JPH07199492A - Electrophotographic photoreceptor - Google Patents

Abstract

PURPOSE:To provide an electrophotographic photoreceptor with high sensitivity and to enhance the stability of the photoreceptor when it is repeatedly used by providing on an electrically conductive support a single photoconductive layer containing a mixture of disazo pigment and trisazo pigment which are crushed at the same time, a hole transporting material, an organic acceptor compound and a binding resin. CONSTITUTION:This electrophotographic photoreceptor has a photoconductive layer on an electrically conductive support. The photoconductive layer contains a mixture of at least one kind of disazo pigment represented by formula I and at least one kind of trisazo pigment represented by formula II which are crushed at the same time; an organic hole transporting material; an organic acceptor compound; and a binding resin. In formulae I and II, Ar<1>-Ar<3> represent a predetermined coupler residue and may be the same or different; R<1> and R<2> represent hydrogen atom, halogen atom, a trifluoromethyl group, a nitro group, or a cyano group; and R<3> represents hydrogen atom, chlorine atom, fluorine atom, iodine atom, bromine atom, -NO2, or -CN.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an electrophotographic photoreceptor,
More specifically, the present invention relates to a single-layer type organic electrophotographic photoreceptor useful for electrophotographic copying machines, printers and the like.

[0002]

Conventionally, as photoconductive materials used for electrophotographic photoreceptors, 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, the inorganic photoconductive material has problems such as photosensitivity, thermal stability, durability, and toxicity. For example, selenium has a drawback that it is easily crystallized by heat, stains, and the like, and its characteristics are easily deteriorated. In contrast to the electrophotographic photoreceptor using this inorganic photoconductive material, the organic photoconductive material has advantages such as excellent film forming properties, easy production, high design flexibility, lower cost, and no pollution. Therefore, in recent years, electrophotographic photoreceptors using organic photoconductive materials have been actively developed. The electrophotographic photoreceptor using the organic photoconductive material includes a function-separated photoreceptor in which a charge generation layer and a charge transport layer are laminated, and a single-layer photoreceptor in which a charge generation material is dispersed in a resin binder. Among them, the laminated-type photoconductor has been put into practical use in many cases because of its higher sensitivity.

For example, Japanese Examined Patent Publication No. 55-42380 describes a multi-layer type photoconductor in which chlordian blue and a hydrazone compound are combined, and a charge generating substance used in the multi-layer photoconductor is Japanese Patent Laid-Open No. 53-133445. ,
JP-A-54-21728, JP-A-54-21283
No. 4, etc., and as the charge transport material, JP-A-58-198043 and JP-A-58-19935.
It is described in Japanese Patent Publication No. 2 and the like.

However, the charge transporting material contained in the charge transporting layer of the laminated type photoconductor is required to have high charge mobility in order to achieve high sensitivity, but most charge transporting materials having high charge mobility are required. Since it has a hole-transporting property, the photoconductor that has been put to practical use is limited to the negative charging type. Most of the negative charging type photoconductors use negative corona discharge at the time of use, so that they generate a large amount of ozone and are not only harmful to the human body, but also react with the photoconductor. The life of the photoconductor itself is also shortened. In order 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 equipment, but it complicates the process and system. There are drawbacks such as doing.

On the other hand, the single-layer type photoconductor is generally known as a positive charging type photoconductor, for example, Japanese Patent Publication No. 50-1.
Polyvinylcarbazole described in JP-A-0496 and 2,
A photoreceptor containing 4,7-trinitro-9-fluorenone, a photoreceptor obtained by sensitizing polyvinylcarbazole 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
A photoconductor comprising a charge-generating substance and a charge-transporting substance described in Japanese Patent No. 0330, and a perylene pigment and a charge-transporting substance described in JP-A-63-271461, JP-A-1-118143, and JP-A-3-56961. There is proposed a photoconductor made of phthalocyanine compound and a photoconductor made of a binder resin described in JP-A-3-65961. However, these single-layer type photoconductors are inadequate particularly in terms of sensitivity and are inferior to the laminated type photoconductors.

Further, in recent years, as the copying machines have become more complex and more sophisticated, a photoconductor corresponding to the copying machines having analog and digital functions has been developed. In this case, the characteristics required for the photoconductor are to support the digital function,
It is desired that the LD laser light source has a high sensitivity in the wavelength, that is, the near infrared region, and that the white light source has a high sensitivity in the visible region, in order to support the analog function.

As such a photoreceptor, there is disclosed in Japanese Patent Laid-Open No. 63-
236047, JP-A-63-243950, JP-A-63-243951, JP-A-1-31
There has been proposed a laminated body photoreceptor having a wide spectral sensitivity from the visible region to the near infrared region by mixing a pigment having a sensitivity in the visible region and a pigment having a sensitivity in the near infrared region described in Japanese Patent No. 5752. However, in the case of these laminated types, in addition to the above-mentioned problem of ozone generation, the charge transporting substance in the upper layer absorbs light, so that it has a defect that the photosensitivity is deteriorated particularly in the short wavelength region. However, it is not always sufficient to have a wide spectral sensitivity from the visible region to the near infrared region, and there is an optical problem that buffering is likely to occur due to the interface between the charge generation layer and the charge transport layer. there were. In addition, in the case of a laminated type photoreceptor, it is generally necessary to reduce the film 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 the atmosphere and environment, and it is necessary to coat the photosensitive layer twice or three times or more, which greatly affects the yield and the manufacturing cost.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of these circumstances and has a high sensitivity, particularly in the visible region to the near infrared region, and is also excellent in stability during repeated use. It is an object of the present invention to provide a single-layer type electrophotographic photoreceptor.

[0009]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a mixture of a disazo pigment and a trisazo pigment simultaneously pulverized and mixed on a conductive support, a hole transporting material, and an organic material. The inventors have found that an electrophotographic photoconductor provided with a single photoconductive layer containing an acceptor compound and a binder resin is suitable for the above purpose, and completed the present invention.

That is, according to the present invention, in a photoconductor for electrophotography, which comprises a photoconductive layer formed on a conductive support, the photoconductive layer contains at least one specific disazo pigment and at least one. An electrophotographic photoreceptor comprising a single layer containing a co-ground mixture of a trisazo pigment of one species, an organic hole transfer material, an organic acceptor compound and a binder resin.

The electrophotographic photoreceptor of the present invention comprises, in a single photoconductive layer, a disazo pigment sensitive to visible light and a trisazo pigment sensitive to so-called near infrared light having a wavelength of 700 nm or more. Since it is configured to contain a pulverized product simultaneously mixed with, it exhibits high sensitivity to a wide range of light from visible light to near infrared light. This sensitizing effect will be clarified in Examples described later, but by mixing and pulverizing the disazo pigment and the trisazo pigment at the same time by applying mechanical energy, the sensitivity is significantly sensitized as compared with the case of each pigment alone. This is different from the previously proposed mixing effect of the combination of pigments.

The mixing ratio of the disazo pigment and the trisazo pigment used in the present invention is an optimum value in consideration of the characteristics (sensitivity, charging characteristics, gas resistance) required by the photoconductor depending on the type of pigment to be mixed. Can be selected individually,
Generally, the weight ratio is preferably 0.01 ≦ disazo pigment / (disazo pigment + trisazo pigment) ≦ 0.99. When it is lower than 0.01, the sensitivity sensitizing effect is small, and when it is higher than 0.99, the sensitizing effect and the gas resistance are less improved. Further, considering the uniformity of the 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 ball mill, a vibration mill, a disk vibration mill, an attritor, a sand mill, a paint shaker, a jet mill, an ultrasonic dispersion method, etc. Any pulverizing and mixing means that gives mechanical energy such as friction, stretching, impact and vibration can be used. Further, it is preferable that a desired amount of the disazo pigment and the desired amount of the trisazo pigment are put in the same container, and the above mechanical energy is simultaneously applied in the presence of a dispersion solvent described later to mix and pulverize them for 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) is used. And a disazo pigment represented by the following general formula 1 which has a high charge generation ability, and particularly the following general formula 2 which is sensitive to light having a wavelength of 700 nm or more.
A co-ground mixture with a trisazo pigment represented by

[Chemical 1]

[Chemical 2]

{However, in the above Chemical Formulas ¹ and ² , Ar ¹ and Ar ²
And Ar ³ represent a coupler residue represented by the following general formulas 3 to 10, and may be the same or different. Also, R ¹
And R ² represents a hydrogen atom, a halogen atom, a trifluoromethyl group, a nitro group, or a cyano group, and R ³ represents a hydrogen atom, a chlorine atom, a fluorine atom, an iodine atom, a bromine atom, or -N.
Indicates O ₂ or —CN.

[Chemical 3] [However, in the formula, X ¹ , Y ¹ and Z each represent the following. ^{X 1: -OH, -N (R} 4) (R 5), or -NHSO ₂ -
R ⁶ (provided that R ⁴ and R ⁵ represent a hydrogen atom, an acyl group, or a substituted or unsubstituted alkyl group, and R ⁶ represents a substituted or unsubstituted aryl group) Y ¹ : hydrogen atom, halogen atom , A substituted or unsubstituted alkyl group, an alkoxy group, a carboxy group, a sulfone group, a benzimidazolyl group, a substituted or unsubstituted sulfamoyl group, or —CON (R ⁷ ) (Y ² ).
(However, R ⁷ represents a hydrogen atom, an alkyl group or a substituted product thereof, or a phenyl group or a substituted product thereof, and Y ² is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or -N. = C (R ⁸ ) (R ⁹ ), where R ⁸
Is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or a styryl group or a substituted product thereof, R
⁹ is a hydrogen atom, an alkyl group or a substituted product thereof, or
Represents a phenyl group or a substitution product thereof, or R ⁸
And R ⁹ may form a ring with the carbon atom attached to them. 》. ) Z: represents a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof. ]

[0016]

[Chemical 4] [However, in the formula, R ¹⁰ , R ¹¹ , Y ¹ and n represent the following, respectively. n: integer of 1 to 4, R ¹⁰ : hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, R
¹¹ : hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylsulfonyl group, substituted or unsubstituted alkylmercapto group, halogen atom, substituted or unsubstituted aryl group, A substituted or unsubstituted acyl group, cyano group,
Represents a nitro group and a substituted or unsubstituted amino group,
When n is an integer of 2 to 4, R ¹¹ may be the same or different. Y ¹ : represents the same as the above chemical formula 3. ]

[Chemical 5]

[Chemical 6] [In the formulas 5 and 6, R ¹² represents a substituted or unsubstituted hydrocarbon group. ]

[Chemical 7]

[Chemical 8] [In the formulas 7 and 8, R ¹³ represents an alkyl group, a carbamoyl group, a carboxy group, or an ester thereof, and Ar ⁴ represents a substituted or unsubstituted aromatic hydrocarbon group. ]

[0017]

[Chemical 9]

[Chemical 10] [In the formulas 9 and 10, X ² represents a divalent group of an aromatic hydrocarbon or a divalent group of a heterocycle. ]}

Next, specific examples of the couplers of the above-mentioned disazo pigments and trisazo pigments used in the electrophotographic photoreceptor of the present invention, that is, Ar ¹ -H, Ar ² -H and Ar.
Specific examples of ^3- H are shown in Tables 1 to 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]

Of the above-mentioned azo pigments and disazo pigments, the compounds represented by the following formulas 12 and 13 are particularly preferable. These compounds have high sensitivity in the visible range, and when mixed with a trisazo pigment at the same time by pulverizing and mixing, the stability of the pigment dispersion coating liquid is good, good film formation is possible, and significant sensitization is possible. You can expect an effect.

[0045]

[Chemical 12]

[Chemical 13]

As the trisazo pigment, a compound represented by the following general formula 11 is preferable, and especially
And are preferred. This is because the trisazo compound represented by the general formula 11 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,
The simultaneous pulverization and mixing with the disazo pigment makes it possible to prepare a photoconductor having high photosensitivity in a wide range from the visible region to the near infrared region. Further, the trisazo compound represented by the formulas 26 and 27 is particularly preferable. This is because it has a wide photosensitive wavelength range up to around 850 nm, and by mixing with a disazo pigment, it becomes possible to prepare a photoreceptor having high sensitivity to LD light (780 to 850 nm).

[0047]

[Chemical 11] (However, in the formula, R ^{1 to} R ⁹ are a hydrogen atom, —CH ₃ , or —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]

[Chemical formula 26]

[0049]

[Chemical 27]

As the organic hole-transporting substance used in the present invention, any known substance can be used. Specific examples thereof include, for example, the compounds shown in Table 17 having a basic structure represented by the following general formula 28 (JP-A-1).
-302260 gazette).

[0051]

[Chemical 28]

[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 the organic acceptor compound used in the electrophotographic photosensitive member of the present invention, any known compounds can be used, but in particular, compounds represented by the following general formulas 14 to 27 are used in combination. And the manifestation of the effect is remarkable.

[Chemical 14] (In the formula, R ₁ is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted phenyl group, an alkoxycarbonyl group, an N-alkylcarbamoyl group,
A cyano group or a nitro group, n is an integer of 1 to 3,
However, X is However, R ₃ may be linked to each other. )

[0066]

[Chemical 15] (In the formula, Ar represents a substituted or unsubstituted aromatic group, and X represents a cyano group or an alkoxycarbonyl group.)

[0067]

Embedded image Ar—CH═C (COOR) ₂
(In the formula, Ar represents a substituted or unsubstituted aromatic group and R represents an alkyl group. However, R may combine with each other to form a ring.)

[0068]

[Chemical 17] (In the formula, X represents a sulfur or selenium atom, and Y
Represents a substituted or unsubstituted alkyl group, aryl group or cyano group, R represents a substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, cyano group, nitro group, halogen atom or hydrogen atom, n Represents 1, 2, or 3. )

[0069]

Embedded image Ar—CH═CHNO ₂ (wherein Ar represents a substituted or unsubstituted aromatic group).

[0070]

[Chemical 19] (In the formula, R ₁ and R ₂ represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a heteroaromatic ring group.)

[0071]

[Chemical 20] (In the formula, R ₁ is a hydrogen atom, a halogen atom, an alkyl group,
A substituted or unsubstituted phenyl group, R ₂ is a hydrogen atom,
A substituted or unsubstituted alkyl group, a substituted or unsubstituted phenyl group, a halogen atom, an alkoxycarbonyl group, an N-alkylcarbamoyl group, a cyano group, or a nitro group, and n represents an integer of 1 to 3. )

[0072]

[Chemical 21] (In the formula, R ₃ is a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted phenyl group, a halogen atom, an alkoxycarbonyl group, an N-alkylcarbamoyl group, a cyano group, or a nitro group, and n is 1 Represents an integer from 3 to 3.)

[0073]

[Chemical formula 22] (In the formula, R ₁ and R ₂ represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted polycyclic aromatic group, or a substituted or unsubstituted heterocyclic group.)

[0074]

[Chemical formula 23]

[0075]

[Chemical formula 24]

[0076]

[Chemical 25]

[0077]

[Chemical formula 26]

[0078]

[Chemical 27] (In the formula, X represents O or NR, and R represents a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group.)

Specific examples of the compound represented by the general formula 14 include those shown in Table 18 below.

[Table 18- (1)]

[Table 18- (2)]

[Table 18- (3)]

[Table 18- (4)]

Specific examples of the compound represented by the general formula 15 include those shown in Table 19 below.

[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)]

Specific examples of the compound represented by the general formula 16 include those shown in Table 20 below.

[Table 20- (1)]

[Table 20- (2)]

[Table 20- (3)]

[Table 20- (4)]

Further, specific examples of the compound represented by the general formula 17 include those shown in the following Table 21.

[0083]

[Table 21- (1)]

[0084]

[Table 21- (2)]

[0085]

[Table 21- (3)]

[0086]

[Table 21- (4)]

[0087]

[Table 21- (5)]

Further, specific examples of the compound represented by the general formula 18 include those shown in Table 22 below.

[Table 22- (1)]

[0089]

[Table 22- (2)]

[0090]

[Table 22- (3)]

[0091]

[Table 22- (4)]

[0092]

[Table 22- (5)]

Further, specific examples of the compound represented by the general formula 19 include those shown in Table 23 below.

[Table 23- (1)]

[0094]

[Table 23- (2)]

[0095]

[Table 23- (3)]

[0096]

[Table 23- (4)]

[0097]

[Table 23- (5)]

[0098]

[Table 23- (6)]

[0099]

[Table 23- (7)]

[0100]

[Table 23- (8)]

[0101]

[Table 23- (9)]

Further, specific examples of the compound represented by the general formula 20 include those shown in Table 24 below.

[Table 24- (1)]

[Table 24- (2)]

[Table 24- (3)]

[Table 24- (4)]

Further, specific examples of the compound represented by the general formula 21 include those shown in Table 25 below.

[Table 25- (1)]

Further, specific examples of the compound represented by the general formula 22 include those shown in Table 26.

[Table 26- (1)]

[0105]

[Table 26- (2)]

[0106]

[Table 26- (3)]

[0107]

[Table 26- (4)]

[0108]

[Table 26- (5)]

[0109]

[Table 26- (6)]

[0110]

[Table 26- (7)]

[0111]

[Table 26- (8)]

[0112]

[Table 26- (9)]

[0113]

[Table 26- (10)]

[0114]

[Table 26- (11)]

[0115]

[Table 26- (12)]

[0116]

[Table 26- (13)]

[0117]

[Table 26- (14)]

[0118]

[Table 26- (15)]

[0119]

[Table 26- (16)]

[0120]

[Table 26- (17)]

[0121]

[Table 26- (18)]

[0122]

[Table 26- (19)]

[0123]

[Table 26- (20)]

[0124]

[Table 26- (21)]

[0125]

[Table 26- (22)]

[0126]

[Table 26- (23)]

[0127]

[Table 26- (24)]

[0128]

[Table 26- (25)]

Specific examples of the compounds represented by the general formulas 23 to 26 are shown in Tables 27 to 30, respectively.
The items shown in are listed.

[0130]

[Table 27]

[0131]

[Table 28]

[0132]

[Table 29]

[0133]

[Table 30]

Specific examples of the compound represented by the general formula 27 include those shown in Table 31 below.

[Table 31- (1)]

[Table 31- (2)]

[Table 31- (3)]

These organic acceptor compounds may be used alone or in admixture of two or more.

The present invention will be described below with reference to FIGS. 1 to 4. Reference numeral 1 denotes a conductive support, and 2 denotes a photoconductive layer according to the present invention. The electrophotographic photosensitive member 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 the adhesiveness and the charge blocking property. Further, a protective layer 4 may be provided on the photoconductive layer in order to improve mechanical durability such as abrasion resistance.

As the conductive support used in the electrophotographic photoreceptor of the present invention, a metal or alloy such as aluminum, brass, stainless steel, nickel, etc., an insulating support such as polyethylene terephthalate, polypropylene, nylon, glass, paper, etc. A thin film of a metal such as aluminum, silver, gold, or nickel, or a conductive material such as indium oxide or tin oxide, carbon black, indium oxide,
Examples include conductive powder such as tin oxide dispersed in a suitable resin to form a film, and paper subjected to a conductive treatment. The shape of the conductive support is not particularly limited, and a plate-shaped, drum-shaped, or belt-shaped material is used as necessary.

As the binder resin used in the present invention, known binder resins are used, but a high molecular polymer having an insulating property and a 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-
Vinylcarbazole, acrylic resin, silicone resin,
Examples thereof include, but are not limited to, thermoplastic or thermosetting resins such as epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.

To prepare the electrophotographic photosensitive member of the present invention,
The disazo pigment and the trisazo pigment are simultaneously mixed and pulverized by the above-mentioned method, an organic hole-transporting substance, an organic acceptor compound, and a binder resin are added and mixed, and a dipping coating method or a spray coating method is applied on a conductive support. It may be applied using a bead coating method or the like. Examples of the solvent when mixed and pulverized include ketones, esters, alcohols, cyclic ethers, cyclic ketones, etc., preferably cyclic ethers, cyclic ketones, and more preferably tetrahydrofuran or cyclohexanone in view of the expression of the sensitizing effect. it can.

The ratio of the charge generating substance to the binder resin used in the present invention is preferably 0.01 to 10 parts by weight based on 10 parts by weight of the binder resin in the pulverized mixture of the 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 charging property and the mechanical strength are lowered. The ratio of the organic hole transfer material to the binder resin used in the present invention is 1 to 10 parts by weight of the organic hole transfer material to the binder resin.
A range of 15 parts by weight is preferred. If it is less than the above range, the sensitivity is lowered, and if it is more than the above range, the charging property and mechanical strength are deteriorated.

The ratio of the organic acceptor compound and the binder resin used in the present invention is preferably in the range of 1 to 15 parts by weight based on 10 parts by weight of the binder resin. If it is less than the above range, the chargeability will deteriorate due to repeated use, and if it is more than the above range, the sensitivity and mechanical strength will deteriorate.

The film thickness of the photoconductive layer of the present invention is 5 to 100 μm.
m, preferably 10 to 50 μm. 5μ
If it is thinner than m, it has no mechanical durability, and if it is thicker than 100 μm, the residual potential increases.

[0143]

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

Example 1 Coupler No. 1 was used as the charge generating substance. 17 and No. 24
5 parts by weight of the asymmetric disazo pigment represented by Chemical formula 1 (R ¹ = R ² = H) and coupler No. Chemical formula 2 using 70
5 parts by weight of the trisazo pigment represented by (R ³ = H) was dispersed with 70 parts by weight of tetrahydrofuran in a ball mill for 5 days and subjected to simultaneous pulverization and mixing treatment. 300 parts by weight, 50 parts by weight of a stilbene compound of Exemplified Compound No. III-59 as an organic hole transfer substance, 20 parts by weight of a compound represented by the following structural formula 29 as an organic acceptor compound, silicone oil [KF-50
(Manufactured by Shin-Etsu Chemical Co., Ltd.)] In addition to 0.1 parts by weight of the solution, a photosensitive layer coating liquid was prepared. The photosensitive layer coating liquid thus obtained was blade-coated on an aluminum plate having a thickness of 0.2 mm [A1080 (Sumitomo Light Metal Co., Ltd.)], 1
It was dried at 50 ° C. for 20 minutes to form a photosensitive layer having a thickness of 20 μm, and the electrophotographic photosensitive member of Example 1 was prepared.

[Chemical 29]

Example 2 In Example 1, the asymmetric disazo pigment was used as coupler No. 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 1 (R ¹ = R ² = H) was used instead of 30.

Example 3 In Example 1, the trisazo pigment was used as a coupler N.
o. An electrophotographic photosensitive member of Example 3 was prepared in the same manner as in Example 1 except that the trisazo pigment represented by Chemical Formula 2 (R ³ = H) was changed to 214.

Example 4 In Example 1, the asymmetric disazo pigment was used as coupler No. An electrophotographic photosensitive member of Example 4 was prepared in the same manner as in Example 1 except that the symmetrical disazo pigment represented by Chemical formula 1 (R ¹ = R ² = H) was used.

Example 5 In Example 1, the trisazo pigment was used as a coupler N.
o. Example 5 was repeated in the same manner as in Example 1 except that the trisazo pigment represented by Chemical formula 2 (R ³ = H) was used.
An electrophotographic photoconductor of was prepared.

Example 6 In Example 1, the charged amounts of the asymmetric disazo pigment and the trisazo pigment were 0.04, respectively.
An electrophotographic photosensitive member of Example 6 was prepared in the same manner as in Example 1 except that the amount was changed to 0.04 parts by weight.

Example 7 In Example 1, the charge amounts of the asymmetric disazo pigment and the trisazo pigment, which are charge generating substances, were each 0.05.
An electrophotographic photosensitive member of Example 7 was prepared in the same manner as in Example 1 except that the amount was changed to 0.05 part by weight.

Example 8 Example 8 was carried out in the same manner as in Example 1 except that the charged amounts of the asymmetric disazo pigment and trisazo pigment, which were charge generating substances, were changed to 50 parts by weight and 50 parts by weight, respectively. An electrophotographic photoconductor of was prepared.

Example 9 Example 9 was repeated in the same manner as in Example 1 except that the charge amounts of the asymmetric disazo pigment and the trisazo pigment, which were charge generating substances, were changed to 75 parts by weight and 75 parts by weight, respectively. An electrophotographic photoconductor of 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 organic acceptor compound added 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 organic acceptor compound added 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 organic acceptor compound added 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 organic acceptor compound added was changed to 200 parts by weight.

Examples 14 to 27 In Example 1, the organic acceptor compounds are shown in Table 32.
Electrophotographic photoreceptors of Examples 14 to 27 were prepared in the same manner as in Example 1 except that the compounds shown in FIG.

Comparative Example 1 In Example 1, the coupler N was used as the charge generating substance.
o. 17 and No. 5 parts by weight of the asymmetric disazo pigment represented by Chemical formula 1 (R ¹ = R ² = H) and coupler N
o. 5 parts by weight of the trisazo pigment represented by Chemical formula 2 (R ³ = H) using 70 were separately dispersed in a ball mill for 5 days together with 35 parts by weight of tetrahydrofuran, and then they were mixed to give Z-type polycarbonate resin 100 parts by weight, tetrahydrofuran 300 parts by weight, Compound 8 used in Example 1 as an organic hole transfer material
In addition to 0 parts by weight, a solution consisting of 20 parts by weight of the compound represented by the structural formula 29 as an organic acceptor compound, and 0.1 parts by weight of silicone oil [KF-50 (manufactured by Shin-Etsu Chemical Co., Ltd.)] A coating liquid was prepared. The coating solution for 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 1.

Comparative Example 2 In Example 1, the coupler No. 17 and No. 24
10 parts by weight of the asymmetric disazo pigment represented by Chemical formula 1 (R ¹ = R ² = H) using An electrophotographic photosensitive member of Comparative Example 2 was prepared in the same manner as in Example 1 except that the trisazo pigment represented by Chemical Formula 2 (R ³ = H) was used.

COMPARATIVE EXAMPLE 3 In Example 1, the coupler No. 17 and No. 24
Without the asymmetric disazo pigment represented by Formula 1 (R ¹ = R ² = H) using Chemical formula 2 using 70
An electrophotographic photosensitive member of Comparative Example 3 was prepared in the same manner as in Example 1 except that the trisazo pigment represented by (R ³ = H) was changed to 10 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 the organic acceptor compound was not added.

The electrostatic characteristics of the electrophotographic photosensitive member obtained as described above were measured with EPA-8 under an environment of 25 ° C./50% RH.
100 (manufactured by Kawaguchi Electric Mfg. Co., Ltd.) was used and the measurement was performed by the dynamic method. First, after charging for 10 seconds with an applied voltage of +6 KV, dark decay for 20 seconds, and then apply monochromatic light to the surface illuminance of 10 μm.
Exposure was performed with a 780 nm monochromatic light source of W / cm ² . The surface potential Vs (V) after 10 seconds from the start of charging, the surface potential V ₀ (V) after dark decay for 20 seconds, and the sensitivity are required so that the surface potential after exposure becomes half of the surface potential immediately before exposure. The exposure amount E _1/2 (μJ / cm ² ) was measured. In addition, as characteristics after repeated use, Vs (V), V ₀ (V), and Vs (V) after repeating the above-mentioned series of operations of charging and exposure 5000 times,
E _1/2 (μJ / cm ² ) was measured. Table 32 shows the results.

[0163]

[Table 32- (1)]

[0164]

[Table 32- (2)]

[0165]

As described above, the electrophotographic photosensitive member of the present invention comprises a co-ground mixture of a specific disazo pigment and trisazo pigment, an organic hole transfer material, an organic acceptor compound, and a binder resin. It can be seen that the inclusion of the above in a single photoconductive layer has a high sensitivity to light in a wide range from the visible region to the near infrared region and is excellent in stability during repeated use.

[Brief description of 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 view showing an example of an electrophotographic photosensitive member 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 an 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 an electrophotographic photosensitive member according to the present invention in which an undercoat layer and a protective layer are provided at the same time.

[Explanation of symbols]

 1 conductive support 2 photoconductive layer 3 subbing layer 4 protective layer

Claims (19)

[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 and An electron comprising a single layer containing a co-ground mixture with at least one trisazo pigment represented by the general formula 2, an organic hole transfer material, an organic acceptor compound, and a binder resin. Photoreceptor. [Chemical 1] [Chemical 2] {However, in the above Chemical Formulas 1 and 2, Ar ¹ , Ar ² and Ar ³ are
It represents a coupler residue represented by the following general formulas 3 to 10, and may be the same or different. Further, R ¹ and R ² represent a hydrogen atom, a halogen atom, a trifluoromethyl group, a nitro group, or a cyano group, and R ³ is a hydrogen atom, a chlorine atom, a fluorine atom, an iodine atom, a bromine atom, or -NO ₂ Or-CN
Indicates. [Chemical 3] [However, in the formula, X ¹ , Y ¹ and Z each represent the following. ^{X 1: -OH, -N (R} 4) (R 5), or -NHSO ₂ -
R ⁶ (provided that R ⁴ and R ⁵ represent a hydrogen atom, an acyl group, or a substituted or unsubstituted alkyl group, and R ⁶ represents a substituted or unsubstituted aryl group) Y ¹ : hydrogen atom, halogen atom , A substituted or unsubstituted alkyl group, an alkoxy group, a carboxy group, a sulfone group, a benzimidazolyl group, a substituted or unsubstituted sulfamoyl group, or —CON (R ⁷ ) (Y ² ).
(However, R ⁷ represents a hydrogen atom, an alkyl group or a substituted product thereof, or a phenyl group or a substituted product thereof, and Y ² is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or -N. = C (R ⁸ ) (R ⁹ ), where R ⁸
Is a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof, or a styryl group or a substituted product thereof, R
⁹ is a hydrogen atom, an alkyl group or a substituted product thereof, or
Represents a phenyl group or a substitution product thereof, or R ⁸
And R ⁹ may form a ring with the carbon atom attached to them. 》. ) Z: represents a hydrocarbon ring group or a substituted product thereof, a heterocyclic group or a substituted product thereof. ] [Chemical 4] [However, in the formula, R ¹⁰ , R ¹¹ , Y ¹ and n represent the following, respectively. n: integer of 1 to 4, R ¹⁰ : hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, R
¹¹ : hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, substituted or unsubstituted alkylsulfonyl group, substituted or unsubstituted alkylmercapto group, halogen atom, substituted or unsubstituted aryl group, A substituted or unsubstituted acyl group, cyano group,
Represents a nitro group and a substituted or unsubstituted amino group,
When n is an integer of 2 to 4, R ¹¹ may be the same or different. Y ¹ : represents the same as the above chemical formula 3. ] [Chemical 5] [Chemical 6] [In the formulas 5 and 6, R ¹² represents a substituted or unsubstituted hydrocarbon group. ] [Chemical 7] [Chemical 8] [In the formulas 7 and 8, R ¹³ represents an alkyl group, a carbamoyl group, a carboxy group, or an ester thereof, and Ar ⁴ represents a substituted or unsubstituted aromatic hydrocarbon group. ] [Chemical 9] [Chemical 10] [In the formulas 9 and 10, X ² represents a divalent group of an aromatic hydrocarbon or a divalent group of a heterocycle. ]} 2. The trisazo pigment has the general formula 11 below.
The electrophotographic photosensitive member according to claim 1, which is a compound represented by: [Chemical 11] (However, in the formula, R ^{1 to} R ⁹ are hydrogen atoms, —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
O _2, -CN, represent -CF _3, or -OH. ) 3. The electrophotographic photoreceptor according to claim 1, wherein the disazo pigment is a compound represented by the following general formula 12 and / or 13. [Chemical 12] [Chemical 13] 4. The electrophotographic photosensitive member according to claim 1, wherein the simultaneous 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 photosensitive member according to claim 1, wherein the organic acceptor compound is contained in a proportion of 1 to 15 parts by weight with respect to 10 parts by weight of the binder resin. 6. The electrophotographic photoreceptor according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 14. [Chemical 14] (In the formula, R ₁ is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted phenyl group, an alkoxycarbonyl group, an N-alkylcarbamoyl group,
A cyano group or a nitro group, n is an integer of 1 to 3,
However, X is However, R ₃ may be linked to each other. ) 7. The electrophotographic photoreceptor according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 15. [Chemical 15] (In the formula, Ar represents a substituted or unsubstituted aromatic group, and X represents a cyano group or an alkoxycarbonyl group.) 8. The electrophotographic photoreceptor according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 16. Embedded image Ar—CH═C (COOR) ₂
(In the formula, Ar represents a substituted or unsubstituted aromatic group and R represents an alkyl group. However, R may combine with each other to form a ring.) 9. The electrophotographic photosensitive member according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 17. [Chemical 17] (In the formula, X represents a sulfur or selenium atom, and Y
Represents a substituted or unsubstituted alkyl group, aryl group or cyano group, R represents a substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group, cyano group, nitro group, halogen atom or hydrogen atom, n Represents 1, 2, or 3. ) 10. The electrophotographic photoreceptor according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 18. Embedded image Ar—CH═CHNO ₂ (wherein Ar represents a substituted or unsubstituted aromatic group). 11. The electrophotographic photosensitive member according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 19. [Chemical 19] (In the formula, R ₁ and R ₂ represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, or a heteroaromatic ring group.) 12. The electrophotographic photosensitive member according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 20. [Chemical 20] (In the formula, R ₁ is a hydrogen atom, a halogen atom, an alkyl group,
A substituted or unsubstituted phenyl group, R ₂ is a hydrogen atom,
A substituted or unsubstituted alkyl group, a substituted or unsubstituted phenyl group, a halogen atom, an alkoxycarbonyl group, an N-alkylcarbamoyl group, a cyano group, or a nitro group, and n represents an integer of 1 to 3. ) 13. The electrophotographic photoreceptor according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 21. [Chemical 21] (In the formula, R ₃ is a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted phenyl group, a halogen atom, an alkoxycarbonyl group, an N-alkylcarbamoyl group, a cyano group, or a nitro group, and n is 1 Represents an integer from 3 to 3.) 14. The organic acceptor compound is
A compound represented by the general formula 22
The electrophotographic photoreceptor according to claim 1, wherein [Chemical formula 22] (However, in the formula, R₁And R₂Is a substituted or unsubstituted
Nyl group, substituted or unsubstituted polycyclic aromatic group, or substituted
Alternatively, it represents an unsubstituted heterocyclic group. ) 15. The electrophotographic photosensitive member according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 23. [Chemical formula 23] 16. The electrophotographic photoreceptor according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 24. [Chemical formula 24] 17. The electrophotographic photosensitive member according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 25. [Chemical 25] 18. The electrophotographic photoreceptor according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 26. [Chemical formula 26] 19. The electrophotographic photosensitive member according to claim 1, wherein the organic acceptor compound is a compound represented by the following general formula 27. [Chemical 27] (In the formula, X represents O or NR, and R represents a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group.)