JP2008250079A - Electrophotographic photoreceptor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor having small light fatigue. <P>SOLUTION: In the electrophotographic photoreceptor consisting of a photosensitive layer containing a charge generating agent and a charge transfer agent on a conductive support, the photosensitive layer includes a 9-fluorene diphenyl hydrazone compound, and includes a distyryl triaryl amine compound as the charge transfer agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photoreceptor used in electrophotographic printers, copiers, and the like, and more particularly to a photoreceptor with less light fatigue.

  An electrophotographic photoreceptor (hereinafter sometimes referred to as “photoreceptor”) has a function of holding surface charges in the dark, a function of receiving light to generate charges, and a function of receiving light to transport charges. A so-called single-layer photoreceptor that combines these functions in a single layer, a layer that contributes mainly to charge generation, a surface charge in the dark, and a charge transfer during photoreception. There is a so-called function-separated laminated type photoreceptor in which a function-separated layer is laminated on a layer to be separated.

  For example, a Carlson method is applied to image formation by electrophotography using these photoreceptors. Image formation by this method is performed by charging a photoconductor in a dark place by corona discharge, forming an electrostatic latent image such as text or a picture of an original on the surface of the charged photoconductor, The image is developed with toner, and the developed toner image is fixed on a support such as paper. After the toner image is transferred, the photoreceptor is subjected to charge removal, residual toner removal, light charge removal, etc., and then reused. Provided.

  In recent years, electrophotographic photoreceptors using organic substances have been put into practical use due to advantages such as flexibility, thermal stability, and film formability. Recently, a function-separated laminated type photoconductor comprising a charge generation layer containing a charge generation agent and a charge transfer layer containing a charge transfer agent as the photosensitive layer has become mainstream, and in particular, vapor deposition using an organic pigment as the charge generation agent. Many negatively charged photoreceptors have been proposed in which a layer or a layer dispersed in a resin is used as a charge generation layer, and a layer dispersed in a resin using an organic low molecular weight compound as a charge transfer agent is used as a charge transfer layer.

Organic materials have many advantages not found in inorganic materials, but at the same time, organic materials that sufficiently satisfy all the characteristics required for electrophotographic photoreceptors have not been obtained. That is, image quality is deteriorated due to a decrease in charging potential, an increase in residual potential, a change in sensitivity, and the like due to repeated use. Not all the causes of this deterioration have been elucidated, but as one of the factors, charge transfer agent, etc. due to repeated exposure to image exposure and static elimination lamp light, and further exposure to fluorescent light and external light during maintenance May be decomposed or the charge generation layer may be reversibly changed. In order to suppress such deterioration due to light, proposals have been made to add a dye material or a specific charge transfer agent to the charge transfer layer or photosensitive layer serving as a surface layer, and to include an orange dye at the charge transfer layer interface (for example, Patent Document 1) and the inclusion of a hydrazone compound having a specific skeleton and a fluorene compound in the photosensitive layer (for example, see Patent Document 2). However, the present situation is that a sufficient effect is not yet obtained by these conventional techniques.
JP 63-92956 A Japanese Unexamined Patent Publication No. 63-271442

  The present invention has been made in view of the above-described points, and an object thereof is to provide an electrophotographic photoreceptor with little light fatigue.

  The above object is to provide an electrophotographic photosensitive member comprising a photosensitive layer containing a charge generating agent and a charge transfer agent on a conductive support, wherein the photosensitive layer has a compound represented by the formula [I], and charge transfer. It is achieved by having a compound represented by the general formula [II] as an agent.

一般式［ＩＩ］

（式中、Ｒ₃〜Ｒ₅は、各々独立に水素、ハロゲン原子、置換基を有してもよい炭素数１〜６のアルキル基、炭素数６〜１２の置換若しくは無置換のアリール基を表す。） According to the present invention, the compound of formula [I] and the charge transfer agent of general formula [II] are contained in the photosensitive layer by light irradiation, whereby the light resistance effect of the compound of formula [I] and the general formula It is considered that stable photoreceptor characteristics can be obtained by a synergistic effect by the combination with the charge transfer agent of [II], and in particular, light fatigue can be reduced.
Formula [I]

Formula [II]

(In the formula, R _{3 to} R ₅ each independently represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. To express.)

  The mixing ratio of the compound of the formula [I] of the present invention and the charge transfer agent in the photosensitive layer is such that the compound of the formula [I] is 0.5 to 5.0% by weight, preferably 1.0%, based on the charge transfer agent. A range of ˜3.0% by weight is preferable. If it is 0.5% or less, there is no photo-fatigue effect, and if it exceeds 5%, the residual potential in the photoreceptor is increased, causing problems such as a decrease in image density.

According to the present invention, by combining a specific compound and a specific charge transfer agent, an electrophotographic photosensitive member is subjected to image exposure, repeated exposure with a charge-removing lamp light, and further, the surface of the photosensitive member due to light stress caused by fluorescent light or external light during maintenance. Deterioration of the layer is suppressed, and an electrophotographic photoreceptor free from light fatigue can be obtained without affecting the electrophotographic characteristics such as charging, sensitivity, and residual potential of the photoreceptor.
The photoconductor of the present invention is applied to various systems including non-contact charging systems such as corotron and scorotron, contact charging systems such as rollers and brushes, and magnetic one-component, non-magnetic one-component and two-component development systems. A remarkable effect can be obtained in a copying machine and a printer having static elimination light.

  FIG. 1 is a cross-sectional view showing a negatively charged function-separated electrophotographic photoreceptor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a mainly positively charged single-layer type electrophotographic photoreceptor according to an embodiment of the present invention. 1 is a conductive substrate, 2 is an undercoat layer, 3 is a charge generation layer, 4 is a charge transfer layer, 5 is a surface protective layer, 6 is a function-separated type photosensitive layer, and 6a is a single-layer type photosensitive layer.

  The conductive support 1 serves as a support for each of the other layers at the same time as the electrode of the photoreceptor, and may be any of a cylindrical shape, a plate shape, and a film shape. For example, aluminum, brass, stainless steel, nickel Further, a processed metal or a metal alloy such as chromium, titanium, gold, silver, copper, tin, platinum, molybdenum, or indium, or a material obtained by conducting a conductive treatment on glass, resin, or the like may be used.

The undercoat layer 2 is made of a resin-based layer or an anodized oxide film such as alumite, which prevents injection of unnecessary charges from the conductive substrate to the photosensitive layer, covers defects on the substrate surface, and adheres to the photosensitive layer. It is provided as necessary for the purpose of improvement. As resin binder, polyethylene, polypropylene, polystyrene, acrylic resin, vinyl chloride resin, vinyl acetate resin, polyurethane resin, epoxy resin, polyester resin, melamine resin, silicon resin, polybutyral resin, polyamide resin, polyimide resin and their co-polymers Combinations and the like can be used in appropriate combinations. The resin binder may contain metal oxide fine particles. As the metal oxide fine particles, SiO ₂ , TiO ₂ , In ₂ O ₃ , ZrO ₂ or the like can be used.

  The thickness of the undercoat layer 2 depends on the composition of the undercoat layer, but can be arbitrarily set within a range where no adverse effect such as an increase in residual potential occurs when it is repeatedly used continuously. Generally, the range is 0.1 μm to 50 μm, preferably 0.5 μm to 20 μm.

  The charge generation layer 3 is formed by applying an organic photoconductive agent by vacuum deposition or applying a coating liquid in which particles of an organic photoconductive substance are dispersed in a resin binder, and receives light to generate a charge. Further, at the same time as the charge generation efficiency is high, the injection property of the generated charges into the charge transfer layer 4 is important, and it is desirable that injection is good even in a low electric field with little electric field dependency. Since the charge generation layer only needs to have a charge generation function, its film thickness is determined by the light absorption coefficient of the charge generation agent and is generally 5 μm or less, and preferably 1 μm or less. The charge generation layer can also be used with a charge transfer agent as a main component and a charge transfer agent added thereto. As the charge generator, phthalocyanine pigments such as metal-free phthalocyanine, titanyl phthalocyanine, tin phthalocyanine, azo pigments, anthanthrone pigments, perylene pigments, perinone pigments, squarylium pigments, thiapyrylium pigments, quinacridone pigments, and the like can be used. These pigments may be used in combination.

  Examples of the resin binder include polycarbonate resin, polyester resin, polyamide resin, polyurethane resin, epoxy resin, polyvinyl butyral resin, polyvinyl acetal resin, vinyl chloride resin, phenoxy resin, silicon resin, methacrylate ester resin and copolymers thereof. It can be used in combination as appropriate.

  The charge transfer layer 4 is a film in which a charge transfer agent is dispersed in a resin binder. The charge transfer layer 4 retains the charge of the photoreceptor as an insulator layer in the dark, and transports the charge injected from the charge generation layer when receiving light. Demonstrate. The charge transfer layer 4 includes a charge transfer agent and a resin binder as main components.

式〔ＩＩｂ〕

式〔ＩＩｃ〕

式〔ＩＩｄ〕

The compounds of the general formula [II] of the present invention are not limited to these, but the compounds represented by the formulas [IIa] to [IId] are particularly preferable because of their good compatibility with the compounds of the formula [I].
Formula [IIa]

Formula [IIb]

Formula [IIc]

Formula [IId]

  In this case, the content of the compound represented by the general formula [II] in the charge transfer layer is preferably 0.3 to 2.0 parts by weight with respect to 1 part by weight of the binder resin. If the content of this compound is less than 0.3 parts by weight, the electrical characteristics deteriorate, for example, the residual potential increases. On the other hand, when the amount is more than 2.0 parts by weight, mechanical properties such as wear resistance are deteriorated.

  Furthermore, the compound represented by the general formula [II] and other charge transfer agents can be mixed and used. In this case, the content ratio of the compound of the general formula [II] and other compounds is [II]: other compounds = 50: 50 to 5:95, preferably 30:70 to 5:95.

  In the present invention, the charge transfer agent may contain the following compounds. Polyvinyl carbazole, halogenated polyvinyl carbazole, polyvinyl pyrene, polyvinyl indoloquinoxaline, polyvinyl benzothiophene, polyvinyl anthracene, polyvinyl acridine, polyvinyl pyrazoline, polyacetylene, polythiophene, polypyrrole, polyphenylene, polyphenylene vinylene, polyisothianaphthene, polyaniline, polydiacetylene Conductive polymer compounds such as polyheptadiene, polypyridinediyl, polyquinoline, polyphenylene sulfide, polyferrocenylene, polyperinaphthylene, and polyphthalocyanine can be used. In addition, as low molecular weight compounds, trinitrofluorenone, tetracyanoethylene, tetracyanoquinodimethane, quinone, diphenoquinone, naphthoquinone, anthraquinone and derivatives thereof, polycyclic aromatic compounds such as anthracene, pyrene, phenanthrene, indole, carbazole Nitrogen-containing heterocyclic compounds such as imidazole, fluorenone, fluorene, oxadiazole, oxazole, pyrazoline, hydrazone, triphenylmethane, triphenylamine, enamine, stilbene, and butadiene compounds can be used. Further, a polymer solid electrolyte in which a polymer compound such as polyethylene oxide, polypropylene oxide, polyacrylonitrile, polymethacrylic acid or the like is doped with a metal ion such as Li ion can also be used. Further, an organic charge transfer complex formed of an electron donating compound typified by tetrathiafulvalene-tetracyanoquinodimethane and an electron accepting compound can be used, and even if only one of these is added, 2 Desired photoreceptor characteristics can be obtained even if a mixture of more than one kind of compounds is added.

  As the resin binder for the charge transfer layer, polycarbonate resin, styrene resin, acrylic resin, styrene-acrylic resin, ethylene-vinyl acetate resin, polypropylene resin, vinyl chloride resin, chlorinated polyether, vinyl chloride-vinyl acetate resin, polyester resin , Furan resin, nitrile resin, alkyd resin, polyacetal resin, polymethylpentene resin, polyamide resin, polyurethane resin, epoxy resin, polyarylate resin, diarylate resin, polysulfone resin, polyethersulfone resin, polyallylsulfone resin, silicone resin, Ketone resin, polyvinyl butyral resin, polyether resin, phenol resin, EVA (ethylene / vinyl acetate / copolymer) resin, ACS (acrylonitrile / chlorinated polyethylene / styrene) resin There are resins such as photocuring resins such as ABS (acrylonitrile, butadiene, styrene) resin and epoxy allylate.

  They may be used alone or in the form of a copolymer, or may be used in combination of two or more. It is preferable to use a mixture of resins having different molecular weights because the hardness and wear resistance can be improved. In addition to mechanical, chemical and electrical stability, adhesion and the like, compatibility with the charge transfer agent is important.

  The film thickness of the charge transfer layer is preferably in the range of 3 to 50 μm, more preferably 10 to 40 μm, in order to maintain a practically effective surface potential. The surface protective layer 5 can be provided as required, is made of a material that is excellent in mechanical stress durability and is chemically stable, and has a function of receiving and holding a corona discharge charge in a dark place. In addition, the charge generation layer has the ability to transmit sensitive light, transmits light during exposure, reaches the charge generation layer, and receives the injection of generated charges to neutralize and extinguish surface charges. is required.

In the present invention, a surface protective layer may be provided as necessary. Surface protective layer is polyvinyl butyral resin, polycarbonate resin, nylon resin, polyurethane resin, polyarylate resin, modified silicone resin, acrylic modified silicone resin, epoxy modified silicone resin, alkyd modified silicone resin, polyester modified silicone resin, urethane modified silicone resin In addition to the above, silicon resin as a hard coating agent can be applied. These modified silicone resins can be used alone, but for the purpose of improving durability, a condensate of a metal alkoxy compound capable of forming a film mainly composed of SiO ₂ , TiO ₂ , In ₂ O ₃ , and ZrO ₂ ; A mixture of

  The film thickness of the surface protective layer depends on the composition of the protective layer, but can be arbitrarily set within a range where no adverse effect such as an increase in residual potential occurs when repeatedly used. In the single-layer type photosensitive layer 6a, a charge generator and a charge transfer agent are dispersed in a resin binder.

  The film thickness of the single-layer type photosensitive layer 6a is in the range of 3 to 50 μm, more preferably 10 to 40 μm, in order to maintain a practically effective surface potential.

  In addition, antioxidants, ultraviolet absorbers, radical scavengers, softeners, curing agents, cross-linking agents, etc. are added to the photosensitive layers of the above-mentioned laminated type and single layer type photoreceptors as long as the characteristics are not impaired. Thus, the characteristics, durability, and mechanical characteristics of the photoreceptor can be improved.

  In particular, the antioxidant contributes to improving the durability of the photoreceptor and is useful. Among them, the photosensitive layer preferably contains an aromatic amine-based antioxidant, such as N-phenyl-1-naphthylamine, N-phenyl-N′-isopropyl-p-phenylenediamine, N, N-diethyl- p-phenylenediamine, N-phenyl-N'-ethyl-2-methyl-p-phenylenediamine, N-ethyl-N-hydroxyethyl-p-phenylenediamine, alkylated diphenylamine, N, N'-diphenyl-p- Phenylenediamine, N, N'-diallyl-p-phenylenediamine, N-phenyl-1,3-dimethylbutyl-p-phenylenediamine, 4,4'-dioctyl-diphenylamine, 4,4'-dioctyl-diphenylamine, 6 -Ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, 2,2 4-trimethyl-1,2-dihydroquinoline, N- phenyl -β- naphthylamine, N, can be given N'- di-2-naphthyl -p- phenylenediamine.

  Phenol antioxidants include 2,6-di-tert-butylphenol, 2,6-di-tert-4-methoxyphenol, 2-tert-butyl-4-methoxyphenol, 2,4-dimethyl-6-tert. -Butylphenol, 2,6-di-tert-butyl-4-methylphenol, butylated hydroxyanisole, stearyl-propionate-β- (3,5-di-tert-butyl-4-hydroxyphenyl), α-tocopherol, monophenols such as β-tocopherol, n-octadecyl-3- (3′-5′-di-tert-butyl-4′-hydroxyphenyl) propionate, 2,2′-methylenebis (6-tert-butyl-4) -Methylphenol), 4,4'-butylidene-bis- (3-methyl-6-tert-butyl) Enol), 4,4′-thiobis (6-tert-butyl-3-methylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3 , 5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3 (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate] Polyphenols such as methane are preferred, and one or more of them can be simultaneously contained in the photosensitive layer.

Ultraviolet absorbers include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- (3,5-di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5 -Di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-amyl-2-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5 ' -Tert-octylphenyl) benzotriazoles such as benzotriazole, phenyl salicylate, salicylic acid-p-ter - butylphenyl, salicylates such as salicylic acid -p- octylphenyl is preferred. Of these, benzotriazole-based ultraviolet absorbers are particularly preferred.
One or two or more of the above antioxidants and / or ultraviolet absorbers can be simultaneously contained in the photosensitive layer.

  The addition amount of the phenol-based antioxidant or amine-based antioxidant added to the electrophotographic photoreceptor of the present invention is preferably in the range of 3 to 20% by weight with respect to the binder resin. On the other hand, the addition amount of the ultraviolet absorber is preferably 3 to 30% by weight with respect to the binder resin.

  Furthermore, the addition of a dispersion stabilizer, an anti-settling agent, an anti-coloring agent, a leveling agent, an antifoaming agent, a thickener, a matting agent, etc. can improve the finished appearance of the photoreceptor and the life of the coating solution.

  In particular, for the purpose of improving the stability to heat, ozone, etc., an antioxidant may be added appropriately. Compounds used for such purposes include chromanol derivatives such as tocopherol or etherified or esterified compounds, polyarylalkane compounds, hydroquinone derivatives and monoetherified or dietherified compounds thereof, benzophenone derivatives, benzotriazole derivatives, Examples include thioether compounds, phenylenediamine derivatives, phosphonic acid esters, phosphite esters, phenol compounds, hindered phenol compounds, linear amine compounds, cyclic amine compounds, hindered amine compounds, and the like.

  Furthermore, an electron-accepting substance is included in the photosensitive layer of the above-mentioned multilayer type and single layer type photoconductors as necessary for the purpose of improving sensitivity, reducing residual potential, or reducing characteristic fluctuations during repeated use. Examples of electron acceptors include succinic anhydride, maleic anhydride, dibromosuccinic anhydride, phthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, pyromellitic anhydride, pyromellitic acid, trimellitic acid, Examples include compounds having a large electron affinity such as trimellitic anhydride, phthalimide, 4-nitrophthalimide, tetracyanoethylene, tetracyanosinodimethane, chloranil, bromanyl, o-nitrobenzoic acid.

  Solvents used in the coating solution include alcohols such as methanol, ethanol, n-propanol, i-propanol and butanol, saturated aliphatic hydrocarbons such as pentane, hexane, heptane, octane, cyclohexane and cycloheptane, toluene and xylene. Aromatic hydrocarbons such as dichloromethane, chlorinated hydrocarbons such as dichloromethane, dichloroethane, chloroform, chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran (THF), methoxyethanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone , Esters such as ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, N, N-dimethylformamide, dimethylsulfoxy And the like. These may be used alone or as a mixture of two or more solvents.

  Alkyd resin (Beckolite M-6401-50 manufactured by Dainippon Ink and Chemicals) and amino resin (Super Becamine G-821-60 manufactured by Dainippon Ink and Chemicals, Inc.) on a cylindrical drum made of uncut aluminum with a diameter of 24 mm ) In a ratio of 65:35, and the mixed resin and titanium oxide (CR-EL Ishihara Sangyo Co., Ltd.) in a ratio of 1: 3 are dissolved in methyl ethyl ketone to form a coating solution having a thickness of 1.5 μm. Formed with.

  Next, 15 g of oxytitanium phthalocyanine powder having a maximum peak at an X-ray diffraction angle Cukα (2θ ± 0.2 degrees) of 27.3 degrees in FIG. 3 was added to glass beads and 500 ml of 1,3 dioxolane with polyvinyl butyral resin (BX-1 A solution in which 10 g of Sekisui Chemical Co., Ltd.) was dissolved was added and dispersed with a sand mill disperser for 20 hours. The resulting dispersion was filtered to remove the glass beads to prepare a charge generation layer coating solution. This was dip-coated on the undercoat layer and dried to form a charge generation layer having a thickness of 0.2 μm.

  Next, polycarbonate resin (manufactured by Teijin Kasei Co., Ltd.) as a binder resin, a compound of formula I, a compound represented by formula [J] as a charge transfer agent, and N— as an aromatic amine-based antioxidant phenyl-1-naphthlamine and 2- (5-methyl-2-hydroxyphenyl) benzotriazole as an ultraviolet absorber are prepared in a weight ratio of 1: 0.02: 1: 0.05: 0.05, respectively. It melt | dissolved in tetrahydrofuran and prepared the coating liquid for charge transfer layers. The substrate on which the charge generation layer was formed was dip-coated in the charge transfer layer coating solution and dried at 130 ° C. for 60 minutes to form a charge transfer layer having a thickness of 20.0 μm. Thus, an electrophotographic photosensitive member was produced.

  An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that instead of the charge transfer agent used in Example 1, the charge transfer agent represented by Formula [IIb] was used.

  An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that instead of the charge transfer agent used in Example 1, the charge transfer agent represented by the formula [IIc] was used.

  An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that instead of the charge transfer agent used in Example 1, the charge transfer agent represented by the formula [IId] was used.

  An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the weight ratio of the compound of Formula 1 and the charge transfer agent used in Example 1 was changed to 0.005: 1.

  An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the weight ratio of the compound of formula 1 and the charge transfer agent used in Example 1 was changed to 0.05: 1.

  An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that an azo pigment of the following formula was used in place of the oxytitanium phthalocyanine used in Example 1.

Formula [A]

<Comparative Example 1>
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the following charge transfer agent was used instead of the charge transfer agent used in Example 1.
Formula [B]

<Comparative example 2>
An electrophotographic photosensitive member was prepared in the same manner as in Example 1 except that the following charge transfer agent was used instead of the charge transfer agent used in Example 1.
Formula [C]

<Comparative Example 3>
An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that the compound of formula [I] used in Example 1 was omitted.

<Comparative Example 4>
Except for the compound of the formula [I] used in Example 1, and in place of the charge generator used in Example 1, the same as in Example 1 except that the charge generator used in Comparative Example 1 was used. Thus, an electrophotographic photosensitive member was prepared.

Photoconductor evaluation <Evaluation of electrical characteristics with a simple measuring instrument>
A photosensitive drum evaluation device (dynamic mode measurement) was used for the function-separated type photoreceptors produced in Examples 1 to 7 and Comparative Examples 1 to 4, and the electrophotographic characteristics were evaluated under the following conditions.

Using an electrophotographic photosensitive member evaluation apparatus (manufactured by Yamanashi Denshi Kogyo Co., Ltd.), the electrophotographic photosensitive member produced in the examples and comparative examples is subjected to the surface potential of the photosensitive member by the scorotron method in an environment of temperature 23 ° C. and humidity 50%. When the discharge current is adjusted so that the voltage becomes −700 V, the electrophotographic photosensitive member is charged and irradiated with a semiconductor laser having a wavelength of 650 nm, the surface potential of the photosensitive member is 1 with an exposure energy amount of 0.13 to 0.15 μJ. The attenuation was adjusted to / 2 (-350 V). Further, the photosensitive member residual potential (VL) was 20 to 40 V with an exposure energy amount of 0.6 μJ / cm ² .

  The electrophotographic photoreceptor was irradiated continuously with a 1000 lux white fluorescent lamp for 5 minutes, 10 minutes, and 15 minutes, respectively, and the fatigue characteristics due to light were measured. At this time, the surface potential (VO), sensitivity potential (VH), and residual potential (VL) of the photoconductor before and after irradiation were measured. For neutralization, an LED (20 μW) having a wavelength of 660 nm was used. The drum rotation speed of the electrophotographic photosensitive member was 150 rpm, and the time from when the laser beam was irradiated until the potential was measured (movement time from the exposure position to the measurement position) was 0.06 seconds. The results are shown in Table 2.

<Evaluation of actual image (halftone evaluation)>
The electrophotographic photosensitive members produced in Examples 1 to 6 and Comparative Examples 1 to 3 were copied from a color printer (Ricoh Co., Ltd .: CX3000), and the electrophotographic photosensitive members produced in Example 7 and Comparative Example 4 were copied from a copier (Toshiba Tech). Mounted on a company-made PRECIO: 4560), a halftone image was output in a room temperature environment at a temperature of 23 ° C. and a humidity of 50%, and the image density difference (measured with a Macbeth densitometer) was compared and visually evaluated. (Halftone image = Light / dark difference between the irradiated and non-irradiated areas)
The results are shown in Table 3.

  In Table 2, the surface potentials V0 and VH are superior to the initial set values V0 of 700 (V) and VH350 (V) as the amount of potential change after light irradiation is smaller.

  In Examples 1 to 7, the combination of the compound of Formula 1 of the present invention and the charge transfer agent shows a characteristic that is resistant to light fatigue in the fatigue test, and is good in charging potential, sensitivity potential, residual potential, and image density. It was something. In Example 5, when the amount of the compound of Formula 1 is small, the surface potential and the sensitivity potential are slightly inferior to Example 1, but no density difference appears on the image. In Example 6, when the amount of the compound of Formula 1 is large, the potential difference between the surface potential and the sensitivity potential when the irradiation time is varied is small compared to Example 1, and the light resistance is improved while the residual potential is increased. Increased slightly. Both were usable ranges.

  In Comparative Examples 1 and 2, the initial VH, VL, and image density, which are normally unusable, were not evaluated by visual evaluation due to the combination with other charge transfer agents. Comparative Examples 3 and 4 were examples in which Compound 1 was excluded, and V0, VH, and image density were greatly changed, and the light fatigue characteristics were particularly bad.

  As can be seen from the above description, the photoconductor in which the compound of the formula [I] and the specific charge transfer agent based on the present invention are combined stabilizes the electrophotographic characteristics such as charging, sensitivity, residual potential, etc. Is suppressed.

It is sectional drawing which shows an example of a laminated type electrophotographic photoreceptor. It is sectional drawing which shows an example of a single layer type electrophotographic photoreceptor. It is an X-ray diffraction pattern of oxytitanium phthalocyanine used in the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Undercoat layer 3 Charge generation layer 4 Charge transfer layer 5 Surface protection layer 6 Photosensitive layer 6a Photosensitive layer

Claims (4)

An electrophotographic photosensitive member comprising a photosensitive layer containing a charge generating agent and a charge transfer agent on a conductive support, wherein the photosensitive layer has a compound 9-full orange phenylhydrazone represented by the formula [I], and charge transfer An electrophotographic photoreceptor comprising a compound represented by the general formula [II] as an agent.
Formula [I]

Formula [II]

(In the formula, R _{3 to} R ₅ each independently represent a hydrogen atom, a halogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms. To express.)   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer contains an aromatic amine-based antioxidant.   2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer contains a benzotriazole ultraviolet absorber.   The mixing ratio of the compound of the formula [I] and the charge transfer agent is such that the compound of the formula [I] is 0.5 to 5.0% by weight with respect to the charge transfer agent. Electrophotographic photoreceptor.

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