JPH05105652A - Diaminoazulene derivative and electrophotographic sensitizer using the same - Google Patents

Abstract

PURPOSE:To provide the subject novel derivatibe excellent in electric charge transport ability and light stability, capable of giving highly sensitive, and highly durable electrophotographic sensitizers. CONSTITUTION:A compound of formula I[R<1> and R<2> are each H, (substituted) alkyl or (substituted)alkoxy], e.g. N,N,N',N'-tetra(3-methylphenyl)-1,3- diaminoazulene. This compound can be obtained by acetylating 1, 2- diaminoazulene of formula II (pref. its amino groups) with an acetylating agent followed by reaction with a compound of formula III (X is halogen) in the presence of a copper catalyst and basic substance to form a compound of formula IV, which is, in turn, reacted with a compound of formula V in the presence of a copper catalyst and basic substance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaminoazulene derivative suitable as a charge transporting material in an electrophotographic photoreceptor used in an electrostatic copying machine, a laser beam printer or the like, and an electrophotographic photoreceptor using the same. It is about.

[0002]

2. Description of the Related Art In recent years, organic photoconductors are widely used as photoconductors in image forming apparatuses such as copying machines because they are excellent in processability and economy and have a high degree of freedom in functional design. The Carlson process is widely used to form a copied image using a photoconductor. The Carlson process consists of a charging process that uniformly charges the photoconductor by corona discharge, an exposure process that exposes the document image on the charged photoconductor to form an electrostatic latent image corresponding to the document image, and an electrostatic latent image. After development with a developer containing toner, a developing step of forming a toner image, a transfer step of transferring the toner image to paper, a fixing step of fixing the transferred toner image, and a transfer step,
And a cleaning step for removing the toner remaining on the photoconductor. In order to form a high-quality image in the Carlson process, the photoconductor is required to have excellent charging properties and photosensitivity, and to have a low residual potential after exposure.

Conventionally, inorganic photoconductors such as selenium and cadmium sulfide have been known as photosensitive materials, but they have the drawbacks of toxicity and high production cost. Therefore, so-called organic photoconductors using various organic substances in place of these inorganic substances have been proposed. Such an organophotoreceptor has a photosensitive layer composed of a charge generating material that generates a charge upon exposure and a charge transporting material that has a function of transporting the generated charge.

In order to satisfy various conditions desired for such an organic photoreceptor, it is necessary to appropriately select these charge generating material and charge transporting material. Various organic compounds such as carbazole compounds, oxadiazole compounds, pyrazoline compounds, hydrazone compounds, stilbene compounds, and phenylenediamine compounds have been proposed as charge transport materials.

[0005]

However, the above-mentioned conventional charge transport materials have insufficient charge transport ability,
There is a problem that the light stability is inferior. Therefore, the photoconductor using this charge transport material has a drawback that the sensitivity and durability are not sufficient. The purpose of the present invention is to
It is an object of the present invention to provide a compound having excellent charge transporting ability and light stability, which is suitable as a charge transporting material, and an electrophotographic photoreceptor using the compound, which has high sensitivity and excellent durability.

[0006]

Means and Actions for Solving the Problems To solve the above problems, the diaminoazulene derivative of the present invention has the general formula (I):

[0007]

[Chemical 2]

[In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom, or an alkyl group or an alkoxy group which may have a substituent. ] Is represented. Further, the electrophotographic photoreceptor of the present invention for achieving the above object is characterized in that a photosensitive layer containing a diaminoazulene derivative represented by the general formula (I) is provided on a conductive substrate. ..

The diaminoazulene derivative represented by the above general formula (I) has a structure in which azulene, which is known as a quencher, is introduced into the molecule, so that it exhibits a high charge transporting ability and is excellent in light stability. There is. Therefore, the photosensitive layer containing the above diaminoazulene derivative as a charge transport material has high sensitivity and excellent durability.

As described above, the reason why the diaminoazulene derivative represented by the general formula (I) has high sensitivity and photostability is, for example, a conventionally known phenylene in which the azulene moiety is substituted with a benzene ring. Compared to the diamine-based compound, by introducing the azulene moiety, the π-electron conjugated system formed in the molecule has a larger spread, so that the planarization of the molecular structure of the compound is further promoted, and the molecule It is presumed that this is because the intermolecular interaction due to the overlap between the molecules strengthens.

Examples of the alkyl group include lower alkyl groups having 1 to 6 carbon atoms such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group and hexyl group. Be done. Examples of the alkoxy group include lower alkoxy groups having 1 to 6 carbon atoms such as methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, t-butoxy group, pentyloxy group and hexyloxy group. Be done.

Examples of the substituent for substituting the alkyl group and the like include a halogen atom, an amino group, a hydroxyl group, an optionally esterified carboxyl group, a cyano group,
Examples thereof include an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkenyl group having 2 to 6 carbon atoms which may have an aryl group. Specific examples of the diaminoazulene derivative represented by the general formula (I) include the compounds shown below.

[0013]

[Chemical 3]

[0014]

[Chemical 4]

[0015]

[Chemical 5]

The diaminoazulene derivative of the present invention can be synthesized by various methods. For example, it can be synthesized by the method shown in the following reaction formula.

[0017]

[Chemical 6]

(In the formula, R ¹ and R ² are the same as above, and X is a halogen atom.) That is, as shown in the reaction formula,
The azulene derivative represented by the formula (a) is reacted with the compound represented by the formula (b) in the presence of a copper catalyst and a basic substance to give a 1,3-diaminoazulene represented by the formula (c). Obtain the compound. Then, the compound (c) is reacted with the compound represented by the formula (d) in the presence of a copper catalyst and a basic substance to obtain the compound of the present invention represented by the formula (I). In order to obtain the mono-substituted product represented by the formula (c),
The amino group of the azulene derivative represented by the formula (a) is preferably acetylated with an acetylating agent in advance.

All of the above reactions are carried out without solvent or in a solvent. The compound represented by the formula (b) is used in an amount of 2 to 20 times, preferably 3 to 10 times the molar amount of the azulene derivative represented by the formula (a). Further, the compound represented by the formula (d) is 2 to 2 with respect to the compound represented by the formula (c).
It is suitable to use a 0-fold molar amount, preferably a 3- to 10-fold molar amount. The reaction is usually performed at a temperature of 150 to 250 ° C, preferably 170 to 230 ° C.

The copper catalyst to be used includes, for example, copper powder, copper oxide, copper halides and other copper or copper compounds,
The amount thereof is 0.01 to 0.01 with respect to the azulene derivative represented by the formula (a) or the compound represented by the formula (c).
Suitably 1.0 equivalent, preferably 0.1 to 0.5 equivalent. Examples of the basic substance include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and the like, and the amount thereof used is the azulene derivative represented by the formula (a) or the compound represented by the formula (c). On the other hand, it is suitable that the amount is 0.5 to 10 times mol, preferably 1 to 3 times mol.

As the organic solvent, nitrobenzene, dichlorobenzene, quinoline, N, N-methylpyrrolidone,
N-methylpyrrolidone, 1,3-dimethyl-2-imidazoline and the like can be used, but when an excess amount of the compound represented by the formula (b) or the compound represented by the formula (d) is used, it is not necessary. The reaction can be carried out with a solvent. The above acetylation can be performed according to a conventional method. Examples of the acetylating agent include anhydrous acetic acid and chloride.

When R ¹ = R ² in the general formula (I), the compound represented by the formula (b) or the formula (d) can be obtained by a one-step reaction without performing the acetylation. You may make it react. The photoreceptor of the present invention comprises a photosensitive layer containing one or more diaminoazulene derivatives represented by the general formula (I) as a charge transport material.

The photosensitive layer is classified into a so-called single layer type and a laminated type, and the present invention is applicable to both of them. In order to obtain a single-layer type photoreceptor, a photosensitive layer containing a compound represented by the general formula (I), which is a charge transport material, a charge generating material, a binder resin, etc., is applied by means such as coating. It may be formed on the conductive substrate.

In order to obtain a laminated type photoreceptor, a charge generating layer containing a charge generating material is formed on a conductive substrate by means such as vapor deposition or coating, and on this charge generating layer,
A charge transport layer containing the compound represented by the general formula (I) and a binder resin may be formed. Also, contrary to the above,
The charge transport layer may be formed on the conductive substrate, and then the charge generation layer may be formed. Further, in the above-mentioned laminated type photosensitive layer, the charge generating layer may also contain a charge transport material.

As the charge generating material, selenium, selenium-tellurium, selenium-arsenic, amorphous silicon, pyrylium salt, azo compounds, disazo compounds, phthalocyanine compounds, anthanthrone compounds and perylene compounds which have been conventionally used. Examples thereof include compounds, indigo compounds, triphenylmethane compounds, slene compounds, toluidine compounds, pyrazoline compounds, perylene compounds, quinacridone compounds, and pyrrolopyrrole compounds. These charge generation materials can be used alone or in combination of two or more so that they have an absorption wavelength region in a desired region.

The diaminoazulene derivative represented by the general formula (I), which is a charge transporting material, can be used alone or in combination with other conventionally known charge transporting materials. As the conventionally known charge transport material, various electron-withdrawing compounds and electron-donating compounds can be used. Examples of the electron-withdrawing compound include diphenoquinone derivatives such as 2,6-dimethyl-2 ', 6'-ditert-dibutyldiphenoquinone, malononitrile, thiopyran compounds, tetracyanoethylene, 2,4,8-triene. Examples include nitrothioxanthone, 3,4,5,7-tetranitro-9-fluorenone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, and dibromomaleic anhydride.

The electron donating compound is 2,5
-Oxadiazole compounds such as di (4-methylaminophenyl) and 1,3,4-oxadiazole, 9- (4
-Styryl compounds such as diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, triphenylamine compounds, indole compounds Examples thereof include nitrogen-containing cyclic compounds such as compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, and triazole compounds, and condensed polycyclic compounds.

These charge transport materials may be used alone or in combination of two or more. When a charge transporting material having film-forming property such as polyvinylcarbazole is used,
The binder resin is not always necessary. As a binder resin,
Various resins can be used. For example, styrene-based polymer, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene, ethylene-vinyl acetate copolymer , Chlorinated polyethylene, polyvinyl chloride, polypropylene,
Thermoplastic resin such as vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, or silicone resin, Examples thereof include epoxy resins, phenol resins, urea resins, melamine resins, other crosslinkable thermosetting resins, and photocurable resins such as epoxy acrylate and urethane-acrylate. These binder resins may be used alone or in combination of two or more.

The single-layer type organic photosensitive layer and the laminated type organic photosensitive layer include
A sensitizer, a fluorene compound, an antioxidant, a deterioration inhibitor such as an ultraviolet absorber, and an additive such as a plasticizer may be contained. Further, in order to improve the sensitivity of the charge generation layer, known sensitizers such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generation material.

In the laminated type photoreceptor, the charge generating material and the binder resin constituting the charge generating layer can be used in various ratios, but to 100 parts of binder resin (weight part, the same applies hereinafter). 5 to 500 parts, especially 10 to 10 parts of the charge generating material.
It is preferably used in a ratio of 300 parts. The charge generation layer may have an appropriate film thickness, but 0.01 to 5
It is preferably formed to a thickness of 0.1 μm, particularly 0.1 to 3 μm.

The diaminoazulene derivative (charge-transporting material) represented by the general formula (I) constituting the charge-transporting layer and the binder resin are mixed in various amounts within a range that does not hinder the transport of charges and a range that does not crystallize. It is possible to use the above general formula for 100 parts of the binder resin so that the charge generated in the charge generation layer by light irradiation can be easily transported.
A diaminoazulene derivative represented by (I)
It is preferably used in a ratio of 25 parts to 200 parts, especially 25 to 200 parts.
The thickness of the laminated photosensitive layer is 0.01 for the charge generation layer.
It is preferable that the thickness of the charge transport layer is 2 to 100 μm, particularly 5 to 5 μm, especially 0.1 to 3 μm.
The thickness is preferably about 50 μm.

In the single-layer type photoreceptor, the binder resin 10
The charge generating material is 0.1 to 50 parts relative to 0 parts, and more preferably 0.1.
5 to 30 parts, and the diaminoazulene derivative (charge transport material) represented by the general formula (I) is 40 to 200 parts, and particularly 50
Suitably it is up to 100 parts. The thickness of the single-layer type photosensitive layer is preferably 5 to 100 μm, particularly preferably 10 to 50 μm.

In the case of a single-layer type electrophotographic photosensitive member, between the conductive substrate and the photosensitive layer, in the case of the laminated type photosensitive member, between the conductive substrate and the charge generating layer, Between the conductive substrate and the charge transport layer, or between the charge generation layer and the charge transport layer, a barrier layer may be formed to the extent that the characteristics of the photoreceptor are not impaired, and the surface of the photoreceptor is A protective layer may be formed.

As the conductive substrate on which the above layers are formed, various conductive materials can be used.
For example, simple metals such as aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass, plastic materials in which the above metals are vapor-deposited or laminated, and iodide Examples thereof include glass coated with aluminum, tin oxide, indium oxide, or the like.

The conductive substrate may be in the form of a sheet, a drum, or the like, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. Further, the conductive substrate is preferably one having sufficient mechanical strength when used. When each of the above layers is formed by a coating method, the charge generation material, charge transport material, and
A binder resin and the like are mixed with a suitable solvent by a known method, for example, a roll mill, a ball mill, an attritor, a paint shaker or an ultrasonic disperser to prepare a coating solution, which is prepared by a known means. It may be applied and dried.

As the solvent for forming the coating solution, 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, aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride and chlorobenzene, dimethyl ether, diethyl ether, tetrahydrofuran, Examples thereof include ethers such as ethylene glycol dimethyl ether and diethylene glycol dimethyl ether, ketones such as acetone, methyl ethyl ketone and cyclohexanone, esters such as ethyl acetate and methyl acetate, dimethylformaldehyde, dimethylformamide and dimethyl sulfoxide. These solvents may be used alone or in combination of two or more.

Further, a surfactant, a leveling agent or the like may be used in order to improve the dispersibility of the charge transporting material or the charge generating material and the dyeing property. As described above, the charge generation layer may be formed by depositing the charge generation material.

[0038]

The present invention will be described in detail below with reference to examples and comparative examples. Example 1 <Synthesis of diaminoazulene derivative represented by the above formula (1)> (i) 79 g of 1,3-diaminoazulene and acetic acid 16
0 g was charged into the reaction vessel, heated to 50 to 70 ° C., and 110 g acetic anhydride was gradually added dropwise. Then, after stirring at 70 ° C. for about 1 hour, the reaction product was poured into water and stirred for 30 minutes. The precipitated crystals were collected by filtration and dried to obtain 93.4 g of N, N'-diacetyl-1,3-diaminoazulene (yield 77.8%).

(Ii) N, N'-diacetyl derivative 9 thus obtained
While adding 3.4 g of m-iodotoluene 167.6 g, potassium carbonate 70 g and copper powder 11 g into a reaction vessel and introducing nitrogen gas into the reaction vessel, 180 to
It was heated to 220 ° C. and reacted at this temperature for 24 hours.
Water generated by the reaction was removed from the reaction system by a water separator. After cooling, 230 g of 40% potassium hydroxide aqueous solution was added, the temperature was raised to 110 to 120 ° C., and the reaction was performed for 14 hours.
Hydrolysis was performed. After filtering the reaction solution to remove the catalyst,
m-iodotoluene was distilled off and recovered. The residue was poured into n-hexane for crystallization to obtain 101.1 g of N, N'-di (3-methylphenyl) -1,3-diaminoazulene (yield 76.9%).

(Iii) 101.1 g of the obtained N, N'-di (3-methylphenyl) -1,3-diaminoazulene
130 g of m-iodotoluene, 55 g of potassium carbonate
And, together with 7.5 g of copper powder, the mixture was charged into a reaction vessel, heated to 180 to 220 ° C. while introducing nitrogen gas into the reaction vessel, and reacted at this temperature for 48 hours. Water generated by the reaction was removed from the reaction system by a water separator. After cooling, 300 g of toluene was added to the reaction product to dissolve it, the insoluble matter was filtered off, and then toluene and m-iodotoluene were distilled off and recovered. The residue was recrystallized from ethyl acetate to give N, N, N ', N'-tetra (3-methylphenyl) -1,3-diaminoazulene of the formula (1) 120.0
g was obtained (yield 77.5%).

The analysis results of the product are shown below. Elemental analysis results Calculated value (%): C 87.99 H: 6.61 N: 5.40 Actual value (%): C: 87.64 H: 6.82 N: 5.64 Mass spectrometry result C ₃₈ H ₃₄ N ₂ m / e = 518 (calculated value 518.1) Example 2 <Synthesis of diaminoazulene derivative represented by the above formula (2)> m-iodotoluene used in step (iii) of Example 1 Instead of p-iodotoluene in the same amount, the same procedure as in Example 1 was repeated except that N represented by the above formula (2),
N'-di (3-methylphenyl) -N, N'-di (4-
Methylphenyl) -1,3-diaminoazulene 121.
6 g was obtained (yield 78.5%).

The analysis results of the product are shown below. Elemental analysis result Calculated value (%): C: 87.99 H: 6.61 N: 5.40 Actual value (%): C: 88.78 H: 6.44 N: 5.63 Mass spectrometry result C ₃₈ As H ₃₄ N ₂ , m / e = 518 (calculated value 518.1) Example 3 <Synthesis of diaminoazulene derivative represented by the above formula (3)> In steps (ii) and (iii) of Example 1, respectively. In place of the used m-iodotoluene, p-iodotoluene was used in the same amount as in Example 1 in step (ii), and 130 g of p-iodotoluene was used in step (iii). Similarly, N, N, and
N ', N'-tetra (4-methylphenyl) -1,3-
125.1 g of diaminoazulene was obtained (yield 78.3).
%).

The product of step (ii), N, N '
The yield of -di (4-methylphenyl) -1,3-diaminoazulene was 104.3 g (yield 79.3%).
The analysis results of the product are shown below. Elemental analysis result Calculated value (%): C: 87.99 H: 6.61 N: 5.40 Actual value (%): C: 88.24 H: 6.47 N: 5.55 Mass spectrometry result C ₃₈ As H ₃₄ N ₂ , m / e = 518 (calculated value 518.1) Example 4 <Synthesis of diaminoazulene derivative represented by the above formula (4)> m-iodo used in step (iii) of Example 1 N, N′-di (3-methylphenyl) -N, represented by the above formula (4), was used in the same manner as in Example 1 except that 144.7 g of p-iodoanisole was used instead of toluene. 134.0 g of N'-di (4-methoxyphenyl) -1,3-diaminoazulene was obtained (yield 78.8%).

The product of step (ii), N, N '
The yield of -di (3-methylphenyl) -1,3-diaminoazulene was 104.5 g (yield 79.5%).
The analysis results of the product are shown below. Elemental analysis results Calculated value (%): C: 82.88 H: 6.22 N: 5.09 Actual value (%): C: 82.99 H: 6.37 N: 5.32 Mass spectrometry result C ₃₈ M / e = 550 (calculated value 550.7) as H ₃₄ N ₂ O ₂ Example 5 <Synthesis of diaminoazulene derivative represented by the above formula (5)> p used in step (iii) of Example 3 In the same manner as in Example 3 except that 141.8 g of p-iodoanisole was used in place of iodotoluene, N, N′-di (4-methylphenyl) -represented by the above formula (5) was used. 130.2 g of N, N'-di (4-methoxyphenyl) -1,3-diaminoazulene was obtained (yield 78.1%).

In this case, the yield of the product in the step (ii) was 102.4 g (yield 77.9%). The analysis results of the product are shown below. Elemental analysis results Calculated value (%): C: 82.88 H: 6.22 N: 5.09 Actual value (%): C: 82.62 H: 6.25 N: 5.32 Mass spectrometry result C ₃₈ M / e = 550 as H ₃₄ N ₂ O ₂ (calculated value 550.7) Example 6 <Synthesis of diaminoazulene derivative represented by the above formula (6)> Steps (ii) and (iii) of Example 1 In place of the m-iodotoluene used in each step, p-iodoanisole was used in all cases (182.1 g in step (ii) and step (i)).
ii) 142.7 g was used) except that N, N, N ', N' represented by the above formula (6) was used in the same manner as in Example 1.
135.8 g of -tetra (4-methoxyphenyl) -1,3-diaminoazulene was obtained (yield 76.5%).

The product of step (ii), N, N '
The yield of -di (4-methoxyphenyl) -1,3-diaminoazulene was 112.8 g (yield 78.4%). The analysis results of the product are shown below. Elemental analysis result Calculated value (%): C: 78.33 H: 5.88 N: 4.81 Measured value (%): C: 78.54 H: 6.01 N: 4.66 Mass spectrometry result C ₃₈ M / e = 582 as H ₃₄ N ₂ O ₄ (calculated value 582.7) Example 7 <Synthesis of diaminoazulene derivative represented by the above formula (7)> Steps (ii) and (iii) of Example 1 Example 1 was repeated except that 158.7 g of iodobenzene was used in the step (ii) and 138.9 g of p-iodoanisole was used in the step (iii) in place of the m-iodotoluene used in each.
In the same manner as described above, N, N'-diphenyl-N, N'-di (4-methoxyphenyl) -1,3 represented by the above formula (7).
116.2 g of -diaminoazulene was obtained (yield 75.0
%).

The product of step (ii), N, N '
The yield of diphenyl-1,3-diaminoazulene is 12
It was 2.3 g (yield 76.3%). The analysis results of the product are shown below. Elemental analysis result Calculated value (%): C: 82.73 H: 5.79 N: 5.36 Measured value (%): C: 82.54 H: 5.93 N: 5.21 Mass spectrometry result C ₃₆ M / e = 522 (calculated value 522.7) as H ₃₀ N ₂ O ₂ Examples 8 to 14 and Comparative Examples 1 and 2 (multilayer type photoreceptor) 2 parts of the charge generation material represented by the following formula (A) , 1 part of polyvinyl butyral resin and 120 parts of tetrahydrofuran were dispersed for 2 hours with a paint shaker using glass beads (2 mm diameter). The obtained dispersion was applied on the surface of an aluminum tube by a dipping method and dried at 100 ° C. for 1 hour to form a 0.5 μm charge generation layer.

[0048]

[Chemical 7]

A solution prepared by dissolving 1 part of the charge transport material and 1 part of the polyester resin in 9 parts of toluene was applied on the charge generation layer by a dipping method and dried at 100 ° C. for 1 hour to form a 22 μm charge transport layer. Thus, a negative charging type laminated type photoreceptor was obtained.
As Comparative Example 1, a laminated photoreceptor was prepared in the same manner as in Examples 8 to 14 except that the compound represented by the following formula (B) was used as the charge transport material.

[0050]

[Chemical 8]

Examples 15 to 21 and Comparative Examples 3 and 4 (single
( Layered Photoreceptor) 1 part of the charge generating agent represented by the formula (A) and 60 parts of tetrahydrofuran were dispersed in a paint shaker using glass beads (2 mm diameter) for 2 hours. To the obtained dispersion liquid, tetrahydrofuran solution of polyester resin 50
Parts and 10 parts of charge transport material were added and dispersion was continued for another hour. The obtained dispersion liquid was applied to the surface of an aluminum tube by a dipping method to form a photosensitive layer of 20 μm, and a positive charging type single layer type photoreceptor was obtained.

In Comparative Example 3, the compound represented by the above formula (B) was used as the charge transporting material, and the above Examples 15 to
A single-layer type photoconductor was prepared in the same manner as in No. 21. The following tests were carried out on the electrophotographic photosensitive members of the above Examples and Comparative Examples to evaluate their characteristics. Measurement of Initial Surface Potential Each electrophotographic photosensitive member is loaded in an electrostatic copying tester (Gentec Cynthia 30M, trade name, manufactured by Gentech), and the surface thereof is positively or negatively charged to obtain an initial surface potential Vs. .p. (V) was measured.

Measurement of Half-Exposure Amount and Residual Potential The electrophotographic photosensitive member charged in the above-mentioned measurement of the initial surface potential was measured at an exposure intensity of 10 lux by using a halogen lamp as an exposure light source of an electrostatic copying tester. Exposure under the conditions,
The half-exposure amount E1 / 2 (lux.sec) was calculated by obtaining the time until the surface potential became 1/2.

The surface potential was measured at 0.15 seconds after the start of the exposure, and the residual potential V1r.p. (V) was measured.
And Measurement of Light Stability The electrophotographic photosensitive member was loaded in an electrostatic copying machine (model number DC-111 manufactured by Mita Kogyo Co., Ltd.) to continuously copy 1000 sheets, and then repeatedly exposed in the same manner as above. After that, the residual potential V2r.p. (V) was measured. Then, the residual potential V
The difference ΔVr.p. (V) between 1r.p. and V2r.p. was obtained.

The test results of the laminated type photoreceptors (Examples 19 to 30 and Comparative Examples 1 and 2) are shown in Table 1, and the test results of the single layer type photoreceptors (Examples 31 to 42 and Comparative Examples 3 and 4) are shown. Each is shown in Table 2.

[0056]

[Table 1]

[0057]

[Table 2]

From these test results, there is almost no difference in surface potential VS.P. between the laminated type and the single layer type of the photoconductors of the respective examples, although the surface potential VS.P. ,
It was found that the sensitivity was remarkably improved because the half exposure amount E1 / 2 was small and the residual potential V1r.p. was low. In addition, the photoconductors of the above respective examples have Δ
Since the Vr.p. was small, it was found that each of them had excellent durability.

[0059]

INDUSTRIAL APPLICABILITY As described above, the diaminoazulene derivative of the present invention has a high charge transporting ability and is excellent in photostability. Therefore, by using this diaminoazulene derivative as a charge transporting material, An electrophotographic photoreceptor having high sensitivity and excellent durability can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Yamazato 1-2-2 Tamatsukuri, Chuo-ku, Osaka City, Osaka Prefecture Mita Industry Co., Ltd.

Claims (2)

[Claims] 1. General formula (I): [In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom, or an alkyl group or an alkoxy group which may have a substituent. ] The diamino azulene derivative represented by these. 2. An electrophotographic photoreceptor comprising a conductive layer and a photosensitive layer containing a diaminoazulene derivative represented by the general formula (I).