JP2561976B2 - Hydrazone compound and photoconductor using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, as an electrophotographic photosensitive member in an image forming apparatus such as a copying machine, a printer or a facsimile, an organic photosensitive member having excellent processability and economical efficiency and having a large degree of freedom in functional design has been widely used. The Carlson process is widely used to form a copied image using an electrophotographic photosensitive member. The Carlson process
A charging process for uniformly charging the photoconductor by corona discharge, an exposure process for exposing the charged photoconductor to a document image to form an electrostatic latent image corresponding to the document image, and a development process in which the electrostatic latent image contains toner. A developing step of developing with a developer to form a toner image,
It includes a transfer step of transferring the toner image to a base material such as paper, a fixing step of fixing the toner image transferred to the base material, and a cleaning step of removing the toner remaining on the photoconductor after the transfer step. There is. In the Carlson process, in order to form a high-quality image, it is required that the electrophotographic photosensitive member has excellent charging characteristics and photosensitive characteristics, and that the residual potential after exposure is low.

Conventionally, inorganic photoconductors such as selenium and cadmium sulfide have been known as electrophotographic photosensitive materials.
They are toxic and have the disadvantage of high production costs. Therefore, so-called organic electrophotographic photoreceptors using various organic substances instead of these inorganic substances have been proposed. Such an organic electrophotographic photoreceptor has a photosensitive layer composed of a charge generation material that generates a charge upon exposure and a charge transport material having a function of transporting the generated charge.

In order to satisfy various conditions desired for such an organic electrophotographic photosensitive member, it is necessary to appropriately select these charge generating material and charge transporting material. As the charge transport material, various organic compounds have been proposed and commercialized, for example, JP-A-58-131954, JP-A-1-298364 and JP-A-2-210.
The hydrazone compound disclosed in Japanese Patent No. 451 is known.

[0005]

However, the conventional charge transport material has a disadvantage that the sensitivity and the repetition characteristics are not sufficient. An object of the present invention is to solve such technical problems and to provide a hydrazone compound having high sensitivity and excellent repeatability, and an electrophotographic photoreceptor using the same.

[0006]

Means and Actions for Solving the Problems The hydrazone compound of the present invention for achieving the above-mentioned object is represented by the general formula:
(I):

[0007]

Embedded image

(In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and are a hydrogen atom, an alkyl group,
An alkoxy group, an aralkyl group or an aryl group,
Any of the alkyl group, alkoxy group, aralkyl group and aryl group may have a substituent; Ar ¹ , A
r ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ are the same or different and each is a hydrogen atom, an alkyl group, an aralkyl group, an aryl group or a heterocyclic group, and the alkyl group, the aralkyl group, the aryl group and the heterocyclic group are Any of them may have a substituent; l, m and n represent 0 or 1.

However, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ ,
Ar ⁵ and Ar ⁶ must not be hydrogen atoms at the same time. ) Is represented. The hydrazone compound of the present invention is effective as a charge transport material, particularly a hole transport material, and has a higher hole mobility than charge transport materials such as conventionally known hydrazone compounds.

Therefore, the photoconductor of the present invention is characterized in that a photoconductive layer containing a hydrazone compound represented by the above general formula (1) is provided on a conductive substrate. The body has excellent sensitivity and chargeability, and has 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 a methoxy group, an ethoxy group, an isopropoxy group, a butoxy group, a t-butoxy group and a hexyloxy group.

As the aryl group, for example, a phenyl group,
Examples thereof include naphthyl group, anthryl group and phenanthryl group. Examples of the aralkyl group include a benzyl group,
Examples thereof include α-phenethyl group, β-phenethyl group, 3-phenylpropyl group, benzhydryl group and trityl group.

Examples of the heterocyclic group include a 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, piperidyl group, piperidino group, 3-morpholinyl Group, morpholino group, thiazolyl group and the like.

Further, a substituent which may be substituted on the above group
For example, halogen atom, amino group, hydroxyl group, ester
Optionally carboxylic group, cyano group, C₁
-C ₆Alkyl group, C₁-C₆Alkoxy group, aryl
C which may have a group₂-C₆Such as an alkenyl group
You can Two or more substituents may be substituted, or
Two other substituents may form a ring.

Further, Ar ¹ and Ar ² or Ar ³ and Ar
⁴ may together form a ring, and examples of such a ring include carbazole and the like. The following can be illustrated as specific compounds of the hydrazone compound represented by the above general formula.

[0016]

[Chemical 4]

[0017]

Embedded image

[0018]

[Chemical 6]

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

[0020]

[Chemical 7]

(Wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ ,
R ⁶ , l, m and n are the same as above, and each Ar is Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and A, respectively.
represents any one of r ⁶ and R ⁷ is a lower alkyl group. ) That is, the compound represented by the formula (b) is reacted with the aldehyde compound represented by the formula (a) in an equimolar amount and in the presence of a base (sodium hydroxide, potassium hydroxide, etc.), An intermediate represented by the formula (c) having a stilbene structure is obtained. 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, the intermediate compound (c) is reacted with the hydrazine compound represented by the formula (d) under acidic condition with addition of acetic acid or the like to obtain the compound (1 ′) of the present invention. The hydrazine compound (d) is used in a two-fold molar amount with respect to the compound (c). This reaction can be carried out in a solvent similar to the 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)
It contains one or more compounds represented by. The photosensitive layer in the present invention is a charge generating material, a single layer type of a mixture of a compound represented by the general formula (1) which is a charge transporting material and a binder resin, and a charge generating layer and a charge transporting layer are laminated. There is a laminated type, but the photosensitive layer of the present invention can be applied to any of them.

In order to obtain a laminated type photoreceptor, a charge generating layer containing a charge generating material is formed on a conductive base material, and on the charge generating layer, a charge transporting material represented by the above general formula is used. The charge transport layer containing the compound may be formed. Alternatively, the stacking order may be reversed, and the charge generation layer may be provided on the charge transport layer. As the charge generation material,
Conventionally used selenium, selenium-tellurium, selenium-arsenic, amorphous silicon, pyrylium salt, azo compounds, disazo compounds, phthalocyanine compounds, ansanthrone compounds, perylene compounds, indigo compounds, triphenylmethane Examples thereof include system compounds, threnic compounds, toluidine compounds, pyrazoline compounds, perylene compounds, quinacridone compounds, and pyrrolopyrrole compounds. These charge generating materials are 1
One kind or a mixture of two or more kinds can be used.

The compound represented by the above general formula which is a charge transport material can be used in combination with other conventionally known charge transport materials. Examples of conventionally known charge transport materials include 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 thereof include nitrogen-containing cyclic compounds such as compounds and condensed polycyclic compounds. In the case where a charge transporting material having a film forming property such as polyvinyl carbazole is used, a binder resin is not necessarily required.

As the binder resin, various resins can be used, for example, a styrene polymer, a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, a styrene-maleic acid copolymer, an acrylic copolymer. Coal, 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, Thermoplastic resins such as polyarylate, polysulfone, diallyl phthalate resin, ketone resin, polyvinylvinyl butyral resin, and polyether resin, silicone resin, epoxy resin, other crosslinkable thermosetting resin, epoxy acrylate, urethane-acrylate How such photocurable resins. These binder resins can be used alone or in combination of two or more.

Further, as a solvent for dissolving the charge generating material, the charge transporting material and the binder resin to prepare a coating solution, for example, alcohols such as methanol, ethanol, isopropanol, butanol, n-hexane, octane and cyclohexane are used. Aliphatic hydrocarbons such as benzene, toluene, xylene etc., aromatic hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride, chlorobenzene etc., dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether etc. Ethers, acetone, methyl ethyl ketone, cyclohexanone and other ketones, ethyl acetate, methyl acetate and other esters, dimethylformaldehyde, dimethylformamide, dimethyl Sulfoxide and the like.
These solvents can be used alone or in combination of two or more.

Further, in order to improve the sensitivity of the charge generating layer, known sensitizers such as terphenyl, halonaphthoquinones and acenaphthylene may be used together with the above charge generating material. Further, a surfactant, a leveling agent, etc. may be used to improve the dispersibility of the charge transporting material or the charge generating material and the dyeing property.

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

The conductive substrate may be in the form of a sheet, a drum or the like, as long as the substrate itself has conductivity or the surface of the substrate has conductivity. Also,
The substrate preferably has a sufficient mechanical strength when used. In the multi-layer type photoconductor, the charge generating material and the binder resin which constitute the charge generating layer can be used in various ratios, but the charge generating material is added to 100 parts of the binder resin (weight part, the same applies hereinafter). Material 5 to 500 parts, especially 10
It is preferably used at a ratio of 250 parts.

The charge generation layer may have an appropriate film thickness, but is 0.01 to 5 μm, particularly 0.1 to 3 μm.
It is preferable that the thickness is about m. The compound (charge-transporting material) represented by the above general formula (1) constituting the charge-transporting layer and the binder resin can be used in various ratios, but the charge generated in the charge-generating layer by light irradiation can be used. 10 to 500 parts, especially 25 to 20 parts by weight of the compound represented by the above general formula, relative to 100 parts of the binder resin, so that it can be easily transported.
It is preferably used in a ratio of 0 part.

The charge transport layer is preferably formed to have a thickness of 2 to 100 μm, particularly 5 to 30 μm. In the single-layer type photoreceptor, the charge generating material is 2 to 20 parts, particularly 3 to 15 parts, and the compound represented by the above general formula (charge transporting material) is 40 to 200 parts based on 100 parts of the binder resin. ,
Particularly, it is suitable that the amount is 50 to 150 parts. 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 the photosensitive layer including the charge generating layer and the charge transporting layer is formed by a coating means, the charge generating material or the charge transporting material and the binder resin are formed by a conventionally known method such as a roll mill, a ball mill, an attritor, or the like. A coating liquid is prepared using a paint shaker, an ultrasonic disperser or the like.

[0033]

The present invention will be described in detail below with reference to examples and comparative examples. Example 1 <Synthesis of Compound Represented by Formula (2) above> Represented by the formula: C ₆ H ₅ —CH ₂ —PO (OCH ₃ ) ₂ with respect to 32.9 g of tri (4-formylphenyl) amine. 20.0 g of the obtained compound was reacted in dimethylsulfoxide at 80 ° C. for 3 hours in the presence of sodium hydroxide. The product was isolated and purified by a conventional method, and then reacted with 6.0 g of diphenylhydrazine (C ₆ H ₅ ) ₂ N—NH ₂ in ethyl alcohol at 60 ° C. under acidic conditions to obtain the above compound.
A compound represented by (2) was obtained. Elemental analysis value: C ₄₆ H ₄₁ N
Calculated as ₅ (%) C83.22 H6.23 N10.55 Measured value (%) C83.37 H6.16 N10.47 Hereinafter, each compound was produced in the same manner as in Example 1 using appropriate starting materials. did. The obtained compounds are as follows. Example 2 <Compound represented by the above formula (3)> Elemental analysis value: calculated value as C ₅₈ H ₄₅ N ₅ (%) C85.79 H5.58 N8.63 measured value (%) C85.66 H5. 63 N8.71 Example 3 <Compound represented by formula (4)> Elemental analysis value: calculated value as C ₆₉ H ₅₅ N ₅ (%) C86.85 H5.81 N7.34 measured value (%) C86. 83 H5.78 N7.39 Example 4 <Compound represented by formula (8)> Elemental analysis value: Calculated value (%) as C ₆₀ H ₄₉ N ₅ C85.78 H5.88 N8.34 Measured value (%) ) C85.83 H5.95 N8.22 example 5 <compound (9)> elemental analysis: C ₆₀ H ₄₇ N calculated ₅ (%) C85.99 H5.65 N8.36 Found value (%) C86.10 H5.61 N8.29 example 6 <compound (10)> elemental analysis: calculated _{C 70 H 53 N 5 (%} ) C87.19 H5.54 N7 .27 measured value (%) C87.12 H5.52 N7.36 Examples 7 to 11 and Comparative Examples 1 to 3 (multilayer type feeling) Layer) 2 parts of the charge generating material, 1 part of polyvinyl butyral resin (“S-lecBM-5” manufactured by Sekisui Chemical Co., Ltd.), and 120 parts of tetrahydrofuran are dispersed with a paint shaker using zirconia beads (2 mm diameter) for 2 hours. Let The obtained dispersion was applied on an aluminum sheet using a wire bar, and dried at 100 ° C. for 1 hour to obtain a 0.5 μm charge generation layer. 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.

[0034]

Embedded image

On the charge generation layer, 1 part of a charge transport material and a polycarbonate resin (“Z-30 manufactured by Mitsubishi Gas Chemical Co., Inc.”
0 ") A solution prepared by dissolving 1 part in 9 parts of toluene was applied by a wire bar, and dried at 100 ° C. for 1 hour to obtain a 22 μm charge transport layer. The charge-transporting materials used in Examples 7 to 11 are shown in Tables 1 and 2 by the numbers of the compounds shown in the above specific examples. The charge transport materials I to III used in Comparative Examples 1 to 3 are represented by the following formulas (I) to (II
I) means a compound represented by the formula.

[0036]

[Chemical 9]

Examples 12 to 14 and Comparative Examples 4 to 6 (single layer type photosensitive layer) 1 part of the charge generating agent and 60 parts of tetrahydrofuran were dispersed for 2 hours on a paint shaker using zirconia beads (2 mm diameter). . The obtained dispersion has a solid content of 2
50 parts of a 0 wt% polycarbonate resin (“Z-300” manufactured by Mitsubishi Gas Chemical Co., Inc.) solution in tetrahydrofuran and 10 parts of a charge transport material were added, and the dispersion was further continued for 1 hour. The obtained dispersion is applied onto an aluminum sheet with a wire bar and dried at 100 ° C. for 1 hour to give 20 μm.
m photosensitive layer was obtained. The charge generating materials and charge transporting materials used are shown in Tables 1 and 2 by the numbers of their chemical structural formulas as in the above examples.

(Evaluation test) The surface potential, half-exposure amount (E _1/2 ) and residual potential of the photoconductors obtained in each of the examples and comparative examples were evaluated by an evaluation tester (“EPA8100” manufactured by Kawaguchi Electric Co., Ltd.).
It was measured at. The measurement conditions are as follows. Light intensity: 50 lux Exposure intensity: 1/15 sec Surface potential: (±) The flowing current was adjusted so as to be around 700 V. Light source: Tungsten lamp Static elimination: 200 lux Residual potential measurement: Measurement started 0.2 seconds after the start of exposure.

Table 1 shows the test results of Examples 7 to 14, and Table 2 shows the test results of Comparative Examples 1 to 6, respectively.

[0040]

[Table 1]

[0041]

[Table 2]

From the results of these tests, the surface potentials of the photosensitive layers of each Example are almost the same as those of the conventional photoconductor (Comparative Example), but the half-exposure amount and the residual potential are excellent, and the sensitivity is remarkable. You can see that it has been improved.

[0043]

As described above, according to the photoreceptor of the present invention,
Since the specific compound having excellent charge transporting ability is used as the charge transporting material, it has an effect that it has excellent charging ability as well as sensitivity.

Claims (2)

(57) [Claims] 1. General formula (I): (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group or an aryl group, and an alkyl group, an alkoxy group, an aralkyl group. Both the group and the aryl group may have a substituent; Ar ¹ , Ar ² and A
r ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ are the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group or a heterocyclic group, and the alkyl group, the aralkyl group, the aryl group and the heterocyclic group are all substituted. It may have a group; l, m and n represent 0 or 1. However, Ar
¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ cannot be hydrogen atoms at the same time. ) A hydrazone compound represented by. 2. A photosensitive member comprising a conductive layer and a photosensitive layer containing a hydrazone compound represented by the following general formula (1) provided on the conductive substrate. Embedded image (In the formula, R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group, an aralkyl group or an aryl group, and an alkyl group, an alkoxy group, an aralkyl group. Both the group and the aryl group may have a substituent; Ar ¹ , Ar ² and A
r ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ are the same or different and each represents a hydrogen atom, an alkyl group, an aralkyl group, an aryl group or a heterocyclic group, and the alkyl group, the aralkyl group, the aryl group and the heterocyclic group are all substituted. It may have a group; l, m and n represent 0 or 1. However, Ar
¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ cannot be hydrogen atoms at the same time. )