JPH10212420A - Fluorenone derivative and electrophotographic receptor produced by using the derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject new compound giving an electrophotographic receptor having high sensitivity and high durability and useful for laser printer, shutter printer, etc., by introducing a specific bisazo structure into a fluorenone. SOLUTION: This compound is expressed by formula I R<1> is a halogen, nitro, OH, a (substituted) alkyl, etc.; K<1> and K<2> are each a coupler residue containing OH having coupling potency; (m) is 0-4}, e.g. 2- 2-[4-( 3-[N-(2- chlorophenyl)carbamoyl]-2-hydroxyl-1-naphthyl}azo)phenyl]vinyl}-7- 3-[N-(2- chlorophenyl)carbamoyl]-2-hydroxyl-1-naphthyl}azofluorenone. The compound of the formula I can be produced by tetrazotizing a compound of the formula II by conventional method and coupling the product with a corresponding coupler.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrophotographic photosensitive member. More specifically, the present invention relates to a highly sensitive electrophotographic photoreceptor containing a novel bisazo compound having a fluorenone structure.

[0002]

2. Description of the Related Art As an electrophotographic photoconductor, a photoconductor using an inorganic photoconductive substance such as selenium, cadmium sulfide, or zinc oxide has been used. Organic photoconductive compound (hereinafter referred to as OPC) having many advantages such as easy handling, good image quality, and easy to obtain photoconductors of various shapes such as drums, sheets and belts. The so-called OPC photoreceptor using OPC photoreceptors has been adopted for plain paper copiers and printers, and its ratio is increasing year by year.

[0003]

The OPC photoreceptor has many advantages over the conventional inorganic photoreceptor, but is inferior in sensitivity, durability and the like. It is used in the machine field. Therefore, development of OPC having excellent sensitivity and durability is desired. An object of the present invention is to provide a new OPC having such performance and a photoconductor using the same.

[0004]

Means for Solving the Problems The present inventors have proposed a novel OP for obtaining a highly sensitive and highly durable electrophotographic photosensitive member.
As a result of intensive studies on C, the present inventors have found that a novel bisazo compound having a specific fluorenone structure is suitable, and have reached the present invention. That is, the gist of the present invention is represented by the following general formula (I)

[0005]

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Wherein R ¹ is a halogen atom, a nitro group,
A hydroxyl group, an optionally substituted alkyl group, an aralkyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an arylcarbonyl group, an alkyloxycarbonyl group, a substituted amino group, a thioether group or a heterocyclic group, Represents an integer of 0 to 4. K ¹ and K ² represent a coupler residue containing a hydroxyl group having a coupling ability. ) And an electrophotographic photosensitive member having a photosensitive layer containing the fluorenone derivative.

Hereinafter, the present invention will be described in detail. The bisazo compound having a fluorenone structure contained in the electrophotographic photoreceptor of the present invention has a structure represented by the general formula (I). In the general formula (I), R ¹ is a halogen atom such as a chlorine atom or a bromine atom; a nitro group; a hydroxyl group; or an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a decyl group; an allyl group; Aralkyl groups such as phenyl group and naphthyl group; alkoxy groups such as methoxy group; aryloxy groups such as phenoxy group; acyl groups such as acetyl group; arylcarbonyl groups such as phenylcarbonyl group; Alkyloxycarbonyl group; substituted amino group such as methylamino group, phenylamino group, diethylamino group; thioether group such as methylmercapto group; and organic residue such as heterocyclic residue such as pyridyl group and thiophenyl group. And these organic residues may have a substituent. Among them, R ¹ is preferably a halogen atom, an alkyl group, or an aryl group. m represents an integer of 0 to 4, and m = 0 is particularly preferable. K ¹ and K ² are each a coupler residue containing a hydroxyl group having a coupling ability, and examples thereof include groups represented by the following general formulas (II) to (VI). In addition, the hydroxyl group having a coupling ability means a hydroxyl group which imparts a property capable of coupling with a diazonium salt to an aromatic ring or the like to which the hydroxyl group is bonded.

[0008]

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In the general formula (II), Y is bonded to a benzene ring to form a naphthalene ring, an anthracene ring, a carbazole ring,
R represents a residue required to form a polycyclic aromatic ring or a hetero ring such as a benzocarbazole ring, a dibenzofuran ring, a benzonaphthofuran ring, or a diphenylene sulfide ring;
² and R ³ are each independently a hydrogen atom; an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group which may have a substituent; a benzyl group which may have a substituent Aralkyl groups such as phenethyl group and naphthylmethyl group; aryl groups such as phenyl group, diphenyl group and naphthyl group which may have a substituent; carbazole group, dibenzofuran group, benzimidazolone group, benzthiazole group and thiazole A heterocyclic group such as a pyridine group or a pyridine group; or a cyclic amino group together with a nitrogen atom to which R ² and R ³ are bonded. R ² and R ³ may be the same or different groups, but from the viewpoint of sensitivity, it is preferable that one is a hydrogen atom and the other is a group other than a hydrogen atom. Z represents an oxygen atom or a sulfur atom, and an oxygen atom is particularly preferred. n represents 0, 1, or 2, and 0 or 1 is preferable.

[0010]

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In the general formulas (III) and (IV), R ⁴
Represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group, an aryl group, and a heterocyclic group, which are represented by the same examples as R ² and R ³ .

[0012]

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In the general formulas (Va, b) and (VI-a, b), W represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring. Examples of the divalent aromatic hydrocarbon group include a divalent group of a monocyclic aromatic hydrocarbon such as an o-phenylene group; an o-naphthylene group, a peri-naphthylene group, a 1,2-anthraquinonylene group; 9,10
A divalent group of a condensed polycyclic aromatic hydrocarbon such as a phenanthrylene group;

The divalent heterocyclic group containing a nitrogen atom in the ring includes, for example, a 3,4-pyrazoldiyl group,
A nitrogen atom such as a 2,3-pyridinediyl group, a 4,5-pyrimidinediyl group, a 6,7-indazolediyl group, a 5,6-benzimidazolediyl group, a 6,7-quinolinediyl group, and preferably 2 or less And a 5- to 10-membered heterocyclic divalent group containing a nitrogen atom in the ring. In consideration of sensitivity and durability, W is an o-phenylene group,
o-naphthylene group, peri-naphthylene group, 2,3-
A pyridinediyl group and a 4,5-pyrimidindiyl group are preferable, and an o-phenylene group and an o-naphthylene group are particularly preferable.

In the present invention, the divalent group of these aromatic hydrocarbons represented by W, the divalent group of a heterocyclic ring containing a nitrogen atom in the ring, and the like may have a substituent. Examples of such a substituent include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and n
Alkyl groups such as hexyl group; alkoxy groups such as methoxy group, ethoxy group, propoxy group and butoxy group; hydroxyl group; nitro group; cyano group; amino group; substitution such as dimethylamino group, diethylamino group and dibenzylamino group. Amino group; halogen atom such as fluorine atom, chlorine atom, bromine atom and iodine atom; carboxyl group; alkoxycarbonyl group such as ethoxycarbonyl group; carbamoyl group;
An aryloxy group such as a phenoxy group; an arylalkoxy group such as a benzyloxy group; an aryloxycarbonyl group such as a phenyloxycarbonyl group. Among them, an alkyl group, an alkoxy group, a nitro group, a halogen atom, a hydroxyl group, and a carboxyl group are preferable, and a methyl group, a methoxy group, a nitro group, a chlorine atom, a hydroxyl group, and the like are particularly preferable.

The compound having a group of the formula (Va) is often present as a mixture with an isomer having a group of the formula (Vb). Groups of type Va- and formula (Vb) are treated as the same group. Similarly, for the group of the formula (VI-a), (VI-a)
-B) Treated as the same group as the type group. The bisazo compound represented by the general formula (I) is, for example, a compound represented by the following general formula (VII)

[0017]

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(Wherein R ¹ and m have the same meanings as in the above formula (I)), and can be easily synthesized by tetrazotizing a diamine represented by the general formula and coupling with a corresponding coupler. Such a coupling reaction is carried out according to a known method, usually using water / or dimethylformamide,
Reaction temperature 30 ° C in organic solvent such as dimethyl sulfoxide
The reaction may be performed for about 1 to 10 hours in the following.

When the coupler residues K ¹ and K ² are made to be different groups, two kinds of couplers may be mixed and used. Note that two different couplers, for example, k,
If the coupling reaction is carried out by selecting appropriate reaction conditions using k ', a mixture of two isomers of the following (a) and (b) can be obtained with high purity, and at the same time, K ¹ = K ² = k Of compound (c) and compound (d) of K ¹ = K ² = k ′.

[0020]

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The aromatic diamine represented by the general formula (VII) is produced, for example, by reducing a corresponding dinitro compound represented by the following general formula (VIII).

[0022]

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(Wherein R ¹ and m have the same meanings as in the above formula (I)). The reduction reaction is suitably carried out under known reduction reaction conditions such as iron powder / hydrochloric acid and stannous chloride / hydrochloric acid. General formula (VIII)
Are produced, for example, according to the following reaction formula. In the reaction formula, R ¹ and m have the same meanings as in the general formula (I). A diazonium salt (IX-b) is obtained by diazotizing a nitroaminofluorenone represented by the following general formula (IX-a).
To manufacture. Next, the diazonium salt (IX-b) and nitrostyrene (IX-c) are coupled in the presence of a palladium catalyst to obtain the dinitro compound represented by the general formula (VIII).

[0024]

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Representative examples of the fluorenone derivative of the general formula (I) useful as an electrophotographic photoreceptor are shown in Table 1 below, but the present invention is not limited to these compounds. In Table -1, if K ¹ and K ² are different or if isomer mixtures, the compounds of formula (I),
A single compound and those containing the above-mentioned various mixtures are also meant.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3]

[0029]

[Table 4]

[0030]

[Table 5]

The electrophotographic photoreceptor of the present invention has a photosensitive layer containing one or more bisazo compounds represented by the above general formula (I). The photosensitive layer is well known in various forms, but in the photosensitive member of the present invention, any of these types may be used. Particularly preferred is a layered photoreceptor in which the bisazo compound of the present invention is dispersed in a binder as a charge generating material, which is used as a charge generating layer, and which includes a well-known charge transporting material. A single-layer type photoconductor in which a well-known charge transporting material is added in a dispersion layer of a bisazo-based compound may be used.

The bisazo compound of the present invention represented by the above general formula (I) has a high charge carrier generation efficiency and a high carrier injection efficiency to the charge transporting material, and is a laminated type or single layer type function-separated type photoreceptor. Has extremely excellent performance as a charge generation material. The charge transporting material used in combination with the bisazo compound of the present invention is generally classified into two types, an electron transporting medium and a hole transporting medium. Both can be used for the photoreceptor of the present invention, and a mixture thereof Can also be used. As an electron transport medium, an electron-withdrawing compound having an electron-withdrawing group such as a nitro group, a cyano group, and an ester group, for example, 2,4,7-trinitrofluorenone,
Examples include nitrated fluorenone such as 2,4,5,7-tetranitrofluorenone or tetracyanodimethane. Further, as a hole transport medium, an electron-donating organic photoconductive compound such as carbazole, indole,
Heterocyclic compounds such as imidazole, oxazole, thiazole, oxadiazole, pyrazole, pyrazoline, thiadiazole; triarylalkane derivatives such as triphenylmethane; triarylamine derivatives such as triphenylamine; phenylenediamine derivatives; N-phenylcarbazole derivatives Stilbene derivatives; hydrazone compounds, etc., particularly, substituted amino groups such as dialkylamino groups and diphenylamino groups, or electron-donating groups such as alkoxy groups and alkyl groups, or those substituted with these electron-donating groups. Compounds having a large electron donating property substituted by the substituted aromatic ring group. Further, a polymer having a group consisting of these compounds in a main chain or a side chain, such as polyvinylcarbazole, may also be used. Suitable compounds to be combined with the azo compound of the present invention include compounds as shown in Table 2 below.

[0033]

[Table 6]

[0034]

[Table 7]

[0035]

[Table 8]

[0036]

[Table 9]

[0037]

[Table 10]

[0038]

[Table 11]

[0039]

[Table 12]

[0040]

[Table 13]

The electrophotographic photoreceptor of the present invention can be manufactured according to a conventional method. That is, the electrophotographic photoreceptor of the present invention comprises:
On a conductive support, a laminate type having a charge generation layer and a charge transport layer containing the bisazo compound of the present invention, or a single layer type photosensitive member having a photosensitive layer in which a bisazo compound is dispersed, In addition, an intermediate layer such as an adhesive layer and a blocking layer, and a layer for improving performance such as electric characteristics and mechanical characteristics such as a protective layer may be provided. As the conductive support, any of those used in known electrophotographic photoreceptors can be used. Specific examples include metal drums and sheets of aluminum, copper, and the like, and laminates and vapor-deposits of these metal foils. Further, plastic films, plastic drums, paper, and the like, which are subjected to conductive treatment by applying a conductive substance such as metal powder, carbon black, copper iodide, and polymer electrolyte together with a suitable binder, may be used.
In addition, a conductive plastic sheet or drum containing a conductive substance such as metal powder, carbon black, or carbon fiber, or a plastic film having a conductive metal oxide layer such as tin oxide or indium oxide on its surface. And the like.

In the above-mentioned laminated photoreceptor, a charge generation layer is usually formed on a conductive support, and a charge transport layer is formed thereon, but the structure may be reversed. The charge generation layer is formed by applying and drying a coating solution containing the bisazo compound of the present invention and a binder polymer. The coating solution may have a bisazo compound dissolved therein, but is usually used in a dispersed state. Butylamine as a solvent for preparing a coating solution,
Basic solvents such as ethylenediamine; ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene and xylene; N, N-dimethylformamide, acetonitrile and N-methylpyrrolidone And aprotic polar solvents such as dimethyl sulfoxide; alcohols such as methanol, ethanol, and isopropanol;
Esters such as ethyl acetate, methyl formate and methyl cellosolve acetate; and chlorinated hydrocarbons such as dichloroethane and chloroform.

When dispersing the bisazo compound in the coating solution, it is necessary that the particle size be 1 μm or less, preferably 0.5 μm or less. As the binder, styrene, vinyl acetate, acrylic acid ester, methacrylic acid ester, vinyl alcohol, polymers and copolymers of vinyl compounds such as ethyl vinyl ether, phenoxy resin,
Examples thereof include polysulfone, polyvinyl acetal, polycarbonate, polyester, polyamide, polyurethane, cellulose ester, cellulose ether, epoxy resin, and silicon resin.

The ratio of the bisazo compound to the binder polymer of the present invention is not particularly limited, but is generally 5 to 500 parts by weight, preferably 20 to 300 parts by weight, per 100 parts by weight of the bisazo compound. Use In addition to the above coating liquid, a dispersion stabilizer,
You may add a coating property improving agent, and also a dye, an electron-withdrawing compound, and other additives for improving performance. The thickness of the charge generation layer is 0.05 to 5 μm, preferably 0.1 to 2 μm.
μm.

One or more kinds of the above-mentioned charge transporting materials are dissolved in the above-mentioned coating solution for the charge generating layer, and the film thickness after drying is 5 to 5%.
A single-layer type photoreceptor can be obtained by applying it on a conductive support so that the thickness becomes 0 μm, preferably 10 to 30 μm. The ratio of the bisazo compound to the binder polymer and the charge transport material is usually 10 to 1000 parts by weight, preferably 3 to 10 parts by weight, per 10 parts by weight of the bisazo compound.
0 to 500 parts by weight, and the charge transporting material is 5 to 1000 parts by weight, preferably 20 to 500 parts by weight.

In the laminate type photoreceptor, a charge transport layer is formed on the charge generation layer by applying a coating solution containing an electric transport material and drying. When the charge transporting material is a polymer compound having a film forming property, a binder polymer may not be particularly used, but may be mixed for improving flexibility and the like. In the case of a low molecular compound, a binder polymer is used for forming a film. The above-mentioned binder polymer is used, and the amount thereof is generally in the range of 50 to 3000 parts by weight, preferably 70 to 1000 parts by weight, per 100 parts by weight of the charge transporting material. The charge transport layer has a thickness of 5 to 70 μm, preferably 10 to 50 μm.

In addition to the above, various additives can be used in the charge transport layer in order to improve the performance and the mechanical strength and durability of the coating film. Examples of such additives include electron-withdrawing compounds and dyes, stabilizers such as ultraviolet absorbers and antioxidants, coatability improvers, plasticizers, and crosslinking agents.
Examples of the electron-withdrawing compound include chloranil, 2,3-
Dichloro-1,4-naphthoquinone, 2-methylanthraquinone, 1-nitroanthraquinone, 1-chloro-5-
Quinones such as nitroanthraquinone, 2-chloroanthraquinone and phenanthrenequinone; aldehydes such as 4-nitrobenzaldehyde; 9-benzoylanthracene, indandione, 3,5-dinitrobenzophenone, 3,3 ', 5,5'-tetra Ketones such as nitrobenzophenone; acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; tetracyanoethylene, terephthalmalononitrile, 4-nitrobenzalmalononitrile,
4-benzoyloxybenzalmalononitrile, 4-
Cyano compounds such as (p-nitrobenzoyloxy) benzalmalononitrile; 3-benzalphthalide, 3- (α
-Cyano-p-nitrobenzal) phthalide, 3- (α-
Phthalides such as (cyano-p-nitrobenzal) -4,5,6,7-tetrachlorophthalide.

[0048]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In the examples, “parts” means “parts by weight”. Example 1 Synthesis of fluorenone derivative 4.0 g of 2-amino-7-nitro-9-fluorenone was added to 150 ml of water and 50 ml of concentrated hydrochloric acid, cooled, and 15 ml of a 10% aqueous solution of sodium nitrite was added dropwise at 5 ° C. or lower. Then, the mixture was stirred at 5 ° C. or lower for 1 hour for diazotization. To the diazotized solution was added 7.0 g of 42% borofluoric acid,
After stirring at 5 ° C. or lower, the precipitated crystals were collected by filtration, washed sequentially with a small amount of cold water and cold methanol, and dried to obtain 4.2 g of a diazonium salt.

Next, a solution consisting of 4.2 g of p-nitrostyrene, 3.4 g of sodium acetate, 0.57 g of palladium (0) bisdibenzylideneacetone and 65 ml of acetonitrile was stirred at room temperature under nitrogen, and the diazonium salt was added thereto. After adding 4.2 g, the mixture is stirred for 1.5 hours. The resulting solid was collected by filtration, washed with methanol and water, and dried to obtain 4.6 g of a dinitro compound (i). This compound has a molecular weight of 372.33 as a molecular formula C ₂₁ H ₁₂ N ₂ O ₅ ,
A peak at M / e = 372 was confirmed in the mass spectrum.

4.6 g of the dinitro compound (i) was reduced with an iron / hydrochloric acid system, and purified by an alumina column.
2 g were obtained. This compound has a molecular weight of 312.37 as a molecular formula C ₂₁ H ₁₆ N ₂ O ₁ , and M
A peak at / e = 312 was confirmed. The disappearance of the absorption of the nitro group was confirmed by the infrared absorption spectrum (FIG. 1). Elemental analysis values were as follows. C ₂₁ H ₁₆ N ₂ O ₁ Calculated (%) C: 80.75 H: 9.30 N: 8.97 measurements (%) C: 80.33 H: 8.91 N: 8.76

0.6 g of diamine (ii) was added to 30 ml of water and 4 ml of concentrated hydrochloric acid, and cooled.
An aqueous solution of sodium nitrite (3.0 ml) was added dropwise, and the mixture was stirred at 5 ° C. or lower for 1 hour for tetrazotization. Next, 1.6 g of 42% borofluoric acid was added, and the mixture was stirred at 5 ° C. or lower.
The precipitated crystals were collected by filtration, washed sequentially with a small amount of cold water and cold methanol, and dried to obtain 0.9 g of a tetrazonium salt. 0.33 g of the tetrazonium salt was added to dimethyl sulfoxide 10
of a coupler 0.43 having the following structure.
g in 50 ml of dimethyl sulfoxide

[0052]

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After adding 1.2 g of a 30% aqueous sodium acetate solution to the reaction system, the mixture was stirred for 3 hours.
The precipitated crystals were collected by filtration. This was washed with diluted acetic acid, water and tetrahydrofuran, and then dried to obtain a solid (iii).
Has a black-purple color. Based on the following elemental analysis values and the infrared absorption spectrum shown in FIG.
It was identified as 1 bisazo compound. Yield 0.33g
And the elemental analysis values were as follows. C ₅₅ H ₃₄ Cl ₂ N ₆ O ₅ Calculated value (%) C: 71.05 H: 3.69 N: 9.04 Cl: 7.63 Measured value (%) C: 70.36 H: 3. 19 N: 8.68 Cl: 7.55

Example 2 The bisazo compound of Example 1 and a table synthesized in the same manner
No. 1 0.4 parts of each of the 2 to 7 bisazo compounds was dispersed together with 30 parts of 4-methyl-4-methoxypentanone-2 by a sand grinder, and polyvinyl butyral (trade name: BH-3, manufactured by Sekisui Chemical Co., Ltd.) )
0.4 part was added and dissolved. The obtained dispersion liquid of the bisazo compound was applied on a 75 μm-thick polyester film deposited on an aluminum vapor-deposited layer using a wire bar and dried to a dry film thickness of 0.4 g / m ² . 4,4′-bis {N- [4- (α)
-Styryl) phenyl] -N-phenylamino diphenoxymethane and 110 parts of a polycarbonate resin (manufactured by Mitsubishi Chemical Corporation, Novarex 7025) dissolved in 670 parts of tetrahydrofuran have a dry film thickness of 28 μm. To form a charge generation layer. Thus, an electrophotographic photosensitive member having a two-layer photosensitive layer was obtained.

As the sensitivity of these photosensitive members, the value of the half-life exposure amount (E1 / 2) was measured, and the results are shown in Table 3. The half-exposure amount was measured on the photoreceptor using an electrostatic copying paper test apparatus (Kawaguchi Denki Seisakusho model SP-428). First, it is charged by corona discharge at -6.5 kV in a dark place, and the charged voltage (V) at that time is then charged into the sensitivity (E1 / 2 (lux · s).
As ec)), exposure was performed with white light having an illuminance of 1 lux, and an exposure amount necessary for the surface potential to attenuate to half of the initial surface potential was determined.

[0056]

[Table 14] *: Compound No. in Table 1. Corresponding to

[0057]

The photoreceptor for electrophotography containing the bisazo compound of the present invention has high sensitivity and good color sensitivity, and particularly has little light fatigue. It has little fluctuation in potential, high stability, and extremely excellent durability. Not only electrophotographic plain paper copiers, but also laser printers, liquid crystals, shutter printers, and LEDs that require particularly stable and reliable performance
It is a photoconductor suitable for a photoconductor for a printer such as a printer.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of diamine (ii) obtained in Example 1.

FIG. 2 is an infrared absorption spectrum of the bisazo compound (iii) obtained in Example 1.

Claims (6)

[Claims] 1. A fluorenone derivative represented by the following general formula (I). Embedded image (Wherein, R ¹ represents a halogen atom, a nitro group, a hydroxyl group, an optionally substituted alkyl group, an aralkyl group, an aryl group, an alkoxy group, an aryloxy group, an acyl group, an arylcarbonyl group, an alkyloxycarbonyl group, Represents an amino group, a thioether group or a heterocyclic group;
Represents an integer of from 4 to 4. K ¹ and K ² represent a coupler residue containing a hydroxyl group having a coupling ability. ) 2. K ¹ and / or K ² in the general formula (I)
Has the general formulas (II) to (VIb): Embedded image (Wherein Y represents a residue forming a condensed ring with a benzene ring, and R ² , R ³ and R ⁴ each independently represent a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group Or an aryl group or a heterocyclic group, or R ² and R ³ may form a cyclic amino group together with the nitrogen atom to which they are bonded.
Z represents an oxygen atom or a sulfur atom. n is 0, 1 or 2
Is shown. W represents a divalent aromatic hydrocarbon group or a divalent heterocyclic group containing a nitrogen atom in the ring. 2. The fluorenone derivative according to claim 1, wherein the fluorenone derivative is at least one group selected from the group consisting of: 3. K ¹ and / or K ² in the general formula (I)
Is at least one group selected from the groups represented by the general formula (II). 4. K ¹ and / or K ² in the general formula (I)
Is at least one group selected from the groups represented by formulas (III) and (IV). 5. K ¹ and / or K ² in the general formula (I)
Are represented by the general formulas (Va), (Vb), (VI-a), (VI
The fluorenone derivative according to claim 2, wherein the fluorenone derivative is at least one group selected from the groups represented by -b). 6. An electrophotographic photoreceptor comprising a photosensitive layer containing the fluorenone derivative according to claim 1 on a conductive support.