JPS6363047A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity, to reduce variances in sensitivity and acceptance potential even during repeated uses, and to enhance durability by forming a photosensitive layer containing a specified azo compound on a conductive substrate. CONSTITUTION:The electrophotographic sensitive body has on the conductive substrate the photosensitive layer containing one of the diazo compounds represented by the formula shown on the right in which R is H or the like; Ar is an aromatic hydrocarbon group optionally linked through a bonding group or the like; and n is an integer of 1-4. Since these azo compounds generate charge carriers in extremely high efficiency when they absorb light, they are suitable for the constituent of the charge generating layer of the laminate type photosensitive body. The charge generating layer is obtained by dissolving or dispersing the azo compound of the formula into a proper solvent alone or together with a binder polymer, and coating the conductive substrate with this obtained coating solution, and drying it.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photoreceptor for electrophotography. Specifically, the present invention relates to a highly sensitive electrophotographic photoreceptor having a photosensitive layer containing an organic photoconductive substance.

(Problems to be solved by conventional technology and invention) Conventionally,
Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors. In recent years, advances have been made in the use of organic photoconductive materials such as polyvinyl carbazole in the light emitting layer of electrophotographic photoreceptors, and some of them have been put into practical use. Organic photoconductive materials have advantages over inorganic materials, such as being lightweight, easy to form a film, easy to manufacture photoreceptors, and depending on the type, transparent photoreceptors can be manufactured. have Although they have many advantages, organic photoconductive materials have not been widely used in electrophotographic photoreceptors because they are inferior to inorganic materials in terms of sensitivity and durability.

(Means for Solving the Problems) Therefore, the present inventors conducted extensive research on organic photoconductive materials that provide electrophotographic photoreceptors with high sensitivity and durability, and as a result, found that a specific azo compound MU is preferred.
We have now arrived at the present invention.

That is, the gist of the present invention is to provide the following general formula (1) on a conductive support (wherein R represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted phenyl group, and Ar is a bonding group, It is characterized by having a photosensitive layer containing an azo compound represented by an optionally bonded aromatic hydrocarbon group or a heterocyclic group, and n represents the number of /, co, 3, or ≠. Exists in electrophotographic photoreceptors.

The present invention will be described in detail below.The azo compound contained in the photosensitive layer of the electrophotographic photoreceptor of the present invention is represented by the general formula (1).

In the general formula (1), Rh represents a hydrogen atom, an alkyl group, or a substituted or unsubstituted phenyl group. Examples of alkyl groups include ◇Ij: methyl group, ethyl group, n-propyl group, 1-propyl group, n-butyl group, 1-butyl group, n-
Examples include hexyl group. Substituents for phenyl groups include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc.
Rodan atom: methyl group, ethyl group, n-propyl group, 1
- Alkyl groups such as propyl group, n-butyl group, 1-butyl group, n-hexyl group; metquine group, ethoxy group, 10
Examples include alkoxy groups such as boxy and butoxy groups; hydroxy groups; nitro groups; cyano groups. Among them, an alkyl group, a nitro group, a halogen atom, particularly a methyl group, a nitro group, and a chlorine atom are preferable.

In the general formula (1), Ar represents an aromatic hydrocarbon group which may be bonded via a bonding group having a valence of / to ≠, and Ar represents a heterocyclic group.

Examples of aromatic hydrocarbon groups include phenyl group, naphthyl group, /-pyrenyl group, -2-7:/tolyl group, and! −
/valent group of monocyclic or condensed polycyclic aromatic hydrocarbon such as acenaphthynyl group; phenylene group, /, 3- or ha/, ≠
-naphthylene group, 2, B-anthraquinonylene group,
Examples include monovalent groups of monocyclic or condensed polycyclic aromatic hydrocarbons such as 7-fluorenylene group and pyrenylene group; and divalent groups such as biphenylene group. The aromatic hydrocarbon group which may be bonded via a bonding group has the general formula (wherein, Y is 10-1-E! +, -8-6-1-6
O-1-SO2-1-aO-1-CONH-1-C horse-
, -CH=CH-1 monovalent groups such as bisphenylene group, xantonylene group, fluorenonylene group; other trivalent groups derived from tripheninylamine, triphenylmethane, terphenylfluorene, etc. .

Also, 'P! Examples of the bare ring group include a valent group of a 9- to JO-membered ring such as a naphtoylenebenzimidazolyl group, a benzimidazolyl group, a benzoxacylyl group, a carbazolyl group, a benzozazolyl group, a quinolyl group: carbazolediyl covalent groups of multi-stranded rings such as glue, co-θ membered rings such as benzothiophenediyl group, dibenzothiophenediyl group, benzothiophene oxide diyl group; trivalent groups such as N-phenylcarbazoletriyldio, triphenylamine-triyl group Group; tetraphenylethylenetetryl 1, p
, p'-diphenylamino-stilbene-tetrayl group and the like.

When considering sensitivity and durability, phenyl group, naphthyl group, pyrenyl group, naphthylene group, anthraquinonylene group, biphenylene a, n formula (wherein, Y is 10-
1-s-1-0H2-1-ca=cH-1 bisphenylene group, naphthylenebenzimidazolyl group, particularly in the present invention, these aromatic hydrocarbon groups and heterocyclic groups have substituents. It's really good. Specifically, nitro group; cyano group: halogen atom such as chlorine atom or bromine atom;
Alkyl groups such as methyl group, ethyl group, n-propyl group, 1-butyl group; alkoxy groups such as methoxy group, ethoxy group, propoxy group; aryl groups such as phenyl group; arylamino groups such as phenylamino group; phenoxy Examples include aryloxy groups such as nistyryl groups, arylvinyl groups such as naphthylvinyl groups, and the like. Among these, a nitro group, a cyan group, a methyl group, a methoxy group, a chlorine atom, and particularly a nitro group and a cyan group are preferable.

The azo compound of the present invention has, for example, a coupler component represented by the following general formula (It) and a general formula Ar + NH! )
Coupling with a diazonium salt, tetrazonium salt, hexazonium salt or oxazonium salt derived from an aromatic mono-, di-, triode- or tetraamine represented by n (wherein Ar and n have the same meanings as above) It can be easily synthesized by reaction.

(It) (wherein, R has the same meaning as in the above general formula [!]) This coupling reaction is carried out according to a known method, and usually involves water and/or dimethyl sulfoxide, N,N-dimethylformamide, N - The reaction may be carried out in an organic solvent such as methylpyrrolidone at a reaction temperature of 30° C. or lower for 7 to 70 hours.

The coupler component represented by general formula (It) is, for example,
According to the following reaction formula (1), hydroxy-/,/-naphthalic anhydride (III) and carbamoylanilide (IV)
and by heating them without a solvent or in a solvent inert to the reaction, such as acetic acid, or by reacting them with a reaction accelerator such as p-toluenesulfonic acid or hydrochloric acid in some cases.

Specifically, the hydroxy-/,♂-naphthalic anhydride represented by the above formula (fil) includes cohydroxy-/,/-naphthalic anhydride, 3-hydroxy-/, /
-Naphthalic anhydride, derhydroxy/? - Naphthalic anhydride and the like. The azo compounds of the present invention are thus obtained, among which, in particular, 3-hydroxy-
/,/-Naphthalic anhydride is represented by the general formula (wherein, G represents a substituent such as a methyl group, a methoxy group, a nitro group, a hydroxyl group, a chlorine atom, etc., and m represents the number of O to Hiroshi. ) or a substituted product thereof; j
-bis(≠'-aminophenyl)-/, 3. An azo compound represented by the following general formula (■) obtained by a coupling reaction of ≠-oxadiazole with a tetrazonium salt is preferred.

(In the formula, G and m have the same meanings as in the above general formula (V).) The photosensitive layer containing the above azo compound can take various known forms, but the azo compound of the present invention , because it generates charge carriers with extremely high efficiency when it absorbs light.
Suitable as a heavy carrier generation material for a functionally separated photoreceptor that separates charge carrier generation and transfer functions, and is particularly suitable as a component of the charge generation layer of a laminated photoreceptor consisting of a charge generation layer and a charge transfer layer. ing.

The charge generation layer can be formed, for example, by coating a coating solution obtained by dissolving or dispersing the azo compound represented by the general formula (1) in an appropriate solvent or in a binder polymer on a conductive support. , obtained by drying.

Solvents for preparing the coating solution include basic solvents such as butylamine and ethylenediamine; ethers such as tetrahydrofuran, methyltetrahydrofuran, /,≠-dioxane, and diethylene glycol dimethyl ether; ketones such as methyl ethyl ketone and cyclohexanone; toluene, xylene, etc. Aromatic hydrocarbons; N,N-dimethylformamide, acetonitrile, N-methylpyrrolidone,
Examples include aprotic polar solvents such as dimethyl sulfoxide; methanol, ethanol, and ingropanol bamboo alcohols; esters such as ethyl acetate, methyl formate, and methyl cellosolve acetate; and chlorinated hydrocarbons such as dichloroethane and chloroform. These solvents can be used alone or in combination of two or more kinds. When using a binder polymer, it is desirable that the binder dissolves the polymer.

Binder polymers include styrene, vinyl acetate,
Polymers and copolymers of vinyl compounds such as acrylic acid esters and methacrylic fermentation esters; polyesters, polycarbonates, polysulfones, polyvinyl butyral,
Examples include phenoxy resin, cellulose ester, cellulose ether, urethane resin, and epoxy resin.

The amount of binder polymer used is usually 0.7 to 100% of the azo compound! The range is twice the weight.

Further, the azo compound is preferably present in the binder in the form of image particles of 7 μm or less.

The thickness of the charge generation layer is usually several μm or less, preferably 7 μm or less.

As the conductive support on which the charge generation layer is applied, any of those employed in well-known electrophotographic photoreceptors can be used. Examples of shellfish include metal drums and sheets made of aluminum, copper, etc., or laminates and vapor deposits of these metal foils; Plastic films, plastic drums, paper, paper tubes, etc. that have been coated with a conductive substance and a suitable binder to conductivity treatment can be used. Also included are plastic sheets and drums that contain electrically conductive substances such as metal powder-carbon black and carbon kasumi and are made electrically conductive.

The transfer vrh layer is formed on the self-charge generation layer by one process. Conversely, it is also possible to form five charge transfer layers on a π-saving support and laminate a burden generation layer on top of it, but since the burden generation layer is usually thin, it is difficult to prevent erosion and dirt. The former type is often used to protect the charge generation layer.

The charge transport layer is a layer that transports charge carriers (σ) generated in the charge generation layer, and contains a charge carrier transport medium. Heavy carrier transport media are generally classified into two types: electron transport media and hole transport media. However, both can be used in the photoreceptor of the present invention (b), and a mixture thereof can also be used. As the electron transfer U form, nitro group, cyano group, ester group, etc. Electron-withdrawing compounds having an electron-withdrawing group, such as nitrated fluorenone such as 2.t/-, 7-trinitrofluorenone, 2.≠,!, 7-tetranitrofluorenone, or tetracyanoquinodimethane. .

In addition, electron-donating organic photoconductive compounds can be used as hole transfer media, such as heterocyclic compounds such as carbazole, indole, imidazole, oxazole, thiazole, oxadiazole, pyrazole, biazoline, and thiadiazole, aniline derivatives, and hydrazine derivatives. , hydrazone, or polymers having a group consisting of these compounds in the main chain or side chain (polyvinylcarbazole, polyglycidylcarbazole), and the like.

Among these, the following general formula [■] YO (where R1 represents an alkyl group, @substituted alkyl group i and R2 represents an aralkyl group, an allyl group, a substituted alkyl group, a phenyl group, a naphthyl group, or (represents an aralkyl group, and zl represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom) (see JP-A-541-/jθ/2)
or the following general formula [■] (where XI, Y' and z2Vi represent a hydrogen atom, a lower alkyl group, a lower alkoxy group, a phenoxy group or an arylalkoxy7 group, and R3 is a hydrogen atom, a lower alkyl group, an allyl group) , phenyl group, naphthyl-1? or aralkyl group, m and t represent / or -, p represents 0 or /) are used alone or in combination. is preferable.

Charge transfer! ! r! J) When the charge carrier transfer medium is a low molecular weight compound, it forms a layer while being dissolved in the binder polymer. The charge carrier transport medium is used in an amount of vf to 0.0, co/, j, preferably 0.3 to 0.3 to 2, by weight, relative to the binder polymer.

As the binder polymer, a polymer similar to that used for the charge generation layer is used, and it is dissolved in a solvent together with the charge carrier transfer medium to form a housing liquid, and then applied.
Dry to form a T load transfer layer. The film height of the charge transport layer is 5 to 504 m, preferably 70 to 30 m.

Of course, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a known sensitizer. Suitable sensitizers include Lewis acids and dyes that form heavy transfer complexes with organic photoconductive materials. Examples of Lewis acids include chloranil,
Tips 3-dichloro/, Hiro-naphthoquinone, 2-methylanthraquinone, /-nitroanthraquinone, /-chloroOS-=)phanthraquinone 1. ! - quinones such as chloroanthraquinone, phenanthrenequinone,
≠-Aldehydes such as nitrobenzaldehyde, terbenzoylanthracene, indandione, 3. ! -Dinitrobenzophenone, j, J', ! ,j
'-Ketones such as tetranitrobenzophenone, acid anhydrides such as phthalic anhydride, Hiro-chloronaphthalic anhydride, tetracyanoethylene, terephthalalmalononitrile, Hiro-nitrobenzalmalononitrile s'' (p-nitropentyloxy ) Cyano compounds such as benzalmalononitrile; 3-benzalphthalide, 3-(α-cyano-p
-nitrobenzal) phtari)', j-(α-cyano-p
-Nitrobenzal)-ψ, j, include lightning-attracting compounds such as phthalides such as 7-tetrachlorophthalide. Examples of dyes include triphenylmethane dyes such as methyl violet, brilliant green, and crystal violet; thiazine dyes such as methylene blue;
Examples include quinone dyes such as quinizarin, cyanine dyes, pyrylium salts, thiapyrylium salts, and benzopyrylium salts.

Furthermore, the photosensitive layer of the electrophotographic photoreceptor of the present invention may contain a well-known plasticizer in order to improve film formability, recursivity, and mechanical strength. Examples of the plasticizer include aromatic compounds such as heptalic acid ester, phosphoric acid ester, epoxy compound, chlorinated paraffin, chlorinated fatty acid ester, and methylnaphthalene. In addition, if necessary, an adhesive layer,
Needless to say, it may include an intermediate layer and a transparent insulating layer.

(Effects of the Invention) The photoreceptor using the azo compound of the present invention has high sensitivity and good color sensitivity, and when used repeatedly, there is little variation in sensitivity and chargeability, and there is little optical fatigue. It has extremely high durability.

Furthermore, the photoreceptor of the present invention can be used not only in electrophotographic copying machines but also in laser, L
ED, OFT (0plcal Fiber Tub
Photoreceptors of printers that use e) etc. as light sources! It can also be widely used in the field of single-child photography.

(Examples) Next, the present invention will be explained in more detail using reference examples and examples, but the present invention is not limited to the following examples unless the gist thereof is exceeded.

Note that in the Examples and Examples e, "parts" indicates "parts by weight."

Reference example/ Compounds in Table-/, (Synthesis of Co) (1) 3-
Hydroxy-/? - Naphthalic anhydride (Tokyo Kasei Kogyo 34') ss, 6 parts and Hiro-aminobenzanilide q? 1 part was stirred in a mixed solvent of 50 parts of acetic acid and 2.0 parts of nitropenzea, and reacted for 2 hours at the boiling point of acetic acid.

After the reaction, the mixture was cooled to room temperature, and the precipitated crystals were thoroughly washed with methanol and then dried. The obtained crystals had a pale yellow color and did not melt at temperatures below 320°C. Elemental analysis and infrared absorption spectroscopy revealed that this crystal is 3-hydroxy-/,! -naphthalic acid (N-(ψ/
(N/-phenyl)benzoylamide)]imide. Yield Vi/7. The elemental analysis values for part J'' were as follows.

Total of 4 values as C25HI8041'h: C73, s3%, HJ, 9 flats, N, <,
, l'6% actual value: C73, 60%, HJ, (1 part 7
%, N 4. /J% (2) Said 3-hydroxy-/
,! -Naphthalic acid [N-[≠t (Nt-phenyl)
Add 3 parts of imide (benzoylamide) to this with 30 parts of dimethyl sulfoxide while pouring sideways at θ°C. f
-bis(Hiro'-aminophenyl) 'e3+Hiro-okhioxadiazole lazonium hydroborate dimethyl sulfoxide solution is added dropwise, followed by acetic acid)
Add the IJum aqueous solution dropwise and hold as it is for 3 hours. After the reaction, the precipitated bisazo compound is filtered, washed with methanol, dilute acetic acid, water, tetrahydrofuran, etc., and then dried. The obtained solid had a deep purple color and did not melt at temperatures below 3°C. Based on elemental analysis and infrared absorption spectrum (Figure 1) measurements, this compound was identified as the target bisazo compound. Collection t≠, /C64H3
Calculated price as II09NIO: C70, 4Lt Chi, HJ, Hirojichi, N/Co,
? ≠ Actual measurement value: C! 7 (7, ≠ Kochi, Hj, Hirojchi, N
/-0♂3chi Reference Example- (Table-/Synthesis of Compound A3) (
1) j-hydroxy-/,/-naphthalic anhydride (
(manufactured by Tokyo Kasei Kogyo Co., Ltd.) 10. ≠be and Hiro-amino-λ′
-Chlorobenzanilide/! , was dissolved in 50 parts of 0-dichloroben 4F, stirred, and 75 parts of p-toluenesulfonic acid/hydrate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added.
Next, react at 0°C for several hours. The product precipitated during the reaction was taken out hot, thoroughly washed with methanol, and then dried. The obtained crystals were pale yellow in color and did not melt at temperatures below 3-0°C. From elemental analysis values and infrared absorption spectrum measurements, this u A u J-hydroxy-/,? It was found to be -naphthalic acid [N-(≠/(N/, 2"-chlorophenyl)benzoylamide)]imide. The yield was 6./part, and the elemental analysis values were as follows.

C25H1sO4N2C1! Calculated values as: Ct 73.63%, HJ, Otsu/%, Nza,
23%, C1r, j't% actual value: C73,4M%,
H3, 62%, N Otsu Js%, C1r,! J'% (2) Using the above-mentioned anilide compound as the coupling component in Reference Example/, coupling was carried out with the same tetrazo component as in Reference Example/ to obtain a bisazo pigment in the same manner as in Reference Example/. The obtained solid had a deep purple color and did not melt at temperatures below 320°C. Elemental analysis and infrared absorption spectrum (second
Figure) Through measurements, this compound was identified as the target bisazo compound represented by the following structural formula.

C64H2S o, calculated value as NIOC4M Hat, 32%, HJ, /θchi, N/ko, 0tachi, Ct, O
Hirochi actual measurements: c, <g, coj%, HJ, 07chi, N/
2.07%, CtS, 7th Example/The azo compound Q, ≠j part shown in Table-/, synthesized according to the above reference example and the same reference example, was dispersed with 30 parts of cyclohexanone in a sand grinder, and the polyester (manufactured by Toyobo Co., Ltd., trademark Byron 200) was added and dissolved. The obtained dispersion of the azo compound was applied by DH onto a polyester film having a thickness of 0.00 pm, and then applied onto the aluminum vapor-deposited layer using a film applicator so that the dry film thickness reached 0.6 f/-, and then dried. .

20 parts of N-ethylcarbazole-3-aldehyde diphenyl crack 21 and 10 parts of methacrylic resin (manufactured by Mitsubishi Rayon Shisha Co., Ltd., trade mark: DIANAL BR-RS) were added to toluene, jj, and Q on the thus obtained layer. A charge transfer layer was formed by applying the solution dissolved in the sample to a dry film thickness of 10/Jm. In this way, an electrophotographic photoreceptor having a two-layer photosensitive layer was obtained.

The sensitivity of these photoreceptors is the half-life exposure (E IA)
The values are shown in Table-/, Table-Co, and Table-3.

The half-decrease exposure amount was measured using an electrostatic copying paper tester (model SP-≠ko♂ manufactured by Yoro Denki Seisakusho) using the photoreceptor. First, in a dark place, j was charged by corona discharge (■), and then exposed to white light with an illuminance of j 1ux, and the amount of exposure necessary for the surface potential to attenuate to half of the initial surface potential was determined.

[Brief explanation of the drawing]

FIGS. 1 and 2 are infrared absorption spectra of the bisazo compounds synthesized in Reference Examples C and 3, respectively. Applicant: San-ai Kasei Kogyo Co., Ltd. Agent: Patent attorney Yo Hase - and 7 others Figure 1 cm-' Figure 2 cM-/

Claims (1)

[Claims] (1) On the conductive support, the following general formula (I)▲mathematical formula,
There are chemical formulas, tables, etc. Indicates a good aromatic hydrocarbon group or heterocyclic group,
n represents a number of 1, 2, 3 or 4. ) A photoreceptor for electrophotography, comprising a photosensitive layer containing an azo compound represented by: