JPH0331853A - Electrophotographic sensitive body - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Field of Application in the CII Industry] The present invention relates to an electrophotographic photoreceptor, and more specifically,
The present invention relates to an electrophotographic photoreceptor having a photosensitive layer containing a 7-layer compound having a natural coupler component.

[Prior Art] Conventionally, as electrophotographic photoreceptors using inorganic photoconductive substances, those using selenium, cadmium sulfide, zinc oxide, etc. are widely known.

On the other hand, electrophotographic photoreceptors using organic photoconductive substances include photoconductive polymers typified by poly-N-vinylcarbazole and 2,5-bis(P-diethylaminophenyl)-1,3,4- Those using low-molecular organic photoconductive substances such as xadiazole, and those in which such organic photoconductive substances are combined with various dyes and pigments are known.

An electrophotographic photoreceptor using an organic photoconductive substance has the advantage that it has good film-forming properties, can be produced by coating, has extremely high productivity, and can provide an inexpensive electrophotographic photoreceptor. Furthermore, it has the advantage of being able to freely control color sensitivity by selecting the sensitizers used, such as dyes and pigments, and has been extensively studied. Especially recently,
The development of a functionally separated photoreceptor in which an organic photoconductive pigment is used as a charge generation layer and a charge transport layer made of the above-mentioned photoconductive polymer or low-molecular organic conductive substance is laminated has made it possible to replace conventional organic electrophotographic photoreceptors. Significant improvements have been made in sensitivity and durability, which were considered to be disadvantages.

Many pigments have been proposed for use in such organic electrophotographic photoreceptors, but azo pigments in particular have been widely studied because pigments with various properties can be synthesized by combining an azo component and a coupler component. However, there are problems with sensitivity and potential stability during repeated use, and only a few materials are in practical use.

Coupler components used in such azo pigments include naphthol As-based couplers described in JP-A No. 47-37543, benzcarbazole-based couplers described in JP-A-58-122967, etc.; Naphthalimide couplers described in JP-A No. 54-79632, perinone couplers described in JP-A-57-176055, and the like are already known.

[Problems to be Solved by the Invention] An object of the present invention is to provide a novel electrophotographic photoreceptor having practical high sensitivity and stable potential characteristics during repeated use.

[Means for Solving the Problems, Effects] The present invention provides an electrophotographic photoreceptor having a photosensitive layer containing an azo pigment on a conductive support, in which the azo pigment has the general formula (
It is composed of an electrophotographic photoreceptor characterized by being an azo pigment having the structure shown in 1).

In the formula, Ar represents an aromatic hydrocarbon ring or a heterocycle which may have a substituent which may be bonded via a bonding group,
X represents an organic residue necessary for condensing with a benzene ring to form an aromatic hydrocarbon ring or a heterocycle which may have a substituent; R is an alkyl group which may have a substituent; It represents an aralkyl group, an aryl group or a heterocyclic group, Z represents an ugly atom or a sulfur atom, m is an integer of 0.1 or 2, and n is an integer of 1, 2.3 or 4.

More specifically, examples of the aromatic hydrocarbon ring and heterocycle which may have a substituent which may be bonded via an Ar bonding group include benzene, naphthalene, and fluorene.

Aromatic hydrocarbon rings of phenanthrene, azothracene, pyrenato, furan, thiophene, pyridine indole,
Heterocycles such as benzothiazole, carbazole 7cridone, dibenzothiophene, benzoxazole, benzotriazole, oxadiazole, thiadiazole, etc., and those in which the above-mentioned aromatic rings are bonded directly or with an aromatic group or a non-aromatic group, e.g. Triphenylamine diphenylamine, N-methyldiphenylamine, biphenyl, terphenyl, binaphthyl, fluorenone, phenanthrenequinone, azotraquinone, benzheptrone, diphenylocosadiazole, phenylbenzoxazole, diphenylmethane, diphenylsulfone, diphenyl ether, benzophenone, stilbene, Examples include distyrylbenzene, tetraphenyl-P-phenylenediamine, tetraphenylbenzidine monopyridyldiphenylamine, and the like.

Substituents on the above rings include alkyl groups such as methyl, ethyl, propyl, and butyl; flukoxy groups such as methoxy and ethoxy; halogen atoms such as fluorine, chlorine, and bromine; and dialkyl such as dimethylamino and diethylamide 7. Examples include an amino group, a hydroxy group, a nitro group, a cyano group, and a halomethyl group.

X is a naphthalene term that is fused with a benzene ring and has a substituent and can also be C, a 7-thracene ring, a carbazole group,
Fragrances such as henzcarpazole ring, dibenzcarbazole ring, dibenzofuran term, benzonaphthofuran ring, fluorenone ring, diphenylene sulfide ring, etc.! ! shows the organic residues necessary to form a hydrocarbon ring or a heterocycle.

Furthermore, the substituents of -h organic residues include alkyl groups such as methyl, ethyl, propyl, and butyl, alkoxy groups such as methoxy, ethoxy, and propoxy, substituted amine groups such as dimethylamino and diethylamino, and fluorine atoms. , ill element atom, bromine II; (child halogen atom, halomethyl group such as trifluoromethyl, nitro group, cyano group, etc.).

In R, the alkyl group includes methyl, ethyl, propyl, etc., the aralkyl group includes benzyl, phenethyl, etc., the aryl group includes phenyl, diphenyl, naphthyl, azothryl, etc., and the heterocyclic group includes pyridyl, Examples include groups such as thienylfuryl, thiazolyl, carbazolyl, dibenzofuryl, benzimidazolyl, and benzothiazolyl.

Substituents for the above groups include alkyl groups such as methyl and ethylpropyl, flukoxy groups such as methoxy and ethoxy, fluorine atoms, and chlorine atoms.

Examples include halogen atoms such as bromine and iodine atoms, fulkylamino groups such as dimethylamino and diethylamino, phenylcarbamoyl groups, nitro groups, cyano groups, and halomethyl groups such as trifluoromethyl.

Typical specific examples of the azo pigment represented by the general formula (1) are listed below.

The description of the exemplary pigments is by specifically indicating the azo component and the coupler component in the basic form.

Basic 1p l At-N-H-Cp Exemplary Pigment (1-
1) C, Hr Exemplary Pigment (2-2) M Exemplary Pigment (1-2) CPI CF2: Cp: PIh Exemplary #l Rice (1-3) Exemplary Pigment (2-3) CP2 Same basic type 2 Cp, -N=N-Ar-N-CPa Exemplary Pigment (2-1) PL Cp2: Same as above Exemplary Class 4 (2-4) CPI, CF2: CPI CPU: Same as above Exemplary Face $4 (2-5) CPI, CF2: Exemplified pigment (2-6) as above CPI CF2: Exemplified pigment (2-7) as above A r: -@-CH-C)l-@-CPI CF2 2 Exemplified pigment (2-8) as above CPI, CF2 : Exemplified Pigment (2-9) cpt CF2: Same as above Exemplified Pigment (2-10) Exemplified Pigment (2-14) CPI CF2: Same as above Exemplified Pigment (2-15) cpt.

CF2 2 Same as above exemplified pigment (2-16) CPI CF2 2 Same as above exemplified pigment (2-17) zHt CPI CF2 : Same as above exemplified pigment (2-11) A r : +N+ CPI CF2 2 Same as above exemplified pigment (2-12) cpt, CF2: Exemplified Pigment (2-13) CPl, CF2: Cp-CF2 2 Same as above Exemplified Pigment (2-18) CPI, CF2: Exemplified Pigment (2-19) cpt CF2: Same as above Exemplified Pigment (2-20) cpt CF2 2 Exemplary pigment (2-21) arc-@Basho (奸CPI 2: Same as above basic type 3 Cpney NlN-Ar-to N-CP3 HmN-Cpx Exemplary pigment (3-1) CPI, CR2 CF2.CR2 pt CR2 CR3 Exemplary Pigment (3-2) CPI, CR2, CF2: Same as above Exemplary Pigment (4-1) The azo pigment represented by the general formula (1) is obtained by diazotizing the corresponding amine by a conventional method, and then diazotizing it with a coupler in the presence of an alkali in an aqueous system. Coupling or converting the diazonium salt into a borofluoride salt or zinc chloride double salt in an organic solvent such as 7% N,N-dimethylformamide or dimethyl sulfoxide.
It can be easily synthesized by coupling with a coupler in the presence of a base such as sodium acetate, triethylamine, or triethanolamine.

Synthesis example (synthesis of example $4 (2-1)) 150 m of water in a 300 m beaker, 20 m of concentrated hydrochloric acid (0.23 mol)
Cool to 0°C, and add 4.0 ml of sodium nitrite to it.
A solution prepared by dissolving 6 g (0,067 mol) in 10 ml of water was dropped into the solution over 10 minutes while keeping the temperature of the solution below 5°C. After stirring for 15 minutes, carbon filtration was performed to obtain a tetrazotized liquid. In this liquid, 10.5 g of sodium borofluoride (0,
A solution of 096 mol) dissolved in 90 m of water was added dropwise, and the precipitated borofluoride i11 was collected by filtration, washed with cold water, washed with acetonitrile, and dried under reduced pressure at room temperature.

Yield 9.70g, yield 79.77% Next, put DMF 500m in a beaker.

After cooling the temperature to 5°C, the previously obtained borofluoride 1117.
Dissolve 60 g (o, 20 moles) and then door!
5.1 g (0,050 mol) of ethylamine was added dropwise over 5 minutes. After stirring for 2 hours, the precipitated pigment was collected by filtration and D
After washing 4 times with MF and 3 times with water, it was freeze-dried.

Yield: 15.30g, Yield: 79.85% Melting point: 300℃ or higher .92 1'i'Ii T-Photographic photoreceptor has 41 photosensitive layers containing azo 1 represented by the general formula (1) on a conductive support.
do.

The shape of the photosensitive layer may be any known shape i! It does not matter if i is taken, but in general formula (1), a photosensitive layer containing a small azo face $1 is used as a charge generation layer, and a charge transport layer containing a charge transport substance is added to this as a JA layer for functional separation. A type photosensitive layer is particularly preferred.

The 7It charge generation layer can be formed by applying a coating solution in which an azo pigment represented by the general formula (1) is dispersed together with a binder resin in a suitable solvent to a conductive support by a known method. It is desirable that the film thickness is, for example, 5 gm or less, preferably 0.1 to 1 gm.

The binder resin 4 used at this time is selected from a wide range of insulating resins and organic photoconductive polymers.
Preferred are polyvinyl butyral, polyvinyl Henzal, polyarylate, polycarbonate polyester, phenoxy resin, cellulose resin, acrylic resin, polyurethane, and the like. The amount used is the content in the charge generation layer - (
i is 80g1% by weight or less, preferably 40% by weight or less.

The solvent used is preferably selected from those that dissolve the resin described above but do not dissolve the charge transport layer or undercoat layer described later.

Specifically, ethers such as tetrahydrofuran and 1,4-dioxane, and cyclohexanone.

Ketones such as methyl ethyl ketone, amide compounds such as N,N-dimethylformamide, esters such as methyl acetate and ethyl acetate, and aromatic compounds such as toluene, xylene, and chlorobenzene.

Methanol, ethanol, 2-pronog)-lunato alcohols, chloroform, methylene chloride.

Examples include aliphatic/X-logenated hydrocarbons such as dichloroethylene, carbon tetrachloride, and trichlorethylene.

The charge transport layer is layered 1:1 on or below the charge generation layer,
``Receives charge carriers from the charge generation layer in the presence of m-field,
It has the function of transporting this.

The charge transport layer is formed by dissolving a charge transport material in a solvent together with an appropriate binder resin as necessary and coating the layer, and the film thickness is generally 5 to 40 gm.
5 to 30 JLm is preferred.

Charge transporting substances include electron transporting substances and hole transporting substances, and examples of electron transporting substances include 2,4,7-)linitrofluorenone, 2,4,5,7-titranitrofluorenone, and chloranil.

Examples include electron-withdrawing substances such as tetracyanoquinodimethane and polymerized materials of these electron-withdrawing substances.

Hole-transporting substances include polycyclic aromatic compounds such as pyrene and azothracene, carbazole-based, indole-based, imidazole-based, oxazole-based, thiazole-based, oxadiazole-based, pyrazole-pyrazoline-based, thiadiazole-based, triazole-based compounds, etc. heterocyclic compound, P-
Hydrazone-based compounds such as diethylaminobenzaldehyde-N,N-diphenylhydrazone, N,N-diphenylhydrazino-3-methylidene-9-ethylcarbazole, α-2enyl-4'-N,N-diphenylaminostilbene, 5-[ 4-(di-p-tolylamino)benzylidene] -3H-dibenzo[a, d] A styryl compound such as cycloheptene, a benzidine compound, a triarylmethane compound, triphenylamine, or a group consisting of these compounds. polymers in the chain or side chains, such as poly N-vinylcarno(sol).

polyvinylazotracene, etc.).

In addition to these transport materials, inorganic materials such as selenium, selenium-tellurium, amorphous silicon, and cadmium sulfide can also be used.

Further, these charge transport materials can be used alone or in combination of two or more.

When the charge transport material does not have film-forming properties, a suitable binder can be used. Specifically, insulating resins such as acrylic resin, polyarylate, polyester, polycarbonate, polystyrene, acrylonitrile-styrene copolymer, polyacrylamide, polyamide, chlorinated rubber, or organic resins such as poly-N-vinylcarbasol and polyvinylazothracene are used. Examples include photoconductive polymers.

Examples of the conductive support on which the photosensitive layer is formed include If
7 Jl/E nium 4 aluminum alloy, copper, zinc stainless titanium, nickel, indium, gold, platinum, etc. can be used.

In addition, plastics (e.g. polyethylene,
Polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, etc.) or conductive particles (e.g. carbon black, silver particles, etc.) are coated on a plastic or metal support with a suitable binder resin, or conductive particles are coated on a plastic or metal support. A support such as paper impregnated can be used.

41 Barrier function and contact RF between the transparent support and the photosensitive layer
A functional F-pulling layer can also be provided.

The drag layer can be formed of casein, polyvinyl alcohol nitrocellulose, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, flucogin methylated nylon, etc.), polycareta, aluminum fluoride, and the like.

The thickness of the pull layer is 5 pm or less, preferably 0.1 to 3 μm.
is appropriate.

Another specific example of undeveloped IJI is an electron photoreceptor in which the ano-pigment represented by the general formula (1) and a charge transport substance are contained in the same layer. In this case, as the electrotransporting substance, an electrolytic 6;1-transfer vJ55 substance such as poly N-vinylcarpazole and trinitro-2-fluorenone can also be used.

The electron η′ true photoreceptor in this example is represented by the general formula (]):
It can be formed by coating and drying a solution obtained by dissolving Nokaomoto 1 and an electrotransport material in a suitable resin solution.

General formula (1) used in any electrophotographic photoreceptor
) The crystalline form of the azo pigment represented by formula (1) may be amorphous or crystalline. It is also possible to use it in combination with silk or in combination with a known charge generating substance.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines but also for a wide range of electrophotographic IT applications such as laser beam printers, CRT printers, LED printers, liquid crystal printers, and laser plate making. .

[Example] Example 1-18 A solution prepared by dissolving 5 g of methoxymethylated nylon (average molecular weight 32,000) and 10 g of alcohol-soluble copolymerized nylon (average molecular weight 2 Jj 9,000) in 95 g of methanol on an aluminum support. Paint it with Meyerba, ,
A drag layer having a thickness of 1.0 μm after drying was provided.

Next, 5 g of exemplified pigment (2-1) was added to cyclobequinone 9
5rnQ with butyral resin (butyralization degree 63 mol%)
) was added to the solution in which 2 g of the solution had been dissolved, and the mixture was dispersed using a sand mill for 20 hours.

This fractional liquid was applied onto the previously formed undercoat layer using a Mayer bar so that the film thickness after drying was 0.2 pm, and dried to form a charge generation layer.

Next.

After holding it in a dark place for 1 second, it was exposed to an illuminance of 10 lux,
The charging characteristics were investigated.

The charging characteristics include the surface potential (Vo) and the amount of light exposure (E) required to attenuate the potential by half after leaving it in the dark for 1 second.
l/2) was measured.

Show the results.

5g of hydrazone compound and polymethyl methacrylate (
A charge transport layer was formed by dissolving 5 g of the number average molecular weight (10,000) in 40 ml of toluene, coating it on the charge generation layer using a Mayer bar so that the film thickness after drying was 20 pm, and drying it to form a charge transport layer. An electrophotographic photoreceptor of Example 1 was prepared.

Electrophotographic photoreceptors corresponding to Examples 2 to 20 were prepared in exactly the same manner using other exemplified pigments 1 in place of exemplified pigment (2-1).

Electrostatic copying paper test 4 of the electrophotographic photoreceptor prepared in this way! tI (Model 5p-428, Kawaguchi M!,
Corona charged at -3KV using a
(2-1) 2 (1-2) 3 (1-3) 4 (2-2) 5 (2-3) 6 (2-4) 7 (2-5) 8 (2-6) 9 (2 -7) to (2-12) 11 (2-1,3) 12 (2-14) 13 (2-15) 685 1 690 2 700 2 705 1 705 0 690 2 710 2 700 2 705 2 685 2 680 1 690 1 695 l 14 (2-16) 700 2.61
5 (2-17) 695 1.316
(2-18) 700 1.217
(2-19) 705 1.418
(2-20) 700 1.219 (
2-21) 695 1.920 (3
-1) 690 1.8 Comparative Examples 1 and 2 Electrophotographic photoreceptors were prepared in exactly the same manner as in Example 1, except that the pigment used in Example 1 was replaced with a pigment having the following structure.

Charging characteristics were evaluated in the same manner.

(Comparative example 1) (corresponds to Example 5) Comparative pigment Vo knee 700V El/2: 8.1jLuxssec (Comparative example 2) (corresponds to Example 11) Comparative pigment Vo knee 680V El/2: 9, 5Jluxs sec
Examples 21 to 23 Using the electrophotographic photoreceptors prepared in Examples 6, 12 and 16, fluctuations in bright area potential and dark area potential during &1 repeated use were measured.

As a method, the photoreceptor was attached to the cylinder of an electrophotographic copying machine equipped with a -6.5 KV corona charger, an exposure optical system, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner. This copying machine is configured to produce an image on transfer paper as the cylinder is driven.

Using this copier, the initial dark area potential (VD) and light area potential (VL) were set to around 700V and -200V, and the dark area potential (
Vo) and light area potential (VL) were measured. Show the results.

21 6 695
18022 12 70
0 18523 16
700 17021 6
685 19522 1
2 690 19523
16 685 185 Comparative Example 3
and 4 Regarding the electrophotographic photoreceptors used in Comparative Examples 1 and 2, potential fluctuations during use of edge-turning were measured in the same manner as in Example 21. Show the results.

4 2 600 2
90 From the above results, it can be seen that the electrophotographic photoreceptor of the present invention has an excellent property of having little potential fluctuation when used for edge reversing.

Example 24 A subbing layer of polyvinyl alcohol having a thickness of 0.5 gm was formed on the aluminum surface of an aluminum vapor-deposited polyethylene tere-2-talate film.

On top of this, the dispersion of the disazo pigment used in Example 2 was applied using a Mayer bar to a dry film thickness of 0.2 μm, and dried to form a charge generation layer.

Next, 5 g of a styryl compound shown by the following structural formula and 3
1 700 1904
2 690 18
520 00 5 g of polyarylate (condensation polymer of bisphenol A and terephthalic acid-inphthalic acid) was added to 40 g of tetrahydrofuran.
The film thickness after drying is 20 ml.
A charge transport layer was formed by coating and drying to give JLm.

The band handling properties and durability characteristics of the electrophotographic photoreceptor thus prepared were determined by 4+1 in the same manner as in Examples 1 and 21. Show the results.

Charging characteristics Vo knee 700V E 17'2: 2.2 QuxIIsec song 4. ′
! ΔVD: -10V ΔV L: 4-15 Note that ΔV represents the amount of change in the dark area, ΔVL represents the amount of change in the bright area, the negative sign represents a decrease in potential, and the iF symbol represents an increase in the position. represents.

Example 25 A ring E photographic photoreceptor was prepared in which the same charge generation layer and directional transport layer as in the 1tiP photoreceptor were coated in the reverse order in the same manner as in Example 20, and the photoreceptor was coated in the same manner as in Example 1. stomach;?
The characteristics of the tunnel were evaluated. The results are shown below, however, the band's axial properties were set to iE.

Vr) : +720 V El/2:3 9Qux fist sec Example 26 In fact, the -1- of the psychotropic generation layer created in Example 10 is 2°47
-Dolinitro 9-fluorenone 5g and poly-4,4゛-dioxydiphenyl-2,2-propane carbonate (molecules +, + 300,000) 5g and chlorobenzene 70ml
The solution dissolved in water was dried and smoked so that the thickness after drying was 15 μm.

The charging characteristics of the * and f photographic photoreceptors thus prepared were evaluated in the same manner as in Example 1. Show the results.

However, the charging polarity was positive.

VQ: +710V El/2: 5.2Quix sec Conducted @27 2.4.7-1 5g of linitro-9-fluorenone and poly-N-vinylcarhesol (number 41 homogeneous molecules 11.3 million)
Dissolve 5g in 70ml of tetrahydrofuran (・'σfuran)
A cargo transport rust compound was prepared.

The face of this charge transfer complex compound and the exemplary pigment (2-12) 4
1g of polyester (part name Pylon 6 Tonboi) -1
M) 5 g to 70 m of tetrahydrofuran 9. Add to the solution dissolved in water and disperse.

This dispersion was applied to the same undercoat layer as in Example 1 after drying. :! It was coated with 11 liters to a thickness of 16 pm and dried. The charging characteristics of the electrophotographic photoreceptor thus prepared were measured by the same chisel method as in Example 1.

IQ l,,ri1? The electrode P was iE. Show the results.

Vn: +685V E l, / 2: 4, 2, Q x 轡s
e c [Effect of the invention] Not yet released1. ! By using a specific azo pigment in the photosensitive layer, Li's electrophotographic photoreceptor improves the carrier generation efficiency and/or carrier transport efficiency inside the photosensitive layer, improving sensitivity and improving the sensitivity during repeated use. It has the remarkable effect of providing excellent potential stability.

Claims (1)

[Claims] 1. An electrophotographic photoreceptor having a photosensitive layer containing an azo pigment on a conductive support, characterized in that the azo pigment is an azo pigment having a structure represented by general formula (1). Electrophotographic photoreceptor. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (1) In the formula, Ar represents an aromatic hydrocarbon ring or a heterocycle which may have a substituent which may be bonded via a bonding group,
X represents an organic residue necessary for condensing with a benzene ring to form an aromatic hydrocarbon ring or a heterocycle which may have a substituent; R is an alkyl group which may have a substituent; It represents an aralkyl group, an aryl group or a heterocyclic group, Z represents an oxygen atom or a sulfur atom, m is an integer of 0, 1 or 2, and n is an integer of 1, 2, 3 or 4. 2. The electrophotographic photoreceptor according to claim 1, wherein the photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer containing an azo pigment represented by the general formula (1).