JP2008275779A - Electrophotographic photoreceptor and image forming apparatus including the same, and triarylamine dimer compound and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that is superior in electrical properties such as sensitivity and photoresponsiveness, environmental stability and mechanical durability, and an image forming apparatus including the same, and a triarylamine dimer compound, and to provide a method for producing the same. <P>SOLUTION: The electrophotographic photoreceptor is obtained, by stacking a single-layer type photosensitive layer containing a charge generating material and a charge transport material or a layer stacked type photosensitive layer, formed by stacking a charge generating layer containing a charge-generating material and a charge transport layer, containing a charge transport material on a conductive support, comprising a conductive material, where the single-layer type photosensitive layer or the charge transport layer of the layer stack type photosensitive layer contains a triarylamine dimer compound, having a specific substituent pattern as the charge transport material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photosensitive member containing a triarylamine dimer compound as an organic photoconductive material, an image forming apparatus including the same, a triarylamine dimer compound, and a method for producing the same.

In recent years, organic photoconductive materials have been extensively researched and developed and used not only for electrophotographic photoreceptors (hereinafter also simply referred to as “photoreceptors”), but also for electrostatic recording elements, sensor materials, or organic electroluminescent (Electro). Luminescent (abbreviation: EL) devices have begun to be applied.
In addition, photoreceptors using organic photoconductive materials are not limited to the field of copying machines, but are also used in fields such as printing plate materials, slide films, and microfilms that previously used silver salt photography technology. Yes. For example, it is also applied to a high-speed printer using a laser, a light emitting diode (abbreviated as LED), a cathode ray tube (abbreviated as CRT), or the like as a light source. With the expansion of the application range of electrophotographic technology, the demand for photoreceptors is becoming advanced and wide.

Conventionally, inorganic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive material such as selenium, zinc oxide or cadmium sulfide have been widely used as the photoreceptor.
Inorganic photoconductors have some basic characteristics as photoconductors, but have disadvantages such as difficulty in forming a photosensitive layer, poor plasticity, and high production costs. In addition, inorganic photoconductive materials are generally highly toxic and have significant limitations in manufacturing and handling.
As described above, since the inorganic photoconductive material and the inorganic photoreceptor using the inorganic photoconductive material have many drawbacks, research and development of the organic photoconductive material has been advanced.

Organic photoconductors using organic photoconductive materials have good film-forming properties, excellent flexibility, light weight, good transparency, and a wide wavelength range by appropriate sensitization methods. However, it has been gradually developed as the main force of the photoconductor because it has an advantage that a photoconductor showing good sensitivity can be easily designed.
Organic photoreceptors initially had drawbacks in sensitivity and durability, but these drawbacks were the development of function-separated photoreceptors in which the charge generation function and charge transport function were shared by different substances. Is significantly improved. In addition to the above-mentioned advantages of the organic photoconductor, this function-separated type photoconductor also has the advantage that a wide range of materials can be selected for the photosensitive layer and a photoconductor having arbitrary characteristics can be produced relatively easily. Have.

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

The charge generating materials used in these functionally separated photoreceptors include various materials such as phthalocyanine pigments, squarylium dyes, azo pigments, perylene pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes, and pyrylium salt dyes. Various materials that have been studied and have high light resistance and high charge generation ability have been proposed.
Examples of the charge transporting substance include pyrazoline compounds (for example, see (Patent Document 1)), hydrazone compounds (for example, Japanese Patent Laid-Open No. 54-150128 (Patent Document 2), Japanese Patent Publication No. 55-42380 (Patent Document). 3) and JP-A-55-52063 (Patent Document 4)), triphenylamine compounds (for example, JP-B-58-32372 (Patent Document 5) and JP-A-54-151955 (Patent Document) 6)) Various compounds such as stilbene compounds (for example, see Japanese Patent Application Laid-Open No. 58-198043 (Patent Document 7) and Japanese Patent Application Laid-Open No. 2-190862 (Patent Document 8)) are known.

The charge transport material is required to have the following basic characteristics.
(1) Stable to light and heat (2) Stable to ozone, nitrogen oxide (NO _x ), nitric acid, etc. generated by corona discharge when charging the surface of the photoreceptor.
(3) having a high charge transport capability;
(4) High compatibility with organic solvents and binders,
(5) Production is easy and inexpensive However, although the charge transport materials described in the above-mentioned prior art satisfy some of them, they do not satisfy all at a high level.

Among the above properties, it is particularly required to have a high charge transport capability.
For example, when the charge transport layer formed by dispersing the charge transport material together with the binder resin is the surface layer of the photoreceptor, the charge transport material has a high charge transport capability in order to ensure sufficient photoresponsiveness. Is required. In addition, when the photoconductor is mounted and used in a copying machine or a laser beam printer, a part of the surface layer of the photoconductor is forced to be scraped off by a contact member such as a cleaning blade or a charging roller. The In order to enhance the durability of copying machines and laser beam printers, a surface layer that is strong against the contact members, that is, a surface layer with high printing durability that is hardly scraped off by the contact members is required.

  Therefore, if the content of the binder resin in the charge transport layer, which is the surface layer, is increased in order to strengthen the surface layer and improve the durability, the photoresponsiveness decreases. This is because the charge transporting ability of the charge transporting material is low, so the charge transporting material in the charge transporting layer is diluted with an increase in the binder resin content, and the charge transporting ability of the charge transporting layer is further reduced, resulting in a light response. It will be worse. If the photoresponsiveness is poor, the residual potential increases and the surface potential of the photoreceptor is repeatedly attenuated, so that the surface charge of the portion that should be erased by exposure is sufficiently erased. This will cause problems such as image quality deterioration at an early stage. Therefore, there is a demand for a charge transport material that can ensure sufficient photoresponsiveness and is excellent in printing durability.

  In recent years, electrophotographic apparatuses such as digital copying machines and printers have been miniaturized and speeded up, and high sensitivity corresponding to high speed has been demanded as a photosensitive member characteristic. As the characteristics of the photoreceptor, it is required that the sensitivity does not decrease even when used in a low temperature environment, and the change in characteristics is small and the reliability is high under various environments. As a charge transport material, a higher charge transport capability is required. Further, since the time from exposure to development is short in a high-speed process, a photoconductor with good photoresponsiveness is required. As described above, since the photoresponsiveness depends on the charge transporting ability of the charge transporting substance, a charge transporting substance having a higher charge transporting ability is required from this point of view.

  As a charge transport material that satisfies these requirements, various molecular designs have been made, and compounds that incorporate an enamine group in part of the hydrazone structure and also have a styryl structure in order to broaden the conjugated system in the basic structure ( For example, Japanese Patent Laid-Open No. 6-59476 (see Patent Document 9) has been proposed. However, even these compounds have insufficient mechanical durability, and when used in a low temperature environment, the sensitivity is lowered, and there is a problem that must be improved in terms of exhibiting sufficient charge transport capability.

  In addition, an electrophotographic photosensitive member has been proposed which has a high sensitivity using a compound having a triarylamine structure similar to that of the present invention as a charge transport material and has little fluctuation in characteristics even when used repeatedly (for example, JP-A-5-150475). No. (Patent Document 10)). However, this compound also needs to increase the film thickness or increase the content of the binder resin at the expense of electrical characteristics in order to improve mechanical durability, and obtain characteristics satisfying all. There are still challenges.

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-A-6-59476 JP-A-5-150475

  The present invention provides a photoreceptor having excellent electrical characteristics such as sensitivity and photoresponsiveness, environmental stability, and excellent mechanical durability, an image forming apparatus equipped with the photoreceptor, a triarylamine dimer compound, and a method for producing the same. The task is to do.

  As a result of intensive research, the present inventors have surprisingly found that a photoconductor containing a triarylamine dimer compound having a specific substituent mode as a charge transport material has high sensitivity, high charging potential, and sufficient It has excellent photo-responsiveness, excellent mechanical durability, and there is no need to increase the binder resin content at the expense of electrical properties as when using ordinary charge transport materials. When it is used in the present invention, it is found that it maintains stable electrical characteristics and is excellent in printing durability, and is found to be extremely useful for a photoreceptor and an image forming apparatus equipped with the photoreceptor, thereby completing the present invention. It came to.

  Thus, according to the present invention, a single-layer photosensitive layer containing a charge generation material and a charge transport material or a charge generation layer containing a charge generation material and a charge transport on a conductive support made of a conductive material. A photoconductor formed by laminating a multilayer photosensitive layer having a charge transport layer containing a substance, wherein the single-layer photosensitive layer or the charge transport layer of the multilayer photosensitive layer is generally used as a charge transport material. Formula (1):

(Where
Ar ₁ and Ar ₂ are the same or different and are an arylene group which may have a substituent or a heterocyclic group which may have a substituent;
Ar ³ and Ar ⁴ are the same or different and are an aryl group which may have a substituent or a heterocyclic group which may have a substituent;
R ₁ and R ₂ are the same or different and are alkyl groups;
a and b are the same or different and are an alkyl group, a fluoroalkyl group, an alkoxy group, an amino group which may have a substituent, a halogen atom or a hydrogen atom, or an adjacent carbon atom of an aromatic ring to which they are bonded. -O-C-O- may be bonded to
m and n are integers of 1 to 4, and when m and n are 2 or more, a plurality of a and b may be the same or different.
An electrophotographic photosensitive member characterized by containing a triarylamine dimer compound represented by the formula:

  According to the present invention, the above-mentioned photoconductor, a charging unit for charging the photoconductor, an exposure unit for exposing the charged photoconductor, and an electrostatic latent image formed by the exposure are provided. An image forming apparatus including a developing unit for developing is provided.

Furthermore, according to the present invention, structural formula (I):
A triarylamine dimer compound characterized by the above is provided.

Furthermore, according to the present invention, structural formula (II):

And a bisaryl dihalogen compound derivative (1.0 equivalent) represented by the structural formula (III):

And a secondary amine compound (2.0 to 2.1 equivalents) represented by the following formula: 4.0 to 8.0 equivalents of copper powder, 8.0 to 12.0 equivalents of carbonate base, 0.2 A method for producing a triarylamine dimer compound is provided, wherein ˜0.8 equivalent of crown ether is added and reacted to obtain the triarylamine dimer compound according to claim 8.

The photoconductor of the present invention is a triarylamine dimer of the general formula (1) having an o-methyl-phenyl substituent which forms a broad conjugated system as a charge transport material for the photosensitive layer and has a large effect of improving printing durability. Since the compound is contained, the mechanical durability of the photosensitive layer is improved, there is no need to increase the content of the binder resin, the charging potential is high, the sensitivity is high, and sufficient photoresponsiveness is possible. Therefore, the present invention can provide a highly reliable electrophotographic photosensitive member that has high durability and does not deteriorate these characteristics even when used in a low-temperature environment or in a high-speed process.
Further, the image forming apparatus provided with the photoconductor of the present invention can provide a high-quality and highly reliable image under various environments.

  The photoreceptor of the present invention is a single-layer type photosensitive layer containing a charge generating material and a charge transport material on a conductive support made of a conductive material, or a charge generation layer and a charge transport material containing a charge generation material. An electrophotographic photosensitive member formed by laminating a multilayer photosensitive layer laminated with a charge transporting layer containing a charge transport layer, wherein the single-layer photosensitive layer or the charge transport layer of the multilayer photosensitive layer is used as a charge transporting substance. It contains a triarylamine dimer compound represented by the general formula (1).

  Among such triarylamine dimer compounds of general formula (1), sub-formula (2) in which a naphthyl group is introduced into the two N atoms:

(Wherein Ar ₁ , Ar ₂ , R ₁ , R ₂ , a, b, n and m are as defined in formula (1); d and e are as defined as a and b; o and p is an integer of 1 to 7, and when o and p are 2 or more, a plurality of d and e may be the same or different), and sub-formula (3):

(In the formula, Ar ₁ , R ₁ , R ₂ , a, b, n and m are as defined in the general formula (1); d, e, o and p are as defined in the sub formula (2). F and q have the same meanings as a and n in formula (1)
Is preferable because the production cost is relatively low.
In addition, the triarylamine dimer compound of the general formula (1) can be expected to be applied to a sensor, an EL element, an electrostatic recording element and the like as an organic photoconductive material.

The substituents in the general formula (1), sub formula (2) and sub formula (3) will be described.
Examples of the arylene group which may have a substituent for Ar ₁ and Ar ₂ include a phenylene group, a tolylene group, a methoxyphenylene group, a biphenylenyl group, a naphthylene group, and an anthrylene group.
Examples of the heterocyclic group which may have a substituent for Ar ₁ and Ar ₂ include, for example, an isobenzfuranidene group, a methylindazolidene group, a thionaphthalenediyl group, a furylidene group, a thienylidene group, a thiazolidene group, Examples include a redene group.

Examples of the aryl group that may have a substituent for Ar ³ and Ar ⁴ include a phenyl group, a naphthyl group, a tolyl group, a xylyl group, a methoxyphenyl group, a biphenyl group, a naphthyl group, and an anthryl group.
Examples of the heterocyclic group that may have a substituent for Ar ³ and Ar ⁴ include, for example, a benzodioxanyl group, an isobenzfuranyl group, a methylindazolyl group, a thionaphthalene group, a furyl group, a thienyl group, A thiazolyl group, a benzofuryl group, etc. are mentioned.

Examples of the alkyl group that may have a substituent for R ₁ and R ₂ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, and a butyl group.

As an alkyl group of a, b, d, e, and f, C1-C3 alkyl groups, such as a methyl group, an ethyl group, n-propyl group, an isopropyl group, are mentioned, for example.
Examples of the fluoroalkyl group of a, b, d, e and f include, for example, a monofluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a monofluoroethyl group, a pentafluoroethyl group, a monofluoropropyl, a heptafluoropropyl, etc. And a C1-C5 fluoroalkyl group.
As an alkoxy group of a, b, d, e, and f, C1-C3 alkyl groups, such as a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, are mentioned, for example.
Examples of the amino group which may have a and b substituents include an amino group, a dimethylamino group, a diethylamino group, and diisopropylamino.
Examples of the halogen atom for a, b, d, e and f include fluorine, chlorine, bromine and iodine, and fluorine is particularly preferred.

m, n and q are integers of 1 to 4, and when m and n are 2 or more, a plurality of a and b may be the same or different.
O and p are integers of 1 to 7, and when o and p are 2 or more, a plurality of d and e may be the same or different.

Although the specific example of the triarylamine dimer compound of General formula (1) is shown in Table 1, this invention is not limited by these.
Among these exemplary compounds, No. 1 1, 3, 7, 13 and 20 are particularly preferred.

  The triarylamine dimer compound of the general formula (1) of the present invention can be easily produced by the following synthesis process. That is, the general formula (4):

(In the formula, Ar ₁ and Ar ₂ have the same meaning as in the general formula (1); X is an iodine atom, a bromine atom or a chlorine atom)
And a bisaryl dihalogen compound derivative (1.0 equivalent) represented by the general formulas (5) and (6):

(In the formula, Ar ₃ , Ar ₄ , R ₁ , R ₂ , a, b, n and m have the same meanings as in the general formula (1)).
And 4.0 to 8.0 equivalents of copper powder in a solvent such as chlorobenzene, o-chlorobenzene or dimethyl sulfoxide; Add ˜12.0 equivalents of carbonate base such as potassium carbonate, sodium carbonate or calcium carbonate, 0.2 to 0.8 equivalents of crown ether such as 18-crown-6-ether, and vigorously heat and stir. Is synthesized by

  For example, the above exemplified compound No. 1 is a compound of the structural formula (I) as a bisaryl dihalogen compound derivative of the general formula (4), and a secondary amine compound of the general formulas (5) and (6) of the structural formulas (II) and (III). It can be produced using a compound.

Next, the structure of the photoconductor of the present invention will be described in detail, but the photoconductor of the present invention can be variously modified without departing from the gist thereof.
1 to 3 are schematic cross-sectional views showing the configuration of the main part of the photoreceptor of the present invention.
FIGS. 1 and 2 show a laminated type photosensitive member (hereinafter referred to as “functional separation type photosensitive member”) in which the photosensitive layer is a laminated photosensitive layer comprising a charge generation layer and a charge transport layer (hereinafter also referred to as “functional separation type photosensitive layer”). It is a schematic cross section which shows the structure of the principal part. Although a reverse two-layer stacked structure in which the charge generation layer and the charge transport layer are formed in reverse order may be used, the stacked type is preferable. In such a laminated type, it is possible to select an optimal material for each of the charge generation function and the charge transport function, so that it has higher sensitivity and high durability with increased stability during repeated use. A photoreceptor can be obtained.
FIG. 3 is a schematic cross-sectional view showing the configuration of the main part of a single-layer type photoreceptor that is a single-layer type photosensitive layer having a single photosensitive layer.

In the photoreceptor 1 of FIG. 1, a laminated photosensitive layer 14 in which a charge generation layer 12 and a charge transport layer 13 are laminated in this order is formed on the surface of a conductive support 11.
In the photoreceptor 2 of FIG. 2, an intermediate layer 15, a stacked photosensitive layer 14 in which a charge generation layer 12 and a charge transport layer 13 are stacked in this order are formed on the surface of a conductive support 11 in this order. Has been.
3, the intermediate layer 15 and the single-layer type photosensitive layer 140 are formed in this order on the surface of the conductive support 11.

[Conductive support 11]
The constituent material of the conductive support is not particularly limited as long as it is a material used in this field.
Specifically, metallic materials such as aluminum, aluminum alloys, copper, zinc, stainless steel, titanium: substrate surface made of polymer materials such as polyethylene terephthalate, polyamide, polyester, polyoxymethylene, polystyrene, hard paper, glass, etc. And metal foil laminated, metal material deposited, conductive polymer, tin oxide, indium oxide or other conductive compound layer deposited or applied.

The shape of the conductive support is not limited to a sheet shape as shown in FIGS. 1 to 3, and may be a cylindrical shape, a columnar shape, an endless belt shape, or the like.
If necessary, the surface of the conductive support is subjected to irregular reflection treatment such as anodizing film treatment, surface treatment with chemicals, hot water, coloring treatment, and surface roughening within a range that does not affect the image quality. May be given.

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

[Laminated Photosensitive Layer 14]
The laminated photosensitive layer is composed of a charge generation layer 12 and a charge transport layer 13.

[Charge generation layer 12]
The charge generation layer contains a charge generation material and a binder resin.
As the charge generation material, a compound used in this field can be used.
Specifically, azo pigments (monoazo pigments, bisazo pigments, trisazo pigments, etc.), indigo pigments (indigo, thioindigo, etc.), perylene pigments (perylene imide, perylene acid anhydride, etc.), polycyclic quinone pigments Pigments (anthraquinone, pyrenequinone, etc.), phthalocyanine pigments (metal phthalocyanine, X-type metal-free phthalocyanine, etc.), organic pigments or dyes such as squarylium dyes, pyrylium salts, thiopyrylium salts, triphenylmethane dyes, selenium, amorphous Examples thereof include inorganic materials such as silicon. These charge generating materials can be used alone or in combination of two or more.

Among these charge generation materials, phthalocyanine pigments such as metal phthalocyanine and X-type metal-free phthalocyanine are preferable, and Bragg angle (2θ ± 0.2 °) in Cu-Kα characteristic X-ray diffraction (wavelength: 1 to 54 °). Is particularly preferred oxotitanium phthalocyanine having a diffraction peak at least 27.2 °.
Since phthalocyanine pigments have high charge generation efficiency and charge injection efficiency, they generate a large amount of charge by absorbing light, and in the single layer type photosensitive layer without accumulating the generated charge in the molecule. Since charges are efficiently injected into the contained charge transport material and smoothly transported, a highly sensitive and high resolution photoreceptor can be obtained. This effect is the same for the single-layer type photoreceptor described later.

Charge generating materials can be used in combination with sensitizing dyes.
Examples of such sensitizing dyes include triphenylmethane dyes typified by methyl violet, crystal violet, knight blue and victoria blue; acridines typified by erythrosine, rhodamine B, rhodamine 3R, acridine orange and frappeosin. Dyes; thiazine dyes typified by methylene blue and methylene green; oxazine dyes typified by capri blue and meldra blue; cyanine dyes; styryl dyes; pyrylium salt dyes and thiopyrylium salt dyes. As such an optical sensitizer, a pigment such as a quinoline pigment may be used.

As the binder resin, for example, it is used for the purpose of improving the mechanical strength, durability and the like of the charge generation layer, and a resin having a binding property used in this field can be used, and is compatible with the diamine compound of the present invention. What is excellent in is preferable.
Specifically, vinyl resins such as polymethyl methacrylate, polystyrene, polyvinyl chloride, polycarbonate, polyester, polyester carbonate, polysulfone, polyarylate, polyamide, methacrylic resin, acrylic resin, polyether, polyacrylamide, polyphenylene oxide, etc. Thermoplastic resin: Thermosetting resin such as phenoxy resin, epoxy resin, silicone resin, polyurethane, phenol resin, alkyd resin, melamine resin, phenoxy resin, polyvinyl butyral, polyvinyl formal, partially cross-linked products of these resins, these resins Copolymer resins containing two or more of the structural units contained in (vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, acrylo Tolyl - insulating resin such as styrene copolymer resin). These binder resins can be used alone or in combination of two or more.

Among these resins, polystyrene, polycarbonate, polyarylate, and polyphenylene oxide are particularly excellent in compatibility with the diamine compound of the present invention, and further have a volume resistance of 10 ¹³ Ω or more, excellent electrical insulation, and composition. Polycarbonate is particularly preferred because it is excellent in film properties, potential characteristics, and the like.

The use ratio of the charge generation material and the binder resin is not particularly limited. Preferably, the charge generation material is contained in an amount of 10 to 99% by weight in the total amount of the charge generation material and the binder resin, and the balance is the binder resin. It is.
If the ratio of the charge generation material is less than 10% by weight, the sensitivity may be lowered. Conversely, if the ratio of the charge generation material exceeds 99% by weight, not only the film strength of the charge generation layer is decreased, but also the charge generation. This is called a black spot where the dispersibility of the substance decreases and the coarse particles increase, the surface charge other than that which should be erased by exposure decreases, and image defects, especially toner adheres to the white background and minute black spots are formed. There is a possibility that a lot of fogging of the image occurs.

  In addition to the two essential components, the charge generation layer may be one or more selected from a hole transport material, an electron transport material, an antioxidant, a dispersion stabilizer, a sensitizer, and the like, if necessary. Each may contain an appropriate amount. As a result, the potential characteristics are improved, the stability of the coating solution for forming a charge generation layer, which will be described later, is increased, fatigue deterioration during repeated use of the photoreceptor is reduced, and durability can be improved.

  The charge generation layer 12 is prepared by dissolving or dispersing a charge generation material, a binder resin and, if necessary, other additives in an appropriate organic solvent to prepare a coating solution for forming a charge generation layer. It can be formed by applying to the surface of the body 11 or the surface of the intermediate layer 15 formed on the conductive support 11 and then drying to remove the organic solvent. More specifically, for example, a charge generating layer forming coating solution is prepared by dissolving or dispersing a charge generating substance and other additives as required in a resin solution obtained by dissolving a binder resin in an organic solvent. To do.

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

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

Examples of the coating method of the charge generation layer forming coating solution include a roll coating method, a spray coating method, a blade coating method, a ring coating method, and a dip coating method.
The dip coating method is a method of forming a layer on the conductive support 11 by immersing the conductive support 11 in a coating tank filled with a coating solution, and then pulling it up at a constant speed or a sequentially changing speed. . Since this method is relatively simple and excellent in terms of productivity and cost, it is widely used for producing an electrophotographic photosensitive member. In addition, you may provide the coating liquid dispersion | distribution apparatus represented by the ultrasonic generator in the apparatus used for the dip coating method in order to stabilize the dispersibility of a coating liquid.
Alternatively, the charge generating material may be deposited on the conductive support by a known method such as a vacuum deposition method without using the binder resin.

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

[Charge transport layer 13]
The charge transport layer contains one or more triarylamine dimer compounds of the general formula (1) as a charge transport material and a binder resin.
The charge transport layer may contain other charge transport materials as long as the effects of the present invention are not impaired. However, in order to achieve a particularly high charge transport capability, the total amount of the charge transport material is preferably the triarylamine dimer compound of the general formula (1).

  Other charge transport materials include enamine compounds such as enamine-styryl derivatives, enamine-hydrazone derivatives, enamine-butadiene derivatives, enamine-hexatriene derivatives, 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, acridines Derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, triarylmethane derivatives, phenylene diene Min derivatives, stilbene derivatives and benzidine derivatives. Also included are polymers having groups derived from these compounds in the main chain or side chain, such as poly-N-vinylcarbazole, poly-1-vinylpyrene and poly-9-vinylanthracene.

  As the binder resin, one or more of the same binder resins as those contained in the charge generation layer can be used.

The use ratio of the charge transport material and the binder resin is not particularly limited, but when the weight M of the charge transport material and the weight B of the binder resin are used, the ratio A / B is 10/8 to 10/30. Is preferred. Since the triarylamine dimer compound of the general formula (1) has a high charge mobility, the photoresponsiveness can be maintained even when a binder resin is added at a higher ratio than when a conventionally known charge transport material is used.
When the ratio A / B is less than 10/30 and the binder resin ratio is high, when the charge transport layer is formed by the dip coating method, the viscosity of the coating liquid increases, the coating speed decreases, and the productivity is remarkably increased. May be worse. Further, if the amount of the solvent in the coating solution is increased in order to suppress an increase in the viscosity of the coating solution, a brushing phenomenon occurs and the formed charge transport layer may become cloudy.
On the other hand, when the ratio A / B exceeds 10/8 and the binder resin ratio is low, the printing durability is lowered as compared with the case where the binder resin ratio is high, and the wear amount of the photosensitive layer may be increased.

In addition to the two essential components, the charge transport layer may contain additives such as a plasticizer or a leveling agent as necessary in order to improve film formability, flexibility, and surface smoothness. .
Examples of the plasticizer include dibasic acid esters, fatty acid esters, phosphate esters, phthalate esters, chlorinated paraffins, and epoxy type plasticizers.
As a leveling agent, a silicone type leveling agent etc. are mentioned, for example.
In addition, the charge transport layer may contain fine particles of an inorganic compound or an organic compound in order to enhance mechanical strength and improve electrical characteristics.
Furthermore, the charge transport layer may contain additives such as an antioxidant and a sensitizer as necessary. As a result, the potential characteristics are improved, the stability as a coating solution is increased, the fatigue deterioration when the photoreceptor is repeatedly used can be reduced, and the durability can be improved.

As the antioxidant, a hindered phenol derivative, a hindered amine derivative, and a mixture thereof are preferably used, and are preferably used in the range of 0.1% by mass to 50% by mass with respect to the charge transport material.
If the amount of the antioxidant used is less than 0.1% by mass, sufficient effects may not be obtained for improving the stability of the coating solution and improving the durability of the photoreceptor. On the other hand, if the amount of the antioxidant used exceeds 50% by mass, the photoreceptor characteristics may be adversely affected.

The charge transport layer 13 is prepared by dissolving or dispersing a charge transport material, a binder resin and, if necessary, other additives in an appropriate organic solvent to prepare a coating solution for forming a charge transport layer. It can be formed by applying to the surface of 12 and then drying to remove the organic solvent. More specifically, for example, a charge transport layer is formed by dissolving or dispersing a charge transport material, a charge transport material and other additives as required in a resin solution obtained by dissolving a binder resin in an organic solvent. A coating solution is prepared.
Other processes and conditions are in accordance with the formation of the charge generation layer.

  Although the film thickness of a charge transport layer is not specifically limited, 5-50 micrometers is preferable and 10-40 micrometers is especially preferable. If the thickness of the charge transport layer is less than 5 μm, the charge holding ability on the surface of the photoreceptor may be lowered. Conversely, if the thickness of the charge transport layer exceeds 50 μm, the resolution of the photoreceptor may be lowered.

[Single-layer type photosensitive layer 140]
The single-layer type photosensitive layer contains a charge generation material, a charge transport material, and a binder resin.
As the charge generation material, one or more of the same charge generation materials as those contained in the charge generation layer of the laminated photosensitive layer can be used.
As the charge transport material, one or more of the same charge transport materials as those contained in the charge transport layer of the laminated photosensitive layer can be used.
As the binder resin, one or more of the same binder resins as those contained in the laminated photosensitive layer can be used.
The usage ratio of the charge generation material and the binder resin and the usage ratio of the charge transport material and the binder resin are the same as in the case of forming the charge generation layer and the charge transport layer of the laminated photosensitive layer.
The single-layer type photosensitive layer may contain various additives as necessary in addition to the two essential components, and includes one or more of the same additives as those contained in the laminated photosensitive layer. Can be used.

  Although the film thickness of a single layer type photosensitive layer is not specifically limited, 5-100 micrometers is preferable and 10-50 micrometers is especially preferable. If the film thickness of the single-layer type photosensitive layer is less than 5 μm, the charge holding ability on the surface of the photoreceptor may be lowered. Conversely, if the film thickness of the single-layer type photosensitive layer exceeds 100 μm, the productivity of the photoreceptor is reduced. There is a risk.

In addition, the single-layer type photosensitive layer and the multilayer type photosensitive layer further contain one or more electron-accepting substances and the above dyes in order to improve sensitivity and suppress an increase in residual potential and fatigue during repeated use. But you can.
Examples of the electron acceptor include acid anhydrides such as succinic anhydride, maleic anhydride, phthalic anhydride and 4-chloronaphthalic anhydride, cyano compounds such as tetracyanoethylene and terephthalmalondinitrile, 4-nitrobenzaldehyde and the like. Aldehydes, anthraquinones such as anthraquinone and 1-nitroanthraquinone, polycyclic or heterocyclic nitro compounds such as 2,4,7-trinitrofluorenone and 2,4,5,7-tetranitrofluorenone, and diphenoquinone compounds And those obtained by polymerizing these electron-withdrawing materials.

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

The intermediate layer is formed, for example, by dissolving a resin material in an appropriate solvent to prepare a coating solution for forming an intermediate layer, applying this coating solution to the surface of the conductive support, and removing the organic solvent by drying. it can.
Examples of the resin material include natural polymeric materials such as casein, gelatin, polyvinyl alcohol, and ethyl cellulose in addition to the same binder resin as that contained in the photosensitive layer, and one or more of these can be used. .
Examples of the solvent for dissolving or dispersing the resin material include water, alcohols such as methanol, ethanol and butanol, glymes such as methyl carbitol and butyl carbitol, and mixed solvents in which two or more of these solvents are mixed. Can be mentioned.
Other processes and conditions are in accordance with the formation of each photosensitive layer.

Moreover, the coating liquid for intermediate | middle layer formation may contain the metal oxide particle.
The metal oxide particles can easily adjust the volume resistivity of the intermediate layer, further suppress charge injection into the single-layer type photosensitive layer or multilayer type photosensitive layer, and maintain the electrical characteristics of the photoconductor in various environments. it can.
Examples of the metal oxide particles include titanium oxide, aluminum oxide, aluminum hydroxide, and tin oxide.
When the total content of the resin material and the metal oxide particles in the coating liquid for forming the intermediate layer is C and the content of the solvent is D, the volume ratio (C / D) of both is 1/99 to 40/60. (Weight ratio = 0.01 to 0.67) is preferable, and 2/98 to 30/70 (weight ratio = 0.02 to 0.43) is particularly preferable.
The volume ratio (E / F) of the resin material content (E) and the metal oxide particle content (F) is 1/99 to 90/10 (weight ratio = 0.01 to 9.0). ) Is preferable, and 5/95 to 70/30 (weight ratio = 0.05 to 2.33) is particularly preferable.

Although the film thickness of an intermediate | middle layer is not specifically limited, 0.01-20 micrometers is preferable and 0.1-10 micrometers is especially preferable. If the thickness of the intermediate layer is less than 0.01 μm, it may not function substantially as the intermediate layer, and there is a possibility that a uniform surface cannot be obtained by covering the defects of the conductive support, and the thickness of the intermediate layer is 20 μm. If it exceeds 1, it is difficult to form a uniform intermediate layer, and the sensitivity of each photoreceptor may be lowered.
In addition, when the constituent material of an electroconductive support body is aluminum, the layer (alumite layer) containing an alumite can be formed and it can be set as an intermediate | middle layer.

[Surface protective layer (not shown)]
The photoreceptor of the present invention preferably has a surface protective layer on a single layer type photosensitive layer or a multilayer type photosensitive layer. The surface protective layer has a function of improving the durability (printing durability) of the photoconductor, and chemically applies to each photoconductive layer such as ozone and nitrogen oxide generated by corona discharge when charging the surface of the photoconductor. Adverse effects can be prevented.
The surface protective layer contains, for example, a binder resin, an inorganic filler-containing resin, an inorganic oxide, a charge transport material, and the like.
As the charge transport material, one or more of the same charge transport materials as those contained in the photosensitive layer can be used.
As the binder resin, one or more of the same binder resins as those contained in the single-layer type photosensitive layer can be used.

For example, the surface protective layer 5 is prepared by dissolving or dispersing a charge transport material and a binder resin in a suitable organic solvent to prepare a coating solution for forming a surface protective layer. It can be formed by coating on the surface of the layer 140 or the laminated photosensitive layer 14 and removing the organic solvent by drying. As the organic solvent used here, the same organic solvent used for forming the photosensitive layer can be used.
Other processes and conditions are in accordance with the formation of each photosensitive layer.
The thickness of the surface protective layer 5 is not particularly limited, but is preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm. If the thickness of the surface protective layer 5 is less than 0.5 μm, the surface resistance of the photoreceptor is inferior and the durability may be insufficient. Conversely, if it exceeds 10 μm, the resolution of the photoreceptor may be reduced. There is.

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

The image forming apparatus of the present invention will be described with reference to the drawings, but is not limited to the following description.
FIG. 4 is a schematic side view showing the configuration of the image forming apparatus of the present invention.
An image forming apparatus 100 in FIG. 4 includes a photoreceptor 10 of the present invention (for example, the photoreceptors 1 to 3 in FIGS. 1 to 3), a charging unit (charger) 32, an exposure unit 30, and a developing unit (developing unit). ) 33, a transfer device (transfer charging device) 34, a cleaner 36, and a fixing device 35. Reference numeral 51 indicates a transfer sheet.

  The photosensitive member 10 has a cylindrical shape, is rotatably supported by the main body of the image forming apparatus 100 (not shown), and is driven to rotate in the direction of the arrow 41 around the rotation axis 44 by a driving unit (not shown). The driving means is configured to include, for example, an electric motor and a reduction gear, and transmits the driving force to a conductive support constituting the core of the photoconductor 10, thereby rotating the photoconductor 10 at a predetermined peripheral speed. . The charger 32, the exposure means 30, the developing device 33, the transfer device 34, and the cleaner 36 are arranged in this order along the outer peripheral surface of the photoconductor 10 from the upstream side in the rotation direction of the photoconductor 10 indicated by the arrow 41. It is provided toward the side. A fixing device 35 is provided in the traveling direction of the transfer paper 51.

The charger 32 is a charging unit that charges the outer peripheral surface 43 of the photoreceptor 10 to a predetermined positive or negative potential. In the present embodiment, the charger 32 is realized by a contact-type charging roller 32a and a bias power source 32b that applies a voltage to the charging roller 32a.
As the charging means, a non-contact charger wire can be used. However, in a charging roller that requires high abrasion resistance on the surface of the photoreceptor, the photoreceptor having the surface protective layer according to the present invention has a greater effect on improving durability. To demonstrate.
Therefore, in the image forming apparatus of the present invention, the charging means is preferably contact charging.

  The exposure unit 30 includes, for example, a semiconductor laser as a light source, and is charged by irradiating light 31 such as a laser beam output from the light source between the charger 32 and the developer 33 of the photoconductor 10. The outer peripheral surface 43 of the photoconductor 10 is exposed according to image information. The light 31 is repeatedly scanned in the main scanning direction in the extending direction (longitudinal direction) of the rotation axis 44 of the photoconductor 10, and accordingly, electrostatic latent images are sequentially formed on the surface 43 of the photoconductor 10.

  The developing device 33 is a developing unit that develops the electrostatic latent image formed on the surface 43 of the photoconductor 10 by exposure with a developer. The developing device 33 is provided facing the photoconductor 10 and has toner on the outer peripheral surface of the photoconductor 10. And a casing 33b that supports the developer roller 33a so as to be rotatable about a rotation axis parallel to the rotation axis 44 of the photosensitive member 10 and accommodates a developer containing toner in the internal space thereof.

  The transfer unit 34 transfers a toner image, which is a visible image formed on the outer peripheral surface of the photoconductor 10 by development, from the direction of the arrow 42 by a conveying unit (not shown) in synchronization with exposure to the photoconductor 10. It is a transfer means for transferring onto a transfer paper 51 which is a recording medium supplied between the transfer device 34. The transfer unit 34 is, for example, a non-contact type transfer unit that includes a charging unit and transfers the toner image onto the transfer paper 51 by applying a charge having a polarity opposite to that of the toner to the transfer paper 51.

  The cleaner 36 is a cleaning unit that removes and collects toner remaining on the outer peripheral surface 43 of the photoconductor 10 after the transfer operation by the transfer device 34, and a cleaning blade 36a that peels off toner remaining on the outer peripheral surface of the photoconductor 10. A recovery casing 36b for storing the toner separated by the cleaning blade 36a. The cleaner 27 is provided together with a charge eliminating lamp (not shown).

  Further, the image forming apparatus 100 is provided with a fixing device 35 as fixing means for fixing the transferred image on the downstream side where the transfer paper 51 that has passed between the photoreceptor 10 and the transfer device 34 is conveyed. . The fixing device 35 includes a heating roller 35a having a heating unit (not shown), and a pressure roller 35b that is provided facing the heating roller 35a and is pressed by the heating roller 35a to form a contact portion.

  The image forming operation by the image forming apparatus 100 is performed as follows. First, when the photosensitive member 10 is rotationally driven in the direction of the arrow 41 by the driving unit, the photosensitive member is provided by the charger 32 provided on the upstream side in the rotational direction of the photosensitive member 10 with respect to the imaging point of the light 31 by the exposure unit 30. 10 surfaces are uniformly charged to a positive or negative predetermined potential.

Next, light 31 corresponding to image information is irradiated from the exposure unit 32 to the surface of the photoreceptor 10. With this exposure, the surface charge of the portion irradiated with the light 31 is removed from the photoreceptor 10, 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.
Toner is supplied to the surface of the photoreceptor 10 on which the electrostatic latent image is formed from a developing device 33 provided on the downstream side in the rotation direction of the photoreceptor 10 with respect to the image forming point of the light 31 by the exposure means 30. The image is developed to form a toner image.

In synchronization with the exposure of the photoconductor 10, the transfer paper 51 is supplied between the photoconductor 10 and the transfer device 34. The transfer device 34 applies a charge having a polarity opposite to that of the toner to the supplied transfer paper 51, and the toner image formed on the surface of the photoreceptor 10 is transferred onto the transfer paper 51.
The transfer paper 51 onto which the toner image has been transferred is conveyed to the fixing device 35 by the conveying means, and is heated and pressurized when passing through the contact portion between the heating roller 35a and the pressure roller 35b of the fixing device 35, and the toner The image is fixed on the transfer paper 51 and becomes a robust image. The transfer paper 51 on which the image is formed in this way is discharged to the outside of the image forming apparatus 100 by the conveying means.

  On the other hand, the toner remaining on the surface of the photoconductor 10 after the transfer of the toner image by the transfer unit 34 is peeled off from the surface of the photoconductor 10 by the cleaner 36 and collected. The charge on the surface of the photoconductor 10 from which the toner has been removed in this way is removed by the light from the static elimination lamp, and the electrostatic latent image on the surface of the photoconductor 10 disappears. Thereafter, the photoconductor 10 is further driven to rotate, and a series of operations starting from charging is repeated to form images continuously.

  The image forming apparatus 100 according to the present invention includes the photoconductor 10 having the photosensitive layer in which the triarylamine dimer compound of the general formula (1) is uniformly dispersed as a charge transport material, and thus has high quality without image defects such as black spots. Images can be formed.

  Therefore, according to the present invention, it is possible to provide a highly reliable image forming apparatus capable of forming a high-quality image under various environments. In addition, since the photoconductor of the present invention does not deteriorate in performance due to light exposure, the image quality can be prevented from being deteriorated due to exposure of the photoconductor to light during maintenance, and the reliability of the image forming apparatus can be improved. Can do.

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

(Chemical structure)
Nuclear magnetic resonance apparatus: NMR (Bruker Biospin, model: DPX-200)
Sample preparation About 4mg / 0.4m (CDCl3)
Measurement mode ¹ H (normal), ¹³ C (normal, DPET-135)

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

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

Production Example 1 Synthesis of Triarylamine Dimer Compound (Exemplary Compound No. 1)
In 100 ml of o-dichlorobenzene, 4.75 g (2.0 equivalents) of 2,4-xylyl-β-naphthylamine, 2.98 g (1.0 equivalent) of 4,4′-dibromobiphenyl, 18-crown-6 1.02 g (0.2 eq) of ether, 4.9 g (4.0 eq) of copper powder and 21.3 g (8.0 eq) of anhydrous potassium carbonate were mixed, the reaction temperature was raised to 180 ° C., and this temperature was increased. The reaction was stirred and refluxed for 18 hours with heating to maintain. After completion of the reaction, hot Celite filtration was performed, the filtrate was concentrated, and the residue was purified by silica gel column chromatography to obtain 4.95 g of a white powder compound.

The obtained white powdery compound was analyzed for chemical structure, molecular weight and elements.
Nuclear magnetic resonance equipment: NMR
¹ H-NMR spectrum (ordinary) showed δ = 2.06 (S, 6H), 2.38 (S, 6H), 6.97 to 7.82 (m, 28H).
The ¹³ C-NMR spectrum (usually DEPT-135) has δ = 18.66 (CH3,4C), 21.76 (CH3,4C), 117.00 (CH, 2C), 121.96 (CH, 4C), 122.72 (CH, 2C), 124.00 (CH, 2C), 126.35 (CH, 2C), 126.87 (CH, 2C), 127.21 (CH, 4C), 127.66 (CH, 2C), 128.31 (CH, 2C), 128.78 (CH, 2C) ), 129.48 (C, 2C), 129.59 (CH, 2C), 132.60 (CH, 2C), 133.95 (C, 2C), 134.64 (C, 2C), 136.06 (C, 2C), 136.33 (C, 2C) 142.77 (C, 2C), 145.26 (C, 2C), and 146.46 (C, 2C).

5-7, each ¹ H-NMR spectrum chart, a ¹³ C-NMR spectrum chart of normal ¹³ C-NMR spectrum chart and DEPT-135. These NMR signals are obtained from Example Compound No. 1 which is the target benzofuran-amine compound. 1 structure is well supported.

In addition, molecular weight measuring apparatus: LC-MS is an example compound No. A peak corresponding to a molecular ion [M + H] ⁺ in which a proton is added to 1 (calculated molecular weight: 644.32) was observed at 645.5.

Furthermore, the elemental analysis values of the white powdery compound were as follows.
<Exemplary Compound No. Elemental analysis value of 1>
Theoretical value C: 89.40%, H: 6.25%, N: 4.34%
Actual value C: 89.04%, H: 5.97%, N: 4.01%
As described above, from the results of analysis such as NMR, LC-MS, and elemental analysis, the obtained white powdery compound was identified as Exemplified Compound No. 1 triarylamine dimer compound (yield: 80.1%). Moreover, the purity of the obtained exemplary compound (1) was 99.0% from the analysis result of HPLC at the time of LC-MS measurement.

(Production Examples 2 to 5) Synthesis of Exemplified Compounds No. 3, 7, 13, and 20 In Production Example 1, the bisaryl dihalogen compound derivative represented by the general formula (4) and the secondary amine compound represented by the general formula (5) The same operation was carried out using each raw material compound shown in Table 2, and Exemplified Compound No. 3, 7, 13 and 20 were prepared, respectively. In Table 2, Exemplified Compound No. 1 raw material compounds are also shown.

In addition, Table 3 shows the elemental analysis values, the calculated molecular weight values, and the actually measured values [M + H] obtained by LC-MS of the respective exemplary compounds obtained in Production Examples 1 to 5.

Example 1
Exemplified Compound No. 1 which is an asymmetric bishydroxy compound according to the present invention produced in Production Example 1 as follows. An electrophotographic photoreceptor using 1 as a charge transport material for the charge transport layer was prepared.
As the conductive support, a polyethylene terephthalate (abbreviated as PET) film having a thickness of 100 μm deposited with aluminum (hereinafter referred to as “aluminum-deposited PET film”) was used.

  7 parts by weight of titanium oxide (trade name: Taibake TTO55A, manufactured by Ishihara Sangyo Co., Ltd.) and 13 parts by weight of copolymer nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.), 159 parts by weight of methyl alcohol and 1,3- In addition to a mixed solvent with 106 parts by weight of dioxolane, dispersion treatment was performed for 8 hours with a paint shaker to prepare 100 g of an intermediate layer forming coating solution. This coating solution for forming an intermediate layer was applied to the aluminum surface of an aluminum vapor-deposited PET film, which is a conductive support, by an applicator and naturally dried to form an intermediate layer having a thickness of 1 μm.

  Next, 1 part by weight of X-type metal-free phthalocyanine (Fastogen Blue 8120, manufactured by Dainippon Ink and Co., Ltd.) and 1 part by weight of butyral resin (trade name: # 6000-C, manufactured by Denki Kagaku Kogyo Co., Ltd.) are added to 98 parts by weight of methyl ethyl ketone. The mixture was mixed and dispersed with a paint shaker to prepare 50 g of a charge generation layer forming coating solution. This charge generation layer forming coating solution was applied to the surface of the previously provided intermediate layer in the same manner as the above intermediate layer and naturally dried to form a charge generation layer having a thickness of 0.4 μm.

  Next, Exemplified Compound No. 1 produced in Production Example 1 was used. 8 parts by mass of 1 compound and 10 parts by mass of a polycarbonate resin (manufactured by Teijin Chemicals Ltd .: C-1400) were dissolved in 80 parts by mass of THF to prepare a coating solution for a charge transport layer. This coating solution for charge transport layer was applied onto the charge generation layer previously formed by a baker applicator and then dried to form a charge transport layer having a thickness of 10 μm. As described above, a laminated electrophotographic photosensitive member having the structure shown in FIG. 1 was produced.

(Example 2)
Exemplified compound No. 1 as a charge transport material. In place of Exemplified Compound No. 1 shown in Table 1 An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the compound No. 3 was used.

(Examples 3 to 5)
Exemplified compound No. 1 as a charge transport material. In place of Exemplified Compound No. 1 shown in Table 1 Three types of electrophotographic photosensitive members were produced in the same manner as in Example 1 except that the compounds 7, 13, and 20 were used.

(Comparative Example 1)
Exemplified compound No. 1 as a charge transport material. Instead of 1, an attempt was made to produce an electrophotographic photoreceptor in the same manner as in Example 1 except that a compound α-Np-TPD (manufactured by Tokyo Chemical Industry Co., Ltd.) having a triarylamine structure was used. However, α-Np-TPD was not dissolved in the system used, and an electrophotographic photosensitive member could not be obtained.

(Comparative Example 2)
Exemplified compound No. 1 as a charge transport material. Instead of 1, an electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that a compound having a triarylamine structure 4 mM-TPD (manufactured by Takasago Fragrance Co., Ltd.) was used.
(Comparative Example 3)
Exemplified compound No. 1 as a charge transport material. Instead of 1, a compound having a triarylamine structure 4 mM-TPD (manufactured by Takasago Fragrance Co., Ltd.) is used, and the ratio M / B of the charge transport material weight M to the binder resin weight B is 10/20. Produced an electrophotographic photoreceptor in the same manner as in Example 1.

<Electrical characteristics evaluation>
About each electrophotographic photosensitive member obtained in Examples 1 to 5 and Comparative Examples 1 to 3, using an electrostatic paper test apparatus (trade name: EPA-8200, manufactured by Kawaguchi Electric Co., Ltd.), the following is performed. The electrical characteristics were evaluated.
The surface of the photoreceptor was charged by applying a minus (−) 5 kV voltage to the photoreceptor, and the surface potential of the photoreceptor at this time was measured as a charged potential V0 [V]. Next, the charged photoreceptor surface was exposed to light, and the exposure amount required to halve the surface potential of the photoreceptor from the charging potential V0 was measured as a half exposure amount E1 / 2 [μJ / cm ² ]. . Further, the surface potential of the photosensitive member at the time when 10 seconds passed from the start of exposure was measured as a residual potential Vr [V]. For the exposure, light having a wavelength of 780 nm and intensity of 1 μW / cm ² obtained by spectroscopy with a monochromator was used.

<Evaluation of printing durability>
The electrophotographic photoreceptors obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were evaluated for printing durability and electrical property stability as follows.
Each produced electrophotographic photosensitive member was mounted on a digital copying machine (manufactured by Sharp Corporation: AR-M450) with a process speed of 225 mm / sec. After 50,000 images were formed, the film thickness d1 of the photosensitive layer was measured, and the difference between this value and the film thickness d0 of the photosensitive layer at the time of production was obtained as a film reduction amount Δd (= d0−d1). An evaluation index for printing durability was used.
These evaluation results are shown in Table 4.

The photoreceptors of Examples 1 to 5 in which the triarylamine dimer compound of the present invention was used for the charge transport layer had good electrical characteristics and mechanical durability, and little wear.
The photoreceptor of Comparative Example 2 was found to be significantly inferior to the photoreceptors of Examples 1 to 5 in the printing durability test, although the initial electrical characteristics were good.
Although the photoconductor of Comparative Example 3 in which the ratio of the binder resin to the charge transport material was increased, the mechanical printing durability was improved, but the Vr increased due to the decrease in the content of the charge transport material in the photosensitive layer. The characteristics deteriorated.

FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of the multilayer photoconductor of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of the multilayer photoconductor of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of a single layer type photoreceptor of the present invention. 1 is a schematic side view illustrating a configuration of an image forming apparatus of the present invention. Exemplified Compound Nos. 1 is a ¹ H-NMR spectrum chart of 1. FIG. Exemplified Compound Nos. 1 is a normal ¹³ C-NMR spectrum chart of 1. FIG. Exemplified Compound Nos. 1 is a ¹³ C-NMR spectrum chart of 1 DEPT-135. FIG.

Explanation of symbols

1, 2, 3 Photoconductor 11 Conductive support 12 Charge generation layer 13 Charge transport layer 14 Multilayer photosensitive layer 15 Intermediate layer 140 Single layer type photosensitive layer

DESCRIPTION OF SYMBOLS 10 Photoconductor 30 Exposure means 31 Light 32 Charging means (charger)
32a Charging roller 32b Bias power supply 33 Developing means (developer)
33a Developing roller 33b Casing 34 Transfer device (transfer charger)
35 Fixing Device 35a Heating Roller 35b Pressure Roller 36 Cleaner 36a Cleaning Blade 36b Recovery Casing 41, 42 Arrow 43 Outer Surface (Surface)
44 Rotating axis 51 Transfer paper 100 Image forming apparatus

Claims (9)

A monolayer type photosensitive layer containing a charge generating substance and a charge transporting substance on a conductive support made of a conductive material, or a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance; An electrophotographic photosensitive member in which a multi-layered photosensitive layer is laminated, wherein the single-layer type photosensitive layer or the charge-transporting layer of the multi-layered photosensitive layer is represented by the general formula (1):
(Where
Ar ₁ and Ar ₂ are the same or different and are an arylene group which may have a substituent or a heterocyclic group which may have a substituent;
Ar ₃ and Ar ₄ are the same or different and are an aryl group which may have a substituent or a heterocyclic group which may have a substituent;
R ₁ and R ₂ are the same or different and are alkyl groups;
a and b are the same or different and are an alkyl group, a fluoroalkyl group, an alkoxy group, an amino group which may have a substituent, a halogen atom or a hydrogen atom, or an adjacent carbon atom of an aromatic ring to which they are bonded. -O-C-O- may be bonded to
m and n are integers of 1 to 4, and when m and n are 2 or more, a plurality of a and b may be the same or different.
An electrophotographic photoreceptor comprising a triarylamine dimer compound represented by the formula: The triarylamine dimer compound has the sub-formula (2):
(Where
Ar ₁ , Ar ₂ , R ₁ , R ₂ , a, b, n and m have the same meanings as those in the general formula (1);
d and e are synonymous with a and b;
o and p are integers of 1 to 7, and when o and p are 2 or more, a plurality of d and e may be the same or different.
The electrophotographic photosensitive member according to claim 1, which is represented by: The triarylamine dimer compound is a sub-formula (3):
(Where
Ar ₁ , R ₁ , R ₂ , a, b, n and m have the same meanings as in general formula (1);
d, e, o and p are as defined in sub-formula (2);
f and q have the same meanings as a and n in formula (1))
The electrophotographic photosensitive member according to claim 1, which is represented by:   The charge transport layer contains a binder resin, and the ratio M / B between the weight M of the charge transport material and the weight of the binder resin is 10/8 to 10/30. The electrophotographic photoreceptor described in 1.   The charge generation layer of the single layer type photosensitive layer or the multilayer type photosensitive layer has a Bragg angle (2θ ± 0.2 °) in Cu-Kα characteristic X-ray diffraction (wavelength: 1.54Å) as the charge generation material. The electrophotographic photoreceptor according to claim 1, which contains oxotitanium phthalocyanine having a diffraction peak at least at 27.2 °.   The electrophotographic photosensitive member according to claim 1, further comprising an intermediate layer between the conductive support and the single-layer photosensitive layer or the laminated photosensitive layer.   An electrophotographic photosensitive member according to any one of claims 1 to 6, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member, and exposure An image forming apparatus comprising: a developing unit that develops the electrostatic latent image formed by the step. Structural formula (I):
The triarylamine dimer compound characterized by these. Structural formula (II):
And a bisaryl dihalogen compound derivative (1.0 equivalent) represented by the structural formula (III):
And a secondary amine compound (2.0 to 2.1 equivalents) represented by the following formula: 4.0 to 8.0 equivalents of copper powder, 8.0 to 12.0 equivalents of carbonate base, 0.2 A method for producing a triarylamine dimer compound according to claim 8, wherein ˜0.8 equivalent of crown ether is added and reacted to obtain the triarylamine dimer compound according to claim 8.