JP2968869B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member containing a novel hydrazone compound.

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2. Description of the Related Art Conventionally, inorganic photoconductive materials such as selenium, cadmium sulfide, zinc oxide and silicon have been known for electrophotographic photoreceptors, and have been widely studied and put to practical use. . While these inorganic materials have many advantages, they also have various disadvantages. For example, selenium has drawbacks in that production conditions are difficult, and crystallization is easily caused by heat and mechanical shock, and cadmium sulfide and zinc oxide have poor moisture resistance and durability. It has been pointed out that silicon is insufficient in chargeability and difficult to manufacture. In addition, selenium and cadmium sulfide have toxicity problems.

On the other hand, organic photoconductive materials have good film-forming properties, excellent flexibility, are lightweight, have good transparency, and are sensitive to a wide wavelength range by an appropriate sensitization method. Due to its advantages such as easy design of the body, its practical use is gradually attracting attention.

Incidentally, the photoreceptor used in the electrophotographic technology is generally required to have the following basic properties. That is, (1) high chargeability against corona discharge in a dark place, (2) little leakage (dark decay) of the obtained charge in a dark place, and (3) charge charge by light irradiation. Rapid dissipation (light decay) of (4)
For example, the residual charge after light irradiation is small.

However, many studies have been made on photoconductive polymers such as polyvinyl carbazole as organic photoconductive substances to date, but these have not always had sufficient film-forming properties, flexibility and adhesiveness. Also, it is difficult to say that the above-mentioned basic properties of the photoreceptor are sufficiently provided.

On the other hand, as for the organic low-molecular-weight photoconductive compound, a photoreceptor having excellent mechanical strength such as film property, adhesion and flexibility can be obtained by selecting a binder or the like used for photoreceptor formation. Although it can be obtained, it is difficult to find a compound that is suitable for retaining high-sensitivity properties.

In order to improve such a point, the carrier generation function and the carrier transport function are shared by different substances,
Organic photoreceptors having higher sensitivity characteristics have been developed. The feature of such a photoreceptor, which is called a function-separated type, is that a material suitable for each function can be selected from a wide range. Has been advanced.

[0008]

As described above, various improvements have been made in the preparation of an electrophotographic photoreceptor, but the basic properties and high durability required for the above-mentioned photoreceptor are required. Have not yet been obtained. SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor having high sensitivity, high durability, a high charging potential, and almost no reduction in sensitivity even when used repeatedly, and having a stable charging potential. It is.

[0009]

Means for Solving the Problems The present inventors have conducted research on a photoconductive substance having high sensitivity and high durability, and as a result, have found that the novel hydrazone compound represented by Chemical Formula 1 is effective. The present invention has been reached.

In the formula 1, R ¹ and R ² are an alkyl group, an aralkyl group, an aryl group or a heterocyclic group which may have a substituent, and R ³ and R ⁴ are a hydrogen atom, a halogen atom, a substituent alkyl group which may have a alkoxy group, an aralkyl group, an aryl group or a heterocyclic group, R ^5, R ⁶ is a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group, an aryl group And a heterocyclic group. R ⁵ and R ⁶ may combine to form a ring.

Where R¹, R^Two As a specific example,
Alkyl group such as benzyl group, ethyl group, benzyl group, β-phenyl
Aralkyl such as phenylethyl group and α-naphthylmethyl group
Phenyl, methoxyphenyl, methylphenyl
Aryl, chlorophenyl, naphthyl, etc.
Group, thienyl group, furyl group, pyridyl group, carbazolyl group
Heterocycle such as group Groups. R^Three, R^FourConcrete
Examples include hydrogen, fluorine, chlorine, bromine atoms
Halogen atoms such as
Kill groups, methoxy groups, alkoxy groups such as ethoxy groups,
Benzyl group, β-phenylethyl group, α-naphthylmethyl
Aralkyl groups such as phenyl, phenyl, methoxyphenyl
Group, methylphenyl group, chlorophenyl group, naphthyl
Groups such as aryl, thienyl, furyl, pyridyl
And heterocyclic groups such as carbazolyl group.
You. R^Five, R⁶Specific examples of a hydrogen atom, a methyl group,
Alkyl group such as ethyl group, benzyl group, β-phenyl
Aralkyl groups such as ethyl group, α-naphthylmethyl group,
Phenyl group, methoxyphenyl group, methylphenyl group,
Aryl groups such as chlorophenyl and naphthyl,
Multiple groups such as nil group, furyl group, pyridyl group, carbazolyl group, etc.
Elementary ring And R.^FiveAnd R⁶And combine
Specific examples of the ring formed by cyclopentene ring,
Cyclohexene ring, methylcyclohexene ring, phenyl
Cyclohexene ring, cycloheptene ring, indene ring,
Toxinindene ring, chloroindene ring, phenylthioi
Ring, dihydronaphthalene ring, dimethyldihydrona
Phthalene ring, acenaphthylene ring, phenalene ring, phena
Nthrene ring, dihydrothiophene ring, dihydrofuran
Ring, indole ring, N-phenylindole ring, etc.
Can be

Hereinafter, specific examples of the compound represented by Chemical Formula 1 are shown, but the present invention is not limited thereto.

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Next, a synthesis example will be specifically described. Synthesis Example 1 (Synthesis of Exemplified Compound 44) N- (p-bromophenyl) cyclopent [b] indole obtained by condensation of cyclopent [b] indole with 1-bromo-4-iodobenzene was converted to n-butyllithium. Then, it was converted into a formyl compound by a conventional method of reacting with DMF. The formyl body thus obtained (0.90
g) and N, N-diphenylhydrazine hydrochloride (0.91
g) was heated at reflux for 1.5 hours with ethanol (16 ml) and a catalytic amount of acetic acid. The product was collected by filtration and recrystallized from ethanol + ethyl acetate (1: 1). yield:
0.67 g Yield: 46% Melting point: 175.6-176.3 ° C

Synthesis Example 2 (Synthesis of Compound 57) N- (p-bromophenyl) tetrahydrocarbazole obtained by condensation of tetrahydrocarbazole and 1-bromo-4-iodobenzene was converted to n-butyllithium and then to DMF. The reaction was led into a formyl compound by a conventional method. The formyl body (0.70 g) thus obtained and N-
Methyl-N-phenylhydrazine (0.37 g) was heated at reflux for 1.5 hours at room temperature with ethanol (10 ml) and a catalytic amount of acetic acid. The product was collected by filtration and recrystallized from ethanol. Yield: 0.58 g Yield: 60% Melting point: 149.0-149.6 ° C

The electrophotographic photoreceptor of the present invention can be obtained by containing one kind or two or more kinds of the hydrazone compound represented by Chemical formula 1. Various types of photoconductors are known, and any of them can be used. For example, there is a support provided with a photosensitive layer comprising a known charge generating substance, the compound of the present invention, and a film-forming binder resin on a conductive support. Also, on the conductive support,
Laminated photoconductors having a charge generation layer composed of a charge generation substance and a binder resin and a charge transport layer composed of the compound of the present invention and a binder resin are also known. Either of the charge generation layer and the charge transport layer may be an upper layer. As a support for preparing a photoreceptor using the compound of the present invention, a metal drum,
A metal plate, paper subjected to conductive processing, a plastic film sheet, a drum-shaped or belt-shaped support, and the like are used.

The film-forming binder resin used for forming the photosensitive layer on the support includes various resins depending on the field of use. For example, the use of a photoreceptor for copying includes polystyrene resin, polyvinyl acetal resin, polysulfone resin, polycarbonate resin, polyester resin, polyphenylene oxide resin, polyarylate resin, acrylic resin, methacrylic resin, and phenoxy resin. Among these, polystyrene resin, polyvinyl acetal resin, polycarbonate resin, polyester resin, polyarylate resin, and the like are excellent in potential characteristics as a photoconductor. These resins can be used alone or as a mixture of two or more of them as a copolymer.

The content of these resins in the photosensitive layer is preferably 10 to 500% by weight based on the weight of the compound of the present invention.
0 to 150% by weight is more preferred.

Among these resins, tension, bending,
Some have weak mechanical strength such as compression. To improve this property, substances which impart plasticity can be added. Specifically, phthalic acid esters (eg, DOP, DOP
BP, etc.), phosphate esters (eg, TCP, TOP
Etc.), sebacic esters, adipic esters, nitrile rubbers, chlorinated hydrocarbons and the like. If these substances are added unnecessarily, they adversely affect the electrophotographic properties. Therefore, the ratio is preferably 20% or less based on the binder resin.

In addition, an antioxidant, an anti-curl agent and the like can be added as necessary to the photoreceptor.

Examples of the charge generating substance used in combination with the compound of the present invention include inorganic compounds such as selenium, selenium-tellurium and amorphous silicon, benzopyrylium,
Examples include pyrylium dyes such as benzothiapyrylium, cyanine dyes such as thiacyanine and oxacyanine, squarylium dyes, phthalocyanine pigments, anthranthrone pigments, indigo pigments, quinacridone pigments, and azo pigments.

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EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 1 part by weight of the azo pigment represented by the chemical formula (1) and 1 part by weight of a polyester resin (Vylon 200 manufactured by Toyobo) were mixed with 100 parts by weight of tetrahydrofuran, and dispersed together with glass beads for 2 hours using a paint conditioner. The dispersion thus obtained was applied on an aluminum-evaporated polyester using an applicator to form a charge generation layer having a thickness of about 0.2 μm. Next, the compound represented by Chemical formula 46 is mixed with a polyarylate resin (U-polymer manufactured by Unitika) at a weight ratio of 1: 1 to form a 10% solution using dichloroethane as a solvent. This solution was applied by an applicator to form a carrier transport layer having a dry film thickness of 20 μm. The laminated electrophotographic photoreceptor thus prepared is applied to an electrostatic recording test apparatus (SP-428 manufactured by Kawaguchi Electric).
Was used to evaluate the electrophotographic characteristics. Measurement conditions: applied voltage -6 KV, static No. 3 (turntable rotation speed mode). As a result, the amount of light half-exposure to white light during charging is
A very high sensitivity of 1.5 lux / sec was obtained.

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Further, the same apparatus was used to evaluate the characteristics with respect to repeated use in which charging-discharging (discharging light: irradiation with white light at 400 lux × 1 second) was performed in one cycle. 1000
The change in the charged potential due to the repetition of
The initial potential at the 1000th test was −710 V, compared to the initial potential at −720 V at the test test.

Examples 2 to 7 Laminated photoconductors were prepared in the same manner as in Example 1 except that the compounds shown in Table 1 were used instead of the compounds used in Example 1. Using this photoreceptor, under the same conditions as in Example 1, the light half-life exposure amount E1 / 2 (lux · sec) and the initial potential Vo (V) were measured after the first and 1000 repetitions. Table 1 shows the results.

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[Table 1]

Examples 8 to 14 Titanyloxyphthalocyanine was used as a charge generating substance. That is, 1 part by weight of this pigment and 1 part by weight of a polyester resin (Vylon 200 manufactured by Toyobo) were mixed with 100 parts by weight of tetrahydrofuran, and dispersed together with glass beads for 2 hours using a paint conditioner. The pigment dispersion thus obtained was applied on the same support as in Example 1 using an applicator to form a carrier generating layer. The thickness of this thin film was about 0.2 μ. Next, a carrier transport layer was formed in the same manner as in Example 1 using each of the exemplified compounds shown in Table 2 to prepare a laminated photoreceptor. This photoreceptor was evaluated under the same measurement conditions as in Example 1. The results are shown in Table 2.

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[Table 2]

Comparative Examples 1 and 2 A photoconductor was prepared in the same manner as in Example 1 except that Comparative Compounds 117 and 118 were used instead of the compounds used in Example 1, and the characteristics were evaluated. Table 3 shows the results.

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[Table 3]

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As is apparent from the above, according to the present invention, an electrophotographic photosensitive member having high sensitivity and high durability can be provided.

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──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-284149 (JP, A) JP-A-59-182459 (JP, A) JP-A-62-156663 (JP, A) JP-A-62-162 204262 (JP, A) JP-A-63-249150 (JP, A) JP-A-2-210452 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G03G 5/06

Claims (1)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a conductive support containing a hydrazone compound represented by the following formula 1. Embedded image (In the chemical formula 1, R ¹ and R ² represent an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group which may have a substituent, and R ³ and R ⁴ represent a hydrogen atom, a halogen atom, or a substituent. An optionally substituted alkyl group, an alkoxy group, an aralkyl group, an aryl group, or a heterocyclic group, R ⁵ and R ⁶ are a hydrogen atom, an alkyl group optionally having a substituent, an aralkyl group, an aryl group, And a ring group, wherein R ⁵ and R ⁶ may combine to form a ring.)