JPH04240653A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having high sensitivity, superior electrostatic chargeability and repetitive characteristics. CONSTITUTION:A photosensitive layer contg. a compd. represented by formula 1 is formed on an electrically conductive substrate. In formula 1, each of R<1> and R<2> is hydroxyl, nitro, cyano, etc., each of (n) and (m) 2 or 3, R<3> is H, alkyl, aralkyl, etc., each of Ar<1> and Ar<2> is aryl, alkyl, etc., and each of Ar<3> and Ar<4> is H, alkyl, aryl, etc.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is applicable to copying machines, printers,
The present invention relates to an electrophotographic photoreceptor used in an image forming apparatus such as a facsimile machine.

0002

2. Description of the Related Art In recent years, organic photoreceptors have been widely used as electrophotographic photoreceptors in image forming apparatuses such as copying machines, which are excellent in processability and economical efficiency and have a large degree of freedom in functional design.

[0003] Furthermore, when forming a copy image using an electrophotographic photoreceptor, the Carlson process is widely used. The Carlson process consists of a charging process in which a photoreceptor is uniformly charged by corona discharge, an exposure process in which an original image is exposed to the charged photoreceptor to form an electrostatic latent image corresponding to the original image, and an electrostatic latent image is transferred to a toner. A development process in which a toner image is formed by developing with a developer containing , and a cleaning step of removing toner remaining on the photoreceptor. In this Carlson process, in order to form a high quality image, the electrophotographic photoreceptor is required to have excellent charging characteristics and photosensitivity characteristics, and to have a low residual potential after exposure.

Conventionally, inorganic photoconductors such as selenium and cadmium sulfide have been known as materials for electrophotographic photoreceptors.
These have the disadvantage of being toxic and having high production costs. Therefore, so-called organic electrophotographic photoreceptors using various organic substances in place of these inorganic substances have been proposed. Such an organic electrophotographic photoreceptor has a photosensitive layer composed of a charge-generating material that generates charges upon exposure to light, and a charge-transporting material that has a function of transporting the generated charges.

In order to satisfy various conditions desired for such an organic electrophotographic photoreceptor, it is necessary to appropriately select the charge generating material and the charge transporting material. Various organic compounds have been proposed and commercialized as charge transport materials, and for example, hydrazone compounds disclosed in Japanese Patent Laid-Open Nos. 54-59143 and 2-210451 are known.

[0006]

However, conventional charge transport materials have the drawback of insufficient sensitivity and repeatability. An object of the present invention is to solve these technical problems and provide an electrophotographic photoreceptor that is highly sensitive and has excellent repeatability.

[0007]

[Means for Solving the Problems] The electrophotographic photoreceptor of the present invention for achieving the above object is characterized by having a photosensitive layer containing a compound represented by the following general formula on a conductive substrate. An electrophotographic photoreceptor.

[0008]

[Case 2]

(In the formula, R1 and R2 are the same or different and are a hydroxyl group, a nitro group, a cyano group, a halogen atom,
Indicates an alkanoyl group, an alkenyl group, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a fused polycyclic group, or a heterocyclic group;
The fused polycyclic group and the heterocyclic group may each have a substituent; n and m are each an integer of 2 or 3; R3 is a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, a fused polycyclic group represents a formula group or a heterocyclic group, and each of the alkyl group, aralkyl group, aryl group, fused polycyclic group and heterocyclic group may have a substituent; Ar
1 and Ar2 are the same or different aryl groups,
It represents an alkyl group, a fused polycyclic group, or a heterocyclic group, and any group may have a substituent; Ar3 and Ar4 are the same or different and are hydrogen atoms, alkyl groups,
It represents an aryl group, a fused polycyclic group, or a heterocyclic group, and each of the alkyl group, aryl group, fused polycyclic group, and heterocyclic group may have a substituent; however, Ar3
and Ar4 must not both be hydrogen atoms, and Ar1 and Ar2 or Ar3 and Ar4 may be combined to form a ring) Examples of the alkanoyl group include formyl group, acetyl group, propionyl group, Examples include butyryl group, isobutyryl group, pentanoyl group, hexanoyl group, and the like.

Examples of the alkenyl group include vinyl group,
Examples include allyl group, crotyl group, 2-pentenyl group, and 2-hexenyl group. Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, and hexyl group.

Examples of the alkoxy group include methoxy group, ethoxy group, isopropoxy group, butoxy group, t-butoxy group, and hexyloxy group. Examples of the aralkyl group include benzyl group, α-phenethyl group, β-phenethyl group, 3-phenylpropyl group, benzhydryl group, and trityl group.

Examples of halogen atoms include fluorine, chlorine, bromine, and iodine. Examples of the fused polycyclic group include naphthyl group and phenanthryl group. Examples of the heterocyclic group include thienyl group, pyrrolyl group, pyrrolidinyl group, oxazolyl group, isoxazolyl group,
Thiazolyl group, isothiazolyl group, imidazolyl group, 2
H-imidazolyl group, pyrazolyl group, triazolyl group,
Examples include a tetrazolyl group, a pyranyl group, a pyridyl group, a piveridyl group, a piperidino group, a 3-morpholinyl group, a morpholino group, and a thiazolyl group. Further, it may be a heterocyclic group condensed with an aromatic ring.

[0013] The above-mentioned substituents include, for example, a halogen atom, an amino group, a hydroxyl group, a carboxyl group that may be esterified, a cyano group, a C1-C6 alkyl group, a C1-C6 alkoxy group, and an aryl group. Examples include certain C2-C6 alkenyl groups. Also, Ar1 and Ar2 or Ar3 and Ar4
may be combined to form a ring, and examples of such a ring include carbazole.

Specific examples of the hydrazone compound represented by the above general formula include the following.

[0015]

[Chemical formula 3]

[0016]

[C4]

[0017]

[C5]

[0018]

[C6]

[0019]

[Chemical 7]

[0020]

[Chemical formula 8]

[0021]

[Chemical formula 9]

The compound represented by the above general formula can be obtained by reacting a corresponding aldehyde compound and a hydrazine compound in a solvent in the presence or absence of a catalyst. The photosensitive layer in the present invention contains one or more compounds represented by the above general formula.

The photosensitive layer in the present invention includes a single layer type in which a charge generating material, a charge transporting material, which is a compound represented by the above general formula, and a binder resin are mixed together, and a charge generating layer and a charge transporting layer laminated together. Although there is a laminated type, the photosensitive layer of the present invention can be applied to either type. In order to obtain a laminated electrophotographic photoreceptor, a charge generation layer containing a charge generation material is formed on a conductive base material, and a charge transport material represented by the above general formula is placed on the charge generation layer. A charge transport layer containing a compound may be formed. Furthermore, the stacking order may be reversed and the charge generation layer may be provided on the charge transport layer.

As charge generating materials, conventionally used selenium, selenium-tellurium, selenium-arsenic, amorphous silicon, pyrylium salts, azo compounds, disazo compounds, phthalocyanine compounds, anthanthrone compounds, and perylene compounds are used. compounds, indigo-based compounds, triphenylmethane-based compounds, threne-based compounds, toluidine-based compounds, pyrazoline-based compounds, perylene-based compounds, quinacridone-based compounds, pyrrolopyrrole-based compounds, and the like. These charge generating materials can be used alone or in combination of two or more.

[0025] Furthermore, the compound represented by the above general formula, which is a charge transporting material, can be used in combination with other conventionally known charge transporting materials. Conventionally known charge transport materials include, for example, oxadiazole compounds such as 2,5-di(4-methylaminophenyl)-1,3,4-oxadiazole, and 9-(4-diethylaminostyryl).
Styryl compounds such as anthracene, carbazole compounds such as polyvinylcarbazole, 1-phenyl-3-
Pyrazoline compounds such as (p-dimethylaminophenyl) pyrazole, triphenylamine compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazoles Examples include nitrogen-containing cyclic compounds such as system compounds, and fused polycyclic compounds. Note that a binder resin is not necessarily required when a charge transporting material having film-forming properties such as polyvinylcarbazole is used.

Various resins can be used as the binder resin, such as styrene polymers, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, and acrylic copolymers. Union,
Styrene-acrylic acid copolymer, polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate , thermoplastic resins such as polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, silicone resin, epoxy resin, and other crosslinkable thermosetting resins, as well as photosensitive resins such as epoxy acrylate and urethane-acrylate. Examples include curable resins. These binder resins can be used alone or in combination of two or more.

Further, examples of the solvent for dissolving the charge generating material, the charge transporting material and the binder resin to prepare a coating solution include methanol, ethanol, isopropanol,
Alcohols such as 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, and dimethyl ether. , ethers such as diethyl ether, tetrahydrofuran, 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, dimethyl formaldehyde, dimethyl formamide, and dimethyl sulfoxide. These solvents can be used alone or in combination of two or more.

Further, in order to improve the sensitivity of the charge generation layer, a known sensitizer such as terphenyl, halonaphthoquinones, acenaphthylene, etc. may be used together with the charge generation material. Furthermore, a surfactant, a leveling agent, etc. may be used to improve the dispersibility, dyeability, etc. of the charge transport material and charge generation material.

Examples of the conductive substrate include aluminum, copper, tin, platinum, silver, vanadium, molybdenum,
Chromium, cadmium, titanium, nickel, palladium,
Single metals such as indium, stainless steel, and brass, and plastic materials on which the above metals are vapor-deposited or laminated;
Examples include glass coated with aluminum iodide, tin oxide, indium oxide, and the like.

The conductive substrate may be in the form of a sheet or a drum, as long as the substrate itself is conductive or the surface of the substrate is conductive. Also,
The substrate preferably has sufficient mechanical strength during use. In the laminated electrophotographic photoreceptor, the charge generation material and the binder resin constituting the charge generation layer can be used in various ratios, but 100 parts of the binder resin (parts by weight,
It is preferable to use 5 to 500 parts, particularly 10 to 250 parts, of the charge generating material (the same applies hereinafter).

[0031] The charge generation layer may have an appropriate thickness, but it may have a thickness of 0.01 to 5 μm, particularly 0.1 to 3 μm.
It is preferable that the diameter is about m. The compound represented by the above general formula (charge transport material) constituting the charge transport layer and the binder resin can be used in various ratios, but the charge generated in the charge generation layer by light irradiation can be easily In order to facilitate transportation, it is preferable to use the compound represented by the above general formula in a proportion of 10 to 500 parts, particularly 25 to 200 parts, per 100 parts of the binder resin.

The charge transport layer is preferably formed to have a thickness of about 2 to 100 μm, particularly about 5 to 30 μm. In a single-layer type electrophotographic photoreceptor, the amount of the charge generating material is 2 to 20 parts, especially 3 to 15 parts, and the amount of the compound represented by the above general formula (charge transporting material) is 40 to 40 parts per 100 parts of the binder resin. 2
00 parts, especially 50 to 150 parts is suitable. Further, the thickness of the single-layer type photosensitive layer is preferably about 10 to 50 μm, particularly about 15 to 30 μm.

When a photosensitive layer including a charge generation layer and a charge transport layer is formed by a coating method, the charge generation material or the charge transport material and the binder resin are mixed by a conventionally known method such as a roll mill, a ball mill, an attritor, or a binder resin. Prepare the coating solution using a paint shaker, ultrasonic disperser, etc.

[0034]

[Function] According to the structure of the present invention, since the compound represented by the above general formula has excellent charge transport ability, by incorporating this compound into the photosensitive layer as a charge transport material, it has excellent sensitivity and charging ability. , an electrophotographic photoreceptor having high repeatability can be obtained.

[0035]

[Examples] The present invention will be explained in detail below with reference to Examples and Comparative Examples. Examples 1 to 9 and Comparative Examples 1 to 5 (laminated photosensitive layer) 2 parts of charge generating material, 1 part of polyvinyl butyral resin ("S-lecBM-5" manufactured by Sekisui Chemical Co., Ltd.), 120 parts of tetrahydrofuran, zirconia Dispersion was carried out for 2 hours using a paint shaker using beads (2 mm diameter). The resulting dispersion was applied onto an aluminum sheet using a wire bar and dried at 100° C. for 1 hour to obtain a charge generation layer of 0.5 μm. The charge generating materials used are shown in Tables 1 and 2. In these tables, charge generating materials A,
B and C are the following formulas (A), (B) and (C
) means a compound represented by

[0036]

[Chemical formula 10]

[0037] On this charge generation layer, 1 part of a charge transport material, a polycarbonate resin ("Z-300" manufactured by Mitsubishi Gas Chemical Co., Ltd.)
A solution prepared by dissolving 1 part of '') in 9 parts of toluene was applied using a wire bar and dried at 100°C for 1 hour to obtain a charge transport layer of 22 μm. The charge transport materials used in Examples 1 to 9 are shown in Tables 1 and 2 by the compound numbers shown in the specific examples above. Further, charge transport materials I to V used in Comparative Examples 1 to 5 refer to compounds represented by the following formulas (I) to (V), respectively.

[0038]

[Chemical formula 11]

Examples 10 to 14 and Comparative Examples 6 to 10 (
Single layer type photosensitive layer) 1 part of a charge generating agent and 60 parts of tetrahydrofuran were dispersed for 2 hours in a paint shaker using zirconia beads (2 mm diameter). A polycarbonate resin with a solid content of 20% by weight (
50 parts of a tetrahydrofuran solution ("Z-300" manufactured by Mitsubishi Gas Chemical Co., Ltd.) and 10 parts of a charge transport material were added, and dispersion was continued for an additional hour. The resulting dispersion was coated onto an aluminum sheet using a wire bar and heated at 100°C for 1
After drying for a while, a 20 μm photosensitive layer was obtained. The charge generation materials and charge transport materials used are as follows in Tables 1 and 2.
As in the above examples, each chemical structure is represented by a number corresponding to its chemical structure.

(Evaluation Test) The surface potential, half-decreased exposure (E1/2), and residual potential of the photoreceptor obtained in each Example and Comparative Example were measured using an evaluation tester ("EPA8100" manufactured by Kawaguchi Electric Co., Ltd.).
”). The measurement conditions are as follows. Light intensity: 50 lux Exposure intensity: 1/15 seconds Surface potential: The inflow current value was adjusted so as to be around (±)700V.

Light source: Tungsten lamp Static elimination: 200 lux Residual potential measurement: Measurement was started 0.2 seconds after the start of exposure. The test results of Examples 1 to 14 are shown in Table 1, and the test results of Comparative Examples 1 to 10 are shown in Table 2.

[0042]

[Table 1]

[0043]

[Table 2]

From these test results, the photosensitive layers of each example showed almost no difference in surface potential from the conventional photoconductor (comparative example), but were superior in half-life exposure and residual potential, and the sensitivity was significantly lower. You can see that it has been improved.

[0045]

[Effects of the Invention] As described above, according to the electrophotographic photoreceptor of the present invention, since a specific compound with excellent charge transport ability is used as a charge transport material, it has excellent chargeability as well as sensitivity. There is an effect.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor comprising a photosensitive layer containing a compound represented by the following general formula on a conductive substrate. [Formula 1] (wherein R1 and R2 are the same or different and are a hydroxyl group, a nitro group, a cyano group, a halogen atom, an alkanoyl group, an alkenyl group, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a fused polycyclic group) or a heterocyclic group; an alkanoyl group, an alkenyl group, an alkyl group, an alkoxy group, an aryl group, an aralkyl group, a fused polycyclic group, and a heterocyclic group each may have a substituent; n and m is an integer of 2 or 3, respectively; R3 represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, a fused polycyclic group, or a heterocyclic group; and the heterocyclic group may each have a substituent; Ar1 and A
r2 are the same or different and are an aryl group, an alkyl group,
It represents a fused polycyclic group or a heterocyclic group, and any group may have a substituent; Ar3 and Ar4 are the same or different and represent a hydrogen atom, an alkyl group, an aryl group,
Indicates a fused polycyclic group or a heterocyclic group, and each of the alkyl group, aryl group, fused polycyclic group, and heterocyclic group may have a substituent; however, Ar3 and Ar
4 must not both be hydrogen atoms, and Ar1 and Ar2 or Ar3 and Ar4 may come together to form a ring)