JP4793218B2 - Electrophotographic photoreceptor and image forming apparatus using the photoreceptor - Google Patents

Description

  The present invention relates to an electrophotographic photoreceptor using a novel hydrazone compound and an image forming apparatus using the electrophotographic photoreceptor.

  The electrophotographic technique is widely used in the fields of copiers, various printers, printing machines, etc. because it is excellent in immediacy and provides high-quality images. As an electrophotographic photoreceptor (hereinafter also simply referred to as “photoreceptor”), which is the core of electrophotographic technology, it has advantages such as non-pollution, easy film formation, and easy manufacture. An electrophotographic photoreceptor using a photoconductive material is mainly used.

  As an electrophotographic photosensitive member using an organic photoconductive material, a so-called dispersion type single layer type photosensitive member in which a photoconductive fine powder is dispersed in a binder resin, a charge generation layer and a charge transport layer are laminated. A laminated type photoconductor is known. Multilayer photoconductors can provide highly sensitive and stable photoconductors by combining high-efficiency charge generation materials and charge transport materials into separate layers, and combining them with optimal materials. Photoconductors that are easy to adjust, can be easily formed by coating, have high productivity, and are advantageous in terms of cost, are the mainstream of photoconductors and are widely used.

  On the other hand, the single-layer type photoconductor is slightly inferior to the multilayer type photoconductor in terms of electrical characteristics and the degree of freedom of material selection is slightly smaller, but it can generate charges near the photoconductor surface, so it has higher resolution. In addition, there is an advantage that high printing durability can be achieved by increasing the thickness of the film because the image is not blurred even if the photosensitive layer is thick. In addition, the single-layer type photoreceptor is advantageous in that there are few coating steps and is advantageous for interference fringes and tube defects derived from a conductive substrate (support), and an inexpensive substrate such as a non-cutting tube can be used. For these reasons, there is an advantage that the cost can be reduced.

  Since these electrophotographic photoreceptors are repeatedly used in an electrophotographic process, that is, a cycle such as charging, exposure, development, transfer, cleaning, and charge removal, they are deteriorated by various stresses. One of the main causes of deterioration is that strong oxidizing ozone or NOx generated from a corona charger normally used as a charger damages the photosensitive layer. When the photoreceptor is used repeatedly, This is a factor that causes a decrease in electrical stability such as a decrease in chargeability and an increase in residual potential, and a resulting image defect. This is largely due to chemical degradation of the charge transport material contained in the photosensitive layer. Therefore, there is a need for a charge transport material that is less chemically degraded, that is, excellent in oxidation resistance.

  In addition, with the recent increase in the speed of the electrophotographic process, it is essential to increase the sensitivity and speed of the electrophotographic photosensitive member. Of these, in order to achieve high sensitivity, it is necessary not only to optimize charge generation materials, but also to develop charge transport materials with good matching with them. There is a need to develop charge transport materials that are sensitive and that exhibit a sufficiently low residual potential upon exposure.

  Conventionally, hydrazone compounds have been known as charge transport materials. For example, Patent Document 1 proposes the use of a hydrazone compound group having a specific structure as a charge transport material for an electrophotographic photoreceptor. .

Patent Document 2 discloses that a monohydrazone compound having a tetraphenylbenzidine skeleton can be used as a charge transport material.
Japanese Patent No. 2644925 Japanese Patent No. 3013474

  Among the hydrazone compound group described in Patent Document 1, a compound having a triarylamine skeleton exhibits relatively excellent characteristics in terms of photosensitivity and residual potential during exposure. However, it has the disadvantages that it is very easily oxidized and has a low charge mobility. Therefore, the electrophotographic photosensitive member using this as a charge transporting material not only has insufficient responsiveness, but also when used repeatedly, due to an oxidizing gas such as ozone, the charging property decreases and the residual potential. As a result, there has been a problem that the electrical characteristics are reduced, such as an increase in the temperature.

  In addition, the compound group described in Patent Document 2 has a problem that the sensitivity and residual potential are relatively good, while the charge mobility is slow, and is not necessarily suitable as a charge transport material for an electrophotographic photosensitive member. Therefore, the fact is that these charge transport materials are not yet satisfied in the photoreceptor market.

  The present invention has been made in view of the current situation, and the object thereof is an electrophotographic photosensitive member having a photosensitive layer having excellent oxidation resistance, high charge mobility, and excellent electrical properties, And providing an image forming apparatus using the photosensitive member.

  As a result of intensive studies on the charge transport material, the present inventors have found that a specific hydrazone derivative having a triarylamine skeleton is an excellent charge transport material that can solve the above problems, and to complete the present invention. It came.

  That is, according to the first aspect of the present invention, in an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer contains at least one hydrazone compound represented by the following formula [I]. An electrophotographic photosensitive member characterized by the above is provided to solve the above problems.

（式［Ｉ］中、Ａｒ^１〜Ａｒ^５は、それぞれ独立に、置換基を有していてもよいアリール基を示す。ただし、Ａｒ ^４ またはＡｒ ^５ のいずれかが、上記式［ＩＩ］で表される置換基を有する場合を除く。Ａは、アルケニレン基またはアリーレン基を示し、Ｙ^１〜Ｙ^３は、それぞれ独立に、水素原子または一価の置換基を示す。ただし、Ｙ^１〜Ｙ^３は、水酸基であってはならない。）

(Wherein ^[I], Ar 1 ~Ar ⁵ each independently shows the aryl group which may have a substituent. However, either Ar ⁴ or Ar ⁵ has the formula [II] in unless having a substituent represented. a represents an alkenylene group or an arylene group, Y ¹ to Y ³ each independently represent a hydrogen atom or a monovalent substituent. However, Y ¹ ~ Y ³ must not be a hydroxyl group.)

  According to a second aspect of the present invention, there is provided an electrophotographic photosensitive member, a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, and exposure. 2. An image forming apparatus comprising: a developing unit that develops an electrostatic latent image formed on the electrophotographic photosensitive member using toner with the electrophotographic photosensitive member according to claim 1. It is an object of the present invention to provide an image forming apparatus that is a photoconductor to solve the above problems.

  The hydrazone compound having a triarylamine skeleton represented by the formula [I] contained in the photosensitive layer of the electrophotographic photoreceptor according to the present invention has excellent oxidation resistance, high charge mobility, and excellent electrical properties. Has characteristics. Therefore, the electrophotographic photosensitive member and the image forming apparatus according to the present invention have stable electrical characteristics, fast response, high sensitivity, and low residual potential even when used repeatedly.

  Such an operation and a gain of the present invention will be clarified from the best mode for carrying out the invention described below.

  The electrophotographic photoreceptor of the present invention is characterized in that the photosensitive layer contains a hydrazone compound having a triarylamine skeleton represented by the following formula [I].

In formula [I], Ar < ¹ > -Ar < ⁵ > shows the aryl group which may have a substituent each independently. Ar ^{1 to} Ar ⁵ are preferably aryl groups having 6 to 20 carbon atoms, which may be the same or different. Specific examples of the aryl group include a phenyl group, a naphthyl group, a fluorenyl group, an anthryl group, a phenanthryl group, and a pyrenyl group. From the viewpoint of production cost, an aryl group having 6 to 15 carbon atoms such as phenyl group and anthryl group is preferable, and an aryl group having 6 to 10 carbon atoms such as phenyl group and naphthyl group is particularly preferable. Further, when it has a substituent, the substituent usually has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms. It is what has. In general, a substituent having a substituent constant σ _p in the Hammett rule of 0.20 or less, preferably 0 or less, particularly preferably −0.10 or less. In particular, it is preferable that the number of carbon atoms is in the specific range and the substituent constant σ _p is also in the specific range.

Here, the Hammett's rule is an empirical rule used to explain the effect of a substituent in an aromatic compound on the electronic state of the aromatic ring. The substituent constant σ _p of the substituted benzene is an index representing the degree of electron donation / attraction of the substituent, and the larger the σ _p value of the substituent in the positive direction, the stronger the electron withdrawing property. Conversely, the larger the σ _p value of the substituent in the negative direction, the stronger the electron donating property. Table 1 shows σ _p values of typical substituents (The Chemical Society of Japan, “Chemical Handbook, Basic Edition II, 4th revised edition”, Maruzen Co., Ltd., published on September 30, 1993, p.364-365). ).

  Preferred examples of the substituent include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkylamino group having 2 to 4 carbon atoms, and an aryl group having 6 to 10 carbon atoms. Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, methoxy group, ethoxy group, propoxy group, butoxy group, N, N-dimethylamino Group, N, N-diethylamino group, phenyl group, 4-tolyl group, 4-ethylphenyl group, 4-propylphenyl group, 4-butylphenyl group, naphthyl group and the like. Among these, an alkyl group having 1 to 4 carbon atoms is particularly preferable from the viewpoint of electrical characteristics of the electrophotographic photosensitive member.

In formula [I], Y < ¹ > -Y < ³ > is a substituent which exists in the arbitrary positions on each benzene ring, and shows a hydrogen atom or a monovalent substituent each independently. However, Y ^{1 to} Y ³ must not be a hydroxyl group.

Hydroxyl groups are known to have strong electron donating properties and strong polarity. For this reason, the ionization potential of the whole molecule tends to be lowered, which not only makes it difficult to withstand oxidation, but also causes a bias in the charge distribution of the molecule and lowers the charge mobility. Therefore, in the present invention, in order to ensure the oxidation resistance and high charge mobility of the compound represented by the formula [I], the hydroxyl group is removed from the substituents represented by Y ¹ to Y ³ .

Examples of the monovalent substituent represented by Y ^{1 to} Y ³ include a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkylamino group having 2 to 4 carbon atoms, and 6 carbon atoms. To 10 aryl groups, specifically, fluorine, chlorine, bromine, iodine, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group , Methoxy group, ethoxy group, propoxy group, butoxy group, N, N-dimethylamino group, N, N-diethylamino group, phenyl group, 4-tolyl group, 4-ethylphenyl group, 4-propylphenyl group, 4- A butylphenyl group, a naphthyl group, etc. are mentioned. From the viewpoint of easier production, Y ^{1 to} Y ³ are particularly preferably hydrogen atoms.

In the formula [I], A represents an alkenylene group or an arylene group bonded to two benzene rings at respective arbitrary positions. As the alkenylene group, those having 2 to 14 carbon atoms are preferable, and as the arylene group, those having 6 to 20 carbon atoms are preferable. Specific examples include an ethylenylene group, a methyl ethylenylene group, a phenyl ethylenylene group, a phenylene group, a naphthylene group, an anthrylene group, a phenanthrylene group, a pyrenylene group, and a biphenylene group. From the viewpoint of electrical characteristics of the electrophotographic photoreceptor, an ethylenylene group and a phenylene group are particularly preferable. In addition, when these groups further have a substituent, the substituent is preferably a group having 1 to 10 carbon atoms, and in particular, a substituent having a substituent constant σ _p in the Hammett rule of 0.20 or less. Particularly preferred. Examples of such a substituent include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkylamino group having 2 to 4 carbon atoms, and an aryl group having 6 to 10 carbon atoms. Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, tert-butyl group, methoxy group, ethoxy group, propoxy group, butoxy group, N, N- Examples include dimethylamino group, N, N-diethylamino group, phenyl group, 4-tolyl group, 4-ethylphenyl group, 4-propylphenyl group, 4-butylphenyl group, and naphthyl group. From the viewpoint of production cost, A is preferably unsubstituted.

  As specific examples of the hydrazone compound represented by the formula [I] used in the present invention, typical compounds CT-1 to CT-11 are shown below. However, the hydrazone compound represented by the formula [I] is not limited to these compounds.

  These hydrazone compounds can be easily synthesized by known methods. For example, exemplary compound CT-1 of this invention can be manufactured according to the following reaction formula.

  First, a formyl form (B) obtained by formylating a triarylamine (A) by a Vilsmeier reaction and a phosphate ester (D) obtained by reacting p-bromobenzyl bromide (C) with triethyl phosphite. By condensing in the presence of a base, a stilbene derivative (E) having a triarylamine skeleton is obtained. Subsequently, stilbene derivative (F) is obtained by coupling (E) with diarylamine. Thereafter, (F) is formylated again by the Vilsmeier reaction to form a formyl form (G), and finally, N, N-diarylhydrazine is dehydrated and condensed under acidic conditions to obtain the target hydrazone compound. Can do.

  The electrophotographic photosensitive member of the present invention has a particularly specific structure as long as the photosensitive layer containing the hydrazone compound having the above-described triarylamine skeleton represented by the formula [I] is provided on a conductive support. Not limited. Hereinafter, a specific configuration example of the electrophotographic photosensitive member according to the present invention and an image forming apparatus using the same will be described in detail.

1. Electrophotographic photoreceptor <Conductive support>
There is no particular limitation on the conductive support, but for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper, and nickel, and conductive powders such as metal, carbon, and tin oxide are added to impart conductivity. A resin material, a resin, glass, paper, or the like in which a conductive material such as aluminum, nickel, or ITO (indium tin oxide) is deposited or applied on the surface is mainly used. These may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and ratios. As a form of the conductive support, a drum form, a sheet form, a belt form or the like is used. Furthermore, a conductive material having an appropriate resistance value may be used on a conductive support made of a metal material in order to control conductivity and surface properties and to cover defects.

  Moreover, when using metal materials, such as an aluminum alloy, as an electroconductive support body, you may use, after giving an anodic oxide film. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method.

  The support surface may be smooth, or may be roughened by using a special cutting method or performing a polishing treatment. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. In order to reduce the cost, it is possible to use the drawing tube as it is without performing the cutting process.

<Underlayer>
An undercoat layer may be provided between the conductive support and the photosensitive layer described later for improving adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable. The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicon. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of the several crystal state may be contained.

  In addition, various particle diameters of metal oxide particles can be used. Among these, from the viewpoint of characteristics and liquid stability, the average value of the maximum diameters of any 10 particles observed by SEM photographs is averaged. The primary particle size is preferably 10 nm or more and 100 nm or less, and particularly preferably 10 nm or more and 50 nm or less.

  The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. As binder resin used for the undercoat layer, epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, Polyimide resin, vinylidene chloride resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacrylic acid resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester resin, nitro Cellulose ester resins such as cellulose, cellulose ether resins, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate Compounds, organic zirconium compounds such as zirconium alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanyl alkoxide compound, a known binder resin such as a silane coupling agent and the like. These may be used alone or in combination of two or more in any combination and ratio. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamides, modified polyamides, and the like are preferable because they exhibit good dispersibility and coatability.

  The use ratio of the inorganic particles to the binder resin used in the undercoat layer can be arbitrarily selected, but is usually in the range of 10% by mass or more and 500% by mass or less from the viewpoint of the stability of the dispersion and coating properties. Is preferably used.

  The thickness of the undercoat layer can be selected arbitrarily, but is usually preferably in the range of 0.1 μm or more and 20 μm or less from the viewpoint of improving the photoreceptor characteristics and coating properties.

  Further, the undercoat layer may be mixed with a known antioxidant or the like, and may contain pigment particles, resin particles, etc. for the purpose of preventing image defects.

<Photosensitive layer>
As the type of the photosensitive layer of the electrophotographic photosensitive member, the charge generation material and the charge transport material are present in the same layer, and the single layer type dispersed in the binder resin, and the charge generation material is dispersed in the binder resin. A functional separation type (laminated type) composed of two layers of a charge generation layer and a charge transport layer in which a charge transport material is dispersed in a binder resin can be mentioned. In the present invention, any type can be used.

  In addition, as the laminated photosensitive layer, a charge generation layer and a charge transport layer are laminated in this order from the conductive support side, and a charge transport layer and a charge generation layer are laminated in this order. Although there is a reverse laminated type photosensitive layer, any of them can be adopted.

  As the photosensitive layer in the present invention, a laminated photosensitive layer in which a charge generation layer and a charge transport layer are laminated is preferable, and in particular, the charge transport layer contains a hydrazone compound represented by the formula [I]. Is preferred. Further, among the laminated type photosensitive layers, a forward laminated type photosensitive layer capable of exhibiting balanced photoconductivity is particularly preferable.

(Laminated photosensitive layer)
-Charge generation layer In the case of a laminated photosensitive layer (function-separated type photoreceptor), the charge generation layer is formed by binding a charge generation material with a binder resin. Examples of the charge generation material include inorganic photoconductive materials such as selenium and its alloys, cadmium sulfide, and organic photoconductive materials such as organic pigments, but organic photoconductive materials are preferred, especially organic pigments. Is preferred. Examples of organic pigments include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments. . Among these, phthalocyanine pigments or azo pigments are particularly preferable. When organic pigments are used as the charge generating substance, usually, fine particles of these organic pigments are used in the form of a dispersion layer bound with various binder resins.

  When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as the charge generation material, a photosensitive member having a high sensitivity to a laser beam having a relatively long wavelength, for example, a laser beam having a wavelength around 780 nm, is obtained. When azo pigments such as diazo and trisazo are used, white light, laser light having a wavelength around 660 nm, or relatively short wavelength laser light (for example, laser light having a wavelength in the range of 380 to 500 nm) Thus, a photoreceptor having sufficient sensitivity can be obtained.

  When an organic pigment is used as the charge generating material, a phthalocyanine pigment or an azo pigment is particularly preferable. The phthalocyanine pigment provides a highly sensitive photoconductor with respect to a relatively long wavelength laser beam, and the azo pigment includes white light and a relatively short wavelength laser beam (for example, a wavelength in the range of 380 to 500 nm). Each of them is excellent in that it has sufficient sensitivity to a laser beam.

  When using a phthalocyanine pigment as a charge generation material, specifically, metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum or other metal or oxide thereof, halide, water Those having crystal forms of coordinated phthalocyanines such as oxides and alkoxides, and phthalocyanine dimers using oxygen atoms as bridging atoms are used. Particularly, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystal types Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, hydroxyindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and type I, type II, etc. The [mu] -oxo-aluminum phthalocyanine dimer is preferred.

  Among these phthalocyanines, A-type (also known as β-type), B-type (also known as α-type), and powder X-ray diffraction angle 2θ (± 0.2 °) are 27.1 ° or 27.3 °. D-type (Y-type) titanyl phthalocyanine, II-type chlorogallium phthalocyanine, V-type and 28.1 ° have the strongest peaks, and 26.2 ° have peaks Hydroxygallium phthalocyanine having a clear peak at 28.1 ° and a full width at half maximum W of 25.9 ° of 0.1 ° ≦ W ≦ 0.4 °, G-type μ-oxo -Gallium phthalocyanine dimer and the like are particularly preferable.

  As the phthalocyanine compound, a single compound may be used, or several mixed or mixed crystals may be used. As the mixed state in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or the mixed state in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, crystallization, etc. It may be the one that gave rise to. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, two types of crystals are mixed, mechanically ground and made amorphous, and then converted into a specific crystal state by solvent treatment. The method of doing is mentioned.

  When an azo pigment is used as the charge generation material, various bisazo pigments and trisazo pigments are preferably used. Examples of preferred azo pigments are shown below.

  When the organic pigments exemplified above are used as the charge generation material, one kind may be used alone, or two or more kinds of pigments may be mixed and used. In this case, it is preferable to use a combination of two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near red region. Among them, a disazo pigment, a trisazo pigment and a phthalocyanine pigment are preferably used in combination. More preferred.

  The binder resin used for the charge generation layer is not particularly limited, but examples include polyvinyl butyral resin, polyvinyl formal resin, polyvinyl acetal type such as partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal, acetal, or the like. Resin, Polyarylate resin, Polycarbonate resin, Polyester resin, Modified ether type polyester resin, Phenoxy resin, Polyvinyl chloride resin, Polyvinylidene chloride resin, Polyvinyl acetate resin, Polystyrene resin, Acrylic resin, Methacrylic resin, Polyacrylamide resin, Polyamide Resin, polyvinyl pyridine resin, cellulose resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, vinyl chloride -Vinyl acetate-vinyl acetate copolymers such as vinyl acetate copolymers, hydroxy-modified vinyl chloride-vinyl acetate copolymers, carboxyl-modified vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, etc. Insulating resins such as polymers, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, styrene-alkyd resins, silicon-alkyd resins, phenol-formaldehyde resins, poly-N-vinylcarbazole, polyvinyl anthracene, polyvinyl And organic photoconductive polymers such as perylene. Any one of these binder resins may be used alone, or two or more thereof may be mixed and used in any combination.

  The charge generation layer is prepared by dispersing a charge generation material in a solution obtained by dissolving the above-described binder resin in an organic solvent and preparing a coating solution on the conductive support (if an undercoat layer is provided, an undercoat layer). It is formed by coating.

  The solvent used for preparing the coating solution is not particularly limited as long as it dissolves the binder resin. For example, saturated aliphatic solvents such as pentane, hexane, octane, and nonane, and aromatics such as toluene, xylene, and anisole. Group solvents, halogenated aromatic solvents such as chlorobenzene, dichlorobenzene, chloronaphthalene, amide solvents such as dimethylformamide, N-methyl-2-pyrrolidone, methanol, ethanol, isopropanol, n-butanol, benzyl alcohol, etc. Alcohol solvents, aliphatic polyhydric alcohols such as glycerin and polyethylene glycol, chain or cyclic ketone solvents such as acetone, cyclohexanone, methyl ethyl ketone, 4-methoxy-4-methyl-2-pentanone, methyl formate, ethyl acetate, Acetic acid n- Chains such as ester solvents such as chill, halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,2-dichloroethane, diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve, etc. Or cyclic ether solvents, acetonitrile, dimethylsulfoxide, sulfolane, aprotic polar solvents such as hexamethylphosphoric triamide, n-butylamine, isopropanolamine, diethylamine, triethanolamine, ethylenediamine, triethylenediamine, triethylamine and other nitrogen-containing compounds Compound, mineral oil such as ligroin, water and the like. Any one of these may be used alone, or two or more of these may be used in combination. In addition, when providing the above-mentioned undercoat layer, what does not melt | dissolve this undercoat layer is preferable.

  In the charge generation layer, the mixing ratio (mass) of the binder resin and the charge generation material is usually 10 parts by mass or more, preferably 30 parts by mass or more, and usually 1000 parts by mass with respect to 100 parts by mass of the binder resin. Part or less, preferably 500 parts by mass or less, and the film thickness is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 10 μm or less, preferably 0.6 μm or less. If the ratio of the charge generation material is too high, the stability of the coating solution may be reduced due to aggregation of the charge generation material, while if the ratio of the charge generation material is too low, the sensitivity as a photoreceptor may be decreased. There is.

  As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used. At this time, it is effective to reduce the volume average particle size of the particles to a particle size in the range of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

・ Charge transport layer
The charge transport layer of the multilayer photoreceptor contains a charge transport material and usually contains a binder resin and other components used as necessary. Specifically, such a charge transport layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge transport material or the like and a binder resin in a solvent. In addition, in the case of a reverse lamination type photosensitive layer, it can be obtained by coating and drying on a conductive support (or on the undercoat layer when an undercoat layer is provided).

  In the present invention, the hydrazone compound represented by the formula [I] described above is used as the charge transport material. One hydrazone compound may be used alone, or a plurality of hydrazone compounds may be used in any combination and ratio. In addition to the hydrazone compound represented by the formula [I], other known charge transport materials may be used in combination.

  When other charge transport materials are used in combination, the type is not particularly limited, but for example, carbazole derivatives, other hydrazone compounds, aromatic amine derivatives, stilbene derivatives, butadiene derivatives and those in which a plurality of these derivatives are bonded are preferable. More specifically, compounds described in JP-A-2-230255, JP-A-63-225660, JP-A-58-198043, JP-B-58-32372, and JP-B-7-21646 Are preferably used. Any one of these charge transport materials may be used alone, or a plurality of types may be used in any combination. When the hydrazone compound represented by the formula [I] and another known charge transport material are used in combination, the content ratio (% by mass) of the charge transport material to be used in the total amount of the charge transport material is not particularly limited. , Preferably in the range of 1 to 20%. In order to effectively exhibit the performance of the hydrazone compound represented by the formula [I], it is particularly preferably in the range of 3 to 10%.

  Examples of the binder resin used for the charge transport layer include polymers of vinyl compounds such as butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, vinyl alcohol resin, ethyl vinyl ether, and the like. Copolymer, polyvinyl butyral resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyester resin, polyarylate resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicon resin, silicon-alkyd resin, poly- N-vinyl carbazole resin etc. are mentioned. Of these, polycarbonate resins and polyarylate resins are preferred. These binder resins can also be used after being crosslinked by heat, light or the like using an appropriate curing agent. Any one of these binder resins may be used alone, or two or more thereof may be used in any combination.

  The binder resin and the charge transport material are usually mixed at a ratio of 20 parts by mass or more with respect to 100 parts by mass of the binder resin. Among these, 30 parts by mass or more is preferable from the viewpoint of residual potential reduction, and 40 parts by mass or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used at a ratio of 150 parts by mass or less. Among these, 110 parts by mass or less is preferable from the viewpoint of compatibility between the charge transport material and the binder resin, 80 parts by mass or less is more preferable from the viewpoint of printing durability, and 70 parts by mass or less is most preferable from the viewpoint of scratch resistance.

  The thickness of the charge transport layer is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, and usually 50 μm or less, preferably 45 μm or less, from the viewpoint of long life, image stability, and high resolution. Is in the range of 30 μm or less.

(Single layer type photosensitive layer)
The single-layer type photosensitive layer is formed using a binder resin in order to ensure film strength, in the same manner as the charge transport layer of the multilayer photoreceptor, in addition to the charge generation material and the charge transport material. Specifically, a charge generation material, a charge transport material, and various binder resins are dissolved or dispersed in a solvent to prepare a coating solution, and on a conductive support (or an undercoat layer when an undercoat layer is provided). It can be obtained by coating and drying.

  The types of the charge transport material and the binder resin and the use ratios thereof are the same as those described for the charge transport layer of the multilayer photoreceptor. In the single-layer type photosensitive layer, a charge generating material is further dispersed in a charge transport medium comprising these charge transport material and binder resin.

  As the charge generation material, the same materials as those described for the charge generation layer of the multilayer photoreceptor can be used. However, in the case of a photosensitive layer of a single-layer type photoreceptor, it is necessary to sufficiently reduce the particle size of the charge generating material. Specifically, the range is usually 1 μm or less, preferably 0.5 μm or less.

  If the amount of the charge generating material dispersed in the single-layer type photosensitive layer is too small, sufficient sensitivity cannot be obtained, but if it is too large, there are adverse effects such as a decrease in chargeability and a decrease in sensitivity. It is used in the range of usually 0.5% by mass or more, preferably 1% by mass or more, and usually 50% by mass or less, preferably 20% by mass or less based on the whole layer-type photosensitive layer.

  In addition, the usage ratio of the binder resin and the charge generation material in the single-layer type photosensitive layer is such that the charge generation material is usually 0.1 parts by weight or more, preferably 1 part by weight or more, based on 100 parts by weight of the binder resin. It is 30 mass parts or less, Preferably it is set as the range of 10 mass parts or less.

  The film thickness of the single-layer type photosensitive layer is usually 5 μm or more, preferably 10 μm or more, and usually 100 μm or less, preferably 50 μm or less.

  In addition, both the layered type photosensitive member and the single layer type photosensitive member improve the film forming property, flexibility, coating property, contamination resistance, gas resistance, light resistance, etc. in the photosensitive layer or each layer constituting the photosensitive layer. For the purpose, additives such as known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds, leveling agents, and visible light shielding agents may be contained.

(Other functional layers)
In both the multilayer type photoreceptor and the single-layer type photoreceptor, the photosensitive layer formed by the above procedure may be used as the uppermost layer, that is, the surface layer, but another layer may be provided thereon, and this may be used as the surface layer.

  For example, a protective layer may be provided for the purpose of preventing wear of the photosensitive layer or preventing or reducing deterioration of the photosensitive layer due to discharge products generated from a charger or the like.

  The protective layer is formed by containing a conductive material in a suitable binder resin, or a copolymer using a compound having charge transporting ability such as a triphenylamine skeleton described in JP-A-9-190004. Can be used.

  Examples of the conductive material used for the protective layer include aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, and oxide. Metal oxides such as titanium, tin oxide-antimony oxide, aluminum oxide, and zinc oxide can be used, but are not limited thereto.

  As the binder resin used for the protective layer, known resins such as polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, and siloxane resin can be used. Also, a copolymer of the above resin with a skeleton having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 can be used.

The electrical resistance of the protective layer is usually in the range of 10 ⁹ Ω · cm to 10 ¹⁴ Ω · cm. If the electric resistance is higher than the above range, the residual potential is increased, resulting in an image with much fog. On the other hand, if the electric resistance is lower than the above range, the image is blurred and the resolution is reduced. Further, the protective layer must be configured so as not to substantially prevent transmission of light irradiated during image exposure.

  In addition, for the purpose of reducing the frictional resistance and wear on the surface of the photoconductor, and increasing the transfer efficiency of the toner from the photoconductor to the transfer belt, paper, etc. Particles made of the above resin or inorganic compound particles may be contained in the surface layer. Alternatively, a layer containing these resins and particles may be newly formed as a surface layer.

<Method for forming electrophotographic photoreceptor>
Each of the above-described layers constituting the photoreceptor is formed by laminating a coating solution obtained by dissolving or dispersing a substance to be contained in a solvent by sequentially repeating coating and drying steps using a known technique. .

  There are no particular restrictions on the solvent or dispersion medium used for the preparation of the coating solution, but specific examples include alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, tetrahydrofuran, 1,4-dioxane, dimethoxyethane and the like. Ethers, esters such as methyl formate and ethyl acetate, acetone, methyl ethyl ketone, cyclohexanone, ketones such as 4-methoxy-4-methyl-2-pentanone, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, Chlorinated hydrocarbons such as chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichloroethylene, n-butylamine, isopropanolamine, Diethyl Min, triethanolamine, ethylenediamine, nitrogen-containing compounds such as triethylenediamine, acetonitrile, N- methylpyrrolidone, N, N- dimethylformamide, aprotic polar solvents such as dimethyl sulfoxide and the like. Moreover, these may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and kinds.

  The amount of the solvent or the dispersion medium used is not particularly limited, but considering the purpose of each layer and the properties of the selected solvent / dispersion medium, it is appropriately determined so that the physical properties such as the solid content concentration and viscosity of the coating liquid are within a desired range. It is preferable to adjust.

  For example, in the case of a charge transport layer of a single layer type photoreceptor or a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, usually 5% by mass or more, preferably 10% by mass or more. The range is usually 40% by mass or less, preferably 35% by mass or less. Further, the viscosity of the coating solution is usually 10 mPa · s or higher, preferably 50 mPa · s or higher, and usually 500 mPa · s or lower, preferably 400 mPa · s or lower.

  In the case of a charge generation layer of a multilayer photoreceptor, the solid content concentration of the coating solution is usually 0.1% by mass or more, preferably 1% by mass or more, and usually 15% by mass or less, preferably 10% by mass. % Or less. Further, the viscosity of the coating solution is usually 0.01 mPa · s or more, preferably 0.1 mPa · s or more, and usually 20 mPa · s or less, preferably 10 mPa · s or less.

  Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, and a curtain coating method. Other known coating methods can also be used.

  The coating solution is preferably dried by touching at room temperature, followed by heating and drying in a temperature range of usually 30 ° C. or higher and 200 ° C. or lower for 1 minute to 2 hours, either statically or under ventilation. Further, the heating temperature may be constant, or heating may be performed while changing the temperature during drying.

2. Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention (an image forming apparatus of the present invention) will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.

  As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further, a transfer device 5, a cleaning device 6 and a fixing device as necessary. A device 7 is provided.

  The electrophotographic photosensitive member 1 is not particularly limited as long as it is the above-described electrophotographic photosensitive member of the present invention, but in FIG. 1, as an example, a drum-like shape in which a photosensitive layer is formed on the surface of a cylindrical conductive support. The photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photoreceptor 1.

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. Examples of the charging device include a corona charging device such as a corotron and a scorotron, a direct charging device (contact type charging device) that charges a direct charging member to which a voltage is applied by contacting the photosensitive member surface, and a contact type charging device such as a charging brush. Often used. Examples of direct charging means include contact chargers such as charging rollers and charging brushes. In FIG. 1, a roller-type charging device (charging roller) is shown as an example of the charging device 2. As the direct charging means, either charging with air discharge or injection charging without air discharge is possible. In addition, as a voltage applied at the time of charging, in the case of only a direct current voltage, an alternating current can be superimposed on a direct current.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light having a wavelength of 780 nm, monochromatic light having a wavelength of 600 nm to 700 nm, slightly short wavelength, or monochromatic light having a wavelength of 380 nm to 500 nm. .

  The type of the developing device 4 is not particularly limited, and an arbitrary device such as a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, or two-component magnetic brush development, or a wet development method is used. be able to. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and is configured to store toner T inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. The replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

  The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicon resin, a urethane resin, a fluororesin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.

  The developing roller 44 is disposed between the electrophotographic photosensitive member 1 and the supply roller 43 and is in contact with the electrophotographic photosensitive member 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The regulating member 45 is formed of a resin blade such as silicon resin or urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating such a metal blade with resin. The regulating member 45 contacts the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

  The agitator 42 is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like disposed so as to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a recording paper (paper, medium) P. Is.

  There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner. However, when there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning device 6 may not be provided.

  The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. As the upper and lower fixing members 71 and 72, known heat fixing members such as a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll coated with a fluororesin, or a fixing sheet are used. be able to. Further, the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve the releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

  When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P.

  The type of the fixing device is not particularly limited, and a fixing device of any type such as heat roller fixing, flash fixing, oven fixing, pressure fixing, etc. can be provided including those used here.

  In the electrophotographic apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed with a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.

  Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1.

  The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.

  When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.

  After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P.

  In addition to the above-described configuration, the image forming apparatus may be configured to perform, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

  Further, the image forming apparatus may be further modified and configured, for example, a configuration capable of performing processes such as a pre-exposure process and an auxiliary charging process, a structure performing offset printing, and a plurality of types. A full-color tandem system configuration using toner may be used.

  The electrophotographic photosensitive member 1 is combined with one or more of the charging device 2, the exposure device 3, the developing device 4, the transfer device 5, the cleaning device 6, and the fixing device 7 to form an integrated cartridge ( The electrophotographic photosensitive member cartridge may be configured to be detachable from a main body of an electrophotographic apparatus such as a copying machine or a laser beam printer. In this case, for example, when the electrophotographic photosensitive member 1 and other members are deteriorated, the electrophotographic photosensitive member cartridge is removed from the main body of the image forming apparatus, and another new electrophotographic photosensitive member cartridge is mounted on the main body of the image forming apparatus. This facilitates maintenance and management of the image forming apparatus.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In addition, the following examples are shown in order to explain the present invention in detail, and the present invention is not limited to the following examples unless it is contrary to the gist thereof.

1. Synthesis of hydrazone compound (Production Example 1: Synthesis of exemplary compound CT-1)
Under a nitrogen atmosphere, 10.94 g (40 mmol) of N, N-di (p-tolyl) aniline (A) was dissolved in 50 ml of dimethylformamide (hereinafter referred to as DMF) with mechanical stirring. To this, 7.97 g (52 mmol) of phosphorus oxychloride (POCl ₃ ) was slowly dropped while maintaining a temperature of 65 to 70 ° C., and further stirred at the same temperature for 6 hours. After cooling to room temperature, the reaction solution and toluene / demineralized water (v / v = 1: 1) were mixed and stirred for 1 to 2 hours and separated. The aqueous layer was further extracted with toluene, and the obtained organic layer was mixed with the organic layer obtained by liquid separation earlier. This organic layer was washed with 1N NaOH aqueous solution and separated, and the organic layer was further washed with demineralized water 2-3 times and separated. The solvent of the obtained organic layer was distilled off under reduced pressure, and further dried under reduced pressure at 60 ° C. to obtain 10.55 g (35 mmol, yield 87%) of formyl form (B).

  Under a nitrogen atmosphere, 39.88 g (0.24 mol) of triethyl phosphite was added to 49.99 g (0.2 mol) of p-bromobenzyl bromide (C), and the mixture was stirred at 90 ° C. for 1 hour. After distilling off excess triethyl phosphite by distillation under reduced pressure, 61.55 g (197 mmol, yield 98.5%) of the phosphate ester (D) was obtained by cooling to room temperature.

  In a nitrogen atmosphere, 10.55 g (35 mmol) of the formyl body (B) synthesized above and 11.83 g (38.5 mmol) of the phosphate ester body (D) were dissolved in 100 ml of DMF, and the mixture was stirred at room temperature. Potassium tert-butoxide 4.71 g (42 mmol) was slowly added (cooled if necessary) and stirred for an additional hour. This solution was dropped into 300 ml of methanol and crystallized. The solid was filtered off and dried under reduced pressure at 50 ° C. to obtain 14.31 g (31.5 mmol, yield 90%) of a stilbene derivative (E) as a yellow powder.

  In a 300 ml four-necked flask equipped with a stirrer, a thermometer, and a reflux tube under a nitrogen atmosphere, 14.31 g (31.5 mmol) of the stilbene derivative (E) and 6.35 g (34. 7 mmol), 3.34 g (34.8 mmol) of sodium tert-butoxide, and 100 ml of sufficiently deoxygenated xylene, and the system was purged with nitrogen. Then, 5.6 mg of palladium acetate, 15% toluene of tricyclohexylphosphine 234 mg of the solution was added, the mixture was heated to 140 ° C., and the reaction was continued while heating to reflux while maintaining the temperature. During the reaction, the reaction system solution is monitored by high performance liquid chromatography (column: Inert Sil ODS-3V manufactured by GL Sciences Inc., solvent: acetonitrile) at regular intervals, and the reaction system solution The reaction was continued until the stilbene derivative (E) disappeared (about 3 hours). After completion of the reaction, the reaction mixture was cooled to room temperature, the solid was filtered off, and the filtrate was concentrated under reduced pressure. The obtained oil was passed through flash column chromatography (silica gel 500 g, developing solvent: toluene / hexane = 1/2), and further purified by reprecipitation with methanol. This was vacuum-dried to obtain 14.73 g (26.5 mmol, 84% yield) of a stilbene derivative (F) as a yellow powder.

Under a nitrogen atmosphere, 14.73 g (26.5 mmol) of the stilbene derivative (F) was dissolved in 70 ml of DMF with mechanical stirring. Thereafter, while heating to 65 ° C. and maintaining the same temperature, 4.74 g (30.9 mmol) of phosphorus oxychloride (POCl ₃ ) was slowly added dropwise, and the mixture was further stirred at the same temperature for 3 hours and cooled to room temperature. Toluene / demineralized water (v / v = 1: 1) was added and stirred sufficiently, followed by liquid separation. The aqueous layer was further stirred with toluene added and separated. The organic layers were combined, washed with 1N NaOH aqueous solution and separated, and the organic layer was further washed with demineralized water 2-3 times and separated. The solvent of the organic layer was distilled off under reduced pressure, and an appropriate amount of toluene was added again to make a solution, which was passed through column chromatography (silica gel 500 g, developing solvent: toluene) and concentrated under reduced pressure. The obtained solid was purified by recrystallization to obtain 5.27 g (9.00 mmol, yield 34%) of a formyl derivative (G) as a yellow powder.

  Under a nitrogen atmosphere, 2.63 g (13.8 mmol) of N-nitrosodiphenylamine, 2.04 g (31.3 mmol) of zinc powder, and 25 ml of methanol were charged into the reactor, and 3.7 ml of acetic acid was slowly added while stirring at room temperature. Added dropwise (cooled if necessary). After about 2 hours, the reaction mixture was separated by suction filtration, and the filtrate was added dropwise to a THF solution (while heating under reflux) containing 5.27 g (9.00 mmol) of the formyl derivative (G). The heating reflux was continued for about 1 hour, and then the mixture was cooled to room temperature. THF was added to the reaction mixture and stirred until completely dissolved. This solution was dropped into methanol and crystallized. The obtained crystals were filtered off with suction and dried under reduced pressure at 50 ° C. The crystals were dissolved in a mixed solution of toluene / hexane (v / v = 1/2), passed through column chromatography (silica gel 500 g, developing solvent: toluene / hexane = 1/2), and concentrated under reduced pressure. By refine | purifying the obtained solid by recrystallization, 6.02 g (8.01 mmol, yield 89%) of exemplary compound CT-1 was obtained as yellow powder. The IR spectrum (FT / IR-350 spectrometer manufactured by JASCO) of this compound is shown in FIG.

(Production Example 2: Synthesis of Exemplified Compound CT-7)
The synthesis | combination of exemplary compound CT-7 was performed according to the following scheme.

  In a 500 ml four-necked flask equipped with a stirrer, a thermometer, and a reflux tube under a nitrogen atmosphere, 45.81 g (0.2 mol) of 2- (3-bromophenyl) -1,3-dioxolane, p-ditolylamine 40 .44 g (0.205 mol), sodium tert-butoxide 23.06 g (0.24 mol), and 250 ml of fully deoxygenated xylene were sequentially added, and the inside of the system was replaced with nitrogen, followed by 12 mg of palladium acetate, tricyclohexylphosphine 470 mg of a 15% toluene solution was added, heated to 140 ° C., and kept refluxing while maintaining the temperature, and reacted for about 3 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, the solid was filtered off, and the filtrate was concentrated under reduced pressure. The obtained oil was dissolved in 250 ml of tetrahydrofuran, 10 ml of 10% dilute hydrochloric acid was added, and the mixture was refluxed with heating for about 1 hour. After cooling to room temperature, tetrahydrofuran was distilled off under reduced pressure, and the solid was purified by reprecipitation with methanol. This was vacuum-dried to obtain 49.43 g (164 mmol, yield 82%) of formyl form (B-7).

  Under nitrogen atmosphere, 10.55 g (35 mmol) of the synthesized formyl body (B-7) and 11.83 g (38.5 mmol) of the phosphate ester body (D) obtained in Production Example 1 were dissolved in 100 ml of DMF, In the same manner as in Production Example 1, 14.63 g (32.2 mmol, yield 92%) of a stilbene derivative (E-7) was obtained as a yellow powder.

  In a 300 ml four-necked flask equipped with a stirrer, a thermometer, and a reflux tube under a nitrogen atmosphere, 14.31 g (31.5 mmol) of the stilbene derivative (E-7) and 6.35 g of (p-tolyl) phenylamine were added. (34.7 mmol), 3.34 g (34.8 mmol) of sodium tert-butoxide and 100 ml of sufficiently deoxygenated xylene were added in this order, and the reaction and post-treatment were performed in the same manner as in Production Example 1 to obtain the stilbene derivative (F-7 ) 15.61 g (28.1 mmol, 89% yield) was obtained as a yellow powder.

Under a nitrogen atmosphere, 15.57 g (28.0 mmol) of the stilbene derivative (F-7) was dissolved in 70 ml of DMF with mechanical stirring. Thereafter, while heating to 65 ° C. and maintaining the same temperature, 5.01 g (32.7 mmol) of phosphorus oxychloride (POCl ₃ ) was slowly added dropwise, and the mixture was further stirred at the same temperature for 3 hours and cooled to room temperature. Post-treatment was performed in the same manner as in Production Example 1 to obtain 3.77 g (6.44 mmol, yield 23%) of a formyl derivative (G-7) as a yellow powder.

  Under a nitrogen atmosphere, 1.89 g (9.87 mmol) of N-nitrosodiphenylamine, 1.46 g (22.4 mmol) of zinc powder and 20 ml of methanol were charged into the reactor, and 2.7 ml of acetic acid was slowly added while stirring at room temperature. Added dropwise (cooled if necessary). After about 2 hours, the reaction mixture was separated by suction filtration, and the filtrate was added dropwise to a THF solution (with heating under reflux) containing 3.77 g (6.44 mmol) of the formyl derivative (G-7). Reaction and post-treatment were performed in the same manner as in Production Example 1 to obtain 4.35 g (5.80 mmol, yield 90%) of Exemplary Compound CT-7 as a yellow powder. FIG. 3 shows the IR spectrum (FT / IR-350 spectrometer manufactured by JASCO) of this compound.

(Production Example 3: Synthesis of Exemplified Compound CT-8)
Synthesis of Exemplified Compound CT-8 was performed according to the following scheme.

  Under a nitrogen atmosphere, 39.88 g (0.24 mol) of triethyl phosphite was added to 50.00 g (0.2 mol) of m-bromobenzyl bromide (C-8), and the mixture was stirred at 90 ° C. for 1 hour. Thereafter, excess triethyl phosphite was distilled off under reduced pressure and cooled to room temperature, to obtain 61.24 g (196 mmol, yield 98%) of a phosphate ester (D-8).

  In a nitrogen atmosphere, 10.55 g (35 mmol) of the formyl body (B) obtained in Production Example 1 and 11.83 g (38.5 mmol) of the phosphoric acid ester (D-8) were dissolved in 100 ml of DMF, and Production Example In the same manner as in Example 1, 14.31 g (31.5 mmol, yield 90%) of a stilbene derivative (E-8) was obtained as a yellow powder.

  In a 300 ml four-necked flask equipped with a stirrer, a thermometer, and a reflux tube under a nitrogen atmosphere, 14.31 g (31.5 mmol) of the stilbene derivative (E-8) and 6.35 g of (p-tolyl) phenylamine were added. (34.7 mmol), 3.34 g (34.8 mmol) of sodium tert-butoxide, and 100 ml of sufficiently deoxygenated xylene were added in this order, and the reaction and post-treatment were performed in the same manner as in Production Example 1 to obtain the stilbene derivative (F-8 ) 15.82 g (28.4 mmol, 90% yield) was obtained as a yellow powder.

Under a nitrogen atmosphere, 15.57 g (28.0 mmol) of the stilbene derivative (F-8) was dissolved in 70 ml of DMF while mechanically stirring. Thereafter, while heating to 65 ° C. and maintaining the same temperature, 5.01 g (32.7 mmol) of phosphorus oxychloride (POCl ₃ ) was slowly added dropwise, and the mixture was further stirred at the same temperature for 3 hours and cooled to room temperature. Post-treatment was performed in the same manner as in Production Example 1 to obtain 4.26 g (7.29 mmol, yield 26%) of a formyl derivative (G-8) as a yellow powder.

  Under nitrogen atmosphere, 2.05 g (10.7 mmol) of N-nitrosodiphenylamine, 1.59 g (24.3 mmol) of zinc powder and 22 ml of methanol were charged into the reactor, and 2.9 ml of acetic acid was slowly added while stirring at room temperature. Added dropwise (cooled if necessary). After about 2 hours, the reaction mixture was separated by suction filtration, and the filtrate was added dropwise to a THF solution (with heating under reflux) containing 4.10 g (7.00 mmol) of the formyl form (G-8). The reaction and post-treatment were performed in the same manner as in Production Example 1 to obtain 4.45 g (5.93 mmol, yield 92%) of Exemplary Compound CT-8 as a yellow powder. FIG. 4 shows an IR spectrum (FT / IR-350 spectrometer manufactured by JASCO) of this compound.

(Production Example 4: Synthesis of Exemplified Compound CT-10)
The synthesis | combination of exemplary compound CT-10 was performed according to the following scheme.

In a nitrogen atmosphere, 31.04 g (0.050 mol) of 4 ′, 4 ″ -bis (m, p′-ditolylamino) terphenyl (F-10) was added to 200 ml of DMF with mechanical stirring at 90 to 10 ° C. Thereafter, the mixture was cooled to 65 ° C., and while maintaining the temperature at 65 to 70 ° C., 7.67 g (0.050 mol) of phosphorus oxychloride (POCl ₃ ) was slowly added dropwise and further stirred at the same temperature for 3 hours. After cooling to room temperature, toluene / demineralized water (v / v = 1: 1) was added, and the mixture was sufficiently stirred and separated, and the resulting aqueous layer was further added with toluene, stirred and separated. The layers were combined, washed with 1N NaOH aqueous solution and separated, and the organic layer was washed with demineralized water 2-3 times and separated, and the solvent of the organic layer was distilled off under reduced pressure, and THF was newly added to dissolve the solid. This solution was added dropwise to methanol / water, Crystals were collected by suction filtration, and dried under reduced pressure to obtain 12.65 g (0.020 mol, yield 39%) of formyl form (G-10) as a yellow powder.

  In a nitrogen atmosphere, 5.95 g (0.030 mol) of N-nitrosodiphenylamine, 4.71 g (0.072 mol) of zinc powder and 60 ml of methanol were charged into a reactor, and 8.4 ml of acetic acid was slowly added while stirring at room temperature. Added dropwise (cooled if necessary). After about 2 hours, the reaction mixture was separated by suction filtration, and the filtrate was added dropwise to a THF solution (with heating under reflux) containing 12.65 g (0.020 mol) of formyl (G-10). The heating reflux was continued for about 1 hour, and then the mixture was cooled to room temperature. THF was added to the reaction mixture and stirred until completely dissolved. This solution was dropped into methanol and crystallized. The solid was filtered off with suction, and the solid was dried under reduced pressure at 50 ° C. This was dissolved in a mixed solution of toluene / hexane (v / v = 1: 1), passed through column chromatography (silica gel 500 g, developing solvent: toluene / hexane = 1/1), and concentrated under reduced pressure. By purifying the resulting solid by recrystallization, 14.30 g (0.018 mol, yield 90%) of Exemplary Compound CT-10 was obtained as a yellow powder. FIG. 5 shows an IR spectrum (FT / IR-350 spectrometer manufactured by JASCO) of this compound.

2. Production of electrophotographic photoreceptor (Example 1: Electrophotographic photoreceptor A1)
Using a conductive support in which an aluminum vapor deposition layer (thickness 70 nm) was formed on the surface of a biaxially stretched polyethylene terephthalate resin film (thickness 75 μm), the thickness after drying by a bar coater on the aluminum vapor deposition layer was 1. The undercoat layer dispersion below was applied to a thickness of 25 μm and dried to form an undercoat layer.

  The undercoat layer dispersion was produced as follows. That is, a rutile type titanium oxide having an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were flowed at high speed. The surface-treated titanium oxide obtained by mixing in a high-speed mixing kneader (“SMG300” manufactured by Kawata Co., Ltd.) and mixing at high speed at a rotational peripheral speed of 34.5 m / sec has a mass ratio of methanol / 1-propanol. A dispersion slurry of hydrophobized titanium oxide was obtained by dispersing with a ball mill in a 7/3 mixed solvent. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (P)] / bis described in Examples of JP-A-4-31870 (4-amino-3-methylcyclohexyl) methane [compound represented by the following formula (Q)] / hexamethylenediamine [compound represented by the following formula (R)] / decamethylene dicarboxylic acid [following formula (S) Of the copolyamide having a composition molar ratio of 60% / 15% / 5% / 15% / 5% of the compound represented by the formula] / octadecamethylene dicarboxylic acid [compound represented by the following formula (T)]. After stirring and mixing the pellets with heating to dissolve the polyamide pellets, by performing ultrasonic dispersion treatment, the mass ratio of methanol / 1-propanol / toluene is increased. / 1/2, and a hydrophobic process containing titanium oxide / copolymer polyamide in a weight ratio of 3/1, for an undercoat layer dispersion having a solid content concentration of 18.0%.

  Separately, type A oxytitanium phthalocyanine (showing diffraction peaks at 9.3 °, 10.6 °, and 26.3 ° at the Bragg angle (2θ ± 0.2 °) in the X-ray diffraction spectrum for CuKa characteristic X-ray) 10 The mass part was added to 150 parts by mass of 4-methoxy-4-methyl-2-pentanone, and pulverized and dispersed in a sand grind mill for 1 hour. Thereafter, 100 parts by mass of a 5 mass% 1,2-dimethoxyethane solution of polyvinyl butyral (“Denkabutyral # 6000C” manufactured by Denki Kagaku Kogyo Co., Ltd.) as a binder resin, and phenoxy resin (“PKHH” manufactured by Union Carbide) The coating solution for charge generation layer was prepared by adding 100 parts by mass of 5% by mass 1,2-dimethoxyethane solution. The charge generation layer coating solution was applied onto the undercoat layer of the conductive support with a bar coater so that the film thickness after drying was 0.4 μm, and dried to form a charge generation layer. .

  Separately, 50 parts by mass of Exemplified Compound CT-1 obtained in Production Example 1 as a charge transport material, 100 parts by mass of binder resin, and 0.03 parts by mass of silicone oil as a leveling agent were added in tetrahydrofuran / toluene ( (Mass ratio 8/2) A charge transport layer coating solution was prepared by dissolving in 640 parts by mass of a mixed solvent. In addition, as binder resin, the repeating unit X51 mol% which uses the following 2, 2-bis (4-hydroxy-3-methylphenyl) propane as an aromatic diol component, and 1,1-bis (4-hydroxyphenyl) are shown. ) A polycarbonate resin (viscosity average molecular weight 30000) having a terminal structure derived from pt-butylphenol and comprising 49 mol% of repeating unit Y having 1-phenylethane as an aromatic diol component.

The charge transport layer coating solution is applied onto the charge generation layer with a film applicator so that the film thickness after drying is 20 μm, and is dried to form a charge transport layer. Photoreceptor A1 was produced.
(Example 2: Electrophotographic photoreceptor A2)
An electrophotographic photosensitive member A2 was obtained in the same manner as in Example 1 except that CT-7 was used as a charge transport material instead of the exemplified compound CT-1.

(Example 3: Electrophotographic photoreceptor A3)
An electrophotographic photoreceptor A3 was obtained in the same manner as in Example 1 except that CT-8 was used as a charge transport material instead of the exemplified compound CT-1.

(Example 4: Electrophotographic photoreceptor A4)
An electrophotographic photoreceptor A4 was obtained in the same manner as in Example 1 except that CT-10 was used as the charge transport material instead of the exemplified compound CT-1.

(Comparative Example 1: Electrophotographic photoreceptor P1)
An electrophotographic photosensitive member P1 was obtained in the same manner as in Example 1 except that the following charge transport material a exemplified in Patent Document 1 was used instead of the exemplified compound CT-1.

(Comparative Example 2: Electrophotographic photoreceptor P2)
An electrophotographic photosensitive member P2 was obtained in the same manner as in Example 1 except that the following charge transport material b exemplified in Patent Document 2 was used in place of the exemplified compound CT-1.

(Comparative Example 3: Electrophotographic photoreceptor P3)
An electrophotographic photosensitive member P3 was obtained in the same manner as in Example 1 except that the following charge transport material c exemplified in Patent Document 2 was used instead of the exemplified compound CT-1.

3. Evaluation of Electrophotographic Photoreceptor (1) Electrical Characteristic Evaluation The electrophotographic characteristics of the electrophotographic photosensitive members of Examples 1 to 4 and Comparative Examples 1 to 3 obtained above were measured using a photosensitive member evaluation apparatus (Cynthia-55, Gentec Corporation). And manufactured by the static method as follows.

First, the electrophotographic photosensitive member is discharged with a scorotron charger in a dark place so that the surface potential is about −700 V, and the electrophotographic photosensitive member is charged at a constant speed (125 mm / sec) to be charged. Was measured, and the initial charging voltage (V ₀ ) was determined. Thereafter, the potential drop (DDR) was measured when left for 2.5 seconds. Next, irradiation with 780 nm monochromatic light having an intensity of 1.0 μW / cm ² and irradiation with half exposure energy E _1/2 (μJ / cm ² ) required until the photoreceptor surface potential is changed from −550 V to −275 V, and irradiation The residual potential (V _r ) after 10 seconds was determined. The results are shown in Table 2.

As shown in Table 2, the electrophotographic photoreceptors of Examples 1 to 4 are both compared with the electrophotographic photoreceptors of Comparative Examples 1 to 3 for both half-exposure energy and residual voltage V _r after 10 seconds of irradiation. Showed good results. From this, it can be seen that the electrophotographic photosensitive member of the present invention is excellent in terms of electrical characteristics and is suitable for an image forming apparatus.

(2) Evaluation of ozone resistance The ozone resistance was evaluated by performing an ozone exposure test. The method of ozone exposure test is described below. Using the Kawaguchi Denki Co. EPA8200, Examples 1-4, it was charged by applying a current of 25μA photoreceptor of Comparative Example 1 in corotron charger, and the charging value V _1. Then, 5 hours 1 day ozone 150ppm concentrations to those of the photosensitive member, exposure for 2 days (total exposure 750 ppm · time) was measured similarly charged value after exposure, and this value and _{V 2.} From these values, the charge retention [(V ₂ / V ₁ ) * 100] (%) before and after exposure to ozone was determined. The results are shown in Table 3. Similarly to the evaluation of the electrical characteristics, the residual potentials (respectively V _r1 and V _r2 ) after 10 seconds exposure and before and after ozone exposure were measured, and the difference ΔV _r (V _r2 −V _r1 ) was obtained. Are also shown in Table 3.

  As shown in Table 3, the electrophotographic photoreceptors of Examples 1 to 4 have a higher charge retention before and after ozone exposure than the electrophotographic photoreceptor of Comparative Example 1, and the residual potential difference after 10 seconds of exposure is very small. From this, it was confirmed that the electrophotographic photosensitive member of the present invention has very good ozone resistance and excellent electrical stability.

(3) Evaluation of responsiveness
For the photoconductors obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the electric field strength E of the charge transport layer E = 2.0 × 10 ⁵ (V / cm) and the hole drift mobility at a temperature of 21 ° C. Measured by the method. Table 4 shows the hole drift mobility of each electrophotographic photosensitive member.

  As shown in Table 4, the electrophotographic photosensitive members of Examples 1 to 4 have much faster hole drift mobility than the electrophotographic photosensitive members of Comparative Examples 1 to 3. From this, it can be seen that the electrophotographic photoreceptor of the present invention is excellent in terms of responsiveness and is suitable for an image forming apparatus.

  From the above evaluation results, the electrophotographic photosensitive member of the present invention using the hydrazone compound represented by the formula [I] as a charge transport material is a conventional electron using charge transport materials a, b, and c having similar structures. Compared to a photographic photoreceptor, it was confirmed that the film was extremely excellent in all points of electrical characteristics, oxidation resistance, and charge mobility.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. The electrophotographic photosensitive member and the image forming apparatus accompanied by such changes are also within the technical scope of the present invention, as long as they do not contradict the gist or concept of the invention that can be read from the claims and the entire specification. It must be understood as included.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. 2 is an IR spectrum of compound CT-1 produced in Production Example 1. 4 is an IR spectrum of compound CT-7 produced in Production Example 2. 4 is an IR spectrum of compound CT-8 produced in Production Example 3. 4 is an IR spectrum of compound CT-10 produced in Production Example 4.

Explanation of symbols

1 Photoconductor (Electrophotographic photoconductor)
2 Charging device (charging roller; charging unit)
3 Exposure equipment (exposure section)
4 Development device (development unit)
DESCRIPTION OF SYMBOLS 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper (paper, medium)

Claims (2)

An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains at least one hydrazone compound represented by the following formula [I].

(Wherein ^[I], Ar 1 ~Ar ⁵ each independently shows the aryl group which may have a substituent. However, either Ar ⁴ or Ar ⁵ has the following formula [II] in unless having a substituent represented. a represents an alkenylene group or an arylene group, Y ¹ to Y ³ each independently represent a hydrogen atom or a monovalent substituent. However, Y ¹ ~ Y ³ must not be a hydroxyl group.)

An electrophotographic photosensitive member, a charging portion that charges the electrophotographic photosensitive member, an exposure portion that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, and is formed on the electrophotographic photosensitive member by exposure. An image forming apparatus comprising: a developing unit that develops the electrostatic latent image formed using toner, wherein the electrophotographic photosensitive member is the electrophotographic photosensitive member according to claim 1. Image forming apparatus.

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