JPS62234164A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an excellent electrophotographic sensitive body which is less changed in surface potential in the stage of preexposing, rising characteristic in the initial period of electrostatic charge and dark attenuation by incorporating an org. phosphite compd. as a photodeterioration preventive agent into an electric charge generating layer or charge transfer layer. CONSTITUTION:The org. phosphite compd. is incorporated as the photo deterioration preventive agent into at least either of the charge generating layer 15 and charge transfer layer 17. The content of the org. phosphite compd. is adequately 0.01-20wt% in the case of adding the same to the charge generat ing layer 15 and is adequately 0.01-5wt% in the case of adding the same to the charge transfer layer 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor containing an organic phosphite compound as a photodegradation inhibitor.

long rice limb five In general, the Carlson electrophotographic process is

The surface of the electrophotographic photoreceptor is charged in the dark, image exposure is performed on top of the electrostatic latent image to form an electrostatic latent image, this is developed with dry or wet toner, and the resulting toner image is transferred to transfer paper such as plain paper. The process consists of transferring and fixing. Photoreceptors used in such processes must have good charging characteristics, high sensitivity, low dark decay, low residual potential after exposure, and changes in the electrostatic characteristics upon repeated use. is required to be small. On the other hand, as an electrophotographic photoreceptor, a charge generation layer mainly composed of an organic charge generation substance such as an azo pigment or a perylene pigment is formed on a conductive support, and polyvinylcarbazole (PVK) is used as an electrophotographic photoreceptor.
Organic types are known that are provided with a charge transport layer containing a charge transport material as a main component consisting of an electron-donating compound such as or an electron-accepting compound such as trinitrofluorenone (TNF).

This type of organic photoreceptor satisfies the above-mentioned requirements for photoreceptors to some extent.

Due to the photomemory effect, when a surface is irradiated with high-intensity light, the surface potential generated in the subsequent f-electrification and exposure process, the rise characteristics of the potential at the initial stage of charging, and the dark decay change significantly compared to before the light irradiation ( (this phenomenon is called pre-exposure fatigue), and as a result, it becomes difficult to obtain high-density and stable images. Furthermore, these defects also occur due to optical fatigue during actual use (running). As described above, conventional organic photoreceptors suffer from significant optical fatigue, making it inconvenient to handle them in a dark place, and furthermore, there is a problem in that electrophotographic characteristics deteriorate with repeated use.

On the other hand, it is thought that the cause of the above defects is due to ultraviolet rays or ozone during exposure or charging, and benzotriazole-based,
Attempts have been made to add benzophenone-based ultraviolet absorbers, phenylenediamine-based ozone deterioration inhibitors, phenolic antioxidants, pentavalent organic phosphorus compound-based photodegradation inhibitors, etc., but results have not yet been satisfactory. has not been obtained.

An object of the present invention is to provide an excellent electrophotographic photoreceptor with very little change in surface potential during pre-exposure, rise characteristics at the initial stage of charging, and dark decay, that is, very little pre-exposure fatigue and optical fatigue during running. That's true.

The electrophotographic photoreceptor of the present invention has a charge generation layer and a charge transport layer provided on a conductive support, wherein the charge generation layer or the charge transport layer contains a photodegradation inhibitor. It is characterized by containing an organic phosphite compound.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an example of the structure of the electrophotographic photoreceptor of the present invention, in which a photosensitive layer 13 is formed on a conductive support 11, and the photosensitive layer 13 includes a charge generation layer 15 and a charge transport layer. 17
are sequentially stacked.

In this configuration example, at least one of the charge generation layer 15 and the charge transport layer 17 contains an organic phosphite compound as a photodegradation inhibitor.

The organic phosphite compound usually has the following general formula (I
) It is positioned as a type of trivalent phosphorus compound.

(Rx, Ry, Rz are hydrogen or substituted or unsubstituted aliphatic or aromatic groups. However, Rx, Ry =
R2 cannot be hydrogen at the same time. ) When one or both of Rx, Ry, and Rz are hydrogen, the following tautomerism is observed.

(Left below) Among these phosphite compounds, RX,
Ry and R2 all have 4 or more carbon atoms (typically 4 to 26
) are preferably aliphatic groups, and more preferably all are aliphatic groups having 8 or more carbon atoms (typically 8 to 26).

Representative examples of phosphite compounds include those represented by the following general formulas (II) to (IV).

(In the formula, R~R1□, A, and n are as follows.

R1 to R □: Each may be the same or different, and may be a substituted or unsubstituted hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted allyl group, or an alkylaryl group. Represents an aryl group of Tomoe exchange. However, R1 to R do not all become hydrogen atoms at the same time, A: [substituted or unsubstituted alkylene group, or substituted or unsubstituted aromatic group, n: an integer of 0 or 1) the above general formula In (n), Ri, R. , R. are all alkyl groups or alkenyl groups having 4 or more carbon atoms (typically 4 to 26), more preferably all are alkyl groups having 8 or more carbon atoms (typically 8 to 26) or alkenyl group. In the case of the above general formula (■), it is preferable that R4 and R are all alkyl groups or alkenyl groups having 4 or more carbon atoms (typically 4 to 26), and more preferably all carbon atoms. It is an alkyl group or alkenyl group of number 8 or more (typically 8 to 26).

In the case of the above general formula (IV), and R6 to R have a total of 4 or more carbon atoms (typically 4 to 26
) are preferably alkyl or alkenyl groups, and more preferably all are alkyl or alkenyl groups having 8 or more carbon atoms (typically 8 to 26).

Specific examples of these phosphite compounds include the following.

Trimethyl phosphite Triethyl phosphite Tri-n-butyl phosphite Trioctyl phosphite Tridecyl phosphite Tridodecyl phosphite Tristearylphosphite Trioleyl phosphite Tristridecyl phosphite Tricetyl phosphite Dilauryl hydride Diene phosphite Diphenyl mono Decyl phosphite diphenyl mono(tridecyl) phosphite tetraphenyl dipropylene glycol phosphite 4,4'-buteridenbis(3-methyl-6-t-phenyl-tridecyl) phosphite distearyl pentaerythritol diphosphite ditridecyl pentaerythritol di Phosphite dinonylphenyl pentaerythritol diphosphite diphenyloctyl phosphite tera(tridecyl)-4,4'-isopropylidene diphenylcyphosphite tris(2,4-di-butylphenyl) phosphite di(,2.4 -di-t-butylphenyl) pentaerythritol diphosphite di(nonylphenyl) pentaerythritol diphosphite (the following is a blank space) (However, Bu represents a butyl group) In any case, as a trivalent organic phosphorus compound, All can be used, for example, Special Publication No. 51-40589,
No. 51-25064, No. 50-35097, No. 49
-20928, 48-22330, 51-35
Those described in No. 193 and the like can also be used.

The above organic phosphite compounds may be used alone or in combination.

When an organic phosphite compound is added to the charge generation layer 15, it is suitably added in an amount of about 0.01 to 20% by weight based on the charge generation substance, although it varies depending on the charge generation substance and the binder. Preferably it is 0.05 to 5% by weight.

Further, when the organic phosphite compound is added to the charge transport layer 17, it is appropriate to add it in an amount of 0.01 to 5% by weight based on the charge transport material, although it varies depending on the charge transport material and binder. Preferably it is 0.04 to 2.4% by weight.

The charge generation layer 15 includes a charge generation substance and a binder,
Furthermore, the organic phosphite compound described above can be included.

As a charge generating substance, C.I. Pigment Blue 25
(Color Index (CI) 21180), C.I. Pigment Red 41 (CI 21200), C.I. Acid Red 52 (CI 45100), C.I. Acid Red 52 (CI 45100), C.I. 95033), azo pigments having a styrylstilbene skeleton (described in JP-A-53-133229), azo pigments having a triphenylamine skeleton (described in JP-A-53-132)
547), azo pigments having a dibenzothiophene skeleton (described in JP-A-54-217287)
, an azo pigment having an oxadiazole skeleton (Japanese Unexamined Patent Application Publication No. 54
-127427), an azo pigment having a fluorenone skeleton (described in JP-A-54-22837)
, an azo pigment having a bisstilbene skeleton (Japanese Unexamined Patent Publication No. 1983-
17733), an azo pigment having a distyryloxadiazole skeleton (described in JP-A-54-2129), an azo pigment having a distyrylcarbazole skeleton (described in JP-A-54-17734) , an azo pigment having a carbazole skeleton (JP 57-195767
, described in JP-A-57-195767), CI Pigment Blue 16 (CI 74100),
Phthalocyanine pigments such as C.I. Butt Brown 5 (CI73410), C.I. Butt Dye (CI
Indigo pigments such as 73030) and perylene pigments such as Argo Scarlet B (manufactured by Bayer) are used alone or in combination.

Among these charge generating substances, disazo pigments having a fluorenone skeleton represented by the following general formula (A) and trisazo pigments having a triphenylamine skeleton represented by the following general formula (B) are preferred.

(wherein A1 is X', A r", A r", R1
, R'' are as follows.

Xl: aromatic rings such as benzene rings and naphthalene rings, or hetero rings such as indole rings, carbazole rings, and benzofuran rings, or substituted products thereof; Ar": aromatic rings such as benzene rings and naphthalene rings;
or a hetero ring such as a dibenzofuran ring or a substituted product thereof; Ar2: an aromatic ring such as a benzene ring or a naphthalene ring or a substituted product thereof; R1: hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof.

R2: alkyl group, carbamoyl group, carboxyl group or ester thereof) In the formula, -A2 is, where X'', Ar', Ar', A
r'.

R3, R', and R' are as follows.

X2: An aromatic ring such as a benzene ring or a naphthalene ring, or a hetero ring such as an indole ring, a carbazole ring, or a benzofuran ring.

or a substitute thereof, Ar3. Ar': aromatic ring such as a benzene ring or naphthalene ring, or a hetero ring such as a dibenzofuran ring, or a substituted product thereof; Ar': an aromatic ring such as a benzene ring or naphthalene ring or a substituted product thereof; R3, R ', hydrogen, lower alkyl group or phenyl group or a substituent thereof, R4 = alkyl group, carbamoyl group, carboxyl group or ester thereof) The substituents for Xl in general formula (A) and X2 in general formula (B) are: Examples include halogen atoms such as chlorine atoms and bromine atoms, alkoxy groups, and alkyl groups.

Ar' in general formula (A) and Ar3 in general formula (B). Substituents for Ar' include alkyl groups such as methyl, ethyl, propyl, and butyl; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; halogen atoms such as chlorine and bromine; Dialkylamino groups such as dimethylamino groups and diethylamino groups, dialkylamino groups such as dibenzylamino groups, halomethyl groups such as trifluoromethyl groups, nitro groups, cyano groups, carboxyl groups or their esters, hydroxyl groups, -8o, Na Examples include the sulfonic acid group of Nato.

In addition, Ar'' in general formula (A) and general formula (B)
Substituents for Ar' include alkyl groups such as methyl, ethyl, propyl, and butyl; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; nitro, chlorine, and bromine; Examples include halogen atoms, dialkylamino groups such as dimethylamino group, and diethylamino group.

Furthermore, R1 in general formula (A) and R3 in general formula (B). Examples of substituents for the phenyl group of R5 include halogen atoms such as chlorine atoms and bromine atoms.

For specific compounds of general formula (A), please refer to JP-A-53
It is described in detail in JP-A-132547.

For specific compounds of general formula (B), please refer to JP-A-54
It is described in detail in JP-A-22834.

As the binder used in the charge generation layer, polyvinyl butyral resin, polyvinyl formal resin, polyester resin, polycarbonate resin, polystyrene, polyvinyl acetate, polyamide, polyurethane, various celluloses, etc. are used.

The charge generating layer can be provided on a support by dispersing a charge generating substance in a solvent together with a binder if necessary, and by coating, dipping or the like. The binder is a charge generating substance 100
It is appropriate to use about 5 to 150 parts by weight per part by weight.

In addition, when no photodegradation inhibitor is added to the charge generation layer 15, inorganic photosensitive materials such as Sa, Se alloy, and a-Si can be used, and these can be supported by methods such as vapor deposition, sputtering, and glow discharge. Formed on the body.

The thickness of the charge generation layer is 0.05 to 20μ, preferably 0.05μ to 20μ.
Approximately 1 to 2 μm is appropriate.

The charge transport layer 17 contains a charge transport substance and a binder.

The charge transport substance may be an electron-donating compound or an electron-accepting compound, and among them, an α-substituted stilbene compound represented by the following general formula CC") and a hydrazone compound represented by the general formula (D) below, which are electron-donating compounds. is preferred.

(In the formula, R6 represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, R7, R8 and R9 represent a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, Ar' represents a substituted or unsubstituted aryl group, and Ar7 represents a substituted or unsubstituted arylene group. Ar' and R6 may jointly form a ring. is an integer of O or 1.) The above general formula (C) R'', R', R'Oyobi RJ,
Examples of the alkyl group in - include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, etc. Substituents in the substituted alkyl group include methoxy group, ethoxy group, propoxy group, butoxy group, pentyl group, etc. Alkoxy groups such as oxy groups, aryloxy groups such as phenoxy groups, tolyloxy groups, naphthyloxy groups,
Aryl groups such as phenyl group and naphthyl group, dimethylamino group, diethylamino group, dipropylamino group, N-
alkylamino groups such as methyl-N-dithylamino groups,
Examples include arylamino groups such as N-phenylamino group and N,N-diphenylamino group, hydroxy group, and amino group. There may be one or more substituents on the alkyl group, <', and if there are two or more substituents, they may be the same group or different groups. Specific examples of substituted alkyl groups include alkoxyalkyl groups, aryloxyalkyl groups, and aminoalkyl groups.

Examples include hydroxyalkyl group, aralkyl group, alkylaminoalkyl group, and arylaminoalkyl group.

Furthermore, the aryl group in Ar', R6, R7, R1 and R9 is a carbocyclic or heterocyclic mononuclear or polynuclear aromatic ring residue, more specifically a phenyl group, a naphthyl group, an anthryl group. , chenyl group, pyridyl group, furyl group, cambazolyl group, or styryl group, etc. Substituents in substituted aryl groups include alkylamino groups such as dimethylamino group, diethylamino group, and dipropylamino group, dipropylamino group, etc. alkoxy groups such as a fulkylamino group, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a phenoxy group, and a tolyloxy group.

Aryloxy groups such as naphthyloxy groups, alkyl groups such as diphenylamino groups, methyl groups, ethyl groups, propyl groups, butyl groups, amino groups such as ditolylamino groups,
Examples include halogen atoms such as a hydroxy group, phenyl group, chlorine atom, and bromine atom, alkylthio groups such as cyano group, nitro group, and ethylthio group, and arylthio groups such as phenylthio group and naphthylthio group.

There may be one or more substituents on the aryl group,
When there are two or more groups, they may be the same group or different groups. Specific examples of the substituted aryl group include dialkylaminoaryl group, alkoxyaryl group, aryloxyaryl group, alkylaryl group, diarylaminoaryl group, aminoaryl group, hydroxyaryl group,
Examples include a phenylaryl group, a haloaryl group, a cyanoaryl group, a nidroaryl group, a thioalkoxyaryl group, and a thioaryloxyaryl group.

Examples of the arylene group of Ar' include the above-mentioned carbocyclic or heterocyclic mononuclear or polynuclear aromatic residues,
Further, examples of the substituent in the substituted arylene group include the substituents in the above-mentioned substituted aryl group. The arylene group may have one or more substituents, and 2
If there are more than two, they may be the same or different groups.

Examples of those in which Ar' and R' together form a ring include furorenyl, cyclopentagenyl, cyclohexagenyl, cyclohexenyl, and cyclopentenyl. These rings may have the above-mentioned substituents.

Note that specific examples of the α-substituted styryl compound are as follows.

Other specific examples are described in detail in JP-A-60-98437.

A hydrazone compound represented by the following general formula (D') is also preferable as a charge transport substance, and can exhibit remarkable effects when used in combination with the photodegradation inhibitor of the present invention.

[In the formula, Rlo is a methyl group, an ethyl group, a propyl group, 2
-hydroxyethyl group, 2-chloroethyl/L4, or
represents a substituted or unsubstituted alkyl group such as a benzyl group, or a substituted or unsubstituted phenyl group, R11 represents a methyl group, ethyl group, benzyl group, or a substituted or unsubstituted phenyl group, R'' is hydrogen, Chlorine, bromine, carbon number 1
-4 alkyl group, a flucoxyl group having 1 to 4 carbon atoms, a dialkylamino group, or a nitro group. ] Specific examples of hydrazone compounds include the following, and other specific examples can be found in JP-A-55-46760.
The details are described in the publication.

(Left below) Other electron-donating compounds include compounds containing at least one of an alkyl group such as a methyl group, an alkoxy group, an amino group, an imino group, and an imido group, or anthracene in the main chain or side chain.

There are compounds with polycyclic aromatic residues such as pyrene, phenanthrene, and coronene, or nitrogen-containing ring residues such as indole, carbazole, oxazole, isoxazole, thiazole, imidazole, pyrazole, oxadiazole, thiadiazole, and triazole. Examples of low molecular weight substances include hexamethylene diamine, N-
(4-aminobutyl)cadaverine, aS-didodecylhydrazine, p-toluidine, 4-amino-〇-xylene, N,N'-diphenyl-1,2-diaminoethane, o
-, m- or p-ditolylamine, triphenylamine, diphenylmethane, triphenylmethane, durene, 2-bromo-3,7-dimethylnaphthalene, 2,3°5-trimethylnaphthalene, N'-(3-bromphenyl )-N-(β-naphthyl)urea, N-methyl-N-(
α-naphthyl)urea, N,N'-diethyl-N-(α-
naphthyl) urea, 2,6-dimethylanthracene, anthracene, 2-phenylanthracene, 9,10-diphenylanthracene, 9,9'-bianthranil, 2-
Dimethylaminoanthracene, phenanthrene, 9-aminophenanthrene, 3,6-dimethylphenanthrene, 5,7-dipromo-2-phenylindole, 2,3
-dimethylindoline, 3-indolylmethylamine,
Carbazole, 2-methylcarbazole, N-ethylcarbazole, 9-phenylcarbazole, 1,1-dicarbazole, 3-(p-methoxyphenyl)oxazolidine, 3,4.5-trimethylisoxazole, 2-
Anilino-4,5-diphenylthiazole, 2,4.5
-trinitrophenylimidazole, 4-amino-3,
5-dimethyl-1-phenylpyrazole, 2,5-diphenyl-1,3,4-oxadiazole, 1,3゜5-
Triphenyl-1,2,4-triazole, 1-amino-5-phenyltetrazole, bis-diethylaminophenyl-1,3,6-oxadiazole, etc., and poly-N-vinylcarbazole as a high molecular weight one. and its derivatives (for example, carbazole bones having halogens such as chlorine and bromine, and substituents such as methyl groups and amino groups), polyvinylpyrene, polyvinylandranthene, pyrene-formaldehyde condensation polymers and their derivatives (for example, pyrene bones) Examples include those having a halogen such as bromine or a substituent such as a nitro group in the nucleus.

On the other hand, electron-accepting compounds include carboxylic acid anhydrides, compounds with electron-accepting core structures such as ortho- or para-quinoid structures, and alicyclic compounds having electron-accepting substituents such as nitro and cyano groups. compounds, aromatic compounds, heterocyclic compounds, and more specifically maleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, naphthalic anhydride, pyromellitic anhydride, chlor-p- Benzoquinone, 2,5-dichlorobenzoquinone, 2,6-dichlorobenzoquinone, 5,8
-dichlornaphthoquinone, 0-chloranyl 50-bromoanyl, P-chloranyl, P-bromoanyl, P-
Iodoanil, tetracyanoquinodimethane, 5,6-chiraledione, coumarin-2,2-dione, oxindirubin, oxyindigo, 1,2-dinitroethane,
2,2-dinitropropane, 2-nitro-nitrosopropane, iminodiacetonitrile, succinonitrile, tetracyanoethylene, 1,1,3,3-tetracyanopropenide, o-, m- or P-dinitrobenzene.

1.2.3-trinitrobenzene, 1,2.4-dolinitrobenzene, 1,3.5-trinitrobenzene, dinitrodibenzene, 2,4-dinitroacetophenone, 2
, 4-dinitrotoluene, 1,3.5-trinitrobenzophenone.

1.2.3-trinitroanisole, α,-β-dinitronaphthalene, 1,4,5.8-tetranitronaphthalene, 3,4.5-trinitro-1,2-dimethylbenzene, 3-nitroso-2 -nitrotoluene, 2-nitrone-3,5-dinitrotoluene, o-, m- or p-nitronitron benzene, phthalonitrile, terephthalonitrile, isophthalonitrile, benzoyl cyanide, bromobenzyl cyanide, quinoline cyanide, Cyanide -〇-
Xylylene, o-, m- or p-nitrobenzyl cyanide, 3,5-dinitropyridine, 3-nitro-2-pyridine, 3°4-dicyanopyridine, α-9β- or γ-
Cyanopyridine, 4,6-sinitroquinone, 4-nitroxanthone, 9,10-dinitroanthracene, 1-nitroanthracene, 2-nitrophenanthrenequinone,
2,5-dinitrofluorenone, 2,6-dinitrofluorenone, 3゜6-dinitrofluorenone, 2,7-dinitrofluorenone, 2,4.7-dolinitofluorenone, 2,4,5.7-tetranitrofluorenone, 3,
Examples include 6-sinitrofluorenone mandenonitrile, 3-nitrofluorenone mandenonitrile, and tetracyanopyrene.

Binders used in the charge transport layer include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, and polyester.

Polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride.

Polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate, ethyl cellulose, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin.

Examples include thermoplastic resins such as phenol resins and alkyd resins, thermosetting resins, and the like. The amount used is 10:1 to 1:10, preferably 1:2 to 2: by weight with the charge transport material.
The range is 1.

In addition, known plasticizers, leveling agents, etc. can be added to the charge transport layer. Charge transport thickness is 2-200
μ, preferably 5 to 30 μ.

The conductive support may be a plastic film or cylinder on which aluminum, nickel, chromium, tin oxide, insidium oxide, or the like is deposited (plastics include polyester, polypropylene, cellulose acetate, etc.).

); Paper or plastic film laminated with a conductive thin film such as aluminum foil, plate or cylinder made of metal such as aluminum, nickel, stainless steel, iron, etc. FIG. 2 shows the electrophotographic photoreceptor of the present invention. 2 is a sectional view showing another example of the structure, in which an undercoat layer 19, a charge generation layer 15, and a charge transport layer 17 are sequentially laminated on a conductive support 11. FIG.

Phosphite compound (photodegradation inhibitor).

Subbing layer 19. Charge generation layer 15 or charge transport layer 17
It is added to at least one layer of.

The amount of organic phosphate ester added to the charge generation layer 15 and the charge transport layer 17 and the composition of each layer are as follows.

The undercoat layer 19 is provided for the purpose of improving chargeability, improving adhesive properties, and preventing moiré, and is made of polyamide, polyvinyl acetate, polyurethane, alcohol-soluble nylon, polyvinyl butyral, water-soluble polyvinyl butyral, etc. The main component is resin, and aluminum oxide, tin oxide, conductive carbon, zinc oxide, etc. can also be dispersed therein.

The thickness of the undercoat layer 17 is suitably about 0.01 to 10 microns, preferably about 0.01 to 5 microns.

11B needle (Shuichi) According to the present invention, by incorporating an organic phosphite as a photodegradation inhibitor into the charge generation layer or the charge transport layer, the surface potential during pre-exposure, the initial charge rise characteristics, and the dark Variations in attenuation, that is, deterioration of characteristics due to optical fatigue, are prevented, and a high-quality electrophotographic photoreceptor can be realized. Particularly useful for the body.

The present invention will be explained below with reference to Examples.

Note that both parts and percentages are based on weight.

Example 1 1.7 parts of a disazo pigment represented by the following structural formula, 13.6 parts of a 5% tetrahydrofuran solution of polyvinylbratyl (XYHL manufactured by Union Carbide Plastics) and 44.2 parts of tetrahydrofuran were dispersed in a ball mill for 48 hours. Then, 22.3 g of Tetrahyto Lofuran and 37.2 g of ethyl cellosolve were added and dispersed for 1 hour. The obtained mill base was diluted with tetrahydrofuran so that the weight ratio of tetrahydrofuran: ethyl cellosolve was 426 and the solid content concentration was 1%, and this was applied with a doctor blade onto a polyester film on which aluminum had been deposited. It was dried at 80° C. for 5 minutes to form a charge generation layer with a thickness of about 0.8 μm.

Next, apply 20 parts of polycarbonate (1300 to Panlite manufactured by Konjin Kasei Co., Ltd.) and silicone oil on this charge generation layer.
A charge transport layer forming liquid consisting of 0.004 parts (KF50 manufactured by Shin-Etsu Chemical Co., Ltd.), trioleyl phosphite 0.038 parts (Tokyo Kasei Co., Ltd. 11P-390) and 152 parts of methylene chloride was applied with a doctor blade and heated at 80°C for 2 minutes. Then, it was dried at 130° C. for 5 minutes to form a charge transport layer with a thickness of about 19 μm.

Comparative Example 1 An electrophotographic photoreceptor was prepared in the same manner as in Example 1 except that trioleylphosphite was removed from the charge transport layer forming liquid.

Example 2 2.5 parts of triazo pigment represented by the following structural formula, 5% of polyvinyl formal (Denka formal #20 manufactured by Denki Kagaku Kogyo Co., Ltd.)
10 parts of cyclohexanone solution and 4 parts of cyclohexanone
After 7.5 parts were dispersed in a ball mill for 48 hours, 90 parts of cyclohexanone was further added and dispersed for 1 hour. The resulting mill base.

Diluted with cyclohexanone to a solid concentration of 1%, applied with a doctor blade onto a polyester film coated with aluminum, and heated at 80°C for 5 minutes.
It was dried for a minute to form a charge generation layer with a thickness of about 0.4 μm.

Next, instead of trioleyl phosphite, tristearyl phosphite (Johoku Kagaku Kogyo Co., Ltd. 111JP-3t8)
Prepare the same charge transport layer forming solution as in Example 1 except for using E) and a compound having the following structure as the α-stilbene compound, and apply it on the charge generation layer in the same manner as in Example 1. An electrophotographic photoreceptor was formed by coating to form a charge transport layer.

An electrophotographic photoreceptor was formed in the same manner as in Example 2 except that tristearylphosphite was removed from the charge transport layer forming liquid.

The four types of electrophotographic photoreceptors created as described above were placed in an electrostatic copying paper test bag! (manufactured by Kawaguchi Electric Seisakusho Co., Ltd., Model 5P428), and the electrophotographic characteristics were evaluated under the following conditions (measured in dynamic mode).

First, -6KV corona discharge was performed for 20 seconds to charge the surface, and the surface potential V□(V) after 1 second and 20 seconds of charging.

It), V3 (Volt) was measured, left in a dark place for another 20 seconds, the surface potential Vo (Volt) at that time was measured, and the Vo/Vs ratio was determined as the dark decay ratio.
, exposure amount E□ required for Vo to attenuate to 1710 as sensitivity by irradiating white tungsten light of 51ux
7□. (lux, 5ec) was measured and set as initial characteristics.

In addition, each photoreceptor was irradiated with light for 30 minutes using a 10001ux daylight fluorescent lamp, and then left in a dark place for 30 seconds.
The same measurements as the initial characteristics were performed to determine the characteristics after photo-fatigue.

The above results are shown in Table-1. In the table, the amount of change is (potential after photo-fatigue)/(initial potential).

(Left below) Example 3 An electrophotographic photoreceptor was prepared in the same manner as in Example 1, except that the trioleyl phosphite in the charge transport layer forming solution was replaced with an organic phosphite compound shown in Table 2 below. Created. The initial characteristics and optical fatigue characteristics of these photoreceptors are also listed in the same table.

(The following is a blank space) Comparative Examples 3 to 8 Electrophotographic photoreceptors were prepared in the same manner as in Example 1, except that the trioleyl phosphite in the charge transport layer forming liquid was replaced with the compound shown in Table 3 below.

The initial characteristics and optical fatigue characteristics of these photoreceptors are also listed in the same table.

(Margin below) Example 12 A charge generation layer was formed in the same manner as in Example 1'.

Next, apply 20 parts of polycarbonate (1300 to Panlite manufactured by Konjin Kasei Co., Ltd.) and silicone oil on this charge generation layer.
0.004 part (KF50 manufactured by Shin-Etsu Chemical Co., Ltd.) Tristearylphosphite 0.038 part (JP-318E manufactured by Johoku Chemical Co., Ltd.) Tetrahydrofuran
A charge transport layer forming liquid consisting of 152 parts was applied with a doctor blade, heated at 80°C for 2 minutes, and then heated at 120°C.
An electrophotographic photoreceptor was prepared by drying at .degree. C. for 5 minutes to form a charge transport layer with a thickness of about 19 .mu.m.

Comparative Example 9 An electrophotographic photoreceptor was prepared in the same manner as in Example 12 except that tristearylphosphite was removed from the charge transport layer forming liquid.

Example 13 A charge generation layer was formed in the same manner as in Example 2.

Next, 20 parts of polyacrylate (Niepilon U-1060 manufactured by Unitika) and silicone oil were applied on this charge generation layer.
A charge transport layer forming liquid consisting of 0.006 parts (same as Example 12), trioleylphosphite 0.038 parts (P-390 manufactured by Tokyo Chemical Industry Co., Ltd.) and 152 parts of tetrahydrofuran was applied and dried in the same manner as in Example 12. An electrophotographic photoreceptor was prepared by forming a charge transport layer with a thickness of about 20 μm.

Comparative Example 1O An electrophotographic photoreceptor was prepared in the same manner as in Example 13 except that trioleylphosphite was removed from the charge transport layer forming liquid.

Examples 12 and 13. The characteristics of the photoreceptors of Comparative Examples 9 and 10 were evaluated in the same manner as described above, and the results are shown in Table 4.

(Left below) Examples 14 to 18 An electrophotographic photoreceptor was prepared in the same manner as in Example 12, except that tristearylphosphite in the charge transport layer forming solution was replaced with an organic phosphate compound shown in Table 5 below. Created.

The initial characteristics and optical fatigue characteristics of these photoreceptors are also listed in the same table.

(Left below) Example 19 13.6 parts of a 5% cyclohexanone solution of polyvinyl butyral resin (manufactured by XYHL j UCC) and 44.2 parts of cyclohexanone were dispersed in a ball mill for 48 hours. After dispersion, take out the mill base into a container, 11.
A solution of 0.11 parts of tristearylphosphite dissolved in 9 parts of cyclohexanone was added to prepare a 1% charge generation layer forming solution.

This liquid was applied with a doctor blade onto a polyester film on which aluminum had been vapor-deposited, and dried at 95° C. for 5 minutes to form a charge generation layer with a thickness of 0.5 μI.

Next, apply 20 parts of polycarbonate (Panlite K 1300 manufactured by Konjin Kasei Co., Ltd.) and silicone oil on this charge generation layer.
A charge transport layer forming liquid consisting of 0.004 parts (KF50 manufactured by Shin-Etsu Chemical Co., Ltd.) consisting of 152 parts of tetrahydrofuran was applied with a doctor blade, and dried at 80°C for 2 minutes and then at 130°C for 5 minutes to form a charge transport layer with a thickness of about 19 μm. An electrophotographic photoreceptor was created by forming layers.

Comparative Example 11 An electrophotographic photoreceptor was prepared in the same manner as in Example 19 except that tristearylphosphite was removed from the charge generation layer forming liquid.

Example 20 10 parts of 5% cyclohexanone solution of polyvinyl butyral resin (manufactured by XYHL S UCC) 47.5 parts of cyclohexanone was mixed with 48 parts by ball mill.
After being dispersed for a period of time, 90 parts of cyclohexanone and 0.12 parts of trioleylphosphite were further added, and the mixture was dispersed for 2 hours. The obtained mill base was diluted by adding cyclohexanone so that the solid content concentration was 1%. This is 0.3
Dip coating on μI thick AQ board (#1050), 110
It was dried for 10 minutes at ℃ to form a charge generation layer with a thickness of about 0.4 μm.

(Margin below) Next on this charge generation.

Polycarbonate resin 20 parts (Panlite K 1300 manufactured by Konjin Kasei Co., Ltd.) Silicone oil
A charge transport layer solution consisting of 0.004 parts (KF50, manufactured by Shin-Etsu Chemical Co., Ltd.) and 173 parts of methylene chloride was applied by dip coating and dried to form a charge transport layer of about 20 μm to prepare an electrophotographic photoreceptor.

Comparative Example 12 An electrophotographic photoreceptor was prepared in the same manner as in Example 20, except that trioleylphosphite was removed from the charge generation layer forming liquid in Example 20.

The characteristics of the photoreceptors of Example 19.20 and Comparative Example 11.12 were evaluated in the same manner as above, and the results are shown in Table 6.
It was shown to.

[Brief explanation of drawings]

FIGS. 1 and 2 are cross-sectional views showing an example of the structure of the electrophotographic photoreceptor of the present invention. 11. Conductive support 13. Photosensitive layer 15. Charge generation layer 17. Charge transport layer 19. Undercoat layer procedural amendment September 2, 1988 Commissioner of the Japan Patent Office Black 1) Mr. Yu Akira 2 , Name of the invention Electrophotographic photoreceptor 3, Relationship with the case of the person making the amendment Patent applicant 1-3-6-5 Nakamagome, Ota-ku, Tokyo, ``Detailed description of the invention'' column of the specification to be amended 6. Contents of the amendment (1) On page 5, line 10 of the specification, “○H RX-P=○ H” is corrected to “?H.” (2) On page 31, line 3 of the same specification, “Adhesive ``Improvement of agents''
Corrected to "Improved adhesion."that's all

Claims (1)

[Claims] 1. In an electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are laminated on a conductive support, the charge generation layer or the charge transport layer contains an organic phosphite compound as a photodegradation inhibitor. An electrophotographic photoreceptor featuring: