアルキルもしくはアルコキシ基であり、これらの基は置換基を有してもよく；
ｎは０または１である］
で示されるトリアリールアミンダイマー化合物を含む電子写真感光体が提供される。 Thus, according to the present invention, as the photosensitive layer, 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 charge generation material and a charge transport layer. A single-layer type photosensitive layer containing a substance 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 substance:

[Where:
Ar ¹ is an aryl or heterocyclic group, and these groups may have a substituent;
Ar ² is a hydrogen atom or an alkyl, aralkyl or aryl group or a monovalent heterocyclic group, and these groups may have a substituent;
R ¹ is an alkyl group, which may have a substituent;
R ² and R ³ are the same or different from each other, and are a hydrogen atom or an alkyl group, and these groups may have a substituent;
R ⁴ and R ⁵ are the same or different from each other and are a hydrogen atom or an alkyl or alkoxy group, and these groups may have a substituent;
n is 0 or 1]
An electrophotographic photoreceptor comprising the triarylamine dimer compound represented by the formula:

According to the present invention, the charge generating material has a diffraction peak at a Bragg angle (2θ ± 0.2 °) of at least 27.2 ° in Cu-Kα characteristic X-ray diffraction (wavelength: 1.541). An electrophotographic photoreceptor that is oxotitanium phthalocyanine is provided.
According to the present invention, the photosensitive layer is a laminated photosensitive layer in which a charge generation layer containing the charge generation material and a charge transport layer containing the charge transport material are laminated in this order. An electrophotographic photoreceptor is provided.

  In addition, according to the present invention, there is provided the electrophotographic photoreceptor, further comprising an intermediate layer between the conductive support and the photosensitive layer.

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.

When the triarylamine dimer compound of the present invention is contained in the photosensitive layer as a charge transport material, it is possible to provide a photoreceptor having excellent gas resistance, high sensitivity, and sufficient photoresponsiveness.
Therefore, by incorporating the charge transport material according to the present invention in the photosensitive layer of the photoreceptor, it is possible to provide a photoreceptor that has an effect of ozone resistance and at the same time has excellent durability and environmental stability.
Further, even when the photoreceptor of the present invention is used in a high-speed electrophotographic process, it can provide a high-quality image due to its excellent gas resistance effect.

Therefore, by using the photoconductor according to the present invention, it is possible to form a high-quality image excellent in gas resistance even when used repeatedly for a long period of time.
Further, since the photoconductor according to the present invention can provide a high-quality image even in a high-speed electrophotographic process, the image forming apparatus according to the present invention can increase the image forming speed.

  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 can efficiently inject 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 (I) 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, 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 electrophotographic photoreceptor according to the present invention is excellent in gas resistance, has high sensitivity, and has sufficient photoresponsiveness, so that it can provide a high-quality image under various environments. A forming device can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional view showing a simplified configuration of a multilayer electrophotographic photosensitive member 1 which is a first embodiment of an electrophotographic photosensitive member according to the present invention. FIG. 3 is a partial cross-sectional view showing a simplified configuration of a multilayer electrophotographic photosensitive member 2 as a second embodiment of the electrophotographic photosensitive member according to the present invention. It is a fragmentary sectional view which simplifies and shows the structure of the single layer type electrophotographic photoreceptor 3 which is the third embodiment of the electrophotographic photoreceptor according to the present invention. 1 is a side view schematically illustrating a configuration of an image forming apparatus 100 that is an embodiment of an image forming apparatus according to the present invention.

［式中、
Ａｒ¹はアリール又は複素環基であり、これらの基は置換基を有してもよく；
Ａｒ²は、水素原子あるいはアルキル、アラルキルもしくはアリール基または一価複素環基であり、これらの基は置換基を有してもよく；
Ｒ¹はアルキル基であり、この基は置換基を有してもよく；
Ｒ²及びＲ³は、互いに同一または異なって、水素原子またはアルキル基であり、これらの基は置換基を有してもよく；
Ｒ⁴及びＲ⁵は、互いに同一または異なって、水素原子またはアルキルもしくはアルコキシ基であり、これらの基は置換基を有してもよく；
ｎは０または１である］
で示される化合物である。 [Organic photoconductive material]
The triarylamine dimer compound contained in the electrophotographic photosensitive member according to the present invention as a charge transport material has the following general formula (I):

[Where:
Ar ¹ is an aryl or heterocyclic group, and these groups may have a substituent;
Ar ² is a hydrogen atom or an alkyl, aralkyl or aryl group or a monovalent heterocyclic group, and these groups may have a substituent;
R ¹ is an alkyl group, which may have a substituent;
R ² and R ³ are the same or different from each other, and are a hydrogen atom or an alkyl group, and these groups may have a substituent;
R ⁴ and R ⁵ are the same or different from each other and are a hydrogen atom or an alkyl or alkoxy group, and these groups may have a substituent;
n is 0 or 1]
It is a compound shown by these.

Specifically, in the compound of the general formula (I), in the Ar ¹ , the aryl group is a phenyl, naphthyl, tetrahydronaphthyl, biphenyl or fluorenyl group, or the heterocyclic group is furyl, thienyl, thiazolyl, A benzofuryl, phenylbenzofuryl or carbazolyl group, which may be substituted by one or more halogen atoms or a linear or branched C ₁ -C ₄ alkyl or alkoxy group, or phenoxy Or optionally substituted with a phenylthio group;

In Ar ² , the alkyl group is methyl, ethyl, n-propyl, isopropyl, t-butyl, cyclohexyl or cyclopentyl group, the aralkyl group is benzyl or phenethyl group, or the aryl group is phenyl, naphthyl, tetrahydro A naphthyl, biphenyl or fluorenyl group, or the monovalent heterocyclic group is a furyl, thienyl, thiazoyl, benzofuryl, benzothiophenyl or benzothiazoyl group, these groups comprising one or more halogen atoms or or it may be substituted by straight-chain or branched C ₁ -C ₄ alkyl or alkoxy group, or a phenyl, phenoxy, may be substituted by phenylthio or naphthyl group;

The alkyl group in R ¹ is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group, and these groups may be substituted with a halogen atom;
The alkyl group in R ² and R ³ is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group, and these groups may be substituted with a hydrogen atom or a halogen atom;

The alkyl group in R ⁴ and R ⁵ is methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group, or the alkoxy group is methoxy, ethoxy, n-propoxy, isopropoxy, n -Butoxy or t-butoxy group, which is a triarylamine dimer compound which may be substituted with a hydrogen atom or a halogen atom.

More specifically, in the compound of the general formula (I), the aryl group in Ar ¹ is a phenyl, naphthyl, tetrahydronaphthyl or biphenyl group, or the heterocyclic group is a furyl, thienyl, thiazolyl or benzofuryl group. And these groups may be substituted with one or more halogen atoms or linear or branched C ₁ -C ₄ alkyl, alkoxy or alkylene groups;

The alkyl group in Ar ² is a methyl, ethyl, n-propyl, isopropyl or t-butyl group, or the aryl group is a phenyl, naphthyl or biphenyl group, or the monovalent heterocyclic group Is a furyl, thienyl or thiazolyl group which is substituted with one or more halogen atoms or a linear or branched C ₁ -C ₄ alkyl or alkoxy group, a phenyl, phenoxy or naphthyl group Well;

The alkyl group in R ¹ is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group;
The alkyl group in R ² and R ³ is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group;

In the R ⁴ and R ⁵ , the alkyl group is a methyl or ethyl group, or the alkoxy group is a triarylamine dimer compound in which a methoxy or ethoxy group is used.

More specifically, in the compound of the general formula (I), Ar ¹ is phenyl, p-tolyl, m-tolyl, 1-naphthyl, 2-naphthyl or 5,6,7,8-tetrahydro-1- A naphthyl group,
Ar ² is a hydrogen atom or an isopropyl, phenyl, p-tolyl, benzyl or thienyl group;

R ¹ is a methyl, ethyl or isopropyl group;
R ² and R ³ are a hydrogen atom or a methyl or ethyl group,
R ⁴ and R ⁵ are a triarylamine dimer compound which is a hydrogen atom or an o-methyl, p-methyl or p-methoxy group.

（式中、Ａｒ¹、Ｒ¹およびＲ²は、前記一般式（Ｉ）において定義したとおりである）
で示されるトリアリールアミンダイマー化合物をフォルミル化反応に付して、次の一般式（ＩＩＩ）： In the present invention, the charge transport material represented by the general formula (I) contained in the photosensitive layer can be produced, for example, as follows.
First, the following formula (II):

(In the formula, Ar ¹ , R ¹ and R ² are as defined in the general formula (I)).
A triarylamine dimer compound represented by the following general formula (III):

（式中、Ａｒ¹、Ｒ¹およびＲ²は、前記一般式（Ｉ）において定義したとおりである）
で示されるアルデヒド化合物を製造する。

(In the formula, Ar ¹ , R ¹ and R ² are as defined in the general formula (I)).
Is produced.

  This reaction is carried out in a solvent such as N, N-dimethylformaldehyde, 1,2-dichloroethane, phosphorus oxychloride / N, N-dimethylformaldehyde, phosphorus oxychloride / N-methyl-N-phenylformaldehyde or phosphorus oxychloride. 2 to 2.5 equivalents of Vilsmeier reagent adjusted with / N, N-diphenylformaldehyde and 1.0 equivalent of the triarylamine dimer compound represented by the above formula (II) at 60 to 110 ° C. It is synthesized by heating and stirring for 8 hours, followed by hydrolysis with an aqueous solution of 1 to 8 N sodium hydroxide or an alkaline aqueous solution such as potassium hydroxide.

（式中、Ａｒ²、Ｒ³およびＲ⁵は、前記一般式（Ｉ）において定義したとおりであり、Ｒ⁶は置換基を有してもよいアルキル基又はアリール基を示す） Finally, the aldehyde compound represented by the above general formula (III) and the following general formula (IV):

(In the formula, Ar ² , R ³ and R ⁵ are as defined in the general formula (I), and R ⁶ represents an alkyl group or an aryl group which may have a substituent)

（式中、Ａｒ²、Ｒ³およびＲ⁵は、前記一般式（Ｉ）において定義したとおりであり、Ｒ⁷は置換基を有してもよいアルキル基又はアリール基を示す）
で示されるウィッティッヒ（Wittig）試薬とを塩基性条件下で反応させるウィッティッヒ−ホルナー（Wittig-Horner）反応を行うことによって、本発明の前記一般式（Ｉ）で示される化合物を製造することができる。 Or (V):

(In the formula, Ar ² , R ³ and R ⁵ are as defined in the general formula (I), and R ⁷ represents an alkyl group or an aryl group which may have a substituent)
The compound represented by the general formula (I) of the present invention can be produced by performing a Wittig-Horner reaction in which a Wittig reagent represented by formula (I) is reacted under basic conditions. .

  At this time, when the Wittig reagent represented by the general formula (IV) is used, among the enamine compounds represented by the general formula (I), those having a stilbene structure in which n is 0 can be obtained. When the Wittig reagent represented by the formula (V) is used, an enamine compound represented by the general formula (I) having a butadiene structure in which n is 1 can be obtained.

The Wittig-Horner reaction can be performed, for example, as follows.
In an appropriate solvent, 1.0 equivalent of the aldehyde represented by the general formula (III), 2.0 to 2.4 equivalent of the Wittig reagent represented by the general formula (IV) or (V), and a metal alkoxide The charge transport material represented by the general formula (I) is produced in a high yield by stirring 2.0 to 3.0 equivalents at room temperature or under heating at 30 to 60 ° C. for 2 to 8 hours. be able to.

Examples of the solvent that can be used for the Wittig-Horner reaction include solvents such as toluene, xylene, diethyl ether, tetrahydrofuran (THF), ethylene glycol dimethyl ether, N, N-dimethylformamide, and dimethyl sulfoxide (DMSO).
Examples of the metal alkoxide include potassium t-butoxide, sodium ethoxide, sodium methoxide, and the like.

  Specific examples of the charge transport material of the present invention represented by the general formula (I) include compounds having groups shown in the following table. However, the organic photoconductive material of the present invention is not limited by the following compounds.

表中、Ｍｅはメチル基を意味し、Ｅｔはエチル基を意味し、ｉ−Ｐｒはイソプロピル基を意味し、ＯＭｅはメトキシ基を意味する。

In the table, Me means a methyl group, Et means an ethyl group, i-Pr means an isopropyl group, and OMe means a methoxy group.

  Among the compounds represented by the general formula (I), compounds particularly excellent as organic photoconductive materials from the viewpoint of their electrical properties, cost, productivity, etc. include compounds 5, 9, 15, 16, in Table 1. 17, 18, 25, 26, 35 and 36 are preferred.

[Electrophotographic photoreceptor]
The electrophotographic photoreceptor of the present invention includes 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 charge generation material and a charge transport material. A single layer type photosensitive layer is formed on a conductive support, and the charge transport layer or the single layer type photosensitive layer is used as the charge transport material in the general formula (I), particularly the compounds 5, 9 in Table 1. , 15, 16, 17, 18, 25, 26, 35, and 36 are laminated type electrophotographic photoreceptors or single layer type electrophotographic photoreceptors.

Embodiments of an electrophotographic photosensitive member and an image forming apparatus according to the present invention will be described below with reference to the accompanying drawings.

  The electrophotographic photosensitive member and the image forming apparatus of the present invention are not limited to the embodiments described below, and include other forms in which various modifications are made without departing from the gist of the present invention. Of course, such other forms are easily understood by those skilled in the art based on the description of the present specification and the drawings.

[Laminated electrophotographic photoreceptor]
Embodiment 1
FIG. 1 is a partial cross-sectional view showing a simplified configuration of an electrophotographic photoreceptor 1 which is a first embodiment of the electrophotographic photoreceptor according to the present invention. In the present embodiment, the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer.

  The electrophotographic photosensitive member 1 includes a sheet-like conductive support 11 made of a conductive material, a charge generation layer 15 that is a layer laminated on the conductive support 11 and contains a charge generation material 12, a charge A charge transport layer 16 that is stacked on the generation layer 15 and contains the charge transport material 13. The charge generation layer 15 and the charge transport layer 16 constitute a stacked photosensitive layer 14 that is a photosensitive layer. That is, the photoreceptor 1 is a laminated photoreceptor.

<Conductive support>
The conductive support 11 serves as an electrode for the photoreceptor 1 and also functions as a support member for the other layers 15 and 16. The shape of the conductive support 11 is illustrated as a sheet, but is not limited thereto, and may be, for example, a columnar shape, a cylindrical shape, or an endless belt shape.

  In the present invention, the conductive support may be any conductive support that can be used for the photoreceptor. As the conductive material constituting the conductive support 11, for example, a single metal such as aluminum, copper, zinc, or titanium, or an alloy such as an aluminum alloy or stainless steel can be used.

  Furthermore, without being limited to these metal materials, for example, a polymer material such as polyethylene terephthalate, nylon or polystyrene, a laminate of metal foil on the surface of a substrate such as hard paper or glass, or a metal material is deposited. Or a layer obtained by depositing or coating a layer of a conductive compound such as a conductive polymer, tin oxide, or indium oxide can also be used. These conductive materials are processed into an appropriate shape and used as a conductive support for the photoreceptor.

  If necessary, the surface of the conductive support 11 may be subjected to an anodic oxide coating 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 wavelengths of the laser light are uniform, so the laser light reflected on the surface of the photoconductor and the laser light reflected inside the photoconductor cause interference, and the interference due to this interference. Stripes may appear on the image and cause image defects. By performing the above-described treatment on the surface of the conductive support 11, image defects due to interference of laser light having the same wavelength can be prevented.

<Charge generation layer>
The charge generation layer 15 provided on the conductive support 11 contains a charge generation material 12 that generates charges by absorbing light.

(Charge generating material)
Examples of the charge generation material include azo pigments such as monoazo pigments, bisazo pigments and trisazo pigments, indigo pigments such as indigo and thioindigo, perylene pigments such as peryleneimide and perylene anhydride, anthraquinone and pyrenequinone, etc. Polycyclic quinone pigments, metal phthalocyanines such as oxotitanium phthalocyanine compounds and phthalocyanine compounds such as metal-free phthalocyanines, squarylium dyes, pyrylium salts and thiopyrylium salts, organic photoconductive materials such as triphenylmethane dyes, and selenium and non- Examples thereof include inorganic photoconductive materials such as crystalline silicon.

One of these charge generation materials may be used alone, or two or more of these charge generation materials may be used in combination.
Among these charge generation materials, it is preferable to use phthalocyanine compounds, particularly oxotitanium phthalocyanine compounds.

  The oxotitanium phthalocyanine compound used in the present invention is oxotitanium phthalocyanine and its derivatives. As the oxotitanium phthalocyanine derivative, for example, a hydrogen atom of an aromatic ring contained in a phthalocyanine group of oxotitanium phthalocyanine is substituted with a halogen atom such as a chlorine atom or a fluorine atom, a substituent such as a nitro group, a cyano group or a sulfonic acid group. And those in which a ligand such as a chlorine atom is coordinated to a titanium atom which is a central metal of oxotitanium phthalocyanine.

  The oxotitanium phthalocyanine compound preferably has a specific crystal structure. Of the oxotitanium phthalocyanine compounds, the X-ray diffraction spectrum for Cu-Kα characteristic X-ray (wavelength: 1.54 Å) is preferably diffracted at a Bragg angle 2θ (error: ± 0.2 °) 27.2 °. The thing which has the crystal structure which shows a peak is mentioned. Here, the Bragg angle 2θ is an angle formed by incident X-rays and diffracted X-rays, and represents a so-called diffraction angle.

When such an oxotitanium phthalocyanine compound is used as a charge generation material in combination with the charge transport material represented by the general formula (I), a photoconductor excellent in gas resistance and sensitivity and resolution can be realized. This is particularly preferred because
That is, since the oxotitanium phthalocyanine compound is excellent in charge generation capability and charge injection capability, it generates a large amount of charge by absorbing light, and does not accumulate the generated charge in the charge transport layer 16. Can be injected efficiently.

On the other hand, since the charge transport material 13 is a compound having a high charge mobility represented by the general formula (I), the charge generated in the charge generation material 12 due to light absorption is efficiently transferred to the charge transport material 13. Therefore, it is possible to obtain a high-sensitivity and high-resolution electrophotographic photosensitive member.
The oxotitanium phthalocyanine compound can be produced according to a conventionally known production method such as, for example, a method described in Phthhalocyanine Compounds by Moser and Thomas, Reinhold Publishing Corp., New York, 1963.

  For example, oxotitanium phthalocyanine synthesizes dichlorotitanium phthalocyanine by melting and melting phthalonitrile and titanium tetrachloride in a suitable solvent such as α-chloronaphthalene, followed by base or water. It can be produced by hydrolysis. Alternatively, oxotitanium phthalocyanine can also be produced by reacting isoindoline with titanium tetraalkoxide such as tetrabutoxytitanium in a suitable solvent such as N-methylpyrrolidone.

(Sensitizer)
The charge generating substance may be used in combination with other sensitizing dyes (sensitizers). By adding a sensitizer, the sensitivity of the photoreceptor can be improved, and further, increase in residual potential and decrease in charging potential due to repeated use can be suppressed, and electrical durability can be improved.

  Examples of such sensitizing dyes include triphenylmethane dyes typified by methyl violet, crystal violet, knight blue and victoria blue, erythrosine, rhodamine B, rhodamine 3R, acridine orange and frapeosin. Examples include sensitizing dyes such as acridine dyes, thiazine dyes typified by methylene blue and methylene green, oxazine dyes typified by capri blue and meldra blue, cyanine dyes, styryl dyes, pyrylium salt dyes or thiopyrylium salt dyes. .

(Binder resin for charge generation layer)
The charge generation layer 15 may contain a binder resin in order to improve the binding property. Examples of the binder resin include 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 resin, and polyvinyl butyral resin. And a resin such as polyvinyl formal resin, and a copolymer resin containing two or more repeating units constituting these resins.

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. Can be mentioned.
The binder resin is not limited to the above, and a resin generally used in this field can be used as the binder resin. Binder resin may be used individually by 1 type, or 2 or more types may be used together.

The ratio of the charge generation material in the charge generation layer 15 is preferably 10 to 99% by weight.
If the ratio of the charge generation material is less than 10% by weight, the sensitivity of the photoreceptor may be lowered.
On the other hand, if the ratio of the charge generation material exceeds 99% by weight, the binder resin content is too low, and the film strength of the charge generation layer 15 may be reduced.

Further, the dispersibility of the charge generation material in the charge generation layer 15 is reduced, the coarse particles of the charge generation material are increased, the surface charge other than the portion to be erased is reduced by exposure, and the image defect, particularly toner on a white background There is a possibility that the fogging of an image called so-called black spots, which adhere and form minute black spots, increases.
The coating solution for the charge generation layer can be prepared, for example, by adding the above-described charge generation material and, if necessary, the above-described binder resin in a suitable solvent and dispersing by a conventionally known method.

(Solvent for charge generation layer coating solution)
Solvents used in the coating solution for the charge generation layer include, for example, 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 and dioxane Ethers such as 1,2-dimethoxyethane, etc .; alkyl ethers of ethylene glycol; aromatic hydrocarbons such as benzene, toluene, xylene; and aprotic substances such as N, N-dimethylformamide and N, N-dimethylacetamide Polar solvents and the like.
One of these solvents may be used alone, or two or more thereof may be mixed and used as a mixed solvent.

(Coating solution for charge generation layer)
The charge generation material may be pulverized in advance by a pulverizer before being dispersed in the solvent. 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 dispersing the charge generating substance in the solvent 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.

(Method for forming charge generation layer)
As a method for forming the charge generation layer 15, a vacuum deposition method in which the above-described charge generation material is vacuum-deposited on the surface of the conductive support 11, and a charge generation layer coating solution containing the charge generation material is used as the conductive support 11. The coating method etc. which apply | coat to the surface of this are mentioned. Among these, a simple coating method is preferably used.

  Examples of the coating method for the charge generation 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. Among these coating methods, in particular, the dip coating method is a method of forming a layer on the surface of the substrate by immersing the substrate in a coating tank filled with a coating solution and then pulling it up at a constant speed or a sequentially changing speed. It is relatively simple and excellent in terms of productivity and cost, and is therefore preferably used.

  In order to stabilize the dispersibility of the coating liquid, the apparatus used for the dip coating method may be provided with a coating liquid dispersing apparatus represented by an ultrasonic generator. Note that the coating method is not limited to these, and an optimum method can be appropriately selected in consideration of physical properties and productivity of the coating solution.

The film thickness of the charge generation layer 15 is preferably 0.05 to 5 μm, more preferably 0.1 to 1 μm.
If the thickness of the charge generation layer 15 is less than 0.05 μm, the light absorption efficiency is lowered, and the sensitivity of the photoreceptor 1 may be lowered. Further, when the film thickness of the charge generation layer 15 exceeds 5 μm, the charge transfer inside the charge generation layer 15 becomes a rate-determining step in the process of erasing the charge on the surface of the photosensitive layer 14, and the sensitivity of the photoreceptor 1 may be lowered. is there.

<Charge transport layer>
The charge transport layer 16 includes the charge transport material 13 in the binder resin and has a function of transporting charges generated in the charge generation layer 15. As the charge transport material 13, the charge transport material of the present invention represented by the general formula (I) may be used alone or in admixture of two or more. Thereby, it is possible to obtain a photoconductor excellent in gas resistance, having high sensitivity, and having sufficient photoresponsiveness.
The compound represented by the general formula (I) may be used as a mixture with another charge transport material.

  Examples of such 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, and 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, phenylene Examples thereof include diamine derivatives, 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.

(Binder resin for charge transport layer coating solution)
As the binder resin 17 for forming the charge transport layer 16, a resin having excellent compatibility with the charge transport material 13 is selected.

Specific examples of such a binder resin include, for example, a vinyl polymer resin such as a polymethyl methacrylate resin, a polystyrene resin, and a polyvinyl chloride resin, and a copolymer resin including two or more of repeating units constituting them. And polycarbonate resin, polyester resin, polyester carbonate resin, polysulfone resin, phenoxy resin, epoxy resin, silicone resin, polyarylate resin, polyamide resin, polyether resin, polyurethane resin, polyacrylamide resin, and phenol resin. Moreover, the thermosetting resin which partially bridge | crosslinked these resin is also mentioned.
One of these resins may be used alone, or two or more of these resins may be mixed and used.

Among the above resins, polystyrene resin, polycarbonate resin, polyarylate resin or polyphenylene oxide has a volume resistivity of 10 ¹³ Ω · cm or more, excellent electrical insulation, and also has film property and potential characteristics. Since it is excellent, it is preferably used.
In the charge transport layer 16, the weight ratio (B / A) of the weight (B) of the binder resin to the weight (A) of the charge transport material is preferably 1.2 to 3.0.

The printing durability of the charge transport layer 16 can be improved by setting the ratio B / A to 1.2 or more and adding the binder resin to the charge transport layer 16 at a high ratio.
When a conventionally known charge transport material is used, if the binder resin ratio is increased in this way, the content of the charge transport material is lowered as a result, and the photoresponsiveness of the photoreceptor may be insufficient.

  On the other hand, since the compound represented by the general formula (I) of the present invention has an excellent charge transport capability, the ratio B / A is 1.2 or more, and the ratio of the binder resin in the charge transport layer 16 is as follows. Even if the height of the photosensitive member 1 is increased, the photosensitive member 1 exhibits sufficiently high photoresponsiveness and can provide a high-quality image.

That is, by using the compound represented by the general formula (I) according to the present invention as a charge transport material, the photoreceptor 1 can improve the printing durability of the charge transport layer 16 without decreasing the photoresponsiveness. And mechanical durability is improved.
On the other hand, if the ratio B / A exceeds 3.0, the binder resin ratio becomes too high, and the sensitivity of the photoreceptor 1 may decrease.

Further, when the charge transport layer 16 is formed by a dip coating method, the viscosity of the coating solution increases, the coating speed decreases, and the productivity may be remarkably deteriorated. If the amount of the solvent in the coating solution is increased in order to suppress an increase in the viscosity of the coating solution, a brushing phenomenon occurs, and the formed charge transport layer 16 may become cloudy.
When the ratio B / A is less than 1.2, the binder resin ratio becomes too low, the printing durability of the charge transport layer 16 decreases, the amount of film loss of the photosensitive layer 14 increases, and the charge of the photosensitive member 1 increases. May decrease.

(Additive for charge transport layer)
In order to improve the film formability, flexibility and surface smoothness, an additive such as a plasticizer and / or a leveling agent may be added to the charge transport layer 16 as necessary.
Examples of the plasticizer include dibasic acid esters such as phthalate esters, fatty acid esters, phosphate esters, chlorinated paraffins, and epoxy type plasticizers.
Examples of the leveling agent include silicone type leveling agents such as dimethyl silicone, diphenyl silicone, and phenylmethyl silicone.

  In addition, fine particles of an inorganic compound and / or an organic compound may be added to the charge transport layer 16 in order to increase mechanical strength and improve electrical characteristics. Specific examples of such inorganic compounds include fine metal oxide particles such as silica, alumina, and titanium oxide. Specific examples of organic compound fine particles include fine particles of fluorine atom-containing polymers such as tetrafluoroethylene polymer fine particles.

  The charge transport layer 16 may contain various additives such as an antioxidant and / or a sensitizer as necessary. 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, hindered phenol derivatives, hindered amine derivatives or benzylamine derivatives are preferably used. A hindered phenol derivative, a hindered amine derivative, and a benzylamine derivative may be mixed and used in an arbitrary ratio.

The amount of hindered phenol derivative, hindered amine derivative or benzylamine derivative used, or the total amount of hindered phenol derivative, hindered amine derivative and benzylamine derivative used is in the range of 0.1 to 50% by weight with respect to charge transport material 13. Is preferred.
By making the amount used 0.1% by weight or more, further effects can be obtained in improving the stability of the coating solution and improving the durability of the photoreceptor. If the amount used exceeds 50% by weight, the photoreceptor characteristics may be adversely affected.

(Solvent for charge transport layer coating solution)
Examples of the solvent used in the coating solution for the charge transport layer 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 aprotic polar solvents such as N, N-dimethylformamide.

A solvent may be used individually by 1 type, or 2 or more types may be mixed and used for it.
Further, if necessary, a solvent such as alcohols, acetonitrile or methyl ethyl ketone can be further added to the above solvent.

(Method for forming charge transport layer)
The charge transport layer 16 is prepared by, for example, dissolving or dispersing the charge transport material 13 and the binder resin 17 and, if necessary, the aforementioned additives in an appropriate solvent, as in the case of forming the aforementioned charge generation layer 15. It is formed by preparing a coating solution for charge transport layer and coating the coating solution on the charge generation layer 15 by spray method, bar coating method, roll coating method, blade method, ring method or dip coating method. . 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 16 is formed.

The film thickness of the charge transport layer 16 is preferably 5 to 50 μm, more preferably 10 to 40 μm.
If the thickness of the charge transport layer 16 is less than 5 μm, the charge holding ability of the surface of the photoreceptor may be lowered. If the thickness of the charge transport layer 16 exceeds 50 μm, the resolution of the photoreceptor 1 may be lowered.

(Sensitizer for charge transport layer)
Each layer of the photosensitive layer 14, that is, the charge generation layer 15 and / or the charge transport layer 16, includes one or more sensitizers such as an electron acceptor and a dye within a range that does not impair the preferred characteristics of the present invention. It may be added.
By adding the sensitizer, the sensitivity of the photoreceptor is improved, and the increase in residual potential and fatigue due to repeated use are suppressed, and the electrical durability is improved.

  Examples of the electron acceptor include acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride, 4-chloronaphthalic anhydride, cyano compounds such as tetracyanoethylene and terephthalmalondinitrile, 4-nitrobenzaldehyde, and the like. Aldehydes, anthraquinones such as anthraquinone and 1-nitroanthraquinone, polycyclic or heterocyclic nitro compounds such as 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, and diphenoquinone compounds The electron-withdrawing material can be used. Moreover, what polymerized these electron-withdrawing materials can also be used.

  As a sensitizer such as a dye, for example, an organic photoconductive compound such as a xanthene dye, a thiazine dye, a triphenylmethane dye, a quinoline pigment, or copper phthalocyanine can be used. These organic photoconductive compounds function as optical sensitizers.

  In the present embodiment, the photosensitive layer 14 has a stacked structure in which the charge generation layer 15 and the charge transport layer 16 formed as described above are stacked. Since the charge generation function and the charge transport function are assigned to separate layers as described above, the materials constituting each layer can be independently selected. Therefore, the most suitable materials for the charge generation function and the charge transport function can be selected. You can choose. Therefore, the photoreceptor 1 is particularly excellent in electrical characteristics such as chargeability, sensitivity, and photoresponsiveness, and electrical and mechanical durability.

Embodiment 2
FIG. 2 is a partial cross-sectional view showing a simplified configuration of an electrophotographic photoreceptor 2 which is a second embodiment of the electrophotographic photoreceptor according to the present invention. The electrophotographic photosensitive member 2 of this embodiment is similar to the electrophotographic photosensitive member 1 of the first embodiment shown in FIG. 1, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

<Intermediate layer>
What should be noted in the electrophotographic photoreceptor 2 is that an intermediate layer 18 is provided between the conductive support 11 and the photosensitive layer 14.
When there is no intermediate layer 18 between the conductive support 11 and the photosensitive layer 14, charges are injected from the conductive support 11 into the photosensitive layer 14, and the chargeability of the photosensitive layer 14 is reduced, so that the portion other than the exposed portion is not exposed. The surface charge of the image may be reduced and defects such as fogging may occur in the image. In particular, when an image is formed by using a reversal development process, a toner image is formed by attaching toner to a portion where the surface charge has been reduced by exposure. Therefore, if the surface charge decreases due to a factor other than exposure, There is a possibility that fogging of an image called black spots where toner adheres to the surface and minute black spots are formed may cause a significant deterioration in image quality.

  In the present photoreceptor 2, as described above, the intermediate layer 18 is provided between the conductive support 11 and the photosensitive layer 14, thereby preventing charge injection from the conductive support 11 to the photosensitive layer 14. . Therefore, it is possible to prevent the chargeability of the photosensitive layer 14 from being lowered, to suppress the reduction of the surface charge at portions other than the exposed portion, and to prevent the occurrence of defects such as fogging on the image.

Further, by providing the intermediate layer 18, it is possible to cover the defects on the surface of the conductive support 11 and obtain a uniform surface, so that the film formability of the photosensitive layer 14 can be improved.
Furthermore, since the intermediate layer 18 functions as an adhesive that bonds the conductive support 11 and the photosensitive layer 14, peeling of the photosensitive layer 14 from the conductive support 11 can be suppressed.

  Conventionally, when the intermediate layer 18 is provided between the conductive support 11 and the photosensitive layer 14 as described above, the sensitivity of the photosensitive member may be lowered. However, in this photoreceptor 2, since the photosensitive layer 14 contains the charge transport material according to the present invention having an excellent charge transport capability, the sensitivity is not lowered by providing the intermediate layer 15. That is, according to the present invention, the intermediate layer can be provided on the photoreceptor without reducing the sensitivity.

(Resin material for intermediate layer)
As the intermediate layer 18, a resin layer made of various resin materials, an alumite layer, or the like is used.
Examples of the resin material constituting the resin layer include polyethylene resin, polypropylene resin, polystyrene resin, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyurethane resin, epoxy resin, polyester resin, melamine resin, silicone resin, and polyvinyl butyral resin. And synthetic resins such as polyamide resins, and copolymer resins containing two or more of the repeating units constituting these synthetic resins. Moreover, casein, gelatin, polyvinyl alcohol, ethyl cellulose, and the like are also included.

  Of these resins, polyamide resins are preferably used, and alcohol-soluble nylon resins are particularly preferably used. 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, 12-nylon, and the like, and N-alkoxymethyl. Examples thereof include resins obtained by chemically modifying nylon such as modified nylon and N-alkoxyethyl-modified nylon.

(Intermediate layer additive)
Further, the intermediate layer 18 may contain particles such as metal oxide particles. By containing these particles in the intermediate layer 18, the volume resistance value of the intermediate layer can be adjusted, and the effect of preventing the injection of charges from the conductive support 11 to the photosensitive layer 14 can be enhanced. In addition, the electrical characteristics of the photoreceptor 2 can be maintained under various environments, and environmental stability can be improved. Examples of the metal oxide particles that can be included include particles of titanium oxide, aluminum oxide, aluminum hydroxide, tin oxide, and the like.

  The intermediate layer 18 can be formed by, for example, preparing an intermediate layer coating solution by dissolving or dispersing the resin in a suitable solvent and applying the coating solution to the surface of the conductive support 11. it can. When the intermediate layer 18 contains particles such as the above-described metal oxide particles, for example, these particles are dispersed in a resin solution obtained by dissolving the resin in an appropriate solvent. The intermediate layer 18 can be formed by preparing a coating solution and coating the coating solution on the surface of the conductive support 11.

(Solvent for intermediate layer coating solution)
As the solvent for the intermediate layer coating solution, water, various organic solvents, or a mixed solvent thereof is used. Among them, a single solvent 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 or trichloroethane and alcohols, A mixed solvent of ethers such as THF and dioxane and alcohols is preferably used.

(Method for forming intermediate layer)
As a method for dispersing the metal oxide particles in the resin solution, a known dispersion method using a ball mill, a sand mill, an attritor, a vibration mill, an ultrasonic disperser, a paint shaker, or the like can be used.

  In the intermediate layer coating solution, the weight ratio (C / D) of the total weight (C) of the resin and metal oxide to the weight (D) of the solvent used in the intermediate layer coating solution is 1/99 to The ratio is preferably 40/60, more preferably 2/98 to 30/70.

  The weight ratio (E / F) of the resin weight (E) to the metal oxide weight (F) is preferably 90/10 to 1/99, 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. Among these, the dip coating method is relatively simple as described above, and is excellent in terms of productivity and cost. Therefore, the dip coating method is also preferably used when forming an intermediate layer.

The film thickness of the intermediate layer 18 is preferably 0.01 to 20 μm, more preferably 0.05 to 10 μm.
If the thickness of the intermediate layer 15 is less than 0.01 μm, it will not substantially function as the intermediate layer 18, and it will not be possible to obtain uniform surface properties by covering the defects of the conductive support 11. There is a possibility that the injection of charges from the support 11 to the photosensitive layer 14 cannot be sufficiently prevented, and there is a possibility that a decrease in the chargeability of the photosensitive layer 14 cannot be suppressed.

  Making the thickness of the intermediate layer 18 greater than 20 μm makes it difficult to form the intermediate layer when formed by dip coating, and allows the photosensitive layer 14 to be uniformly formed on the intermediate layer. Therefore, the sensitivity of the photoreceptor 2 may be lowered, which is not preferable.

  Also in the present embodiment, various additives such as plasticizers, leveling agents, and / or fine particles of inorganic compounds and / or organic compounds are added to the charge transport layer 16 in the same manner as in the first embodiment. Also good. Further, an additive such as a sensitizer such as an electron accepting substance and / or a dye, an antioxidant, and / or an ultraviolet absorber is added to the charge generation layer 15 and / or the charge transport layer 16 of the photosensitive layer 14. Also good.

Embodiment 3
[Single-layer type electrophotographic photoreceptor]
FIG. 3 is a partial cross-sectional view showing a simplified configuration of an electrophotographic photosensitive member 3 as a third embodiment of the electrophotographic photosensitive member according to the present invention. The electrophotographic photosensitive member 3 of the present embodiment is similar to the electrophotographic photosensitive member 2 of the second embodiment shown in FIG. 2, and corresponding portions are denoted by the same reference numerals and description thereof is omitted.

  It should be noted in the electrophotographic photoreceptor 3 that the photosensitive layer 14 has a single layer structure composed of a single layer containing both a charge generating material and a charge transport material. That is, the photoconductor 3 is a single layer type photoconductor.

  The single-layer type photoreceptor 3 of the present embodiment is suitable as a photoreceptor for a positively charged image forming apparatus that generates less ozone, and has only one photosensitive layer 14 to be coated. In addition, the yield is superior to that of the multilayer photoreceptors 1 and 2 of the first and second embodiments.

  The photosensitive layer 14 binds the above-described general formula (I), particularly the compound (5), (15), (17) or (26), and the above-described charge generating substance as a charge transporting substance with a binder resin. Can be formed. As the binder resin, for example, those exemplified as the binder resin of the charge transport layer 13 in the first embodiment can be used.

  The photosensitive layer 14 has a sensitizer such as a plasticizer, a leveling agent, fine particles of an inorganic compound and / or an organic compound, an electron accepting substance and / or a dye, as in the photosensitive layer 14 in the first embodiment. Various additives such as an antioxidant and / or an ultraviolet absorber may be added.

  The photosensitive layer 14 can be formed by the same method as the charge transport layer 16 provided on the photoreceptor 1 of the first embodiment. For example, the charge generating material, the charge transport material according to the present invention represented by the general formula (I) and appropriate amounts of the binder resin, and various charge transport materials other than the charge transport material of the present invention as required An appropriate amount of the additive is dissolved or dispersed in an appropriate solvent similar to the charge transport layer coating solution of the first embodiment to prepare a photosensitive layer coating solution, and this photosensitive layer coating solution is dip coated. The photosensitive layer 14 can be formed by coating on the intermediate layer 18 by, for example.

  The weight ratio (B ′ / A ′) of the weight (B ′) of the binder resin to the weight (A ′) of the charge transport material in the photosensitive layer 14 is the weight of the charge transport material in the charge transport layer 16 of the first embodiment. Like the weight ratio B / A of the weight (B) of the binder resin to (A), it is preferably 1.2 to 3.0. The ratio of the charge generating material in the photosensitive layer 14 is preferably 1.5 to 10% by weight.

The film thickness of the photosensitive layer 14 is preferably 5 to 100 μm, more preferably 10 to 50 μm.
If the film thickness of the photosensitive layer 14 is less than 5 μm, the charge holding ability on the surface of the photoreceptor may be lowered. If the film thickness of the photosensitive layer 14 exceeds 100 μm, the productivity may decrease.

  In the photoreceptor 3 of the third embodiment, a compound having a high charge transport ability represented by the general formula (I) according to the present invention is used as a charge transport material, whereby a binder resin is contained in the photosensitive layer 14 at a high ratio. Since it can be contained, the printing durability of the charge transport layer 16 is improved and the mechanical durability is improved without lowering the photoresponsiveness.

  The electrophotographic photoreceptor according to the present invention is not limited to the configuration of the electrophotographic photoreceptors 1, 2, and 3 of Embodiments 1 to 3 described above, and is represented by the general formula (I) according to the present invention. Other constitutions may be used as long as the compound to be contained is contained in the photosensitive layer as a charge transport material.

(Surface protective layer)
For example, a configuration in which a surface protective layer is provided on the surface of each photosensitive layer 14 in the first to third embodiments may be employed. By providing a surface protective layer on the surface of these photosensitive layers, the mechanical durability of the photoreceptor can be further improved.
For the surface protective layer, for example, a layer made of a resin, an inorganic filler-containing resin, an inorganic oxide, or the like is used.

Embodiment 4
[Image forming apparatus]
The image forming apparatus of the present invention includes the electrophotographic photosensitive member according to the present invention.
As described above, an electrophotographic photosensitive member having a high charging potential, high sensitivity, sufficient photoresponsiveness, excellent durability, and characteristics do not deteriorate even when used in a low temperature environment or in a high-speed process. Therefore, a highly reliable image forming apparatus capable of providing high-quality images under various environments is provided.

  The image forming apparatus of the present invention can be various printers, copiers, facsimiles, multifunction peripherals, etc. using an electrophotographic process regardless of monochrome or color.

Embodiments of an image forming apparatus including an electrophotographic photosensitive member according to the present invention will be described below. The image forming apparatus according to the present invention is not limited to the following description.
FIG. 4 is an arrangement side view showing a simplified configuration of an image forming apparatus 100 as an embodiment of the image forming apparatus according to the present invention. An image forming apparatus 100 shown in FIG. 4 mounts a photoreceptor 1 that is a first embodiment of the electrophotographic photoreceptor according to the present invention. Hereinafter, the configuration and image forming operation of the image forming apparatus 100 will be described with reference to FIG.

  The image forming apparatus 100 includes a photoconductor 1 that is rotatably supported by an apparatus main body (not shown), and a drive unit (not shown) that rotates the photoconductor 1 around a rotation axis 44 in the direction of an arrow 41. The drive means includes, for example, a motor as a power source, and rotates the photosensitive member 1 at a predetermined peripheral speed Vp by transmitting the power from the motor to a support member constituting the core of the photosensitive member 1 via a gear (not shown). Driven (hereinafter, this peripheral speed Vp is also referred to as a rotational peripheral speed Vp).

  Around the photosensitive member 1, a charger 32, an exposure unit 30, a developing device 33, a transfer device 34, and a cleaner 36 are downstream from the upstream side in the rotation direction of the photosensitive member 1 indicated by an arrow 41. In this order towards the side.

The charger 32 is a charging unit that charges the surface 43 of the photoreceptor 1 to a predetermined potential.
In FIG. 4, the charger 32 is shown as a contact-type charging unit such as a charging roller. However, the charger 32 is not limited to this and is a non-contact type charging unit (for example, a scorotron charger) such as a corona discharger. May be.

  The exposure unit 30 includes, for example, a semiconductor laser as a light source, and exposes the charged surface 43 of the photosensitive member 1 with light 31 such as a laser beam output according to image information from the light source. An electrostatic latent image corresponding to image information is formed on the surface 43 of the substrate.

  The developing device 33 is a developing unit that develops the electrostatic latent image formed on the surface 43 of the photoreceptor 1 with a developer (for example, toner) to form a visible toner image, and faces the photoreceptor 1. Provided. The developing device 33 includes, for example, a developing roller 33a that supplies a developer to the surface 43 of the photoreceptor 1, and supports the developing roller 33a so that the developing roller 33a can rotate around a rotation axis parallel to the rotation axis 44 of the photoreceptor 1 and the inside thereof. And a casing 33b for accommodating the developer in the space.

  The transfer unit 34 is a transfer unit that transfers the toner image formed on the surface 43 of the photoreceptor 1 from the surface 43 of the photoreceptor 1 onto the recording paper 51 that is a transfer material. In FIG. 4, the transfer unit 34 is a non-contact type transfer unit that includes a charging unit such as a corona discharger and transfers a toner image onto the recording paper 51 by applying a charge having a polarity opposite to that of the toner to the recording paper 51. is there. However, the transfer unit 34 may be a contact-type transfer unit that performs transfer using a pressing force. As the contact-type transfer means, for example, a transfer roller is provided, and the transfer roller is pressed against the photosensitive member 1 from the opposite side of the contact surface of the recording paper 51 that is in contact with the surface 43 of the photosensitive member 1. For example, a toner image can be transferred onto the recording paper 51 by applying a voltage to the transfer roller while the photosensitive member 1 and the recording paper 51 are in pressure contact with each other.

  The cleaner 36 is a cleaning unit that cleans the surface of the photoreceptor 1 after image transfer. For example, the cleaner 36 is pressed against the surface 43 of the photoconductor, and is removed by the cleaning blade 36a that removes toner remaining on the surface 43 of the photoconductor 1 after the transfer operation by the transfer unit 34 from the surface 43. A recovery casing 36b for storing the developer.

  The cleaner 36 is provided together with a static elimination lamp (not shown). The static eliminator is a means for removing the charges accumulated on the surface of the photoreceptor 1. The static eliminator is, for example, a static elimination lamp.

  In the direction in which the recording paper 51 is conveyed after passing between the photoreceptor 1 and the transfer device 34, a fixing device 35 is provided as a fixing means for fixing the transferred toner image. The fixing device 35 includes, for example, a heating roller 35a having a heating unit (not shown), and a pressure roller 35b that is provided to face the heating roller 35a and that is pressed by the heating roller 35a to form a contact portion.

Hereinafter, an image forming operation by the image forming apparatus 100 will be described.
First, in response to an instruction from a control unit (not shown), the photosensitive member 1 is rotationally driven in the direction of an arrow 41 by a driving unit, and is upstream of the image forming point of light 31 from the exposure unit 30 in the rotational direction of the photosensitive member 1. The surface 43 is uniformly charged to a predetermined positive or negative potential by the charger 32 provided on the side.

Next, in response to an instruction from the control unit, light 31 is irradiated from the exposure unit 30 to the charged surface 43 of the photoreceptor 1. The light 31 from the light source is repeatedly scanned in the longitudinal direction of the photoreceptor 1 which is the main scanning direction based on the image information. By repeatedly scanning the light 31 from the light source based on the image information while rotating the photoconductor 1, the surface 43 of the photoconductor 1 can be exposed according to the image information. By this exposure, the surface charge of the portion irradiated with the light 31 is reduced, and a difference occurs between the surface potential of the portion irradiated with the light 31 and the surface potential of the portion not irradiated with the light 31. An electrostatic latent image is formed on the surface 43.
In synchronism with the exposure of the photoreceptor 1, the recording paper 51 is supplied to the transfer position between the transfer device 34 and the photoreceptor 1 from the direction of the arrow 42 by the conveying means.

  Next, toner is applied from the developing roller 33a of the developing device 33 provided downstream of the image forming point of the light 31 from the light source to the surface 43 of the photosensitive member 1 on which the electrostatic latent image is formed. Is supplied. As a result, the electrostatic latent image is developed and a visible toner image is formed on the surface 43 of the photoreceptor 1. When the recording paper 51 is supplied between the photoconductor 1 and the transfer device 34, the transfer device 34 gives a charge having a polarity opposite to that of the toner to the recording paper 51, thereby forming the surface 43 of the photoconductor 1. The toner image is transferred onto the recording paper 51.

  The recording paper 51 onto which the toner image has been transferred is conveyed to the fixing device 35 by the conveying means, and is heated and pressed when passing through the contact portion between the heating roller 35a and the pressure roller 35b of the fixing device 35. As a result, the toner image on the recording paper 51 is fixed on the recording paper 51 and becomes a robust image. The recording paper 51 on which the image is formed in this way is discharged to the outside of the image forming apparatus 100 by the conveying means.

  On the other hand, after the toner image is transferred to the recording paper 51, the photosensitive member 1 that further rotates in the direction of the arrow 41 is scraped and cleaned by the cleaning blade 36 a provided on the cleaner 36. The charge 43 is removed from the surface 43 of the photoreceptor 1 from which the toner has been removed in this manner by the light from the static elimination lamp, and thereby the electrostatic latent image on the surface 43 of the photoreceptor 1 disappears. Thereafter, the photosensitive member 1 is further rotated and a series of operations starting from charging of the photosensitive member 1 is repeated. As described above, images are continuously formed.

  As described above, the photoreceptor 1 provided in the image forming apparatus 100 contains the compound according to the present invention represented by the general formula (I) in the photosensitive layer 14 as a charge transport material. Excellent electrical characteristics such as photoresponsiveness, electrical and mechanical durability, and environmental stability. Therefore, a highly reliable image forming apparatus 100 capable of stably forming a high-quality image over a long period of time in various environments is realized.

In addition, even when the photoreceptor 1 is used in a high-speed electrophotographic process, the image forming apparatus 100 can increase the image forming speed because the image quality does not deteriorate. For example, the photosensitive member 1 having a diameter of 30 mm and a longitudinal length of 340 mm is used, the rotational peripheral speed Vp of the photosensitive member 1 is set to about 100 to 140 mm per second, and an electrophotographic process is performed at a high speed. High-quality images can be provided even when images are formed at a high image forming speed of about 25 A4 sheets / minute as defined in JIS P0138.
The image forming apparatus of the present invention is not limited to the above-described configuration described with reference to FIG. 4, and may have another configuration as long as the photoconductor of the present invention is used.

のトリアリールアミンダイマー化合物２５．８ｇ（１.０モル当量；高砂香料工業株式会社製）を徐々に加えた。その後、徐々に加熱して反応溶液の温度を８０℃まで昇温させ、８０〜９０℃を保つように加熱しながら６時間攪拌して反応させた。反応終了後、この反応溶液を放冷し、冷却した４規定（４Ｎ）の水酸化ナトリウム水溶液１Ｌ中に徐々に加え、沈殿を生じさせた。生じた沈殿をろ取し、充分に水洗した後、エタノールと酢酸エチルとの混合溶剤で再結晶を行うことによって、黄色粉末状化合物３５．５ｇ（収率＝６２％）を得た。 EXAMPLES Hereinafter, although a manufacture example, an Example, and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited at all by these.
Production Example 1
Production of Compound 5 In 300 mL of anhydrous N, N-dimethylformamide (DMF), 16.9 g (2.2 molar equivalents) of phosphorus oxychloride was gradually added under ice cooling, and the mixture was stirred for about 30 minutes. Prepared. In this solution, the following structural formula (VI):

Of triarylamine dimer compound (25.8 g, 1.0 molar equivalent; manufactured by Takasago International Corporation) was gradually added. Thereafter, the reaction solution was gradually heated to raise the temperature of the reaction solution to 80 ° C. and stirred for 6 hours while reacting to maintain 80 to 90 ° C. for reaction. After completion of the reaction, the reaction solution was allowed to cool and gradually added to 1 L of a cooled 4N (4N) aqueous sodium hydroxide solution to cause precipitation. The resulting precipitate was collected by filtration, sufficiently washed with water, and then recrystallized with a mixed solvent of ethanol and ethyl acetate to obtain 35.5 g (yield = 62%) of a yellow powdery compound.

で示されるアルデヒド中間体（分子量の計算値：５７２.２５）の分子イオン［Ｍ］⁺に相当するピークが５７２.２に観測されたことから、得られた化合物は上記構造式（ＶＩＩ）で示されるアルデヒド中間体であることが判った。また、ＬＣ−ＭＳの分析結果から、得られたエナミン−アルデヒ中間体の純度は９９.５％であることが判った。 As a result of analyzing the obtained compound by LC-MS, the following structural formula (VII):

Since a peak corresponding to the molecular ion [M] ⁺ of the aldehyde intermediate represented by the formula (calculated molecular weight: 572.25) was observed at 572.2, the obtained compound was represented by the above structural formula (VII). It was found to be the indicated aldehyde intermediate. Further, from the analysis result of LC-MS, it was found that the purity of the obtained enamine-aldehyde intermediate was 99.5%.

で表されるウィッティヒ試薬１１．４ｇ（２.２モル当量）とを加えて溶解させた後、０℃に冷却しながら、その溶液にカリウムｔ−ブトキシド５．１６ｇ（２.３モル当量）を徐々に加えた。 Subsequently, 11.5 g (1.0 molar equivalent) of the aldehyde obtained above in 150 mL of anhydrous DMF and the following formula (VIII):

11.4 g (2.2 molar equivalents) of the Wittig reagent represented by the following formula was added and dissolved, and then cooled to 0 ° C., 5.16 g (2.3 molar equivalents) of potassium t-butoxide was added to the solution. Gradually added.

  Thereafter, the reaction solution was stirred at room temperature for 1 hour, then heated to 40 ° C., and stirred for 7 hours while being heated to maintain 40 ° C. for reaction. After allowing the reaction solution to cool, the reaction solution was poured into excess methanol. The precipitate was collected by filtration and dissolved in toluene to give a toluene solution. The toluene solution was transferred to a separatory funnel and 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 12.5 g (yield = 80%) of yellow crystals.

As a result of analyzing the obtained compound by LC-MS, a peak corresponding to the molecular ion [M] ⁺ was observed at 780.3. Therefore, the obtained compound was compound 5 (calculated molecular weight: 780.37). ). Further, from the analysis result of LC-MS, it was found that the purity of the obtained compound was 99.5%.

Production Example 2
By synthesizing in the same manner as in Production Example 1, compound 9 was obtained from the corresponding raw material through the enamine compound and enamine-aldehyde intermediate. The yield of the compound, the purity of the final product measured by LC-MS, and the molecular ion [M] ⁺ are shown in Table 2 below.

Production Example 3
By synthesizing in the same manner as in Production Example 1, compound 15 was obtained from the corresponding raw material through the enamine compound and enamine-aldehyde intermediate. The yield of the compound, the purity of the final product measured by LC-MS, and the molecular ion [M] ⁺ are shown in Table 2 below.

Production Example 4
By synthesizing in the same manner as in Production Example 1, compound 16 was obtained from the corresponding raw material through the enamine compound and enamine-aldehyde intermediate. The yield of the compound, the purity of the final product measured by LC-MS, and the molecular ion [M] ⁺ are shown in Table 2 below.

Production Example 5
By synthesizing in the same manner as in Production Example 1, compound 17 was obtained from the corresponding raw material through the enamine compound and enamine-aldehyde intermediate. The yield of the compound, the purity of the final product measured by LC-MS, and the molecular ion [M] ⁺ are shown in Table 2 below.

Production Example 6
By synthesizing in the same manner as in Production Example 1, compound 18 was obtained from the corresponding raw material through the enamine compound and enamine-aldehyde intermediate. The yield of the compound, the purity of the final product measured by LC-MS, and the molecular ion [M] ⁺ are shown in Table 2 below.

Production Example 7
By synthesizing in the same manner as in Production Example 1, compound 25 was obtained from the corresponding raw material through the enamine compound and enamine-aldehyde intermediate. The yield of each compound, the purity of the final product and the molecular ion [M] ⁺ measured by LC-MS are shown in Table 2 below.

Production Example 8
By synthesizing in the same manner as in Production Example 1, compound 26 was obtained from the corresponding raw material through the enamine compound and enamine-aldehyde intermediate. The yield of each compound, the purity of the final product and the molecular ion [M] ⁺ measured by LC-MS are shown in Table 2 below.

Production Example 9
By synthesizing in the same manner as in Production Example 1, compound 35 was obtained from the corresponding raw material through the enamine compound and enamine-aldehyde intermediate. The yield of each compound, the purity of the final product and the molecular ion [M] ⁺ measured by LC-MS are shown in Table 2 below.

Production Example 10
By synthesizing in the same manner as in Production Example 1, compound 36 was obtained from the corresponding raw material through the enamine compound and enamine-aldehyde intermediate. The yield of each compound, the purity of the final product and the molecular ion [M] ⁺ measured by LC-MS are shown in Table 2 below.

Measured value and theoretical value of molecular ion [M] ⁺ in LC-MS measurement of compounds 5, 9, 15, 16, 17, 18, 25, 26, 35 and 36 obtained in Production Examples 1 to 10 above. The structures and yields of these compounds are shown in the table below.

Example 1
9 parts by weight 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 ), copolymer nylon resin (Toray Industries, Inc.) After adding 9 parts by weight of a commercial product (CM8000) to a mixed solvent of 41 parts by weight of 1,3-dioxolane and 41 parts by weight of methanol, the mixture was dispersed for 8 hours using a paint shaker, and an intermediate layer coating solution (100 g) ) Was prepared. The intermediate layer coating solution is filled in a coating tank, and an aluminum cylindrical conductive support having a diameter of 30 mm and a longitudinal length of 357 mm is immersed in the coating layer, and then pulled and dried to obtain a middle thickness of 1.0 μm. A layer was formed on the conductive support.

  Next, as a charge generation material, a crystal having a diffraction peak at least at a Bragg angle 2θ (error: 2θ ± 0.2 °) 27.2 ° in an X-ray diffraction spectrum for Cu-Kα characteristic X-ray (wavelength: 1.54Å). 2 parts by weight of oxotitanium phthalocyanine having a structure, 1 part by weight of polyvinyl butyral resin (manufactured by Sekisui Chemical Co., Ltd .: ESREC BM-S) and 97 parts by weight of methyl ethyl ketone are mixed and dispersed by a paint shaker. A generation layer coating solution (100 g) was prepared. This charge generation layer coating solution was applied onto the intermediate layer by the same dip coating method as that for the previously formed intermediate layer, and dried to form a charge generation layer having a thickness of 0.4 μm.

Next, 10 parts by weight of the compound 5 shown in Table 1 as a charge transport material, 20 parts by weight of a polycarbonate resin (Mitsubishi Engineering Plastics Co., Ltd .: Iupilon Z400) as a binder resin, and 2,6-di-t-butyl A coating solution for charge transport layer is prepared by dissolving 1 part by weight of -4-methylphenol and 0.004 part by weight of dimethylpolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd .: KF-96) in 110 parts by weight of tetrahydrofuran (THF). (100 g) was prepared. The charge transport layer coating solution is applied onto the charge generation layer formed earlier by the same dip coating method as that of the intermediate layer formed earlier, and then dried at a temperature of 110 ° C. for 1 hour to have a film thickness of 25 μm. A charge transport layer was formed.
As described above, the electrophotographic photosensitive member of Example 1 was produced.

Example 2
An electrophotographic photoreceptor of Example 2 was produced in the same manner as Example 1 except that Compound 9 shown in Table 2 was used instead of Compound 1 as the charge transport material.

Example 3
An electrophotographic photosensitive member of Example 3 was produced in the same manner as Example 1 except that Compound 15 shown in Table 2 was used instead of Compound 1 as the charge transport material.

Example 4
An electrophotographic photoreceptor of Example 4 was produced in the same manner as in Example 1 except that Compound 16 shown in Table 2 was used instead of Compound 1 as the charge transport material.

Example 5
An electrophotographic photoreceptor of Example 5 was produced in the same manner as Example 1 except that Compound 17 shown in Table 2 was used instead of Compound 1 as the charge transport material.

Example 6
An electrophotographic photosensitive member of Example 6 was produced in exactly the same manner as in Example 1 except that Compound 18 shown in Table 2 was used instead of Compound 1 as the charge transport material.

Example 7
An electrophotographic photoreceptor of Example 7 was produced in the same manner as in Example 1 except that Compound 25 shown in Table 2 was used instead of Compound 1 as the charge transport material.

Example 8
An electrophotographic photoreceptor of Example 8 was produced in the same manner as in Example 1 except that Compound 26 shown in Table 2 was used instead of Compound 1 as the charge transport material.

Example 9
An electrophotographic photoreceptor of Example 9 was produced in the same manner as in Example 1 except that Compound 35 shown in Table 2 was used instead of Compound 1 as the charge transport material.

Example 10
An electrophotographic photoreceptor of Example 10 was produced in the same manner as in Example 1 except that Compound 36 shown in Table 2 was used instead of Compound 1 as the charge transport material.

で表される化合物Ａ（化合物５において、前記一般式（Ｉ）におけるＲ¹に相当するｏ−メチル基がない構造）を用いる以外は、実施例１と全く同様にして、比較例１の電子写真感光体を作製した。 Comparative Example 1
As a charge transport material, instead of the compound 5 of Example 1, the following structural formula (A):

In the same manner as in Example 1, except that the compound A represented by the formula (a compound 5 having no o-methyl group corresponding to R ¹ in the general formula (I)) is used, the electron of Comparative Example 1 is used. A photographic photoreceptor was prepared.

で表される化合物Ｂ（化合物２５において、前記一般式（Ｉ）におけるＲ¹に相当するｏ−メチル基がない構造）を用いる以外は、実施例７と全く同様にして、比較例２の電子写真感光体を作製した。 Comparative Example 2
As a charge transport material, instead of the compound 25 of Example 7, the following structural formula (B):

In the same manner as in Example 7, except that the compound B represented by the formula (in the compound 25, a structure having no o-methyl group corresponding to R ¹ in the general formula (I)) is used, the electron of Comparative Example 2 is used. A photographic photoreceptor was prepared.

で表される化合物Ｃ（化合物１７において、前記一般式（Ｉ）におけるＲ¹に相当するｏ−メチル基がない構造）を用いる以外は、実施例５と全く同様にして、比較例３の電子写真感光体を作製した。 Comparative Example 3
As a charge transport material, instead of the compound 17 of Example 5, the following structural formula (C):

In the same manner as in Example 5 except that the compound C represented by the formula (a structure having no o-methyl group corresponding to R ¹ in the general formula (I) in the compound 17) is used, the electron of Comparative Example 3 is used. A photographic photoreceptor was prepared.

で表される化合物Ｄ（化合物２６において、前記一般式（Ｉ）におけるＲ¹に相当するｏ−メチル基がない構造）を用いる以外は、実施例８と全く同様にして、比較例４の電子写真感光体を作製した。 Comparative Example 4
As a charge transport material, instead of the compound 26 of Example 8, the following structural formula (D):

In the same manner as in Example 8 except that the compound D represented by the formula (a structure having no o-methyl group corresponding to R ¹ in the general formula (I) in the compound 26) is used, the electron of Comparative Example 4 is used. A photographic photoreceptor was prepared.

で表される化合物Ｅ（化合物５において、ｐ−メトキシスチレン基がない構造）を用いる以外は、実施例１と全く同様にして、比較例５の電子写真感光体を作製した。 Comparative Example 5
As a charge transport material, instead of the compound 5 of Example 1, the following structural formula (E):

An electrophotographic photosensitive member of Comparative Example 5 was produced in the same manner as in Example 1 except that Compound E represented by the following formula (Compound 5 having no p-methoxystyrene group) was used.

で表される化合物Ｆ（化合物１５における４−（ｏ,ｐ−ジメチルフェニル）−１,３−ブタジエニル基をメチル基で置き換えた構造）を用いる以外は、実施例３と全く同様にして、比較例６の電子写真感光体を作製した。 Comparative Example 6
As a charge transport material, instead of the compound 15 of Example 3, the following structural formula (F):

In the same manner as in Example 3, except that the compound F (structure in which 4- (o, p-dimethylphenyl) -1,3-butadienyl group in Compound 15 is replaced with a methyl group) represented by The electrophotographic photoreceptor of Example 6 was produced.

で表される化合物Ｇを用いる以外は、実施例６と全く同様にして、比較例７の電子写真感光体を作製した。 Comparative Example 7
As a charge transport material, instead of the compound 18 of Example 6, the following structural formula (G):

An electrophotographic photosensitive member of Comparative Example 7 was produced in the same manner as in Example 6 except that Compound G represented by

で表される化合物Ｈを用いる以外は、実施例１と全く同様にして、比較例８の電子写真感光体を作製した。
以上のようにして作製した実施例１〜１０および比較例１〜８の各感光体について、以下のようにして（ａ）耐ガス性、（ｂ）耐摩耗性および（ｃ）電気特性の安定性を評価し、さらに（ｄ）感光体性能の総合判定を行なった。 Comparative Example 8
As a charge transport material, instead of the compound 5 of Example 1, the following structural formula (H):

An electrophotographic photosensitive member of Comparative Example 8 was produced in the same manner as in Example 1 except that Compound H represented by
For each of the photoreceptors of Examples 1 to 10 and Comparative Examples 1 to 8 produced as described above, (a) gas resistance, (b) wear resistance, and (c) stability of electrical characteristics are as follows. The properties were evaluated, and (d) a comprehensive determination of the photoreceptor performance was made.

(A) Gas resistance Commercial photocopier MX-3100FG (trade name, Sharp) equipped with a corona discharge charger as a charging means for each of the actual device evaluation photoconductors of Examples 1 to 10 and Comparative Examples 1 to 8. The test images of a predetermined pattern were photographed on 50,000 sheets of recording paper in a normal temperature / normal humidity (N / L) environment at a temperature of 25 ° C. and a relative humidity of 10%. The operation of the copying machine was stopped for 1 hour after the end of the 50,000 actual shots, and then a halftone image was copied on the recording paper, which was used as the first evaluation image. Next, a test image of a predetermined pattern is photographed on 50,000 sheets of recording paper again in an N / L environment at a temperature of 25 ° C. and a relative humidity of 10%, and the copying machine operates for 12 hours from the time when 50,000 sheets are photographed. Then, a halftone image was copied on the recording paper, and this was used as a second evaluation image.

  The formed first evaluation image and second evaluation image were visually observed, and the toner image was transferred from the portion of the photoconductor that was placed close to the corona discharge charger when the operation of the copying machine was stopped. The image quality of the portion of the recording paper corresponding to the portion was determined based on the degree of occurrence of image defects such as white spots and black bands, and used as an evaluation index for ozone gas resistance.

The criteria for determining the image quality are as follows.
VG: very good: no image defect occurs in any of the first evaluation image and the second evaluation image G: good: the first evaluation image and the second evaluation image Some image defects have occurred in either one or both, but are negligible. NB: not bad: some in either or both of the first evaluation image and the second evaluation image Although image defects have occurred, there is no problem in actual use. B: Bad: Many image defects have occurred in one or both of the first evaluation image and the second evaluation image. Cannot be used.

(B) Printing durability (wear resistance)
Each of the actual device evaluation photoreceptors of Examples 1 to 10 and Comparative Examples 1 to 8 was placed on a commercially available copying machine MX-3100FG (trade name, manufactured by Sharp Corporation) equipped with a corona discharge charger as a charging means for the photoreceptor. Mounted, in a normal temperature / normal humidity (N / N) environment with a temperature of 25 ° C. and a relative humidity of 50%, a test image of a predetermined pattern was actually captured on 100,000 sheets of recording paper, and the mounted photoconductor was then mounted. The film thickness d1 [μm] of the photosensitive layer was taken out, and a value (d0−d1) obtained by subtracting this value d1 from the film thickness d0 of the photosensitive layer at the time of production was obtained as a film reduction amount Δd.

The criteria for judging printing durability are as follows.
VG: very good: Δd is less than 5 μm G: good: Δd is not less than 5 μm and less than 8 μm NB: not bad: Δd is not less than 8 μm and less than 12 μm B: bad: Δd is not less than 12 μm

(C) Electrical characteristics Each of the actual apparatus evaluation photoreceptors of Examples 1 to 10 and Comparative Examples 1 to 8 is mounted on a test copying machine, and the temperature is 5 ° C. and the relative humidity is 20%. Low temperature / low humidity (L / L: The electrical characteristics are as follows in a low temperature / low humidity environment and in a high temperature / high humidity (H / H) environment with a temperature of 35 ° C and a relative humidity of 85%. evaluated. The test copier measures the surface potential of the photoconductor during the image formation process inside a commercially available photocopier MX-3100FG (trade name, manufactured by Sharp Corporation) equipped with a corona discharge charger as the photoconductor charging means. What provided the surface electrometer (brand name: CATE751, the Gentec company make) so that it could do was used. The copying machine MX-3100FG is a negatively charged image forming apparatus that performs electrophotographic process by negatively charging the surface of the photoreceptor.

  Using the test copying machine on which each photoconductor of Examples 1 to 10 and Comparative Examples 1 to 8 is mounted, the surface potential of the photoconductor immediately after the charging operation by the charger is measured as a charging potential V0 (V). Was the initial charging potential V01. Further, the surface potential of the photoconductor immediately after being exposed to the laser beam was measured as a residual potential Vr (V), and this was set as the initial residual potential Vr1.

  Next, after continuously copying a test image of a predetermined pattern onto 300,000 sheets of recording paper, the charging potential V0 and the residual potential Vr are measured in the same manner as in the initial stage, and the charging potential V02 after repeated use and the repeated potential are measured. The residual potential Vr2 after use was set. The absolute value of the difference between the initial charging potential V01 and the charging potential V02 after repeated use was determined as a charging potential change amount ΔV0 (= | V01−V02 |). Further, the absolute value of the difference between the initial residual potential Vr1 and the residual potential Vr2 after repeated use was obtained as a residual potential change amount ΔVr (= | Vr1−Vr2 |). Electrical characteristics were evaluated using the charging potential change amount ΔV0 and the residual potential change amount ΔVr as evaluation indexes.

Electrical characteristics under L / L environment Evaluation criteria for electrical characteristics under L / L environment are as follows)
VG: very good: ΔV0 is 35 V or less and ΔVr is 55 V or less and Vr1 is 100 V or less G: good: ΔV0 is 35 V or less, ΔVr is over 55 V and 80 V or less and Vr1 is 150 V or less, or ΔV0 is (Over 35V, 75V or less, ΔVr is 55V or less, and Vr1 is 150V or less)
NB: No problem in actual use (not bad): ΔV0 exceeds 35V and 75V or less and ΔVr exceeds 55V and 80V or less and Vr1 is 200V or less B: Bad (bad): ΔV0 exceeds 75V or ΔVr exceeds 80V Or Vr1 exceeds 200V.

Electrical characteristics under H / H environment Evaluation criteria for electrical characteristics under H / H environment are as follows.
VG: very good: ΔV0 is 15V or less and ΔVr is 105V or less G: good: ΔV0 is 15V or less and ΔVr exceeds 105V and 125V or less, or ΔV0 exceeds 15V and 30V or less and ΔVr is 105V or less NB: No problem in actual use (not bad): ΔV0 exceeds 15V and 30V or less and ΔVr exceeds 105V and 125V or less B: Bad (bad): ΔV0 exceeds 30V or ΔVr exceeds 125V

Comprehensive evaluation of electrical characteristics In addition, the overall evaluation of electrical characteristics was performed by combining the evaluation results in the L / L environment and the evaluation results in the H / H environment. The evaluation criteria for the comprehensive evaluation of the stability of the electrical characteristics are as follows.
VG: very good: both L / L environment and H / H environment are good G: good: either L / L environment or H / H environment is good and the other is good Or NB: Not bad in actual use (not bad): Either in the L / L environment or H / H environment, there is no problem in actual use, and the other is not bad. B: Bad: in L / L environment and H Either one or both under / H environment is defective.

(D) Comprehensive Judgment of Photoreceptor Performance A comprehensive judgment of the photoreceptor performance was made by combining the evaluation results of gas resistance and the comprehensive evaluation results of stability of printing durability and electrical characteristics. (The criteria for comprehensive judgment are as follows)
VG: very good: excellent in gas resistance, printing durability, and electrical property stability G: good: any of gas resistance, printing durability, and electrical property stability is good NB: not bad in actual use (not bad): any of gas resistance, printing durability, and stability of electric characteristics is not problematic in actual use, and the other is not bad. B: bad ): One or both of gas resistance, printing durability, and electrical property stability are poor.

The above evaluation results are shown in Table 3.

  From comparison between Examples 1 to 10 and Comparative Examples 1 to 8, the photoreceptors of Examples 1 to 10 containing the triarylamine dimer compound according to the present invention are compared to the photoreceptors of Comparative Examples 1 to 8 that do not contain. It can be seen that it is excellent in gas resistance, wear resistance and electrical properties, and exhibits good electrical properties even when used repeatedly.

By incorporating the triarylamine dimer compound according to the present invention into the photosensitive layer as a charge transport material, it is possible to provide a photoreceptor having excellent gas resistance, high sensitivity, and sufficient photoresponsiveness.
Further, even when the photoreceptor of the present invention is used in a high-speed electrophotographic process, it can provide a high-quality image due to its excellent gas resistance effect.

1, 2, 3 Electrophotographic photoreceptor 11 Conductive support 12 Charge generating material 13 Charge transporting material 14 Photosensitive layer 15 Charge generating layer 16 Charge transporting layer 17 Binder resin 18 Intermediate layer

30 Exposure means 31 Light from exposure means 32 Charging device 33 Development device 33a Development roller 33b Casing 34 Transfer device 35 Fixing device 35a Heating roller 35b Pressure roller

36 Cleaner 36a Cleaning blade 36b Recovery casing 41 Arrow 42 Arrow 43 Photosensitive member surface 44 Rotating axis 51 Recording paper 100 Image forming apparatus

Claims (9)

As a photosensitive layer, a multilayer 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 type photosensitive layer containing a charge generation material and a charge transport material Is formed on a conductive support, and the charge transport layer or the single-layer type photosensitive layer is represented by the following general formula (I):

[Where:
Ar ¹ is an aryl or heterocyclic group, and these groups may have a substituent;
Ar ² is a hydrogen atom or an alkyl, aralkyl or aryl group or a monovalent heterocyclic group, and these groups may have a substituent;
R ¹ is an alkyl group, which may have a substituent;
R ² and R ³ are the same or different from each other, and are a hydrogen atom or an alkyl group, and these groups may have a substituent;
R ⁴ and R ⁵ are the same or different from each other and are a hydrogen atom or an alkyl or alkoxy group, and these groups may have a substituent;
n is 0 or 1]
An electrophotographic photoreceptor comprising a triarylamine dimer compound represented by the formula: In the Ar ¹ , the aryl group is a phenyl, naphthyl, tetrahydronaphthyl, biphenyl or fluorenyl group, or the heterocyclic group is a furyl, thienyl, thiazolyl, benzofuryl, phenylbenzofuryl or carbazolyl group, and these groups May be substituted with one or more halogen atoms or a linear or branched C ₁ -C ₄ alkyl or alkoxy group, or may be substituted with a phenoxy or phenylthio group;
In Ar ² , the alkyl group is methyl, ethyl, n-propyl, isopropyl, t-butyl, cyclohexyl or cyclopentyl group, the aralkyl group is benzyl or phenethyl group, or the aryl group is phenyl, naphthyl, tetrahydro A naphthyl, biphenyl or fluorenyl group, or the monovalent heterocyclic group is a furyl, thienyl, thiazoyl, benzofuryl, benzothiophenyl or benzothiazoyl group, these groups comprising one or more halogen atoms or or it may be substituted by straight-chain or branched C ₁ -C ₄ alkyl or alkoxy group, or a phenyl, phenoxy, may be substituted by phenylthio or naphthyl group;
The alkyl group in R ¹ is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group, and these groups may be substituted with a halogen atom;
The alkyl group in R ² and R ³ is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group, and these groups may be substituted with a hydrogen atom or a halogen atom;
The alkyl group in R ⁴ and R ⁵ is methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group, or the alkoxy group is methoxy, ethoxy, n-propoxy, isopropoxy, n- 2. The electrophotographic photoreceptor according to claim 1, which is a butoxy or t-butoxy group, and these groups may be substituted with a hydrogen atom or a halogen atom. In the Ar ¹ , the aryl group is a phenyl, naphthyl, tetrahydronaphthyl, or biphenyl group, or the heterocyclic group is a furyl, thienyl, thiazolyl, or benzofuryl group, and these groups are one or more halogen atoms or linear Optionally substituted with a linear or branched C ₁ -C ₄ alkyl, alkoxy or alkylene group;
In the Ar ² , the alkyl group is a methyl, ethyl, n-propyl, isopropyl or t-butyl group, or the aryl group is a phenyl, naphthyl or biphenyl group, or the monovalent heterocyclic group The groups are furyl, thienyl or thiazolyl groups, which groups are substituted by one or more halogen atoms or linear or branched C ₁ -C ₄ alkyl or alkoxy groups, phenyl, phenoxy or naphthyl groups May be;
The alkyl group in R ¹ is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group;
The alkyl group in R ² and R ³ is a methyl, ethyl, n-propyl, isopropyl, n-butyl or t-butyl group;
The electrophotographic photosensitive member according to claim 1 or 2, wherein the alkyl group in R ⁴ and R ⁵ is a methyl or ethyl group, or the alkoxy group is a methoxy or ethoxy group. Ar ¹ is a phenyl, p-tolyl, m-tolyl, 1-naphthyl, 2-naphthyl or 5,6,7,8-tetrahydro-1-naphthyl group;
Ar ² is a hydrogen atom or an isopropyl, phenyl, p-tolyl, benzyl or thienyl group;
R ¹ is a methyl, ethyl or isopropyl group;
R ² and R ³ are a hydrogen atom or a methyl or ethyl group,
The electrophotographic photoreceptor according to claim 1, wherein R ⁴ and R ⁵ are a hydrogen atom or an o-methyl, p-methyl, or p-methoxy group.   2. The charge generating material is oxotitanium phthalocyanine having a diffraction peak at a Bragg angle (2θ ± 0.2 °) of at least 27.2 ° in Cu-Kα characteristic X-ray diffraction (wavelength: 1.54Å). The electrophotographic photosensitive member according to any one of -4.   6. The laminated photosensitive layer according to claim 1, wherein the photosensitive layer is a laminated photosensitive layer in which a charge generation layer containing the charge generation material and a charge transport layer containing the charge transport material are laminated in this order. The electrophotographic photoreceptor described in 1.   The electrophotographic photosensitive member according to claim 1, further comprising an intermediate layer between the conductive support and the photosensitive layer.   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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