JP2006285034A - Electrophotographic photoreceptor and image forming apparatus equipped with same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor excellent in electrical properties such as charging property, sensitivity and optical responsiveness, excellent in oxidizing gas resistance, and free of deterioration of properties even if exposed to oxidizing gases such as ozone and NOx. <P>SOLUTION: A charge transport layer of an electrophotographic photoreceptor is composed of a first charge transport layer and a second charge transport layer, an enamine compound is incorporated into the first charge transport layer stacked on a charge generating layer, and a styryl-based compound is incorporated into the second charge transport layer stacked on the first charge transport layer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In an electrophotographic image forming apparatus (hereinafter also referred to as an electrophotographic apparatus) that is frequently used as a copying machine, a printer, a facsimile machine, and the like, an image is formed through the following electrophotographic process. First, a photosensitive layer of an electrophotographic photosensitive member (hereinafter also simply referred to as a photosensitive member) provided in the apparatus is uniformly charged to a predetermined potential by a charger, and exposed by irradiating light according to image information from an exposure unit. Then, an electrostatic latent image is formed. The developer is supplied from the developing means to the surface of the photoreceptor on which the electrostatic latent image is formed, and the toner as a component of the developer is adhered to develop the electrostatic latent image, and the toner image that is a visible image is formed. Form. The formed toner image is transferred from the surface of the photoreceptor to a transfer material such as recording paper by a transfer unit, and fixed by a fixing unit. The surface of the photoconductor after the toner image is transferred is cleaned by a cleaning unit, and the toner remaining on the photoconductor surface without being transferred onto the transfer material and the recording paper remaining on the photoconductor surface during transfer Foreign matter such as paper dust is removed. Thereafter, the surface charge of the photoreceptor is neutralized by a static eliminator or the like, and the electrostatic latent image disappears.

  An electrophotographic photoreceptor used in such an electrophotographic process is formed by laminating a photosensitive layer containing a photoconductive material on a conductive support. Conventionally, an electrophotographic photoreceptor using an inorganic photoconductive material (hereinafter referred to as an inorganic photoreceptor) has been used as the electrophotographic photoreceptor. As a typical inorganic photoreceptor, a selenium photoreceptor using a layer made of amorphous selenium (a-Se) or amorphous selenium arsenide (a-AsSe) as a photosensitive layer, zinc oxide (chemical formula: ZnO) Alternatively, a layer made of zinc oxide-based or cadmium sulfide-based photoconductor, amorphous silicon (a-Si) using a cadmium sulfide (chemical formula: CdS) dispersed in a resin together with a sensitizer such as a dye as a photosensitive layer. There is an amorphous silicon photoconductor (hereinafter referred to as a-Si photoconductor) used for the photosensitive layer.

  However, the inorganic photoreceptor has the following problems. For example, selenium photoreceptors and cadmium sulfide photoreceptors have problems with heat resistance and storage stability. In addition, 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. In addition, zinc oxide photoreceptors have the disadvantages of low sensitivity and low durability, and are rarely used at present. In addition, a-Si photoreceptors that are attracting attention as non-polluting inorganic photoreceptors have advantages such as high sensitivity and high durability, but use a plasma chemical vapor deposition (abbreviated CVD) method. Therefore, it is difficult to uniformly form a photosensitive layer 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 problems with inorganic photoreceptors, development of photoconductive materials used in electrophotographic photoreceptors has progressed, and instead of the conventionally used inorganic photoconductive materials, Organic photoconductive materials, that is, organic photoconductors (abbreviated as OPC), are widely used. An electrophotographic photoreceptor using an organic photoconductive material (hereinafter referred to as an organic photoreceptor) has some problems in sensitivity, durability, and environmental stability, but is toxic, manufacturing cost and material design. In terms of the degree of freedom, there are many advantages over inorganic photoreceptors. 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. Because of these many advantages, organic photoreceptors are gradually becoming the mainstream of electrophotographic photoreceptors. Also, due to recent research and development, the sensitivity and durability of organic photoreceptors have been improved, and at present, organic photoreceptors have been used as electrophotographic photoreceptors except in special cases. Yes.

  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. In addition to the above-mentioned advantages of the organic photoconductor, the function-separated type photoconductor has an advantage that a photoconductor having an arbitrary characteristic can be relatively easily manufactured with a wide selection range of materials constituting the photosensitive layer. ing.

  There are two types of function-separated type photoconductors: a multilayer type and a single-layer type. In a multi-layer type function-separated type photoconductor, a charge generation layer containing a charge generation material responsible for charge generation and a charge transport responsible for charge transport A laminated photosensitive layer is provided by laminating a charge transport layer containing a substance. The charge generation layer and the charge transport layer are each formed in a form in which a charge generation material or a charge transport material is dispersed in a binder resin as a binder. In addition, in the 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.

  Various substances such as phthalocyanine pigments, squarylium dyes, azo pigments, perylene pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes and pyrylium salt dyes are considered as charge generating materials used in functionally separated photoconductors. Various materials have been proposed that have high light resistance and excellent charge generation capability.

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

Charge transport materials include
(1) being stable to light and heat;
(2) Stable against active substances such as ozone, nitrogen gas (chemical formula: NOx) and other oxidizing gases, nitric acid, etc. generated by corona discharge when charging the photoconductor;
(3) having an excellent charge transporting ability;
(4) Excellent compatibility with organic solvents and binder resins,
(5) It must be easy and inexpensive to manufacture. However, the charge transport materials disclosed in Patent Documents 1 to 9 and the like described above satisfy some of these requirements, but have not yet satisfied all of them at a high level.

  In recent years, in response to demands for miniaturization and high speed of electrophotographic apparatuses such as digital copying machines and printers, there has been a demand for higher sensitivity of photoconductors, and there is a demand for improvement in charge transport capability of charge transport materials. Has been. In a high-speed electrophotographic process, since the time from exposure to development is short, a photoconductor excellent in photoresponsiveness is required. If the photosensitivity of the photoconductor is poor, that is, if the decay rate of the surface potential after exposure is slow, the residual potential rises and the photoconductor is repeatedly used in a state where the surface potential of the photoconductor is not sufficiently attenuated. The surface potential of the portion to be attenuated is not sufficiently attenuated by exposure, and there is a problem that the image quality is deteriorated at an early stage. In the function-separated type photoconductor, the charge generated in the charge generation material by light absorption is transported to the surface of the photoconductor by the charge transport material, thereby erasing the surface charge of the photoirradiated portion of the photoconductor. Since the potential is attenuated, the photoresponsiveness depends on the charge transporting ability of the charge transporting substance. Therefore, in order to realize a photoconductor having sufficient photoresponsiveness, an improvement in charge transport capability of the charge transport material is required.

  From such a demand, an enamine compound having a specific structure has been proposed as a charge transport material having a charge transport capability higher than that disclosed in the above-mentioned Patent Documents 1 to 9 (for example, Patent Documents). 10, 11, 12, and 13).

Japanese Patent Publication No.52-4188 JP-A-54-150128 Japanese Patent Publication No.55-42380 JP-A-55-52063 Japanese Patent Publication No.58-32372 JP 54-151955 A JP 58-198043 A JP-A-2-190862 JP 7-48324 A Japanese Patent Laid-Open No. 2-51162 Japanese Patent Laid-Open No. 6-43674 Japanese Patent Laid-Open No. 10-69107 JP-A-7-134430

  Although the photoconductor using the enamine compound disclosed in Patent Documents 10 to 13 is excellent in electrical characteristics such as photoresponsiveness, it has the following problems. The charge transport layer containing the enamine compound disclosed in Patent Documents 10 to 13 and the like described above is ozone released from a corona discharge charger (hereinafter referred to as a corona discharge charger) used as a charging means in a charging process. In addition, the emitted ozone is disadvantageous in that it is vulnerable to oxidizing gases such as nitrogen oxides produced by reacting with nitrogen in the air. For this reason, when a charge transport layer containing an enamine compound is used as the surface layer of the photoreceptor, the surface of the photoreceptor is oxidized by an oxidizing gas such as ozone remaining around the corona discharge charger, particularly when the image forming apparatus is stopped. In addition, the material constituting the photosensitive layer is oxidized, and the photoreceptor is damaged such as a decrease in surface resistance. When the surface resistance of the photoreceptor decreases, the chargeability of the photoreceptor changes, which causes a problem that image defects such as white spots and black bands occur. Here, the white spot is a phenomenon in which a portion where the toner is not attached is generated in a portion where the toner is to be attached. Further, the black belt is a phenomenon in which a portion where the toner adheres in a band shape occurs between the portion where the toner should adhere and the other portion.

  The object of the present invention is to have excellent electrical characteristics such as chargeability, sensitivity and photoresponsiveness in various environments, as well as excellent oxidation gas resistance, and is exposed to oxidizing gases such as ozone and nitrogen oxides. It is another object of the present invention to provide an electrophotographic photosensitive member whose characteristics are not deteriorated and an image forming apparatus including the same.

The present invention is an electrophotographic photosensitive member in which a charge generation layer, a first charge transport layer, and a second charge transport layer are sequentially laminated on a conductive support,
The first charge transport layer contains an enamine compound represented by the following general formula (1),
The second charge transport layer is an electrophotographic photosensitive member containing a styryl compound represented by the following general formula (2).

[Wherein, Ar ¹ and Ar ² each represents an aryl group or a heterocyclic group which may have a substituent. Ar ³ represents an aryl group, heterocyclic group, aralkyl group or alkyl group which may have a substituent. R is a divalent aromatic ring group or heterocyclic group, or group = CAr ⁴ Ar ⁵ (Ar ⁴ and Ar ⁵ each may have a hydrogen atom or a substituent, aryl group, heterocyclic group, aralkyl group Or an alkyl group, provided that Ar ⁴ and Ar ⁵ are not hydrogen atoms at the same time. R ¹ represents a hydrogen atom, a halogen atom or an alkyl group which may have a substituent. R ² , R ³ and R ⁴ each represent a hydrogen atom or an optionally substituted alkyl group, aryl group, heterocyclic group or aralkyl group. n represents an integer of 0 to 3. When there are a plurality of R ² and R ³ groups, the plurality of R ² groups may be the same or different, and the plurality of R ³ groups may be the same or different. R ⁵ represents a hydrogen atom, a halogen atom or an optionally substituted alkyl group, alkoxy group, dialkylamino group or aryl group. l shows the integer of 1-6. When R ⁵ is in plurality, a plurality of R ⁵ may be different well or be the same, or may form a divalent condensed cyclic group with a naphthylene group which they are attached. ]

[In the formula, Ar ⁶ represents an aryl group which may have a substituent. Ar ⁷ represents a hydrogen atom or an alkyl group or an aryl group which may have a substituent. Ar ⁸ represents a phenylene group, a naphthylene group, a biphenylene group or an anthrylene group which may have a substituent. R ⁶ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Ar ⁹ is an aryl group which may have a substituent or the general formula (3)

(In the formula, R ⁷ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms). ]

  The present invention is characterized in that the enamine compound represented by the general formula (1) is an enamine compound represented by the following general formula (1a).

[Wherein, Ar ⁴ , Ar ⁵ , R ⁵ and l have the same definitions as in general formula (1). m represents 1 or 2. R ⁸ , R ⁹ and R ¹⁰ each represent a hydrogen atom, a halogen atom or an optionally substituted alkyl group, alkoxy group, dialkylamino group or aryl group. i, j, and k each represent an integer of 1 to 5. When R ^{8, R 9} or ^{R 10} is a plurality, a plurality of ^R 8, ^{R 9} or ^{R 10} may be different well or even each same or monovalent condensed ring together with the phenyl group to which they are bonded A group may be formed. ]

  In the present invention, the enamine compound represented by the general formula (1a) is an enamine compound represented by the following general formula (1b).

[Wherein, m is as defined in the general formula (1a). R ^10a represents an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. ]

In the present invention, the styryl compound represented by the general formula (2) is represented by the general formula (2):
Ar ⁶ is a phenyl group which may have an alkyl group having 1 to 4 carbon atoms as a substituent,
Ar ⁷ is a hydrogen atom,
Ar ⁸ is a phenylene group,
R ⁶ is a hydrogen atom,
Ar ⁹ is a styryl compound having a phenyl group.

In the present invention, the second charge transport layer further contains a binder resin,
The ratio (B / A) of the weight (B) of the binder resin to the weight (A) of the styryl compound in the second charge transport layer is 2.0 or more and 6.0 or less.

In the present invention, the first charge transport layer and the second charge transport layer further contain a binder resin and at least one of an antioxidant and a light stabilizer,
The ratio W2 of the total weight of the antioxidant and / or light stabilizer to the total weight of the styryl compound and binder resin in the second charge transport layer is based on the total weight of the enamine compound and binder resin in the first charge transport layer. It is characterized by being larger than the ratio W1 of the total weight of the antioxidant and / or the light stabilizer (W2> W1).

The present invention also provides the electrophotographic photoreceptor of the present invention,
Charging means for charging the electrophotographic photosensitive member;
Exposure means for exposing a charged electrophotographic photosensitive member;
An image forming apparatus comprising: a developing unit that develops an electrostatic latent image formed by exposure.

According to the present invention, an electrophotographic photoreceptor (hereinafter, also simply referred to as a photoreceptor) is formed by sequentially laminating a charge generation layer, a first charge transport layer, and a second charge transport layer on a conductive support. The first charge transport layer contains an enamine compound represented by the general formula (1), preferably an enamine compound represented by the general formula (1a), more preferably an enamine compound represented by the general formula (1b). . The second charge transport layer is a styryl compound represented by the general formula (2), preferably phenyl in which the Ar ⁶ in the general formula (2) may have an alkyl group having 1 to 4 carbon atoms as a substituent. And a styryl compound in which Ar ⁷ is a hydrogen atom, Ar ⁸ is a phenylene group, R ⁶ is a hydrogen atom, and Ar ⁹ is a phenyl group.

  The enamine compound represented by the general formula (1) and the styryl compound represented by the general formula (2) function as a charge transport material. By including the enamine compound represented by the general formula (1) as a charge transport material in the first charge transport layer, the first charge transport layer is excellent in electrical characteristics such as chargeability, sensitivity, and photoresponsiveness. In addition, a photoconductor excellent in environmental stability and electrical durability that can maintain electrical characteristics even when the surrounding environment such as temperature changes is realized. Further, by incorporating a styryl compound represented by the general formula (2) as a charge transport material into the second charge transport layer laminated on the first charge transport layer, the photoreceptor is ozone resistant, nitrogen oxide resistant, etc. The oxidation resistance gas resistance can be imparted. Accordingly, as described above, the first charge transport layer containing the enamine compound represented by the general formula (1) is provided by being laminated on the charge generation layer, and further laminated on the first charge transport layer to obtain the general formula (2). By providing the second charge transport layer containing the styryl compound represented by the formula, the electrical properties such as charging property, sensitivity and responsiveness, and the environmental stability and durability of these electrical properties are excellent, and oxidation resistance A highly reliable electrophotographic photosensitive member having excellent gas properties can be obtained.

  According to the invention, the ratio (B / A) of the weight (B) of the binder resin to the weight (A) of the styryl compound represented by the general formula (2) in the second charge transport layer is 2.0. It is 6.0 or less. Thus, the printing durability of the second charge transport layer can be improved without deteriorating electrical characteristics such as responsiveness. Therefore, it is possible to obtain an electrophotographic photosensitive member that has excellent electrical characteristics and oxidation-resistant gas properties, is excellent in mechanical durability, and suppresses surface abrasion and scratches due to rubbing.

  According to the invention, the first charge transport layer and the second charge transport layer contain at least one of an antioxidant and a light stabilizer. As a result, the oxidation resistance gas resistance of the photoreceptor can be improved. The ratio of the total weight of the antioxidant and / or the light stabilizer to the total weight of the styryl compound represented by the general formula (2) and the binder resin in the second charge transport layer (hereinafter referred to as the second charge transport layer). W2 is also referred to as a ratio of the antioxidant and / or the light stabilizer). The antioxidant and / or the light stabilizer with respect to the total weight of the enamine compound represented by the general formula (1) and the binder resin in the first charge transport layer. The total weight ratio (hereinafter also referred to as the ratio of the antioxidant and / or the light stabilizer in the first charge transport layer) is greater than W1 (W2> W1). By this, the bad influence on the electrical property by adding antioxidant and / or a light stabilizer can be suppressed, and oxidation-resistant gas property can be improved efficiently. Therefore, it is possible to realize an electrophotographic photosensitive member having further excellent electric durability without deteriorating electric characteristics.

  According to the invention, the image forming apparatus includes the electrophotographic photosensitive member of the invention, a charging unit, an exposure unit, and a developing unit, the charging unit charges the electrophotographic photosensitive member of the invention, and the exposure unit exposes the image forming apparatus. Then, the electrostatic latent image formed by exposure is developed by the developing means. As described above, the electrophotographic photoreceptor of the present invention is excellent in electrical characteristics such as chargeability, sensitivity and photoresponsiveness, and environmental stability and durability of these electrical characteristics, and also in oxidation resistance gas resistance. Excellent. Therefore, by using the electrophotographic photosensitive member of the present invention, it is possible to stably provide a high-quality image free from white spots and black belts in various environments over a long period of time and to form an image with excellent reliability. A device can be obtained.

  FIG. 1 is a partial cross-sectional view showing a simplified configuration of an electrophotographic photosensitive member 1 according to an embodiment of the present invention. An electrophotographic photoreceptor (hereinafter also simply referred to as a photoreceptor) 1 includes a conductive support 11 made of a conductive material, an undercoat layer 12 laminated on the conductive support 11, and an undercoat layer 12. The charge generation layer 13 is a layer that is stacked and contains a charge generation material, and a charge transport layer 16 that is a layer that is further stacked on the charge generation layer 13 and contains a charge transport material. The charge generation layer 13 and the charge transport layer 16 constitute a photosensitive layer 17. That is, the photoreceptor 1 is a laminated photoreceptor.

  The charge transport layer 16 includes at least two layers. In the present embodiment, the charge transport layer 16 includes a first charge transport layer 14 provided in contact with the charge generation layer 12 and a second charge transport provided in contact with the first charge transport layer 14 and facing outward. It includes two layers with layer 15. That is, the first charge transport layer 14 and the second charge transport layer 15 are stacked on the charge generation layer 13 in this order.

In this embodiment, the conductive support 11 has a cylindrical shape. The conductive support 11 includes (a) a metal material such as aluminum, stainless steel, copper, nickel, (b) a surface of an insulating substance such as a polyester film, a phenol resin pipe, a paper tube, aluminum, copper, palladium, Those provided with a layer made of a conductive material such as tin oxide and indium oxide are preferably used. Among them, those having a volume resistance of 10 ¹⁰ Ω · cm or less are preferable. The conductive support 11 may be oxidized on the surface for the purpose of adjusting the volume resistance.

  The conductive support 11 serves as an electrode of the photoreceptor 1 and also functions as a support member for the other layers 12, 13, 14, and 15. The shape of the conductive support 11 is a cylindrical shape in the present embodiment, but is not limited thereto, and may be a plate shape, a sheet shape, a film shape, or a belt shape.

  The undercoat layer 12 serves as an adhesive layer between the conductive support 11 and the photosensitive layer 17 and also functions as a barrier layer that suppresses the flow of electric charge from the conductive support 11 to the photosensitive layer 17. . Therefore, the provision of the undercoat layer 12 can suppress the inflow of charges from the conductive support 11 to the photosensitive layer 17 and maintain the charging characteristics of the photosensitive member 1, thereby extending the life of the photosensitive member 1. Can do.

  The undercoat layer 12 is formed of a resin material such as polyamide, polyurethane, cellulose, nitrocellulose, polyvinyl alcohol, polyvinyl pyrrolidone, polyacrylamide, gelatin, starch, casein, or N-methoxymethylated nylon. Further, when the conductive support 11 is made of aluminum or made of an insulating material having an aluminum layer formed on the surface, an aluminum anodic oxide film can be used as the undercoat layer 12. In the undercoat layer 12, metal oxide particles such as titanium oxide, tin oxide, and aluminum oxide may be dispersed for the purpose of adjusting the volume resistance value. The thickness of the undercoat layer 12 is preferably 0.1 μm or more and 10 μm or less. When the thickness of the undercoat layer 12 is less than 0.1 μm, the effect of providing the undercoat layer 12 is not sufficiently exerted, and charge flows from the conductive support 11 into the photosensitive layer 17 to charge the photoreceptor 1. May deteriorate. If the thickness of the undercoat layer 12 exceeds 10 μm, the sensitivity of the photoreceptor 1 may be lowered.

  The charge generation layer 13 can be configured to include a known charge generation material. Any material may be used as the charge generation material as long as it absorbs light and generates free charge, and examples thereof include inorganic pigments, organic pigments, and organic dyes. Examples of inorganic pigments include selenium and its alloys, arsenic-selenium, cadmium sulfide, zinc oxide, amorphous silicon, and other inorganic photoconductors. Examples of organic pigments include phthalocyanine compounds, azo compounds, quinacridone compounds, polycyclic quinone compounds, and perylene compounds. Examples of organic dyes include thiapyrylium salts and squarylium salts. Among the aforementioned charge generating materials, organic photoconductive compounds such as organic pigments and organic dyes are preferred. Furthermore, among organic photoconductive compounds, phthalocyanine compounds are preferably used, and it is particularly preferable to use a titanyl phthalocyanine compound represented by the following general formula (4). By using a titanyl phthalocyanine compound represented by the following general formula (4), the sensitivity and chargeability of the photoreceptor 1 are improved, and the photoreceptor 1 excellent in image reproducibility is realized.

In the general formula (4), R ²¹ , R ²² , R ²³ and R ²⁴ each represent a hydrogen atom, a halogen atom, an alkyl group or an alkoxy group. r, s, y and z each represent an integer of 1 to 4. Examples of the halogen atom represented by R ²¹ , R ²² , R ^23, or R ²⁴ include a fluorine atom, a chlorine atom, and a bromine atom, and among these, a fluorine atom and a chlorine atom are preferable. Examples of the alkyl group include linear alkyl groups such as methyl group, ethyl group, n-propyl group, and n-butyl group, and branched alkyl groups such as isopropyl group and t-butyl group. An alkyl group having 1 to 4 carbon atoms is preferred. Examples of the alkoxy group include linear alkoxy groups such as methoxy group, ethoxy group and n-propoxy group, and branched chain alkoxy groups such as isopropoxy group. Among these, alkoxy groups having 1 to 4 carbon atoms are exemplified. preferable.

The titanyl phthalocyanine compound represented by the general formula (4) is, for example, Moser (
“Phthalocyanine” by Moser and Thomas
The compound can be produced by a conventionally known production method such as the method described in “Compounds”). For example, among the titanyl phthalocyanine compounds represented by the general formula (4), titanyl phthalocyanine in which R ²¹ , R ²² , R ²³ and R ²⁴ are all hydrogen atoms heats and melts phthalonitrile and titanium tetrachloride. Alternatively, dichlorotitanium phthalocyanine is synthesized by heating in a suitable solvent such as α-chloronaphthalene and then hydrolyzed with a base or water. Alternatively, titanyl phthalocyanine can be produced by reacting isoindoline with titanium tetraalkoxide such as tetrabutoxytitanium in a suitable solvent such as N-methylpyrrolidone.

  In addition to the above-described charge generation material, a sensitizer such as a chemical sensitizer and an optical sensitizer may be added to the charge generation layer 13. Chemical sensitizers include electron accepting substances, specifically, cyano compounds such as tetracyanoethylene, 7,7,8,8-tetracyanoquinodimethane, quinones such as anthraquinone and p-benzoquinone, 2 , 4,7-trinitrofluorenone, nitro compounds such as 2,4,5,7-tetranitrofluorenone and the like. Examples of the optical sensitizer include dyes such as xanthene dyes, thiazine dyes, and triphenylmethane dyes.

  For the formation of the charge generation layer 13, a vapor deposition method such as a vacuum evaporation method, a sputtering method, a CVD method or a coating method can be applied. Among these, a coating method is preferably used. When using the coating method, prepare the coating solution for the charge generation layer by dispersing the charge generation material in an appropriate solvent and adding the sensitizer and binder resin as binder as necessary. Then, the obtained coating solution is applied onto the undercoat layer 12 by a known method such as a dip coating method, and dried or cured to form the charge generation layer 13. The charge generation material may be pulverized in advance by a pulverizer before being dispersed in the solvent. Examples of the pulverizer include a ball mill, a sand grinder, a paint shaker, and an ultrasonic disperser.

  In the coating method, as the binder resin added to the coating solution, a binder resin having a binding property is used. Specific examples include polyarylate, polyvinyl butyral, polycarbonate, polyester, polystyrene, polyvinyl chloride, phenoxy resin, epoxy resin, silicone resin, and polyacrylate.

  Solvents for coating solution include alcohols such as isopropyl alcohol, ketones such as cyclohexanone, acetone and methyl ethyl ketone, aliphatic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as toluene and xylene, tetrahydrofuran, dioxane, dioxolane, etc. Ethers, ethyl cellosolve, ethylene glycol dimethyl ether, ethylene glycol alkyl ethers such as 1,2-dimethoxyethane, esters such as ethyl acetate and methyl acetate, halogenated hydrocarbons such as dichloromethane, dichloroethane and monochlorobenzene, N , N-dimethylformamide, amides such as N, N-dimethylacetamide, and the like. One of these solvents may be used alone, or two or more thereof may be used in combination.

  In the case of using an inorganic pigment or an organic pigment that easily undergoes a crystal transition as the charge generation material, the above-mentioned solvents are used in order to prevent a decrease in sensitivity due to the crystal transition during grinding and milling of the charge generation material and a decrease in characteristics due to pot life. Among these, it is preferable to use any of cyclohexanone, 1,2-dimethoxyethane, methyl ethyl ketone and tetrahydroquinone, or a mixed solvent thereof.

  When the conductive support 11 on which the undercoat layer 12 is formed is cylindrical, a spray method, a vertical ring method, a dip coating method, or the like can be used for coating the coating liquid. When the conductive support 11 on which the undercoat layer 12 is formed has a plate shape, a sheet shape, or a film shape, the coating solution can be applied using a baker applicator, a bar coater, a casting, a spin coater, or the like. .

  The thickness of the charge generation layer 13 is preferably 0.05 μm or more and 5 μm or less, and more preferably 0.1 μm or more and 1 μm or less. If the thickness of the charge generation layer 13 is less than 0.05 μm, the light absorption efficiency is lowered, and the sensitivity of the photoreceptor 1 may be lowered. If the thickness of the charge generation layer 13 exceeds 5 μm, the charge movement inside the charge generation layer 13 becomes a rate-determining step in the process of erasing the charge on the surface of the photosensitive layer 17 and the sensitivity of the photoreceptor 1 may be lowered.

  The charge transport layer 16 is formed by laminating the first charge transport layer 14 and the second charge transport layer 15 on the charge generation layer 13 in this order. The first charge transport layer 14 includes a charge transport material having the ability to accept and transport the charge generated by the charge generation material contained in the charge generation layer 13, and a binder resin that binds the charge transport material. Can be configured. The second charge transport layer 15 receives the charge generated by the charge generation material via the first charge transport layer 14, and has a charge transport material capable of transporting the charge transport material, and a binder resin for binding the charge transport material. Can be configured.

  The first charge transport layer 14 provided in contact with the charge generation layer 13 contains an enamine compound represented by the following general formula (1) as a charge transport material.

[Wherein, Ar ¹ and Ar ² each represents an aryl group or a heterocyclic group which may have a substituent. Ar ³ represents an aryl group, heterocyclic group, aralkyl group or alkyl group which may have a substituent. R is a divalent aromatic ring group or heterocyclic group, or group = CAr ⁴ Ar ⁵ (Ar ⁴ and Ar ⁵ each may have a hydrogen atom or a substituent, aryl group, heterocyclic group, aralkyl group Or an alkyl group, provided that Ar ⁴ and Ar ⁵ are not hydrogen atoms at the same time. R ¹ represents a hydrogen atom, a halogen atom or an alkyl group which may have a substituent. R ² , R ³ and R ⁴ each represent a hydrogen atom or an optionally substituted alkyl group, aryl group, heterocyclic group or aralkyl group. n represents an integer of 0 to 3. When there are a plurality of R ² and R ³ groups, the plurality of R ² groups may be the same or different, and the plurality of R ³ groups may be the same or different. R ⁵ represents a hydrogen atom, a halogen atom or an optionally substituted alkyl group, alkoxy group, dialkylamino group or aryl group. l shows the integer of 1-6. When R ⁵ is in plurality, a plurality of R ⁵ may be different well or be the same, or may form a divalent condensed cyclic group with a naphthylene group which they are attached. ]

  The enamine compound represented by the general formula (1) is excellent in charge transport ability, particularly hole transport ability. Therefore, by incorporating the enamine compound represented by the general formula (1) in the first charge transport layer 14 as a charge transport material, it is possible to realize the photoreceptor 1 having high sensitivity and excellent photoresponsiveness and chargeability. it can. Such good electrical characteristics of the photoconductor 1 are maintained even when the environment around the photoconductor 1, for example, humidity or temperature changes, and deteriorates even after the photoconductor 1 is repeatedly used. Maintained.

  However, if the charge transport layer 16 is formed in a single layer and the charge transport layer contains the enamine compound represented by the general formula (1), the surface resistance of the photoreceptor gradually decreases due to repeated use. This causes a problem that image defects such as white spots and black belts occur in the image. This is because the charge transport layer containing the enamine compound represented by the general formula (1) serves as the surface layer of the photoreceptor, and therefore, oxidizing properties such as ozone and nitrogen oxides (NOx) generated by corona discharge during charging. This is considered to be because the enamine compound represented by the general formula (1) is oxidized by the gas and the surface resistance of the photoreceptor is lowered.

  Therefore, in the present embodiment, the charge transport layer 16 is formed of two layers of the first charge transport layer 14 and the second charge transport layer 15, and the first charge transport layer 14 provided in contact with the charge generation layer 13. A styryl compound represented by the following general formula (2) is used as the charge transport material of the second charge transport layer 15 provided facing the outside, using the enamine compound represented by the general formula (1) as the charge transport material. It was decided to use.

[In the formula, Ar ⁶ represents an aryl group which may have a substituent. Ar ⁷ represents a hydrogen atom or an alkyl group or an aryl group which may have a substituent. Ar ⁸ represents a phenylene group, a naphthylene group, a biphenylene group or an anthrylene group which may have a substituent. R ⁶ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Ar ⁹ is an aryl group which may have a substituent or the general formula (3)

(In the formula, R ⁷ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms). ]

  By using the styryl compound represented by the general formula (2) as the charge transport material of the second charge transport layer 15, the photoreceptor 1 is imparted with oxidation resistance gas resistance such as ozone resistance and nitrogen oxide resistance. be able to. This is presumably because the styryl-based compound represented by the general formula (2) is stable against oxidizing gas such as ozone and nitrogen oxide (NOx) generated during charging. That is, by using the styryl compound represented by the general formula (2) as the charge transport material of the second charge transport layer 15 which is the surface layer, the interaction between the oxidizing gas and the charge transport material is suppressed, It is presumed that the deterioration of the surface layer due to the oxidizing gas sometimes generated can be suppressed. As a result, it is possible to prevent the surface resistance of the photoreceptor 1 from being lowered, and thus the photoreceptor 1 that does not cause image defects such as white spots and black bands is realized.

  In this way, the charge transport layer 16 is formed of two or more layers, and the second charge transport layer 15 facing outward contains the styryl-based compound represented by the general formula (2). By providing the first charge transport layer 14 containing the enamine compound represented by the general formula (1) between the charge generation layer 13 and the charge generation layer 13, electrical characteristics such as chargeability, sensitivity, and responsiveness, and these It is possible to obtain a highly reliable photoconductor 1 that is excellent in environmental stability and durability of the electrical characteristics and excellent in oxidation resistance gas resistance.

  Hereinafter, the enamine compound represented by the general formula (1) and the styryl compound represented by the general formula (2) will be described. First, the enamine compound represented by the general formula (1) contained in the first charge transport layer 14 will be described.

In the general formula (1), examples of the aryl group represented by the symbol Ar ¹ or Ar ² include a phenyl group, a naphthyl group, a biphenylyl group, a terphenyl group, an anthryl group, and a pyrenyl group. Among these, a phenyl group , A naphthyl group and a biphenylyl group are preferable, and a phenyl group is particularly preferable.

  Examples of the substituent that these aryl groups may have include an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms) such as a methyl group, an ethyl group, an isopropyl group, an n-propyl group, and a t-butyl group. Haloalkyl groups such as trifluoromethyl group and monofluoroethyl group (preferably haloalkyl groups having 1 to 5 carbon atoms), alkenyl groups such as 2-propenyl group and styryl group, alkoxy groups such as methoxy group, ethoxy group and propoxy group (Preferably an alkoxy group having 1 to 4 carbon atoms), monoalkylamino group such as methylamino group and ethylamino group (preferably monoalkylamino group having 1 to 4 carbon atoms), dimethylamino group, diethylamino group, diisopropylamino A dialkylamino group such as a group (preferably a dialkylamino group having 2 to 8 carbon atoms), a fluorine atom, Heterocyclic groups such as halogen atoms such as elemental atoms and bromine atoms, and thienyl groups (preferably 5-membered or 6-membered monocyclic heterocycles containing at least one selected from oxygen, nitrogen and sulfur atoms as the hetero atoms. Ring groups), aryloxy groups such as phenoxy groups, arylthio groups such as phenylthio groups, and the like. Among these, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a dialkylamino group having 2 to 8 carbon atoms are preferable.

  Examples of the aryl group having these substituents include a tolyl group, a methoxyphenyl group, a phenoxyphenyl group, a p- (phenylthio) phenyl group, and a p-styrylphenyl group. When the aryl group to which these substituents are bonded is a phenyl group, these substituents are preferably substituted at the para position of the phenyl group, such as a p-tolyl group and a p-methoxyphenyl group. These substituents may form a monovalent fused ring group together with the aryl group to which they are bonded. Examples of the monovalent fused ring group include a 5,6,7,8-tetrahydro-1-naphthyl group.

In the general formula (1), the heterocyclic group represented by Ar ¹ or Ar ² includes a furyl group, a thienyl group, a thiazolyl group, a benzofuryl group, a benzothiophenyl group, a benzothiazolyl group, a benzoxazolyl group, and a carbazolyl group. Among these, at least one selected from an oxygen atom, a nitrogen atom, a sulfur atom, a selenium atom and a tellurium atom as a hetero atom, preferably at least one selected from an oxygen atom, a nitrogen atom and a sulfur atom Monocyclic or fused-ring heterocyclic groups containing are preferred. Here, the condensed cyclic heterocyclic group is a monovalent group generated from a condensed ring formed by condensation of monocyclic heterocyclic rings and a monovalent group generated from a condensed ring formed by condensation of an aromatic ring and a heterocyclic ring. That is.

  Examples of the substituent that these heterocyclic groups may have include the same substituents that the aryl group may have. Moreover, aryl groups, such as a phenyl group and a naphthyl group, are also mentioned. Among these, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a C2-C8 dialkylamino group are preferable. Examples of the heterocyclic group having a substituent include N-methylindolyl group and N-ethylcarbazolyl group.

In the general formula (1), examples of the aryl group and heterocyclic group represented by the symbol Ar ³ include the same aryl groups and heterocyclic groups represented by Ar ¹ or Ar ² described above. Examples of the substituent that each of these groups may have include the same substituents that the aryl group represented by Ar ¹ or Ar ² may have. Among them, as the substituent group of the aryl group represented by the symbol Ar ^3, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, dialkylamino group having 2 to 8 carbon atoms, A phenoxy group and a phenylthio group are preferable. Examples of the substituent group of the heterocyclic group represented by the symbol Ar ^3, alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group is preferred.

In the general formula (1), examples of the aralkyl group represented by the symbol Ar ³ include a benzyl group, a phenethyl group, a 1-naphthylmethyl group, and a 1-naphthylethyl group. Among these, an aralkyl group having 1 to 3 carbon atoms in the alkyl portion is preferable, and a benzyl group is particularly preferable. Examples of the substituent that these aralkyl groups may have include the same substituents that the aryl group represented by Ar ¹ or Ar ² may have, and among them, those having 1 to 4 carbon atoms. An alkyl group, an alkoxy group having 1 to 4 carbon atoms, and a dialkylamino group having 2 to 8 carbon atoms are preferable. Examples of the aralkyl group having a substituent include a p-methoxybenzyl group.

In the general formula (1), examples of the alkyl group represented by the symbol Ar ³ include a linear alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an n-butyl group, an isopropyl group, and a t-butyl group. Examples thereof include cycloalkyl groups such as branched alkyl groups, cyclohexyl groups, and cyclopentyl groups. Among these, linear or branched alkyl groups having 1 to 4 carbon atoms, and cycloalkyl groups having 5 to 7 carbon atoms. Are preferred, and cycloalkyl groups having 5 to 7 carbon atoms are particularly preferred. Examples of the substituent that these alkyl groups may have include the same substituents that the aryl group represented by Ar ¹ or Ar ² may have, and among them, a halogen atom and a carbon number of 1 A 4-membered alkoxy group and a 5-membered or 6-membered monocyclic heterocyclic group containing at least one selected from an oxygen atom, a nitrogen atom and a sulfur atom as a hetero atom are preferred. Examples of the alkyl group having a substituent include a haloalkyl group such as a trifluoromethyl group and a fluoromethyl group, an alkoxyalkyl group such as a 1-methoxyethyl group, a thienylalkyl group such as a 2-thienylmethyl group and a 2-thienylethyl group. Etc.

In the general formula (1), the divalent aromatic ring group represented by the symbol R is a divalent condensed cyclic aromatic ring such as a 1-indanilidene group or a 1,2,3,4-tetrahydro-1-naphthylidene group. Among them, a divalent fused cyclic aromatic ring group having 2 to 4 rings is preferable. Moreover, as a bivalent heterocyclic group, an oxygen atom, a nitrogen atom, a sulfur atom, a selenium atom, or a tellurium atom as a hetero atom such as a benzosberonylidene group or a 9-xanthenylidene group, preferably an oxygen atom, nitrogen Examples thereof include a divalent fused cyclic heterocyclic group containing at least one selected from an atom and a sulfur atom, and among them, a divalent fused cyclic heterocyclic group having 2 to 4 rings is preferable. The nitrogen atom contained in the divalent heterocyclic group may form an imino group together with a hydrogen atom, and may form an N-alkylimino group together with an alkyl group (preferably an alkyl group having 1 to 4 carbon atoms). It may be. These divalent aromatic ring groups and heterocyclic groups include an alkylene group such as a methylene group, an ethylene group and a methylmethylene group, an alkenylene group such as a vinylene group and a propenylene group, and an oxymethylene group (chemical formula: —O It may contain a divalent group such as a heteroalkylene group such as —CH ₂ —) and a heteroalkenylene group such as a thiovinylene group (chemical formula: —S—CH═CH—).

In the group represented by the symbol R in the general formula (1) = CAr ⁴ Ar ⁵ , the aryl group and the heterocyclic group represented by the symbol Ar ⁴ or Ar ⁵ include the aryl group represented by the aforementioned Ar ¹ and Ar ² and The thing similar to a heterocyclic group is mentioned. Among them, the aryl group is preferably a phenyl group. Moreover, examples of the aralkyl group and alkyl group represented by the symbols Ar ^{4 and} Ar ⁵ include the same aralkyl groups and alkyl groups represented by Ar ³ described above. Among them, the aralkyl group is preferably an aralkyl group having 1 to 3 carbon atoms in the alkyl portion, and the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms.

Examples of the substituent that each group represented by the symbol Ar ⁴ or Ar ⁵ may have include the same substituents that the aryl group represented by the aforementioned Ar ¹ or Ar ² may have. Among them, examples of the substituent of the aryl group include an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a dialkylamino group having 2 to 8 carbon atoms, and phenylthio. Group, phenoxy group and styryl group are preferred. Moreover, as a substituent which a heterocyclic group has, a C1-C4 alkyl group is preferable. Moreover, as a substituent which an alkyl group has, a thienyl group is preferable.

In the general formula (1), examples of the halogen atom represented by the symbol R ¹ include a fluorine atom, a chlorine atom, and a bromine atom. Among these, a fluorine atom and a chlorine atom are preferable. The alkyl group represented by reference numeral R ^1, include the same alkyl groups represented by Ar ³ in the above, preferably an alkyl group having 1 to 4 carbon atoms among them. Examples of the substituent that these alkyl groups may have include the same substituents that the aryl group represented by the aforementioned Ar ¹ and Ar ² may have, and among them, a halogen atom is preferable.

In the general formula (1), examples of the alkyl group and aralkyl group represented by the symbols R ² , R ^{3, and} R ⁴ include the same alkyl groups and aralkyl groups represented by Ar ³ described above. Among these, preferably an alkyl group having 1 to 4 carbon atoms as the alkyl group represented by the symbol R ^4, the aralkyl group represented by the symbol R ⁴ benzyl group is preferred. In addition, examples of the aryl group and heterocyclic group represented by the symbols R ² , R ^{3, and} R ⁴ include the same aryl groups and heterocyclic groups represented by Ar ¹ and Ar ² described above. Among these, a phenyl group is preferable as the aryl group represented by the symbol R ^4, examples of the heterocyclic group represented by the symbol R ⁴ a thienyl group is preferable. Examples of the substituent that each of these groups may have include the same substituents that the aryl group represented by Ar ¹ and Ar ² may have.

In the general formula (1), examples of the halogen atom represented by the symbol R ⁵ include the same halogen atoms as those represented by the symbol R ¹ described above. Among these, a fluorine atom and a chlorine atom are preferable. Examples of the alkyl group represented by the symbol R ⁵ include the same alkyl groups represented by the symbol Ar ³ , and among them, an alkyl group having 1 to 4 carbon atoms is preferable. Examples of the aryl group represented by the symbol R ⁵ include the same aryl groups as those represented by the aforementioned symbol Ar ¹ or Ar ² .

In the general formula (1), examples of the alkoxy group represented by the symbol R ⁵ include a linear alkoxy group such as a methoxy group, an ethoxy group, and an n-propoxy group, and a branched alkoxy group such as an isopropoxy group. Of these, an alkoxy group having 1 to 4 carbon atoms is preferable. Examples of the dialkylamino group include symmetric dialkylamino groups such as dimethylamino group, diethylamino group and diisopropylamino group, and asymmetric dialkylamino groups such as ethylmethylamino group and isopropylethylamino group. The dialkylamino group is preferred. Examples of the substituent that each of these groups may have include the same substituents that the aryl group represented by the above-mentioned symbol Ar ¹ or Ar ² may have.

In the general formula (1), when l is there are a plurality of R ⁵ be two or more, as the plurality of R ⁵ are fused ring group may divalent to optionally form together naphthylene group which these bonds, Examples include 1,2,3,4-tetrahydro-9,10-anthrylene group.

Among the enamine compounds represented by the general formula (1), as a preferable compound, in the general formula (1), one of R ² and R ³ is a hydrogen atom, and the other is a hydrogen atom, a thienyl group, a benzyl group or The enamine compound which is a C1-C4 alkyl group which may have 1 type, or 2 or more types chosen from a halogen atom and a C1-C4 alkoxy group as a substituent is mentioned.
Among these enamine compounds, more preferred compounds are those represented by the general formula (1a)

[Wherein, Ar ⁴ , Ar ⁵ , R ⁵ and l have the same definitions as in general formula (1). m represents 1 or 2. R ⁸ , R ⁹ and R ¹⁰ each represent a hydrogen atom, a halogen atom or an optionally substituted alkyl group, alkoxy group, dialkylamino group or aryl group. i, j, and k each represent an integer of 1 to 5. When R ^{8, R 9} or ^{R 10} is a plurality, a plurality of ^R 8, ^{R 9} or ^{R 10} may be different well or even each same or monovalent condensed ring together with the phenyl group to which they are bonded A group may be formed. The enamine compound represented by this is mentioned.

In the general formula (1a), specific examples of each group represented by the symbol R ⁸ , R ⁹ or R ¹⁰ include the same groups as those represented by the symbol R ⁵ in the general formula (1). Among them, the alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, the alkoxy group is preferably an alkoxy group having 1 to 4 carbon atoms, and the dialkylamino group is preferably a dialkylamino group having 2 to 8 carbon atoms. Moreover, as these substituents which may be possessed by each group, those similar to the substituent which may have an aryl group represented by the symbol Ar ¹ or Ar ² in the general formula (1).

In formula (1a), i is 2 or more at a plurality of R ⁸ when R ⁸ is plural and may form together with the phenyl group to these binding monovalent condensed ring group, j is a plurality of R ⁹ be two or more when R ⁹ there is a plurality may form together with the phenyl group to these binding monovalent condensed ring group or k is at least 2 R ^10, is Examples of the monovalent fused ring group that may be formed by a plurality of R ¹⁰ groups together with these bonded phenyl groups when there are a plurality of groups include a 5,6,7,8-tetrahydro-1-naphthyl group. It is done.

  Among the enamine compounds represented by the general formula (1a), particularly preferable compounds include those represented by the general formula (1b).

[Wherein, m is as defined in the general formula (1a). R ^10a represents an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. The enamine compound represented by this is mentioned.

In the general formula (1b), the alkyl group having 1 to 4 carbon atoms represented by the symbol R ^10a is a straight chain having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, or an n-butyl group. Examples thereof include a branched alkyl group having 1 to 4 carbon atoms such as an alkyl group, an isopropyl group and a t-butyl group. Moreover, as C1-C4 alkoxy group shown by code ^| symbol R10a, C1-C4 linear alkoxy groups, such as a methoxy group, an ethoxy group, n-propoxy group, carbon number, such as an isopropoxy group Examples include 1 to 4 branched chain alkoxy groups.

  The enamine compound represented by the general formula (1a), particularly the enamine compound represented by the general formula (1b) is superior in charge transporting ability and compared with the synthesis among the enamine compounds represented by the general formula (1). Therefore, it can be manufactured at a relatively low cost. Therefore, by using the enamine compound represented by the general formula (1a), preferably the enamine compound represented by the general formula (1b), the photoresponsiveness can be improved and the manufacturing cost of the photoreceptor 1 can be reduced. Can do.

  Further, among the enamine compounds represented by the general formula (1a), the enamine compound has a particularly excellent charge transport capability and can greatly contribute to the improvement of the photoresponsiveness of the photoreceptor 1, so that m is 1 in the general formula (1a). It is preferable to use an enamine compound, and it is particularly preferable to use an enamine compound in which m is 1 in the general formula (1b).

Among the enamine compounds represented by the general formula (1), as a particularly excellent compound from the viewpoint of characteristics, cost, productivity and the like, in the general formula (1), Ar ¹ and Ar ² are both phenyl groups, Ar ³ is a phenyl group, tolyl group, p-methoxyphenyl group, biphenylyl group, naphthyl group or thienyl group, and at least one of Ar ⁴ and Ar ⁵ is a phenyl group, p-tolyl group, p-methoxy group Mention may be made of an enamine compound which is a phenyl group, a naphthyl group, a thienyl group or a thiazolyl group, in which R ¹ , R ² , R ³ and R ⁴ are all hydrogen atoms and n is 1.

  Among the enamine compounds represented by the general formula (1), specific examples of the enamine compounds represented by the following general formula (1c) include the exemplified compounds shown in the following Tables 1 to 32. In Tables 1 to 32, each exemplified compound is represented by a group corresponding to each group of the general formula (1c). For example, Exemplified Compound Nos. 1 is an enamine compound represented by the following structural formula (1-1).

[Wherein, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , R ¹ , R ² , R ³ , R ⁴ , R ⁵ , n and l are as defined in the general formula (1]]. ]

However, in Tables 1 to 32, in the row where the column of Ar ^{4 and} the column of Ar ⁵ are connected to one, the enamine compound in which R is a divalent aromatic ring group or heterocyclic group in the general formula (1) Is illustrated. In this case, the substituent represented by the symbol R in the general formula (1) is shown in the column where the column of Ar ^{4 and} the column of Ar ⁵ are connected. Further, among the enamine compounds in which n is 2 or 3 in the general formula (1), a plurality of R ² groups are the same, and a plurality of R ³ groups are the same. In the example, one R ² and one R ³ are shown. The enamine compounds represented by the general formula (1) are exemplified compound Nos. 1-No. It is not limited to 220.

  The enamine compound represented by the general formula (1) can be produced, for example, as follows. First, by performing a dehydration condensation reaction between an aldehyde compound or a ketone compound represented by the following general formula (5) and a secondary amine compound represented by the following general formula (6), the following general formula (7) The enamine intermediate represented is produced.

〔式中、Ａｒ^１、Ａｒ^２およびＲ^１は一般式（１）における定義と同義である。〕

[Wherein, Ar ¹ , Ar ² and R ¹ have the same definitions as in general formula (1). ]

〔式中、Ａｒ^３、Ｒ^５およびｌは一般式（１）における定義と同義である。〕

[Wherein Ar ³ , R ⁵ and l have the same definitions as in general formula (1). ]

[Wherein, Ar ¹ , Ar ² , Ar ³ , R ¹ , R ⁵ and l have the same definitions as in general formula (1). ]

  This dehydration condensation reaction is performed, for example, as follows. In a suitable solvent, an aldehyde compound or a ketone compound represented by the general formula (5) and a secondary amine compound represented by the general formula (6) are added in approximately equimolar amounts and dissolved to prepare a solution. . Examples of the solvent used include aromatic hydrocarbons such as toluene, xylene and chlorobenzene, alcohols such as butanol, and ethers such as diethylene glycol dimethyl ether. A catalyst, for example, an acid catalyst such as p-toluenesulfonic acid, camphorsulfonic acid, pyridinium-p-toluenesulfonic acid or the like is added to the prepared solution, and the mixture is heated and reacted as necessary. It is preferable that the addition amount of a catalyst is 1/10 (1/10)-1/1000 (1/1000) molar equivalent with respect to the aldehyde compound or ketone compound represented by General formula (5). More preferably, it is 1/25 (1/25) to 1/500 (1/500) molar equivalent, and more preferably 1/50 (1/50) to 1/200 (1/200). Molar equivalent. During the reaction, water is formed as a by-product and hinders the reaction. Therefore, it is preferable to remove the produced water from the system by azeotropic distillation with a solvent. Thereby, the enamine intermediate represented by the general formula (7) can be produced in high yield.

  Next, an enamine-carbonyl intermediate represented by the following general formula (8) is produced by acylating the enamine intermediate represented by the general formula (7).

[Wherein, Ar ¹ , Ar ² , Ar ³ , R ¹ , R ⁵ and l have the same definitions as in general formula (1). R ¹¹ represents a group represented by R ² or R ⁴ in the general formula (1). ]

For example, among the enamine-carbonyl intermediates represented by the general formula (8), the enamine-aldehyde intermediate in which R ¹¹ is a hydrogen atom is obtained by converting the enamine intermediate represented by the general formula (7) by the Filsmeier reaction. It can be produced by formylation.

The Filsmeier reaction is performed, for example, as follows. In a suitable solvent, phosphorus oxychloride and N, N-dimethylformamide, N-methyl-N-phenylformamide or N, N-diphenylformamide are added to prepare a Vilsmeier reagent. Examples of the solvent used at this time include aprotic polar solvents such as N, N-dimethylformamide and halogenated hydrocarbons such as 1,2-dichloroethane. 1.0 mol equivalent of the enamine intermediate represented by the general formula (7) is added to the solution in which 1.0 to 1.3 mol equivalent of the Vilsmeier reagent is prepared, for example, 2 under heating at 60 to 110 ° C. Stir for ~ 8 hours to react. After completion of the reaction, hydrolysis is performed with an alkaline aqueous solution of 1 to 8 N (N). Examples of the alkaline aqueous solution used for the hydrolysis include a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution. As described above, among the enamine-carbonyl intermediates represented by the general formula (8), an enamine-aldehyde intermediate in which R ¹¹ is a hydrogen atom can be produced in a high yield.

Further, among the enamine-carbonyl intermediates represented by the general formula (8), the enamine-keto intermediate in which R ¹¹ is a group other than a hydrogen atom is obtained by converting the enamine compound represented by the general formula (7) to Friedel. -It can manufacture by acylating by kraft acylation reaction.

  This Friedel-Craft acylation reaction is performed as follows, for example. In a suitable solvent, add 1.0 to 1.2 molar equivalent of Lewis acid and 1.0 molar equivalent of acyl halide represented by the following general formula (9), and stir for about 0.5 to 1 hour. A Friedel-Craft acylating reagent is prepared. Examples of the solvent used at this time include halogenated hydrocarbons such as 1,2-dichloroethane and dichloromethane, and aromatic hydrocarbons such as nitrobenzene. Examples of the Lewis acid include aluminum chloride, tin chloride, and zinc chloride.

[Wherein, R ¹¹ has the same definition as in general formula (8). X ¹ represents a halogen atom. ]

In the general formula (1), examples of the halogen atom represented by the symbol X ¹ include a fluorine atom, a chlorine atom, and a bromine atom. Among these, a chlorine atom and a bromine atom are preferable.

In this way, 1.0 mol equivalent of the enamine intermediate represented by the general formula (7) is added to the solution in which 1.0 to 1.3 mol equivalent of Friedel-Craft acylating reagent is prepared. (−) The mixture is reacted at 40 to 80 ° C. with stirring for 2 to 8 hours. After completion of the reaction, hydrolysis is performed with an alkaline aqueous solution of 1 to 8 N (N). Examples of the alkaline aqueous solution used for the hydrolysis include a sodium hydroxide aqueous solution and a potassium hydroxide aqueous solution. As described above, among the enamine-carbonyl intermediates represented by the general formula (8), an enamine-keto intermediate in which R ¹¹ is a group other than a hydrogen atom can be produced in high yield.

Note that when manufacturing enamine compounds wherein n is 0 in the general formula (1), enamine represented by formula (8) - as carbonyl intermediate, to produce the compound wherein R ¹¹ is R ^4. Further, when n is manufactured enamine compound is 1 to 3 in the general formula (1), enamine represented by formula (8) - as carbonyl intermediates, making the compounds R ¹¹ is R ² To do.

  Next, a Wittig-Horner (reaction) in which an enamine-carbonyl intermediate represented by the general formula (8) is reacted with a Wittig reagent represented by the following general formula (10a) or (10b) under basic conditions ( An enamine compound represented by the general formula (1) can be produced by performing a Wittig-Horner reaction.

[Wherein, R has the same definition as in general formula (1). R ¹² represents an alkyl group or an aryl group. ]

[Wherein, R, R ² , R ³ , R ⁴ and n are as defined in the general formula (1). However, n is not 0. R ¹³ represents an alkyl group or an aryl group. ]

  The Wittig reagent represented by the general formulas (10a) and (10b) is appropriately selected and used according to the value of n in the general formula (1). For example, when an enamine compound in which n is 0 in the general formula (1) is produced, a Wittig reagent represented by the general formula (10a) is used. Moreover, when manufacturing the enamine compound whose n is 1-3 in General formula (1), the Wittig reagent represented by General formula (10b) is used.

In the general formulas (10a) and (10b), the alkyl group represented by R ¹² or R ¹³ is a linear alkyl group such as a methyl group, an ethyl group or an n-propyl group, or a branched chain such as an isopropyl group. An alkyl group etc. are mentioned, Among these, a C1-C4 alkyl group is preferable. Examples of the aryl group include a phenyl group, a naphthyl group, and a biphenylyl group. Among these, an aryl group having 1 to 3 rings is preferable, and a phenyl group is particularly preferable.

  The Wittig-Horner reaction between the enamine-carbonyl intermediate represented by the general formula (8) and the Wittig reagent represented by the general formula (10a) or (10b) is performed, for example, as follows. In a suitable solvent, 1.0 mol equivalent of the enamine-carbonyl intermediate represented by the general formula (8) and 1.0 to 1.20 mol of the Wittig reagent represented by the general formula (10a) or (10b) An equivalent amount and 1.0 to 1.5 molar equivalents of a metal alkoxide base are added and, for example, the reaction is allowed to stir for 2 to 8 hours with heating at room temperature or 30 to 60 ° C. Solvents used at this time include aromatic hydrocarbons such as toluene and xylene, ethers such as diethyl ether, tetrahydrofuran and ethylene glycol dimethyl ether, and aprotic polar solvents such as N, N-dimethylformamide and dimethyl sulfoxide. Is mentioned. Examples of the metal alkoxide base include potassium t-butoxide, sodium ethoxide, sodium methoxide and the like.

  As described above, the enamine compound represented by the general formula (1) can be produced in high yield. The enamine compound represented by the general formula (1) can be easily isolated and purified from the reaction mixture by a usual separation means such as a solvent extraction method, a recrystallization method, or column chromatography, and obtained as a high purity compound. be able to.

  The enamine compounds represented by the general formula (1) are exemplified by the exemplified compound Nos. 1-No. One selected from the group consisting of 220 may be used alone, or two or more may be used in combination.

  Next, the styryl compound represented by the general formula (2) contained in the second charge transport layer 15 will be described.

In the general formula (2), examples of the aryl group represented by the symbol Ar ⁶ include a phenyl group, a naphthyl group, a biphenylyl group, an anthryl group, and a pyrenyl group. Among these, an aryl group having 1 to 4 rings is preferable. A phenyl group is particularly preferred.

Examples of the substituent that the aryl group represented by the symbol Ar ⁶ may have include a linear alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, and an n-propyl group, an isopropyl group, and a t-butyl group. Alkyl groups such as C1-C4 branched alkyl groups having 1 to 4 carbon atoms, such as cyclopentyl groups and cyclohexyl groups, such as cycloalkyl groups having 5 to 6 carbon atoms, methoxy groups, ethoxy groups, n-propoxy groups and the like. -4 linear alkoxy groups, alkoxy groups such as C1-C4 branched alkoxy groups such as isopropoxy group, aralkyl groups such as benzyl group, aryl groups such as phenyl group, fluorine atom, chlorine atom, Examples thereof include halogen atoms such as bromine atoms, alkenyl groups such as styryl groups, vinyl groups, etc. Among these, linear or branched alkyl groups having 1 to 4 carbon atoms, carbon A cycloalkyl group having 5 to 6 primes and a halogen atom are preferred.

When the substituent that the aryl group represented by the symbol Ar ⁶ has is an alkyl group or an alkoxy group, these substituents may be further substituted with an alkoxy group having 1 to 4 carbon atoms, a halogen atom, or the like. Further, when the substituent group of the aryl group represented by the symbol Ar ⁶ is an aralkyl group or an aryl group, these substituents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom And may be further substituted.

In the general formula (2), examples of the alkyl group denoted by Ar ⁷ include a linear alkyl group such as a methyl group, an ethyl group, and an n-propyl group, a branched alkyl group such as an isopropyl group, and the like. Among these, a C1-C4 alkyl group is preferable. Examples of the aryl group represented by the symbol Ar ⁷ include the same aryl groups represented by the symbol Ar ⁶ . Examples of the substituent that each of these groups may have include the same substituents that the aryl group represented by the symbol Ar ⁶ may have. Among them, the substituent that the alkyl group has is preferably a linear or branched alkoxy group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 6 carbon atoms, or a halogen atom, and the substituent that the aryl group has Is preferably an alkyl group having 1 to 4 carbon atoms.

In the general formula (2), the substituent that the phenylene group, naphthylene group, biphenylene group, and anthrylene group represented by the symbol Ar ⁸ may have is the substituent that the aryl group represented by the symbol Ar ⁶ may have. The same thing as a group is mentioned. Among these, a C1-C4 alkyl group, a C1-C4 alkoxy group, and a halogen atom are preferable. When the substituent of the phenylene group, naphthylene group, biphenylene group or anthrylene group represented by the symbol Ar ⁸ is an alkyl group or an alkoxy group, these substituents are further substituted with an alkoxy group having 1 to 4 carbon atoms, a halogen atom, or the like. May be substituted.

In the general formula (2), the alkyl group having 1 to 4 carbon atoms represented by the symbol R ⁶ is a linear alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, or an n-propyl group, and an isopropyl group. And a branched alkyl group having 1 to 4 carbon atoms such as t-butyl group. Further, the alkoxy group having 1 to 4 carbon atoms represented by the symbol R ^6, methoxy, ethoxy, straight-chain alkoxy group having 1 to 4 carbon atoms such as n- propoxy group, carbon atoms, such as an isopropoxy group Examples include 1 to 4 branched chain alkoxy groups.

In the general formula (2), examples of the aryl group represented by the symbol Ar ⁹ include the same aryl groups represented by the symbol Ar ⁶ . Examples of the substituent that the aryl group may have include the same substituents that the aryl group denoted by Ar ⁶ may have. Among them, a linear or branched alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 6 carbon atoms, a linear or branched alkoxy group having 1 to 4 carbon atoms, a halogen atom, a benzyl group , A styryl group and a vinyl group are preferable. When the substituent that the aryl group represented by the symbol Ar ⁹ has is an alkyl group or an alkoxy group, these substituents may be further substituted with an alkoxy group having 1 to 4 carbon atoms, a halogen atom, or the like. Also when substituent group of the aryl group represented by the symbol Ar ⁹ is a vinyl group, a vinyl group may be further substituted with an aryl group such as phenyl group. At this time, the aryl group substituted on the vinyl group may be further substituted with an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or the like.

In the general formula (3) represented by the symbol Ar ⁹ in the general formula (2), the alkyl group having 1 to 4 carbon atoms and the alkoxy group having 1 to 4 carbon atoms represented by the symbol R ⁷ are represented by the symbol R ⁶ . Examples thereof include the same alkyl groups having 1 to 4 carbon atoms and alkoxy groups having 1 to 4 carbon atoms. Examples of the monovalent group represented by the general formula (3) include R ⁷ such as 5,6,7,8-tetrahydro-1-naphthyl group and 5,6,7,8-tetrahydro-2-naphthyl group. The thing which is a hydrogen atom etc. are mentioned.

Among the styryl compounds represented by the general formula (2), as a preferable compound, in the general formula (2), Ar ⁶ may be a phenyl group which may have an alkyl group having 1 to 4 carbon atoms as a substituent. A styryl compound in which Ar ⁷ is a hydrogen atom, Ar ⁸ is a phenylene group, R ⁶ is a hydrogen atom, and Ar ⁹ is a phenyl group (hereinafter referred to as a styryl compound (2a)). It is done.

  The styryl compound (2a) exhibits a particularly excellent inhibitory effect against fatigue deterioration of the photoreceptor due to an oxidizing gas. Therefore, by using the styryl compound (2a), it is possible to realize a highly reliable photoreceptor 1 that is particularly excellent in oxidation resistance gas resistance and exhibits stable electric characteristics during repeated use.

Specific examples of the styryl compound represented by the general formula (2) include those represented by the following structural formulas (2-1) to (2-70). The styryl-based compound to be used is not limited to these. In the following, t-Bu represents a t-butyl group (—C (CH ₃ ) ₃ ), and n-Bu represents an n-butyl group (—CH ₂ CH ₂ CH ₂ CH ₃ ).

  As the styryl compound represented by the general formula (2), for example, one kind selected from the group consisting of the styryl compounds represented by the structural formulas (2-1) to (2-70) is used alone. Or two or more of them may be used in combination.

  The first charge transport layer 14 may contain a charge transport material other than the enamine compound represented by the general formula (1) as long as the preferable characteristics of the present invention are not impaired. Examples of charge transport materials that can be used in combination with the enamine compound represented by the general formula (1) include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives. , Bisimidazolidine derivatives, styryl compounds, hydrazone compounds, polycyclic aromatic compounds, indole derivatives, pyrazoline derivatives, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamines Derivatives, triarylmethane derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, and the like can be given. Also included are polymers having groups derived from these compounds in the main chain or side chain, such as poly (N-vinylcarbazole), poly (1-vinylpyrene), poly (9-vinylanthracene) and the like.

  Further, the second charge transport layer 15 may contain a charge transport material other than the styryl compound represented by the general formula (2) within a range that does not impair the preferable characteristics of the present invention. Examples of the charge transport material that can be used in combination with the styryl compound represented by the general formula (2) include those exemplified as the charge transport material that can be used in combination with the enamine compound represented by the general formula (1). .

Examples of the binder resin of the first charge transport layer 14 and the second charge transport layer 15 include a vinyl polymer such as a methacryl resin such as polymethyl methacrylate resin, an acrylic resin such as polymethyl acrylate, a polystyrene resin, and a polyvinyl chloride resin. Resins and copolymer resins containing two or more of the repeating units constituting them, as well as polycarbonate resins, polyester resins, polyester carbonate resins, polysulfone resins, phenoxy resins, epoxy resins, silicone resins, polyarylate resins, polyamide resins , Polyether resin, polyurethane resin, polyacrylamide resin, phenol resin and the like. Moreover, the thermosetting resin which partially bridge | crosslinked these resin is also mentioned. One of these resins may be used alone, or two or more thereof may be used in combination. Among the resins described above, polystyrene resin, polycarbonate resin, polyarylate resin, and polyphenylene oxide have a volume resistivity of 10 ¹³ Ω · cm or more and excellent electrical insulation properties. Therefore, it is preferable to use one or more of these for the binder resin.

  The binder resin for the first charge transport layer 14 is selected from the resins described above that have excellent compatibility with the enamine compound represented by the general formula (1) used as the charge transport material. It is preferable. In addition, it is preferable to select and use a binder resin for the second charge transport layer 15 that is excellent in compatibility with the styryl compound represented by the general formula (2) used as the charge transport material.

  As a means for improving the mechanical durability of the photoreceptor 1, it is conceivable to increase the ratio of the binder resin in the charge transport layer 16. However, since the charge transport material in the charge transport layer 16 is diluted with an increase in the binder resin ratio, if the binder resin ratio is too high, the photoresponsiveness of the photoreceptor 1 is lowered and sufficient sensitivity is obtained. May not be obtained. When the photoresponsiveness of the photosensitive member 1 is lowered, the residual potential is increased, and the surface potential of the photosensitive member 1 is repeatedly used in a state where the surface potential is not sufficiently attenuated. Is not sufficiently erased, the surface potential is not sufficiently attenuated, and the image quality is deteriorated at an early stage.

  In order to improve the mechanical durability of the photoreceptor 1 without causing such a problem, the two charge transport layers 14 and 15 constituting the charge transport layer 16 are provided facing outward. The ratio of the binder resin in the second charge transport layer 15 is relatively high, and the ratio of the binder resin in the first charge transport layer 14 provided closer to the conductive support 11 than the second charge transport layer 15 is relatively It is preferable to make it low. Specifically, the ratio of the weight (B) of the binder resin to the weight (A) of the styryl compound represented by the general formula (2) contained as the charge transport material in the second charge transport layer 15 (B / A ) Of the binder resin weight (B ′) to the weight (A ′) of the enamine compound represented by the general formula (1) contained as the charge transport material in the first charge transport layer 14 (B ′ / A) It is preferable to make it larger than ').

  As described above, in the second charge transport layer 15 serving as the surface layer of the photoreceptor 1, the binder resin ratio is increased to improve the printing durability, and the second charge transport layer 15 is provided between the second charge transport layer 15 and the charge generation layer 13. In the first charge transport layer 14, the photo-responsiveness of the entire charge transport layer 16 is ensured by increasing the ratio of the enamine compound represented by the general formula (1), which is a charge transport material, to increase the hole mobility. can do. Therefore, the mechanical durability of the photoreceptor 1 can be improved without reducing the photoresponsiveness.

  In order to give sufficient printing durability to the second charge transport layer 15 and to suppress a decrease in photoresponsiveness as much as possible, the ratio B / A in the second charge transport layer 15 is 2.0 or more and 6.0. The following is preferable. When the ratio B / A exceeds 6.0 and the binder resin ratio increases, the ratio of the styryl compound represented by the general formula (2), which is a charge transport material, is relatively low, and therefore hopping conduction is reduced. It is less likely to occur and hole mobility may be reduced. If the ratio B / A is less than 2.0, the printing durability of the second charge transport layer 15 cannot be sufficiently secured, and the mechanical durability of the photoreceptor 1 may be insufficient.

  The ratio B ′ / A ′ in the first charge transport layer 14 is preferably 0.8 or more and 2.0 or less. By selecting the ratio B ′ / A ′ within the above range, the phototransport layer 16 is provided with sufficient photoresponsiveness, and the enamine compound represented by the general formula (1) in the first charge transport layer 14 Thus, the uniformity of the first charge transport layer 14 can be improved. As a result, it is possible to prevent image defects such as black spots from occurring in an image formed using the photoreceptor 1. When the ratio B ′ / A ′ exceeds 2.0 and the ratio of the binder resin is high, the ratio of the enamine compound represented by the general formula (1) to the binder resin is low, so that the hole mobility becomes slow, The photoresponsiveness of the entire charge transport layer 16 may not be sufficiently obtained. Further, when the ratio B ′ / A ′ is less than 0.8, the ratio of the charge transport material to the binder resin becomes too high, and in the process of being repeatedly used, the general formula (1 ), The crystallization of the enamine compound may occur and the image quality may be significantly reduced.

  Further, it is preferable to add at least one of an antioxidant and a light stabilizer to each layer of the charge transport layer 16, that is, the first charge transport layer 14 and the second charge transport layer 15. In particular, it is preferable to add an antioxidant and / or a light stabilizer to the second charge transport layer 15 which is the surface layer of the photoreceptor 1. As a result, deterioration of the layers 14 and 15 of the charge transport layer 16 due to an oxidizing gas such as ozone and NOx generated during charging can be reduced, and the electrical durability of the photoreceptor 1 can be further improved. In addition, since the stability of the coating liquid when forming each layer 14 and 15 by coating can be improved and the generation of impurities in the coating liquid can be prevented, the life of the coating liquid can be extended and formed. Impurities in the charge transport layers 14 and 15 can be reduced, and the electrical durability of the photoreceptor 1 can be improved.

  As the antioxidant, an antioxidant generally added to a resin or the like can be used. For example, phosphorus antioxidants such as hindered phenol compounds, trimethoxyphosphine, triphenoxyphosphine, di (n- Sulfur-based antioxidants such as octyl) sulfide, hydroquinone and its derivatives, p-phenylenediamine and its derivatives, tocopherol and its derivatives, and the like.

  Among these, hindered phenol compounds are preferably used. Here, the hindered phenol compound is a compound having a phenolic hydroxyl group (—OH) and having a bulky atomic group in the vicinity of the phenolic hydroxyl group. Examples of the bulky atomic group include a branched alkyl group, a cycloalkyl group, an aryl group, and a heterocyclic group.

  Among the hindered phenol compounds, hindered phenol compounds represented by the following general formula (11) are preferably used.

〔式中、Ｒ^１４は炭素数１〜４のアルキル基を示す。〕

[Wherein, R ¹⁴ represents an alkyl group having 1 to 4 carbon atoms. ]

In the general formula (11), the alkyl group having 1 to 4 carbon atoms represented by the symbol R ¹⁴ is a linear alkyl group having 1 to 4 carbon atoms such as a methyl group or an ethyl group, an isopropyl group, or a t-butyl group. And a branched alkyl group having 1 to 4 carbon atoms.

  As the light stabilizer, a light stabilizer that is generally added to a resin or the like can be used, and examples thereof include hindered amine compounds, benzotriazole and derivatives thereof, and benzophenone and derivatives thereof.

  Among these, hindered amine compounds are preferably used. Here, the hindered amine compound is an amine compound having an amino nitrogen atom and having a bulky atomic group in the vicinity of the amino nitrogen atom. Examples of the bulky atomic group include a branched alkyl group, a cycloalkyl group, an aryl group, and a heterocyclic group. The hindered amine compound may be either an aromatic amine type or an aliphatic amine type, but is preferably an aliphatic amine type.

  Among the hindered amine compounds, hindered amine compounds represented by the following general formula (12) are preferably used.

[Wherein, R ¹⁵ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an acyl group. R ¹⁶ and R ¹⁷ each represent an acyloxy group. In place of R ¹⁶ and R ¹⁷ , a divalent aliphatic heterocyclic group may be bonded to the carbon atom to which R ¹⁶ and R ¹⁷ are bonded. ]

In the general formula (12), the alkyl group having 1 to 4 carbon atoms represented by the symbol R ¹⁵ is a linear alkyl group having 1 to 4 carbon atoms such as a methyl group or an ethyl group, an isopropyl group, or a t-butyl group. And a branched alkyl group having 1 to 4 carbon atoms. Examples of the acyl group represented by the symbol R ¹⁵ include an acetyl group. Examples of the acyloxy group represented by the symbol R ¹⁶ or R ¹⁷ include an acetoxy group and a benzoyloxy group. Examples of the divalent aliphatic heterocyclic group which may be bonded to the carbon atom to which R ¹⁶ and R ¹⁷ are bonded include a pyrrolidinediyl group, an imidazolidinediyl group, an imidazolidinedionediyl group, a tetrahydrofurandiyl group and a dioxolanediyl group. And piperidinediyl group. Each of these groups may have a substituent such as an alkyl group.

  Specific examples of the hindered amine compound represented by the general formula (12) include a hindered amine compound represented by the following structural formula (12-1).

  The aforementioned hindered phenol compound may have the characteristics of a hindered amine compound. That is, the hindered phenol compound may further have an amino nitrogen atom and may have a bulky atomic group in the vicinity thereof.

  When both the first charge transport layer 14 and the second charge transport layer 15 contain an antioxidant and / or a light stabilizer, the ratio of the antioxidant and / or the light stabilizer in the second charge transport layer 15 W2 is preferably larger than the ratio W1 of the antioxidant and / or the light stabilizer in the first charge transport layer 14 (W2> W1). As described above, the second charge transport layer 15 exposed to an oxidizing gas such as ozone or NOx contains more antioxidants and / or light stabilizers, thereby efficiently oxidizing the second charge transport layer 15. Since the reactive gas can be captured and inactivated, the deterioration of the photoreceptor 1 due to the oxidizing gas can be effectively prevented. Moreover, since the total amount of the antioxidant and / or light stabilizer contained in the charge transport layer 16 as a whole can be suppressed, the photoreceptor 1 by containing the antioxidant and / or light stabilizer can be reduced. An adverse effect on electrical characteristics can be suppressed. Therefore, it is possible to improve the oxidation resistance gas property and further improve the electrical durability of the photoreceptor 1 without deteriorating electrical characteristics such as photoresponsiveness.

  When the first charge transport layer 14 contains an enamine compound represented by the general formula (1) and other charge transport materials, the second charge transport layer 15 is represented by the general formula (2). When the styryl compound and other charge transport materials are contained, the total weight of the charge transport material and binder resin containing the styryl compound represented by the general formula (2) in the second charge transport layer 15 The ratio W2 ′ of the total weight of the antioxidant and / or the light stabilizer with respect to the total weight of the charge transport material containing the enamine compound represented by the general formula (1) and the binder resin in the first charge transport layer 14 is oxidized. It is preferable that the ratio is greater than the ratio W1 ′ of the total weight of the inhibitor and / or the light stabilizer (W2 ′> W1 ′).

  In order to sufficiently suppress the deterioration of the photoreceptor 1 due to the oxidizing gas, the ratio W2 of the antioxidant and / or the light stabilizer in the second charge transport layer 15, that is, the styryl type represented by the general formula (2) The ratio [C2 / (A + B)] of the total weight (C2) of the antioxidant and / or the light stabilizer to the total weight (A + B) of the compound and the binder resin is preferably 0.01 or more and 0.1 or less. . If the ratio W2 is less than 0.01, the effects of improving the resistance to oxidation gas and improving the stability of the coating solution may not be sufficiently exhibited. If the ratio W2 exceeds 0.1, the electrical characteristics of the photoreceptor 1 may be adversely affected.

  The ratio of the antioxidant and / or the light stabilizer in the first charge transport layer 14, that is, the antioxidant with respect to the total weight (A ′ + B ′) of the enamine compound and binder resin represented by the general formula (1) and / or Alternatively, the ratio [C1 / (A ′ + B ′)] of the total weight (C1) of the light stabilizer is preferably 0.1 or less in order to more reliably suppress a decrease in electrical characteristics such as photoresponsiveness. More preferably, it is 0.04 or less. If the ratio W1 exceeds 0.1, the photoresponsiveness of the photoreceptor 1 may be reduced. The lower limit of the ratio W1 is not particularly limited, but is preferably 0.001 or more from the viewpoint of improving the oxidation resistance gas resistance of the photoreceptor 1 and the stability of the coating solution. If the ratio W1 is less than 0.001, the effects of improving the oxidation resistance gas resistance and the stability of the coating liquid may not be sufficiently exhibited.

  Further, in the first charge transport layer 14, the ratio (C1 / A ′) of the total weight (C1) of the antioxidant and / or the light stabilizer to the weight (A ′) of the enamine compound represented by the general formula (1). ) Is preferably 0.001 or more and 0.1 or less, and more preferably 0.001 or more and 0.05 or less. If the ratio C1 / A ′ is less than 0.001, there is a possibility that sufficient effects for improving the oxidation-resistant gas property and improving the stability of the coating solution may not be exhibited. If the ratio C1 / A ′ exceeds 0.1, the electrical characteristics of the photoreceptor 1 may be adversely affected.

  In the second charge transport layer 15, the ratio (C2 / A) of the total weight (C2) of the antioxidant and / or the light stabilizer to the weight (A) of the styryl compound represented by the general formula (2) Is preferably 0.001 or more and 1 or less, more preferably 0.05 or more and 0.5 or less. If the ratio C2 / A is less than 0.001, the effect of improving the oxidation resistance and stability of the coating solution may not be sufficiently obtained. If the ratio C2 / A exceeds 1, the electrical characteristics of the photoreceptor 1 may be adversely affected.

  In addition, each layer of the charge transport layer 16, that is, the first charge transport layer 14 and the second charge transport layer 15, is provided with a plasticizer or a surface modifier in order to improve film forming property, flexibility, or surface smoothness. Various additives such as may be added. Examples of plasticizers include dibasic acid esters such as biphenyl, biphenyl chloride, benzophenone, o-terphenyl, and phthalate esters, fatty acid esters, phosphate esters, various fluorohydrocarbons, chlorinated paraffins, and epoxy type plasticizers. Can be mentioned. Examples of the surface modifier include silicone oil and fluororesin. Further, fine particles of an inorganic compound or an organic compound may be added to each of the layers 14 and 15 of the charge transport layer 16 in order to increase mechanical strength and improve electrical characteristics.

  The layers 14 and 15 of the charge transport layer 16 can be formed by using the coating method used for forming the charge generation layer 12 described above. The coating liquid for the first charge transport layer for forming the first charge transport layer 14 is, for example, a solution or dispersion of a charge transport material containing an enamine compound represented by the general formula (1) and a binder resin in a suitable solvent. If necessary, it is prepared by adding various additives such as the above-mentioned antioxidants and light stabilizers. Similarly, the coating solution for the second charge transport layer for forming the second charge transport layer 15 is, for example, a charge transport material containing a styryl compound represented by the general formula (2) in an appropriate solvent and a binder resin. Is dissolved or dispersed, and various additives such as antioxidants and light stabilizers are added as necessary. As the solvent for these coating solutions, the same solvents as those used for the charge generating layer coating solution described above can be used. In addition, as a method for applying each coating solution, the same method as that for applying the charge generating layer coating solution onto the undercoat layer 12 described above can be used.

  The thickness d1 of the first charge transport layer 14 is preferably larger than the thickness d2 of the second charge transport layer 15 (d1> d2). If the thickness d1 of the first charge transport layer 14 is equal to or less than the thickness d2 of the second charge transport layer 15 (d1 ≦ d2), the photoresponsiveness of the photoreceptor 1 may not be sufficiently obtained. As described above, by making the thickness d1 of the first charge transport layer 14 larger than the thickness d2 of the second charge transport layer 15 (d1> d2), the photoreceptor 1 that is particularly excellent in photoresponsiveness is realized. Can do.

  The thickness d1 of the first charge transport layer 14 is preferably 5 μm or more and 40 μm or less, and more preferably 10 μm or more and 30 μm or less. If the thickness d1 of the first charge transport layer 14 is less than 5 μm, the photoresponsiveness of the entire charge transport layer 16 may not be sufficiently obtained. If the thickness d1 of the first charge transport layer 14 exceeds 40 μm, the thickness of the entire charge transport layer 16 becomes too large, and the resolution may be lowered.

  The thickness d2 of the second charge transport layer 15 is preferably 1 μm or more and 20 μm or less, more preferably 1 μm or more and 10 μm or less. When the thickness d2 of the second charge transport layer 15 is less than 1 μm, there is a possibility that the oxidation resistance gas property cannot be sufficiently ensured. Further, due to wear, all of the second charge transport layer 15 may disappear before the electrical life of the photoreceptor 1 and a sufficient life may not be obtained. If the thickness d2 of the second charge transport layer 15 exceeds 20 μm, the thickness of the entire charge transport layer 16 becomes too large, and the resolution may be lowered.

  The total thickness of the charge transport layer 16, that is, the sum (d1 + d2) of the thickness d1 of the first charge transport layer 14 and the thickness d2 of the second charge transport layer 15 is preferably 10 μm or more and 50 μm or less. More preferably, it is 20 μm or more and 40 μm or less. If the thickness of the entire charge transport layer 16 is less than 10 μm, the charge holding ability of the photoreceptor 1 may be lowered. If the total thickness of the charge transport layer 16 exceeds 50 μm, the resolution of the photoreceptor 1 may be reduced.

  As described above, in the photoreceptor 1 of the present embodiment, the charge transport layer 16 is composed of two layers of the first charge transport layer 14 and the second charge transport layer 15, but is not limited thereto. It may be composed of three or more layers. By comprising three or more layers in this way, it becomes easy to adjust electrical characteristics such as photoresponsiveness and sensitivity of the photoreceptor. However, the structure in which the charge transport layer 16 is formed of two layers as in the present embodiment is excellent in terms of productivity, manufacturing cost, and yield because there are fewer layers to be formed.

  When the charge transport layer 16 is composed of three or more layers, the second charge transport layer 15 containing the styryl compound represented by the general formula (2) is provided so as to face outward. Another charge transport layer may be further provided between the transport layer 15 and the first charge transport layer 14 or between the first charge transport layer 14 and the charge generation layer 13. The other charge transport layer preferably contains an enamine compound represented by the general formula (1). Thereby, it is possible to prevent a decrease in photoresponsiveness due to an increase in the number of layers constituting the charge transport layer 16. When the separate charge transport layer does not contain the enamine compound represented by the general formula (1), the separate charge transport layer is preferably provided between the first charge transport layer 14 and the second charge transport layer 15. . Accordingly, since the first charge transport layer 14 containing the enamine compound represented by the general formula (1) can be provided in contact with the charge generation layer 13, it is possible to suppress a decrease in photoresponsiveness of the photoreceptor. .

  FIG. 2 is an arrangement side view showing a simplified configuration of an image forming apparatus 100 according to another embodiment of the present invention. The image forming apparatus 100 according to the present embodiment includes the photoreceptor 1 according to the above-described embodiment. The image forming apparatus 100 includes the above-described photoreceptor 1 that is rotatably supported by an apparatus main body (not shown), and a drive unit (not shown) that rotates the photoreceptor 1 around the rotation axis 44 in the direction of an arrow 41. The drive means includes a motor as a power source, for example, and transmits the power from the motor to a support body constituting the core body of the photoconductor 1 via a gear (not shown), thereby rotating the photoconductor 1 at a predetermined peripheral speed. Let

  Around the photosensitive member 1, a charger 32 as a charging unit, an exposure unit 30, a developing unit 33 as a developing unit, a transfer unit 34 as a transferring unit, and a cleaner 36 as a cleaning unit are They are provided in this order from the upstream side to the downstream side in the rotation direction of the photosensitive member 1 indicated by reference numeral 41. The cleaner 36 is provided together with a static elimination lamp (not shown).

  The charger 32 charges the surface 43 of the photoreceptor 1 to a predetermined negative or positive potential by corona discharge or the like. The charger 32 is realized by non-contact charging means such as a corona discharge charger. The exposure unit 30 includes, for example, a semiconductor laser element as a light source, and exposes the surface 43 of the charged photoreceptor 1 by irradiating light 31 according to image information from the light source. The developing device 33 develops the electrostatic latent image formed on the surface 43 of the photoreceptor 1 by exposure by the exposure unit 30 with a developer to form a toner image which is a visible image. In the present embodiment, the developing device 33 is provided opposite to the photosensitive member 1 and supplies a developing roller 33 a that supplies toner to the surface 43 of the photosensitive member 1, and the developing roller 33 a rotates in parallel with the rotation axis 44 of the photosensitive member 1. A casing 33b is provided that supports the shaft so as to be rotatable about an axis and accommodates a developer containing toner in an internal space thereof.

  The transfer unit 34 sensitizes the toner image formed on the surface 43 of the photosensitive member 1 by applying, for example, a charge having a polarity opposite to that of the toner to the recording paper 51 that is a transfer material supplied to the photosensitive member 1. The recording sheet 51 is transferred from the surface 43 of the body 1. The transfer unit 34 is realized by a non-contact type transfer unit such as a corona discharge charger. The cleaner 36 cleans the surface 43 of the photoreceptor 1 after the toner image is transferred. In the present embodiment, the cleaner 36 is pressed against the surface 43 of the photoreceptor, and a cleaning blade 36a that peels off foreign matters such as toner and paper dust remaining on the surface 43 of the photoreceptor 1 after the transfer operation by the transfer device 34 from the surface 43. And a recovery casing 36b for storing foreign matter such as toner separated by the cleaning blade 36a.

  A fixing device 35 for fixing the transferred toner image to the recording paper 51 is provided in the direction in which the recording paper 51 to which the toner image has been transferred is conveyed. In the present embodiment, the fixing device 35 includes a heating roller 35a having a heating unit (not shown), and a pressure roller 35b that is provided to face the heating roller 35a and is pressed by the heating roller 35a to form a contact portion. .

  In the image forming apparatus 100, an image is formed as follows. First, in response to an instruction from a control unit (not shown), the photosensitive member 1 is rotationally driven in the direction of an arrow 41 by a driving unit, and the surface 43 is charged by a charger 32. Next, in response to an instruction from the control unit, light 31 is irradiated from the exposure unit 30 and the photosensitive member 1 is exposed. As a result, the surface charge of the portion irradiated with the light 31 is reduced, and a difference occurs between the surface potential of the portion irradiated with the light 31 and the surface potential of the portion not irradiated with the light 31. An electrostatic latent image is formed on the surface 43. Next, the electrostatic latent image is developed by the developing device 33, and a toner image is formed on the surface 43 of the photoreceptor 1.

  In synchronism with the exposure of the photosensitive member 1, the recording paper 51 is supplied to the transfer position between the transfer device 34 and the photosensitive member 1 from the direction of the arrow 42 by a conveying unit (not shown). When the recording paper 51 is supplied to the transfer position, the toner image formed on the surface 43 of the photoreceptor 1 is transferred to the recording paper 51 by the transfer device 34. Next, the recording paper 51 is heated and pressurized by the fixing device 35, and the toner image is fixed on the recording paper 51. The recording paper 51 on which the image is formed in this manner is discharged to the outside of the image forming apparatus 100 by the conveying unit.

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

  As described above, the photoreceptor 1 provided in the image forming apparatus 100 is excellent in electrical characteristics such as charging property, sensitivity, and photoresponsiveness, and is excellent in oxidation resistance gas property, and is generated from a charger 32 such as a corona discharge charger. It has the advantage of being less susceptible to degradation by oxidizing gases such as ozone and nitrogen oxides. For this reason, the photoreceptor 1 does not deteriorate the above-described good electrical characteristics even when used repeatedly, and has sufficient electrical characteristics for practical use even after repeated use. Therefore, the image forming apparatus 100 is excellent in durability and can stably form a high-quality image without image defects such as white spots and black belts over a long period of time.

  The image forming apparatus according to the present invention is not limited to the configuration of the image forming apparatus 100 shown in FIG. 2 described above, and any other apparatus can be used as long as it can use the photoconductor according to the present invention. Different configurations may be used.

  For example, in the image forming apparatus 100 of the present embodiment, the charger 32 is a non-contact charging unit, but is not limited thereto, and may be a contact charging unit such as a charging roller. . The transfer unit 34 is a non-contact type transfer unit that performs transfer without using a pressing force, but is not limited thereto, and is a contact type transfer unit that performs transfer using a pressing force. Also good. As the contact-type transfer means, for example, a transfer roller is provided, and the transfer roller is pressed against the photoconductor 1 from the surface opposite to the surface that contacts the surface 43 of the photoconductor 1 of the recording paper 51. In a state where the body 1 and the recording paper 51 are in pressure contact with each other, a toner image can be transferred to the recording paper 51 by applying a voltage to the transfer roller.

  Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples.

[Production example]
Production Example 1 Exemplified Compound No. Production of 1 (Production Example 1-1) Production of enamine intermediate To 100 mL of toluene, 23.3 g (1.0 equivalent) of N- (p-tolyl) -α-naphthylamine represented by the following structural formula (13) and Then, 20.6 g (1.05 equivalent) of diphenylacetaldehyde represented by the following structural formula (14) and 0.23 g (0.01 equivalent) of DL-10-camphorsulfonic acid were added and heated to produce by-products. While water was azeotroped with toluene and removed from the system, the reaction was allowed to stir for 6 hours. After completion of the reaction, the reaction solution was concentrated to about one-tenth (1/10) and gradually dropped into 100 mL of hexane, which was vigorously stirred, to form crystals. The produced crystal was separated by filtration and washed with cold ethanol to obtain 36.2 g of a pale yellow powdery compound.

The obtained compound was subjected to liquid chromatography-mass spectrometry (Liquid Chromatography-
As a result of analysis by Mass Spectrometry (abbreviation LC-MS), it corresponds to a molecular ion [M + H] ⁺ in which a proton is added to an enamine intermediate represented by the following structural formula (15) (calculated molecular weight: 411.20). Since a peak was observed at 412.5, it was confirmed that the obtained compound was an enamine intermediate represented by the following structural formula (15) (yield: 88%). LC-MS analysis results showed that the purity of the obtained enamine intermediate was 99.5%.

  As described above, N- (p-tolyl) -α-naphthylamine represented by Structural Formula (13) which is a secondary amine compound and diphenylacetaldehyde represented by Structural Formula (14) which is an aldehyde compound. By performing the dehydration condensation reaction, an enamine intermediate represented by the structural formula (15) could be obtained.

(Production Example 1-2) Production of enamine-aldehyde intermediate In 100 mL of anhydrous N, N-dimethylformamide (abbreviation DMF), 9.2 g (1.2 equivalents) of phosphorus oxychloride was gradually added under ice-cooling. Stir for about 30 minutes to prepare a Vilsmeier reagent. To this solution, 20.6 g (1.0 equivalent) of the enamine intermediate represented by the structural formula (15) obtained in (Production Example 1-1) was gradually added under ice cooling. Thereafter, the reaction solution was gradually heated to a temperature of 80 ° C., and stirred to react for 3 hours while maintaining the temperature at 80 ° C. After completion of the reaction, the reaction solution was allowed to cool and gradually added to 800 mL of a cooled 4N (4N) -sodium hydroxide aqueous solution to cause precipitation. The resulting precipitate was filtered off, sufficiently washed with water, and then recrystallized with a mixed solvent of ethanol and ethyl acetate to obtain 20.4 g of a yellow powdery compound.

As a result of analyzing the obtained compound by LC-MS, it was found that an enamine-aldehyde intermediate (calculated molecular weight: 439.19) represented by the following structural formula (16) was added to a molecular ion [M + H] ⁺ added with a proton. Since the corresponding peak was observed at 440.5, it was confirmed that the obtained compound was an enamine-aldehyde intermediate represented by the following structural formula (16) (yield: 93%). LC-MS analysis results showed that the resulting enamine-aldehyde intermediate had a purity of 99.7%.

  As described above, the enamine-aldehyde intermediate represented by the structural formula (16) was obtained by formylating the enamine intermediate represented by the structural formula (15) by the Vilsmeier reaction.

(Production Example 1-3) Exemplified Compound No. 1 8.8 g (1.0 equivalent) of the enamine-aldehyde intermediate represented by the structural formula (16) obtained in Production Example 1-2 and diethyl represented by the following structural formula (17) Cinnamyl phosphonate (6.1 g, 1.2 equivalent) was dissolved in anhydrous DMF (80 mL), and potassium t-butoxide (2.8 g, 1.25 equivalent) was gradually added to the solution at room temperature.

  Thereafter, the reaction solution was heated to a temperature of 50 ° C. and stirred for 5 hours while being heated to keep the temperature at 50 ° C. The reaction solution was allowed to cool and then poured into excess methanol. The precipitate was collected and dissolved in toluene to obtain a toluene solution. The toluene solution was transferred to a separatory funnel and washed with water. Then, the organic layer was taken out, and the taken out organic layer was dried over magnesium sulfate. After drying, the organic layer from which the solid was removed was concentrated and subjected to silica gel column chromatography to obtain 10.1 g of yellow crystals.

As a result of analyzing the obtained crystals by LC-MS, Exemplified Compound No. 1 shown in Table 1 as the target compound was obtained. A peak corresponding to molecular ion [M + H] ⁺ in which a proton was added to the enamine compound 1 (calculated molecular weight: 539.26) was observed at 540.5. In addition, nuclear magnetic resonance (Nuclear Magnetic) in deuterated chloroform (chemical formula: CDCl ₃ ) of the obtained crystal.
Resonance (abbreviation: NMR) spectrum was measured, and as a result, Exemplified Compound No. A spectrum supporting the structure of one enamine compound was obtained. From the analysis results of LC-MS and the measurement results of NMR spectrum, the obtained crystals were identified as Exemplified Compound No. 1 (yield: 94%). In addition, from the results of LC-MS analysis, the obtained Exemplified Compound Nos. The purity of 1 enamine compound was found to be 99.8%.

  As described above, by performing the Wittig-Horner reaction between the enamine-aldehyde intermediate represented by the structural formula (16) and the diethylcinnamylphosphonate represented by the structural formula (17) which is a Wittig reagent, Example Compound No. 1 shown in FIG. One enamine compound could be obtained.

(Production Example 2) Exemplified Compound No. Production of 61 In place of 23.3 g (1.0 equivalent) of N- (p-tolyl) -α-naphthylamine represented by the structural formula (13), N- (p-methoxyphenyl) -α-naphthylamine Production of enamine intermediate by dehydration condensation reaction (yield: 94%) and production of enamine-aldehyde intermediate by Vilsmeier reaction in the same manner as in Production Example 1 except that 4.9 g (1.0 equivalent) is used. (Yield: 85%) was performed, and the Wittig-Horner reaction was further performed to obtain 7.9 g of a yellow powdery compound. The amount of reagent used for each reaction was changed so that the equivalent relationship between the reagent and the substrate was the same as the equivalent relationship between the reagent and the substrate used in Production Example 1.

As a result of analyzing the obtained compound by LC-MS, Exemplified Compound Nos. A peak corresponding to a molecular ion [M + H] ^{+ obtained} by adding a proton to 61 enamine compound (calculated molecular weight: 555.26) was observed at 556.7. The measured NMR spectra during CDCl ₃ of the obtained compound, Exemplary Compound No. A spectrum supporting the structure of 61 enamine compounds was obtained. From the analysis results of LC-MS and the measurement results of NMR spectrum, the obtained compound was exemplified by Compound No. 1. 61 enamine compounds were confirmed (yield: 92%). In addition, from the results of LC-MS analysis, the obtained Exemplified Compound Nos. The purity of 61 enamine compounds was found to be 99.0%.

  As described above, by carrying out the three-stage reaction of the dehydration condensation reaction, the Vilsmeier reaction and the Wittig-Horner reaction, the exemplary compound Nos. 61 enamine compounds could be obtained.

Production Example 3 Exemplified Compound No. Preparation of No. 46 2.0 g (1.0 equivalent) of the enamine-aldehyde intermediate represented by the structural formula (16) obtained in Production Example 1-2 and Wittig represented by the following structural formula (18) 1.53 g (1.2 equivalents) of the reagent was dissolved in 15 mL of anhydrous DMF, and 0.71 g (1.25 equivalents) of potassium t-butoxide was gradually added to the solution at room temperature.

  Thereafter, the reaction solution was heated to a temperature of 50 ° C. and stirred for 5 hours while being heated to keep the temperature at 50 ° C. The reaction solution was allowed to cool and then poured into excess methanol. The precipitate was collected and dissolved in toluene to obtain a toluene solution. The toluene solution was transferred to a separatory funnel and washed with water. Then, the organic layer was taken out, and the taken out organic layer was dried over magnesium sulfate. After drying, the organic layer from which the solid was removed was concentrated and subjected to silica gel column chromatography to obtain 2.37 g of yellow crystals.

As a result of analyzing the obtained crystal by LC-MS, Exemplified Compound Nos. A peak corresponding to molecular ion [M + H] ⁺ in which proton was added to 46 enamine compounds (calculated molecular weight: 565.28) was observed at 566.4. The measured NMR spectra during CDCl ₃ of the obtained compound, Exemplary Compound No. A spectrum supporting the structure of 46 enamine compounds was obtained. From the analysis results of LC-MS and the measurement results of NMR spectrum, the obtained compound was exemplified by Compound No. 1. It was confirmed that it was 46 enamine compounds (yield: 92%). In addition, from the results of LC-MS analysis, the obtained Exemplified Compound Nos. The purity of 46 enamine compounds was found to be 99.8%.

  As described above, by carrying out the Wittig-Horner reaction between the enamine-aldehyde intermediate represented by the structural formula (16) and the Wittig reagent represented by the structural formula (18), the exemplified compound Nos. 46 enamine compounds could be obtained.

[Example]
Example 1
Titanium oxide TTO-MI-1 (trade name, dendritic rutile type surface-treated with Al ₂ O ₃ and ZrO ₂ , titanium component 85%, manufactured by Ishihara Sangyo Co., Ltd.) and alcohol-soluble nylon resin CM8000 ( (Trade name, manufactured by Toray Industries, Inc.) 3 parts by weight is added to a mixed solvent of 60 parts by weight of methanol and 40 parts by weight of 1,3-dioxolane, and is subjected to a dispersion treatment with a paint shaker for 10 hours. A liquid was prepared. The coating solution was filled in the coating tank, the conductive support was dipped and then pulled up, and naturally dried to form a subbing layer having a thickness of 0.9 μm. As the conductive support, an aluminum cylindrical conductive support having an outer diameter of 30 mm and a length in the longitudinal direction of 346 mm was used.

Then, 10 parts by weight of butyral resin S-LEC BL-2 (trade name, manufactured by Sekisui Chemical Co., Ltd.), 1400 parts by weight of 1,3-dioxolane, and titanyl phthalocyanine (in the above general formula (4), R ²¹ , R ²² , R ²³ and R ²⁴ are all hydrogen atoms) 15 parts by weight were dispersed in a ball mill for 72 hours to prepare a charge generation layer coating solution. This coating solution was applied onto the previously formed undercoat layer by a dip coating method as in the case of the undercoat layer, and naturally dried to form a charge generation layer having a thickness of 0.2 μm.

Subsequently, the exemplified compound No. 1 shown in Table 9 above as a charge transporting substance. 61 parts by weight of enamine compound 61, 55 parts by weight of polycarbonate resin GK-700 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) and 45 parts by weight of polycarbonate resin GH-503 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) as the binder resin Then, 2 parts by weight of Sumilizer BHT (trade name, manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant was mixed and dissolved in 708 parts by weight of tetrahydrofuran to prepare a first charge transport layer coating solution. The obtained coating solution was applied onto the previously formed charge generation layer by a dip coating method as in the case of the undercoat layer, and then naturally dried to form a first charge transport layer having a thickness of 20 μm. In addition, the Sumilizer BHT is a hindered phenol compound in which R ¹⁴ is a methyl group in the above general formula (11), that is, 2,6-di (t-butyl) -4-methylphenol.

  Next, 100 parts by weight of a styryl compound represented by the above structural formula (2-14) as a charge transport material, 110 parts by weight of a polycarbonate resin GK-700 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) as a binder resin, and polycarbonate 90 parts by weight of resin GH-503 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) and 10 parts by weight of Sumilizer BHT (manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant are mixed and dissolved in 980 parts by weight of tetrahydrofuran. A coating solution for two charge transport layers was prepared. The obtained coating solution was applied on the first charge transport layer formed previously by dip coating as in the case of the undercoat layer, and dried at a temperature of 130 ° C. for 1 hour to give a second charge having a thickness of 5 μm. A transport layer was formed, and a charge transport layer having a total thickness of 25 μm was formed. In this way, the photoreceptor of Example 1 was produced.

(Example 2)
In forming the first charge transport layer, Exemplified Compound Nos. In place of the enamine compound 61, Exemplified Compound Nos. A photoconductor of Example 2 was produced in the same manner as Example 1 except that 46 enamine compound was used.

(Example 3)
In the formation of the first charge transport layer, the photosensitivity of Example 3 was obtained in the same manner as in Example 1 except that the amount of use of Sumilizer BHT (manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant was changed to 10 parts by weight. The body was made.

Example 4
In the formation of the second charge transport layer, the photosensitivity of Example 4 was obtained in the same manner as in Example 1, except that the amount used of the antioxidant BHT (manufactured by Sumitomo Chemical Co., Ltd.) was changed to 1 part by weight. The body was made.

(Example 5)
In the same manner as in Example 1, an undercoat layer, a charge generation layer, and a first charge transport layer were formed. Next, 100 parts by weight of a styryl compound represented by the above structural formula (2-14) as a charge transport material, 77 parts by weight of polycarbonate resin GK-700 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) as a binder resin, and polycarbonate 63 parts by weight of resin GH-503 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) and 8 parts by weight of Sumilizer BHT (trade name, manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant are mixed and dissolved in 980 parts by weight of tetrahydrofuran. Thus, a coating solution for the second charge transport layer was prepared. Using the obtained coating solution, a second charge transport layer was formed in the same manner as in Example 1, and a photoconductor of Example 5 was produced.

(Example 6)
In the same manner as in Example 1, an undercoat layer, a charge generation layer, and a first charge transport layer were formed. Next, 100 parts by weight of a styryl compound represented by the above structural formula (2-14) as a charge transport material, 330 parts by weight of polycarbonate resin GK-700 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) as a binder resin, and polycarbonate 270 parts by weight of resin GH-503 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) and 23 parts by weight of Sumilizer BHT (trade name, manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant are mixed and dissolved in 1200 parts by weight of tetrahydrofuran. Thus, a coating solution for the second charge transport layer was prepared. Using the obtained coating solution, a second charge transport layer was formed in the same manner as in Example 1, and a photoreceptor of Example 6 was produced.

(Example 7)
In the same manner as in Example 1, an undercoat layer, a charge generation layer, and a first charge transport layer were formed. Next, 100 parts by weight of a styryl compound represented by the above structural formula (2-14) as a charge transport material, 385 parts by weight of polycarbonate resin GK-700 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) as a binder resin, and polycarbonate 315 parts by weight of resin GH-503 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) and 27 parts by weight of Sumilizer BHT (trade name, manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant are mixed and dissolved in 1200 parts by weight of tetrahydrofuran. Thus, a coating solution for the second charge transport layer was prepared. Using the obtained coating solution, a second charge transport layer was formed in the same manner as in Example 1, and a photoconductor of Example 7 was produced.

(Comparative Example 1)
In the same manner as in Example 1, an undercoat layer and a charge generation layer were formed. Next, 100 parts by weight of a styryl compound represented by the above structural formula (2-14) as a charge transport material, and 71.5 parts by weight of a polycarbonate resin GK-700 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) as a binder resin. And 58.5 parts by weight of polycarbonate resin GH-503 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) and 2.3 parts by weight of Sumilizer BHT (trade name, manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant, A charge transport layer coating solution was prepared by dissolving in 892 parts by weight of tetrahydrofuran. The obtained coating solution was applied on the previously formed charge generation layer by the dip coating method as in the case of the undercoat layer of Example 1, and dried at a temperature of 130 ° C. for 1 hour to obtain a charge of 25 μm thickness. Only one transport layer was formed. In this manner, a photoreceptor of Comparative Example 1 having a charge transport layer formed in a single layer was produced.

(Comparative Example 2)
In forming the first charge transport layer, Exemplified Compound Nos. A photoconductor of Comparative Example 2 was produced in the same manner as in Example 1, except that a butadiene-based compound represented by the following structural formula (19) was used instead of 61 enamine compound.

(Comparative Example 3)
In the same manner as in Example 1, an undercoat layer and a charge generation layer were formed. Subsequently, the exemplified compound No. 1 shown in Table 9 above as a charge transporting substance. 61 parts by weight of enamine compound 61, 72 parts by weight of polycarbonate resin GK-700 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) and 59 parts by weight of polycarbonate resin GH-503 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) Then, 2.3 parts by weight of Sumilizer BHT (trade name, manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant was mixed and dissolved in 892 parts by weight of tetrahydrofuran to prepare a coating solution for a charge transport layer. The obtained coating solution was applied on the previously formed charge generation layer by the dip coating method as in the case of the undercoat layer of Example 1, and dried at a temperature of 130 ° C. for 1 hour to obtain a charge of 25 μm thickness. Only one transport layer was formed. In this way, a photoreceptor of Comparative Example 3 having a charge transport layer formed in a single layer was produced.

(Comparative Example 4)
In the same manner as in Example 1, an undercoat layer and a charge generation layer were formed. Subsequently, the exemplified compound No. 1 shown in Table 9 above as a charge transporting substance. 61 parts by weight of enamine compound 61 and 20 parts by weight of a styryl compound represented by the structural formula (2-14), 72 parts by weight of polycarbonate resin GK-700 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) as a binder resin and polycarbonate 59 parts by weight of resin GH-503 (trade name, manufactured by Idemitsu Kosan Co., Ltd.) and 2.3 parts by weight of Sumilizer BHT (trade name, manufactured by Sumitomo Chemical Co., Ltd.) as an antioxidant are mixed to obtain 892 parts by weight of tetrahydrofuran. To obtain a coating solution for charge transport layer. The obtained coating solution was applied on the previously formed charge generation layer by the dip coating method as in the case of the undercoat layer of Example 1, and dried at a temperature of 130 ° C. for 1 hour to obtain a charge of 25 μm thickness. Only one transport layer was formed. In this way, a photoreceptor of Comparative Example 4 having a charge transport layer formed in a single layer was produced.

(Comparative Example 5)
In the formation of the second charge transport layer, the same procedure as in Example 1 was conducted except that a styryl compound represented by the following structural formula (20) was used instead of the styryl compound represented by the structural formula (2-14). Thus, a photoreceptor of Comparative Example 5 was produced.

(Comparative Example 6)
In the formation of the second charge transport layer, the same procedure as in Example 1 was conducted except that the butadiene compound represented by the structural formula (19) was used instead of the styryl compound represented by the structural formula (2-14). Thus, a photoreceptor of Comparative Example 6 was produced.

[Evaluation]
The characteristics of the photoreceptors of Examples 1 to 7 and Comparative Examples 1 to 6 produced as described above were evaluated as follows.

(Evaluation 1)
Each of the photoconductors of Examples 1 to 7 and Comparative Examples 1 and 2 is mounted on a test image forming apparatus, and a low temperature / low humidity (L / L) environment with a temperature of 5 ° C. and a relative humidity of 20%. High temperature / humidity (H / H: High Temperature / High)
Humidity) In each environment, the light response was evaluated as follows. The test image forming apparatus uses a commercially available laser printer (trade name: AR-450, manufactured by Sharp Corporation) equipped with a corona discharge charger as charging means for the photoconductor, and measures the surface potential of the photoconductor during the image forming process. What provided the surface electrometer (brand name: CATE751, the Gentec company make) so that it could do was used. The above-mentioned laser printer AR-450 is a negatively charged image forming apparatus that performs an electrophotographic process by negatively charging the surface of the photoreceptor.

  Using the test image forming apparatus on which the photoreceptors of Examples 1 to 7 and Comparative Examples 1 and 2 are mounted, the surface of the photoreceptor is charged to minus (−) 500 V by a charger and then exposed to laser light. The surface potential of the photoconductor immediately after the exposure was measured, and the absolute value thereof was determined as the exposure potential VL [V]. It was evaluated that the smaller the exposure potential VL, the better the photoresponsiveness.

  The evaluation results are shown in Table 33. In the column of the BHT ratio in Table 33, the ratio of the weight of the stabilizer BHT that is an antioxidant to the total weight of the charge transport material and the binder resin in the first charge transport layer or the second charge transport layer is described. The B ′ / A ′ column describes the ratio of the weight of the binder resin to the weight of the charge transport material in the first charge transport layer, and the B / A column describes the charge transport in the second charge transport layer. The ratio of the weight of the binder resin to the weight of the substance is described. These are also described in Table 34 described later. For Comparative Example 1 in which the charge transport layer is formed in a single layer, the type of the charge transport material used, the BHT ratio in the charge transport layer, and the weight of the charge transport material in the column of the first charge transport layer. The weight ratio is described, and “-” is described in the column of the second charge transport layer.

  As shown in Table 33, from comparison between Examples 1 to 7 and Comparative Example 1, the charge transport layer contained the first charge transport layer containing the enamine compound represented by the general formula (1) and the general formula (2). In the photoreceptors of Examples 1 to 7 formed of two layers including a second charge transport layer containing a styryl compound represented by formula (1), the charge transport layer is represented by the general formula (2). It was found that the exposure potential VL was small and the photoresponsiveness was excellent in both the H / H environment and the L / L environment, as compared with the photoconductor of Comparative Example 1 formed only by the layer containing selenium.

  From comparison between Examples 1 to 7 and Comparative Example 2, the photoreceptors of Examples 1 to 7 using the enamine compound represented by the general formula (1) as the charge transport material of the first charge transport layer are represented by the general formula: It was found that the exposure potential VL was small and the photoresponsiveness was excellent compared to the photoreceptor of Comparative Example 2 using a charge transport material other than the enamine compound represented by (1).

  From a comparison between Examples 1, 2, 5-7 and Example 3, as in Examples 1, 2, 5-7, the ratio W2 of BHT, which is an antioxidant in the second charge transport layer, is set to the first charge. It has been found that the exposure potential VL can be reduced and the photoresponsiveness can be improved by making it larger than the BHT ratio W1 in the transport layer.

  From comparison between Examples 1 to 6 and Example 7, as in Examples 1 to 6, the binder resin with respect to the weight (A) of the styryl compound represented by the general formula (2) in the second charge transport layer was determined. It was found that by setting the weight (B) ratio (B / A) to 6.0 or less, the exposure potential VL can be reduced and the photoresponsiveness can be further improved.

  Further, from a comparison between Example 1 and Example 2, the photoreceptor of Example 1 using an enamine compound in which m is 1 in the above general formula (1b) as the charge transport material of the first charge transport layer is as follows. It can be seen that the exposure potential VL is small and the photoresponsiveness is excellent as compared with the photoreceptor of Example 2 using the enamine compound in which m is 2 in the general formula (1b). Therefore, as in Example 1, by using the enamine compound in which m is 1 in the general formula (1b) as the charge transport material of the first charge transport layer, the exposure potential VL is further reduced and the photoresponsiveness is increased. It was found that a particularly excellent photoreceptor can be obtained.

(Evaluation 2)
The photoreceptors of Examples 1 to 7 and Comparative Examples 3 to 6 were evaluated for (a) oxidation resistance gas resistance and (b) printing durability as follows.

(A) Oxidation-resistant gas resistance Each of the photoreceptors of Examples 1 to 7 and Comparative Examples 3 to 6 is a commercially available full-color copier (trade name: ARC-150, equipped with a corona discharge charger as charging means for the photoreceptor. The test images having a predetermined pattern were continuously copied on 5000 sheets of recording paper in a low temperature / low humidity (L / L) environment having a temperature of 5 ° C. and a relative humidity of 20%. Thereafter, the copier was turned off and allowed to stand overnight (about 20 hours), and then a halftone image was copied onto a recording sheet, which was used as an evaluation image. Here, the halftone image is an image in which gradation of the image is expressed by gradation using black and white dots.

The formed evaluation image was visually observed to determine whether or not each dot was blurred, that is, whether or not image blur occurred. Further, white spots and black belts are formed on a portion of the recording paper corresponding to a portion where the toner image is transferred from a portion of the photosensitive member that is disposed in the vicinity of the corona discharge charger while the power of the copying machine is turned off. It was determined whether or not this occurred. Based on these determination results, the oxidation resistance gas resistance of the photoconductor was evaluated by the degree of occurrence of image defects such as image blurring, white spots and black belts. The evaluation criteria for the oxidation-resistant gas resistance are as follows.
A: Excellent. No image defects have occurred.
○: Good. Although some image defects have occurred, it is negligible.
Δ: Yes. Although some image defects have occurred, there is no problem in practical use.
×: Impossible. Many image defects occur and cannot be used.

(B) Printing durability Each of the photoconductors of Examples 1 to 7 and Comparative Examples 3 to 6 is mounted on a test image forming apparatus, and is at room temperature / normal humidity (N / N: 25 ° C., relative humidity 50%). Normal Temperature / Normal
In a Humidity environment, a printing durability test was performed in which a letter test chart manufactured by Sharp Corporation was continuously formed on 100,000 sheets of recording paper. As the test image forming apparatus, a commercially available laser printer (trade name: AR-450, manufactured by Sharp Corporation) is used, and the pressure at which the cleaning blade of the cleaning device comes into contact with the photosensitive member, that is, the so-called cleaning blade pressure is 21 as the initial linear pressure. The one adjusted to 4 g / cm was used.

  The thickness of the photosensitive layer before and after the printing durability test was measured using an instantaneous multi-photometry system MCPD-1100 (trade name, manufactured by Otsuka Electronics Co., Ltd.) based on the optical interference method. From the difference from the thickness of the photosensitive layer after the printing test, the amount of film reduction of the photosensitive layer per 100,000 revolutions was determined. The smaller the film loss, the better the printing durability.

  The above evaluation results are shown in Table 34. In Table 34, for Comparative Examples 3 and 4 in which the charge transport layer is formed as a single layer, the charge transport material used, the BHT ratio in the charge transport layer, and the weight of the charge transport material are listed in the first charge transport layer column. The ratio of the weight of the binder resin with respect to is described, and "-" is described in the column of the second charge transport layer.

  From comparison between Examples 1 to 7 and Comparative Example 3, as in Examples 1 to 7, the first charge transport layer containing the enamine compound represented by the general formula (1) is further represented by the general formula (2). A photoreceptor in which a charge transport layer is formed by a single layer containing an enamine compound represented by the general formula (1) as in Comparative Example 3 by laminating a second charge transport layer having a styryl compound represented It was found that the oxidation-resistant gas resistance can be improved as compared with the above, and a high-quality image free from image defects can be formed over a long period.

  From comparison between Examples 1 to 7 and Comparative Example 4, the charge transport layer is composed of two layers as in Examples 1 to 7, and the charge transport material is formed on the second charge transport layer facing outward from the two layers. As shown in Comparative Example 4, the photoconductor containing the styryl compound represented by the general formula (2) has a single charge transport layer, and the charge transport layer is represented by the general formula (1). As compared with the photoreceptor containing the enamine compound and the styryl compound represented by the general formula (2), it has been found that the oxidation resistance is superior.

  From the comparison between Examples 1 to 7 and Comparative Examples 5 and 6, as in Examples 1 to 7, photosensitivity using the styryl compound represented by the general formula (2) as the charge transport material of the first charge transport layer. As shown in Comparative Examples 5 and 6, the body is superior in resistance to oxidation gas compared to a photoreceptor using other charge transport materials, and even when used repeatedly over a long period of time, a high-quality image without image defects is obtained. It turned out that it can provide.

  Further, from the comparison between Examples 1, 2, 5-7 and Example 4, the ratio W2 of the antioxidant in the second charge transport layer is set to the first charge transport layer as in Examples 1, 2, 5-7. It has been found that by making the ratio larger than the ratio W1 of the antioxidant, the oxidation resistance gas resistance is improved and the stability of the image quality over a long period of time is improved.

  From a comparison between Examples 1 to 4, 6, and 7 and Example 5, the weight of the styryl compound represented by the general formula (2) in the second charge transport layer as in Examples 1 to 4, 6, and 7 is shown. It was found that when the ratio (B / A) of the weight (B) of the binder resin to (A) is 2.0 or more, the printing durability can be improved and excellent mechanical durability can be realized. From this result and the result shown in Table 33, the optical response was obtained by setting the ratio B / A in the second charge transport layer to 2.0 or more and 6.0 or less as in Examples 1 to 4 and 6. It was found that a photoconductor excellent in both properties and mechanical durability can be obtained.

1 is a partial cross-sectional view showing a simplified configuration of an electrophotographic photosensitive member 1 according to an embodiment of the present invention. FIG. 10 is a side view of a layout showing a simplified configuration of an image forming apparatus 100 according to another embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 11 Conductive support body 12 Undercoat layer 13 Charge generation layer 14 1st charge transport layer 15 2nd charge transport layer 16 Charge transport layer 17 Photosensitive layer 30 Exposure means 32 Charger 33 Developer 34 Transfer device 35 Fixing device 36 Cleaner 100 Image forming apparatus

Claims (7)

An electrophotographic photosensitive member in which a charge generation layer, a first charge transport layer and a second charge transport layer are sequentially laminated on a conductive support,
The first charge transport layer contains an enamine compound represented by the following general formula (1),
The second charge transport layer contains an styryl compound represented by the following general formula (2).

[Wherein, Ar ¹ and Ar ² each represents an aryl group or a heterocyclic group which may have a substituent. Ar ³ represents an aryl group, heterocyclic group, aralkyl group or alkyl group which may have a substituent. R is a divalent aromatic ring group or heterocyclic group, or group = CAr ⁴ Ar ⁵ (Ar ⁴ and Ar ⁵ each may have a hydrogen atom or a substituent, aryl group, heterocyclic group, aralkyl group Or an alkyl group, provided that Ar ⁴ and Ar ⁵ are not hydrogen atoms at the same time. R ¹ represents a hydrogen atom, a halogen atom or an alkyl group which may have a substituent. R ² , R ³ and R ⁴ each represent a hydrogen atom or an optionally substituted alkyl group, aryl group, heterocyclic group or aralkyl group. n represents an integer of 0 to 3. When there are a plurality of R ² and R ³ groups, the plurality of R ² groups may be the same or different, and the plurality of R ³ groups may be the same or different. R ⁵ represents a hydrogen atom, a halogen atom or an optionally substituted alkyl group, alkoxy group, dialkylamino group or aryl group. l shows the integer of 1-6. When R ⁵ is in plurality, a plurality of R ⁵ may be different well or be the same, or may form a divalent condensed cyclic group with a naphthylene group which they are attached. ]

[In the formula, Ar ⁶ represents an aryl group which may have a substituent. Ar ⁷ represents a hydrogen atom or an alkyl group or an aryl group which may have a substituent. Ar ⁸ represents a phenylene group, a naphthylene group, a biphenylene group or an anthrylene group which may have a substituent. R ⁶ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Ar ⁹ is an aryl group which may have a substituent or the general formula (3)

(In the formula, R ⁷ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms). ] The electrophotographic photoreceptor according to claim 1, wherein the enamine compound represented by the general formula (1) is an enamine compound represented by the following general formula (1a).

[Wherein, Ar ⁴ , Ar ⁵ , R ⁵ and l have the same definitions as in general formula (1). m represents 1 or 2. R ⁸ , R ⁹ and R ¹⁰ each represent a hydrogen atom, a halogen atom or an optionally substituted alkyl group, alkoxy group, dialkylamino group or aryl group. i, j, and k each represent an integer of 1 to 5. When R ^{8, R 9} or ^{R 10} is a plurality, a plurality of ^R 8, ^{R 9} or ^{R 10} may be different well or even each same or monovalent condensed ring together with the phenyl group to which they are bonded A group may be formed. ] The electrophotographic photosensitive member according to claim 2, wherein the enamine compound represented by the general formula (1a) is an enamine compound represented by the following general formula (1b).

[Wherein, m is as defined in the general formula (1a). R ^10a represents an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. ] In the general formula (2), the styryl compound represented by the general formula (2)
Ar ⁶ is a phenyl group which may have an alkyl group having 1 to 4 carbon atoms as a substituent,
Ar ⁷ is a hydrogen atom,
Ar ⁸ is a phenylene group,
R ⁶ is a hydrogen atom,
The electrophotographic photosensitive member according to any one of claims 1 to 3, wherein Ar ⁹ is a styryl compound having a phenyl group. The second charge transport layer further contains a binder resin;
The ratio (B / A) of the weight (B) of the binder resin to the weight (A) of the styryl compound in the second charge transport layer is 2.0 or more and 6.0 or less. The electrophotographic photosensitive member according to any one of -4. The first charge transport layer and the second charge transport layer further contain a binder resin and at least one of an antioxidant and a light stabilizer,
The ratio W2 of the total weight of the antioxidant and / or light stabilizer to the total weight of the styryl compound and binder resin in the second charge transport layer is based on the total weight of the enamine compound and binder resin in the first charge transport layer. 6. The electrophotographic photoreceptor according to claim 1, wherein the total weight ratio W1 of the antioxidant and / or the light stabilizer is larger (W2> W1). The electrophotographic photosensitive member according to any one of claims 1 to 6,
Charging means for charging the electrophotographic photosensitive member;
Exposure means for exposing a charged electrophotographic photosensitive member;
An image forming apparatus comprising: developing means for developing an electrostatic latent image formed by exposure.

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