JP3303201B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to a single-layer organic electrophotographic photosensitive member useful for an electrophotographic copying machine, a printer, and the like.

[0002]

2. Description of the Related Art Conventionally, as a photoconductive material used for an electrophotographic photoreceptor, inorganic photoconductive materials such as selenium, zinc oxide and cadmium sulfide, organic photoconductive materials such as azo pigments, and amorphous silicon are generally used. Are known. However, inorganic photoconductive materials have problems such as photosensitivity, thermal stability, durability, and toxicity. For example, selenium has a drawback that it is easily crystallized by heat, dirt, and the like, and its characteristics are easily degraded. Compared to the electrophotographic photoreceptor using this inorganic photoconductive material, the organic photoconductive material has advantages such as excellent film formability, easy production, high degree of freedom of design, lower cost and no pollution. Therefore, in recent years, electrophotographic photosensitive members using organic photoconductive materials have been actively developed. Electrophotographic photoreceptors using an organic photoconductive material include a function-separated type photoreceptor in which a charge generation layer and a charge transport layer are laminated, and a single-layer type photoreceptor in which a charge generation material is dispersed in a resin binder. Among them, a laminated photoreceptor has been put to practical use because of its higher sensitivity.

For example, Japanese Patent Publication No. 55-42380 discloses a laminated photoreceptor in which chlordiane blue and a hydrazone compound are combined, and a charge generating substance used in the laminated photoreceptor is disclosed in JP-A-53-133445. ,
JP-A-54-21728, JP-A-54-22283
No. 4 and the like, and examples of charge transport materials include JP-A-58-198043 and JP-A-58-19935.
No. 2, for example. However, in the case of a laminated photoreceptor, it is generally necessary to reduce the thickness of the charge generation layer to 0.1 to 1.0 μm in order to increase the sensitivity, and the state of the surface of the conductive substrate and the time of coating It is easily affected by atmosphere and environment, and greatly affects yield, manufacturing cost, and the like.

The charge transport material contained in the charge transport layer is required to have a high charge mobility in order to increase the sensitivity. Most of the charge transport materials having a high charge mobility have a hole transporting property. Therefore, the photoconductors put into practical use are limited to those of negative charge type. Most of such negatively charged photoreceptors utilize a negative corona discharge during use, so that a large amount of ozone is generated, which is not only harmful to the human body but also reacts with the photoreceptor. The life of the photoconductor itself is also shortened. To prevent this, special systems have been proposed and put into practical use, such as a charging system that does not easily generate ozone, a system that decomposes generated ozone, and a system that exhausts ozone in the device. There are disadvantages such as doing.

On the other hand, a single-layer type photoreceptor is generally known as a positively charged type photoreceptor.
No. 0496, polyvinyl carbazole and 2,
A photoreceptor containing 4,7-trinitro-9-fluorenone, a photoreceptor sensitized with polyvinyl carbazole described in JP-B-48-25658 with a pyrylium salt dye, or a photoreceptor containing a eutectic complex as a main component JP-A-47-3
No. 0330, a photoreceptor comprising a charge generating substance and a charge transporting substance, from a perylene pigment and a charge transporting substance described in JP-A-63-271461, JP-A-1-118143, and JP-A-3-65761. And a photoreceptor comprising a phthalocyanine compound and a binder resin described in JP-A-3-65961 have been proposed. However, these single-layer type photoreceptors are inadequate particularly in terms of sensitivity, and are inferior to the lamination type photoreceptors.

[0006] In recent years, with the increasing complexity and function of copiers, photoconductors corresponding to copiers having analog and digital functions have been developed. In this case, the characteristics required for the photoconductor are
It is desirable to have high sensitivity in the wavelength of the LD laser light source, that is, in the near-infrared region, and to have high sensitivity in the wavelength of the white light source, that is, in the visible region to support the analog function.

As such a photoreceptor, Japanese Patent Application Laid-Open No.
236047, JP-A-63-243950, JP-A-63-243951, JP-A-1-31
No. 5752 discloses a laminated photoreceptor having a mixture of a pigment having sensitivity in the visible region and a pigment having sensitivity in the near infrared region and having a wide spectral sensitivity from the visible region to the near infrared region. However, in the case of these stacked types, since the charge transporting substance coming in the upper layer absorbs light, there is a disadvantage that the light sensitivity is deteriorated particularly in a short wavelength range, and the range is from the visible range to the near infrared range. It was not always enough to have a wide spectral sensitivity.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a single layer which is inexpensive, has high sensitivity particularly in the visible range to the near infrared range, and has excellent charging characteristics. It is an object of the present invention to provide an electrophotographic photosensitive member of a mold type.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a mixture obtained by simultaneously pulverizing and mixing a disazo pigment and a trisazo pigment on a conductive support, a charge transport material, and a binder. The present inventors have found that an electrophotographic photoreceptor provided with a single photoconductive layer containing a resin and an antioxidant is suitable for the above object, and have completed the present invention.

That is, according to the present invention, in a photoconductor for electrophotography comprising a photoconductive layer formed on a conductive support, the photoconductive layer comprises at least one specific disazo pigment and at least one type of disazo pigment. Comprising a single layer containing a co-ground mixture of the above trisazo pigment, a charge transport material, a binder resin, and an antioxidant.

The photoreceptor for electrophotography according to the present invention comprises, in a single photoconductive layer, a disazo pigment having sensitivity to visible light and a trisazo pigment having sensitivity to so-called near-infrared light having a wavelength of 700 nm or more. And high sensitivity to a wide range of light from visible light to near-infrared light. Although this sensitizing effect will be clarified in the examples described below, by mixing and grinding the disazo pigment and the trisazo pigment simultaneously by applying mechanical energy, the sensitivity is significantly sensitized more than the case of each pigment alone. This is different from the mixing effect of a conventionally proposed combination of pigments.

The optimum mixing ratio of the disazo pigment and the trisazo pigment used in the present invention is determined in consideration of the characteristics (sensitivity, charging characteristics, gas resistance) required of the photoreceptor depending on the type of the pigment to be mixed. Can be selected individually,
Generally, the weight ratio is preferably in the range of 0.01 ≦ disazo pigment / (disazo pigment + trisazo pigment) ≦ 0.99. If it is lower than 0.01, the sensitivity sensitizing effect is small,
If it is larger than 0.99, the sensitizing effect and the improvement in gas resistance are reduced. Further, considering the uniformity of spectral sensitivity from the visible light wavelength region to the near infrared light wavelength region, the range of 0.1 ≦ disazo pigment / (disazo pigment + trisazo pigment) ≦ 0.9 is desirable.

The disazo pigment and the trisazo pigment may be mixed by a method such as ball mill, vibration mill, disk vibration mill, attritor, sand mill, paint shaker, jet mill, ultrasonic dispersion method, etc. Any pulverizing / mixing means for providing mechanical energy such as friction, stretching, impact, and vibration can be used. Further, it is preferable that desired amounts of the disazo pigment and the trisazo pigment are contained in the same container, and the above-mentioned mechanical energy is simultaneously applied and mixed and pulverized in the presence of a dispersion solvent to be described later to perform dispersion.

In the electrophotographic photoreceptor of the present invention, as described above, a mixture of a disazo pigment and a trisazo pigment is used as the charge generating material, and in particular, light irradiation in the visible light region (400 to 700 nm). A disazo pigment represented by the following general formula 1 having a high charge generation capability by the following general formula 2 which is particularly sensitive to light having a wavelength of 700 nm or more.
A co-ground mixture with a trisazo pigment represented by

[0015]

Embedded image

Embedded image

Wherein A, B and D in the above formulas 1 and 2 represent a coupler residue represented by the following formula 3
R ₁ represents a hydrogen atom, a chlorine atom, a fluorine atom, an iodine atom, a bromine atom, —NO ₂ or —CN.

[0017]

Embedded image ｛Wherein, X represents a naphthalene ring, an anthracene ring, a carbazole ring, a benzocarbazole ring, a polycyclic aromatic ring selected from a dibenzofuran ring and a dibenzothiophene ring, or a heterocyclic ring bonded to a benzene ring. And R ₂ and R ₃ represent a group selected from a hydrogen atom, a substituted or unsubstituted alkyl group, an aryl group and a heterocyclic group, and R ₂ and R ₃ represent a ring together with a nitrogen atom to be bonded. May be formed. R ₄ and R ₅ each represent a group selected from a substituted or unsubstituted alkyl group and an aryl group;
Represents a divalent group of an aromatic hydrocarbon or a divalent group of a heterocyclic ring containing a nitrogen atom in the ring, and R ₆ , R ₇ , R ₈ and R ₉ represent a hydrogen atom, a substituted or unsubstituted alkyl group, an aralkyl Group, represents a group selected from an aryl group and a heterocyclic group,
R ₈ and R ₉ may form a 5- or 6-membered ring. In this case, the 5- or 6-membered ring may have a condensed aromatic ring. Z is a naphthalene ring, an anthracene ring, a carbazole ring, a benzocarbazole ring formed by condensing with a benzene ring,
It indicates a residue necessary for forming a polycyclic aromatic ring or hetero ring selected from a dibenzofuran ring, a benzonaphthofuran ring and a dibenzothiophene ring. Ar ¹ and Ar ² are
An aromatic ring such as a benzene ring or a naphthalene ring or a substituted product thereof, and R ₁₀ and R _{11 each} represent a hydrogen atom, a lower alkyl group, a carboxyl group or an ester thereof. ｝)

Next, specific examples of couplers of the above-mentioned disazo pigments and trisazo pigments used in the electrophotographic photoreceptor of the present invention, that is, specific examples of AH, BH and DH are shown in Table 1 below. To Table 16 below.

[0019]

[Table 1- (1)]

[0020]

[Table 1- (2)]

[0021]

[Table 1- (3)]

[0022]

[Table 2- (1)]

[0023]

[Table 2- (2)]

[0024]

[Table 3- (1)]

[0025]

[Table 3- (2)]

[0026]

[Table 4]

[0027]

[Table 5]

[0028]

[Table 6]

[0029]

[Table 7]

[0030]

[Table 8]

[0031]

[Table 9]

[0032]

[Table 10]

[0033]

[Table 11]

[0034]

[Table 12- (1)]

[0035]

[Table 12- (2)]

[0036]

[Table 12- (3)]

[0037]

[Table 13- (1)]

[0038]

[Table 13- (2)]

[0039]

[Table 13- (3)]

[0040]

[Table 14- (1)]

[0041]

[Table 14- (2)]

[0042]

[Table 15]

[0043]

[Table 16]

Among the azo pigments described above, among the disazo pigments, compounds represented by the following formulas (19) and (20) are particularly preferable. These compounds have high sensitivity in the visible region, and when simultaneously pulverized and mixed in combination with a trisazo pigment, the stability of the pigment dispersion coating solution is good, a good coating film can be formed, and a large sensitization is achieved. The effect can be expected.

[0045]

Embedded image

Embedded image

As the trisazo pigment, a compound represented by the following general formula (21) is preferable.
And Formula 23 are preferred. This is because the trisazo compound represented by the general formula (21) is particularly useful in the near infrared region (700 n
m or more) is a material having a high charge generation ability by light irradiation,
Simultaneous pulverization and mixing with a disazo pigment makes it possible to prepare a photoreceptor having high photosensitivity over a wide range from the visible region to the near-infrared region. Particularly, trisazo compounds represented by formulas (26) and (27) are particularly preferred. This is because it has a wide photosensitive wavelength range up to around 850 nm, and it becomes possible to prepare a photosensitive member having high sensitivity to LD light (780 to 850 nm) by mixing with a disazo pigment.

[0047]

Embedded image (Wherein, R ^{1 to} R ⁹ are a hydrogen atom, —CH ₃ , —C ₂ H
_5, -C ₃ H _7, a chlorine atom, a fluorine atom, an iodine atom, a bromine _{atom, CH 3 O-, C 2 H} 5 O-, C 3 H 7 O -, - NO 2,
Shown -CN, -CF ₃ or -OH, respectively. )

[0048]

Embedded image

[0049]

Embedded image

As the charge transport material used in the present invention, any known materials can be used. Specific examples thereof include the compounds shown in Table 17 having the basic structure represented by the following general formula 24 (Japanese Patent Application Laid-Open No.
No. 302260).

[0051]

Embedded image

[0052]

[Table 17- (1)]

[0053]

[Table 17- (2)]

[0054]

[Table 17- (3)]

[0055]

[Table 17- (4)]

[0056]

[Table 17- (5)]

[0057]

[Table 17- (6)]

[0058]

[Table 17- (7)]

[0059]

[Table 17- (8)]

[0060]

[Table 17- (9)]

[0061]

[Table 17- (10)]

[0062]

[Table 17- (11)]

[0063]

[Table 17- (12)]

As other charge transporting substances used in the electrophotographic photoreceptor of the present invention, for example, oxazole derivatives, imidazole derivatives, triphenylamine derivatives and the like can be used. Such compounds.

[0065]

Embedded image (Wherein, R ¹ represents a methyl group, an ethyl group, a 2-hydroxyethyl group or a 2-chloroethyl group, R ² represents a methyl group, an ethyl group, a benzyl group or a phenyl group, and R ³ represents a hydrogen atom , Chlorine atom, bromine atom, carbon number 1
4 represents an alkyl group, an alkoxyl group having 1 to 4 carbon atoms, a dialkylamino group or a nitro group. )

[0066]

Embedded image (Where Ar is a naphthalene ring, an anthracene ring,
Represents a styryl ring and a substituted product thereof, or a pyridine ring, a furan ring or a thiophene ring, and R represents an alkyl group or a benzyl group. )

[0067]

Embedded image (Wherein, R ¹ represents an alkyl group, a benzyl group, a phenyl group, a naphthyl group, R ₂ represents a hydrogen atom,
Represents an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a dialkylamino group, a diaralkylamino group or a diarylamino group; n represents an integer of 1 to 4;
In the above case, R ² may be the same or different. R ³ represents a hydrogen atom or a methoxy group. )

[0068]

Embedded image (Wherein, R ₁ represents an alkyl group having 1 to 11 carbon atoms, a substituted or unsubstituted phenyl group or a heterocyclic group,
R ^2, R ³ may be different from each other in the same, represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group, chloroalkyl group, or a substituted or unsubstituted aralkyl group, also, R ² And R ³ may combine with each other to form a nitrogen-containing heterocyclic ring. R ⁴ may be the same or different and represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group or a halogen atom. )

Embedded image (In the formula, R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group and a phenyl group, and R ² represents a hydrogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, or a halogen atom.)

[0069]

Embedded image (Wherein, R represents a hydrogen atom or a halogen atom, Ar represents a substituted or unsubstituted phenyl group, a naphthyl group,
Represents an anthryl group or a carbazolyl group. )

[0070]

Embedded image (Wherein, R ₁ represents a hydrogen atom, a halogen atom, a cyano group, an alkoxy group having 1 to 4 carbon atoms or an alkyl group having 1 to 4 carbon atoms, and Ar represents

Embedded image R ² represents an alkyl group having 1 to 4 carbon atoms; R ³ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms or a dialkylamino group; Or 2 and when n is 2, R ³ may be the same or different, and R ⁴ and R ^{5 each} represent a hydrogen atom,
Substitutions 4 to 4 also represent an unsubstituted alkyl group or a substituted or unsubstituted benzyl group. )

[0071]

Embedded image (Wherein, R is a carbazolyl group, a pyridine group, a thienyl group, an indolyl group, a furyl group or a substituted or unsubstituted phenyl group, a styryl group, a naphthyl group or an anthryl group, and these substituents are dialkylamino Group, an alkyl group, an alkoxy group, a carboxy group or an ester thereof, a halogen atom, a cyano group, an aralkylamino group, an N-alkyl-N-aralkylamino group, an amino group, a nitro group and an acetylamino group. Represents a group.)

[0072]

Embedded image (Wherein, R ¹ represents a lower alkyl group, a substituted or unsubstituted phenyl group or a benzyl group, and R ² and R ³
Represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, a halogen atom, a nitro group, an amino group or an amino group substituted with a lower alkyl group or a benzyl group;
Or an integer of 2. )

[0073]

Embedded image (Wherein, R ¹ represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom, and R ² and R ³ represent an alkyl group, a substituted or unsubstituted aralkyl group or a substituted or unsubstituted aryl group, R ⁴ represents a hydrogen atom or a substituted or unsubstituted phenyl group;
r represents a substituted or unsubstituted phenyl group or a naphthyl group. )

[0074]

Embedded image (Where n is an integer of 0 or 1, R ¹ is a hydrogen atom,
Represents an alkyl group or a substituted or unsubstituted phenyl group, Ar ¹ represents a substituted or unsubstituted aryl group,
R ⁵ represents an alkyl group containing a substituted alkyl group or a substituted or unsubstituted aryl group;

Embedded image9-anthryl group or substituted or unsubstituted carbazolyl
A group represented by R^TwoRepresents a hydrogen atom, an alkyl group,
Lucoxy group, halogen atom Represents an aralkyl group or a substituted or unsubstituted aryl group
Then R^ThreeAnd R^FourMay be the same or different, and
M may be an integer of 0, 1, 2, or 3.
If m is 2 or more, R^TwoAre the same but different
You may. When n is 0, A and R¹Is a joint ring
It may be formed. ]

[0075]

Embedded image (Wherein, R ¹ , R ² and R ³ represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a dialkylamino group or a halogen atom, and n represents 0 or 1)

[0076]

Embedded image (Wherein, R ¹ and R ² represent an alkyl group including a substituted alkyl group, or a substituted or unsubstituted aryl group;
A represents a substituted amino group, a substituted or unsubstituted aryl group or an allyl group. )

[0077]

Embedded image (Wherein, X represents a hydrogen atom, a lower alkyl group, a halogen atom, R represents an alkyl group including a substituted alkyl group,
Or A represents a substituted or unsubstituted aryl group, and A represents a substituted amino group or a substituted or unsubstituted aryl group. )

[0078]

Embedded image (However, in the formula, R ¹ represents a lower alkyl group, a lower alkoxy group or a halogen atom, n represents an integer of 0 to 4, R ² and R ³ may be the same or different, and a hydrogen atom,
Represents a lower alkyl group, a lower alkoxy group or a halogen atom. )

[0079]

Embedded image (Wherein, R ¹ , R ³ and R ⁴ represent a hydrogen atom, amino group, alkoxy group, thioalkoxy group, aryloxy group, methylenedioxy group, substituted or unsubstituted alkyl group, halogen atom or substituted or In the unsubstituted aryl group, R ² represents a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group, or a halogen atom, provided that R ¹ ,
R ² , R ^3, and R ⁴ exclude the case where all are hydrogen atoms.
Further, k, l, m and n are integers of ¹ , ² , 3 or 4, and when each is an integer of 2, 3 or 4, the above R ¹ , R ² , R
³ and R ⁴ may be the same or different. )

[0080]

Embedded image (Wherein, Ar represents a condensed polycyclic hydrocarbon group having 18 or less carbon atoms, and R ¹ and R ² represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a substituted Or an unsubstituted phenyl group, which may be the same or different.)

A-CH = CH-Ar-CH = CH-A wherein Ar is a substituted or unsubstituted aromatic carbon
A represents a hydrogen group, and A is (Where Ar 'is a substituted or unsubstituted aromatic hydrocarbon
R represents a group¹And R^TwoIs a substituted or unsubstituted alkyl
Group or a substituted or unsubstituted aryl group)
You. ]

[0081]

Embedded image (Wherein, Ar represents an aromatic hydrocarbon group, R represents a hydrogen atom, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and n represents 0 or 1,
m is 1 or 2, and when n = 0 and m = 1, Ar and R may form a ring together. )

Compounds represented by the general formula 25 include, for example, 9-ethylcarbazole-3-aldehyde-1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde-1-benzyl-1-phenylhydrazone. , 9-ethylcarbazole-3-aldehyde-
Examples include 1,1-diphenylhydrazone. Compounds represented by general formula 26 include, for example, 4-diethylaminostyryl-β-aldehyde-1-methyl-1-phenylhydrazone, 4-methoxynaphthalene-1-aldehyde-1-benzyl-1-phenylhydrazone and the like. There is.

Compounds represented by general formula 27 include, for example, 4-methoxybenzaldehyde-1-methyl-1
-Phenylhydrazone, 2,4-dimethoxybenzaldavido-1-benzyl-1-phenylhydrazone, 4-
Diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-methoxybenzaldehyde-1-benzyl-1- (4-methoxy) phenylhydrazone, 4-
Diphenylaminobenzaldehyde-1-benzyl-1
-Phenylhydrazone, 4-dibenzylaminobenzaldehyde-1,1-diphenylhydrazone and the like.
Compounds represented by general formula 28 include, for example, 1,1-bis (4-dibenzylaminophenyl) propane, tris (4-diethylaminophenyl) methane,
Examples include 1,1-bis (4-dibenzylaminophenyl) propane and 2,2'-dimethyl-4,4'-bis (diethylamino) -triphenylmethane. Examples of the compound represented by the general formula 29 include N-ethyl-3,6-tetrabenzylaminocarbazole.

The compounds represented by the general formula 30 include, for example, 9- (4-diethylaminostyryl) anthracene and 9-bromo-10- (4-diethylaminostyryl) anthracene. Examples of the compound represented by the general formula 31 include 9- (4-dimethylaminobenzylidene) fluorene and 3- (9-fluorenylidene) -9-ethylcarbazole.

The compounds represented by the general formula 33 include, for example, 1,2-bis (4-diethylaminostyryl) benzene and 1,2-bis (2,4-dimethoxystyryl) benzene. Compounds represented by general formula 34 include, for example, 3-styryl-9-ethylcarbazole,
3- (4-methoxystyryl) -9-ethylcarbazole and the like.

The compounds represented by the general formula 35 include, for example, 4-diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene,
-(4-diphenylaminostyryl) naphthalene, 1-
(4-Diethylaminostyryl) naphthalene and the like. Compounds represented by general formula 36 include, for example, 4 ′
-Diphenylamino-α-phenylstilbene, 4′-
And bis (methylphenyl) amino-α-phenylstilbene.

Compounds represented by the general formula 38 include, for example, 1-phenyl-3- (4-diethylaminostyryl) -5- (4-diethylaminophenyl) pyrazoline, 1-phenyl-3- (4-dimethylaminostyryl) ) -5- (4-dimethylaminophenyl) pyrazoline and the like. Compounds represented by general formula 39 include, for example, 2,5-bis (4-diethylaminophenyl) -1,3,4-oxadiazole, 2-N, N-diphenylamino-5- ( 4-diethylaminophenyl)
-1,3,4-oxadiazole, 2- (4-dimethylaminophenyl) -5- (4-diethylaminophenyl) -1,3,4-oxadiazole and the like.

Compounds represented by the general formula 40 include:
For example, 2-N, N-diphenylamino-5- (N-ethylcarbazol-3-yl) -1,3,4-oxadiazole, 2- (4-diethylaminophenyl) -5
(N-ethylcarbazol-3-yl) -1,3,4-
Oxadiazole and the like. Compounds represented by general formula 41 include N, N'-diphenyl-N, N '
-Bis (3-methylphenyl)-[1,1'-bisphenyl] -4,4'-diamine, 3,3'-dimethyl-
N, N, N ', N'-tetrakis (4-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine and the like.

The biphenylamine compound represented by the general formula 42 includes, for example, 4′-methoxy-N, N-diphenyl- [1,1′-biphenyl] -4-amine,
Methyl-N, N'-bis (4-methylphenyl)-
[1,1′-biphenyl] -4-amine, 4′-methoxy-N, N′-bis (4-methylphenyl)-[1,
1'-biphenyl] -4-amine and the like. Further, the triarylamine compound represented by the general formula 43 includes:
For example, there are 1-phenylaminopyrene, 1-di (p-tolylamino) pyrene and the like.

The diolefin aromatic compounds represented by the general formula (44) include, for example, 1,4-bis (4-diphenylaminostyryl) benzene, 1,4-bis [4-di (p-tolyl) amino [Styryl] benzene.
Examples of the styrylpyrene compound represented by the general formula 45 include 1- (4-diphenylaminostyryl) pyrene and 1- [4-di (p-tolyl) aminostyryl] pyrene.

These charge transporting substances can be used alone or in combination of two or more. In the present invention,
Oxidation potential +0.5 V (vs. SC
E) It is preferable to use the above compounds, and among them, the compounds represented by the general formulas 25 to 26, 28, 30, 34 to 36, and 41 to 44 are used to form an electrophotographic photosensitive member. By doing so, the chargeability and photosensitivity are excellent. In particular, an electrophotographic photoreceptor using the compound represented by the general formula 28 is preferable because it has particularly superior charge stability when repeatedly used as compared with others. The oxidation potential of the charge transporting material in the present invention is a half-wave potential in a generally known cyclic voltametery measurement, and the conditions are acetonitrile as a solvent, 0.1 M TEAP as an electrolyte, and a reference electrode. This is a value when a saturated calomel electrode (SCE) is used.

The single-layer type electrophotographic photoreceptor of the present invention has excellent charge stability even when repeatedly used by including an antioxidant in the photosensitive layer.

The antioxidants that can be used in the present invention include:
As antioxidants, ultraviolet absorbers and light stabilizers for plastics, rubber, petroleum, oils and fats, JP-A-57-122444, JP-A-60-188956, JP-A-63-18355, JP-A-63-18355 Phenols described in -18356, etc., paraphenylenediamines, hydroquinones, organic sulfur compounds, organic phosphorus compounds, hydroxyanisole, piperidine oxopiperazines, carotene, amines, tocophenols, Ni Known materials such as (II) complexes and sulfides can be used. In particular, compounds selected from the following compound groups represented by the following chemical formulas 7 to 18 are preferably used because of their high effects.

[0094]

Embedded image (Wherein, R _{1 to} R ₄ each represent a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; A cycloalkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group,
Substituted amino group, imino group, heterocyclic group, sulfoxide group,
Represents a sulfonyl group, an acyl group, or an azo group. The compound represented by the general formula (7) is described in US Pat.
No. 8906 and J.P. Am. Chem. Soc. , 55 .
1224 (1933) and the like.

[0095]

Embedded image (Wherein, R _{1 to} R ₄ each represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkoxy group, Group, substituted or unsubstituted aryloxy group, alkylthio group, arylthio group, alkylamino group, arylamino group, acyl group, alkylacylamino group, arylacylamino group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonamide group, Arylsulfonamide, alkylsulfamoyl, arylsulfamoyl, alkylsulfonyl, arylsulfonyl, alkyloxycarbonyl, aryloxycarbonyl, alkylacyloxy, arylacyloxy, silyl Or a heterocyclic group. However, R ₁
At least one of R ₄ is a group having a total of 4 or more carbon atoms. )

[0096]

Embedded image (Wherein, R _{1 to} R ₈ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents an alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, and a substituted or unsubstituted carbamoyl group.)

[0097]

Embedded image (Wherein, R _{1 to} R ₇ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents an alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, and a substituted or unsubstituted carbamoyl group.)

[0098]

Embedded image (Wherein, R _{1 to} R ₇ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents an alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, and a substituted or unsubstituted carbamoyl group.)

[0099]

Embedded image (Wherein, R _{1 to} R ₆ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents an alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, and a substituted or unsubstituted carbamoyl group.)

[0100]

Embedded image (Wherein, R _{1 to} R ₈ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, or a substituted or unsubstituted carbamoyl group.) The compound represented by Chemical Formula 13 is described in J. Am. Org. C
hem. , 51 . 1700 (1986); Am.
Chem. Soc. , 107 . 7053 (1985)
And so on.

[0101]

Embedded image

Embedded image (Wherein, R _{1 to} R ₁₀ and R _{11 to} R ₁₈ each represent a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl Group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted amino group, imino group, heterocyclic group, substituted or unsubstituted alkylthio group or arylthio group, sulfoxide Group,
Represents a sulfonyl group, an acyl group, or an azo group. )

[0102]

Embedded image

Embedded image (Wherein, R _{1 to} R ₈ and R _{9 to} R ₁₈ each represent a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group,
Substituted or unsubstituted aryl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted amino group, imino group, heterocyclic group, substituted or unsubstituted alkylthio group Represents an arylthio group, a sulfoxide group, a sulfonyl group, an acyl group, or an azo group. )

Embedded image (Wherein, R _{1 to} R ₅ each represent a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; A cycloalkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted amino group, an imino group, a heterocyclic group, a substituted or unsubstituted alkylthio or arylthio group, a sulfoxide group, a sulfonyl group,
Represents an acyl group or an azo group. )

Specific examples of the compounds represented by the general formulas 7 to 18 include, but are not limited to, those shown in the following Tables 18 to 27.

[Specific Examples of Compound of General Formula 7]

[Table 18- (1)]

[Table 18- (2)] [Specific Examples of Compound of General Formula 8]

[Table 19- (1)]

[Table 19- (2)]

[Table 19- (3)]

[Table 19- (4)]

[Table 19- (5)]

[Table 19- (6)]

[Table 19- (7)]

[Table 19- (8)]

[Table 19- (9)]

[Table 19- (10)]

[Table 19- (11)]

[Table 19- (12)]

[Table 19- (13)]

[Table 19- (14)]

[Table 19- (15)]

[Table 19- (16)]

[Table 19- (17)]

[Table 19- (18)]

[Table 19- (19)]

[Table 19- (20)]

[Table 19- (21)]

[Table 19- (22)]

[Table 19- (23)]

[Table 19- (24)]

[Table 19- (25)]

[Table 19- (26)]

[Table 19- (27)]

[Table 19- (28)]

[Table 19- (29)]

[Table 19- (30)]

[Table 19- (31)]

[Table 19- (32)]

[0105]

[Table 19- (33)]

[Table 19- (34)]

[Table 19- (35)]

[Table 19- (36)]

[Table 19- (37)]

[Table 19- (38)]

[Table 19- (39)]

[0106]

[Table 19- (40)]

[Table 19- (41)] [Specific Examples of Compound of General Formula 9]

[Table 20- (1)]

[Table 20- (2)]

[Table 20- (3)]

[Table 20- (4)]

[Table 20- (5)]

[Table 20- (6)]

[Table 20- (7)]

[Table 20- (8)]

[Table 20- (9)]

[Table 20- (10)]

[Table 20- (11)]

[Table 20- (12)]

[Table 20- (13)] [Specific Examples of Compound of General Formula 10]

[Table 21- (1)]

[Table 21- (2)] [Specific Examples of Compound of General Formula 11]

[Table 22- (1)]

[Table 22- (2)]

[Table 22- (3)]

[Table 22- (4)]

[Table 22- (5)]

[Table 22- (6)]

[Table 22- (7)] [Specific Examples of Compound of General Formula 12]

[Table 23- (1)]

[Table 23- (2)]

[Table 23- (3)]

[Table 23- (4)]

[Table 23- (5)] [Specific Examples of Compound of General Formula 13]

[Table 24- (1)]

[Table 24- (2)] [Specific examples of compounds of general formulas 14 and 15]

[Table 25- (1)]

[Table 25- (2)]

[Table 25- (3)]

[Table 25- (4)]

[Table 25- (5)]

[Table 25- (6)] [Specific Examples of Compounds of General Formulas 16 and 17]

[Table 26- (1)]

[Table 26- (2)]

[Table 26- (3)]

[Table 26- (4)]

[Table 26- (5)]

[Table 26- (6)]

[Table 26- (7)] [Specific Examples of Compound of General Formula 18]

[Table 27- (1)]

[Table 27- (2)]

[Table 27- (3)]

[Table 27- (4)]

[Table 27- (5)]

[Table 27- (6)]

[Table 27- (7)]

[Table 27- (8)]

[Table 27- (9)]

[Table 27- (10)]

[Table 27- (11)]

[Table 27- (12)]

Hereinafter, the present invention will be described with reference to FIGS. 1 to 4. Reference numeral 1 denotes a conductive support, and reference numeral 2 denotes a photoconductive layer according to the present invention. The electrophotographic photoreceptor of the present invention, as shown in FIGS.
As long as the photoconductive layer is a single layer type, any form may be used, and an undercoat layer 3 may be provided between the photoconductive layer and the conductive support in order to improve adhesion and charge blocking properties. Further, a protective layer 4 may be provided on the photoconductive layer in order to improve mechanical durability such as abrasion resistance.

Examples of the conductive support used in the electrophotographic photoreceptor of the present invention include metals and alloys such as aluminum, brass, stainless steel and nickel, and insulating supports such as polyethylene terephthalate, polypropylene, nylon, glass and paper. Metals such as aluminum, silver, gold and nickel or conductive materials such as indium oxide and tin oxide formed on the thin film, carbon black, indium oxide,
Examples thereof include a material in which a conductive powder such as tin oxide is dispersed in an appropriate resin to form a film, a paper subjected to a conductive treatment, and the like. The shape of the conductive support is not particularly limited, and a plate-like, drum-like, or belt-like material is used as necessary.

As the binder resin used in the present invention, known resins are used, and a high molecular polymer having insulating properties and high film forming ability is preferable. For example, polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyvinylidene chloride, Polyarylate resin, polycarbonate (bisphenol A
Type, bisphenol Z type), cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-
Vinyl carbazole, acrylic resin, silicone resin,
Examples include, but are not limited to, thermoplastic or thermosetting resins such as epoxy resins, melamine resins, urethane resins, phenolic resins, and alkyd resins.

To prepare the electrophotographic photoreceptor of the present invention,
The disazo pigment and the trisazo pigment were simultaneously mixed and pulverized by the above method, a charge transporting substance, a binder resin was added and mixed, and a dip coating method or a spray coat method or a bead coat method was used on the conductive support. It may be applied. Examples of the solvent for mixing and grinding include ketones, esters, alcohols, cyclic ethers, cyclic ketones, and the like. Preferably, cyclic ethers, cyclic ketones, and more preferably, tetrahydrofuran and cyclohexanone are used in view of the sensitizing effect. it can.

The ratio of the charge-generating substance and the binder resin used in the present invention is preferably in the range of 0.01 to 10 parts by weight based on 10 parts by weight of the simultaneously pulverized mixture of azo pigments. If it is less than the above range, the residual potential is large, and if it is more than the above range, the chargeability and the mechanical strength decrease. The ratio of the charge transport material and the binder resin used in the present invention is,
The charge transporting material is preferably in the range of 1 to 15 parts by weight based on 10 parts by weight of the binder resin. When the amount is less than the above range, the sensitivity is lowered, and when the amount is more than the above range, the charging property and the mechanical strength are deteriorated. The ratio of the antioxidant and the binder resin used in the present invention is 0.01 to 10 parts by weight of the antioxidant to the binder resin.
A range of 2 parts by weight is preferred. When the amount is less than the above range, the effect of improving the charging stability is small.

The photoconductive layer of the present invention has a thickness of 5 to 100 μm.
m, preferably in the range of 10 to 50 μm. 5μ
When the thickness is smaller than m, there is no mechanical durability, and when the thickness is larger than 100 μm, the residual potential increases.

[0113]

Next, the present invention will be described in more detail by way of examples.

Example 1 As a charge generating material, 5 parts by weight of a disazo pigment represented by the following formula and a 5 parts by weight of a trisazo pigment represented by the following formula were dispersed together with 70 parts by weight of methyl ethyl ketone for 5 days in a ball mill for simultaneous grinding and mixing treatment. And 100 parts by weight of a Z-type polycarbonate resin having a molecular weight of 60,000, 300 parts by weight of tetrahydrofuran, and 4-
Diethylaminobenzaldehyde-1-benzyl-1-
80 parts by weight of phenylhydrazone, hindered amine compound as antioxidant [Sanol LS-770 (manufactured by Sankyo)]
A coating solution for a photosensitive layer was prepared by adding 5 parts by weight of a solution containing 0.1 part by weight of silicone oil [KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.)]. The photosensitive layer coating solution thus obtained was coated on a 0.2 mm thick aluminum plate [A1080
(Manufactured by Sumitomo Light Metal Co., Ltd.)]
After drying for 20 minutes, a photosensitive layer having a thickness of 20 μm was formed. Thus, an electrophotographic photosensitive member of Example 1 was prepared.

Embedded image

Embedded image

Example 2 An electrophotographic photoreceptor of Example 2 was prepared in the same manner as in Example 1 except that the disazo pigment represented by Chemical Formula 46 was changed to the disazo pigment represented by Chemical Formula 48 below. did.

Embedded image

Example 3 In Example 1, except that the trisazo pigment represented by the formula (47) was changed to a trisazo pigment represented by the following formula (49),
An electrophotographic photosensitive member of Example 3 was prepared in the same manner as in Example 1.

Embedded image

Example 4 An electrophotographic photoreceptor of Example 4 was prepared in the same manner as in Example 1 except that the disazo pigment represented by Chemical Formula 46 was changed to the disazo pigment represented by Chemical Formula 50 below. did.

Embedded image

Example 5 In Example 1, except that the trisazo pigment represented by the formula (47) was changed to a trisazo pigment represented by the following formula (51),
An electrophotographic photosensitive member of Example 5 was prepared in the same manner as in Example 1.

Embedded image

Example 6 Example 6 was the same as Example 1 except that the input amounts of the disazo pigment represented by Chemical Formula 46 and the trisazo pigment represented by Chemical Formula 47, which were charge generating substances, were changed to 0.04 parts by weight and 0.04 parts by weight, respectively. The electrophotographic photoreceptor of Example 6 was prepared in the same manner as in Example 1.

Example 7 Example 7 was the same as Example 1 except that the charge amounts of the disazo pigment represented by Chemical Formula 46 and the trisazo pigment represented by Chemical Formula 47 were changed to 0.05 parts by weight and 0.05 parts by weight, respectively. In the same manner as in Example 1, an electrophotographic photosensitive member of Example 7 was prepared.

Example 8 Example 1 was the same as Example 1 except that the charge amounts of the disazo pigment represented by Chemical Formula 46 and the trisazo pigment represented by Chemical Formula 47 were changed to 50 parts by weight and 50 parts by weight, respectively. The electrophotographic photoreceptor of Example 8 was prepared in the same manner as described above.

Example 9 Example 9 was the same as Example 1 except that the amounts of the charge-generating substance, the disazo pigment of Chemical formula 46 and the trisazo pigment of Chemical formula 47, were changed to 75 parts by weight and 75 parts by weight, respectively. In the same manner as in the above, an electrophotographic photosensitive member of Example 9 was prepared.

Example 10 An electrophotographic photosensitive member of Example 10 was prepared in the same manner as in Example 1 except that the amount of the charge transporting substance was changed to 5 parts by weight.

Example 11 An electrophotographic photosensitive member of Example 11 was prepared in the same manner as in Example 1, except that the amount of the charge transporting material was changed to 10 parts by weight.

Example 12 An electrophotographic photosensitive member of Example 12 was prepared in the same manner as in Example 1, except that the amount of the charge transporting substance was changed to 150 parts by weight.

Example 13 An electrophotographic photosensitive member of Example 13 was prepared in the same manner as in Example 1, except that the amount of the charge transporting substance was changed to 200 parts by weight.

Example 14 Example 1 was repeated, except that methyl ethyl ketone was changed to 1,4-dioxane.
4 was prepared.

Example 15 An electrophotographic photosensitive member of Example 15 was prepared in the same manner as in Example 1, except that methylethylketone was changed to isophorone.

Example 16 Example 1 was repeated in the same manner as in Example 1 except that methyl ethyl ketone was changed to tetrahydrofuran.
6 was prepared.

Example 17 Example 17 was carried out in the same manner as in Example 1, except that methyl ethyl ketone was changed to cyclohexanone.
Was prepared.

Comparative Example 1 As a charge generating material, 5 parts by weight of the disazo pigment of the above formula and 5 parts by weight of the trisazo pigment of the above formula were separately dispersed together with 35 parts by weight of methyl ethyl ketone in a ball mill for 5 days, and then mixed. And a molecular weight of 6
100 parts by weight of Z-type polycarbonate resin, 300 parts by weight of tetrahydrofuran, Example 1 as a charge transport material
From 80 parts by weight of the compound used in the above, 5 parts by weight of a hindered amine compound [Sanol LS-770 (manufactured by Sankyo)] as an antioxidant, and 0.1 parts by weight of silicone oil [KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.)] In addition to this solution, a coating solution for a photosensitive layer was prepared. The coating liquid for a photosensitive layer thus obtained was formed into a film in the same manner as in Example 1, and an electrophotographic photosensitive member of Comparative Example 1 was prepared.

Comparative Example 2 As a charge generating material, 10 parts by weight of the disazo pigment represented by Chemical Formula 46 was dispersed in a ball mill for 5 days together with 70 parts by weight of methyl ethyl ketone, and 100 parts by weight of a Z-type polycarbonate resin having a molecular weight of 60,000 and 300 parts by weight of tetrahydrofuran Compound 80 used in Example 1 as a charge transport material
Parts by weight, 5 parts by weight of a hindered amine compound [Sanol LS-770 (manufactured by Sankyo)] as an antioxidant, and 0.1 part by weight of silicone oil [KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.)] A coating solution for a photosensitive layer was prepared. The coating liquid for a photosensitive layer thus obtained was formed into a film in the same manner as in Example 1 to prepare an electrophotographic photosensitive member of Comparative Example 2.

Comparative Example 3 As a charge generating material, 10 parts by weight of the trisazo pigment represented by Chemical Formula 47 was dispersed in a ball mill for 5 days together with 70 parts by weight of methyl ethyl ketone, and 100 parts by weight of a Z-type polycarbonate resin having a molecular weight of 60,000, 300 parts by weight of tetrahydrofuran
Parts by weight, compound 8 used in Example 1 as charge transport material
0 parts by weight, 5 parts by weight of a hindered amine compound [Sanol LS-770 (manufactured by Sankyo)] as an antioxidant, and 0.1 parts by weight of silicone oil [KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.)] Thus, a coating solution for a photosensitive layer was prepared. The coating liquid for a photosensitive layer thus obtained was formed into a film in the same manner as in Example 1 to prepare an electrophotographic photoreceptor of Comparative Example 3.

The electrostatic characteristics of the electrophotographic photosensitive member obtained as described above were measured at 25 ° C./50% RH under an environment of EPA-8.
100 (manufactured by Kawaguchi Electric Works) was measured by a dynamic method. First, after charging at an applied voltage of +6 KV for 10 seconds, dark decay was performed for 20 seconds, and exposure was performed for 30 seconds with white light from a halogen lamp at a surface illuminance of 10 lux. Similarly, charging and dark decay were performed, and exposure was also performed using a 780 nm monochromatic light source with a surface illuminance of 10 μW / cm ² . The charging potential is the surface potential V ₂ (V) 2 seconds after charging.
And the sensitivity is that the surface potential after exposure is 2 times the surface potential immediately before exposure.
Exposure E _1/2 (lux · sec)
[White light]) and E _1/2 (μJ / cm ² [monochromatic light])
The residual potential is the surface potential V 30 seconds after exposure with each light source.
₃₀ (V) was measured. Table 28 shows the results.

[0135]

[Table 28]

Examples 18 to 38 Electrophotographs of Examples 18 to 38 were carried out in the same manner as in Example 1 except that the antioxidants were changed to the antioxidants shown in Table 29 below. A photoreceptor was made.

[0137]

[Table 29]

Example 39 Example 3 was carried out in the same manner as in Example 25, except that the amount of the antioxidant was changed to 0.05 parts by weight.
9 were prepared.

Example 40 Example 40 was carried out in the same manner as in Example 25, except that the amount of the antioxidant was changed to 0.1 part by weight.
Was prepared.

Example 41 An electrophotographic photosensitive member of Example 41 was prepared in the same manner as in Example 25 except that the amount of the antioxidant was changed to 20 parts by weight.

Example 42 An electrophotographic photosensitive member of Example 42 was prepared in the same manner as in Example 25 except that the amount of the antioxidant was changed to 30 parts by weight.

Comparative Example 4 An electrophotographic photosensitive member of Comparative Example 4 was prepared in the same manner as in Example 1 except that no antioxidant was added.

Examples 18 to 4 obtained as described above
2. Electrostatic characteristics of the electrophotographic photosensitive members of Comparative Example 4 and Example 1 were measured by a dynamic method using EPA-8100 (manufactured by Kawaguchi Electric Works) in an environment of 25 ° C./50% RH. First, after charging for 10 seconds at an applied voltage of +6 KV, 2
Exposure was performed for 10 seconds with dark decay for 0 second and white light from a halogen lamp at a surface illuminance of 10 lux.
The charging potential is the saturation surface potential Vm for 10 seconds of charging.
(V), the sensitivity is expressed by an exposure amount E1 / 2 (lux.multidot.x) required for the surface potential after exposure to be 1/2 of the surface potential immediately before exposure.
sec (white light)) (before fatigue), and the above-mentioned charging to exposure is repeated 5,000 times to measure the stability of electrostatic characteristics (after fatigue; Vm ', E1 / 2'V30'). did. Table 30- (1) and Table 30- (2) show the results.

[0144]

[Table 30- (1)]

[0145]

[Table 30- (2)]

As is clear from the above results, it is found that the charging performance is remarkably improved by adding the antioxidant. Above all, in Examples 24 to 38 using the antioxidants represented by the general formulas 7 to 18, and in Examples 40 and 41 in which the addition amount is preferable, the chargeability is further improved, and the photosensitivity and the residual potential It is advantageous for

Comparative Example 5 As a charge generating material, 5 parts by weight of the disazo pigment represented by Chemical Formula 46 and 5 parts by weight of the trisazo pigment represented by Chemical Formula 47 were dispersed in a ball mill for 5 days together with 70 parts by weight of cyclohexanone.
The mixture was further diluted with 420 parts by weight of cyclohexanone to prepare a coating liquid for a charge generation layer. The coating liquid for a charge generation layer thus obtained was coated on the aluminum plate with a blade and dried at 100 ° C. for 10 minutes to form a 0.3 μm thick charge generation layer. Next, 100 parts by weight of a Z-type polycarbonate resin having a molecular weight of 60,000, 80 parts by weight of the compound used in Example 1 as a charge transporting substance, and silicone oil [KF-5
0 (manufactured by Shin-Etsu Chemical Co., Ltd.)] was dissolved in 300 parts by weight of dichloromethane to prepare a charge transport layer coating solution. The charge transport layer coating solution thus obtained was coated on the charge generation layer with a blade, and dried at 150 ° C. for 20 minutes to form a charge transport layer having a thickness of 20 μm. Created body.

The thus obtained multilayer electrophotographic photosensitive member of Comparative Example 5 and the single-layer electrophotographic photosensitive member of Example 25 were measured for spectral sensitivity by a static method. -600 V for the laminated electrophotographic photosensitive member of Comparative Example 5,
For the electrophotographic photoreceptor of Example 25, the applied voltage was adjusted so as to be +600 V, and thereafter, it was adjusted to 900 nm to 400 nm (20 n
Irradiated with monochromatic light that has been split in m units, the sensitivity (V ·
cm ² / μJ). FIG. 5 shows the result.

As a result,
It can be seen that the single-layer type photoreceptor of Example 25 according to the present invention shows a stable and high spectral sensitivity in a wide range of exposure wavelengths from a long wavelength to a short wavelength as compared with the laminated type photoreceptor of Comparative Example 5. .

[0150]

As described above, the electrophotographic photoreceptor of the present invention comprises a single pulverized mixture of a specific disazo pigment and a trisazo pigment, a charge transport material, a binder resin, and an antioxidant. By having it contained in the photoconductive layer, it has high sensitivity to light in a wide range from the visible region to the near-infrared region, and has stable chargeability even when used repeatedly.
It can be seen that there is no decrease in image density or background contamination.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an electrophotographic photosensitive member according to the present invention, in which a single photoconductive layer is provided on a conductive support.

FIG. 2 is a schematic diagram showing an example of the electrophotographic photoreceptor according to the present invention, in which an undercoat layer is provided between a conductive support and a photoconductive layer.

FIG. 3 is a schematic view showing an example of the electrophotographic photosensitive member according to the present invention, in which a protective layer is provided on a photoconductive layer.

FIG. 4 is a schematic view showing an example of the electrophotographic photosensitive member according to the present invention, in which an undercoat layer and a protective layer are provided at the same time.

FIG. 5 is a graph showing the spectral sensitivity of the electrophotographic photosensitive members according to Example 25 and Comparative Example 5.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive support 2 photoconductive layer 3 undercoat layer 4 protective layer

Continuation of front page (72) Inventor Yasuo Suzuki 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-5-297611 (JP, A) JP-A-5-297610 (JP, A) JP-A-2-154272 (JP, A) JP-A-4-310964 (JP, A) JP-A-3-132666 (JP, A) JP-A-4-195057 (JP, A) JP-A-3-7945 (JP, A) JP-A-5-204178 (JP, A) JP-A-4-136864 (JP, A) JP-A-5-127402 (JP, A) JP-A-3-293673 ( JP, A) JP-A-3-110566 (JP, A) JP-A-62-276563 (JP, A) JP-A-62-276560 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/00 CA (STN)

Claims (18)

(57) [Claims] 1. An electrophotographic photoreceptor comprising a photoconductive layer formed on a conductive support, wherein the photoconductive layer comprises at least one disazo pigment represented by the following general formula (1): An electrophotographic photosensitive member comprising a single layer containing a co-ground mixture with at least one kind of trisazo pigment represented by the general formula 2, a charge transport material, a binder resin, and an antioxidant. Embedded image Embedded image Wherein A, B and D represent a coupler residue represented by the following general formula 3, and R ₁ represents a hydrogen atom, a chlorine atom, a fluorine atom, an iodine atom, and a bromine. atom,
Indicates -NO ₂ or -CN. Embedded image ｛Wherein, X represents a naphthalene ring, an anthracene ring, a carbazole ring, a benzocarbazole ring, a polycyclic aromatic ring selected from a dibenzofuran ring and a dibenzothiophene ring, or a heterocyclic ring bonded to a benzene ring. And R ₂ and R ₃ represent a group selected from a hydrogen atom, a substituted or unsubstituted alkyl group, an aryl group and a heterocyclic group, and R ₂ and R ₃ represent a ring together with a nitrogen atom to be bonded. May be formed. R ₄ and R ₅ each represent a group selected from a substituted or unsubstituted alkyl group and an aryl group;
Represents a divalent group of an aromatic hydrocarbon or a divalent group of a heterocyclic ring containing a nitrogen atom in the ring, and R ₆ , R ₇ , R ₈ and R ₉ represent a hydrogen atom, a substituted or unsubstituted alkyl group, an aralkyl Group, represents a group selected from an aryl group and a heterocyclic group,
R ₈ and R ₉ may form a 5- or 6-membered ring. In this case, the 5- or 6-membered ring may have a condensed aromatic ring. Z is a naphthalene ring, an anthracene ring, a carbazole ring, a benzocarbazole ring formed by condensing with a benzene ring,
It indicates a residue necessary for forming a polycyclic aromatic ring or hetero ring selected from a dibenzofuran ring, a benzonaphthofuran ring and a dibenzothiophene ring. Ar ¹ and Ar ² are
An aromatic ring such as a benzene ring or a naphthalene ring or a substituted product thereof, and R ₁₀ and R _{11 each} represent a hydrogen atom, a lower alkyl group, a carboxyl group or an ester thereof. ｝) 2. The electrophotographic photosensitive member according to claim 1, wherein said trisazo pigment is a compound represented by the following general formula 4. Embedded image (Wherein, R ^{1 to} R ⁹ are a hydrogen atom, —CH ₃ , —C
_{2 H 5, -C 3 H 7} , a chlorine atom, a fluorine atom, an iodine atom,
A bromine _{atom, CH 3 -, C 2 H} 5 O-, C 3 H 7 O -, - N
Represents O ₂ , —CN, —CF ₃ or —OH. ) 3. The electrophotographic photoconductor according to claim 1, wherein the disazo pigment is a compound represented by the following general formula (5) and / or (6). Embedded image Embedded image 4. The electrophotographic photoreceptor according to claim 1, wherein the simultaneously pulverized mixture of the azo pigment is contained in an amount of 0.01 to 10 parts by weight based on 10 parts by weight of the binder resin. . 5. The electrophotographic photoreceptor according to claim 1, wherein the charge transporting material is contained in an amount of 1 to 15 parts by weight based on 10 parts by weight of the binder resin. 6. The electrophotographic photoreceptor according to claim 1, wherein the antioxidant is contained in an amount of 0.01 to 2 parts by weight based on 10 parts by weight of the binder resin. 7. The antioxidant according to the following general formula 7
The electrophotographic photoreceptor according to claim 1, comprising at least one compound represented by the following formula: Embedded image (Wherein, R _{1 to} R ₄ each represent a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; A cycloalkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted alkylthio group, a substituted or unsubstituted arylthio group,
Substituted amino group, imino group, heterocyclic group, sulfoxide group,
Represents a sulfonyl group, an acyl group, or an azo group. ) 8. The antioxidant according to the following general formula 8
The electrophotographic photoreceptor according to claim 1, comprising at least one compound represented by the following formula: Embedded image (Wherein, R _{1 to} R ₄ each represent a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkoxy group, Group, substituted or unsubstituted aryloxy group, alkylthio group, arylthio group, alkylamino group, arylamino group, acyl group, alkylacylamino group, arylacylamino group, alkylcarbamoyl group, arylcarbamoyl group, alkylsulfonamide group, Arylsulfonamide, alkylsulfamoyl, arylsulfamoyl, alkylsulfonyl, arylsulfonyl, alkyloxycarbonyl, aryloxycarbonyl, alkylacyloxy, arylacyloxy, silyl Or a heterocyclic group. However, R ₁
At least one of R ₄ is a group having a total of 4 or more carbon atoms. ) 9. The antioxidant according to the following general formula 9
The electrophotographic photoreceptor according to claim 1, comprising at least one compound represented by the following formula: Embedded image (Wherein, R _{1 to} R ₈ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents an alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, and a substituted or unsubstituted carbamoyl group.) 10. The electrophotographic photoreceptor according to claim 1, wherein the antioxidant contains at least one compound represented by the following general formula (10). Embedded image (Wherein, R _{1 to} R ₇ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents an alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, and a substituted or unsubstituted carbamoyl group.) 11. The electrophotographic photoconductor according to claim 1, wherein the antioxidant contains at least one compound represented by the following general formula (11). Embedded image (Wherein, R _{1 to} R ₇ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents an alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, and a substituted or unsubstituted carbamoyl group.) 12. The electrophotographic photoreceptor according to claim 1, wherein the antioxidant contains at least one compound represented by the following general formula 12. Embedded image (Wherein, R _{1 to} R ₆ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents an alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, and a substituted or unsubstituted carbamoyl group.) 13. The electrophotographic photoreceptor according to claim 1, wherein the antioxidant contains at least one compound represented by the following general formula (13). Embedded image (Wherein, R _{1 to} R ₈ each represent a hydrogen atom, a hydroxy group, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; Cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted or unsubstituted amino group, substituted or unsubstituted imino group, substituted or unsubstituted heterocyclic group, substituted or unsubstituted Represents an alkylthio group, a substituted or unsubstituted arylthio group, a substituted or unsubstituted acyl group, a substituted or unsubstituted sulfonyl group, a substituted or unsubstituted phosphonyl group, and a substituted or unsubstituted carbamoyl group.) 14. The electrophotographic photoreceptor according to claim 1, wherein the antioxidant contains at least one compound represented by the following general formula (14) or (15). Embedded image Embedded image (Wherein, R _{1 to} R ₁₀ and R _{11 to} R ₁₈ each represent a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl Group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted amino group, imino group, heterocyclic group, substituted or unsubstituted alkylthio group or arylthio group, sulfoxide Group,
Represents a sulfonyl group, an acyl group, or an azo group. ) 15. The electrophotographic photoreceptor according to claim 1, wherein the antioxidant contains at least one compound represented by the following general formula (16) or (17). Embedded image Embedded image (Wherein, R _{1 to} R ₈ and R _{9 to} R ₁₈ each represent a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group,
Substituted or unsubstituted aryl group, substituted or unsubstituted cycloalkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted aryloxy group, substituted amino group, imino group, heterocyclic group, substituted or unsubstituted alkylthio group Represents an arylthio group, a sulfoxide group, a sulfonyl group, an acyl group, or an azo group. ) 16. The electrophotographic photoconductor according to claim 1, wherein the antioxidant contains at least one compound represented by the following general formula (18). Embedded image (Wherein, R _{1 to} R ₅ each represent a hydrogen atom, a halogen atom, a hydroxy group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted group; A cycloalkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryloxy group, a substituted amino group, an imino group, a heterocyclic group, a substituted or unsubstituted alkylthio or arylthio group, a sulfoxide group, a sulfonyl group,
Represents an acyl group or an azo group. ) 17. The electron according to claim 1, wherein the co-milled mixture of the azo pigments is a co-milled mixture using at least one of a cyclic ether and a cyclic ketone as a dispersion solvent. Photoreceptor. 18. The electrophotographic photosensitive material according to claim 1, wherein the simultaneously pulverized mixture of the azo pigments has been subjected to simultaneous pulverization and mixing using at least one of tetrahydrofuran and cyclohexanone as a dispersion solvent. body.