JPS62115452A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To easily produce an electrophotographic sensitive body having satisfactory sensitivity by forming a photosensitive layer contg. a specific trisazo pigment on an electrically conductive support. CONSTITUTION:A photosensitive layer contg. a trisazo pigment represented by formula I (where each of R1-R3 is H, alkyl, alkoxy or halogen, at least one among R1-R3 is a substituent other than H, and A is a coupler residue) is formed on an electrically conductive support. The trisazo pigment is used as a charge generating substance in the photosensitive layer. A laminate type photosensitive layer 19 consisting of a charge generating layer 15 contg. the trisazo pigment 13 as the principal component and a charge transferring layer 17 contg. a charge transferring substance as the principal component may be formed on an electrically conductive support 11. Thus, a sensitive body is more easily produced than a conventional sensitive body and the resulting sensitive body has high sensitivity and superior properties. The characteristics of the sensitive body are stable even after repeated use.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a photoreceptor for electrophotography, and more particularly, to a photoreceptor for electrophotography.
The present invention relates to an electrophotographic photoreceptor provided with a photosensitive layer containing a trisazo pigment as a substance that generates charge carriers when irradiated with light (hereinafter referred to as a "charge-generating substance").

Traditionally, inorganic photosensitive materials such as selenium, selenium alloys, cadmium sulfide, and zinc oxide have been used as photoconductors for electrophotography. It is widely used because it has comprehensively excellent characteristics such as , dark decay, and sensitivity. However, since selenium-based photoreceptors are manufactured by vacuum evaporation, it is difficult to control their properties, the manufacturing cost is high, they are difficult to process into a belt shape due to their lack of flexibility, and they are susceptible to heat and mechanical shock. This poses problems such as restrictions on handling due to the sensitive nature of these substances.

In addition, as an organic photoreceptor that has excellent flexibility and is relatively easy to manufacture, it has a photosensitive layer made of a charge transfer complex of 2,4,7-trinitro-9-fluorenone and poly-N-vinylcarbazole. Some of them have been put into practical use, but their sensitivity was low and they were unsuitable as photoreceptors for high-speed copying machines.

In recent years, extensive research has been carried out to eliminate these drawbacks of photoreceptors, and among them, a functionally separated photoreceptor in which the generation of charge carriers and the transport of the generated charges are performed by separate substances has been attracting attention. The 0-functional separation type photoreceptor has a photosensitive layer in which a charge generation layer containing a charge generation substance that generates charge carriers upon irradiation with light and a charge transport layer containing a charge transport substance that transports the generated charges are laminated. There are laminated type photoreceptors that have a charge transport material, and dispersion type photoreceptors that have a charge generating substance dispersed in a charge transport medium that contains a charge transport material. Because of this, it is attracting attention as a photoreceptor for copying on plain paper.

This type of conventional laminated photoreceptor uses (I) a thin layer of a vacuum-deposited perylene derivative as a charge generation layer and an oxadiazole derivative as a charge transport layer (see U.S. Pat. No. 3,871,882); (2) A thin layer formed by coating an organic amine solution of chlordian blue as the charge generation layer and a hydrazone compound used as the charge transport layer (Japanese Patent Publication No. 55-4238
(see Publication No. 0) are known.

However, it is true that conventional laminated photoreceptors of this type have many advantages, but also have various drawbacks. In other words, it is a first-order defect.

The photoreceptor using the perylene derivative and oxadiazole derivative shown in (I) has a charge generation layer formed by vacuum deposition, which increases the manufacturing cost.

The photoreceptor using chlordiane blue and a hydrazone compound shown in (2) uses an organic amine (which is generally difficult to handle) as a coating solvent for forming a charge generation layer.
For example, it is necessary to use ethylenediamine), which has many disadvantages in producing photoreceptors.

As a photoreceptor that is easy to manufacture and has excellent sensitivity, a photoreceptor using a disazo pigment having a styrylstilbene skeleton as a charge generating substance (Japanese Patent Application Laid-open No. 133445/1982) is known. , a photoreceptor using a disazo pigment having a dibenzothiophene skeleton as a charge generating substance (JP-A-54-21728), a photoreceptor using a disazo pigment having a carbazole skeleton as a charge-generating substance (JP-A-53-95033) (Japanese Unexamined Patent Publication No. 54-132347), a photoreceptor using a disazo pigment having an oxadiazole skeleton (Japanese Unexamined Patent Publication No. 54-12742) ), a photoreceptor using a disazo pigment having a distyrylcarbazole skeleton (Japanese Patent Application Laid-Open No. 1987-
14967), a photoreceptor using a disazo pigment having a bisstilbene skeleton (Japanese Unexamined Patent Publication No. 54-17733), and a photoreceptor using a disazo pigment having a fluorenone skeleton (Japanese Unexamined Patent Publication No. 54-22834). It has been reported. However, it is true that these photoreceptors have advantages and disadvantages, and it has been desired to develop photoreceptors with even more excellent characteristics in order to meet various demands.

Purpose An object of the present invention is to provide an electrophotographic photoreceptor that is easy to manufacture and has sufficient sensitivity.

Ao-ichiyui.

The electrophotographic photoreceptor of the present invention has the general formula (I) (wherein R1, R, and R1 represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and A is a coupler residue) on a conductive support. (wherein at least one of R1, R2, and R1 is a substituent other than a hydrogen atom) is characterized by having a photosensitive layer containing a trisazo pigment.

Examples of the alkyl group of R1, R,, R1 in general formula (I) include methyl group, ethyl group, propyl group, butyl group, etc., and examples of the alkoxy group include methoxy group, ethoxy group, butoxy group, and halogen atom. Examples of the atom include a fluorine atom, a chlorine atom, and a bromine atom.

Further, as the coupler in general formula (I), for example, compounds having a phenolic hydroxyl group such as phenols and naphthols, aromatic amino compounds having an amino group or aminonaphthols having an amino group and a phenolic hydroxyl group, fatty acids, etc. Compounds having a group or aromatic enolic ketone group (compounds having an active methylene group) are used, and preferably, the coupler residue A has the following general formula (II), (III), (■), (
■), CVI), (■), (■), (IK), (X)
, (X[), (Xll).

＼Z／ [In the above formulas (n), (m), (IV) and (V).

X, Yl, Z, m and n each represent the following.

X: -OH, -N or -NH5O, -R.

(R and R2 represent hydrogen or a substituted or unsubstituted alkyl group, and R1 represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.) Y4: Hydrogen, halogen, substituted or unsubstituted Alkyl group, substituted or unsubstituted alkoxy group, carboxy group, sulfo group, substituted or unsubstituted sulfamoyl group or 100N-Y.

(R4 represents hydrogen, an alkyl group or a substituent thereof, a phenyl group or a substituent thereof, Y2 is a hydrocarbon cyclic group or a substituent thereof, a heterocyclic group or a substituent thereof, k<@ a hydrogen cyclic group or a substituent thereof , a heterocyclic group or a substituent thereof, a styryl group or a substituent thereof, R6 represents hydrogen, an alkyl group, a phenyl group or a substituent thereof, or R6 and R6 together with the carbon atoms bonded to them form a ring. Z: a hydrocarbon ring or a substituent thereof, or a heterocycle or a substituent thereof n: an integer of 1 or 2 m: an integer of 1 or 2] [In formulas (Vl) and (■), R7 represents a substituted or unsubstituted hydrocarbon group, or is the same as above. ] ri [In the formula, R represents an alkyl group, a carbamoyl group, a carboxyl group, or an ester thereof, and Ar represents a hydrocarbon ring group or a substituent thereof, or is the same as above. ] [In the above formulas (IK) and (X), R9 represents hydrogen or a substituted or unsubstituted hydrocarbon group, and Ar2 represents a hydrocarbon ring group or a substituted product thereof. ] Z in the general formula (n), (m), (IV) or (V)
Examples of the hydrocarbon ring include a benzene ring and a naphthalene ring, and examples of the heterocycle include an indole ring, a carbazole ring, a benzolane ring, and a dibenzofuran ring. Examples of substituents on the ring of Z include halogen atoms such as chlorine atoms and bromine atoms.

Examples of the hydrocarbon ring group in Y2 or R5 include phenyl group, naphthyl group, anthryl group, pyrenyl group, etc.
Examples of the heterocyclic group include a pyridyl group, a chenyl group, a furyl group, an indolyl group, a benzofuranyl group, a carbazolyl group, and a dibenzofuranyl group.
Examples of the ring formed by combining 5 and R6 include a fluorene ring and the like.

Examples of substituents on the hydrocarbon ring group or heterocyclic group of Y2 or R6 or the ring formed by R6 and R6 include a methyl group and an ethyl group.

Alkyl groups such as propyl and butyl groups, methoxy groups,
Alkoxy groups such as ethoxy, propoxy and butoxy groups; halogen atoms such as chlorine and bromine; dialkylamino groups such as dimethylamino and diethylamino groups; halomethyl groups such as trifluoromethyl; nitro and cyano groups; Carboxyl group or its ester.

Examples include hydroxyl group, -8o, and sulfonic acid groups such as Na.

Examples of substituents for the phenyl group of R4 include halogen atoms such as chlorine atoms and bromine atoms.

Representative examples of the hydrocarbon group in R7 or R9 are:
Examples include alkyl groups such as methyl, ethyl, propyl and butyl groups, aryl groups such as phenyl, and substituted products thereof.

As the substituent in R1 or the hydrocarbon group of R1,
Examples include alkyl groups such as methyl, ethyl, propyl, and butyl groups; alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy; halogen atoms such as chlorine and bromine; hydroxyl and nitro groups. .

Typical examples of the hydrocarbon ring group in Ar or Ar are phenyl group, naphthyl group, etc.
Substituents for these groups include alkyl groups such as methyl, ethyl, propyl, and butyl, alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy, nitro, chlorine, bromine, etc. Examples include halogen atoms, dialkylamino groups such as cyano groups, dimethylamino groups, and diethylamino groups.

Furthermore, among X, a hydroxyl group is particularly suitable.

Among the above coupler residues, preferred is the general formula (
m), (VI), (■), (■), (W) and (
X), and among these, those in which X in the general formula is a hydroxyl group are preferred. Also, among these, a coupler residue represented by the general formula (X[) \Z (y x and Z are the same as above) is preferred, and more preferably a general formula (z, y, and R2 are the same as above). ) is a coupler residue represented by

Furthermore, among the above preferred coupler residues, general formula (XIII) or (XIV)\Zノ\Z/ (Z, R, , R, and R6 are the same as above, and R1゜ is (Examples include substituents for Y2.) Those represented by the following are suitable.

Specific examples of the trisazo pigment used in the present invention as described above are shown below. For the sake of simplicity, the central skeleton and the coupler residue A are shown separately, and the trisazo pigment is shown by the combination of their respective numbers.

(Example) Trisazo pigment (I-4) The number 1 in parentheses indicates the central skeleton number, 4 indicates the coupler residue number,
shows.

(Left below) Shi'zume [Odeshi Encounter] L&-N=N
-e-N+ N= N- N=N- -N= N+ N+ N= N- 'CH.

5 ◎-CzHs -N=N+N unit N=N- -N= N-@-N-o-N= N- Raw"" KoL punch l1 type% formula% Raw■"Kolshishi Aoi1 Shikku -N=N
-@-N-@-N= N- (blank space below) -shi'',! %LJIα-"-m- 142r) mini x ajii 21-"-1-cr
l-o-c 161 HO-? (CO-@-CM) By using the trisazo pigment of the present invention as described above, an extremely highly sensitive electrophotographic photoreceptor can be easily produced.

In the electrophotographic photoreceptor of the present invention, a trisazo pigment is used as a charge generating substance in the photosensitive layer, and a typical structure of this photoreceptor is shown in FIGS. 1 and 2.

The photoreceptor shown in FIG. 1 is a laminated photosensitive layer 1 consisting of a charge generation layer 15 mainly composed of a trisazo pigment 13 and a charge transport layer 17 mainly composed of a charge transport substance on a conductive support 11.
9.

In the photoreceptor shown in FIG. 1, imagewise exposed light passes through the charge transport layer and reaches the charge generation layer 15, where charge generation occurs in the trisazo pigment 13, while the charge transport layer 17
The mechanism is such that the charge is injected and transported, and the charge necessary for light attenuation is generated by the trisazo pigment 13, and the charge is transported by the charge transport layer 17.

The photoreceptor shown in FIG. 2 has a photosensitive layer 19' mainly composed of a trisazo pigment 13, a charge transport material, and an insulating binder on a conductive support 11. Again, the trisazo pigment 13 is a charge generating substance. In other photoreceptors, the charge generation layer and charge transport layer may be reversed as shown in FIG.

The thickness of the photosensitive layer is as shown in FIG. 1, and the thickness of the charge generation layer 15 is preferably 0.01 to 5μ, more preferably 0.05μ.
~2μ. If the thickness is less than 0.01 μm, charge generation will not be sufficient, and if it is more than 5 μm, the residual potential will be too high for practical use.

The thickness of the charge transport layer 17 is preferably 3 to 50 microns, more preferably 5 to 30 microns. If the thickness is less than 3 μm, the amount of charge will be insufficient, and if it is more than 50 μm, the residual potential will be too high to be practical.

The charge generation layer 15 is mainly composed of the trisazo pigment represented by the above general formula, and may further contain a binder, a plasticizer, and the like. Further, the proportion of the trisazo pigment in the charge generation layer is preferably 30% by weight or more, more preferably 50% by weight or more.
% by weight or more.

The charge transport layer 17 is mainly composed of a charge transport substance and a binder, and may further contain a plasticizer. The proportion of charge transport material in the charge transport layer is from 10 to 95% by weight, preferably from 30 to 90% by weight. When the proportion of the charge transport substance is less than 10% by weight, almost no charge is transported, and when it is more than 95% by weight, the mechanical strength of the photoreceptor film is so poor that it cannot be put to practical use.

In the case of the photoreceptor shown in FIG. 2, the thickness of the photosensitive layer 19' is preferably 3 to 50 microns, more preferably 5 to 30 microns. Further, the proportion of the trisazo pigment in the photoreceptor 19' is preferably 50% by weight or less, more preferably 20% by weight or less, and the proportion of the charge transport material is preferably 1% by weight or less.
It is 0 to 95% by weight, more preferably 30 to 90% by weight.

The gist of the present invention is to use a specific trisazo pigment represented by the general formula (I) as a charge generating substance in an electrophotographic photoreceptor, and to use other materials such as a conductive support and a charge transporting substance. Any conventionally known components can be used, and these will be specifically explained below.

The conductive support used in the photoreceptor of the present invention includes a metal plate made of aluminum, copper, zinc, etc., a plastic sheet or plastic film made of polyester, and aluminum.

A material coated with a conductive material such as SnO, or paper treated with conductivity is used.

Binders include polyamide and polyurethane.

Examples include condensation resins such as polyester, epoxy resin, phenoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide. All resins can be used.

Examples of plasticizers include halogenated paraffins, polychlorinated biphenyls, dimethylnaphthalene, and dibutyl phthalate. In addition, silicone oil or the like may be added to improve the surface properties of the photoreceptor.

Charge transport materials include hole transport materials and electron transport materials.

Examples of the hole transport substance include the following compounds.

9-ethylcarbazole-3-aldehyde, 1 methyl-
1-phenylhydrazone, 9-ethylcarbazole-3
-aldehyde 1-benzyl-1-phenylhydrazone,
9-ethylcarbazole-3-aldehyde 1,1-diphenylhydrazone, 4-di-noble thylaminostyrene-β-
Aldehyde 1-methyl-1-phenylhydrazone, 4-
Methoxynaphthalene-1-aldehyde 1-benzyl-1
-Phenylhydrazone, 4-methoxybenzaldehyde 1-methyl-1-phenylhydrazone, 2,4-dimethoxybenzaldehyde 1-benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde 1゜1-
Diphenylhydrazone, tris(4-diethylaminophenyl)methane, 1,1-bis(4-dibenzylaminophenyl)propane, 9-(4-diethylaminostyryl)anthracene, 9-(4-dimethylaminobenzylidene)fluorene, 3- (9-fluorenylidene)
-9-ethylcarbazole, 1,2-bis(4-diethylaminostyryl)benzene, 1,2-bis(2,4-
dimethoxystyryl)benzene, 3-styryl-9-ethylcarbazole, 3-(4-methoxystyryl)-9
-Ethylcarbazole, 4-diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilbene, 1-(4-diphenylaminostyryl)naphthalene, 4'-diphenylamino-α-phenylstilbene, 4'-methyl Phenylamino-α-phenylstilbene, 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)
Pyrazoline, 1-phenyl-3-(4-dimethylaminostyryl)-5-(4-dimethylaminophenyl)pyrazoline, 2,5-bis(4-diethylaminophenyl)
-1,3,4-oxadiazole, 2,5-bis[4-
(4-diethylaminostyryl)phenyl]-1,3,
Examples include low molecular weight compounds such as 4-oxadiazole, tri-P-tolylamine, and triphenylamine. Further, polymeric compounds such as poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, pyrene formaldehyde resin, and ethylcarbazole formaldehyde resin can also be used.

Examples of the electron transport substance include chloranil, bromoanil, tetracyanoethylene, tetracyanoquinone dimethane, 2,4,7-dolinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone,
2,4゜5.7-titranitroxanthone, 2.4.8
-Trinidrothioxanthone, 2,6.8-trinitro-4H-indeno(I,2-b)thiophen-4-one, 1,3.7-trinitrodibenzothiophene-5,5
- Dioxide, etc.

These charge transport substances may be used alone or in combination of two or more.

In any of the photoreceptors obtained in one or more of the above methods, an adhesive layer or a barrier layer may be provided between the conductive support and the photosensitive layer, if necessary. Suitable materials for these layers include polyamide, nitrocellulose, aluminum oxide, and the like, and the film thickness is preferably 1 μm or less.

In order to produce the photoreceptor shown in FIG. 1, a trisazo pigment is deposited on a conductive support using the vacuum deposition method described in U.S. Pat. No. 3,973,959, U.S. Pat. Alternatively, fine particles of the trisazo pigment are dispersed in a suitable solvent in which a binder is dissolved, if necessary, and this is coated on a conductive support and dried, if necessary.

For example, the surface is finished by a method such as puff polishing as shown in JP-A No. 51-90827, or a solution containing a charge transport substance and a binder is applied and dried after adjusting the film thickness. It will be done.

The photoreceptor shown in FIG. 2 can be prepared by dispersing a fine powder of trisazo pigment in a solution containing a charge transporting substance and a binder, and applying and drying this onto a conductive support.

In either case, the trisazo pigment used in the present invention is used after being ground to a particle size of 5 μm or less, preferably 2 μm or less, using a ball mill or the like. The coating method is carried out by conventional means such as doctor blade, dipping, wire bar, etc.

To perform copying using the photoreceptor of the present invention, the surface of the photoreceptor layer is charged and exposed, and then developed, and if necessary,
This is achieved by transferring to paper or the like.

As is clear from the above explanation and the examples below,
The electrophotographic photoreceptor of the present invention uses a trisazo pigment having a triphenylamine skeleton as a charge generating substance, so it is easier to manufacture than conventional photoreceptors, has high sensitivity, and can be used repeatedly. It has excellent properties such as stable properties during use.

EXAMPLES Next, the present invention will be specifically explained using Examples, but the embodiments of the present invention are not limited thereby.

Example 1 76 parts by weight of trisazo pigment & (I-4), 1260 parts by weight of a tetrahydrofuran solution (solid content concentration 2%) of polyester resin (Vylon 200 manufactured by Toyobo Co., Ltd.), and 3700 parts by weight of tetrahydrofuran were ground in a ball mill. The resulting dispersion was applied using a doctor blade onto the aluminum surface of an aluminum-deposited polyester base (conductive support) and air-dried to form a charge generation layer with a thickness of about 1 μm.

On this charge generation layer, 2 parts by weight of 9-ethylcarbazole-3-aldehyde 1-methyl-1-phenylhydrazone, 2 parts by weight of polycarbonate resin (Teijin Panlite -1300) and 16 parts by weight of tetrahydrofuran were applied as a charge transporting material. A solution containing the above components was mixed and dissolved using a doctor blade, and dried at 80°C for 2 minutes and then at 105°C for 5 minutes to form a charge transport layer with a thickness of about 20 μm. A photoconductor Nα1 was prepared.

Examples 2 to 5 Photoreceptors &2 to 5 were prepared in the same manner as in Example 1, except that the trisazo pigment shown in Table 1 below was used instead of the trisazo pigment & (I-4) used in Example 1. did.

Examples 6 to 10 Example 1 except that 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)pyrazoline was used as the charge transport substance and the trisazo pigment shown in Table 1 below was used. In the same manner as above, photoconductor &6~10
It was created.

Examples 11 to 15 Photoreceptors &11 to 15 were prepared in the same manner as in Example 1, except that 9-(4-diethylaminostyryl)anthracene was used as the charge transport substance and the trisazo pigment shown in Table 1 below was used.
15 was created.

Examples 16 to 20 A photoreceptor Na16 was prepared in the same manner as in Example 1, except that 4'-diphenylamino-α-phenylstilbene was used as the charge transport substance and the trisazo pigment shown in Table 1 below was used.
~20 were created.

For these photoreceptors Nα1 to 20, electrostatic copying
-Paper testing device (-Kawaguchi Electric Seisakusho, 5P428 type)
Using a -6KV corona discharge for 20 seconds to make it negatively charged, it was left in a dark place for 20 seconds, the surface potential Vpo (V) at that time was measured, and then the surface was illuminated with a tungsten lamp. Light was irradiated at 4.5 lux, and the time (seconds) until the surface potential became 1/2 of Vpo was determined, and exposure: lE1/2 (lux/second) was calculated. The results are shown in Table-1.

(The following is a blank space) Table 1 Furthermore, the photoconductors NCh4 and Nα7 of the present invention were installed in a Ricoh Co., Ltd. copying machine M5 type, and an image was produced for 1 time.
The copying process was repeated 0,000 times, and as a result, neither photoreceptor changed due to repeated copying processes, and clear images were obtained. From this, it can be understood that the photoreceptor of the present invention is also excellent in durability.

[Brief explanation of drawings]

FIGS. 1 and 2 are enlarged sectional views showing an example of the structure of the photoreceptor of the present invention. 11... Conductive support 13... Trisazo pigment 15... Charge generation layer 17... Charge transport layer 19
．． 19'...Photosensitive layer

Claims (1)

[Claims] 1. General formula (I) ▲Mathematical formula, chemical formula, table, etc. are present on the conductive support▼(I) (In the formula, R_1, R_2, R_3 are hydrogen atoms, alkyl groups, alkoxy groups , represents a halogen atom, and A represents a coupler residue.However, at least one of R_1, R_2, and R_3 is a substituent other than a hydrogen atom.) Having a photosensitive layer containing a trisazo pigment represented by An electrophotographic photoreceptor characterized by: