JPH10333343A - Electrophotographic organic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress cracking due to the sticking of fingerprints by regulating the variation of the sensitivity of an org. photoreceptor before and after immersion in polydimethylsiloxane for 1 hr to a specified value or below. SOLUTION: This electrophotographic org. photoreceptor has <=25% variation of the sensitivity to light having 780 nm wavelength and 0.6 μJ/cm<2> energy before and after immersion in polydimethylsiloxane for 1 hr. The photoreceptor contains an electric charge generating agent and an electric charge transferring agent in a bonding resin. It is preferably a single layer org. photoreceptor contg. an electric charge generating agent dispersed in a resin medium and is most preferably a single dispersion layer type photoreceptor contg. an electric charge transferring agent, in particular a hole transferring agent and an electric charge generating agent in a resin medium. The amt. or concn. of the electric charge transferring agent added is made as small or low as possible within the range in which the sensitivity is not substantially reduced. The electric charge transferring agent is excellent in oil resistance and the resin medium has a high glass transition temp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic organic photoreceptor used for an electrophotographic image forming apparatus, for example, an analog PPC, an optical printer, a facsimile, a digital PPC, etc. The present invention relates to an electrophotographic organic photoconductor in which body deterioration is effectively prevented.

[0002]

2. Description of the Related Art In electrophotographic image formation, a photoreceptor is uniformly charged and then image-exposed to form an electrostatic latent image. The electrostatic latent image is developed with toner, and the toner image is exposed to light. The image is transferred from the body to the transfer paper, and the toner image on the transfer paper is fixed to form an image.

As the electrophotographic photoreceptor, a selenium photoreceptor,
Various photoconductors such as a-silicon photoconductors and organic photoconductors are known, but organic photoconductors are superior in terms of manufacturing cost and adaptability to small copying machines, fax machines and printers. .

[0004] The organic photoreceptor includes a monodispersed layer type photoreceptor in which a charge transporting agent (CTM) and a charge generating agent (CGM) are dispersed in a resin medium and provided on a conductive substrate. There is known a laminated photoconductor provided with a charge generation layer and a charge transport layer.

[0005] These organic photoreceptors are generally mounted on an image forming apparatus in the form of a drum and used for image formation by electrophotography. However, it is necessary to eliminate a paper jam of transfer paper or to clean the periphery of the drum. Therefore, a structure in which a housing around a drum can be opened and closed is generally adopted. For this reason, at the time of manufacturing and assembling or maintenance of the image forming apparatus, the surface of the photoconductor may be apologized and touched, and the transfer of fingerprints to the surface of the photoconductor cracks the surface of the photoconductor, thereby obtaining a good image. That tended to be difficult.

In order to prevent the hand from touching the surface of the photoreceptor, a cover is already put on the drum when the housing around the drum or the transfer paper transport unit is open.

Further, in order to prevent cracking of the surface of the photosensitive layer even when the surface of the photosensitive member is touched, a surface protective layer is already provided on the photosensitive member.

[0008]

However, in the former configuration, when the housing around the drum and the transfer paper transport unit are opened, a mechanism for automatically covering the drum with a cover must be provided in the apparatus body or the process kit. Therefore, there is a disadvantage that the apparatus becomes complicated and the apparatus cost increases.

In the former configuration in which a surface protective layer is provided on the photoconductor, the productivity of the photoconductor drum is reduced and the manufacturing cost of the photoconductor drum is increased. Accumulates to reduce the electrophotographic properties and shorten the life of the photoreceptor.

Accordingly, it is an object of the present invention to provide an organic photosensitive drum which is prevented from being deteriorated due to fingerprint adhesion without providing a surface protective layer, so that a good image can be obtained without disposing a drum cover or the like. An object of the present invention is to provide an organic photoconductor drum for an image forming apparatus which can be obtained continuously and stably.

[0011]

According to the present invention, the rate of change in sensitivity to light having a wavelength of 780 nm and an energy of 0.6 μJ / cm ² before and after immersion in polydimethylsiloxane for one hour is 25% or less. Is provided.

[0012]

DETAILED DESCRIPTION OF THE INVENTION

[Action] The present inventors have conducted intensive studies on the cause of cracking on the surface of the photoconductor when the electrophotographic organic photoconductor is touched, and as a result, the following facts have been found. That is,
When a finger touches the surface of the organic photoreceptor, secretory fat such as a fingertip becomes a fingerprint and migrates to the photoreceptor surface, but the charge transport agent (CTM) in the photoreceptor dissolves in the fat and stains the surface. What comes out is the truth of cracking.

Furthermore, as a result of searching for an organic photoreceptor having resistance to cracking caused by fingerprint attachment, the rate of change in sensitivity to light having a wavelength of 780 nm and an energy of 0.6 μJ / cm ² before and after immersion in polydimethylsiloxane for 1 hour. Has been found to meet this purpose.

The characteristics of the organic photoreceptor considered in the present invention are the characteristics before and after immersion in polydimethylsiloxane for one hour, and the rate of change in sensitivity to light of a specific wavelength and specific energy. There is a close relationship with the occurrence of cracking due to the attachment of fingerprints to the organic photoreceptor.

See the example below. That is, the rate of change in sensitivity before and after immersion in polydimethylsiloxane for 1 hour is 2
If it exceeds 5%, cracking due to fingerprint attachment will occur, whereas cracking due to fingerprint attachment can be completely suppressed by suppressing this rate of change in sensitivity to 25% or less. .

Thus, according to the present invention, a good image can be obtained without providing a drum cover or the like by supplying an organic photoreceptor drum which is prevented from being deteriorated due to fingerprint adhesion without providing a surface protective layer. There is an advantage that it can be obtained continuously and stably.

[Electrophotographic Photoreceptor] The electrophotographic organic photoreceptor of the present invention has a rate of change in sensitivity to light having a wavelength of 780 nm and an energy of 0.6 μJ / cm ² of 25% or less before and after immersion in polydimethylsiloxane for 1 hour. There is something.

The electrophotographic photoreceptor to which the present invention is directed contains a charge generating agent and a charge transporting agent in a binder resin. The organic photoreceptor is preferably a single-layer organic photoreceptor in which a charge generating agent is dispersed in a resin medium, and contains a charge transporting agent, particularly a hole transporting agent and a charge generating agent, in the resin medium. Most preferably, it is a monodispersed layer type photoreceptor.

The photoreceptor of the present invention may be a laminated photoreceptor comprising a charge transport layer containing a charge transport agent and a charge generation layer containing a charge generator. In this case, the charge generation layer ( CGL) and a charge transport layer (CTL) are preferably stacked in this order.

In the present invention, the rate of change in sensitivity before and after immersion in polydimethylsiloxane of the organic photoreceptor for 1 hour is 25%.
In order to suppress the following, at least one of the following means,
Alternatively, two or more are adopted, but of course, the present invention is not limited to this case. (1). The addition amount or concentration of the charge transporting agent is made as low as possible without substantially lowering the sensitivity. (2). The kind of the charge transporting agent is also excellent in oil resistance. For example, in the case of an electron transporting agent, a naphthoquinone derivative is used. (3). As the resin medium, a resin medium having a high glass transition point, for example, a resin having a glass transition point of 100 ° C. or higher is used.

The above-mentioned means (1) is useful for minimizing spotting on the surface of the resin transport medium since the concentration of the charge transport agent in the resin medium is suppressed to a low level. Means (2) above is useful for minimizing spotting on the surface of the oil, since the solubility of the charge transport agent in the oil is reduced. The means (3) is useful for minimizing the occurrence of stains on the surface of the charge transporting agent, because the tendency of the resin medium to soften due to oil is suppressed.

Hereinafter, the structure of the organic photoreceptor will be described.

(A) Resin medium: The resin medium in which the charge transporting agent and the charge generating agent are dispersed includes a glass transition point (Tg).
Is preferably 100 ° C. or higher, especially polycarbonate.

Polycarbonate is a polycarbonate obtained by the reaction of bisphenols and phosgene,
More specifically, the following general formula (1):

Embedded image In the formula, R ₁ and R ₂ are a hydrogen atom or a lower alkyl group, and R ₁ and R ₂ may be linked together to form a cyclo ring such as a cyclohexane ring together with a bonding carbon atom. Polycarbonate derived from bisphenols and phosgene.

Examples of the starting bisphenols include:
2,2-bis (4-hydroxyphenyl) propane (bisphenol A), 2,2-bis (4-hydroxyphenyl) butane (bisphenol B), 1,1-bis (4
-Hydroxyphenyl) ethane, bis (4-, 3- or 2-hydroxyphenyl) methane (bisphenol F), 1,1-bis (4-hydroxyphenyl) cyclopentane, 1,1-bis (4-hydroxyphenyl) Cyclohexane (bisphenol Z), and the like.

The polycarbonate to be used preferably has a glass transition point of 100 ° C. or more from the above-mentioned viewpoints. It is excellent in workability and oil resistance. This type of polycarbonate can be obtained, in particular, as Panlite manufactured by Teijin Chemicals Limited, PCZ manufactured by Mitsubishi Gas Chemical Company, or the like.

This polycarbonate may be used alone, or may be used in a blend with other known resins for organic photoreceptors as long as the above-mentioned restrictions are satisfied.

(B) Charge generating agent: As the charge generating agent,
For example, selenium, selenium-tellurium, amorphous silicon, pyrylium salts, azo pigments, disazo pigments, anthanthrone pigments, phthalocyanine pigments, indico pigments, slen pigments, toluidine pigments, pyrazoline pigments, perylene pigments And quinacridone pigments and the like, and one kind or a mixture of two or more kinds is used so as to have an absorption wavelength region in a desired region.

Particularly preferred are the following phthalocyanine pigments, perylene pigments, bisazo pigments and the like. Examples of phthalocyanine pigments include metal-free phthalocyanine, aluminum phthalocyanine, vanadium phthalocyanine, cadmium phthalocyanine, antimony phthalocyanine, chromium phthalocyanine, copper 4-phthalocyanine, germanium phthalocyanine, iron phthalocyanine, chloroaluminum phthalocyanine, oxotitanyl phthalocyanine, chloroindium phthalocyanine, and chlorogallium. Examples include phthalocyanine, magnesium phthalocyanine, dialkyl phthalocyanine, tetramethyl phthalocyanine, tetraphenyl phthalocyanine, and the like. Also, the crystal form is α-type, β-type, γ-type, δ-type,
Any of ε-type, σ-type, x-type, and τ-type can be used.

Perylene pigments, in particular, of the general formula (2)

Embedded image In the formula, each of R ₃ and R ₄ is a substituted or unsubstituted alkyl group, cycloalkyl group, aryl group, alkaryl group, or aralkyl group having 18 or less carbon atoms. What is represented by Examples of the alkyl group include an ethyl group, a propyl group, a butyl group, a 2-ethylhexyl group, and the like.
Examples of the cycloalkyl group include a cyclohexyl group and the like; examples of the aryl group include a phenyl group and a naphthyl group; examples of the alkaryl group include a tolyl group, a xylyl group, and an ethylphenyl group; and an aralkyl group. Examples thereof include a benzyl group and a phenethyl group. Examples of the substituent include an alkoxy group and a halogen atom.

Bisazo pigments, especially the following formula (3)

Embedded image In the formula, A is a hydrogen atom or a substituted or unsubstituted alkyl group, aryl group or heterocyclic group, n is zero or 1, and Cp is a coupler residue. In the 3-position of the pyrazole ring, a substituted or unsubstituted alkyl group, directly or via a vinylidene group,
An aryl group or a heterocyclic group may be bonded, wherein the alkyl group includes methyl, ethyl, propyl,
Butyl, amyl group, and the like, and the aryl group includes phenyl, naphthyl, biphenyl, anthryl, phenanthryl, and fluorenyl group.The heterocyclic group includes nitrogen, oxygen, sulfur, or a combination thereof in the ring. A monocyclic or polycyclic saturated or unsaturated heterocyclic group such as thienyl, furyl, imidazolyl, pyrrolyl, pyrimidinyl, imidazole, pyrazinyl, pyrazolinyl, pyrrolidinyl, pyranyl,
Piperidyl group, piperazinyl group, morpholyl group, pyridyl group, pyrimidyl group, pyrrolidinyl group, pyrrolinyl group,
Examples include a benzofuryl group, a benzimidazolyl group, a benzofuranyl group, an indolyl group, a quinolyl group, a carbazolyl group, and a dibenzofuranyl group. These substituents include a lower alkyl group, a lower alkoxy group, an acyloxy group, a halogen atom such as chlor, a hydroxyl group, a nitrile group, a nitro group, an amino group, an amide group, an acyloxy group, a carboxyl group, and the like. On the other hand, equation (3)
The coupler residue in the above is not particularly limited as long as it is a residue of a coupler (azo coupling component) used in this type of azo pigment, such as a substituted or unsubstituted phenol, naphthol, or hydroxyl group-containing heterocyclic ring. The substituent may be a lower alkyl group, a lower alkoxy group, an aryl group, an acyloxy group,
Halogen atoms such as chlor, hydroxyl group, nitrile group, nitro group, amino group, amide group, acyloxy group,
And a carboxyl group.

(C) Charge-transporting agent: As the charge-transporting agent, a material satisfying the above-mentioned requirements is selected and used from any known electron-transporting or hole-transporting materials.
An example is as follows.

Examples of the electron transport agent include a paradiphenoquinone derivative, a benzoquinone derivative, a naphthoquinone derivative, tetracyanoethylene, tetracyanoquinodimethane, chloranil, bromoanil, 2,4,7-trinitro-9.
-Fluorenone, 2,4,5,7-tetranitro-9-
Electron-withdrawing substances such as fluorenone, 2,4,7-trinitro-9-dicyanomethylenefluorenone, 2,4,5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, and these electron-withdrawing substances Which have been polymerized.

Of these, naphthoquinone derivatives,
Paradiphenoquinone derivatives, particularly naphthoquinone derivatives, are preferred because they have excellent oil resistance and excellent electron transport properties.

The naphthoquinone derivative is represented by the following general formula (4)

Embedded image In the formula, R ^a represents an alkyl group which may have a substituent or an aryl group which may have a substituent, and R ^b represents an alkyl group which may have a substituent, also represents an aryl group or a group -O-R ^G. R ^G in the above groups represents an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl group which may have a substituent. Examples thereof include 2-t-butylcarbonyl-3-phenylnaphthoquinone, 2-t-butylcarbonyl-3-tolylnaphthoquinone, 2-t-butoxycarbonyl-3-phenylnaphthoquinone, and 2-isopropylcarbonyl-3. -Phenylnaphthoquinone, 2-t-butylcarbonyl-3-
Butylnaphthoquinone, 2-t-butylcarbonyl-3-
Xylylnaphthoquinone and the like.

As the paradiphenoquinone derivative, the following general formula (5):

Embedded image Where R ⁵ , R ⁶ , R ⁷ And R ⁸ Is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, or the like. R ⁵ , R ⁶ , R ⁷ And R ⁸ It preferably has a substituent of the asymmetric structure, R ⁵ , R ⁶ , R ⁷ And R ⁸ Of which
Preferably, two are lower alkyl groups and the other two are branched alkyl groups, cycloalkyl groups, aryl groups or aralkyl groups. Suitable examples thereof include, but are not limited to, 3,5-dimethyl-3 ′, 5′-di-t-.
Butyl diphenoquinone, 3,5-dimethoxy-3 ',
5′-di-tert-butyl diphenoquinone, 3,3′-dimethyl-5,5′-di-tert-butyl diphenoquinone, 3,5 ′
-Dimethyl-3 ', 5-di-tert-butyldiphenoquinone,
3,5,3 ′, 5′-tetramethyldiphenoquinone,
2,6,2 ′, 6′-tetra-tert-butyldiphenoquinone, 3,5,3 ′, 5′-tetraphenyldiphenoquinone, 3,5,3 ′, 5′-tetracyclohexyldiphenoquinone, These diphenoquinone derivatives are preferable because of their low molecular symmetry, small interaction between molecules, and excellent solubility.

On the other hand, as the hole transporting substance, for example, the following substances are known, and among them, those having excellent oil resistance and hole transporting property are used. Pyrene, N-
Ethyl carbazole, N-isopropyl carbazole,
N-methyl-N-phenylhydrazino-3-methylidene-9-carbazole, N, N-diphenylhydrazino-
3-methylidene-9-ethylcarbazole, N, N-diphenylhydrazino-3-methylidene-10-ethylphenothiazine, N, N-diphenylhydrazino-3-methylidene-10-ethylphenoxazine, p-Diethylaminobenzaldehyde-N, N-diphenylhydrazone, p-diethylaminobenzaldehyde-α-naphthyl-N-phenylhydrazone, p-pyrrolidinobenzaldehyde-N, N-diphenylhydrazone, 1,3,3
-Trimethylindolenine-ω-aldehyde-N, N-
Hydrazone salts such as diphenylhydrazone, p-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadizole, 1-phenyl- 3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazolin, 1- [quinonyl (2)]-3- (p-diethylaminostyryl) -5-
(P-diethylaminophenyl) pyrazoline, 1- [pyridyl (2)]-3- (p-diethylaminostyryl)
-5- (p-diethylaminophenyl) pyrazoline, 1
-[6-Methoxy-pyridyl (2)]-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazolin, 1- [pyridyl (3)]-3- (p
-Diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1- [repidyl (3)]-3
-(P-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, 1- [pyridyl (2)]-3- (p-diethylaminostyryl) -4-
Methyl-5- (p-diethylaminophenyl) pyrazoline, 1- [pyridyl (2)]-3- (α-methyl-p-
Pyrazolines such as diethylaminostyryl) -3- (p-diethylaminophenyl) pyrazoline, 1-phenyl-3- (p-diethylaminostyryl) -4-methyl-5- (p-diethylaminophenyl) pyrazoline and spiropyrazoline; -(P-diethylaminostyryl)
-3-diethylaminobenzoxazole, 2- (p-
Oxazole compounds such as diethylaminophenyl) -4- (p-dimethylaminophenyl) -5- (2-chlorophenyl) oxazole, thiazole compounds such as 2- (p-diethylaminostyryl) -6-diethylaminobenzothiazole, Bis (4-diethylamino-
Triary such as 2-methylphenyl) phenylmethane
Methane compound, 1,1-bis (4-N, N-diethylamino-2-methylphenyl) heptane, 1,1,
2,2-tetrakis (4-N, N-dimethylamino-2
Polyarylalkanes such as -methylphenyl) ethane, N, N'-diphenyl-N, N'-bis (methylphenyl) bendiben, N, N'-diphenyl-N, N '
-Bis (ethylphenyl) benzidine, N, N'-diphenyl-N, N'-bis (propylphenyl) benzidine, N, N'-diphenyl-N, N'-bis (butylphenyl) benzidine, N, N'- Bis (isopropylphenyl) benzidine, N, N'-diphenyl-N, N '
-Bis (secondary butylphenyl) benzidine, N, N '
-Diphenyl-N, N'-bis (tertiarybutylphenyl) benzidine, N, N'-diphenyl-N, N'-bis (2,4-dimethylphenyl) benziben, N, N '
Benzidine compounds such as -diphenyl-N, N'-bis (chlorophenyl) benzidine, phenylenediamine derivatives diaminonaphthalene derivatives diaminophenanthrene derivatives triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene,
Polyvinyl alicdin, poly-9-vinyl phenyl anthracene, pyrene-formaldehyde resin, ethyl carbazole formaldehyde resin.

As a preferable hole transporting agent, the following formula (6)

Embedded image In the formula, each of Ar ₁ , Ar ₂ , Ar ₃ and Ar ₄ is a substituted or unsubstituted aryl group, Y is a substituted or unsubstituted arylene group, and n is a number of 0 or 1. The aromatic amines represented, in particular, phenylenediamine derivatives, diaminonaphthalene derivatives and diaminophenanthrene derivatives are mentioned.

Further, as other suitable hole transporting agents, hydrazones, particularly the following formula (7)

Embedded image In the formula, each of Ar ₅ , Ar ₆ and Ar ₇ is a substituted or unsubstituted aryl group.

In the monodisperse photoreceptor used in the present invention, the charge generator (CGM) is used in an amount of 0.5 to 7 parts by weight, especially 1 to 5 parts by weight, per 100 parts by weight of the resin. And a charge transporting agent (CT
M) is 20 to 50 parts by weight per 100 parts by weight of the resin,
In particular, it is preferable to use an amount in the range of 25 to 45 parts by weight.
When the amount of the charge transporting agent is larger than the above range, cracking due to fingerprint adhesion tends to increase, while when the amount is smaller than the above range, sensitivity tends to decrease.

Further, from the viewpoint of sensitivity and the wide range of applications to enable reversal development, it is preferable to use an electron transporting agent (ET) and a hole transporting agent (HT) in combination. In this case, the weight ratio of ET: HT is 10: 1 to 1:10,
In particular, it is most preferably in the range of 2: 1 to 1: 5.

The composition for forming a photoreceptor used in the present invention includes:
Various additives known per se, such as antioxidants, radical scavengers, singlet quenchers, UV absorbers, softeners, surface modifiers, defoaming, as long as they do not adversely affect the electrophotographic properties. Agents, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, and the like.

When a sterically hindered phenolic antioxidant is added in an amount of 0.1 to 50% by weight based on the total solid content,
The durability of the photosensitive layer can be significantly improved without adversely affecting the electrophotographic properties.

(D) Conductive substrate: As the conductive substrate on which the photosensitive layer is provided, various conductive materials can be used.
For example, a simple metal such as aluminum, copper, tin, platinum, gold, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, indium, stainless steel, brass, or a plastic material on which the above metal is deposited or laminated, iodine Examples include glass coated with aluminum oxide, tin oxide, indium oxide, and the like. In the single-layer dispersion type photoreceptor used in the present invention, a normal aluminum tube, particularly a tube subjected to alumite treatment so as to have a thickness of 1 to 50 μm can be used.

(E) Preparation of photoreceptor: In order to form a monodispersed layer type photoreceptor, a charge generating material, a charge transporting agent and a binder resin are mixed with a conventionally known method such as a roll mill or a ball mill. It may be prepared by using an attritor, a paint shaker, an ultrasonic disperser, or the like, and may be applied and dried by a conventionally known application means. Although the thickness of the photosensitive layer is not particularly limited, it is generally 5 to 100 μm, particularly 10 to 40 μm.
It is desirable to provide within the range of m so as not to cause a decrease in sensitivity or an increase in residual potential.

As the solvent used for forming the coating solution, various organic solvents can be used, such as alcohols such as methanol, ethanol, isopropanol and butanol;
n-hexane, octane, aliphatic hydrocarbons such as cyclohexane, benzene, toluene, aromatic hydrocarbons such as xylene, dichloromethane, dichloroethane, carbon tetrachloride, halogenated hydrocarbons such as chlorobenzene, dimethyl ether, diethyl ether, tetrahydrofuran, Various solvents such as ethers such as 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; dimethylformamide and dimethyl sulfoxide; Used as a mixture. In general, the solid content of the coating solution is preferably 5 to 50%.

In the case of a laminated photoreceptor, the charge generating agent (CGM) is used in an amount of 30 per solid of the charge generating layer (CGL).
And the charge transporting agent (CTM) is present in an amount in the range of 20 to 50% by weight, in particular 25 to 50% by weight, per solid of the charge transporting layer (CTL). It may be contained in an amount in the range of from about 45% by weight to about 45% by weight. The components of each coating layer correspond to the components of the monodispersed layer type.

In the case of substrate / CGL / CTL photoreceptor, CG
L should generally be in the range of 0.1 to 2 μm,
The CTL is preferably provided within a range of 5 to 40 μm, particularly 10 to 30 μm.

[Electrophotography] In the electrophotography using the photoreceptor of the present invention, the organic photoreceptor is charged and exposed to form an electrostatic latent image. The method includes a step of developing with a developer as an essential component, a step of transferring the toner on the photoconductor onto a transfer material, and a step of removing the charge of the photoconductor after the transfer.

As the developer, a developer known per se is used, for example, a two-component magnetic developer comprising a magnetic carrier and a visible toner, a one-component magnetic toner, a one-component non-magnetic toner, and the like. Both are used.

The developing system may be a regular developing system or a reversal developing system.

[0052]

The present invention is further described by the following examples.

[Preparation of Photoreceptor] <Photoreceptor A> 5 parts by weight of an X-type metal-free phthalocyanine as a charge generator, and N, N, N ',
N'-tetrakis (3-methylphenyl) -9,10-
40 parts by weight of diaminophenanthrene and 2-t-butylcarbonyl-3-phenyl-1,4-phenylene as an electron transporting agent
40 parts by weight of naphthoquinone, 100 parts by weight of bisphenol Z-type polycarbonate as a binder, and 800 parts by weight of tetrahydrofuran as a solvent were further added and mixed and dispersed in a ball mill for 50 hours to prepare a coating solution for a single-layer type photosensitive layer. After applying the coating solution on the aluminum tube,
Hot-air drying at 00 ° C for 60 minutes to form a film with a thickness of 25 μm
Was prepared. <Photoconductor B> Single layer for electrophotography similar to Photoconductor A except that N, N, N ', N'-tetrakis (3-methylphenyl) -1,3-phenylenediamine is used as a hole transporting agent. A photoreceptor B was obtained. <Photoconductor C> 70 parts by weight of N, N, N ', N'-tetrakis (3-methylphenyl) -1,3-phenylenediamine as a hole transporting agent and 2-t-butylcarbonyl- as an electron transporting agent A single-layer electrophotographic photoconductor was prepared in the same manner as photoconductor A except that 50 parts by weight of 3-phenyl-1,4-naphthoquinone was added to obtain photoconductor C.

[Measurement Method of Photosensitive Member Sensitivity] Using a drum sensitivity tester manufactured by GENTEC, an applied voltage was applied to the surface of the photosensitive member to charge the surface to +700 V. 780 nm extracted from white light of a halogen lamp as an exposure light source using a band-pass filter, and a light intensity of 15 μW /
The surface of the photoreceptor was irradiated with monochromatic light of cm ² for 40 msec (irradiation light energy: 0.6 μJ / cm ² ), and the surface potential at 330 msec after the start of irradiation was measured as post-exposure potential VL (V).

[Polydimethylsiloxane immersion test] The photosensitive drum after the initial sensitivity measurement was immersed in polydimethylsiloxane (KF-96 50cs manufactured by Shin-Etsu Chemical) at 23 ° C / 65%.
For 1 hour in the environment described above. After taking out from polydimethylsiloxane and storing in a dark place for 3 hours, sensitivity measurement and
A gray image check was performed. Image confirmation is made by Mita Industries An
This was performed using tico70.

[Fingerprint Adhesion Test] Fingerprints were adhered to the surface of the photoreceptor, stored at 50 ° C. for 10 days, and the state of the surface of the photoreceptor after storage was visually observed.

Table 1 shows the measurement results of the above photoreceptors.
Shown in

[0058]

[Table 1] ──────────────────────────────────── Fingerprint adhesion test Polydimethylsiloxane immersion test ──外 観 外 観 Appearance after storage VL before immersion VL change rate after immersion Gray after immersion Image 感光 Photoconductor A No abnormality 173V 178V 3% No abnormality Photoconductor B No abnormality 170V 213V 25% No abnormality Photoreceptor C Cracking 169V 223V 32% Immersion part white mark generation ─────────────────────────── ─────────

[0059]

According to the present invention, it has been found that the occurrence of cracking due to the adhesion of a fingerprint on an organic photoreceptor can be accurately evaluated by the rate of change in sensitivity before and after immersion in polydimethylsiloxane for one hour. Thus, according to the present invention,
By using an organic photoreceptor having a sensitivity change rate of 25% or less before and after immersion in polydimethylsiloxane for 1 hour, an organic photoreceptor drum which is prevented from being deteriorated due to fingerprint attachment without providing a surface protective layer is supplied. As a result, it has become possible to provide an organic photosensitive drum for an image forming apparatus capable of continuously and stably obtaining a good image without disposing a drum cover or the like.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroshi Mishima 1-28-28 Tamazo, Chuo-ku, Osaka-shi Mita Kogyo Co., Ltd.

Claims (1)

[Claims] 1. A wavelength of 780 nm and an energy of 0.6 μJ / cm ² before and after immersion in polydimethylsiloxane for 1 hour.
An electrophotographic organic photoreceptor, wherein the rate of change of sensitivity to light is 25% or less.