JPH05216256A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the electrophotographic sensitive body high in sensitivity and durability by using a specified hydrazone compound as a photoconductive substance. CONSTITUTION:The photosensitive layer formed on a conductive substrate contains the hydrazone compound represented by the formula in which each of A and B is aryl, aralkyl, 1-4 C alkyl, or a heterocyclic group; as R1, an electron donating group, such as methyl, ethyl, methoxy, or ethoxy is effective, and R3 is, preferably, p-tolyl, m-tolyl, 3,5-xylyl, p-methoxyphenyl, phenyl, or p-methoxybenzyl. This hydrazone compound is effectively used, especially, as a carrier transfer material in a functionally separated photosensitive body. The photosensitive body is formed by dissolving or dispersing the hydrazone compound together with a sensitizing dye, a chemical sensitizer, an electron attractive compound, and the like into a binder resin and coating a substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more specifically, it has the following general formula (I) in a photosensitive layer formed on a conductive support.

[Chemical 3] (In the formula, A and B are an aryl group which may have a substituent, an aralkyl group which may have a substituent, a heterocyclic group which may have a substituent, or an alkyl group having 1 to 4 carbon atoms, and R ¹
Is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and R ² may contain a hydrogen atom, an alkenyl group having 2 to 3 carbon atoms, or a substituent. It is a heterocyclic group, an alkyl group having 1 to 4 carbon atoms, or an aryl group which may have a substituent, and R ³ includes an aryl group which may have a substituent, an aralkyl group which may have a substituent, and a substituent. May be a heterocyclic group or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1,2,3. However, when n is 2 or 3, R ^1's may be the same or different, and may further form a methylenedioxy ring. The present invention relates to an electrophotographic photosensitive member containing a compound represented by the formula (1).

[0002]

2. Description of the Related Art Conventionally, in electrophotographic technology, inorganic substances such as selenium, cadmium sulfide, amorphous silicon and zinc oxide have been widely used in the photosensitive layer of electrophotographic photoreceptors. However, in recent years, much research has been conducted using an organic photoconductive material as an electrophotographic photoreceptor.

Here, the basic properties required for an electrophotographic photosensitive member are listed as follows: (1) the chargeability of corona discharge in a dark place is high, and (2) the obtained charge due to corona charge is dark. Where there is little attenuation, (3) charge is rapidly dissipated by light irradiation, (4) little residual charge after light irradiation, (5) increase in residual potential due to repeated use, initial potential (6) There is little change in electrophotographic characteristics due to temperature and humidity.

Although the conventional inorganic electrophotographic photoreceptors such as selenium and cadmium sulfide have the requirements as a photoreceptor in terms of basic properties, they are problematic in production, for example, have strong toxicity and film formability. Is difficult, there is not much plasticity,
It has drawbacks such as high manufacturing cost. Further, in the future, due to depletion of resources, it is desired to use a photoconductor made of an inorganic substance instead of an inorganic substance, which is limited in production, and in terms of pollution due to toxicity.

In view of these points, electrophotographic photoreceptors made of organic substances have been actively researched in recent years, and as a result, electrophotographic photoreceptors using various organic substances have been proposed and put into practical use. Some have.

Generally, organic materials have better transparency, lighter weight, and easier film formation than inorganic materials,
It has both positive and negative charging properties, and has the advantage that the photoconductor can be easily manufactured.

Typical examples of organic electrophotographic photoconductors that have been proposed so far include polyvinylcarbazole and dielectrics thereof, but these are not always film formability, plasticity, solubility, adhesiveness, etc. Not sufficient, and those sensitized with polyvinyl carbazole with a pyrylium salt dye (Japanese Patent Publication No. 48-25658) and those sensitized with polyvinyl carbazole and 2,4,7-trinitroflorenone (US Pat. No. 3,484,237). ), Etc., but those satisfying the basic properties required for the above-mentioned photoreceptor, mechanical strength, high durability, etc. have not been sufficiently obtained. Not not.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member having high sensitivity and high durability. In particular, the photoreceptor of the present invention is to provide a photoreceptor having excellent stability with respect to temperature and humidity, high charging characteristics, and almost no deterioration in photosensitivity even after repeated use.

The present inventors have studied the photoconductive material having the above-mentioned high sensitivity and high durability and found that the novel hydrazone compound represented by the following general formula (I) is effective. The present invention has been reached.

[0010]

[Chemical 4] (In the formula, A and B are an aryl group which may have a substituent, an aralkyl group which may have a substituent, a heterocyclic group which may have a substituent, or an alkyl group having 1 to 4 carbon atoms, and R ¹
Is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and R ² may contain a hydrogen atom, an alkenyl group having 2 to 3 carbon atoms, or a substituent. It is a heterocyclic group, an alkyl group having 1 to 4 carbon atoms, or an aryl group which may have a substituent, and R ³ includes an aryl group which may have a substituent, an aralkyl group which may have a substituent, and a substituent. May be a heterocyclic group or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1,2,3. However, when n is 2 or 3, R ^1's may be the same or different, and may further form a methylenedioxy ring. ) An electrophotographic photoreceptor containing the hydrazone compound of

The hydrazone compound of the general formula (I) according to the present invention is usually synthesized by the following synthetic method.

Various substituted benzaldehydes or various substituted phenyl ketone derivatives are reacted with N-phenyl-N-substituted hydrazine to obtain N-phenyl-N-substituted hydrazones (structural formula (III)).

[0013]

[Chemical 5] (Each symbol in the formula has the same meaning as in formula (I))

The N-phenyl-N-substituted hydrazone derivative represented by the structural formula (III) thus obtained is subjected to a formylation substitution reaction with phosphorus oxychloride and dimethylformamide or phenylmethylformamide to give a benzaldehyde derivative (formula). (IV)) is obtained.

[0015]

[Chemical 6] (In the formula, each symbol has the same meaning as in formula (I))

The benzaldehyde derivative thus obtained is a hydrazine reagent (formula (V)) containing various substituents.
The hydrazone compound (I) of the present invention can be obtained by reacting with

[0017]

[Chemical 7] (A and B have the same meaning as defined in formula (I))

In the general formula (I), the term "aryl group which may have a substituent" in the definition of A, B and R means an aryl group having 6 to 12 carbon atoms, for example, phenyl. , Or naphthyl. Examples of the substituent of the aryl group include an alkyl group having 1 to 2 carbon atoms such as methyl, ethyl, methoxy, or ethoxy, an alkoxy group, or a halogen atom such as chloro.

The heterocyclic group of "heterocyclic group which may have a substituent (s)" in the definitions of A and B is a 5- or 6-membered heterocyclic group containing a nitrogen atom and / or a sulfur atom, for example pyridyl. , Pyrrolyl, or thiazolyl. These heterocyclic groups may be fused with one or two benzene rings. Examples of the substituent of these heterocyclic groups include an alkyl group having 1 to 2 carbon atoms such as methyl or ethyl.

In the definitions of A, B, R ² and R ³ , "C1-C1
Examples of the “4 alkyl group” include methyl, ethyl, propyl, isopropyl, and butyl. R ¹
In the definition of, "alkyl group having 1 to 3 carbon atoms" means methyl,
Includes ethyl, propyl, or isopropyl.

The aralkyl of the "aralkyl group which may have a substituent (s)" in the definition of R ³ includes phenyl C _1-2 alkyl group such as benzyl. Substituents include those similar to those on the aryl group.

Specific examples of R ³ include methyl, ethyl,
Propyl, i-propyl, n-butyl, p-tolyl, m
-Tolyl, p-chlorophenyl, 3,5-xylyl, p
-Methoxyphenyl, p-ethoxyphenyl, phenyl, 1-naphthyl, 2-naphthyl, p-methoxybenzyl, p-methylbenzyl and benzyl. Of these, p-tolyl, m-tolyl, 3,5-xylyl, p-methoxyphenyl, phenyl, p-methylbenzyl and benzyl are preferred.

As R ¹ , substituents of an electron-donating group such as a methyl group, an ethyl group, a methoxy group, and an ethoxy group were more effective than an unsubstituted compound and an electron-withdrawing compound such as chlorine. Specific examples of A and B include phenyl, 1-naphthyl, p-tolyl, methyl, ethyl, benzyl, p-methylbenzyl, 1-pyridyl and the like. Especially A,
A compound in which any of B is a phenyl group and an electron-donating group-substituted phenyl group was effective.

Next, specific examples of the hydrazone compound of the present invention represented by the general formula (I) include those having the following structures.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

[Table 4]

[0029]

[Table 5]

[0030]

[Table 6]

[0031]

[Table 7]

Among these exemplified compounds, those which are excellent in electrophotographic properties and are excellent in terms of cost and synthesis are those in which R ¹ is hydrogen, p-methyl group or P-methoxy group, and R ² is Examples of the hydrazone compound include hydrogen, a methyl group, an ethyl group, R ³ is a phenyl group, a methyl group, an ethyl group, and A and B are a phenyl group, a p-tolyl group, and a methyl group.

The electrophotographic photosensitive member according to the present invention is obtained by containing one kind or two or more kinds of the compounds shown above, and as a result, it has extremely high performance.

Other hydrazone compounds (eg 4-
(Dibenzylamino) benzaldehyde-N, N-diphenylhydrazone, 4- (ethylphenylamino) benzaldehyde-N, N-diphenylhydrazone, 4-di (p-tolylamino) benzaldehyde-N, N-diphenylhydrazone, 3,3 -Bis- (4'-diethylaminophenyl) -acrolein-N, N-diphenylhydrazone), triphenylamine compound (for example, 4-
Methoxy-4 ′-(4-methoxystyryl) triphenylamine, 4-methoxy-4′-styryltriphenylamine) and the like can also be contained.

Various methods are conceivable as a mode of using these hydrazone compounds as an electrophotographic photoreceptor. For example, a photoconductor comprising a hydrazone compound and a sensitizing dye, and if necessary, a chemical sensitizer or an electron-withdrawing compound, dissolved or dispersed in a binder resin, is provided on a conductive support or A carrier provided mainly with a sensitizing dye or an azo pigment, a pigment represented by a phthalocyanine pigment, on a conductive support in the form of a laminated structure capable of forming a carrier generation layer having a high charge carrier generation efficiency and a carrier transport layer. If necessary, the hydrazone compound of the present invention on the generation layer, there is a laminated photoreceptor or the like, which is prepared by adding an antioxidant compound or an electron-withdrawing compound and dissolving or dispersing it in a binder to provide it as a carrier transport layer. It is possible to apply to both cases.

In making photoreceptors using the compounds of the present invention, the aid of a polymeric film forming binder on a support such as a metal drum, metal plate, electrically conductive processed paper, plastic film. Borrow and make a film. In this case, in order to further increase the sensitivity, it is desirable to add a sensitizer and a substance that imparts plasticity to the polymerizable film-forming binder as described below to form a uniform photoreceptor film.

As these polymerizable film forming binders, various ones can be mentioned depending on the field of use.

That is, in the field of photoconductors for copying machines or printers, polystyrene resins, polyvinyl acetal resins, polysulfone resins, polycarbonate resins, polyphenylene oxide resins, polyester resins, alkyd resins, polyarylate resins and the like are preferable. You may use these individually or in mixture of 2 or more types. Among these, resins such as polystyrene, polycarbonate, polyarylate, and polyphenylene oxide have a volume resistance value of 10 ¹³ Ω or more, and are also excellent in film forming property and potential property.

When the amount of these binders to be added to the hydrazone compound of the present invention is 0.2 to 20 times by weight, preferably 0.5 to 5 times, and 0.5 or less. However, there is a drawback that the hydrazone compound is deposited from the surface of the photoreceptor, and if it is more than 5 times, the sensitivity is remarkably lowered. An alkaline binder is especially required for use in printing plates. The alkaline binder is an acidic group soluble in water or an alcoholic alkaline solvent (including mixed system),
For example, it is a polymer substance having an acid anhydride group, a carboxyl group, a phenolic hydroxyl group, a sulfonic acid group, a sulfonamide group, or a sulfonimide group. It is preferable that these alkaline binders usually have a high acid value of 100 or more.

The binder resin having a large acid value is easily dissolved or easily swelled in an alkaline solvent. Examples of these binder resins include styrene: maleic anhydride copolymer, vinyl acetate: maleic anhydride copolymer, vinyl acetate: crotonic acid copolymer, methacrylic acid: methacrylic acid ester copolymer, phenol resin, methacrylic acid. Acid: styrene: methacrylic acid ester copolymer and the like. The ratio of these resins added to the photoconductive organic substance may be approximately the same as in the case of the photoconductor for a copying machine.

Next, as a sensitizing dye added to the photosensitive layer, triphenylmethane dyes represented by methyl violet, crystal violet, night blue, Victoria blue, etc., erythrosine, rhodamine B, rhodamine 3R, acridine orange. , Acridine dyes such as flapeosin, thiazine dyes such as methylene blue and methylene green, capri blue,
Oxazine dyes such as Meldola blue, other cyanine dyes, styryl dyes, pyrylium salt dyes,
There are thiopyrylium salt dyes. In the photosensitive layer, as photoconductive pigments that generate charge carriers with extremely high efficiency by light absorption, phthalocyanine-based pigments such as various metal phthalocyanines, metal-free phthalocyanines, halogenated metal-free phthalocyanines, perylene imides, and perylene anhydrides. Perylene pigments such as, bisazo pigments, azo pigments such as trisazo pigments, quinacridone pigments, and anthraquinone pigments.

Particularly, the pigments which generate charge carriers include metal-free phthalocyanine pigments, titanyl phthalocyanine pigments, fluorene and bisazo pigments containing a phlorenone ring, bisazo pigments composed of aromatic amines, and trisazo pigments, which give high sensitivity. Gives excellent electrophotographic photoreceptors.

The above-mentioned dyes may also be used as the charge carrier generating substance. These dyes may be used alone, but in many cases the coexistence of a pigment generates charge carriers with higher efficiency. In addition to the spectral sensitizers mentioned above, it becomes necessary to add various chemical substances for the purpose of preventing the increase of residual potential, the decrease of charging potential, the decrease of sensitivity, etc., due to repeated use. ..

As the substances to be added, 1-chloroanthraquinone, benzoquinone 2,3-dichloronaphthoquinone, naphthoquinone, 4,4'-dinitrobenzophenone, 4,4'-dichlorobenzophenone, 4-nitrobenzophenone, 4-nitroben Zalmalondinitrile, α-cyano-β- (p-cyanophenyl) ethyl acrylate, 9-anthracenylmethylmalondinitrile, 1-cyano-1- (p-nitrophenyl) -2-
Examples thereof include electron-withdrawing compounds such as (p-chlorophenyl) ethylene and 2,7-dinitrofluorenone.

In addition, as additives to the photoreceptor, an antioxidant, an anti-curl leveling agent, etc. can be added as required.

The hydrazone compound of the present invention is dissolved or dispersed in a suitable solvent together with the above-mentioned various additives according to the form of the photoreceptor, and the coating solution is coated on the above-mentioned conductive support. Then, the photoconductor is manufactured by drying. As the coating solvent, aromatic hydrocarbons such as benzene, toluene, xylene, and monochlorobenzene, solvents such as methylene chloride, dichloroethane, dioxane, dimethoxymethyl ether, and dimethylformamide may be used alone or as a mixed solvent of two or more kinds, or if necessary. Further, a solvent such as alcohols, acetonitrile or methyl ethyl ketone can be further added and used.

[0047]

EXAMPLES The present invention will now be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

Synthesis Example 1 (Exemplified Compound No. 1) Benzaldehyde and 1,1-diphenylhydrazine hydrochloride were reacted in ethanol using potassium acetate as a catalyst to give benzaldehyde diphenylhydrazone (melting point: 118.0 to 120.0 ° C.). To get The hydrazone derivative thus obtained was formylated with dimethylformamide and phosphorus oxychloride to give a formyl derivative (melting point: 11
3.5 to 115.0 ° C) is obtained. Next, this formyl compound and diphenylhydrazine hydrochloride (Structural formula (V) A = phenyl group, B = phenyl group) are heated to reflux in ethanol in the presence of potassium acetate to exemplify Compound No. 1
(Melting point 164.0-165.0 ° C.) can be easily obtained. The recrystallization solvent was ethanol.

Examples 1 to 5 A polyester film (thickness: 80 μm) vapor-deposited on aluminum was used as a support, and the following structural formula

[0050]

[Chemical 8] 1% T in which a polyvinyl butyral resin (Eslec B manufactured by Nisshin Chemical Industry Co., Ltd.) is dissolved in the bisazo pigment represented by
The same amount by weight as the resin is added to the HF solution, and then 1.5 m in diameter in a paint conditioner (manufactured by Red Level)
m glass beads were dispersed together for about 2 hours, and the mixture was dried by the doctor blade method. The film thickness after drying was 0.2μ.

On the pigment layer (charge generation layer), the exemplified compounds of the present invention (No. 1, No. 3, No. 17, No.
39, No. 57 g of each 1 g of polyarylate resin (U-100 manufactured by Unitika) in 15% methylene chloride was applied by a squeegee doctor.
A resin-hydrazone compound solid solution phase (charge transfer layer) having a dry film thickness of 25 μm was prepared.

Laminated electrophotographic feeling created in this way
Electrostatic recording paper tester (SP-428 manufactured by Kawaguchi Denki)
The electrophotographic characteristics were evaluated by. The measurement conditions are (applied potential -6
KV, static No3), white light irradiation (irradiation
Attenuation from -700V to -100V by light = 5lux)
The amount of exposure E required ₁₀₀(Looks and seconds) and initial power
Rank V₀(-Volt) was measured, and the value is shown in Table 8.

Further, by using the same apparatus, charging-static elimination (static elimination light:
White light at 40 lux for 1 second) was set as one cycle, and the same operation was repeated 10,000 times, and the initial potential V ₀ (−volt) and E ₁₀₀ (lux · second) were measured to obtain V ₀ and E.
Changes in ₁₀₀ were investigated and are shown in Table 8.

[0054]

[Table 8]

From Table 8, it was found that the hydrazone compound of the present invention has good sensitivity repeating characteristics.

Example 6 x-type metal-free phthalocyanine (Fastgen Blue 8 manufactured by Dainippon Ink and Chemicals, Inc.) was formed on a polyester film vapor-deposited on aluminum.
120) 0.4 g and 0.3 g of a vinyl chloride: vinyl acetate copolymer resin (Slex M, manufactured by Sekisui Chemical Co., Ltd.) was added to 30 ml of an ethyl acetate solution, and dispersed in a paint conditioner for about 20 minutes to obtain a doctor blade method. And a charge generation layer was formed so that the film thickness after drying was 0.4 μm.

Exemplified Compound No. 59 was formed on the charge generation layer.
Containing 50% hydrazone compound by weight
Thus, a photoreceptor having a two-layer structure was prepared by laminating a coating layer.
The spectral sensitivity at 780 nm of this photoreceptor was required to reduce the potential to half.
Energy (E_Fifty) And initial potential (-V₀) Where V was found
₀= 850 (-volt), E_Fifty= 3.9 (erg / cm
²) Is a highly sensitive and highly charged photoconductor.
It was Also, a Sharp laser printer (WD-58
0P) is modified, and the photoconductor is glued to the drum part,
Empty copy (Non Copy Aging) 10,000 times
After that, the degree of decrease in initial potential and sensitivity was examined. So
Results in V₀= 840 (-volt), E _1/2= 4.0
(Erg / cm²) And most of the values are changed compared to the first time.
No movement was seen.

Examples 7 to 10 Alumite processing of aluminum substrate surface (alumite layer 7μ)
1 g each of the hydrazone compound of the present invention, and a polyarylate resin 1.1 represented by the following structural formula (Formula 9) on the prepared support.
g, N, N-3,5-xylyl-3,4-xylyl-
A solution prepared by dissolving 0.15 g of 3,4,9,10-perylenetetracarboxylic imide and 0.05 g of an ultraviolet absorber in methylene chloride (the imide compound was partially dispersed) was applied with an applicator to obtain a dry film having a thickness of 20 μ. A layer photoreceptor was obtained.

[0059]

[Chemical 9]

The electrophotographic characteristics of the thus obtained photoconductor were measured by an electrostatic recording paper tester. The measurement conditions were (applied voltage +5.5 KV, static No. 3). Measure the exposure dose E ₁₀₀ (lux seconds) required to reduce from +700 V to +100 V by white light irradiation,
The values are shown in Table 7. In addition, Table 9 also shows the degree of reduction in sensitivity (E ₁₀₀ ) after an empty copy test was performed 10,000 times.

[0061]

[Table 9]

It has been found that the photoreceptor using the hydrazone compound of the present invention is a photoreceptor having excellent sensitivity and durability even in positive charging.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kazuhiro Enomoto 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka

Claims (4)

[Claims] 1. A photosensitive layer formed on a conductive support is represented by the following general formula (I): (In the formula, A and B are an aryl group which may have a substituent, an aralkyl group which may have a substituent, a heterocyclic group which may have a substituent, or an alkyl group having 1 to 4 carbon atoms, and R ¹
Is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms, and R ² may contain a hydrogen atom, an alkenyl group having 2 to 3 carbon atoms, or a substituent. It is a heterocyclic group, an alkyl group having 1 to 4 carbon atoms, or an aryl group which may have a substituent, and R ³ includes an aryl group which may have a substituent, an aralkyl group which may have a substituent, and a substituent. May be a heterocyclic group or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1,2,3. However, when n is 2 or 3, R ^1's may be the same or different, and may further form a methylenedioxy ring. ) An electrophotographic photosensitive member comprising a hydrazone compound represented by 2. A hydrazone compound represented by the general formula (I) is represented by the following general formula (II): (In the formula, a is a hydrogen atom, a halogen atom, an alkyl group having 1 to 3 carbon atoms, or an alkoxy group having 1 to 3 carbon atoms.
¹ , R ² , R ³ , B and n have the same meanings as in formula (I). The electrophotographic photoreceptor according to claim 1, which is a compound represented by the formula (1). 3. The photosensitive layer contains a carrier-transporting substance and a carrier-generating substance, and the carrier-transporting substance is represented by the general formula (I).
The electrophotographic photoreceptor according to claim 1, which is a hydrazone compound of 4. The photosensitive layer comprises a laminate of a carrier generating layer containing a carrier generating substance and a carrier transporting layer containing a carrier transporting substance, and the carrier transporting substance is represented by the general formula (I). The electrophotographic photoreceptor according to claim 1, which is a compound.