JPH04292663A - Hydrazone-based compound and photosensitive unit using the same - Google Patents

Abstract

PURPOSE:To obtain a new compound, excellent in sensitivity, repeating characteristics and charge transporting ability of photosensitive units and useful as a charge transporting material, etc. CONSTITUTION:A compound expressed by formula I [R<1> to R<6> are H, alkyl, alkoxy, aralkyl or aryl; Ar<1> to Ar<6> are H, alkyl, aryl, aralkyl or heterocyclic ring; (m) and (n) are 0 or 1, provided that Ar<1> to Ar<6> should not simultaneously be H], e.g. a compound expressed by formula II. Furthermore, the compound expressed by formula I is obtained by reaction an aldehyde compound expressed by formula III with a compound expressed by formula IV in a molar amount of 2 times in the presence of a base such as sodium hydroxide, providing an intermediate having a stilbene structure and reacting the resultant intermediate with a hydrazine-based compound expressed by the formula (Ar)2-N-NH2 in a solvent such as DMF under acidic conditions in which acetic acid, etc., are added. A photosensitive unit having a photosensitive layer containing the aforementioned compound is excellent in sensitivity and repeating characteristics.

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 a 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 and commercialized as charge transport materials, and for example, hydrazone compounds disclosed in JP-A-1-298364 and JP-A-2-210451 are known.

[0005]

However, conventional charge transport materials have the drawback of insufficient sensitivity and repeatability. An object of the present invention is to solve such technical problems and provide a hydrazone compound that is highly sensitive and has excellent repeatability, and a photoreceptor using the same.

[0006]

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

[0007]

[Chemical formula 3]

(In the formula, R1, R2, R3, R4
, R5 and R6 are the same or different hydrogen atoms,
An alkyl group, an alkoxy group, an aralkyl group, or an aryl group, and each of the alkyl group, alkoxy group, aralkyl group, and aryl group may have a substituent; Ar1, Ar2, Ar3, Ar4, Ar5
and Ar6 are the same or different and are a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and each of the alkyl group, aryl group, aralkyl group, and heterocyclic group may have a substituent; l, m and n represent 0 or 1.

[0009] However, Ar1, Ar2, Ar3, A
r4, Ar5 and Ar6 must not be hydrogen atoms 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.

Therefore, the photosensitive member 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 body has excellent sensitivity and charging ability, and high repeatability. 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, hexyloxy group, etc. Examples of the aryl group include phenyl group, naphthyl group, anthryl group, and phenanthryl 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 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.

[0013] Examples of substituents that may be substituted on the above groups include a halogen atom, an amino group, a hydroxyl group, a carboxyl group that may be esterified, a cyano group, a C1
-C6 alkyl group, C1 -C6 alkoxy group,
Examples include a C2-C6 alkenyl group that may have an aryl group. Two or more substituents may be bonded together, or two substituents may form a ring.

[0014] 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]

[C4]

[0016]

[C5]

[0017]

[C6]

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

[0019]

[C7]

(In the formula, R1, R2, R3, R4
, R5, R6, l, m and n are the same as above, each A
r is the above-mentioned Ar1, Ar2, Ar3, Ar, respectively.
4, Ar5 and Ar6. R7
is a lower alkyl group. ) That is, the aldehyde compound represented by formula (a) is reacted with twice the molar amount of the compound represented by formula (b) in the presence of a base (sodium hydroxide, potassium hydroxide, etc.). , and two of the three aldehyde groups to obtain an intermediate represented by formula (c) having a stilbene structure. The reaction is carried out in a solvent at a temperature of 0 to 120°C. As the solvent, for example, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, etc. can be used. Then, this intermediate compound (c) is given the formula (d
) A hydrazine compound represented by the following is reacted 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 120°C, and proceeds rapidly and almost quantitatively.

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 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 this charge generation layer. What is necessary is to form a charge transport layer containing a compound. 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,
Examples include anthanthrone compounds, perylene compounds, 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.

[0023] 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.

[0025] 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 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 photoreceptor, the charge generation material and the binder resin that constitute the charge generation layer can be used in various ratios, but the charge generation material and the binder resin that constitute the charge generation layer can be used in various ratios. 5 to 500 parts of materials, especially 10 to 500 parts
Preferably, it is used in a proportion of 250 parts.

[0029] 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.

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 photoreceptor, the charge generating material is 2 to 20 parts, especially 3 to 15 parts, and the compound represented by the above general formula (charge transporting material) is 40 to 200 parts per 100 parts of the binder resin. ,
In particular, 50 to 150 parts is suitable. In addition, the thickness of the single-layer type photosensitive layer is 10 to 50 μm, especially 15 to 3 μm.
It is preferably about 0 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 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.

[0032]

[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 (2)> For 32.9 g of tri(4-formylphenyl)amine, the formula: C6
40.0 g of a compound represented by H5-CH2-PO(OCH3)2 was reacted in dimethylformamide at 80°C for 5 hours in the presence of sodium hydroxide. After the product was isolated and purified by a conventional method, it was reacted with 3.0 g of diphenylhydrazine (C6H5)2N-NH2 in ethyl alcohol under acidic conditions at 60°C to obtain the above formula (2
) was obtained. Elemental analysis value: Calculated value (%) as C47H27N3
C87.68 H5.79
N6.53 actual value (%) C87.74 H
5.84 N6.42 or less, 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 the above formula (3)> Elemental analysis value: Calculated value (%) as C59H45N3
C89.02 H5.70
N5.28 actual value (%) C88.93 H
5.75 N5.32 Example 3 <Compound represented by formula (4)> Elemental analysis value: Calculated value (%) as C66H53N3
C89.25 H6.02
N4.73 actual value (%) C89.32 H
6.01 N4.81 Example 4 <Compound represented by formula (8)> Elemental analysis value: Calculated value (%) as C61H49N3
C88.91 H5.99
N5.10 Actual value (%) C88.94 H
6.04 N5.02 Example 5 <Compound represented by formula (9)> Elemental analysis value: Calculated value (%) as C51H41N3
C88.02 H5.96
N6.04 actual value (%) C88.07 H
5.94 N6.01 Example 6 <Compound represented by formula (10)> Elemental analysis value: Calculated value (%) as C65H49N3
C89.52 H5.66
N4.82 actual value (%) C89.44 H
5.69 N4.87 Examples 7 to 11 and Comparative Examples 1 to 3 (laminated photosensitive layer) 2 parts of charge generating material,
Polyvinyl butyral resin (“S-” manufactured by Sekisui Chemical Co., Ltd.)
lecBM-5) and 120 parts of tetrahydrofuran were dispersed for 2 hours in a paint shaker using zirconia beads (2 mm diameter). The resulting dispersion was applied onto an aluminum sheet using a wire bar.
It was 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, A, B and C mean compounds represented by the following formulas (A), (B) and (C), respectively.

[0033]

[Chemical formula 8]

[0034] 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 7 to 11 are shown in Tables 1 and 2 by the compound numbers shown in the specific examples above. In addition, the charge transport materials I to III used in Comparative Examples 1 to 3 have the following formulas (I) to (II), respectively.
It means a compound represented by I).

[0035]

[Chemical formula 9]

Examples 12 to 14 and Comparative Examples 4 to 6 (single layer type photosensitive layer) 1 part of 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. In Tables 1 and 2, the charge-generating materials and charge-transporting materials used are represented by their respective chemical structural formula numbers, 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 7 to 14 are shown in Table 1, and the test results of Comparative Examples 1 to 6 are shown in Table 2.

[0039]

[Table 1]

[0040]

[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.

[0042]

[Effects of the Invention] As described above, according to the photoreceptor of the present invention,
Since a specific compound with excellent charge transporting ability is used as the charge transporting material, it has the effect of not only charging ability but also excellent sensitivity.

Claims (2)

[Claims] Claim 1: General formula (I): [Formula 1] (wherein, R1, R2, R3, R4, R5 and R6 are the same or different and are a hydrogen atom, an alkyl group,
represents an alkoxy group, an aralkyl group or an aryl group,
All of the alkyl group, alkoxy group, aralkyl group and aryl group may have a substituent; Ar1,
Ar2, Ar3, Ar4, Ar5 and Ar6
are the same or different and represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and each of the alkyl group, aryl group, aralkyl group, and heterocyclic group may have a substituent; l, m and n represent 0 or 1. However, Ar1, Ar2, Ar3, Ar
4, Ar5 and Ar6 must not be hydrogen atoms at the same time. ) A hydrazone compound represented by 2. A 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] (wherein R1, R2, R3, R4, R5 and R6 are the same or different and are hydrogen atoms, alkyl groups,
represents an alkoxy group, an aralkyl group or an aryl group,
All of the alkyl group, alkoxy group, aralkyl group and aryl group may have a substituent; Ar1,
Ar2, Ar3, Ar4, Ar5 and Ar6
are the same or different and represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group, and each of the alkyl group, aryl group, aralkyl group, and heterocyclic group may have a substituent; l, m and n represent 0 or 1. However, Ar1, Ar2, Ar3, Ar
4, Ar5 and Ar6 must not be hydrogen atoms at the same time. )