JPH10260539A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel useful electrophotographic photoreceptor usable in a positively chargeable system and superior in sensitivity and the like characteristics by incorporating a compound obtained by combining a quinone ring with a phenalene through a double bond in a photosensitive layer. SOLUTION: This electrophotographic photoreceptor is provided on a conductive substrate with a photosensitive layer containing as a charge transfer material the phenalene compound represented by the formula in which each of the 4C atoms of the quinone ring may be, independently, substituted by an alkyl, nitro, or cyano group or a halogen atom, and each of 8C atoms of the phenalene ring may be, independently, be substituted by an alkyl, alkoxy, aryl, or hydroxy group or the like. Since this compound is formed by combining the quinone ring with the phenalene ring through the double bond, the molecule of this compound is itself great and the skeleton of the conjugated structure for giving electron mobility is also great and the distance of the electron transfer is extended, thus permitting the electron transfererability to be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member used for a copying machine, a laser printer, and the like, and more particularly, to an electrophotographic photosensitive member using an organic thin film.

[0002]

2. Description of the Related Art In general, electrophotographic devices such as copiers and laser printers are provided with a photosensitive member having a photosensitive layer. At the beginning of the spread of such electrophotographic devices, the photosensitive layer was made of selenium or selenium. It was composed of materials such as tellurium, selenium-arsenic, and amorphous silicon.

[0003] In recent years, however, there has been a demand for a photoreceptor that is low in cost and less polluting the environment. Therefore, a photoreceptor having an organic photosensitive layer is becoming the mainstream in place of a conventionally used photoreceptor. When such organic photosensitive layers are classified according to their structure, they can be broadly classified into single-layer dispersed type photosensitive layers and function-separated type photosensitive layers.

A single-layer dispersion type photosensitive layer is composed of a single layer film in which a charge generating agent is dispersed in a medium of a charge transfer agent, and one layer of the single layer film has both functions of a charge generation function and a charge transfer function. I have it. On the other hand, the function-separated type photosensitive layer is composed of a multilayer film in which a charge generation layer (CGL) and a charge transfer layer (CTL) are laminated, and the charge generation layer has a function of generating charges, and the charge transfer layer has a function of generating charges. The layer has a function of transferring generated charges.

At present, both types of photosensitive layers have been put to practical use, and development of a charge transport agent having high mobility has been awaited in order to improve the sensitivity of either type.

On the other hand, when the organic photosensitive layers are classified by charge type, they are classified into two types: positively chargeable photosensitive layers and negatively chargeable photosensitive layers. Among the currently known charge transfer agents, those that have high mobility and are compatible with practical use are mostly those with hole mobility, and therefore, commercially available electrophotographic devices include negatively charged type A photoreceptor having a photosensitive layer is used.

However, the corona discharge phenomenon used for negatively charging the photosensitive layer involves various problems such as generation of a large amount of ozone due to the discharge, contamination of the indoor environment, and rapid deterioration of the electrophotographic photosensitive member. The inconvenience has occurred.

[0008] With respect to the inconvenience at the time of negative charging, countermeasures have been attempted for electrophotographic equipment of the prior art, and the addition of an ozone trapping filter and the adoption of a special charging method that does not generate ozone are being studied. However, new problems have arisen such as an increase in the size of the apparatus and the complexity of the electrophotographic process, and no solution has been reached.

In order to overcome this situation, recently market demands for a positively charged photoreceptor which generates less ozone, and for that purpose, high mobility electron transfer which can be used for a positively charged photosensitive layer. The development of agents is needed.

Therefore, intensive studies have been made so far, and at present, trinitrofluorenone (T) is used as an electron transfer agent that can be used for such a positively charged photoreceptor.
NF), tetracyanoethylene, tetracyanoquinodimethane (TCNQ), quinone, diphenoquinone, naphthoquinone, anthraquinone, derivatives thereof and the like. However, it has been pointed out that the above-mentioned electron transfer agent has insufficient properties and has the following disadvantages.

Most of these electron transfer agents have poor compatibility with the binder resin and cannot be uniformly dispersed at a high concentration in the photosensitive layer. Therefore, the content is insufficient, and the electrical characteristics cannot be satisfied. TNF has a high electron-accepting property and therefore a high mobility, but is not suitable for practical use because of its high toxicity. Although TCNQ has an extremely high electron accepting property, it has poor compatibility with resins and is strongly colored.
When a photosensitive layer is formed using Q, light that should originally reach the charge generating agent is absorbed and sensitivity is reduced.

As described above, at present, no practical electron transfer agent for realizing a positively charged electrophotographic photosensitive member has been obtained, and further research has been desired.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art, and is a new and useful electronic device which can be used in a positive charging system and has excellent characteristics such as sensitivity. It is intended to provide a photographic photoreceptor.

[0014]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that a compound in which a quinone ring and a phenalene ring are linked by a double bond is contained in the photosensitive layer. As a result, it has been found that a new and useful electrophotographic photoreceptor of a positive charging system can be provided, and the present invention has been completed.

The present invention has been made on the basis of such findings. The invention according to claim 1 is a photosensitive composition containing a phenalene compound represented by the general formula (1) as a charge transfer agent on a conductive support. It is characterized in that a layer is formed.

[0016]

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(In the formula, 1 to 4 carbon atoms on the quinone ring may each independently have an alkyl, aryl, nitro, cyano or halogen atom substituent. And 1 to 8 carbon atoms on the phenalene ring may each independently have a substituent of any of an alkyl group, an alkoxy group, an aryl group, a hydroxyl group, a nitro group, a cyano group and a halogen atom. )

Further, as in the second aspect of the present invention, in the first aspect of the present invention, a photosensitive layer containing a phenalene compound represented by the general formula (2) as a charge transfer agent is provided on the conductive support. It is also effective when formed.

[0019]

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(Wherein R ₁ and R ₂ each independently represent a lower alkyl group, an aryl group, a nitro group, a cyano group or a halogen atom, and R ₃ each independently represent an alkyl group, an alkoxy group, an aryl group A hydroxyl group, a nitro group, a cyano group or a halogen atom.)

Further, as in the invention of claim 3, in the invention of claim 2, it is also preferable that R ₁ and R ₂ are t-butyl groups and R ₃ is an ethoxy group.

In the first to third aspects of the present invention, the photosensitive layer contains a phenalene compound having a skeleton represented by the general formula (1), and such a compound is formed by connecting a quinone ring and a phenalene ring by a double bond. Therefore, the following features are exhibited by this structure.

First, since the molecule of the compound itself is large and the skeleton of the conjugate structure that imparts electron mobility is large, the electron transfer distance in the molecule is long and the electron mobility is high.

When there is no substituent, the molecule has a planar structure, but the molecular structure is distorted by increasing the number of substituents or introducing a bulky substituent, and the molecule is deformed when electrons are transferred. Since the molecular vibration is increased, the electron mobility is high and the sensitivity is improved. In addition, since the molecular structure is asymmetric, resin compatibility is improved, and the electron transfer agent can be uniformly dispersed at a high concentration in the photosensitive layer, so that desired electric characteristics can be satisfied.

Moreover, it is easy to arbitrarily change these functions depending on the combination of the substituents, thereby making it possible to improve the characteristics of the electrophotographic photosensitive member.

On the other hand, the photosensitive layer in the electrophotographic photosensitive member is
Since it is common to include a charge generating agent and a charge transfer agent together with the binder resin, it is necessary that the compatibility between the binder resin and each of the materials is good. The compatibility can be improved by introducing a substituent.

As described above, the phenalene compound used in the present invention not only exhibits a high electron mobility, but also can be designed for a molecule according to a function required as a material used for an electrophotographic photosensitive member. An electron transfer agent based on such an idea has been hitherto unknown.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the electrophotographic photosensitive member according to the present invention will be described in detail.

FIGS. 1 and 2 are cross-sectional views showing the structure of a preferred embodiment of the electrophotographic photosensitive member according to the present invention.

FIG. 1 shows an example of the structure of a function-separated type electrophotographic photosensitive member applicable to the present invention. A charge generation layer 2 and a charge transfer layer are formed on a cylindrical conductive support 1. Layer 3
Are formed in this order, and the charge generation layer 2 and the charge transfer layer 3 constitute a photosensitive layer 4.

FIG. 2 shows an example of the structure of a single-layer type electrophotographic photosensitive member applicable to the present invention. A charge generating agent and a charge transfer agent are provided on a conductive support 1. The photosensitive layer 4 is formed.

The conductive support 1 which can be used in the present invention includes a single metal such as aluminum, brass, stainless steel, nickel, chromium, titanium, gold, silver, copper, tin, platinum, molybdenum, indium, and the like. Workpieces of alloys, conductive materials such as the above metals and carbon were treated by vapor deposition, plating, and other methods, and plastic plates and films having conductivity were further coated with tin oxide, indium oxide, and aluminum iodide. The conductive support 1 can be formed by using various conductive materials, such as conductive glass, without being limited by the type or shape. In general, a cylindrical aluminum tube itself or a tube whose surface is anodized or coated with a conductive resin is often used.

The charge generating layer 2 in the electrophotographic photosensitive member shown in FIG. 1 has at least a charge generating agent,
The charge generation layer 2 can be formed by binding a charge generation agent on a conductive support 1 serving as a base using a binder resin.

As a method for forming the charge generation layer 2, various methods such as a known method can be used. A coating solution in which a charge generation agent is dispersed or dissolved in a suitable solvent together with a binder resin is prepared by a predetermined method. A method of applying the composition on the conductive support 1 serving as a base and drying the composition can be used.

The charge generating layer 2 can be formed by vacuum-depositing a charge generating agent.

The charge transfer layer 3 has at least a charge transfer agent to be described later. The charge transfer layer 3 is formed, for example, by bonding the charge transfer agent on the charge generation layer 2 as a base thereof using a binder resin. It can be formed by attaching.

As a method for forming the charge transfer layer 3, various methods such as a known method can be used. In a usual case, a coating solution in which a charge transfer agent is dispersed or dissolved in a suitable solvent together with a binder resin. Can be applied on the charge generating layer 2 serving as a predetermined base and then dried.

On the other hand, the electrophotographic photosensitive member shown in FIG. 2 has a photosensitive layer 4 in which a charge generating agent and a charge transfer agent are dispersed on a conductive support 1.

Here, as a method for forming the photosensitive layer 4, various methods such as a known method can be used. However, the above-described charge generating agent is dispersed or dissolved in a suitable solvent together with a binder resin, and further described below. A method in which a coating solution in which the charge transfer agent is dissolved is applied onto the conductive support 1 serving as a predetermined base and dried.

As the charge generating agent that can be used in the electrophotographic photoreceptor of the present invention, disazo pigments and oxytitanium phthalocyanine are preferable in terms of good sensitivity compatibility, but are not limited thereto. In addition, for example, selenium, selenium-tellurium, selenium-arsenic, amorphous silicon,
Other phthalocyanine pigments, monoazo pigments, trisazo pigments, polyazo pigments, indigo pigments, sulene pigments, toluidine pigments, pyrazoline pigments, perylene pigments, quinacridone pigments, pyrylium salts and the like can be used. These charge generating agents may be used alone or in combination of two or more in order to obtain an appropriate photosensitivity wavelength and sensitizing effect.

The binder resin that can be used to form the photosensitive layer 4 includes polycarbonate resin, styrene resin, acrylic resin, styrene-acryl resin, ethylene-vinyl acetate resin, polypropylene resin, vinyl chloride resin, and chlorinated polystyrene. Ether, vinyl chloride-vinyl acetate resin, polyester resin, furan resin, nitrile resin, alkyd resin, polyacetal resin, polymethylpentene resin, polyamide resin, polyurethane resin, epoxy resin, polyarylate resin, diallylate resin,
Polysulfone resin, polyether sulfone resin, polyallyl sulfone resin, silicone resin, ketone resin, polyvinyl butyral resin, polyether resin, phenol resin, EVA (ethylene / vinyl acetate / copolymer) resin, ACS (acrylonitrile / chlorinated polyethylene)・
(Styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, and photo-curable resin such as epoxy arylate. These may be used alone or a copolymer may be used, or two or more of them may be used in combination. In addition, it is preferable to use a mixture of resins having different molecular weights because hardness and abrasion resistance can be improved.

The solvent used for the coating solution is methanol,
Ethanol, n-propanol, i-propanol, alcohols such as butanol, pentane, hexane, heptane, octane, cyclohexane, saturated aliphatic hydrocarbons such as cycloheptane, aromatic hydrocarbons such as toluene and xylene, dichloromethane, dichloroethane, Chlorine hydrocarbons such as chloroform and chlorobenzene, dimethyl ether, diethyl ether, tetrahydrofuran (TH
F), ethers such as methoxyethanol, acetone,
Ketones such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl formate, propyl formate,
Methyl acetate, ethyl acetate, propyl acetate, butyl acetate,
Esters such as methyl propionate, N, N-dimethylformamide, dimethyl sulfoxide and the like. These may be used alone or as a mixture of two or more solvents.

The electrophotographic photosensitive member of the present invention has a photosensitive layer 4
It contains a phenalene compound represented by the general formula (1) as a charge transfer agent.

[0044]

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(In the formula, 1 to 4 carbon atoms on the quinone ring may each independently have an alkyl, aryl, nitro, cyano, or halogen atom substituent. , 1 to 8 carbon atoms on the phenalene ring may each independently have an alkyl, alkoxy, aryl, hydroxyl, nitro, cyano, or halogen atom substituent.)

In this case, the photosensitive layer 4 may contain a phenalene compound represented by the general formula (2) as a charge transfer agent.

[0047]

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(Wherein, R ₁ and R ₂ each independently represent a lower alkyl group, an aryl group, a nitro group, a cyano group or a halogen atom, and R ₃ each independently represent an alkyl group, an alkoxy group or an aryl group. Group, a hydroxyl group, a nitro group, a cyano group, or a halogen atom.) Examples of such a compound include those represented by the formula (3).

[0049]

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In the formula (3), t-Bu represents a t-butyl group, and OEt represents an ethoxy group.

Further, other charge transfer agents can be added to these charge transfer agents. In that case, the sensitivity can be increased or the residual potential can be reduced.
The characteristics of the electrophotographic photoreceptor of the present invention can be improved.

Examples of charge transfer agents that can be added to improve such properties include polyvinyl carbazole, halogenated polyvinyl carbazole, polyvinyl pyrene, polyvinyl indoloquinoxaline, polyvinyl benzothiophene, polyvinyl anthracene, polyvinyl acridine,
Polyvinyl pyrazoline, polyacetylene, polythiophene, polypyrrole, polyphenylene, polyphenylene vinylene, polyisothianaphthene, polyaniline, polydiacetylene, polyheptadiene, polypyridinediyl, polyquinoline, polyphenylene sulfide, polyferrosenylene, polyperinaphthylene, polyphthalocyanine And other conductive high molecular compounds can be used. or,
As low molecular compounds, trinitrofluorenone, tetracyanoethylene, tetracyanoquinodimethane, quinone,
Diphenoquinone, naphthoquinone, anthraquinone and derivatives thereof, anthracene, pyrene, polycyclic aromatic compounds such as phenanthrene, indole, carbazole,
Nitrogen-containing heterocyclic compounds such as imidazole, fluorenone, fluorene, oxadiazole, oxazole, pyrazoline, hydrazone, triphenylmethane, triphenylamine, enamine, stilbene, butadiene compounds and the like can be used.

A polymer solid electrolyte in which a polymer compound such as polyethylene oxide, polypropylene oxide, polyacrylonitrile, and polymethacrylic acid is doped with a metal ion such as Li ion can also be used.

Further, an organic charge transfer complex formed of an electron-donating compound represented by tetrathiafulvalene-tetracyanoquinodimethane and an electron-accepting compound can also be used. However, desired photoconductor characteristics can be obtained even when two or more compounds are mixed and added.

The coating solution for producing the photoreceptor of the present invention contains a coating solution which does not impair the characteristics of the electrophotographic photoreceptor.
Antioxidants, ultraviolet absorbers, radical scavengers, softeners,
By adding a curing agent, a crosslinking agent, etc., the characteristics, durability,
The mechanical properties can be improved.

Further, if a dispersion stabilizer, an antisettling agent, an anti-segregation agent, a leveling agent, an antifoaming agent, a thickening agent, a matting agent, etc. are added, the finished appearance of the photoreceptor and the service life of the coating solution are obtained. Can be improved.

Further, in the electrophotographic photoreceptor of the present invention, an undercoat layer having an adhesive function, a barrier function, a function of covering defects on the surface of the substrate, etc. is provided between the conductive support 1 and the photosensitive layer 4. Is also good. As the undercoat layer, aluminum oxide, polyethylene resin, acrylic resin, epoxy resin, polycarbonate resin, polyurethane resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, polyamide resin, nylon resin and the like can be used. These undercoat layers may be composed of a single resin, or may be composed of a mixture of two or more resins. Further, an undercoat layer in which a metal oxide or carbon is dispersed in a resin can be used.

In addition, an organic thin film such as a polyvinyl formal resin, a polycarbonate resin, a fluorine resin, a polyurethane resin, or a silicon resin, or a siloxane structure formed of a hydrolyzate of a silane coupling agent is formed on the photosensitive layer 4. A surface protective layer may be provided by forming a thin film comprising
In that case, the durability of the photoconductor is improved, which is preferable. This surface protective layer may be provided to improve functions other than the enhancement of durability.

[0059]

EXAMPLES Examples of the electrophotographic photosensitive member according to the present invention will be described in detail below. First, an example of a method for producing the compound represented by the general formula (1) will be described.

<Preparation Example> Under a nitrogen atmosphere, 27.7 ml of a dichloromethane (1 mol / l) solution of triethyloxonium tetrafluoroborate was added to 100 ml of an anhydrous dichloromethane solution of 5.0 g of perinaphthenone, and the solution was added.
Refluxed at 2.5 ° C. for 2.5 hours. The precipitate was filtered, washed with dichloromethane, and dried under reduced pressure to obtain 4.6 g of an orange solid in a yield of 57%. It was confirmed from the following measured values that this substance was 1-ethoxyphenalnium-ion-tetrafluoroborate.

Mp 164-170 ° C. (dec.) (Literature value) mp 170-171 ° C. (dec.) IR (KBr): 775, 830, 1085, 1125, 1240, 1560, 1580, 1620, 1640, 3060 cm ^{. -1 1 H-NMR (CD} 3 NO 2) δ: 1.79 (t, 3H, -CH 3), 5.03 (q, 2H, -O-CH 2 -), 7.90-9.49 (m, 8H, aromatic H ). MS (m / z): 209 (M ⁺ -BF ₄ ). (Molecular weight: 296.07)

Next, under a nitrogen atmosphere, 4.6 g of the above-mentioned 1-ethoxyphenalenium-ion-tetrafluoroborate and 3.2 g of 2,6-di-t-butylphenol were added.
2.0 g of N, N-diisopropylethylamine was added to 100 ml of a solution of the anhydrous acetonitrile. 3 at room temperature
After stirring for a while, the crude crystals obtained by filtration and washing with water were recrystallized from acetonitrile to give dark blue needles (1.7).
g (26% yield).

This substance is represented by the following formula (3):
-Di-t-butyl-4- (3-ethoxyphenalene-1
-Ylidene) -2,5-cyclohexadien-1-one was confirmed from the following measured values.

[0064]

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[0065] mp 188-190 ° C. (literature value) mp 190-192 ℃ IR (KBr) :. 775, 925, 1050, 1240, 1265, 1310, 1355, 1450, 1555, 1580, 2955 cm -1 1 H- NMR (CDCl ₃ ) δ: 1.37 and 1.45 (each s, 18H, tert-Bu), 1.60 (t, 3H, -CH ₃ ), 4.31 (q, 2H, -O-CH _2- ), 6.92-8.15 ( . m, 9H, aromatic H) 13 C-NMR (CDCl 3) δ: 14.57 (-OCH 2 CH 3), 29.78 (-C (C H 3) 3), 35.36 (- C (CH 3) 3), 64.00 (-OCH ₂ CH ₃ ), 104.10, 123.29, 125.99, 126.82, 127.04 (= CH-), 128.53, 128.75, 128.94 (= C <), 130.44, 131.34 (= CH-), 133.04 (= C < ), 133.24, 134.74 (= CH-), 146.23, 147.18, 147.99, 156.34 (= C <), 185.09 (> C = O). MS (m / z): 412 (M ⁺ ). (Molecular weight: 412.57) elemental analysis (C ₂₉ H ₃₂ O ₂₎ calculated C: 84.43, H: 7.82, O:. 7.76 Found C: 84.20, H: 7.60, O: 7.90.

Hereinafter, specific examples of the electrophotographic photosensitive member according to the present invention will be described together with comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

Example 1 After dry-kneading 2 parts by weight of a disazo pigment represented by the formula (4) and 1 part by weight of polyvinyl butyral as a binder resin, 16 parts by weight of 1,4-dioxane and 4 parts by weight of acetone were used in a sand mill. With solvent as 2
After dispersion for an hour, an aluminum drum serving as the conductive support 1 was dip-coated on the dispersion and dried to form a charge generation layer 2 having a thickness of 0.5 μm.

Next, a coating liquid comprising 5 parts by weight of the phenalene compound represented by the formula (3), 10 parts by weight of polycarbonate and 100 parts by weight of tetrahydrofuran (THF) was prepared, and the charge generation layer 2 was formed in this coating liquid. The drum was applied by dip coating and dried at 80 ° C. for 1 hour to form a charge transfer layer 3 having a thickness of 20 μm, thereby producing an electrophotographic photosensitive member.

[0069]

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[0070]

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<Example 2> A pressure of 10 ^-5 torr and a heating temperature of 50 were placed on an aluminum drum as the conductive support 1.
A charge generating layer 2 is formed by depositing high-purity oxytitanyl phthalocyanine so as to have a film thickness of 500 angstroms at 0 ° C., and a charge transfer layer 3 is formed in the same manner as in Example 1 to obtain an electrophotographic photosensitive member. Manufactured.

Example 3 5 g of high-purity oxytitanium phthalocyanine was dry-pulverized together with 50 ml of glass beads by a paint shaker for 100 hours. Next, 50 ml of n-propanol and 5 g of polyvinyl butyral are added, and wet milling is performed for 1 hour. Further, 100 ml of methyl ethyl ketone is added as a solvent and dispersed for 10 hours. The obtained dispersion is applied onto an aluminum drum as a conductive support 1 by dip coating, and dried to form a charge generating layer 2 having a thickness of 0.2 μm. Formed to produce an electrophotographic photoreceptor.

Example 4 1 part by weight of a disazo pigment represented by the formula (4) as a charge generating agent and 10 parts by weight of polycarbonate as a binder resin were kneaded and dispersed in a sand mill for 10 hours using 80 parts by weight of THF as a solvent, and further a charge transfer agent. As a result, 9 parts by weight of the TPD derivative represented by the formula (5) and 2 parts by weight of the phenalene compound represented by the formula (3) were dissolved to prepare a coating liquid. Then, using this coating solution, dip coating is performed on an aluminum drum as the conductive support 1, and dried at 80 ° C. for 1 hour to form a photosensitive layer 4 having both a charge generation and a charge transfer of 20 μm in thickness. Then, an electrophotographic photosensitive member was manufactured.

[0074]

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[0075]

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[0076]

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Example 5 1 part by weight of high-purity oxytitanyl phthalocyanine as a charge generating agent and 10 parts by weight of polycarbonate as a binder resin were kneaded and dispersed in a sand mill for 10 hours using 80 parts by weight of THF as a solvent. A coating liquid was prepared by dissolving 9 parts by weight of the TPD derivative shown in 5) and 2 parts by weight of the phenalene compound shown in formula (3). Then, using this coating solution, dip coating is performed on an aluminum drum as the conductive support 1,
After drying at 1 ° C. for 1 hour, a photosensitive layer 4 having a thickness of 20 μm and having both charge generation and charge transfer was formed, thereby producing an electrophotographic photoreceptor.

[0078]

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[0079]

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Example 6 After dry-kneading 2 parts by weight of a disazo pigment represented by the formula (4) and 1 part by weight of polyvinyl butyral as a binder resin, 16 parts by weight of 1,4-dioxane and 4 parts by weight of acetone were used in a sand mill. With solvent as 2
After dispersion for a time, an aluminum drum as the conductive support 1 was dip-coated on the dispersion and dried to form a charge generation layer 2 having a thickness of 0.5 μm.

Next, 10 parts by weight of the TPD derivative represented by the formula (5) and 1 part by weight of the phenalene compound represented by the formula (3) are used as the charge transfer agent, 10 parts by weight of the polycarbonate is used as the binder resin, and 100 parts by weight of THF is dissolved in the solvent. A coating solution was prepared, and the charge generating layer 2 was added to the coating solution.
The drum on which was formed was dip-coated and dried at 80 ° C. for 1 hour to form a charge transfer layer 3 having a thickness of 20 μm, thereby producing an electrophotographic photoreceptor.

[0082]

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[0083]

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[0084]

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Comparative Example 1 An electrophotographic photoreceptor was manufactured in the same manner as in Example 6, except that the phenalene compound of the formula (3) was not contained.

(Measurement Conditions) A corona discharger was set so that the corona discharge current was 17 μA, and the electrophotographic photosensitive members of Examples 1 to 5 were positively charged by performing corona discharge in a dark place. . Thereafter, exposure was performed with white light, and an exposure amount (half reduction exposure amount: lux × sec) at which the surface potential of each electrophotographic photosensitive member was reduced by half from 700 V to 350 V was measured. The half-exposure amount is a value indicating the sensitivity of the electrophotographic photosensitive member.

In Example 6 and Comparative Example 1, the photoreceptor was negatively charged by corona discharge at a voltage set so that the corona discharge current was 17 μA, and was then exposed to white light to have a surface potential of −700 V. From-to -350 V was determined.

(Measurement Results) The measurement results of Examples 1 to 6 are as shown in Table 1.

[0089]

[Table 1]

In Examples 1 to 3, the charge transfer layer 3 was formed on the charge generation layer 2 containing oxytitanium phthalocyanine or azo pigment as the charge generation agent.
As can be understood from the above, it was confirmed that the half-exposure amount was large, electron transfer occurred, and good photosensitive characteristics were obtained.

In Examples 4 and 5, the photosensitive layer 4 is a single-layer type in which a charge generating agent and a charge transfer agent are contained. Also in this example, good photosensitive characteristics were obtained. It could be confirmed.

Further, in Example 6 and Comparative Example 1, the same type of electrophotographic photoreceptor as in Examples 1 to 3 was negatively charged, but the electrophotographic photosensitive member of Example 6 containing the phenalene compound was negatively charged. In this case, better photosensitive characteristics were obtained as compared with Comparative Example 1 containing no phenalene compound, and the sensitizing effect of the phenalene compound according to the present invention was confirmed.

[0093]

As described above, since the electrophotographic photoreceptor of the present invention contains an electron transfer agent in the photosensitive layer, it can be used particularly in a positive charging system.

Since the electron transfer agent in the photosensitive layer has a large conjugated structure skeleton, the electron has a long moving distance in the molecule, and the molecular vibration is large, so that a photosensitive layer having high electron mobility and high sensitivity can be obtained. be able to.

Further, since the compatibility with the binder resin is good, the electron transfer agent can be dispersed in a large amount and uniformly in the photosensitive layer, and a highly sensitive electrophotographic photosensitive member can be obtained.

Further, in the present invention, sensitivity and compatibility characteristics can be easily improved by changing the substituent of the charge transfer agent to another substituent.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a laminated electrophotographic photosensitive member.

FIG. 2 is a cross-sectional view illustrating an example of a single-layer electrophotographic photosensitive member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conductive support 2 ... Charge generation layer 3 ... Charge transfer layer 4 ... Photosensitive layer

[Procedure amendment]

[Submission date] April 17, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0065

[Correction method] Change

[Correction contents]

Mp 188-190 ° C. (literature value) mp 190-192 ° C. IR (KBr): 775,925,1050,1240,1265,1310,1355,1450,1555,1580,2955 cm ^-1 . ¹ H-NMR (CDCl ₃ ) δ: 1.37 and 1.45 (eachs, 18H, tert-Bu), 1.60 (t, 3H, —CH ₃ ), 4.31 (q, 2H, −0) _{-CH 2 -), 6.92-8.15 (m} , 9H, aromatic H). _{^{13 C-NMR (CDCl 3)}} δ: 14.57 (-0CH 2 C H 3), 29.78 (-C (C H 3) 3), 35.36 (- C (CH 3) 3), 64 _{.00 (-0CH 2 C H 3)} , 104.10,123.29,125.99,126. 82, 127.04 (= CH-), 128.53, 128.75, 128.94 (= C <), 130.44, 131.34 (= CH-), 133.04 (= C <), 133.24, 134.74 (= CH-), 146.23, 147.18, 147.99, 156. 34 (= C <), 185.09 (> C = 0). MS (m / z): 412 (M ^<+> ). (Molecular weight: 412.57) Elementary analysis _{(C 29 H} 32 _O 2) Calculated C: 84.43, H: 7.82,0: 7.76. Obtained value: C: 84.20, H: 7.60, 0: 7.90.

Claims (3)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer containing a phenalene compound represented by the general formula (1) as a charge transfer agent on a conductive support. Embedded image (In the formula, 1 to 4 carbon atoms on the quinone ring may each independently have any substituent of an alkyl group, an aryl group, a nitro group, a cyano group, or a halogen atom. Each of the above 1 to 8 carbon atoms may independently have an alkyl, alkoxy, aryl, hydroxyl, nitro, cyano, or halogen atom substituent.) 2. The electrophotographic photosensitive member according to claim 1, wherein a photosensitive layer containing a phenalene compound represented by the general formula (2) as a charge transfer agent is formed on the conductive support. body. Embedded image (Wherein, R ₁ and R ₂ each independently represent a lower alkyl group, an aryl group, a nitro group, a cyano group or a halogen atom, and R ₃ each independently represent an alkyl group, an alkoxy group, an aryl group, a hydroxyl group. , A nitro group, a cyano group or a halogen atom.) 3. The electrophotographic photoreceptor according to claim 2, wherein R ₁ and R ₂ are t-butyl groups, and R ₃ is an ethoxy group.