JPH04288055A - Hydrazone compound and electrophotographic photoreceptor produced by using the same - Google Patents

Abstract

PURPOSE:To provide a new compound having excellent static chargeability, sensitivity and stability to repeated use, exhibiting high compatibility and flexibility and useful as an electrophotographic photoreceptor. CONSTITUTION:The compound of formula I [R<1> and R<2> are H, alkyl, alkoxy, aryl, halogen, etc.; Ar<1> to Ar<4> are alkyl, aryl, condensed polycyclic group or heterocyclic group; Ar<1> and Ar<2> or Ar<3> and Ar<4> may together form a ring; X is residue to form a condensed ring together with a benzene ring; m and n are 0 or 1). The compound can be produced by reacting an aldehyde compound of formula II with a compound of formula III (R<3> is alkyl) in the presence of a base and reacting the obtained compound of formula IV with a hydrazine compound of formula V under acidic condition (with acetic acid, etc.) in a solvent (e.g. DMF) at a temperature between room temperature and 80 deg.C. An electrophotographic photoreceptor can be produced by applying a photosensitive layer containing the compound of formula I on an electrically conductive substrate.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel hydrazone compound and an electrophotographic photoreceptor using the same.

0002

BACKGROUND OF THE INVENTION In recent years, organic photoreceptors have been widely used as electrophotographic photoreceptors in image forming apparatuses such as copying machines, printers, facsimile machines, etc., as they are excellent in processability and economical efficiency and have a large degree of freedom in functional design. Further, when forming a copy image using an electrophotographic photoreceptor, the Carlson process is widely used. The Carlson process is
A charging process in which the photoconductor is uniformly charged by corona discharge, an exposure process in which the charged photoconductor is exposed to an original image to form an electrostatic latent image corresponding to the original image, and the electrostatic latent image is developed using toner. A developing process in which a toner image is formed by developing with a toner image, a transfer process in which the toner image is transferred to a base material such as paper, a fixing process in which the toner image transferred to the base material is fixed, and after the transfer process, a toner image is formed on the photoreceptor. and a cleaning step to remove residual toner. In this Carlson process,
In order to form high-quality images, an electrophotographic photoreceptor is required to have excellent charging characteristics and photosensitive 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.

[0004] In order to satisfy various conditions desired for such an organic electrophotographic photoreceptor, it is necessary to appropriately select these charge generating materials and charge transporting materials. Various organic compounds have been proposed as charge transport materials.
For example, JP-A No. 2-210453 describes a hydrazone compound represented by the following general formula as a charge transport material in order to provide a photoreceptor with excellent sensitivity, charging ability, and repeatability. ing.

[0005]

[Chemical formula 3]

(In the formula, R1, R2, Ar1, Ar
2, Ar3, Ar4 and Z represent the groups described in the above publication. )

[0007]

[Problems to be Solved by the Invention] However, when the hydrazone compound described in the above-mentioned publication is used, it has low compatibility with the binder resin constituting the photosensitive layer, and the hydrazone compound described in the above publication has low compatibility with the binder resin constituting the photosensitive layer. It has the disadvantage of poor flexibility. If the photoreceptor film has poor flexibility, it is not practical because there is a risk that the photoreceptor may crack or peel off from the conductive substrate when the photoreceptor is used in the form of a small-diameter drum or belt. .

The purpose of the present invention is to solve the above technical problems and to provide a hydrazone compound which has high sensitivity and excellent repeatability, is highly compatible and has excellent flexibility, and an electrophotographic sensitizer using the same. It's about giving your body.

[0009]

[Means and effects for solving the problems] The hydrazone compound of the present invention for achieving the above object has the general formula (1):

0010

[C4]

(In the formula, R1 and R2 are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom, and each of the alkyl group, alkoxy group, and aryl group has a substituent. Ar1, Ar2, Ar3 and Ar4 are the same or different and represent an alkyl group, an aryl group, a fused polycyclic group, or a heterocyclic group, and any of these groups may have a substituent, and Ar1 and Ar2 and Ar
3 and Ar4 may each form a ring;
X represents a residue that forms a condensed ring with the benzene ring, and may have a substituent; m and n are 0, 1 or 2
shows. However, m and n must not be 0 at the same time. ).

The hydrazone compound of the present invention is effective as a charge transport material, particularly a hole transport material, and has higher hole mobility than conventional charge transport materials such as hydrazone compounds. Further, the hydrazone compound of the present invention has excellent compatibility with the binder resin and can form a uniform photosensitive layer, and the resulting photosensitive layer is also highly flexible.

[0013] Therefore, the electrophotographic photoreceptor of the present invention is characterized in that a photosensitive layer containing a hydrazone compound represented by the above general formula (1) is provided on a conductive substrate. The electrophotographic photoreceptor has excellent flexibility, so even when used in the form of a small-diameter photoreceptor drum or belt, it does not cause problems such as cracks in the photoreceptor layer, and has a high sensitivity. It has excellent charging ability and high repeatability.

Examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group,
Examples include isobutyl group, t-butyl group, pentyl group, and hexyl group. Examples of the aryl group include phenyl group, naphthyl group, biphenylyl group, anthryl group, and phenanthryl group.

Examples of the alkoxy group include methoxy group, ethoxy group, isopropoxy group, butoxy group, t-butoxy group, and hexyloxy group. Examples of halogen atoms include chlorine, iodine, bromine, and fluorine. Examples of the fused polycyclic group include residues of various fused polycyclic compounds, such as triphenylene, pyrene, chrysene, naphthacene, picene, perylene, benzo[α]pyrene, rubicene, coronene, obalene, and the like.

Examples of the heterocyclic group include thienyl group,
Pyrrolyl group, pyrrolidinyl group, oxazolyl group, isoxazolyl group, thiazolyl group, isothiazolyl group, imidazolyl group, 2H-imidazolyl group, pyrazolyl group, triazolyl group, tetrazolyl group, pyranyl group, pyridyl group, piveridyl group, piperidino group, 3-morpholinyl group group, morpholino group, thiazolyl group, etc.

Examples of substituents that may be substituted on the above groups include halogen atoms, amino groups that may have substituents such as alkyl, hydroxyl groups, carboxyl groups that may be esterified, cyano groups, Examples thereof include a C1-C6 alkyl group, a C1-C6 alkoxy group, and a C2-C6 alkenyl group that may have an aryl group. There may be two or more substituents, and two substituents may form a ring.

Further, Ar1 and Ar2 and/or Ar3 and Ar4 may be combined to form a ring, and examples of such a ring include carbazole. A group that indicates a residue that forms a condensed ring with a benzene ring and may have a substituent: X is, for example, a group having 2 to 3 carbon atoms that forms a carbazolyl group, indolyl group, quinolyl group, etc. with a benzene ring. Examples include saturated or unsaturated hydrocarbon groups (ethylene group, propylene group, vinyl group, etc.).

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

[0020]

[C5]

[0021]

[C6]

[0022]

[C7]

The compound represented by the general formula (1) is:
For example, it can be produced using the following reaction formula. Reaction formula:

[0024]

[Chemical formula 8]

(In the formula, R1, R2, Ar1, Ar
2, Ar3, Ar4 and X are the same as above, R3
is an alkyl group. ) That is, by reacting an aldehyde compound represented by formula (a) with a compound represented by formula (b) in the presence of a base (sodium hydroxide, potassium hydroxide, etc.), formula (c) is obtained. The intermediate represented is obtained. The reaction is carried out in a solvent at a temperature of 10-80°C. As the solvent, for example, dimethylformamide, dimethyl sulfoxide, etc. can be used. Then, this intermediate compound (c) is reacted with a hydrazine compound represented by the formula (d) under acidic conditions with the addition of acetic acid or the like to obtain the compound (1) of the present invention. This reaction can be carried out in the same solvent as above at a temperature of room temperature to 80°C.

The photosensitive layer in the present invention has the general formula (1
) Contains one or more compounds represented by: 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 general formula (1) and a binder resin, and a charge-generating layer and a charge-transporting layer are laminated. 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 type electrophotographic photoreceptor, a charge generation layer containing a charge generation material is formed on a conductive base material, and a charge transport material having the above general formula is formed on this charge generation layer. A charge transport layer containing the represented 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, perylene compounds,
Examples include indigo compounds, triphenylmethane compounds, threne compounds, toluidine compounds, pyrazoline compounds, perylene compounds, quinacridone compounds, and pyrrolopyrrole compounds. These charge generating materials can be used alone or in combination of two or more.

[0028] 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.

[0030] Examples of the solvent for dissolving the charge generating material, charge transporting material and 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 above 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. As the conductive substrate,
For example, single metals such as aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, brass, plastic materials on which the above metals are vapor-deposited or laminated, and iodide. Examples include glass coated with aluminum, tin oxide, indium oxide, etc.

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).

[0033] 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 (1) (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 10 to 500 parts, especially 25 to 2 parts, of the compound represented by the above general formula is added to 100 parts of the binder resin so that it can be easily transported.
Preferably, it is used in a proportion of 0.00 parts.

Further, 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 generating layer and a charge transporting layer is formed by a coating method, the charge generating material or the charge transporting material and the binder resin are coated 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.

[0036]

[Examples] The present invention will be explained in detail below with reference to Examples and Comparative Examples. Example 1 <Synthesis of the compound represented by the above formula (5)> The following formula (1
For 27.7 g of the aldehyde compound represented by 7),
27.1 g of the compound represented by the following formula (18) was heated at 50°C in dimethylformamide in the presence of sodium hydroxide.
The mixture was allowed to react for 4 hours.

[0037]

[Chemical formula 9]

After the product is isolated and purified by conventional methods,
Diphenylhydrazine (C6 H5)2 N-NH2
The compound was reacted with 10 g of the above compound in ethyl alcohol under acidic conditions at room temperature with stirring to obtain a compound represented by the above formula (5). Elemental analysis value: Calculated value (%) as C45H40N4
C84.87 H6.33 N8.80 actual value (%) C85.01 H6.30
N8.69 Each compound was produced in the same manner as in Example 1 using appropriate starting materials. The obtained compounds are as follows. Example 2 <Compound represented by formula (6)> Elemental analysis value: Calculated value (%) as C46H41N3
C86.89 H6.50 N6.61 actual value (%) C86.79 H6.52
N6.69 Example 3 <Compound represented by formula (8)> Elemental analysis value: Calculated value (%) as C49H39N3
C88.17 H6.20 N6.63 actual value (%) C88.06 H6.25
N6.69 Example 4 <Compound represented by formula (9)> Elemental analysis value: Calculated value (%) as C51H31N3
C88.79 H5.11 N6.09 actual value (%) C88.85 H5.07
N6.06 Example 5 <Compound represented by formula (10)> Elemental analysis value: Calculated value (%) as C48H40N3
C87.90 H5.69 N6.41 actual value (%) C87.98 H5.67
N6.35 Example 6 <Compound represented by formula (11)> Elemental analysis value: Calculated value (%) as C43H35N3
C86.98 H5.94 N7.08 actual value (%) C87.07 H5.90
N7.03 Example 7 <Compound represented by formula (15)> Elemental analysis value: Calculated value as C51H41N3 O2 (
%) C84.15 H5.68 N5.
77 Actual value (%) C84.09 H5.71
N5.80 Example 8 <Compound represented by formula (16)> Elemental analysis value: Calculated value (%) as C50H39N3
C88.07 H5.77 N6.16 actual value (%) C88.05 H5.72
N6.23 Examples 9 to 13 and Comparative Examples 1 and 2 (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 was mixed with zirconia beads (2
The mixture was dispersed for 2 hours using a paint shaker (mm diameter). The resulting dispersion was applied onto an aluminum sheet using a wire bar, dried at 100°C for 1 hour,
A charge generation layer of 0.5 μm was obtained. The charge generating materials used are shown in Tables 1 and 2. In these tables, charge generating materials A, B and C have the following formulas (A) and (B
) and (C).

[0039]

[Chemical formula 10]

[0040] On this charge generation layer, 1 part of a charge transport material and 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 9 to 13 are shown in Tables 1 and 2 by the compound numbers shown in the specific examples above. Further, charge transport materials I and II used in Comparative Examples 1 and 2 refer to compounds represented by the following formulas (I) to (II), respectively.

[0041]

[Chemical formula 11]

Examples 14 to 16 and Comparative Examples 3 and 4 (single-layer 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). . 50% of a tetrahydrofuran solution of polycarbonate resin ("Z-300" manufactured by Mitsubishi Gas Chemical Co., Ltd.) with a solid content of 20% by weight was added to the obtained dispersion.
1 part and 10 parts of charge transport material were added and dispersion continued for an additional hour. The resulting dispersion was applied onto an aluminum sheet using a wire bar, dried at 100°C for 1 hour,
A 20 μm photosensitive layer was obtained. The charge generating materials and charge transporting materials used are shown in Tables 1 and 2 by numbers attached to their respective chemical structural formulas, as in the above examples.

(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 9 to 16 are shown in Table 1, and the test results of Comparative Examples 1 to 4 are shown in Table 2.

[0045]

[Table 1]

[0046]

[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.

[0048]

[Effects of the Invention] As described above, the electrophotographic photoreceptor using the hydrazone compound of the present invention has excellent charging ability and sensitivity, and the hydrazone compound also has high compatibility with the binder resin. Therefore, it is possible to obtain a uniform photosensitive layer, and it also has the advantage of being highly flexible.

Claims (2)

[Claims] Claim 1: General formula (1): [Formula 1] (wherein R1 and R2 are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom; Any of the aryl groups may have a substituent; Ar1
, Ar2, Ar3 and Ar4 are the same or different and represent an alkyl group, an aryl group, a fused polycyclic group or a heterocyclic group, and any of these groups may have a substituent, and Ar1, Ar2 and Ar3 and Ar4
may each form a ring; X represents a residue that forms a condensed ring with the benzene ring, and may have a substituent; m and n represent 0, 1 or 2; However, m
and n must not be 0 at the same time. ) A hydrazone compound represented by 2. An electrophotographic photoreceptor characterized in that a photosensitive layer containing a hydrazone compound represented by the following general formula (1) is provided on a conductive substrate. [Formula 2] (In the formula, R1 and R2 are the same or different and represent a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or a halogen atom, and each of the alkyl group, alkoxy group, and aryl group has a substituent. May be; Ar1
, Ar2, Ar3 and Ar4 are the same or different and represent an alkyl group, an aryl group, a fused polycyclic group or a heterocyclic group, and any of these groups may have a substituent, and Ar1, Ar2 and Ar3 and Ar4
may each form a ring; X represents a residue that forms a condensed ring with the benzene ring, and may have a substituent; m and n represent 0 or 1; However, m and n must not be 0 at the same time. )