JPS5890644A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic receptor high in sensitivity and durability, by adding a specified bisazo pigment to a layer, especially, to a charge generating layer, and forming a laminated photoconductive layer composed of the charge generating layer and a charge transfer layer. CONSTITUTION:At least one of bisazo compds. represented by formulaI(Cp is a group of formula II, III, or IV; R5 is H or alkyl; R6 is alkyl; R7, R8 are each optionally substd. alkyl or aralkyl or aryl; X is an atomic group necessary to complete an optionally substd. aromatic hydrocarbon ring or hetero ring; and R1-R4 are each H, halogen, or a monovalent org. group, such as alkyl, alkoxy, or acetyl) is added to a layer formed on a conductive substrate, especially, to the charge generating layer of a laminated photoconductive layer, thus permitting the obtained photoreceptor to be enhanced in chargeing characteristics, photosensitivity, etc., and superior in durability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a specific bisazo pigment.

Conventionally, electrophotographic photoreceptors made of inorganic photoconductive materials include selenium, cadmium sulfide, zinc oxide, etc.
O is widely used.

On the other hand, as electrophotographic photoreceptors made of organic photoconductive substances, photoconductive polymers such as poly-N-vinylcarbazole and λ5-bis(P-diethylamζnophenyl')-1,3,4-oxa Those using low-molecular organic photoconductive substances such as diazole, and those using combinations of organic photoconductive substances with various dyes and pigments are known.

Electrophotographic photoreceptors using organic photoconductive substances have poor film-forming properties and can be controlled by coating, making it possible to provide photoreceptors with extremely high productivity and low cost. Further, it has the advantage that color sensitivity can be freely controlled by selecting the sensitizer such as dye-pigment to be used, and a wide range of studies have been made to date.

However, they tend to suffer from poor sensitivity and durability), and so far only a few have been put into practical use.

The purpose of the present invention is, firstly, to provide an electrophotographic photoreceptor containing a specific bisazo pigment, secondly to provide a highly sensitive electrophotographic photoreceptor, and thirdly to provide a highly durable electrophotographic photoreceptor. It states that it provides electrophotographic photoreceptors.

This object of the present invention is achieved by an electrophotographic photoreceptor having, as a photosensitive layer, a layer containing at least one bisazo pigment represented by the following general formula (1).

General formula (1) is shown, provided that the bird represents a hydrogen atom or an alkyl group, and the bird represents an alkyl group. Examples of different alkyl groups include methyl group, ethyl group, and n-tabil group.

n-butyl group, fl-amyl group, n-hexyl group.

An n-octyl group is preferred. Birds and birds are substituted or unsubstituted alkyl groups (e.g., methyl, ethyl, propyl, butyl, aeryl groups, 2-chloro is ethyl, 2-methoxyethyl, 2-ethoxyethyl) ,
2-Hydroxyethyl group, 3-trinitropyr group, 3-
methoxypropyl group, 3-ethoxypropyl group, 3-hydroxypropyl group, 4-methoxy, butyl group, 4-ethoxybutyl group, 4-hydroxybutyl group, etc.), substituted or unsubstituted atruki # group (e.g. , tb, benzyl group, 7enethyl group, clotetrabenzyl group, dichlorobenzyl group, triclotetrabenzyl group, methoxybe/zyl group, acetylbe/zyl group, α-su7tylmethyl group, β-su7tylmethyl group, etc.) or a substituted or unsubstituted aryl group (e.g., phenyl group, tolyl group, xylyl group, biphenyl group, chlorophenyl group, di-a-phenyl group, hydroxy-7enyl group, -cyanophenyl group, me)-? diphenyl group.

(dimethoxyphenyl group, α-su7tyl group, β-naphthyl group, etc.).

X represents an atomic group necessary to complete an aromatic hydrocarbon ring or a heterocycle, and these rings include a chlorine atom, a bromine atom,
Halogen atoms such as iodine atoms, alkyl groups such as methyl groups, ethyl groups, propyl groups, butyl groups, amyl groups, 2-
Hydroxyethyl group, 2-methoxyethyl group, 2-ethoxyethyl group, 2-chloroethyl group, 3-hydroxynorobyl group, 3-methoxypropyl group.

3-ethoxypropyl group, 4-hydroxybutyl group, 4
- Substituted alkyl groups such as methoxybutyl groups, alkoxy groups such as ethoxy groups, pipoxy groups, butoxy groups, acetyl groups, pionyl groups, butyryl groups,
It can be substituted with an acyl group such as a benzoyl group or a trioyl group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and examples of the heterocycle include an indole ring, a benzofuran ring, and a carbazole ring.

R, , &, & and turtle are hydrogen atoms, hydrogen atoms (
For example, chlorine atom, bromine atom, iodine atom) or 1
Indicates the organic residue of valence. Examples of monovalent organic residues include alkyl groups such as methyl group, ethyl group, tetravir group, butyl group, and aryl group.

Examples include alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy groups, O-acetyl groups such as acetyl, tetrapionyl, and butyryl groups, nido radicals, human tetrachloric groups, and cyano groups. can.

Representative examples of the bisazo pigment represented by the general formula (1) are:
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bisazo pigment to A (1) − Oh.

C! Ml csH,OH CiHsOCHs C,H,OCIHI CtHs (qHs) These bisazo pigments can be used alone or in combination of two or more.

The bisazo pigment represented by the general formula (1) has the general formula (In the formula, hawk, bird, bird and ya are synonyms as above.

) The diamine represented by is tetrazotized by a conventional method, and then the corresponding coupler is coupled in the presence of an alkali, or the tetrazonium salt of the diamine is converted into a borofluoride salt or a zinc chloride double salt. Once isolated, the I
IC can be manufactured.

Next, we will show a typical example of the bisazo pigment used in the present invention and its synthesis method.

Synthesis Example (Regarding the above-mentioned bisazo pigment 4(1)) λ5-bis(P-(P-aminostyryl)phenyl)
-1,3,4-oxadiazole 11.4 f(0,0
25 mol) of water 65-1 concentrated hydrochloric acid 13.24 fIIt (0
, 15 mol) & C111 Add 1 sodium nitrite to the dissolved solution and 3.
A solution prepared by dissolving 54F (0,051 mol) in 10.6 mm of water was added dropwise over 5 minutes while maintaining the liquid temperature at 4.5 to 7°C, and then stirred at the same temperature for 30 minutes.

Next, 10.57 t (0,0525 mol) of 3-hydroxy-naphthalene-2-cal 7-acid methylamide and 5f (0,42 mol) of caustic soda were added to 420 dK of water.
The above tetrazotized solution was added dropwise to the dissolved solution over 10 minutes while maintaining the solution temperature at 4 to 10°C, stirred at the same temperature for 2 hours, and then left overnight.

- After filtering, washing with water and drying, use methyl ethyl ketone to
．． Dried pigment IL8 after 0 hour soxhlet? (yield 72%).

Elemental analysis: O, Toki, N5os Calculated value (in) Experimental value (π) 0 7 3, 6 4 73.6
9H4,544-51 N 1 2.7 3 1 2.7
5. Other bisazo pigments that can be used in the present invention can also be synthesized in exactly the same manner. A layer in which pigment is dispersed in a binder is provided on top of the layer.

■ Pigment in a charge transporting medium consisting of a charge transporting material or the material and an insulating binder (the binder itself may be a charge transporting material) as disclosed in Japanese Patent Publication No. 47-18545 and Japanese Patent Application Laid-Open No. 47-30328. Dispersed layer is provided on a conductive layer.

■A conductive layer as disclosed in JP-A No. 49-105537,
Consisting of a charge generation layer and a charge transport layer containing organic pigments.

(2) Il# There are charge transfer complexes such as those disclosed in 1983-91648, in which a diluent is added to the charge transfer complex.

The electrophotographic photoreceptor of the present invention is characterized by containing a bisazo pigment represented by the general formula (1), and can be applied to any type of electrophotographic photoreceptor having such characteristics, but the general formula ( In order to increase the transport efficiency of charge carriers generated by light absorption of the bisazo pigment shown in 1), ■, ■.

It is desirable to use it as a type of photoreceptor. Furthermore, a photoreceptor of type 9 is most desirable in that it separates charge carrier generation and transport functions and takes advantage of the characteristics of the pigment.

Therefore, this type 2 electrophotographic photoreceptor will be explained in detail.

As for the layer structure, a conductive layer, a charge generation layer 1, and a charge transport layer are essential, and the charge generation layer may be either above or below the charge transport layer, but in an electrophotographic photoreceptor of the type that is used repeatedly. If necessary, an adhesive layer may be provided for the purpose of improving adhesion with the conductive layer, charge generation layer, and charge transport layer mainly from the viewpoint of physical strength, and in some cases from the viewpoint of chargeability.

As the conductive layer, a metal plate or metal foil such as aluminum,
A plastic film or aluminum foil laminated with paper on which a metal such as aluminum is vapor-deposited, or paper that has been subjected to conductive treatment is used.

Effective materials for the adhesive layer include resins such as casein, polyvinyl alcohol, water-soluble ethylene-acrylic acid copolymer, and nitrocellulose. The thickness of the adhesive layer is 0.1~
5μ, preferably Q, 5-3μ is suitable.

The general formula (1
) The bisazo pigment shown in ) can be made into fine particles, and then it can be prepared without a binder or, if necessary, by dispersing it in a suitable binder solution, and applying and drying the solution.

When dispersing the bisazo pigment, known methods such as ball milling and attritor can be used, and it is desirable that the pigment particles have a diameter of 5 microns or less, preferably 2 seconds or less, and optimally 0.5 tones or less.

The bisazo pigment can also be applied by dissolving it in an amine solvent such as ethylenediamine.

-* For the method on the right, conventional methods such as blade, Mayer bar, spray, and dipping are used.

The thickness of the charge generation layer is Ss or less, preferably 0,01-
Desirably, IJ is %fh, and when a binder is used in the charge generation layer, a large amount of binder affects sensitivity, so the ratio #i of the binder in the charge generation layer is desirably 80 or less, preferably 40X or less.

The binder used is polyvinyl butyral,
Polyvinyl acetate, polyester, polycarbonate, phenoxy resin, acrylic resin, polyacrylamide,
Various resins such as polyamide, polyvinylpyridine resin, cellulose resin, phletane resin, epoxy resin, casein, and polyvinyl alcohol are used.

A charge transport layer can be deposited on the charge generation layer provided in this manner. If the charge transport material does not have film-forming ability, a method can be used in which a solution prepared by dissolving a binder in a suitable solvent is applied and dried by a conventional method to form a charge transport layer.

Examples of charge transporting substances include electron transporting substances and hole transporting substances; examples of electron transporting substances include chloranil, furoanil, tetracyanoethylene, tetracyanomethane, and 2,4.7-dolinito-9-fluorenone. , 2.4. to 7-tetranitro-9-fluorenone, 2
,4.7-dolinitro9-dicyanomethylenefluoreno/,2,4.5.7-titranitroxanthone,2,
There are electron-withdrawing substances such as 7 tons of 4.8-trinitrothioxa, and polymerization of these electron-withdrawing substances.

Examples of hole-transporting substances include pyrene, N-ethylcarbazole, N-isopropylcarbazole, N-)thyl-N
-phenylhydrazino-3-fif”) f-9-ethylcarbazole, N,N-diphenylhydrazino-3-
Methylidene-9-ethylcarbazole, N,N-diphenylhydrazino-3-methylidene-1O-ethylphenothiazine, N,N-diphenylhydrazino-3-methylidene-1O-ethylphenoxazine, P-diethylaminobenzaldehyde- N,N-diphenylhydrazone, P-diethylaminobenzaldehyde-N-α-su7
Chi-N-phenylhydrazone, P-bisu dinobenzaldehyde-N, N-diphenyl and dracin, 1.3
．． 3-) Limethylindolenine-〇-aldehyde-N
, N-diphenylhydrazone, hydrazones such as P-diethylbenzaldehyde-3-methylbenzthiazolinone-2-hydrazone, 2,5-bis(P-diethylaminophenyl)-1,3,4-oxadiazole, l −
7enyl-3-(P-diethylaminostyryl)-5-
(P-diethylaminophenyl)pyrazoline, 1-(quinolyl7 (2)) -3-(P-/'”7“7
</2+lJ")-5-(P-diethylamino7enyl)pyrazoline, 1-(pyridyl(2))-3-(P
-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-(6-medoxypyridyl(2))-3-(P-diethylaminostyryl)
-5-(P-diethylaminophenyl)pyrazoline, 1
-[Pyridyl(3)] -3-(P-diethylaminostyryl)-s-(p-diethylaminophenyl)pyrazoline, 1-[Levidyl(2)), -3-(P-
diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline, 1-(pyridyl(2))-
3-(P-diethylaminostyryl)-4-methyl-5
-(P-diethylaminophenyl)pyrazoline, 1-[
Pyridyl (21) -3-<α-methyl-P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoly/, 1-phenyl-3-(P-diethylaminostyryl)-4-methyl-5-(P -1>ethylaminophenyl)pyrazoline, l-phenyl-3-(α-benzyl-P-diethylaminostyryl)-5-(P-diethylamino7enyl)pyrazoline, spiropyrazoline and other pyrazolines, 2-(P- diethylaminostyryl)-6-ethylaminobenzoquinazole, 2-(
Oxazole compounds such as P-diethylaminophenyl)-4-(P-dimethylaminophenyl)-5-(2-riprophenyl)oxazole, 2-(P-diethylaminostyryl)-6-ethylaminobenzothiazole, etc. Thiazole compound, bis(4-diethylamino-
Triarylmethane compounds such as 2-methylphenyl)-phenylmethane, 1. l-bis(4-N,N-diethylamino-2-methylphenyl)hegtan%1. l, 2
．． 2-tetrakis(4-N,N-dimethylamino-2-
Polyaryl alkali 792 such as methylphenyl)ethane
4% triphenylamine, poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene,
Examples include polyvinyl acridine, poly-9-vinylphenylanthracene, helene formaldehyde resin, and ethyl carbazole formaldehyde flank. The charge transport materials are not limited to those described herein, and problems may arise when using one charge transport material or a mixture of two or more charge transport materials.

The thickness of the charge transport layer is 5 to 30μ, preferably 8 to 20μ.
It is.

As the binder, acrylic resin, polystyrene, polyester, polycarbonate, etc. can be used. As the binder for the low-molecular hole-transporting substance, the aforementioned hole-transporting polymer such as poly-N-vinylcarbazole can be used as the binder. On the other hand, U8P4122113 is used as a binder for low-molecular electron-transporting substances.
A polymer of the electron transporting substance V- as shown in can be used.

When using a photoreceptor in which a conductive layer, a charge generation layer, and a charge transport layer are laminated in this order, and the charge transport material is an electron transport material, the surface of the charge transport layer must be positively charged. Band 4 When exposed to light, electrons generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface and neutralize the positive charge, causing a decrease in surface potential between the U and unexposed areas. Electrostatic contrast occurs.

A visible image can be obtained by developing the electrostatic latent image thus formed with a charged, electrically conductive toner. This can be directly fixed, or the toner image can be transferred to paper, plastic film, etc. and then developed and fixed.

Alternatively, a method may be used in which the electrostatic latent image on the photoreceptor is transferred onto an insulating layer of transfer paper, then developed and fixed. The type of developer, the developing method, and the fixing method may be any known ones or known methods, and are not limited to specific ones.

On the other hand, when the charge transport material consists of a hole transport material, the surface of the charge transport layer must be negatively charged, and when exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area. , then reaches the surface and transfers the negative charge to +a
However, the surface potential attenuates and electrostatic contrast occurs between the surface potential and the unexposed area. During development, it is necessary to use a positively charged toner, contrary to the case where an electron transport material is used.

The ■ type photoreceptor is made by adding a bisazo pigment represented by the general formula (1) to an insulating binder solution, such as that used for the charge transport layer of the type ■ photoreceptor, and coating and drying it on a conductive support with a dispersion diameter. can get.

The ■ type photoreceptor is made by dissolving the charge transport material and the insulating binder used for the charge transport layer of the ■ type photoreceptor in an appropriate solvent, and then adding the bisazo pigment represented by the general formula (1). After dispersion, it is obtained by coating and drying on a conductive support.

■-Eve's photoreceptor forms a charge transfer complex when the electron transport material and hole transport material described in the ■ type photoreceptor are combined, so a charge transfer complex is added to the solution of the charge transfer complex as shown by the general formula (1). A bisazo pigment is added thereto, and after dispersion, it is coated on a conductive support and dried.

In any photoreceptor, the pigment used is of the general formula (1)
A photoreceptor containing at least one type of pigment selected from the bisazo pigments shown in the following, and using a combination of pigments with different light absorptions as necessary.The purpose is to increase the sensitivity of the photoreceptor and obtain a panchromatic photoreceptor. It is also possible to use a combination of two or more types of bisazo pigments represented by the general formula m, or in combination with a charge generating material selected from known dyes and pigments.

The electrophotographic photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in a wide range of electrophotographic applications such as laser printers and CRT printers.

Next, the present invention will be explained according to examples.

Example 1 A polyvinyl alcohol aqueous solution was applied onto an aluminum plate having a thickness of 100 μm and dried to form an adhesive layer with a coating rate of 8 s'/m'.

Next, polyester resin (polyester adhesive 4
9,000 - 1/20 solids; manufactured by DuPont, USA) 10
Disperse 5t of bisazo pigment of the above-mentioned pigment 4(1) in a solution of F dissolved in tetrahydro 7ran 80-, apply this dispersion on the adhesive layer, and measure the coating amount after drying. 0.
209/n? A charge generation layer was formed.

Next, hydrazone compound 5f of the structural formula and polymethyl methacrylate resin (number average molecular weight 10,000) 5f1 were mixed with benzene 70 + dK.
Dissolve and coat on the charge generation layer, and after drying, the coating amount is 1
Of/*/ A closed charge transport layer was formed.

The electrophotographic photoreceptor thus prepared was statically charged with corona at 05 KV using Kawaguchi Electric Co., Ltd.'s Seiden Copying Paper Tester Model 5P-428, held in a dark place for 10 seconds, and then charged at an illuminance of 5/ux. It was exposed to light and its charging characteristics were investigated.

The initial potential is Vo (V), the solder level retention rate for 10 seconds in the dark is Rv (X), and the half-attenuation exposure amount is E% (tux-sec
), the charging characteristics of each photoreceptor were investigated, and the results are shown in Table IK.
show.

Table 1 Vo: -570 Port Rv: 92% 8%: 5.01ux*sec Example 2 On top of the charge generation j- created in Example 1, a 2.4°7-
) IJ nitro-9-fluorenone 5t and poly-4,
The coating amount after drying the 4'-dioxydiphenyl-2,2'-propane liquid is 109/11? It was applied and dried.

The band '11llc measurement of the '1 child photosensitive element thus prepared was carried out in the same manner as in Example 1. At this time, the charging polarity was set to ■. The results are shown in Table 2.

Table 2 Vo: +4'IO Voltre: 89X Fa! A: 11.1 /ux -sec Example 3~
22 Apply a volibimol alcohol aqueous solution on the aluminum surface of the aluminum vapor-deposited mylar film and dry it, coating amount 1.2 f/W? An adhesive layer was formed.

Next, 5 tons of each bisazo pigment shown in Table 3 below and 2 tons of butyral resin (degree of butyralization 63 mol%) were mixed with 9 liters of ethanol.
After dispersing with the solution dissolved in 5-, it was applied to the aluminum surface of the aluminum vapor-deposited mylar film, and the coating amount after drying was 0.
．． 2t/lv? A charge generation layer was formed.

Next, Kl-(quinolino-(21)-3-(P-diethylaminostyryl)-5-(P-diethylaminophenyl)pyrazoline 5F, a solution obtained by dissolving the polycarbonate resin 5F used in Example 2 in 7011 g of tetrahydrofuran, was used to generate the above charge. The charge transport layer was coated on the layer and dried to form a charge transport layer having a coating weight of lxt/-.

The charging of the photoreceptor thus prepared was measured in the same manner as in Example 1, and the results are shown in Table 3.

'& 3 Example 23 An ammonia aqueous solution of casein was applied and dried on an Al-Z board with a thickness of 100 μm to form an adhesive layer with a coating weight of 1.0 f/j.

&ni2-(P-siethylatanophenyl)-4-(P-
dimethylaminophenyl)-5-(2-chlorophenyl)oxazole 5f and poly-N-vinylcarbazole 5
t (number average molecular weight 300,000) to tetrahydrofuran 70d
[Pigment scraps (1) are added to the dissolved liquid. After adding Of and dispersing it, it was applied and dried on the adhesive layer, and the coating amount was 11 f/-
And so.

The photoreceptor thus prepared was subjected to charge measurement in the same manner as in Example 1, and the measured values were as follows. However, the charging polarity was set to e. The results are shown in Table 4.

Table 4 Vo: +520 volts Rv: 88 copies 8%: Lo, 7/ux-sec

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor comprising a layer containing at least one bisazo pigment represented by the following general formula (1). General formula (1) is shown. However, bird represents a hydrogen atom or an alkyl group, and - represents an alkyl group. The words "salted" and "melon" indicate a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted aryl group. X represents a substituted or unsubstituted aromatic hydrocarbon ring; and X represents an atomic group necessary to complete a substituted or unsubstituted heterocycle. R, ``R'' and ``R'' represent a hydrogen atom, a hydrogen atom, or an organic residue. )