JP2009020204A - Electrophotographic photoreceptor and image forming device incorporating it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly durable electrophotographic photoreceptor which is excellent in mechanical and electrical durability without forming abnormal images such as blurred images even when used repeatedly over a long term and can output stabilized images for a long term, and to provide an image forming device incorporating it. <P>SOLUTION: The electrophotographic photoreceptor is formed by stacking a charge generating layer at least containing charge generating materials and a charge carrier layer containing charge carrier materials in this order on a conductive support consisting of conductive materials. Its outermost surface layer contains filler particles and a specific diamine compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member used for electrophotographic image formation and an image forming apparatus including the same.

2. Description of the Related Art An electrophotographic image forming apparatus (hereinafter also referred to as “electrophotographic apparatus”) that forms an image using electrophotographic technology is widely used in copying machines, printers, facsimile apparatuses, and the like.
In an electrophotographic apparatus, an image is formed through the following electrophotographic process.

  First, a photosensitive layer of an electrophotographic photosensitive member (hereinafter also referred to as “photosensitive member”) provided in the apparatus is uniformly charged to a predetermined potential by a charger, and then irradiated by an exposure unit according to image information. An electrostatic latent image is formed by exposure to light such as light. The developer is supplied from the developing means to the formed electrostatic latent image, and the electrostatic latent image is developed by attaching colored fine particles called toner, which is a component of the developer, to the surface of the photoreceptor. It is visualized as a toner image. The formed toner image is transferred from the surface of the photoreceptor onto a transfer material such as recording paper by a transfer unit, and fixed by a fixing unit to form a desired image.

  During the transfer operation by the transfer means, not all the toner on the surface of the photoconductor is transferred to the recording paper and transferred, but a part of the toner remains on the surface of the photoconductor. Further, the paper dust of the recording paper that comes into contact with the photoconductor during transfer may remain attached to the surface of the photoconductor. Such foreign matters such as residual toner and adhering paper dust on the surface of the photosensitive member adversely affect the quality of the formed image and are removed by the cleaning device.

  In recent years, cleaner-less technology has advanced, and residual toner is collected by a so-called developing and cleaning system, which is a cleaning function added to the developing means without having an independent cleaning means. After the surface of the photoreceptor is cleaned in this manner, the surface of the photosensitive layer is neutralized by a static eliminator or the like, and the electrostatic latent image disappears.

A photoreceptor used in such an electrophotographic process is configured by laminating a photosensitive layer containing a photoconductive material on a conductive substrate made of a conductive material.
Conventionally, a photoreceptor using an inorganic photoconductive material (hereinafter also referred to as “inorganic photoreceptor”) has been used as the photoreceptor. Representative inorganic photoconductors include a selenium photoconductor using a layer made of amorphous selenium (a-Se), amorphous selenium arsenide (a-AsSe), etc. as a photosensitive layer, zinc oxide (ZnO), sulfide. Zinc oxide-based photoreceptor, cadmium sulfide-based photoreceptor, and amorphous silicon (a-Si) layer used as a photosensitive layer in which cadmium (CdS) is dispersed in a resin together with a sensitizer such as a dye is used as a photosensitive layer. There is an amorphous silicon photoconductor (a-Si photoconductor) used.

However, inorganic photoreceptors have the following drawbacks.
Selenium photoreceptors and cadmium sulfide photoreceptors have problems with heat resistance and storage stability. Since selenium and cadmium are toxic to the human body and the environment, photoreceptors using these must be recovered after use and disposed of properly.

Zinc oxide photoreceptors have the disadvantages of low sensitivity and low durability, and are rarely used today.
In addition, an a-Si photosensitive member which is attracting attention as a non-polluting inorganic photosensitive member has advantages such as high sensitivity and high durability, but is manufactured using a plasma chemical vapor deposition method. It is difficult to form a uniform film, and image defects are likely to occur. In addition, the a-Si photosensitive member has disadvantages that productivity is low and manufacturing cost is high.

As described above, since there are many disadvantages of inorganic photoreceptors, development of photoconductive materials used for photoreceptors has progressed, and organic photoconductors have been used instead of inorganic photoconductive materials that have been used conventionally. In other words, an organic photoconductor (Organic Photoconductor; OPC) is frequently used.
Electrophotographic photoreceptors using organic photoconductive materials (hereinafter also referred to as “organic photoreceptors”) have some problems in sensitivity, durability, environmental stability, etc., but are toxic, manufacturing costs and materials. It has many advantages over inorganic photoreceptors in terms of design freedom and the like.
The organic photoreceptor also has an advantage that the photosensitive layer can be formed by an easy and inexpensive method typified by a dip coating method.

As described above, organic photoreceptors have many advantages, and thus gradually become the mainstream of photoreceptors.
Also, due to recent research and development, the sensitivity and durability of organic photoreceptors have been improved, and organic photoreceptors are now being used as photoreceptors except in special cases.

In particular, the performance of organic photoreceptors has been remarkably improved by the development of function-separated photoreceptors in which a charge generation function and a charge transport function are assigned to different substances.
That is, the function-separated type photoconductor has the advantage that a photoconductor having an arbitrary characteristic can be relatively easily produced in addition to the above-mentioned advantages of the organic photoconductor. Also have.

There are two types of function-separated type photoreceptors: a laminated type and a single layer type.
In the laminated type function separation type photoconductor, a laminated type constituted by laminating a charge generation layer containing a charge generation material responsible for a charge generation function and a charge transport layer containing a charge transport material responsible for a charge transport function. The photosensitive layer is provided.
The charge generation layer and the charge transport layer are usually formed in a form in which the charge generation material and the charge transport material are each dispersed in a binder resin as a binder.
On the other hand, in a single-layer type function dispersion type photoreceptor, a single-layer type photosensitive layer in which a charge generation material and a charge transport material are dispersed together in a binder resin is provided.

In the electrophotographic apparatus, the above-described charging, exposure, development, transfer, cleaning, and charge removal operations are repeatedly performed on the photosensitive member under various environments. Therefore, in addition to high sensitivity and excellent photoresponsiveness, the photoreceptor is required to have excellent environmental stability, electrical stability, and durability (press life) against mechanical external force.
That is, high printing durability is required in which the surface layer of the photoreceptor is not easily worn by rubbing with a cleaning member or the like.

As an effort to improve printing durability, a technique for providing a protective layer on the outermost surface layer of the photoreceptor (see, for example, JP-A-57-30846 (Patent Document 1)) and imparting lubricity to the protective layer Technology (see, for example, Japanese Patent Laid-Open No. 64-23259 (Patent Document 2)), technology for curing the protective layer (see, for example, Japanese Patent Laid-Open No. 61-72256 (Patent Document 3)), and the protective layer A technique (for example, see JP-A-1-172970 (Patent Document 4)) in which filler particles are contained in the toner is known.
These protective layers are basically desired to be made as thin as possible from the viewpoint of not impairing the basic function of the photosensitive layer.

However, the provision of the protective layer causes the following various problems.
For example, when an interface is formed between the photosensitive layer and the protective layer and the components of each layer are separated from each other (discontinuous layer structure), the protective layer may peel off due to long-term use. . In addition, the exposure portion potential may increase due to repeated use over a long period of time.
On the contrary, when the photosensitive layer and the protective layer are continuously layered, that is, when the photosensitive layer is dissolved by the protective layer coating solution to be subsequently applied, the image characteristics of the photosensitive layer may deteriorate depending on the dissolution state.

  Among the above-mentioned prior arts, the technique of incorporating filler particles adds a new influence factor on the photoreceptor characteristics such as particle dispersibility control. That is, characteristics are not defined only by the amount of simple filler particles added. For example, JP-A-1-205171 (Patent Document 5) discloses that the printing durability is improved by addition of about 0.1 to 10% by weight with respect to the total solid content of the protective layer. However, it is easily estimated that the image characteristics / electrical characteristics / printing durability of the photoconductor as the photoconductor drum differ depending on the dispersion state of the filler particles. In addition, when the dielectric constant of the protective layer becomes nonuniform, image thickening and toner scattering may occur at the edge when a black solid image is output, and the dispersion state of the filler particles inside the protective layer may be It can be seen that this greatly affects the characteristics.

  In the function-separated type photoconductor, if the printing durability (abrasion resistance) can be imparted to the outermost surface, the production process does not include an extra step, so compared with the case where a protective layer is imparted. There are significant cost benefits. Further, it is possible to avoid the above-described adverse effects caused by providing the photosensitive layer and the protective layer in a stacked manner.

However, on the other hand, it is necessary to consider new issues on the system.
For example, when filler particles are added to the outermost surface layer of a multilayer photoconductor without providing a protective layer to improve printing durability, charge generation, which is thought to be due to the interaction between the filler particles and the charge generation layer Image defects may occur due to non-uniformity of the layer near the interface between the layer and the charge transport layer.
In addition, a trap over the entire charge transport layer of several tens of μm occurs between the filler particles and the polymer bulk (binder resin) contained in the photosensitive layer, and there is a risk that the residual potential of the exposed area may increase, which is a protective layer. Compared with the case where filler particles are added by providing the material, the size becomes extremely large.

  Furthermore, when filler particles are added to the outermost surface layer of the photoconductor for improving printing durability, the photoconductor is easily affected by an oxidizing gas such as ozone or nitrogen oxide released from the corona discharge charger. As a result, especially in a high-temperature and high-humidity environment, the charged potential decreases, the residual potential increases, the surface resistance decreases, the resolving power decreases, the image quality on the output image decreases significantly, and the life of the photosensitive member is reduced. Becomes shorter.

For such a phenomenon, the gas around the corona charger is efficiently exhausted and replaced, and measures to avoid direct gas influence on the photoconductor are incorporated, and the outermost surface layer containing filler particles is prevented from oxidation. It has been proposed to add an agent or stabilizer to prevent deterioration of the photoreceptor.
However, if a small amount of an antioxidant or stabilizer is added to the outermost surface layer of the photoreceptor containing filler particles, the charged potential of the photoreceptor decreases due to repeated use over a long period of time, resulting in image deterioration. End up.

  On the contrary, when an antioxidant or a stabilizer that can withstand repeated use over a long period of time is added to the outermost surface layer of the photoreceptor, the residual potential may increase from the beginning or the film scraping may increase. For example, in Japanese Patent Application Laid-Open No. 2002-139659 (Patent Document 6), by adding a specific amount of a compound having a hindered amine structure and a hindered phenol structure to the outermost surface layer containing a filler, printing durability and gas resistance are improved. Although it is described that both have been improved, these improvements, particularly the improvement in gas resistance, are still not sufficient.

Japanese Unexamined Patent Publication No. 57-30846 Japanese Patent Laid-Open No. 64-23259 JP 61-72256 A JP-A-1-172970 JP-A-1-205171 JP 2002-139659 A

  That is, sufficient ozone resistance has not yet been achieved by such conventional techniques, 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, a new material proposal that improves ozone resistance and has no harmful effect on electrophotographic characteristics is awaited.

  Therefore, the present invention is excellent in mechanical / electric durability even for repeated use over a long period of time, and does not generate abnormal images such as image blurring, and is highly durable capable of stable image output over a long period of time. An object is to provide an electrophotographic photosensitive member and an image forming apparatus including the same.

  As a result of intensive studies on improving the printing durability and ozone resistance of a photoreceptor having a multilayer photosensitive layer, the present inventors have made the photosensitive layer contain specific filler particles and a specific diamine compound, The inventors have found that a photoconductor with significantly improved printing durability and excellent ozone resistance can be obtained, and the present invention has been completed.

Thus, according to the present invention, a stacked type in which a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material are laminated in this order on a conductive support made of a conductive material. A photosensitive member in which a photosensitive layer is laminated, and the outermost surface layer of the electrophotographic photosensitive member includes filler particles,
Formula (I):

[Where:
Ar ¹ , Ar ² , Ar ³ and Ar ⁴ are the same or different and each may have an aryl group which may have a substituent, a cycloalkyl group which may have a substituent, or a hetero which may have a substituent. A monovalent heterocyclic residue optionally having an atom-containing cycloalkyl group or a substituent;
^{Y 1, Y 2, Y 3} , Y 4, Y 5 and Y ⁶ are the same or different, have a good chain alkylene group which may have a substituent;
Z represents i) —Ar ⁵ —, ii) —Ar ⁵ —Ar ⁶ — or ii) —Ar ⁵ —W—Ar ⁶ — (wherein Ar ⁵ and Ar ⁶ are the same or different and each represents a substituent). An arylene group which may have or a divalent heterocyclic residue which may have a substituent; W is a cycloalkylidene group which may have a substituent, a chain which may have a substituent Or a branched alkylene group, an oxygen atom or a sulfur atom)
A diamine compound represented by

The filler particles have the following formula (I):
1.0 × 10 ⁻³ ≦ (df × b ³ ) / (dm × a ³ ) ≦ 2.5 × 10 ⁻² (1)
(Wherein, a means the average distance between filler particles (nm), b means the average filler particle diameter (nm), df means the density of filler particles (g / cm ³ ), Meaning the average density (g / cm ³ ) of the solid content in the outermost surface layer)
Is contained in the outermost surface layer in a dispersed state satisfying the above.
The numbering of the substituents in the chemical formulas described in the present specification includes upper left, upper right, and lower right letters, but these are the same. For example, “ ¹ Ar”, “Ar ¹ ” and “Ar ₁ ” represent the same substituent.

  According to the invention, the photosensitive member, the charging unit for charging the photosensitive member, the exposing unit for exposing the charged photosensitive member, and the electrostatic latent image formed by the exposure are developed. An image forming apparatus comprising a developing unit and a transfer unit that transfers the electrostatic latent image onto a transfer material is provided.

According to the present invention, even when used repeatedly for a long period of time, it has excellent mechanical / electrical durability and does not generate abnormal images such as image blurring, and is highly durable capable of stable image output over a long period of time. An electrophotographic photosensitive member and an image forming apparatus including the same can be provided.
That is, the photoconductor of the present invention contains filler particles in the outermost surface layer of the photoconductor in order to improve printing durability. Avoid by including the compound.
Therefore, the image forming apparatus according to the present invention can stably form a high-quality image free from image defects over a long period of time under various environments.

  The photoconductor of the present invention is a multi-layer type photoconductor in which a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material are laminated in this order on a conductive support made of a conductive material. A photoreceptor in which layers are laminated, wherein the outermost surface layer of the photoreceptor contains filler particles satisfying formula (1) and a diamine compound represented by formula (I).

Among such diamine compounds of the general formula (I), points such as chemical stability such as decomposition or alteration as a chemical substance, availability of raw materials, ease of production and high yield, and production cost A diamine compound in which Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ and Y ⁶ in the general formula (I) are chain alkylene groups, that is, the sub-formula (II)

(Wherein Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Y ⁵ , Y ⁶ and Z are as defined in formula (I); n, m, l and p are the same or different and A diamine compound in which Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ and Y ^{6 in} the general formula (I) are chain methylene groups, that is, the sub-formula ( III):

(In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ have the same meanings as those in the general formula (I)).
A diamine compound represented by is particularly preferred.

The substituents in the general formula (I), sub-formula (II) and sub-formula (III) will be described.
Examples of the aryl group that may have a substituent of Ar ¹ , Ar ² , Ar ^3, and Ar ⁴ include, for example, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and 2 to 6 carbon atoms. Examples thereof include an aryl group optionally substituted with a dialkylamino group or a halogen atom.
Specifically, phenyl group, o-tolyl group, 2,4-xylyl group, 4-methoxyphenyl group, 3-methoxy-4-methylphenyl group, t-butylphenyl group, 4-diethylaminophenyl group, 4- A chlorophenyl group, a 4-fluorophenyl group, a 1-naphthyl group, a 2-naphthyl group, etc. are mentioned. Among these, a phenyl group, an o-tolyl group, a 4-methoxyphenyl group, a 1-naphthyl group, a 2-naphthyl group Is particularly preferred.

Examples of the cycloalkyl group which may have a substituent of Ar ¹ , Ar ² , Ar ³ and Ar ⁴ include a cycloalkyl group which may be substituted with an alkyl group having 1 to 4 carbon atoms.
Specific examples include a cyclohexyl group, a cyclopentyl group, a 4,4-dimethylcyclohexyl group, and among these, a cyclohexyl group is particularly preferable.

Examples of the hetero atom-containing cycloalkyl group which may have a substituent for Ar ¹ , Ar ² , Ar ³ and Ar ⁴ include a tetrahydrofuryl group and a tetramethyltetrahydrofuryl group.

As the monovalent heterocyclic residue which may have a substituent of Ar ¹ , Ar ² , Ar ³ and Ar ⁴ , for example, a monovalent complex which may be substituted with an alkyl group having 1 to 4 carbon atoms. A ring residue is mentioned.
Specific examples include a furyl group, a 4-methylfuryl group, a benzofuryl group, and a benzothiophenyl group. Among these, a furyl group and a benzofuryl group are particularly preferable.

The chain alkylene group which may have a substituent of Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ and Y ⁶ may be substituted with, for example, an alkyl group having 1 to 4 carbon atoms. An alkylene group is mentioned.
Specific examples include a methylene group, an ethylene group, a propylene group, and a 2,2-dimethylpropylene group. Among these, a methylene group and an ethylene group are particularly preferable.

Examples of the arylene group which may have a substituent for Ar ⁵ and Ar ⁶ in Z include an arylene group which may be substituted with an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. It is done.
Specific examples include p-phenylene group, m-phenylene group, methyl-p-phenylene group, methoxy-p-phenylene group, 1,4-naphthylene group, benzoxazolen group, biphenylylene group, and the like. Among them, p-phenylene group, m-phenylene group, methyl-p-phenylene group, methoxy-p-phenylene group and 1,4-naphthylene group are preferable, and p-phenylene group and 1,4-naphthylene group are particularly preferable. .

Examples of the divalent heterocyclic residue optionally having a substituent for Ar ⁵ and Ar ⁶ in Z include a 1,4-furandiyl group, a 1,4-thiophenediyl group, and a 2,5-benzofurandyl group. 2,5-benzoxazolediyl group and N-ethylcarbazole-3,6-diyl group.

Examples of the cycloalkylidene group which may have a substituent of W in Z include a cycloalkylidene group which may be substituted with an alkyl group having 1 to 4 carbon atoms.
Specific examples include a cyclopentylidene group, a cyclohexylidene group, a 4,4-dimethylcyclohexylidenyl group, a cyclopentylidene group, and the like.

Examples of the chain or branched alkylene group which may have a substituent include an alkylene group which may be substituted with an alkyl group having 1 to 4 carbon atoms.
Specific examples include a methylene group, an ethylene group, a propylene group, and a 2,2-dimethylpropylene group. Among these, a methylene group and an ethylene group are particularly preferable.

Specific examples of the diamine compound of the present invention are shown in Table 1.
In Tables 1-1 to 1-6, substituents are represented by the following abbreviations.
-Me-: methylene group -Et-: ethylene group -Tr-: trimethylene group -Dm-: 2,2-dimethyltrimethylene group

  Among the diamine compounds of the present invention shown in Tables 1-1 to 1-6, Exemplified Compound Nos. 1, 2, 4, 8, 14, 22, 29, 38, 50, 53 and 57 are preferred. 1 and 2 are particularly preferred, and Exemplified Compound No. 1 1 is more preferable.

  The diamine compound of the present invention can be produced by the method shown in the following reaction scheme. That is, by heating the amine compound represented by the general formula (V) and the general formula (VI) and the dihalogen compound represented by the general formula (VII) in the presence of an organic amine base, the yield can be easily increased. The target product can be produced with high purity.

[Reaction formula]
(Wherein Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ , Y ⁹ and Z are as defined in formula (I); X ¹ and X ² represents a halogen atom)
Examples of the halogen atom of X ¹ and X ² in the reaction formula include a chlorine atom, a bromine atom, and an iodine atom, and among these, a chlorine atom and a bromine atom are particularly preferable.

The reaction of the above reaction formula can be carried out, for example, as follows.
The secondary amine compounds (V) and (VI) and the dihalogen compound (VII) are dissolved or dispersed in a solvent, an organic amine base is added thereto, and the mixture is heated and stirred. After completion of the reaction, the precipitate is filtered off and recrystallized in ethanol, methanol, ethyl acetate or the like alone or in a mixed solvent system, whereby the target product can be obtained easily and with high purity in high yield.

The solvent is not particularly limited as long as it is inert to the above reaction and can dissolve or disperse the reaction substrate and the organic amine base. Specifically, aromatic hydrocarbons such as toluene and xylene; ethers such as diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether and 1,4-dioxane; amides such as N, N-dimethylformamide; dimethyl sulfoxide and the like Examples thereof include sulfoxides, and these can be used alone or as a mixed solvent.
The amount of the solvent used is not particularly limited, and the amount by which the reaction smoothly proceeds may be appropriately set according to the reaction conditions such as the amount of the reaction substrate used, the reaction temperature, and the reaction time.
Examples of the organic amine base include N, N-diisopropylethylamine, N, N-dimethylaminopyridine, 1,4-diazabicycloundecene and the like.

The ratio of the secondary amine compounds (V) and (VI) to the dihalogen compound (VII) is not particularly limited.
For example, when a symmetric compound is obtained (when either one of the secondary amine compounds (V) and (VI) is used), 1 equivalent of the dihalogen compound (VII) is taken into consideration in view of the efficiency of the reaction. The secondary amine compound is preferably used in an amount of about 2.0 to 2.3 equivalents.
In addition, when obtaining an asymmetric compound (when using secondary amine compounds (V) and (VI) together), taking into account the efficiency of the reaction, etc., relative to 1 equivalent of dihalogen compound (VII) Each secondary amine compound is preferably used in an amount of about 1.0 to 1.2 equivalents (the total of the secondary amine compounds (V) and (VI) is about 2.0 to 2.4 equivalents).

The use ratio of the dihalogen compound (VII) and the organic amine base is not particularly limited, but considering the efficiency of the reaction, the organic amine base is used in an amount of 2. with respect to 1 equivalent of the dihalogen compound (VII). It is preferable to use about 05 to 5.0 equivalents.
Moreover, although heating temperature and reaction time are not specifically limited, Considering reaction efficiency etc., it is preferable to make it react at 60-120 degreeC for 2 to 8 hours, although it is based also on the solvent to be used.

By containing the diamine compound of the present invention in the outermost surface layer of the photoreceptor, that is, the charge transport layer, it is possible to impart oxidation resistance gas resistance such as ozone resistance and nitrogen oxide resistance to the photoreceptor. This is because the diamine compound of the present invention supplements oxidizing gases such as ozone, nitrogen oxides, chlorine oxides and sulfur oxides, and is effective in adsorbing oxidizing gases to charge generating materials contained in the charge generating layer. This is presumably because it can be suppressed.
Therefore, the photoreceptor containing the diamine compound of the present invention in the charge transport layer of the photosensitive layer has excellent electrophotographic characteristics, is not easily affected by ozone and nitrogen oxides generated from the system, and is stable even after repeated use. It has excellent characteristics and image quality, and can achieve extremely high durability.

In the present invention, the filler particles contained in the outermost surface layer of the photoreceptor, that is, the charge transport layer, are roughly classified into organic filler particles and inorganic filler particles mainly composed of metal oxides.
In general, for the purpose of controlling the wettability of the surface of the photoreceptor and suppressing the adhesion of foreign substances, organic filler particles mainly including a fluorine-based material are used. On the other hand, inorganic filler particles are mainly used for applications aimed at improving printing durability.

In the present invention, a photoreceptor is formed using the latter, that is, inorganic filler particles.
The inorganic filler particles are characterized by high hardness as a material and easy dispersion in the binder resin, such as silicon oxide (silica), titanium oxide, zinc oxide, calcium oxide, aluminum oxide (alumina), etc. And nitride compounds such as silicon nitride and aluminum nitride.

When adding the filler particles to the photoreceptor, the following formula (1) which takes into consideration the particle diameter and dispersion state of the filler particles, not the simple amount of filler particles added:
1.0 × 10 ⁻³ ≦ (df × b ³ ) / (dm × a ³ ) ≦ 2.5 × 10 ⁻² (1)
(Wherein, a means the average distance between filler particles (nm), b means the average filler particle diameter (nm), df means the density of filler particles (g / cm ³ ), Meaning the average density (g / cm ³ ) of the solid content in the outermost surface layer)
In the outermost surface layer of the photoreceptor in a dispersed state satisfying the above. Under such conditions, the photoreceptor exhibits good printing durability.

In the above equation (1), it is assumed that the spherical particles are uniformly distributed in a homogeneous solid medium, and the particles are packed in the medium most closely.
The solid medium on the outermost surface layer of the photoconductor means the binder resin and the charge transport material constituting the charge transport layer, and the filler particles are uniformly distributed.

The average distance between filler particles a is preferably measured by TEM cross-sectional observation, but if a uniform dispersion state can be confirmed, the calculated value is calculated from the amount of filler particles added and the volume of the coating film as the medium. You may ask for it. Specifically, it can be determined from the amount of filler particles added, the particle diameter, the density, and the density of the medium (more precisely, the density of the entire solid content including the filler particles).
The average filler particle diameter b is preferably measured by cross-sectional observation with SEM, but it may be quoted from a catalog value for commercially available filler particles.

The density df of the filler particles can be calculated from these by measuring the volume and weight of the filler particles before production (based on JIS 7112). Good.
The average density dm of the solid content in the outermost surface layer can be calculated from the volume and weight of the coating film. Here, the solid content of the outermost surface layer is a coating film of the charge transport layer obtained by applying a coating liquid and drying the solvent to solidify.

The uniform dispersion state means that the state close to the primary particle diameter in FIG. 3 in the coating solution is fixed even after solidifying as a coating film, and the average particle diameter of the particles in the coating film is the same as before preparation. This refers to a state approximately equal to the primary particle diameter of the raw material particles. That is, in the formula (1), it is assumed that the filler particles are true spheres and have no particle size distribution in a homogeneous solid medium, and these particles are uniformly dispersed in the medium. If the addition amount / particle diameter / density of the filler particles and the density of the medium (more precisely, the density of the entire solid content including the filler particles) are determined, the average distance a between the filler particles is determined. By substituting the obtained value a into the formula (1), it can be determined whether or not the filler particles satisfy the formula (1).
In other words, Equation (1) assumes that the filler particles are uniformly “distributed”. Therefore, in this invention, the addition density | concentration of a filler particle is prescribed | regulated so that dispersion | distribution of the filler particle in a coating liquid / coating film may be uniform, and the said Formula (1) may be satisfy | filled.

The average filler particle distance a is preferably small in order to minimize the adverse effects on light scattering and electrical carriers (electrons and / or holes) in the system. Specifically, 400 nm or less (primary particle diameter) is preferable, and 20 to 200 nm is particularly preferable.
The average filler particle diameter b is preferably 5 to 100 nm, particularly preferably 5 to 20 nm.
Density df is preferably 1.5~7g / cm ² of filler particles, 1.5~3g / cm ² is particularly preferred.
Mean density dm of solids in the outermost surface layer is preferably ^{1~2g / cm 2, 1~1.5g / cm} 2 is particularly preferred.

  In adding the filler particles, a known dispersion method such as a ball mill, a sand mill, an attritor, a vibration mill, an ultrasonic disperser, and a paint shaker can be used to form a uniform particle dispersion state. In order to draw out the excellent characteristics of the electrophotographic photosensitive member, it is desired to grasp the dispersion state in the dispersion for forming the coating film on the surface of the electrophotographic photosensitive member or after the formation of the coating film.

  FIG. 3 is a diagram showing a particle size distribution state in the coating liquid after the dispersion treatment of two types of coating liquids with the same prescription. Specifically, 3.1 g of polycarbonate resin (TS2050: manufactured by Teijin Chemicals) and 3.1 g of silica (TS-610: manufactured by Cabot Specialty Chemicals: primary particle size: 17 nm) were mixed with 55.9 g of tetrahydrofuran to obtain. Each of the obtained mixtures was subjected to a dispersion treatment with a ball mill and a paint shaker for 5 hours, and the particle size distribution of silica particles in the resulting coating solution was measured. In FIG. 3, the ball mill process is indicated by “♦” and the paint shaker process is indicated by “□”.

It can be seen that “♦” is stably dispersed to a state close to the primary particle diameter, while “□” indicates that micron-order aggregates are formed. Although “□” indicates that an aggregate is formed by reaggregation, the detailed cause for obtaining this state has not been elucidated.
The change in the aggregation state as shown in FIG. 3 directly corresponds to the electrical properties and surface uniformity of the final coating film, and the formation of a uniform dispersion close to the primary particle size in the dispersion liquid Reflected. Therefore, the dispersion method of “♦” is preferable because an outermost surface layer having excellent durability can be formed as a result.

In the above, preferred examples of unaggregated filler particles have been given. However, an aggregate of filler particles may be used as long as the formula (1) is satisfied. In the case of an aggregate, “filler particles” in a, b, and df in the formula (1) are read as “aggregates”. Moreover, although the dispersion process by a paint shaker is performed on the conditions in which an aggregate is formed in the above, it can also be made to disperse | distribute to the state close | similar to a primary particle diameter by changing conditions.
In addition, the dispersion state of the filler particles in the coating liquid can be evaluated using, for example, a light scattering particle size distribution measuring apparatus.

As the type of inorganic filler particles, silicon oxide (silica) having a small difference from the refractive index of the medium is suitable as a result of considering light scattering in the system, and light scattering and electrical in the system are preferred. It has been found that a filler having a small particle diameter is preferable in order to minimize the harmful effects on the carrier.
Specifically, silica in which the filler particles have a particle size of 100 nm or less is suitable, preferably 70 to 0.1 nm, more preferably 40 to 1 nm, and more preferably 30 to 5 nm.
Silica having an average particle size in the nm range is preferred.

Next, the configuration of the photoreceptor of the present invention will be specifically described.
1 and 2 are schematic cross-sectional views showing the structure of the main part of the photoreceptor of the present invention.
That is, FIGS. 1 and 2 show a multilayer photosensitive body (hereinafter referred to as “functional separation type photosensitive layer”) in which the photosensitive layer is a multilayer photosensitive layer (hereinafter also referred to as “function separation type photosensitive layer”) composed of a charge generation layer and a charge transport layer. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of the body. The photoreceptor of the present invention may have a reverse two-layered laminated structure in which a charge generating layer and a charge transporting layer are formed in reverse order, but the laminated type is preferred.

In the photoreceptor 1 of FIG. 1, a laminated photosensitive layer 14 in which a charge generation layer 12 and a charge transport layer 13 are laminated in this order is formed on the surface of a conductive support 11.
The photoreceptor 2 in FIG. 2 includes an intermediate layer 15, a laminated photosensitive layer 14 in which a charge generation layer 12 and a charge transport layer 13 are laminated in this order on the surface of a conductive support 11, and a surface protective layer 5. Are formed in this order.

[Conductive support 11 (element tube for photoreceptor)]
The conductive substrate 11 serves as an electrode of the photoreceptor, and other layers, specifically, a laminated photosensitive layer 14 in which a charge generation layer 12 and a charge transport layer 13 are laminated in this order, an intermediate layer. 15 also functions as a support member.
The constituent material of the conductive support is not particularly limited as long as it is a material used in this field.
Specifically, metallic materials such as aluminum, aluminum alloys, copper, zinc, stainless steel, titanium: substrate surface made of polymer materials such as polyethylene terephthalate, polyamide, polyester, polyoxymethylene, polystyrene, hard paper, glass, etc. And metal foil laminated, metal material deposited, conductive polymer, tin oxide, indium oxide or other conductive compound layer deposited or applied.

The shape of the conductive support is not limited to a cylindrical shape as shown in FIGS. 1 and 2, and may be a sheet shape, a columnar shape, an endless belt shape, or the like.
If necessary, the surface of the conductive support 1 is irregularly reflected within a range that does not affect the image quality, such as anodized film treatment, surface treatment with chemicals, hot water, coloring treatment, or roughening the surface. It may be processed.

  The irregular reflection treatment is particularly effective when the photoreceptor according to the present invention is used in an electrophotographic process using a laser as an exposure light source. That is, in the electrophotographic process using a laser as an exposure light source, the wavelength of the laser beam is uniform, so the laser beam reflected on the surface of the photoconductor and the laser beam reflected inside the photoconductor cause interference, Interference fringes due to this interference may appear in the image and cause image defects. Therefore, by performing irregular reflection processing on the surface of the conductive support, it is possible to prevent image defects due to interference of laser light having a uniform wavelength.

[Laminated Photosensitive Layer 14]
The laminated photosensitive layer 14 includes a charge generation layer 12 and a charge transport layer 13. As described above, by assigning the charge generation function and the charge transport function to separate layers, the optimum material constituting each layer can be independently selected.

[Charge generation layer 12]
The charge generation layer 12 contains a charge generation material and, if necessary, a binder resin.
The charge generation material has an ability to generate charges by absorbing light.
As the charge generation material, a compound used in this field can be used.
Specifically, azo pigments (monoazo pigments, bisazo pigments, trisazo pigments, etc.), indigo pigments (indigo, thioindigo, etc.), perylene pigments (peryleneimide, perylene acid anhydride, etc.), polycyclic quinone pigments Pigments (anthraquinone, pyrenequinone, etc.), phthalocyanine pigments (metal phthalocyanine, metal-free phthalocyanine, etc.), squarylium dyes, pyrylium salts, thiopyrylium salts, triphenylmethane dyes (methyl violet, crystal violet, night blue, Victoria blue, etc.) acridine Dyes (erythrosine, rhodamine B, rhodamine 3R, acridine orange, frappeosin, etc.), thiazine dyes (methylene blue, methylene green, etc.), oxazine dyes (capri blue, meldra) Lu, etc.), bisbenzimidazole dyes, quinacridone dyes, quinoline dyes, lake dyes, azo lake dyes, dioxazine dyes, azurenium dyes, triallylmethane dyes, xanthene dyes, cyanine dyes, etc. Examples thereof include organic pigments or dyes (organic photoconductive materials), and inorganic materials such as selenium and amorphous silicon (inorganic photoconductive materials). These charge generating materials can be used alone or in combination of two or more.

Among these charge generating materials, the following structural formula (2):
(Wherein X ¹ , X ² , X ³ and X ⁴ are the same or different and are a halogen atom, an alkyl group or an alkoxy group, and r, s, y and z are the same or different and represent 0-4. Is an integer)
An oxotitanium phthalocyanine compound represented by the formula is particularly preferred.

Examples of the halogen atom of X ¹ , X ² , X ³ and X ^{4 in} the structural formula (2) include fluorine, chlorine, bromine and iodine atoms.
The alkyl group of X ^1, X ^2, X ³ and X ^4, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, alkyl group having 1 to 4 carbon atoms, such as t- butyl group.
Examples of the alkoxy group of X ¹ , X ² , X ³ and X ⁴ include an alkoxy group having 1 to 4 carbon atoms such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy and t-butoxy groups.

  Since the oxotitanium phthalocyanine compound represented by the structural formula (2) has high charge generation efficiency and charge injection efficiency, it generates a large amount of charge by absorbing light and accumulates the generated charge in the molecule. Therefore, the charge is efficiently injected into the charge transport material of the charge transport layer and smoothly transported, so that a highly sensitive and high resolution photoreceptor can be obtained.

  The oxotitanium phthalocyanine compound represented by the structural formula (2) is a known production method such as the method described in Phthhalocyanine Compounds, Reinhold Publishing Corp., New York, 1963 by Moser, Frank H and Arthur L. Thomas. Can be manufactured by.

  For example, among the oxotitanium phthalocyanine compounds represented by the structural formula (2), in the case of unsubstituted oxotitanium phthalocyanine where r, s, y, and z are 0, phthalonitrile and titanium tetrachloride are heated and melted. Or by synthesizing dichlorotitanium phthalocyanine by heating in a suitable solvent such as α-chloronaphthalene and then hydrolyzing with base or water.

  Alternatively, oxotitanium phthalocyanine can also be produced by reacting isoindoline with titanium tetraalkoxide such as tetrabutoxytitanium in a suitable solvent such as N-methylpyrrolidone.

The charge generation layer may contain an appropriate amount of one or more of a chemical sensitizer and an optical sensitizer within a range that does not impair the preferable characteristics of the present invention. These sensitizers improve the sensitivity of the photoreceptor, suppress an increase in residual potential and fatigue due to repeated use, and improve electrical durability. These sensitizers may be contained in the charge transport layer described later, or may be contained in both the charge generation layer and the charge transport layer.
The use ratio of the chemical sensitizer and / or the optical sensitizer is not particularly limited, but a ratio of 10 parts by weight or less is preferable with respect to 100 parts by weight of the charge generation material, and a ratio of 0.5 to 2.0 parts by weight Is particularly preferred.

  Examples of chemical sensitizers include acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride, and 4-chloronaphthalic anhydride; cyano compounds such as tetracyanoethylene and terephthalmalondinitrile, and 4-nitrobenzaldehyde. Aldehydes; anthraquinones such as anthraquinone and 1-nitroanthraquinone; polycyclic or heterocyclic nitro compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitrofluorenone; diphenoquinone compounds Examples thereof include electron-withdrawing materials and those obtained by polymerizing these electron-withdrawing materials.

  Examples of the optical sensitizer include xanthene dyes, quinoline pigments, organic photoconductive compounds such as copper phthalocyanine, triphenylmethane dyes typified by methyl violet, crystal violet, knight blue and victoria blue; erythrosin, Acridine dyes typified by rhodamine B, rhodamine 3R, acridine orange and frappeocin; thiazine dyes typified by methylene blue and methylene green; oxazine dyes typified by capri blue and meldra blue; cyanine dyes; styryl dyes; Examples include pyrylium salt dyes and thiopyrylium salt dyes.

  As the binder resin, for example, it is used for the purpose of improving the mechanical strength, durability and the like of the charge generation layer, and a resin having a binding property used in this field can be used, and is compatible with the diamine compound of the present invention. What is excellent in is preferable.

  Specifically, vinyl resins such as polymethyl methacrylate, polystyrene, polyvinyl chloride, polycarbonate, polyester, polyester carbonate, polysulfone, polyarylate, polyamide, methacrylic resin, acrylic resin, polyether, polyacrylamide, polyphenylene oxide, etc. Thermoplastic resin: Thermosetting resin such as phenoxy resin, epoxy resin, silicone resin, polyurethane, phenol resin, alkyd resin, melamine resin, phenoxy resin, polyvinyl butyral, polyvinyl formal, partially cross-linked products of these resins, these resins Copolymer resins containing two or more of the structural units contained in (vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, acrylo Tolyl - insulating resin such as styrene copolymer resin). These binder resins can be used alone or in combination of two or more.

The use ratio of the charge generation material and the binder resin is not particularly limited, but when the weight G of the charge generation material and the weight B of the binder resin are used, the ratio G / B is 10/100 or more and 200/100 or less. Of 50/150 or more and 150/100 or less is particularly preferable.
When the ratio G / B is less than 10/100, the sensitivity of the photoreceptor may be lowered.
On the other hand, when the ratio G / B exceeds 200/100, there is a possibility that the film strength of the charge generation layer is lowered, the dispersibility of the charge generation material is lowered, and coarse particles are increased. The surface charge of the image is reduced by exposure, and there is a possibility that image fogging, in particular, fogging of an image called a black spot where a toner adheres to a white background and a minute black spot is formed.

The charge generation layer 3 can be formed by a known dry method and wet method.
Examples of the dry method include a method in which a charge generation material is subjected to J vacuum deposition on the conductive support 11.
As a wet method, for example, a charge generation material and, if necessary, a binder resin are dissolved or dispersed in an appropriate organic solvent to prepare a coating solution for forming a charge generation layer, and this coating solution is applied to the surface of the conductive support 11. Alternatively, a method of applying to the surface of the intermediate layer 15 formed on the conductive support 11 and then drying to remove the organic solvent can be mentioned.

  Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, and dichlorobenzene; halogenated hydrocarbons such as dichloromethane, dichloroethane, and tetrachloropropane; tetrahydrofuran (THF) , Ethers such as dioxane, dibenzyl ether, dimethoxymethyl ether, 1,2-dimethoxyethane; ketones such as methyl ethyl ketone, cyclohexanone, acetophenone, isophorone; esters such as methyl benzoate, ethyl acetate, butyl acetate, diphenyl sulfide Sulfur-containing solvents such as: Fluorinated solvents such as hexafluoroisopropanol; non-protons such as N, N-dimethylformamide and N, N-dimethylacetamide Such as a polar solvent and the like, which may be used alone or as a mixed solvent. A mixed solvent obtained by adding alcohols, acetonitrile, or methyl ethyl ketone to such a solvent can also be used. Among these solvents, non-halogen organic solvents are particularly preferable in consideration of the global environment.

Prior to dissolving or dispersing the constituent materials in the resin solution, the charge generating material may be pre-ground.
The preliminary pulverization can be performed using a general pulverizer such as a ball mill, a sand mill, an attritor, a vibration mill, or an ultrasonic disperser.
The dissolution or dispersion of the constituent materials in the resin solution can be performed using, for example, a general disperser such as a paint shaker, a ball mill, or a sand mill. At this time, it is preferable to appropriately set the dispersion condition so that impurities are generated from the container and the members constituting the disperser due to wear and the like and are not mixed into the coating liquid.

Examples of the method for applying the charge generation layer forming coating solution include roll coating, spray coating, blade coating, ring coating, and dip coating.
The dip coating method is a method of forming a layer on the conductive support 1 by immersing the conductive support 1 in a coating tank filled with a coating solution and then pulling it up at a constant speed or a speed that changes sequentially. . Since this method is relatively simple and excellent in terms of productivity and cost, it is widely used for producing an electrophotographic photosensitive member. In addition, you may provide the coating liquid dispersion | distribution apparatus represented by the ultrasonic generator in the apparatus used for the dip coating method in order to stabilize the dispersibility of a coating liquid.

  The charge generation layer may be one kind selected from a hole transport material, an electron transport material, an antioxidant, a dispersion stabilizer, a sensitizer, a leveling agent, a plasticizer, fine particles of an inorganic compound or an organic compound, if necessary. Two or more kinds may be included in appropriate amounts.

Examples of the antioxidant include phenol compounds, hydroquinone compounds, tocopherol compounds, and amine compounds. Among these, hindered phenol derivatives are particularly preferable.
The amount of the antioxidant used is preferably from 0.1 to 50 parts by weight, particularly preferably from 1 to 20 parts by weight, per 100 parts by weight of the charge transport material. If the amount of the antioxidant used is less than 0.1 parts by weight, it may not be possible to obtain a sufficient effect for improving the stability of the coating solution and improving the durability of the photoreceptor. On the other hand, if the amount of the antioxidant used exceeds 50 parts by weight, the photoreceptor characteristics may be adversely affected.

Plasticizers or leveling agents can improve film formability, flexibility, and surface smoothness.
Examples of the plasticizer include biphenyl, biphenyl chloride, benzophenone, o-terphenyl, dibasic acid ester (for example, phthalic acid ester), fatty acid ester, phosphate ester, various fluorohydrocarbons, chlorinated paraffin, and epoxy type plasticizer. Etc.
Examples of the leveling agent (surface modifier) include a silicone leveling agent such as silicone oil and a fluororesin leveling agent.
Fine particles of an inorganic compound or an organic compound can enhance mechanical strength and improve electrical characteristics.

  The thickness of the charge generation layer 12 is not particularly limited, but is preferably 0.05 to 5 μm, particularly preferably 0.1 to 1 μm. This is because if the film thickness of the charge generation layer is less than 0.05 μm, the efficiency of light absorption may be reduced and the sensitivity may decrease. Conversely, if the film thickness of the charge generation layer exceeds 5 μm, In this case, the charge transport in this process becomes a rate-determining step in the process of erasing the charge on the surface of the photoreceptor, and the sensitivity may be lowered.

[Charge transport layer 13]
The charge transport layer 13 contains a charge transport material, the diamine compound of the present invention, filler particles, and, if necessary, a binder resin.
The charge transport material has an ability to accept and transport charges generated by the charge generation material, and includes a hole transport material and an electron transport material.
As the hole transport material, a compound used in this field can be used.
Specifically, carbazole derivatives, pyrene derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, many Ring aromatic compounds, indole derivatives, pyrazoline derivatives, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, triarylmethane derivatives, phenylenediamine derivatives, stilbene derivatives , Enamine derivatives, benzidine derivatives, polymers having groups derived from these compounds in the main chain or side chain (Polymers) -N- vinylcarbazole, poly-1-vinylpyrene, ethylcarbazole - formaldehyde resins, triphenylmethane polymers, poly-9-vinyl anthracene, etc.), etc. polysilane and the like. These hole transport materials can be used alone or in combination of two or more.

Moreover, as an electron transport substance, the compound used in the said field | area can be used.
Specifically, organic compounds such as benzoquinone derivatives, tetracyanoethylene derivatives, tetracyanoquinodimethane derivatives, fluorenone derivatives, xanthone derivatives, phenanthraquinone derivatives, phthalic anhydride derivatives, diphenoquinone derivatives, amorphous silicon, amorphous selenium, Examples include inorganic materials such as tellurium, selenium-tellurium alloy, cadmium sulfide, antimony sulfide, zinc oxide, and zinc sulfide. These charge transport materials can be used alone or in combination of two or more.

The charge transport layer in the photoreceptor of the present invention has the general formula (IV)

Wherein R ₁ and R ₂ are the same or different and are a lower alkyl group, or R ₁ and R ₂ may be bonded to each other to form a heterocyclic group containing a nitrogen atom; Is an integer of 1 to 4, Ar is an aromatic ring group having a butadiene group)
It is preferable to further contain an amine compound represented by:
The amine compound represented by the general formula (IV) is preferable because it has resistance to gases such as ozone and NOx generated in the electrophotographic process.

Examples of the diamine compound of the present invention include the aforementioned compounds.
The use ratio of the charge transport material T and the diamine compound J of the present invention is not particularly limited, but when the weight transport material T and the diamine compound weight J are used, the ratio T / J is 100 / 0.01. It is preferably 100 / 20.0 or less, particularly preferably 100 / 0.1 or more and 100 / 10.0 or less.
If the use ratio of the charge transport material T and the diamine compound J of the present invention is within the above range, ozone resistance is not affected without adversely affecting the characteristics of the photoreceptor, such as deterioration in sensitivity and increase in residual potential during repeated use. An electrophotographic photosensitive member having improved nitrogen oxide resistance can be provided.
When the ratio T / J is less than 100 / 0.01, sufficient resistance to oxidizing gases such as ozone and nitrogen oxides cannot be obtained, resulting in a decrease in image quality, a decrease in charging potential and a decrease in sensitivity during repeated use. May happen.
On the other hand, when the ratio T / J exceeds 100 / 20.0, the sensitivity and responsiveness are lowered, and there is a possibility that the residual potential is increased during repeated use.

  Examples of the filler particles include the aforementioned compounds. The filler particles are dispersed in the outermost surface layer of the photoreceptor, that is, the electron transport layer so as to satisfy the formula (1).

As the binder resin, one or more of the same binder resins as those contained in the charge generation layer can be used.
Among such resins, polystyrene, polycarbonate, polyarylate and polyphenylene oxide are particularly excellent in compatibility with the diamine compound of the present invention, and have a volume resistivity of 10 ¹³ Ω or more and excellent electrical insulation, and Polycarbonate is particularly preferred because it is excellent in film formability, potential characteristics and the like.

  The use ratio of the charge transport material and the binder resin is not particularly limited, but the ratio T / B is 10/12 or more and 10/30 or less when the weight T of the charge transport material and the weight B of the binder resin are used. Is preferred.

When the charge transport layer is formed by a dip coating method, if the ratio T / B exceeds 10/30, the viscosity of the coating solution increases, the coating speed decreases, and the productivity may be significantly deteriorated. Furthermore, 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 may occur, and the formed charge transport layer may become cloudy.
On the other hand, if the ratio T / B is less than 10/12, the printing durability of the photosensitive layer is lowered, the amount of film loss due to repeated use is increased, and the chargeability of the photoreceptor may be lowered.

  The charge transport layer may contain the same additive as that contained in the charge generation layer, if necessary, in addition to the two essential components.

The charge transport layer 13 is prepared by dissolving or dispersing a charge transport material, the diamine compound of the present invention, filler particles, a binder resin and other additives as required in an appropriate organic solvent to prepare a coating solution for forming a charge transport layer. The coating solution can be formed on the surface of the charge generation layer 12 and then dried to remove the organic solvent. More specifically, for example, a charge transport layer forming coating solution is prepared by dissolving or dispersing a charge transport substance and, if necessary, other additives in a resin solution obtained by dissolving a binder resin in an organic solvent. Prepare.
The other steps and the conditions thereof are in accordance with the formation of the charge generation layer, but it is necessary to disperse the filler particles so as to satisfy the formula (1).

  The thickness of the charge transport layer 13 is not particularly limited, but is preferably 5 to 40 μm, and particularly preferably 10 to 30 μm. If the thickness of the charge transport layer is less than 5 μm, the charge holding ability on the surface of the photoconductor may be reduced. Conversely, if the thickness of the charge transport layer exceeds 40 μm, the resolution of the photoconductor may be reduced.

[Intermediate layer 15 (also referred to as “undercoat layer”)]
The photoreceptor of the present invention preferably has an intermediate layer between the conductive support and the laminated photosensitive layer.
The intermediate layer has a function of preventing charge injection from the conductive support to the laminated photosensitive layer. That is, a decrease in chargeability of the laminated photosensitive layer is suppressed, a decrease in surface charge other than a portion to be erased by exposure is suppressed, and occurrence of image defects such as fog is prevented. In particular, during image formation by the reversal development process, it is possible to prevent the occurrence of image fogging called black spots in which minute black dots made of toner are formed on a white background portion.
In addition, the intermediate layer covering the surface of the conductive support with the intermediate layer reduces the degree of unevenness, which is a defect on the surface of the conductive support, and makes the surface uniform, thereby improving the film formability of the multilayer photosensitive layer. The adhesion between the conductive support and the laminated photosensitive layer can be improved.

  The intermediate layer is formed, for example, by dissolving a resin material in an appropriate solvent to prepare a coating solution for forming an intermediate layer, applying this coating solution to the surface of the conductive support, and removing the organic solvent by drying. it can.

Examples of the resin material include natural polymer materials such as casein, gelatin, polyvinyl alcohol, and ethyl cellulose in addition to the same binder resin as that contained in the charge generation layer, and one or more of these materials are used. it can. Among these resins, polyamide resins are preferable, and alcohol-soluble nylon resins are particularly preferable.
Examples of alcohol-soluble nylon resins include copolymerized nylons obtained by copolymerizing 6-nylon, 6,6-nylon, 6,10-nylon, 11-nylon, 12-nylon, and the like; N-alkoxymethyl-modified nylon and N- Examples thereof include a resin obtained by chemically modifying nylon such as alkoxyethyl-modified nylon.

Examples of the solvent for dissolving or dispersing the resin material include water, alcohols such as methanol, ethanol and butanol, glymes such as methyl carbitol and butyl carbitol, and mixed solvents in which two or more of these solvents are mixed. Can be mentioned.
Other processes and conditions are in accordance with the formation of the charge generation layer.

Moreover, the coating liquid for intermediate | middle layer formation may contain the metal oxide particle.
The metal oxide particles can easily adjust the volume resistance value of the intermediate layer, can further suppress the injection of charges into the laminated photosensitive layer, and can maintain the electrical characteristics of the photoreceptor in various environments.
Examples of the metal oxide particles include titanium oxide, aluminum oxide, aluminum hydroxide, and tin oxide. The particle diameter is preferably in the range of 0.02 to 0.5 μm.
When the total content of the resin material and the metal oxide particles in the coating liquid for forming the intermediate layer is C and the content of the solvent is D, the weight ratio (C / D) of both is 1/99 to 40/60. Is preferable, and 2/98 to 30/70 is particularly preferable.
The weight ratio (E / F) of the resin material content (E) and the metal oxide particle content (F) is preferably 1/99 to 90/10, and preferably 5/95 to 70/30. Particularly preferred.

Although the film thickness of an intermediate | middle layer is not specifically limited, 0.01-20 micrometers is preferable, and 0.05-10 micrometers is especially preferable. If the thickness of the intermediate layer is less than 0.01 μm, it may not function substantially as the intermediate layer, and there is a possibility that a uniform surface cannot be obtained by covering the defects of the conductive support, and the thickness of the intermediate layer is 20 μm. If it exceeds 1, it is difficult to form a uniform intermediate layer, and the sensitivity of the photoreceptor may be lowered.
In addition, when the constituent material of an electroconductive support body is aluminum, the layer (alumite layer) containing an alumite can be formed and it can be set as an intermediate | middle layer.

The method for producing a photoreceptor of the present invention includes a drying step for each layer such as the charge generation layer 12, the charge transport layer 13, and the intermediate layer 15.
The drying temperature of the photoreceptor is suitably about 50 ° C. to about 140 ° C., and particularly preferably about 80 ° C. to about 130 ° C. When the drying temperature of the photoreceptor is less than about 50 ° C., the drying time may be long. When the drying temperature exceeds about 140 ° C., the electrical characteristics during repeated use deteriorate and the photoreceptor can be used. The image may also deteriorate.

  An image forming apparatus according to the present invention includes a photosensitive member according to the present invention, a charging unit that charges the photosensitive member, an exposure unit that exposes the charged photosensitive member, and an electrostatic latent image formed by exposure. And a transfer means for transferring the electrostatic latent image onto a transfer material.

The image forming apparatus (laser printer) of the present invention will be described with reference to the drawings, but is not limited to the following description.
FIG. 4 is a schematic side view showing the configuration of the image forming apparatus of the present invention.

A laser printer 30 as an image forming apparatus includes a photosensitive member 1, a semiconductor laser (or light emitting diode) 31, a rotary polygon mirror 32, an imaging lens 34, a mirror 35, a corona charger 36 as a charging unit, and a development as a developing unit. 37, transfer paper cassette 38, paper feed roller 39, registration roller 40, transfer charger 41 as transfer means, separation charger 42, transport belt 43, fixing device 44, paper discharge tray 45, and cleaner 46 as cleaning means. It is comprised including.
The semiconductor laser 31, the rotary polygon mirror 32, the imaging lens 34, and the mirror 35 constitute an exposure unit 49.

  The photoreceptor 1 is mounted on the laser printer 30 so as to be rotatable in the direction of an arrow 47 by a driving unit (not shown). A laser beam 33 emitted from the semiconductor laser 31 is repeatedly scanned in the longitudinal direction (main scanning direction) with respect to the surface of the photoreceptor 1 by the rotary polygon mirror 32. The imaging lens 34 has f-θ characteristics, and the laser beam 33 is reflected by the mirror 35 to form an image on the surface of the photosensitive member 1 for exposure. By scanning the laser beam 33 as described above to form an image while rotating the photoconductor 1, an electrostatic latent image corresponding to image information is formed on the surface of the photoconductor 1.

  The corona charger 36, the developing device 37, the transfer charger 41, the separation charger 42 and the cleaner 46 are provided in this order from the upstream side to the downstream side in the rotation direction of the photosensitive member 1 indicated by an arrow 47.

  The corona charger 36 is provided on the upstream side of the image forming point of the laser beam 33 in the rotation direction of the photoconductor 1 and uniformly charges the surface of the photoconductor 1. Therefore, the laser beam 33 exposes the surface of the photosensitive member 1 that is uniformly charged, and a difference occurs between the charged amount of the portion exposed by the laser beam 33 and the charged amount of the portion not exposed. Electrostatic latent image is formed.

  The developing device 37 is provided on the downstream side in the rotation direction of the photosensitive member 1 with respect to the image forming point of the laser beam 33, supplies toner to the electrostatic latent image formed on the surface of the photosensitive member 1, and converts the electrostatic latent image into toner. Develop as an image. The transfer paper 48 accommodated in the transfer paper cassette 38 is taken out one by one by the paper feed roller 39 and is given to the transfer charger 41 by the registration roller 40 in synchronism with the exposure of the photoreceptor 1. The toner image is transferred onto the transfer paper 48 by the transfer charger 41. A separation charger 42 provided in the vicinity of the transfer charger 41 discharges the transfer paper onto which the toner image has been transferred and separates it from the photoreceptor 1.

The transfer paper 48 separated from the photoreceptor 1 is conveyed to the fixing device 44 by the conveying belt 43, and the toner image is fixed by the fixing device 44. The transfer paper 48 on which the image is formed in this manner is discharged toward the paper discharge tray 45. In addition, after the transfer paper 48 is separated by the separation charger 42, the photoreceptor 1 that continues to rotate further cleans foreign matters such as toner and paper dust remaining on the surface by the cleaner 46. The photoreceptor 1 whose surface has been cleaned by the cleaner 46 is neutralized by a neutralizing lamp (not shown) provided together with the cleaner 46 and then further rotated, and a series of image forming operations starting from the charging of the photoreceptor 1 are repeated. .
In addition, it is possible to employ a configuration in which a plurality of photosensitive members are provided to form a superimposed image using a plurality of different toners. This configuration is called a tandem system.

The present invention will be specifically described below with reference to production examples, examples and comparative examples, but the present invention is not limited to these production examples and examples.
In addition, the chemical structure, molecular weight, and elemental analysis of the compound obtained by the synthesis example were measured with the following apparatuses and conditions.

(Chemical structure)
Nuclear magnetic resonance apparatus: NMR (Bruker Biospin, model: DPX-200)
Sample preparation Approximately 4 mg sample / 0.4 m (CDCl 3)
Measurement mode ¹ H (normal), ¹³ C (normal, DPET-135)

(Molecular weight)
Molecular weight measuring device: LC-MS (manufactured by Thermoquest,
(Finegan LCQ Deca Mass Spectrometer System)
LC column GL-Sciences Inertsil ODS-3 2.1 × 100mm
Column temperature 40 ° C
Eluent methanol: water = 90: 10
Sample injection volume 5 μl
Detector UV254nm and MS ESI

(Elemental analysis)
Elemental analysis device: Perkin Aelmer, Elemental Analysis 2400
Sample amount: Weigh accurately about 2 mg Gas flow rate (ml / min): He = 1.5, O ₂ = 1.1, N ₂ = 4.3
Combustion tube temperature setting: 925 ° C
Reduction tube temperature setting: 640 ° C
In addition, the elemental analysis was analyzed by the simultaneous determination method of carbon (C), hydrogen (H) and nitrogen (N) by the differential thermal conductivity method.

(Synthesis Example 1)
In the above reaction formula, 4,4′-bis (chloromethyl) biphenyl is used as the amine compound represented by general formula (V) and general formula (VI), and dibenzylamine is used as the dihalogen compound represented by general formula (VII). According to the following reaction formula used, Exemplified Compound No. 1 (Structural Formula (I)) was synthesized.

[Production of Amine-Bisaldehyde Intermediate]
In 50 ml of anhydrous 1,4-dioxane, 6.06 g (1.0 equivalent) of 4,4′-bis (chloromethyl) biphenyl and 10.0 g (2.1 equivalent) of dibenzylamine were added, and iced on an ice bath. Cooled under cold. To this solution, 6.86 g (2.2 equivalents) of N, N-diisopropylethylamine was gradually added. Then, it heated gradually, raised reaction temperature to 100-110 degreeC, and stirred for 4 hours, heating so that 100-110 degreeC might be maintained. After completion of the reaction, the reaction solution is allowed to cool, and the resulting precipitate is collected by filtration, washed thoroughly with water, and re-reused with a mixed solvent of ethanol and ethyl acetate (ethanol: ethyl acetate = 8: 2 to 7: 3). By performing crystallization, 12.1 g of a white powdery compound was obtained.

As a result of chemical analysis of the obtained white powdery compound,
Nuclear magnetic resonance equipment: NMR
¹ H-NMR spectrum (normal) showed δ (ppm) = 3.58 (S.12H) 7.07 7.84 (m.28H).
The ¹³ C-NMR spectrum (usually DPET-135) has δ = 57.80 (CH ₂ , signal intensity 2), 58.07 (CH 2, signal intensity 4), 126.94 (CH, signal intensity 4). ), 128.32 (CH, signal intensity 8), 128.72 (CH, signal intensity 4), 128.83 (CH, signal intensity 4), 128.85 (CH, signal intensity 8), 138.29 ( C, signal intensity 2), 139.25 (C, signal intensity 4), and 139.28 (C, signal intensity 2) were shown.
Furthermore, the molecular weight measuring device: LC-MS is exemplified by Compound No. A peak corresponding to a molecular ion [M + H] ⁺ in which a proton is added to 1 (calculated molecular weight: 572.30) was observed at 573.2.

The elemental analysis values of the white powdery compound were as follows.
<Exemplary Compound No. Elemental analysis value of 1>
Theoretical value C: 88.07%, H: 7.04%, N: 4.89%
Actual value C: 87.25%, H: 6.88%, N: 4.42%
As described above, from the results of analysis such as NMR, LC-MS, and elemental analysis, the obtained white powdery compound was found to be Compound No. 1 diamine compound (yield: 87.5%). Moreover, from the analysis result of HPLC at the time of LC-MS measurement, the obtained exemplary compound No. The purity of 1 was 99.0%.

(Production Examples 2 to 11)
Exemplified compounds were prepared in the same manner as in Production Example 1 using the amine compounds represented by the general formulas (V) and (VI) and the raw material compounds shown in Table 2 as the dihalogen compounds represented by the general formula (VII). No. 2, 4, 8, 14, 22, 29, 38, 50, 53 and 57 were synthesized, respectively. In Table 2, Exemplified Compound No. 1 raw material compounds are also shown.

  In addition, Tables 3-1 to 3-3 show the elemental analysis values, the calculated molecular weight values, and the actual measurement values [M + H] obtained by LC-MS of the respective exemplary compounds obtained in Production Examples 1 to 11 above.

(Example 1)
Exemplified Compound No. 1 which is the diamine compound according to the present invention produced in Production Example 1 as follows. A photoreceptor having 1 in the charge generation layer was prepared.
As the conductive support, an aluminum cylindrical conductive support having an outer diameter of 30 mm and a length in the longitudinal direction of 340 mm was used.

  3 g of titanium oxide (trade name: Taibake TTO55A, manufactured by Ishihara Sangyo Co., Ltd.), 3 g of alcohol-soluble copolymer nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.), 60 g of methyl alcohol and 40 g of 1,3-dioxolane, Dispersion treatment was carried out for 10 hours with a paint shaker to prepare 100 g of an intermediate layer forming coating solution. This intermediate layer forming coating solution was applied onto an aluminum cylindrical conductive support as a conductive support by a dip coating method and naturally dried to form an intermediate layer having a thickness of 0.9 μm.

  Subsequently, 15 g of titanyl phthalocyanine represented by the following structural formula (3) (for example, produced by the method described in Japanese Patent No. 3569422) as a charge generating substance, polyvinyl butyral resin (trade name: ESREC BM-2, Sekisui Chemical Co., Ltd.) 10 g of company) and 1400 g of 1,3-dioxolane were dispersed in a ball mill for 72 hours to prepare 50 g of a charge generation layer forming coating solution. This charge generation layer forming coating solution was applied to the surface of the previously provided intermediate layer by the same method as that for the intermediate layer and dried naturally to form a charge generation layer having a thickness of 0.2 μm.

Next, silica particles (average particle size: 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) 3.54 g and polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 3.54 g as filler particles. Was mixed with 63.8 g of tetrahydrofuran. The obtained mixture was subjected to dispersion treatment with a ball mill for 5 hours using ZrO ₂ beads (Φ3 mm) as a medium to prepare a primary dispersion coating solution for a charge transport layer.
At this stage, the filler particles are uniformly dispersed, and the dispersion state corresponding to the primary particle size (about 17 nm) is maintained. A light scattering particle size distribution analyzer (Microtrac UPA-150, Nikkiso Co., Ltd.) (Made by company).

  Next, 100 g of a butadiene compound (trade name: T-405, manufactured by Takasago Chemical Co., Ltd.) represented by the following structural formula (4) as a charge transport material, 176 g of a polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) and a diamine Exemplified Compound No. produced in Production Example 1 as a compound. 1 2.50 g was mixed with 1080 g of tetrahydrofuran and dissolved. The primary dispersion coating liquid for charge transport layer was mixed with the obtained solution and stirred for 15 hours in a ball mill to prepare a secondary dispersion coating liquid for charge transport layer. This secondary dispersion coating solution for the charge transport layer is applied to the surface of the charge generation layer previously provided by the same method as that for the intermediate layer and dried at 130 ° C. for 1 hour to obtain a charge transport layer having a thickness of 28 μm. Formed. In this way, a laminated photoreceptor according to the present invention having a laminated structure in which an intermediate layer, a charge generation layer, and a charge transport layer are sequentially laminated on the conductive support shown in FIG. 2 was produced.

(Examples 2 to 5)
Exemplified Compound No. 1 produced in Production Example 1 In place of Exemplified Compound No. 1 A multilayer photoreceptor according to the present invention was produced in the same manner as in Example 1 except that 2, 4, 8, and 14 were used.

(Examples 6 to 8)
Exemplified Compound No. 1 produced in Production Example 1 1 In place of 2.50 g, Exemplified Compound No. 1 A multilayer photoreceptor according to the present invention was produced in the same manner as in Example 1 except that 0.10 g, 20.0 g, and 30.0 g of 1 were used.

Example 9
Silica particles (average particle size: 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) 0.207 g and polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 0.207 g as tetrahydrofuran are used as filler particles. 3.73 g mixed and dispersed to prepare a primary dispersion coating solution for a charge transport layer, and a butadiene compound represented by the above structural formula (4) as a charge transport material (trade name: T-405, Takasago) Fragrance Co., Ltd.) 100 g, polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 180 g, and exemplified compound No. 1 produced in Production Example 1 as a diamine compound. 1 2.50 g was mixed and dissolved in 1127 g of tetrahydrofuran, and the primary dispersion coating liquid for charge transport layer was mixed and stirred to prepare a secondary dispersion coating liquid for charge transport layer. Similarly, a multilayer photoreceptor according to the present invention was produced.

(Example 10)
Silica particles (average particle size: 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) 1.41 g and polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 1.41 g as tetrahydrofuran as filler particles The mixture was mixed in 25.3 g and dispersed to prepare a primary dispersion coating solution for a charge transport layer, and the butadiene compound represented by the above structural formula (4) as a charge transport material (trade name: T-405, Takasago) Perfume Co., Ltd.) 100 g, polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 179 g and the exemplified compound No. 1 produced in Production Example 1 as a diamine compound. 1 2.50 g was mixed and dissolved in 1110 g of tetrahydrofuran, the primary dispersion coating liquid for charge transport layer was mixed, and the mixture was stirred to prepare a secondary dispersion coating liquid for charge transport layer. Similarly, a multilayer photoreceptor according to the present invention was produced.

Example 11
Silica particles (average particle size: 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) 5.31 g and polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 5.31 g are used as the filler particles in tetrahydrofuran. The mixture was mixed with 95.5 g and dispersed to prepare a primary dispersion coating solution for a charge transport layer, and the butadiene compound represented by the above structural formula (4) as a charge transport material (trade name: T-405, Takasago) Fragrance Co., Ltd.) 100 g, polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 174.7 g and the exemplified compound No. 1 produced in Production Example 1 as a diamine compound. 1 2.50 g was mixed and dissolved in 998 g of tetrahydrofuran, and the primary dispersion coating liquid for charge transport layer was mixed and stirred to prepare a secondary dispersion coating liquid for charge transport layer. Similarly, a multilayer photoreceptor according to the present invention was produced.

Example 12
Instead of silica particles (average particle size: 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) as filler particles, alumina particles (average particle diameter: 400 nm, trade name: Sumiko Random AA-04, Sumitomo) A laminated photoreceptor according to the present invention was produced in the same manner as in Example 1 except that Chemical Industries, Ltd. was used.

(Example 13)
Instead of silica particles (average particle size: 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) as filler particles, silica particles (average particle size: 100 nm, trade name: X-24-9163A, Shin-Etsu) A laminated photoreceptor according to the present invention was produced in the same manner as in Example 1 except that Chemical Industries, Ltd. was used.

(Example 14)
Instead of silica particles (average particle size: 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) as filler particles, silica particles (average particle size: 250 nm, trade name: SO-E1, Admatex Co., Ltd.) A laminated photoreceptor according to the present invention was produced in the same manner as in Example 1 except that the product manufactured by the company was used.

(Example 15)
Instead of silica particles (average particle size: 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) as filler particles, silica particles (average particle size: 1500 nm, trade name: SO-E5, Admatex Co., Ltd.) A laminated photoreceptor according to the present invention was produced in the same manner as in Example 1 except that the product manufactured by the company was used.

(Example 16)
Instead of 100 g of the butadiene compound represented by the above structural formula (4) as a charge transport material, 90 g of a triarylamine compound (manufactured by Nippon Distillation Co., Ltd.) represented by the following structural formula (5) and the following structural formula (6) A laminated photoreceptor according to the present invention was produced in the same manner as in Example 1 except that 10 g of the butadiene compound (manufactured by Takasago Inc.) shown in FIG.

(Example 17)
Implemented except that 100 g of a triarylamine compound (manufactured by Nippon Distillation Co., Ltd.) represented by the above structural formula (5) was used in place of 100 g of the butadiene compound represented by the above structural formula (4) as a charge transport material. In the same manner as in Example 1, a multilayer photoreceptor according to the present invention was produced.

(Example 18)
Implemented except that 100 g of a styryl compound (manufactured by Hodogaya Chemical Co., Ltd.) represented by the following structural formula (7) was used in place of 100 g of the butadiene compound represented by the above structural formula (4) as a charge transport material. In the same manner as in Example 1, a multilayer photoreceptor according to the present invention was produced.

(Comparative Example 1)
Silica particles (average particle diameter: 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) 0.140 g and polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 0.140 g as tetrahydrofuran are used as filler particles. 2.52 g was mixed and dispersed to prepare a primary dispersion coating solution for a charge transport layer, and the butadiene compound represented by the above structural formula (4) as a charge transport material (trade name: T-405, Takasago) Fragrance Co., Ltd.) 100 g, polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 180 g, and exemplified compound No. 1 produced in Production Example 1 as a diamine compound. 1 2.50 g was mixed with 1128 g of tetrahydrofuran and dissolved, and the primary dispersion coating liquid for charge transport layer was mixed and stirred to prepare a secondary dispersion coating liquid for charge transport layer. In the same manner, a multilayer photoreceptor was produced.

(Comparative Example 2)
Silica particles (average particle diameter 17 nm, trade name: TS-610, manufactured by Cabot Specialty Chemicals) 5.71 g and polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 5.71 g as filler particles and tetrahydrofuran 103 g And a dispersion treatment to prepare a primary dispersion coating solution for a charge transport layer, and a butadiene compound represented by the above structural formula (4) as a charge transport material (trade name: T-405, manufactured by Takasago International Corporation) ) 100 g, polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 174 g and exemplified compound No. manufactured in Production Example 1 as a diamine compound. 1 2.50 g was mixed and dissolved in 1050 g of tetrahydrofuran, and the primary dispersion coating liquid for charge transport layer was mixed and stirred to prepare a secondary dispersion coating liquid for charge transport layer. In the same manner, a multilayer photoreceptor was produced.

(Comparative Example 3)
Exemplified compound No. 1 produced in Production Example 1 as a diamine compound. 1 A laminated photoreceptor was prepared in the same manner as Comparative Example 1 except that 2.50 g was not used.

(Comparative Example 4)
Exemplified compound No. 1 produced in Production Example 1 as a diamine compound. 1 A laminated photoreceptor was prepared in the same manner as Comparative Example 2 except that 2.50 g was not used.

(Comparative Example 5)
Exemplified Compound No. 1 produced in Production Example 1 1 As in Example 1, except that 2.50 g of an antioxidant (trade name: Irganox 1010, manufactured by Ciba Specialty Chemicals) represented by the following structural formula (8) was used instead of 2.50 g. In this way, a multilayer photoreceptor was produced.

(Comparative Example 6)
Exemplified Compound No. 1 produced in Production Example 1 1 Laminated type in the same manner as in Example 1 except that 5.0 g of an antioxidant represented by the following structural formula (9) (trade name: Sumilizer BHT, manufactured by Sumitomo Chemical Co., Ltd.) was used instead of 2.50 g. A photoconductor was prepared.

(Comparative Example 7)
Exemplified Compound No. 1 produced in Production Example 1 1 Example except that 2.50 g of a known antioxidant (trade name: TINUVIN 622, molecular weight 3100 to 4000, manufactured by Ciba Geigy Japan Ltd.) represented by the following structural formula (10) was used instead of 2.50 g In the same manner as in Example 1, a multilayer photoreceptor was produced.

(Comparative Example 8)
Exemplified Compound No. 1 produced in Production Example 1 1 A laminated photoreceptor was produced in the same manner as in Example 1 except that 2.50 g of a known antioxidant (manufactured by Tokyo Chemical Industry) represented by the following structural formula (11) was used instead of 2.50 g. .

(Comparative Example 9)
Instead of the secondary dispersion coating solution for the charge transport layer, 100 g of a butadiene compound (trade name: T-405, manufactured by Takasago Fragrance Co., Ltd.) represented by the structural formula (4) as a charge transport material, polycarbonate resin (trade name: TS2050, manufactured by Teijin Chemicals Ltd.) 176 g and the exemplified compound No. 1 produced in Production Example 1 as a diamine compound. 1 A laminated photoreceptor was prepared in the same manner as in Example 1 except that 2.50 g was mixed with 1130 g of tetrahydrofuran and dissolved, and a charge transport layer coating solution containing no filler particles was used.

(Comparative Example 10)
Instead of the secondary dispersion coating solution for the charge transport layer, 100 g of a butadiene compound (trade name: T-405, manufactured by Takasago Fragrance Co., Ltd.) represented by the above structural formula (4) as a charge transport material and a polycarbonate resin (trade name: TS2050 (manufactured by Teijin Chemicals Ltd.) 180 g of tetrahydrofuran is mixed with 1130 g of tetrahydrofuran and dissolved in a layered photoreceptor in the same manner as in Example 1 except that a coating solution for a charge transport layer containing no filler particles and diamine compound is used. Was made.

For Examples 1 to 18 and Comparative Examples 1 to 10, the properties of the filler particles and the charge transport material (CTM) used are shown in Table 4, respectively.
In addition, since the uniform dispersion state was confirmed in the present Example, average filler particle distance a (nm) was computed from the addition amount of the filler particle, and the volume of the coating film which is a medium.
Since commercially available filler particles were used, the average filler particle diameter b (nm) and the filler particle density d (g / cm ³ ) were quoted from the catalog values.
The average density dm (g / cm ³ ) of the solid content in the outermost surface layer was calculated from the volume of the coating film and its weight. The result of calculating (df × b ³ ) / (dm × a ³ ) using the above values was defined as Rf.

For the photoconductors of Examples 1 to 18 and Comparative Examples 1 to 10 produced as described above, sensitivity (electrical characteristics), printing durability, and images were evaluated as follows, and comprehensively based on these results. Judgment was made.
That is, the digital copying machine (model: MX-2300, manufactured by Sharp Corporation) in which the photoconductors of Examples 1 to 18 and Comparative Examples 1 to 10 were modified for testing so that the developing device and the surface potential measuring device could be replaced. A surface potentiometer (trade name: model 344, manufactured by Trek Japan Co., Ltd.) is provided so that the surface potential of the photosensitive member can be measured in the image forming process, and 100,000 character test charts defined by ISO 19752 are provided. (100k) The sensitivity was evaluated by the following method by forming an image.

[Sensitivity (electric property) evaluation]
Using the above-mentioned copying machine, in a low temperature / low humidity (L / L) environment at a temperature of 5 ° C. and a relative humidity of 20%, and at a high temperature / high humidity (H / H: 35 ° C. and a relative humidity of 85%). In a High Temperature / High Humidity environment, the surface potential VL (V) immediately after exposure by laser light was measured. Next, the surface potential after forming an image of 100,000 sheets with the copying machine was measured, and the difference from VL was defined as an exposure potential difference ΔVL. The smaller the absolute value of ΔVL, the better the stability of sensitivity.

<Criteria>
A: | ΔVL | <60 (V)
○: 60 (V) ≦ | ΔVL | <70 (V)
×: 70 (V) ≦ | ΔVL |

[Evaluation of printing durability]
The cleaning blade of the cleaning device provided in the copying machine adjusts the pressure abutting on the photoreceptor, so-called cleaning blade pressure, to 21 gf / cm (2.06 × 10 ⁻¹ N / cm: initial linear pressure) as an initial linear pressure. . In a normal temperature / normal humidity (N / N) environment at a temperature of 25 ° C. and a relative humidity of 50%, the above-mentioned character test chart is formed on 100,000 sheets of recording paper for each photoconductor, and an image of 100,000 sheets The thickness of the photosensitive layer after formation was measured using a film thickness measuring device (trade name: F-20-EXR, manufactured by Filmetrics).
From the difference between the film thickness at the start of the printing durability test and the film thickness after 100,000 sheets of images were formed, the amount of abrasion per 100,000 revolutions of the photosensitive drum was determined. The printing durability was evaluated based on the following criteria based on the obtained scraping amount. It was evaluated that the greater the amount of shaving, the worse the printing durability.

<Criteria>
A: Cutting amount d <1.5 μm / 100 k rotation ○: 1.5 μm / 100 k rotation ≦ Scraping amount d <2.0 μm / 100 k rotation ×: 2.0 μm / 100 k rotation ≦ Scraping amount d

[Image evaluation (gas resistance judgment)]
In order to investigate the level of image quality degradation after the printing durability test, the image quality was evaluated by the following method.
The photoconductors of Examples 1 to 18 and Comparative Examples 1 to 10 were mounted on a digital copying machine (model: MX-2300, manufactured by Sharp Corporation), and the temperature / humidity was 35 ° C. and the relative humidity was 85% (high humidity). In an H / H) environment, 10,000 character test charts stipulated in ISO 19752 were imaged and left for 15 hours, then the test chart was printed again, and the formed image was visually observed. Based on the criteria of the evaluation.

<Criteria>
A: Image flow does not occur visually. Good picture.
○: Slight image flow occurred visually. There is no problem in actual use.
X: Image flow occurred visually. A level that causes problems in actual use.

[Comprehensive evaluation]
Based on the determination results of the above five items, comprehensive evaluation was made based on the following criteria.
◎: All four items ○
○: At least one ○
×: At least one or more ×
The above evaluation results are shown in Table 5.

  The photoreceptors of Examples 1 to 18 containing filler particles in the charge transport layer in a dispersed state satisfying the condition of the formula (1) are filled in the charge transport layer in a dispersed state not satisfying the condition of the formula (1). Compared to the photoreceptors of Comparative Examples 1 to 4 containing particles, the average scraping amount during actual copying of 100,000 sheets is 1.5 μm or less, shows good printing durability, and the electrical stability in practical use It turns out that it is a level without a problem. It can be seen that the photoreceptors of Comparative Examples 1 to 4 do not reach the desired values for sensitivity / stability or film scraping amount.

From comparison between Examples 1 to 5 and Comparative Examples 5 to 8, the photoconductor containing the diamine compound of the present invention has less film abrasion, excellent gas resistance, and good electrical property stability. I know that there is.
Further, from comparison between Example 2 and Examples 6 to 8, the ratio T / J of the weight T of the charge transport material and the weight J of the diamine compound is 100 / 0.01 or more and 100 / 20.0 or less. It can be seen that this is preferable.

From the comparison of the exposure potentials of Examples 2 and 13 to 15 and Example 12, it can be seen that silica is superior in electrical stability to alumina.
Further, from comparison between Examples 2 and 13 to 15 and Example 12, the photoreceptor using the filler particles having a small particle size is more stable in electric characteristics, and the particle size of silica to be added is 100 nm. It can be seen that the following is preferable.

  The photoreceptors of Examples 2 and 16 containing a specific nitrogen-based compound and the charge transport materials of Structural Formula (4) and Structural Formula (6) are the photoreceptors of Examples 17 and 18 that do not contain the charge transport material. As a result, it was found that the electrical characteristics after 100,000 actual shots tend to be more stable. This is presumably because these charge transport materials have further improved the resistance to gases such as ozone or nitrogen oxides generated near the charger during actual shooting.

  As described above, by incorporating a specific filler particle and a specific diamine compound in the photosensitive layer, it is excellent in mechanical / electrical durability even for long-term repeated use, and abnormal images such as image blurring. Thus, a highly durable photoconductor capable of stable image output over a long period of time could be obtained.

FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of the multilayer photoconductor of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of the multilayer photoconductor of the present invention. It is a figure which shows the difference of the aggregate particle diameter by the dispersion conditions of the filler particle which is embodiment of this invention. 1 is a schematic side view illustrating a configuration of an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Photoconductor 11 Conductive support body 12 Charge generation layer 13 Charge transport layer 14 Laminated type photosensitive layer 15 Intermediate | middle layer

30 Laser printer (image forming device)
DESCRIPTION OF SYMBOLS 31 Semiconductor laser 32 Rotating polygon mirror 34 Imaging lens 35 Mirror 36 Corona charger 37 Developing device 38 Transfer paper cassette 39 Paper feed roller 40 Registration roller

DESCRIPTION OF SYMBOLS 41 Transfer charging device 42 Separation charging device 43 Conveying belt 44 Fixing device 45 Paper discharge tray 46 Cleaner 47 Arrow 48 Transfer paper 49 Exposure means 50 Electric discharger 51 Lubricant coating device 52 Transfer device

Claims (9)

Electrons obtained by laminating a multilayer photosensitive layer in which a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material are laminated in this order on a conductive support made of a conductive material. A photographic photoreceptor, wherein the outermost surface layer of the electrophotographic photoreceptor is filler particles,
Formula (I):
[Where:
Ar ¹ , Ar ² , Ar ³ and Ar ⁴ are the same or different and each may have an aryl group which may have a substituent, a cycloalkyl group which may have a substituent, or a hetero which may have a substituent. A monovalent heterocyclic residue optionally having an atom-containing cycloalkyl group or a substituent;
^{Y 1, Y 2, Y 3} , Y 4, Y 5 and Y ⁶ are the same or different, have a good chain alkylene group which may have a substituent;
Z represents i) —Ar ⁵ —, ii) —Ar ⁵ —Ar ⁶ — or ii) —Ar ⁵ —W—Ar ⁶ — (wherein Ar ⁵ and Ar ⁶ are the same or different and each represents a substituent). An arylene group which may have or a divalent heterocyclic residue which may have a substituent; W is a cycloalkylidene group which may have a substituent, a chain which may have a substituent Or a branched alkylene group, an oxygen atom or a sulfur atom)
A diamine compound represented by
The filler particles are represented by the following formula (1):
1.0 × 10 ⁻³ ≦ (df × b ³ ) / (dm × a ³ ) ≦ 2.5 × 10 ⁻² (1)
(Wherein, a means the average distance between filler particles (nm), b means the average filler particle diameter (nm), df means the density of filler particles (g / cm ³ ), Meaning the average density (g / cm ³ ) of the solid content in the outermost surface layer)
An electrophotographic photosensitive member characterized by being contained in the outermost surface layer in a dispersed state satisfying the above. The diamine compound is a sub-formula (II):
(Wherein Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Y ⁵ , Y ⁶ and Z are as defined in formula (I); n, m, l and p are the same or different and (It is an integer of 3)
The electrophotographic photosensitive member according to claim 1, which is represented by: The diamine compound is a sub-formula (III):
(In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ have the same meanings as those in the general formula (I)).
The electrophotographic photosensitive member according to claim 2, which is represented by:   The ratio T / J between the weight T of the charge transport material and the weight J of the diamine compound in the charge transport layer is 100 / 0.01 or more and 100 / 20.0 or less. The electrophotographic photoreceptor described in 1.   The electrophotographic photosensitive member according to claim 1, wherein the filler particles are made of silicon oxide.   The electrophotographic photosensitive member according to claim 1, wherein the filler particles have an average particle diameter of 100 nm or less. The charge transport layer has the general formula (IV)
Wherein R ₁ and R ₂ are the same or different and are a lower alkyl group, or R ₁ and R ₂ may be bonded to each other to form a heterocyclic group containing a nitrogen atom; Is an integer of 1 to 4, Ar is an aromatic ring group having a butadiene group)
The electrophotographic photosensitive member according to claim 1, further comprising an amine compound represented by the formula:   The electrophotographic photosensitive member according to claim 1, further comprising an intermediate layer between the conductive support and the laminated photosensitive layer.   9. The electrophotographic photosensitive member according to claim 1, a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member, and exposure. An image forming apparatus comprising: a developing unit that develops the electrostatic latent image formed by the transfer unit; and a transfer unit that transfers the electrostatic latent image to a transfer material.