JPH0720647A - Electrophotographic photoreceptor - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an electrophotographic photoreceptor having high sensitivity and high durability. [Structure] As a photoconductive substance on a conductive support,
Alternatively, the spiro compound represented by Chemical formula 2 is contained. [Chemical 1] [Chemical 2] In the chemical formulas ¹ and 2, Z is an atomic group necessary for forming a carbocycle or a heterocycle which may have a substituent, R ^{1 to} R ^1.
7 is a hydrogen atom, an alkyl group which may have a substituent,
An aralkyl group, an aryl group, or a heterocyclic group, R ⁸ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, or an alkoxy group. R ⁴ and R ⁵ , and R ⁶ and R ⁷ may form a ring.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor containing a novel spiro compound.

[0002]

2. Description of the Related Art Inorganic photoconductive substances such as selenium, cadmium sulfide, zinc oxide, and silicon have been conventionally known for electrophotographic photoreceptors, and have been widely studied and put into practical use. . While these inorganic materials have many advantages, they also have various drawbacks. For example, selenium has drawbacks that it is difficult to manufacture under conditions and is easily crystallized by heat or mechanical impact, and cadmium sulfide and zinc oxide have poor moisture resistance and durability. It has been pointed out that silicon has insufficient chargeability and is 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, light weight, good transparency, and are sensitized to a wide range of wavelengths by a suitable sensitizing method. Because of its advantages such as easy body design, its practical application is gradually gaining attention.

By the way, the photoconductor used in the electrophotographic technique is generally required to have the following basic properties. That is, (1) high chargeability against corona discharge in the dark, (2) little leakage (dark decay) of the obtained charged charge in the dark, and (3) charge charging by light irradiation. Dissipation of light (light attenuation) is rapid, (4)
For example, the residual charge after light irradiation is small.

However, much research has been conducted on photoconductive polymers such as polyvinylcarbazole as an organic photoconductive substance to date, but these are not always sufficient in film formability, flexibility and adhesiveness. Also, it cannot be said that the photoconductor has the basic properties sufficiently.

On the other hand, regarding the organic low-molecular-weight photoconductive compound, by selecting a binder or the like used for forming the photosensitive member, a photosensitive member excellent in mechanical strength such as film-forming property, adhesion and flexibility can be obtained. Although obtainable, it is difficult to find compounds suitable for retaining the highly sensitive 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 have been developed. The characteristic of such a photoconductor, which is called a function-separated type, is that materials suitable for each function can be selected from a wide range, and many studies have been carried out because a photoconductor having arbitrary performance can be easily prepared. Has been promoted.

[0008]

As described above, various improvements have been made in the preparation of electrophotographic photoconductors, but the basic properties and high durability required for the photoconductors listed above have been improved. There has not yet been obtained enough to satisfy the requirement of. An object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity and high durability, high charging potential, almost no deterioration in sensitivity even after repeated use, and stable charging potential. Is.

[0009]

Means for Solving the Problems As a result of research by the present inventors on a photoconductive substance having high sensitivity and high durability, the novel spiro compound shown in Chemical formula 1 or Chemical formula 2 is effective. The present invention has been completed and the present invention has been achieved.

In Chemical Formula 1 and Chemical Formula 2, Z is an atomic group necessary for forming a carbocycle or a heterocycle which may have a substituent, R ^{1 to} R ^{7 each} have a hydrogen atom and a substituent. Optionally, an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group, R ⁸ represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, or an alkoxy group. R ⁴ and R ⁵ ,
R ⁶ and R ⁷ may each form a ring.

Specific examples of the carbocycle or heterocycle formed by Z and one carbon atom include a cyclopentane ring, a cyclohexane ring, a methylcyclohexane ring,
Examples thereof include a phenylcyclohexane ring, a cycloheptane ring, an indane ring, a tetrahydronaphthalene ring, a tetrahydrothiophene ring, a tetrahydrofuran ring and a tetrahydropyran ring. Specific examples of R ^{1 to} R ⁷ include a hydrogen atom, an alkyl group such as a methyl group and an ethyl group,
Aralkyl group such as benzyl group, β-phenylethyl group, α-naphthylmethyl group, phenyl group, methoxyphenyl group, methylphenyl group, chlorophenyl group, aryl group such as naphthyl group, thienyl group, furyl group, pyridyl group, carbazolyl Heterocyclic groups such as groups can be mentioned. Specific examples of R ⁸ include halogen atoms such as hydrogen atom, fluorine atom, chlorine atom and bromine atom, alkyl groups such as methyl group, ethyl group and 2-methoxyethyl group, methoxy group and 2-ethoxyethoxy group. An alkoxy group can be mentioned.

Specific examples of the compounds represented by Chemical Formulas 1 and 2 are shown below, but the present invention is not limited thereto.

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[Chemical formula 22]

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[Chemical formula 23]

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[Chemical formula 24]

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[Chemical Formula 39]

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[Chemical 42]

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[Chemical formula 45]

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[Chemical 56]

Next, a synthesis example will be specifically described. Synthetic Example (Exemplified Compound 39) Acetylcyclohexane and N, N-diphenylhydrazine were reacted in a mixed solvent of DMF and acetic acid at room temperature for 20 hours to obtain a cyclized product. This product was catalytically hydrogenated according to a conventional method and then introduced into the formyl compound of Formula 57 by the Vilsmeier reaction. This formyl compound (3.05 g) and diethyl 2-naphthylmethylphosphonate (3.06 g) were dissolved in dimethoxyethane (25 ml), and potassium t was added at room temperature.
-Butoxide (1.23g) was added. After 2 hours, the reaction mixture was poured into water and the precipitate was collected by filtration. Recrystallisation from acetonitrile then toluene gave the title compound. Yield 2.76 g Yield 64% Melting point 138.8-140.6 ° C

[0068]

[Chemical 57]

The electrophotographic photosensitive member of the present invention can be obtained by containing one kind or two or more kinds of the spiro compound shown in Chemical formula 1 or Chemical formula 2. Various types of photoreceptors are known, and any of them can be used. For example, there is one in which a photosensitive layer comprising a known charge generating substance, the compound of the present invention, and a film-forming binder resin is provided on a conductive support. Further, there is also known a laminated type photoreceptor in which 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 provided on a conductive support. There is. Either the charge generation layer or the charge transport layer may be the upper layer. As a support for forming a photoreceptor using the compound of the present invention, a metal drum, a metal plate, a conductive processed paper, a sheet of plastic film, a drum-shaped or belt-shaped support, etc. are used. .

As the film-forming binder resin used for forming the photosensitive layer on those supports, various resins can be mentioned depending on the field of use. For example, in the application of photoconductor for copying, polystyrene resin, polyvinyl acetal resin, polysulfone resin, polycarbonate resin, polyester resin, polyphenylene oxide resin, polyarylate resin, acrylic resin, methacrylic resin, phenoxy resin and the like can be mentioned. Among these, polystyrene resin, polyvinyl acetal resin, polycarbonate resin, polyester resin, polyarylate resin and the like are excellent in potential characteristics as a photoreceptor. Further, these resins can be used alone or as a copolymer by mixing two or more kinds.

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

Some of these resins include tension, bending,
Some have weak mechanical strength such as compression. To improve this property, plasticizing agents can be added. Specifically, phthalate ester (for example, DOP, D
BP), phosphoric acid ester (eg TCP, TOP, etc.)
And so on. If these substances are added more than necessary, the electrophotographic characteristics are adversely affected, so the proportion thereof is preferably 20% or less relative to the binder resin.

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

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

[0075]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Example 1 1 part by weight of the azo pigment represented by the chemical formula 58 and 1 part by weight of a polyester resin (Vylon 200 manufactured by Toyobo) were mixed with 100 parts by weight of tetrahydrofuran, and the mixture was dispersed with glass beads for 2 hours by a paint conditioner device. The dispersion thus obtained was coated on an aluminum vapor-deposited polyester film with an applicator to form a charge generation layer having a thickness of about 0.2 μm. Next, the compound represented by Chemical formula 11 was mixed with a polyarylate resin (U-polymer manufactured by Unitika) at a weight ratio of 1: 1 to prepare a 10% solution using dichloroethane as a solvent, and the solution was formed on the film of the carrier generating substance. , And was coated with an applicator to form a carrier transport layer having a dry film thickness of 20 μm.

[0077]

[Chemical 58]

The electrophotographic characteristics of the multi-layer type photoconductor thus prepared were measured by an electrostatic recording tester (SP-42 manufactured by Kawaguchi Denki Co., Ltd.).
8) was used. The measurement conditions are: applied voltage -6KV,
The static No. 3 and irradiation light illuminance (white light) were 2lux. As a result, the charging potential was -820 V and the half-exposure amount was 1.5 lux.sec.

Next, this photosensitive member was attached to an aluminum drum element tube, and the repeating characteristics of charging exposure were evaluated by a drum photosensitive member evaluation device (Cynthia 90 manufactured by Gentec). The measurement conditions are: corona applied voltage -6.5k, process speed 160mm / sec, TCDD2 mode 5000.
It was charging and photo static elimination once. Photostatic elimination was performed using a tungsten lamp array. As a result, the initial charging potential −
It was found that the change was 820V and -25V after 5,000 times with respect to 850V and the residual potential of -15V, respectively, and the changes were extremely small.

Examples 2 to 11 Laminated photoreceptors 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, the light half exposure amount E1 / 2 (lux seconds) and the initial potential Vo (V) were measured under the same conditions as in Example 1 after the first and 5000th repetitions. The results are shown in Table 1.

[0081]

[Table 1]

Comparative Examples 1 and 2 A photoconductor was prepared in the same manner as in Example 1 except that Comparative Compounds 59 and 60 were used instead of the compound used in Example 1, and the characteristics thereof were evaluated. The results are shown in Table 2.

[0083]

[Chemical 57]

[0084]

[Chemical 58]

[0085]

[Table 2]

[0086]

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

Claims (1)

[Claims] 1. An electrophotographic photosensitive member comprising a conductive support and a spiro compound represented by the following Chemical Formula 1 or Chemical Formula 2 below. [Chemical 1] [Chemical 2] (In Chemical Formula 1 and Chemical Formula 2, Z is an atomic group necessary for forming a carbocycle or a heterocycle which may have a substituent, R ¹
To R ⁷ are a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group, an aryl group, or a heterocyclic group, R ⁸
Represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, or an alkoxy group. R ⁴ and R ⁵ , R ⁶ and R ⁷
May each form a ring. )