JP2005121887A - Fluorenone derivative, electrophotographic photoreceptor using the compound and electrophotographic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new compound suitable for use as an electron transport material in an organic electrophotographic photoreceptor, and an electrophotographic photoreceptor using the same and having higher sensitivity than a conventional one. <P>SOLUTION: The fluorenone derivative is represented by formula (1) wherein X represents =O or =C(CN)<SB>2</SB>and R<SB>1</SB>-R<SB>8</SB>each independently represent a group selected from the group consisting of H, a substituted or unsubstituted aryl, a substituted or unsubstituted aryloxy, a substituted or unsubstituted arylthio, a substituted or unsubstituted alkyl, a substituted or unsubstituted alkyloxy, a substituted or unsubstituted alkylthio, a substituted or unsubstituted aralkyl and a substituted or unsubstituted alkoxycarbonyl with the proviso that at least one of R<SB>1</SB>-R<SB>8</SB>is a substituted or unsubstituted arylthio or an aryl halide. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel fluorenone derivative and an electrophotographic photosensitive member using the compound, more specifically, an electrophotographic photosensitive member used in an image forming apparatus such as an electrostatic copying machine, a facsimile machine, a laser beam printer, and the like. The present invention relates to an electrophotographic apparatus provided with a photoreceptor.

  In recent years, organic electrophotographic photoreceptors (OPC) have been widely put into practical use from the viewpoints of pollution-free, low cost, and various design of photoreceptor characteristics from the degree of freedom of material selection. The photosensitive layer of OPC is a laminated type photoconductor in which a charge generation layer and a charge transport layer are laminated, a so-called function separation type photoconductor, or a charge generation agent and a charge transport agent dispersed in a single photosensitive layer. A so-called single-layer type photoconductor has been proposed.

  The charge transport agents used in these photoreceptors are required to have a high carrier mobility, but most of the charge transport agents with a high carrier mobility have a hole transport property, so that they are put to practical use. From the viewpoint of mechanical strength, the OPC is limited to a negatively charged laminated photoconductor in which a charge transport layer is provided on the outermost layer. However, the negatively charged OPC uses negative corona discharge, so it is more unstable than the positive one and has a large amount of ozone, which can cause deterioration of the photoconductor and adversely affect the use environment. Etc. is a problem.

  Therefore, in order to solve such problems, OPC that can be used in the positive charging process is effective. For this purpose, it is necessary to use an electron transport agent as a charge transport agent. For example, in Patent Document 1, a compound having a diphenoquinone structure or a benzoquinone structure is used as an electron transport agent for an electrophotographic photoreceptor. Proposed. Patent Document 2 proposes the use of a benzenetetracarboxylic acid diimide compound as an electron transport agent for an electrophotographic photoreceptor.

However, conventional electron transporting agents such as a diphenoquinone derivative, a benzoquinone derivative, and a benzenetetracarboxylic acid diimide compound have problems such as precipitation because they have low compatibility with the binder resin. Further, since the amount that can be dispersed in the photosensitive layer is limited, the hopping distance becomes long, and the electron transfer hardly occurs in a low electric field. Therefore, it has been extremely difficult to make a conventional photoreceptor containing an electron transport agent excellent in electron transport ability.
JP-A-1-206349 JP-A-5-142812

The object of the present invention is to solve the above technical problems and provide a novel compound suitable as an electron transporting agent in an organic electrophotographic photoreceptor and an electrophotographic photoreceptor having higher sensitivity than the conventional one using the compound. There is.

  As a result of intensive studies to solve the above problems, the present inventors have found that the fluorenone derivative represented by the general formula (1) has good dispersibility in the resin and is excellent in thin film formation and electron transport properties. As a result, it has been found that a high-sensitivity and high-performance element can be produced by using it as an electron transporting agent in an electrophotographic photosensitive member.

That is, the present invention
1. A fluorenone derivative represented by the general formula (1),

…（１）
[式中、Ｘは＝Ｏあるいは＝Ｃ（ＣＮ）_２を表し、
Ｒ_１〜Ｒ_８は、それぞれ独立に水素原子、置換または無置換のアリール基、置換または無置換のアリールオキシ基、置換または無置換のアリールチオ基、置換または無置換のアルキル基、置換または無置換のアルキルオキシ基、置換または無置換のアルキルチオ基、置換または無置換のアラルキル基、置換または無置換のアルコキシカルボニル基からなる群より選ばれる基を表すが、いずれか一つは置換または無置換のアリールチオ基またはハロゲン化アリール基である。]
２．導電性基体上に感光層が設けられた電子写真感光体において、該感光層中に、上記１記載の化合物を含有することを特徴とする電子写真感光体、
３．上記２記載の電子写真感光体を備えた電子写真装置、

に関する。

... (1)
[Wherein X represents = O or = C (CN) ₂ ;
R _{1 to} R ₈ are each independently a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkyl group, substituted or unsubstituted Represents a group selected from the group consisting of an alkyloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aralkyl group, and a substituted or unsubstituted alkoxycarbonyl group, any one of which is substituted or unsubstituted An arylthio group or a halogenated aryl group. ]
2. An electrophotographic photosensitive member in which a photosensitive layer is provided on a conductive substrate, wherein the photosensitive layer contains the compound described in 1 above,
3. An electrophotographic apparatus comprising the electrophotographic photosensitive member according to 2 above,

About.

The novel fluorenone compound obtained by the present invention has excellent electron transport properties, and when the compound is used in an electrophotographic photoreceptor, the dispersibility in the resin is improved, and the electrical properties and repeat stability are also excellent. A durable electrophotographic photoreceptor is obtained.

Hereinafter, the present invention will be described in detail.
The novel fluorenone derivative of the present invention is a compound represented by the general formula (1).

…（１）
[式中、Ｘは＝Ｏあるいは＝Ｃ（ＣＮ）_２を表し、
Ｒ_１〜Ｒ_８は、それぞれ独立に水素原子、置換または無置換のアリール基、置換または無置換のアリールオキシ基、置換または無置換のアリールチオ基、置換または無置換のアルキル基、置換または無置換のアルキルオキシ基、置換または無置換のアルキルチオ基、置換または無置換のアラルキル基、置換または無置換のアルコキシカルボニル基からなる群より選ばれる基を表すが、いずれか一つは置換または無置換のアリールチオ基またはハロゲン化アリール基である。]

... (1)
[Wherein X represents = O or = C (CN) ₂ ;
R _{1 to} R ₈ are each independently a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkyl group, substituted or unsubstituted Represents a group selected from the group consisting of an alkyloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aralkyl group, and a substituted or unsubstituted alkoxycarbonyl group, any one of which is substituted or unsubstituted An arylthio group or a halogenated aryl group. ]

In the compound represented by the general formula (1), the substituent X represents ═O or ═C (CN) ₂ . These are determined not only by transport properties but also by energy level matching with the charge generating agent.

In the compound represented by the general formula (1), the substituents R _{1 to} R ₈ are each independently a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group. A group selected from the group consisting of a group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkyloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aralkyl group, and a substituted or unsubstituted alkoxycarbonyl group Any one is a substituted or unsubstituted arylthio group or a halogenated aryl group.

  The aryl group is not particularly limited, but is preferably a substituted or unsubstituted carbocyclic aromatic group having 6 to 30 carbon atoms, a substituted or unsubstituted heterocyclic aromatic group having 3 to 25 carbon atoms, A substituted or unsubstituted carbocyclic aromatic group having 6 to 25 carbon atoms, a substituted or unsubstituted heterocyclic aromatic group having 4 to 12 carbon atoms is more preferable, and a substituted or unsubstituted group having 6 to 22 carbon atoms is preferred. A carbocyclic aromatic group and a substituted or unsubstituted heterocyclic aromatic group having 4 to 10 carbon atoms are more preferable. Specific examples include a phenyl group, a naphthyl group, an anthryl group, a biphenyl group, a thienyl group, a bithienyl group, a furyl group, and a pyridyl group.

  The aryloxy group is not particularly limited, but among them, a substituent having the above aryl group as an aromatic component is preferable. Specific examples include a phenyloxy group, a naphthyloxy group, a biphenyloxy group, a thienyloxy group, and a bithienyloxy group.

  Although there is no restriction | limiting in particular as an arylthio group, Especially the substituent which uses the said aryl group as an aromatic component is preferable. Specific examples include a phenylthio group, a naphthylthio group, a biphenylthio group, a thienylthio group, and a bithienylthio group.

  Although there is no restriction | limiting in particular as an alkyl group, Especially a C1-C6 linear, branched or cyclic alkyl group is preferable. Specifically, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, s-butyl group, t-butyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, cyclopentyl Group, n-hexyl group, 1-methylpentyl group, 4-methyl-2-pentyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, cyclohexyl group and the like.

  Although there is no restriction | limiting in particular as an alkyloxy group, Especially the substituent which uses the said alkyl group as an aliphatic component is preferable. Specific examples include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, a butoxy group, a t-butoxy group, a pentyloxy group, and a hexyloxy group.

  Although there is no restriction | limiting in particular as an alkylthio group, Especially the substituent which uses the said alkyl group as an aliphatic component is preferable. Specific examples include a methylthio group, an ethylthio group, an n-propylthio group, an isopropylthio group, a butylthio group, a t-butylthio group, a pentylthio group, and a hexylthio group.

  Although there is no restriction | limiting in particular as an aralkyl group, Especially a C6-C14 aralkyl group is preferable. Specific examples include benzyl group, 1-phenylethyl group, 3-phenylpropyl group, 4-phenylbutyl group, 5-phenylpentyl group, 6-phenylhexyl group, benzhydryl group, trityl group, phenethyl group and the like. .

  The alkoxycarbonyl group is not particularly limited, but an alkoxycarbonyl group having 1 to 6 carbon atoms is particularly preferable. Specific examples include a methoxycarbonyl group, an ethoxycarbonyl group, and a propoxycarbonyl group.

In addition, the aryl group, aryloxy group, arylthio group, alkyl group, alkyloxy group, alkylthio group, aralkyl group, and alkoxycarbonyl group corresponding to the substituents R _{1 to} R ₈ may have a substituent. Specifically, hydroxyalkyl group, alkoxyalkyl group, monoalkylaminoalkyl group, dialkylaminoalkyl group, halogen-substituted alkyl group, alkoxycarbonylalkyl group, carboxyalkyl group, alkanoyloxyalkyl group, aminoalkyl group, halogen atom, amino group In addition to a hydroxy group, a carboxyl group that may be esterified, a cyano group, etc., an alkyl group that may have a substituent having 1 to 4 carbon atoms or a substituent that has 1 to 6 carbon atoms may be included. Good alkoxy groups and the like can be mentioned. In addition, the substitution position of these substituents is not particularly limited.

  Although the specific example of a compound shown by the said General formula (1) below is given, it is not limited to these compounds.

  The method for synthesizing the fluorenone compound of the present invention is not particularly limited, and will be described by a known synthesis method, for example, taking the production method of specific example (1) as an example. That is, it is obtained by reacting 4-fluorothiophenoxide copper (I) with a halogenated fluorenone in a polar organic solvent.

  The reaction temperature is in the range of 100 to 200 ° C, preferably in the range of 130 to 180 ° C. When the reaction temperature exceeds 180 ° C., by-products increase, and the yield of the target compound may decrease. Moreover, when reaction temperature is lower than 100 degreeC, reaction rate may be slow and may not be practical.

  The reaction solvent is preferably a polar organic solvent. The polar organic solvent is not particularly limited, and examples thereof include N-methyl-2-pyrrolidone, N-propyl-2-pyrrolidone, dimethylacetamide, dimethylformamide, and dimethyl sulfoxide.

  Next, the fluorenone compound and malononitrile are dissolved in dehydrated methanol, and a catalytic amount of piperidine is added dropwise and stirred at room temperature. After completion of the reaction, the target product can be obtained by filtering to take out unreacted malononitrile and the target product, recrystallizing and purifying.

  Embodiments of the organic electrophotographic photoreceptor of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram showing an embodiment of the photoreceptor of the present invention. Reference numeral 1 denotes a conductive substrate, 2 denotes an undercoat layer, 3 denotes a photosensitive layer, 4 denotes a protective layer, and the undercoat layer 2 and the protective layer 4 are provided as necessary. The photosensitive layer 3 has a charge generation function and a charge transport function, and includes a single layer type in which both functions are provided in one layer, and a stacked type in which the charge generation layer and the charge transport layer are separated.

  The electrophotographic photosensitive member of the present invention can be applied to both a single layer type and a laminated type, but the effect by using the fluorenone compound (1) of the present invention is remarkably exhibited in the single layer type photosensitive member. The single-layer type photoreceptor is obtained by providing a single photosensitive layer containing at least a fluorenone compound (1) which is an electron transport agent, a charge generator and a resin binder on a conductive substrate. Such a single-layer type photosensitive layer can handle both positive and negative charges with a single structure, but is preferably used with positive charge that does not require negative corona discharge. This single-layer type photoreceptor has advantages such as simple layer structure and excellent productivity, suppression of the occurrence of film defects in the photosensitive layer, and improvement in optical characteristics because there are few interfaces between layers. Have

  On the other hand, a multilayer photoreceptor is obtained by laminating a charge generation layer containing a charge generation agent and a charge transport layer containing a charge transfer agent in this order or in the reverse order on a conductive substrate. . However, since the charge generation layer is much thinner than the charge transport layer, it is preferable to form the charge generation layer on the conductive substrate and to form the charge transport layer thereon for protection. .

  The conductive substrate 1 serves as a support for each of the other layers simultaneously with the function as the electrode of the photoreceptor, and may be any of a cylindrical shape, a plate shape, and a film shape, and the materials thereof are iron, aluminum, copper, tin And a single metal such as platinum, stainless steel, and nickel, a plastic material obtained by depositing or laminating the above metal and conducting a conductive treatment, or glass coated with aluminum iodide, tin oxide, indium oxide, or the like.

  The undercoat layer 2 can be provided as necessary, and is composed of a resin-based layer, an anodized oxide film, or the like, and prevents unnecessary charge injection from the conductive substrate to the photosensitive layer. It is provided as necessary for the purpose of defect coating, improvement in adhesion of the photosensitive layer, and the like. As the resin binder for the undercoat layer, polycarbonate resin, polyester resin, polyvinyl acetal resin, polyvinyl butyral resin, vinyl chloride resin, vinyl acetate resin, polyethylene, polypropylene, polystyrene, acrylic resin, polyurethane resin, epoxy resin, melamine resin, Silicone resins, polyamide resins, polystyrene resins, polyacetal resins, polyarylate resins, polysulfone resins, methacrylic ester polymers, copolymers thereof, and the like can be used in appropriate combinations. The resin binder includes silicon oxide (silica), titanium oxide, zinc oxide, calcium oxide, aluminum oxide (alumina), metal oxides such as zirconium oxide, metal sulfides such as barium sulfide and calcium sulfide, and silicon nitride. Further, it may contain metal nitride such as aluminum nitride, metal oxide fine particles and the like.

  Although the thickness of the undercoat layer depends on the composition of the undercoat layer, it 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.

  In the case of the function separation type, the photosensitive layer 3 is mainly composed of two layers of a charge generation layer and a charge transport layer, and in the case of a single layer type, it is composed of one layer. The charge generation layer is formed by vacuum-depositing an organic photoconductive substance or applying a material in which particles of an organic photoconductive substance are dispersed in a resin binder, and generates charge by receiving light. In addition, the injection efficiency of the generated charges into the charge transport layer is important at the same time as the charge generation efficiency is high, and it is desirable that the injection is good even in a low electric field with little electric field dependency.

  The charge generation layer can also be used with a charge generation agent as a main component and a charge transport agent added thereto. As the charge generating agent, a phthalocyanine pigment, an azo pigment, an anthrone pigment, a perylene pigment, a perinone pigment, a squarylium pigment, a thiapyrylium pigment, a quinacridone pigment, or the like may be used, or these pigments may be used in combination. Especially as azo pigments, disazo pigments, trisazo pigments, as perylene pigments, N, N′-bis (3,5-dimethylphenyl) -3,4: 9,10-perylenebis (carboximide), as phthalocyanine pigments Is preferably metal-free phthalocyanine, copper phthalocyanine, titanyl phthalocyanine, and further X-type metal-free phthalocyanine, τ-type metal-free phthalocyanine, ε-type copper phthalocyanine, α-type titanyl phthalocyanine, β-type titanyl phthalocyanine, Y-type titanyl phthalocyanine, amorphous Titanyl phthalocyanine is preferred.

  Moreover, the charge generators exemplified above are used alone or in admixture of two or more so as to have an absorption wavelength in a desired region. Among the above-exemplified charge generating agents, in particular, a laser beam printer using a light source such as a semiconductor laser or an image forming apparatus of a digital optical system such as a facsimile requires a photoreceptor having sensitivity in a wavelength region of 700 nm or more. Therefore, for example, phthalocyanine pigments such as metal-free phthalocyanine and titanyl phthalocyanine are preferably used.

  On the other hand, an analog optical image forming apparatus such as an electrostatic copying machine using a white light source such as a halogen lamp requires a photosensitive member having sensitivity in the visible region, so that a perylene pigment or a bisazo pigment is preferable. Used for.

  As the resin binder for the charge generation layer, various resin binders conventionally used in the photosensitive layer can be used. For example, polyvinyl acetal resin, polyvinyl butyral resin, vinyl chloride resin, vinyl acetate resin, silicone resin, polycarbonate resin, polyester resin, polyethylene, polypropylene, polystyrene, acrylic resin, polyurethane resin, epoxy resin, melamine resin, polyamide resin, polystyrene resin Polyacetal resins, polyarylate resins, polysulfone resins, methacrylic acid ester polymers, copolymers thereof, and the like can be used in appropriate combinations.

  The charge transport layer is a coating film made of a material in which a charge transport agent is dispersed in a resin binder. The charge transport layer retains the charge of the photoconductor as an insulator layer in the dark, and the charge injected from the charge generation layer during light reception. Demonstrate the function to transport.

  Examples of the charge transport agent include a hydrazone compound, a pyrazoline compound, a pyrazolone compound, an oxadiazole compound, an oxazole compound, an arylamine compound, a benzidine compound, a stilbene compound, a styryl compound, polyvinyl carbazole, a polysilane, or a hole transport agent such as an anhydrous succinate. Acid, maleic anhydride, dibromosuccinic anhydride, phthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, pyromellitic anhydride, pyromellitic acid, trimellitic acid, trimellitic anhydride, phthalimide, 4 -Electrons such as nitrophthalimide, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromanyl, o-nitrobenzoic acid, trinitrofluorenone, quinone, diphenoquinone, naphthoquinone, anthraquinone, stilbenequinone It is possible to use the Okuzai. For example, compounds having structural formulas represented by (A-1) to (A-15) below are used, but the present invention is not limited thereto.

  As the resin binder for the charge transport layer, various resin binders conventionally used in the photosensitive layer can be used. For example, polycarbonate resin, polyester resin, polyvinyl acetal resin, polyvinyl butyral resin, vinyl chloride resin, vinyl acetate resin, polyethylene, polypropylene, polystyrene, acrylic resin, polyurethane resin, epoxy resin, melamine resin, silicone resin, polyamide resin, polystyrene resin Polyacetal resins, polyarylate resins, polysulfone resins, methacrylic acid ester polymers, copolymers thereof, and the like can be used in appropriate combinations. In particular, polycarbonate resins and polyester resins having one or more of the structural units (B-1) to (B-3) shown below are suitable.

  In addition to the above components, these photosensitive layers may contain various known additives as long as the electrophotographic characteristics are not adversely affected. Specifically, antioxidants, radical scavengers, singlet quenchers, UV absorbers and other deterioration inhibitors, softeners, plasticizers, surface modifiers, dispersion stabilizers, waxes, acceptors, donors, etc. can do. In order to improve the sensitivity of the photosensitive layer, for example, known sensitizers such as terphenyl, halonaphthoquinones, acenaphthylene and the like may be used in combination with the charge generator.

  The protective layer 4 is provided for the purpose of improving the printing durability and can be provided as necessary, and is composed of a layer mainly composed of a resin binder or an inorganic thin film such as amorphous carbon. In resin binders, silicon oxide (silica), titanium oxide, zinc oxide, calcium oxide, aluminum oxide (alumina), zirconium oxide are used for the purpose of improving conductivity, reducing friction coefficient, and imparting lubricity. Metal oxides such as barium sulfate and calcium sulfate, metal nitrides such as silicon nitride and aluminum nitride, metal oxide fine particles, or fluorine resin particles such as tetrafluoroethylene resin, fluorine comb type A graft polymerization resin or the like may be contained. In addition, for the purpose of imparting charge transportability, a charge transport material, an electron accepting material and a novel fluorenone compound of the present invention used in the photosensitive layer can be contained.

  Next, a method for producing the electrophotographic photoreceptor of the present invention will be described. The single-layer type photoreceptor in the present invention comprises a fluorenone compound (electron transport agent) represented by the general formula (1), a charge generator, a resin binder, and, if necessary, a hole transport agent as a suitable solvent or solvent. It is formed by dissolving or dispersing in, coating the obtained coating solution on a conductive substrate and drying.

  In the single layer type photoreceptor, the charge generating agent may be blended in an amount of 0.1 to 50 parts by weight, preferably 0.5 to 30 parts by weight with respect to 100 parts by weight of the resin binder. What is necessary is just to mix | blend an electron carrying agent in the ratio of 5-150 weight part with respect to 100 weight part of resin binders, Preferably it is 10-100 weight part. Moreover, what is necessary is just to mix | blend a hole transport agent in the ratio of 5-500 weight part with respect to 100 weight part of resin binders, Preferably it is 25-200 weight part. In addition, when using together an electron transport agent and a hole transport agent, the total amount of an electron transport agent and a hole transport agent is 20-500 weight part with respect to 100 weight part of resin binders, Preferably it is 30-200 weight. The part is appropriate.

  In order to maintain a practically effective surface potential, the thickness of the photosensitive layer in the single-layer type photoreceptor is preferably in the range of 5 to 80 μm, more preferably 10 to 50 μm.

  In the multilayer photoreceptor of the present invention, a charge generation layer containing a charge generation agent is first formed on a conductive substrate by means such as vapor deposition or coating, and then the general formula (1) is formed on the charge generation layer. It is produced by applying a coating solution containing a fluorenone compound (electron transport agent) represented by the formula (I) and a resin binder, and drying to form a charge transport layer.

  In the laminated photoconductor, the charge generating agent and the resin binder constituting the charge generating layer can be used in various ratios, but the charge generating agent is 5 to 1000 parts by weight with respect to 100 parts by weight of the resin binder. It is preferable to add 30 to 500 parts by weight. In the case where a hole transport agent is contained in the charge generation layer, the ratio of the hole transport agent is 10 to 500 parts by weight, preferably 50 to 200 parts by weight with respect to 100 parts by weight of the binder resin. .

  The electron transporting agent and the resin binder constituting the charge transporting layer can be used in various proportions within a range that does not inhibit the transport of charges and a range that does not crystallize. It is appropriate to blend the electron transport agent in an amount of 10 to 500 parts by weight, preferably 25 to 200 resins with respect to 100 parts by weight of the resin binder so that it can be easily transported. When the charge transport layer contains another electron transport agent having a predetermined oxidation-reduction potential, the proportion of the other electron transport agent is 0.1 to 40 parts by weight, preferably 100 parts by weight of the binder resin. Is suitably 0.5 to 20 parts by weight.

  The thickness of the photosensitive layer in the multilayer photoreceptor is about 0.01 to 5 μm, preferably about 0.1 to 3 μm for the charge generation layer, and about 5 to 80 μm, preferably about 10 to 50 μm for the charge transport layer. . In a single layer type photoreceptor, between a conductive substrate and a photosensitive layer, and in a laminated type photoreceptor, between a conductive substrate and a charge generation layer, between a conductive substrate and a charge transport layer, or a charge. A barrier layer may be formed between the generation layer and the charge transport layer in a range that does not impair the characteristics of the photoreceptor. Further, a protective layer may be formed on the surface of the photoreceptor.

  When the photosensitive layer is formed by a coating method, the charge generator, charge transport agent, resin binder and the like exemplified above together with a suitable solvent, a known method such as a roll mill, ball mill, attritor, paint shaker or ultrasonic wave A dispersion liquid may be prepared by dispersing and mixing using a disperser or the like, and this may be applied and dried by a known means.

  As the solvent for preparing the dispersion, various organic solvents can be used, for example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; benzene , Aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether; acetone, Ketones such as methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformaldehyde, dimethylformamide, dimethyl sulfoxide, etc. It is below. These solvents are used alone or in admixture of two or more.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

Synthesis of specific exemplary compound (1)

A reactor charged with 2.5 g (0.0074 mol) of 2,7-dibromo-9-fluorenone, 5.0 g of F—C ₆ H ₄ SCu, and 100 ml of DMF was heated and reacted at 130 to 140 ° C. for 19 hours. After cooling, filtration was performed to remove insolubles, extraction was performed by adding toluene / water, and drying was performed using Na ₂ SO ₄ . The filtrate was concentrated to give 3.70 g of a dark brown solid.

The obtained solid was subjected to column chromatography to obtain 2.64 g of an orange solid. This was recrystallized from 90 ml of IPA to obtain orange thin crystals. Yield: 2.25 g. Liquid chroma purity: 96.7%. Yield: 68.0%
2,7-bis (p-fluorophenylthio) -9-fluorenone 0.7 g (96.7% / 0.0016 mol), malononitrile 0.231 g (0.0035 mol), dehydrated methanol 10 ml, and piperidine 4 drops were charged. The reactor was reacted under reflux for 5 hours. After cooling, methanol was added and filtration was performed to obtain 0.73 g of a dark green solid. The obtained solid was recrystallized to obtain purple crystals. As a result of mass spectrometry by FD-MS, it was confirmed to be the target product. Yield: 0.54g. Liquid chroma purity: 93.8%. Yield: 65.9%. Melting point: 231.0 ° C.

Synthesis of specific exemplary compound (4)

A reactor charged with 2,7-dibromo-9-fluorenone 2.0 g (0.0059 mol), CH ₃ -C ₆ H ₄ SCu 8.0 g, and DMF 80 ml was heated at 130 to 150 ° C. for 9 hours. After cooling, filtration was performed to remove insolubles, extraction was performed by adding toluene / water, and drying was performed using Na ₂ SO ₄ . The filtrate was concentrated to give 3.45 g of a brown liquid.

  The resulting liquid was subjected to column chromatography using toluene / hexane = 5/5 as a developing solvent to obtain 2.18 g of an orange solid. Liquid chroma purity: 86.4%. Yield: 75.2%.

2,7-bis (m-methylphenylthio) -9-fluorenone 2.18 g (86.4% / 0.0044 mol), malononitrile 0.58 g (0.0088 mol), dehydrated methanol 30 ml, piperidine 12 drops were charged. The reactor was reacted under reflux for 3 hours. After cooling, methanol was added and filtration was performed to obtain a solid. The obtained solid was recrystallized (twice) to obtain black crystals. As a result of mass spectrometry by FD-MS, it was confirmed to be the target product. Yield: 1.01 g. Liquid chroma purity: 94.9%. Yield: 46.1%. Melting point: 140.5 ° C.

Preparation and evaluation of single layer type electrophotographic photoreceptor << Preparation of single layer type electrophotographic photoreceptor >>
The α-type TiO2 phthalocyanine as the charge generating agent, the exemplified compound (A-8) as the hole transporting agent, and the exemplified compound (25) as the electron transporting agent are selected and blended together with the resin binder and the solvent in the proportions shown below, and 50 Mix and disperse for hours.

(Ingredients) (Parts by weight)
Charge generator 5
Hole transport agent 50
Electron transfer agent 30
Resin binder (polycarbonate) 100
Solvent (tetrahydrofuran) 800

  This dispersion was coated on the surface of a 30 mm diameter aluminum drum (conductive substrate) having a mirror-finished surface by a dip coating method and dried to produce a single layer type electrophotographic photosensitive member.

<Evaluation of single-layer electrophotographic photoreceptor>
In order to verify the practicality of the obtained electrophotographic photosensitive member, it is mounted on a commercially available laser printer (Brother Industries, Ltd. HL-730) using a positively charged electrophotographic photosensitive member, and a normal temperature and humidity environment (20 Image quality and durability were evaluated by visual observation on a print sample after continuous printing of 5000 sheets in the A4 lateral direction under 50 ° C HR). The results are summarized in Table 1.

<< Creation and evaluation of organic electrophotographic photoreceptor >>
A photoconductor was prepared in the same manner as in Example 3 except that the electron transporting material (Exemplary Compound (25)) used in Example 3 was replaced with the fluorenone compound shown by Exemplary Compound (38). The photoreceptor was evaluated. The results are summarized in Table 1.

[Comparative Example 1]
<< Creation and evaluation of organic electrophotographic photoreceptor >>
A photoconductor was prepared in the same manner as in Example 3 except that the electron transport material (Exemplary Compound (25)) used in Example 3 was replaced with a diphenoquinone compound (manufactured by Tokyo Chemical Industry Co., Ltd.) represented by the following formula (a). The photoreceptor was prepared and evaluated in the same manner as in Example 3. The results are summarized in Table 1.

（ａ）

(A)

Preparation and evaluation of multilayer electrophotographic photoreceptor << Preparation of multilayer electrophotographic photoreceptor >>
100 parts by weight of α-type TiO ₂ phthalocyanine as a charge generating agent, 100 parts by weight of polyvinyl butyral as a resin binder, and 2000 parts by weight of a solvent (tetrahydrofuran) were mixed and dispersed in a ball mill for 50 hours to prepare a coating solution for a charge generating layer. This coating solution was applied to the surface of an aluminum substrate, which is a conductive base material, by dip coating, and dried in hot air at 100 ° C. for 60 minutes to form a charge generation layer.

Next, 100 parts by weight of exemplary compound (4) as an electron transport material agent, 100 parts by weight of polycarbonate as a resin binder, and 800 parts by weight of a solvent (toluene) were mixed and dispersed in a ball mill for 50 hours to prepare a coating solution for a charge transport layer. . Then, this coating solution was applied onto the charge generation layer by a dip coating method, and dried with hot air at 100 ° C. for 60 minutes to form a charge transport layer, whereby a multilayer electrophotographic photoreceptor was produced.
<< Evaluation of Laminated Electrophotographic Photoconductor >>
In order to verify the practicality of the obtained electrophotographic photosensitive member, it is mounted on a commercially available laser printer (Brother Industries, Ltd. HL-730) using a positively charged electrophotographic photosensitive member, and a normal temperature and humidity environment (20 Image quality and durability were evaluated by visual observation on a print sample after continuous printing of 5000 sheets in the A4 lateral direction under 50 ° C HR). The results are summarized in Table 2.

[Comparative Example 2]
<< Creation and evaluation of organic electrophotographic photoreceptor >>
Photosensitive as in Example 5, except that the electron transfer agent (Exemplary Compound (4)) used in Example 5 was replaced with a compound represented by the following formula (b) (4H-thiopyran-1,1-dioxide derivative). The photoconductor was evaluated in the same manner as in Example 5. The results are summarized in Table 2.

（ｂ）

(B)

The novel fluorenone compound obtained by the present invention has excellent electron transport properties, and when the compound is used in an electrophotographic photoreceptor, the dispersibility in the resin is improved, and the electrical properties and repeat stability are also excellent. A durable electrophotographic photoreceptor is obtained.

1 is a schematic cross-sectional view of an electrophotographic photoreceptor according to the present invention.

Explanation of symbols

1: Conductive substrate 2: Undercoat layer 3: Photosensitive layer 4: Protective layer

Claims (3)

A fluorenone derivative represented by the following formula (1).

... (1)
[Wherein X represents = O or = C (CN) ₂ ;
R _{1 to} R ₈ are each independently a hydrogen atom, a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted alkyl group, substituted or unsubstituted Represents a group selected from the group consisting of an alkyloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted aralkyl group, and a substituted or unsubstituted alkoxycarbonyl group, any one of which is substituted or unsubstituted An arylthio group or a halogenated aryl group. ]   An electrophotographic photoreceptor having a photosensitive layer on a conductive substrate, wherein the photosensitive layer contains the compound according to claim 1.   An electrophotographic apparatus comprising the electrophotographic photosensitive member according to claim 2.

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