JPH02210452A - Photosensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity and electrostatic chargeability and to reduce fatigue and deterioration in case of repeated use by forming a photosensitive layer contg. a specified hydrazone compd. on an electrically conductive support. CONSTITUTION:A photosensitive layer contg. a hydrazone compd. represented by formula I is formed on an electrically conductive support. In the formula I, each of R1 and R2 is H, alkyl, etc., Z is a residue forming a condensed ring together with a benzene ring, each of Ar1 and Ar2 is alkyl which may have a substituent, aryl, etc., each of Ar3 and Ar4 is H, alkyl which may have a substituent, aryl, etc., both of Ar3 and Ar4 are not H, and Ar1 and Ar2 or Ar3 and Ar4 may bond to each other to form a ring. Such characteristics of the resulting photosensitive body as the sensitivity, electric charge transferring property, initial surface potential and dark attenuation rate are improved and optical fatigue due to repeated use is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a photoreceptor having a photosensitive layer containing a novel hydrazone compound.

Conventional Technologies and Problems In general, in electrophotography, the surface of the photosensitive layer of a photoreceptor is charged and exposed to form an electrostatic latent image, which is developed with a developer to make it visible, and the visible image is directly printed as is. A direct method in which the visible image on the photoreceptor is fixed on a photoreceptor to obtain a copy image, a powder image transfer method in which the visible image on the photoreceptor is transferred onto a transfer material such as paper, and the transferred image is fixed to obtain a copy image; The electrostatic latent image on the photoreceptor is transferred onto transfer paper, and the electrostatic latent image on the transfer paper is developed.
A fixing latent image transfer method is known.

Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been known as materials constituting the photosensitive layer of a photoreceptor used in this type of electrophotography.

While these photoconductive materials have a number of advantages, such as low charge dissipation in the dark or rapid charge dissipation upon irradiation with light,
It has various drawbacks.

For example, with selenium-based photoreceptors, the manufacturing conditions are difficult.
It is expensive to manufacture and must be handled with care as it is susceptible to heat and mechanical shock. With cadmium sulfide photoreceptors and zinc oxide photoreceptors, stable sensitivity cannot be obtained in humid environments, and the dye added as a sensitizer causes charging deterioration due to corona charging and photobleaching due to exposure, so they cannot be used for long periods of time. It has the disadvantage that it cannot provide stable characteristics over a long period of time.

On the other hand, in functionally separated photoreceptors such as polyhinyl carhasol, many organic compounds have been mentioned as charge transport materials used in the charge transport layer, but in practice there are various problems. .

For example, 2,5-his(P-diethylaminophenyl) 1 described in U.S. Pat. No. 3,189,447
．． 3.4-Oxadiazole has low compatibility with binders and tends to precipitate crystals. U.S. Patent No. 3.820,
The diarylalnonone derivatives described in Japanese Patent No. 989 either have good compatibility with the binder or change in sensitivity when used repeatedly. Also, JP-A-54-5
The hydrazone compound described in Publication No. 9143 is
The residual potential characteristics are relatively good, but the charging ability and repeatability characteristics are poor. The reality is that there are almost no low-molecular-weight organic compounds that have practically desirable properties for producing photoreceptors.

In addition, JP-A No. 58-65275 describes the following: Various organic photoconductive polymers have been proposed, and these polymers have better film-forming properties and lighter weight than the aforementioned inorganic photoconductive materials. It is superior in that respect, and still has sufficient sensitivity,
It is inferior to inorganic photoconductive materials in terms of durability and stability against environmental changes.

In addition, low molecular weight organic photoconductive compounds are preferable in that the physical properties or electrophotographic properties of the film can be controlled by selecting the type and composition ratio of the binder used in combination; Since it is used in combination with materials, high compatibility with the binder is required.

Photoreceptors in which these high-molecular-weight and low-molecular-weight organic photoconductive compounds are dispersed in a binder resin have drawbacks such as high residual potential and low sensitivity due to a large number of carrier traps. Therefore, it has been proposed to incorporate a charge transporting material into the photoconductive compound to solve the above-mentioned drawbacks.

Furthermore, a functionally separated photoreceptor has been proposed in which the charge generation function and the charge transport function of the photoconductive function are assigned to separate substances. Thus, a hydrazone compound represented by 2 [wherein R3, R2, R3, and R1 represent those described in the above publication] is described.

JP-A No. 63-249150 describes the following general [formula A
, B, R, , R2, R3, R3, and R5 are not described in the above publication, but the hydrazone compound represented by 1 is described.

JP-A No. 63-249151 describes a hydrazone compound represented by the following - Monana [where A, , B, R, , R2, R3, and R4 represent those described in the above publication]. ing.

However, these compounds are completely different in structure from the compounds of the present invention.

The present invention has been made in view of the above facts, and contains a hydrazone compound that has excellent compatibility with binders and charge transport ability, has excellent sensitivity and charging ability, and can be used repeatedly. It is an object of the present invention to provide a photoreceptor which suffers little fatigue deterioration when exposed to the atmosphere and has stable electrophotographic characteristics.

Means for Solving the Problems The present invention relates to a photoreceptor having a photosensitive layer containing a hydrazone compound represented by the following general formula [I] on a conductive support, and the styryl structure is effective for sensitivity. The 1-herasin compound of the present invention is a compound excellent in both properties. This characteristic cannot be obtained simply by mixing a compound having a hydrazone structure and a styryl compound.

In the hole [1], Ar, Ar2, Ar3 and Ar independently represent an alkyl group, an aryl group, a fused polycyclic group or a heterocyclic group, and Ar3 and Ar are either one of them. Although it may be a hydrogen atom, both of them are not hydrogen atoms. Preferred Ar, ~Ar, is an electron-donating group. In particular, it is preferred that Ar3 and Ar are both phenyl groups.

Ar, and Ar2, and Ar3 and Al-4 may be combined to form, for example, a ring such as carbazole.

Ar, , Ar2, Ar3 or Ar may have a substituent, and such substituent is preferably an electron-donating one, such as a substituted amine group, an alkokyne group such as methquino or etquino, etc. Can be done. It is preferable that Ar3 and Ar4 have such substituents.

[In the formula, R4 and R2 each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom: Z represents a residue that forms a condensed ring with a benzene ring, and even if it has a substituent Good; Ar.

and Ar2 is independently an alkyl group which may have a substituent, an allyl group which may have a substituent, a fused polycyclic group which may have a substituent, or a substituent. does not indicate an optional heterocyclic group; A r 3 and Ar
, independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted fused polycyclic group, or a substituent Indicates a heterocyclic group which may have Ar3 and Ar
, except when both are hydrogen atoms, and Ar, and Ar
2. Ar3 and Ar may be combined to form a ring. ] The hydrazone compound shown by Monena [11] has both a hydrazone structure and a styryl structure. The hydrazone structure is effective for ozone resistance, and in the hole [1], RI and R2 each represent a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom.

Z represents a residue that forms a condensed ring with the benzene ring,
It may have a substituent.

Preferred specific examples of the hydrazone compound represented by the general formula [I] of the present invention include those having the following structural formula, but are not limited thereto.

(Hereinafter, blank space) In the present invention, compounds [5], [6], [7], [
81, [11], [12], [14], [151, [1
8], [21], [221, [251, [27J, [3
o] is preferred.

The compound represented by the general formula [■] of the present invention can be easily synthesized by a conventional method.

An example is an aldehyde compound represented by the following - Monana [■] [In the formula, R1, R2, Z, Ar3, Ar, have the same meaning as (1)] and the following - Monana [■];
It can be synthesized by condensing a hydrazine compound represented by [where Ar, Ar2 has the same meaning as [I]].

The reaction is generally carried out by azeotropically removing the water produced using an aromatic solvent such as benzene, toluene, or xylene, or an alcoholic solvent such as methanol, ethanol, or butanol, or using potassium acetate or p-1-luenesulfone. It is carried out using a catalyst such as acid or acetic acid.

The photoreceptor of the present invention has a photosensitive layer containing one or more hydrazone compounds represented by the general formula [I].

Various types of photoreceptors are known, and the photoreceptor of the present invention may be any of them.

Examples include a single-layer photoreceptor in which a charge-generating material and a photosensitive layer made of a hydrazone compound dispersed in a resin binder are provided on a support, or a charge-generating layer mainly composed of a charge-generating material is provided on a support. There are also so-called laminated photoreceptors in which a charge transport layer is provided on the soil. Although the hydrazone compound of the present invention is a photoconductive substance, it acts as a charge transport material and can transport charge carriers generated by absorbing light extremely efficiently.

In order to produce a single-layer type photoreceptor, fine particles of a charge generating material may be dispersed in a resin solution or a solution containing a charge transporting material and a resin, and this may be applied onto a conductive support and dried. The thickness of the photosensitive layer at this time may be 3 to 30 .mu.m, preferably 5 to 20 .mu.m. If the amount of the charge generating material used is too small, the sensitivity will be poor, and if it is too large, the charging property will be poor and the mechanical strength of the photosensitive layer will be weakened. 0.01 to 3 parts by weight, preferably 0.2 to 2 parts by weight.

To produce a laminated photoreceptor, a charge-generating material is vacuum-deposited on a conductive support, or dissolved in a solvent such as amine and coated. A coating solution prepared by dispersing a binder resin in a solution is coated and dried, and then a solution containing a charge transporting material and a binder is coated and dried.

At this time, the thickness of the charge generation layer may be 4 μm or less, preferably 2 μm or less, and the charge transport layer may have a thickness of 3 to 30 μm.
Preferably it is 5 to 20 μm.

The ratio of the charge transport material in the charge transport layer is 0.2 to 2 parts by weight, preferably 0.3 to 1 part by weight, per 1 part by weight of Pineta resin.
It is 3 parts by weight.

The photoreceptor of the present invention contains a binder resin and a plasticizer such as halogenated paraffin, polychlorinated hyphenyl, dimethylnaphthalene, dibutyl phthalate-1., ○-taphenyl, talolanil, tetraanoethylene, 2.4.7-)
Electron-withdrawing sensitizers such as linitrofluorenone, 5.6-ziniatupenzoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride, 3.5 mite 1-benzoic acid,
Methyl violet, locumin B1 cyanine dye,
Sensitizers such as pyrylium salts and thiapyrylium salts may also be used.

Further, antioxidants, ultraviolet absorbers, dispersion aids, anti-settling agents, etc. may also be used as appropriate.

As the electrically insulating binder resin used in the present invention, electrically insulating binders such as thermoplastic resins, thermosetting resins, photocuring resins, photoconductive resins, etc., which are known per se, can be used. .

Examples of suitable binder resins include, but are not limited to, saturated polyester resins, polyamide resins, acrylic resins, ethylene-vinyl acetate resins, ionically crosslinked olefin copolymers (ionomers), styrene-butadiene. Block copolymers, boritunopofu-1, hinyl chloride-hinyl acetate copolymers, cellulose esters, polyimides, thermoplastic resins such as styrene resins, evoquino resins, urethane resins, silicone resins, phenolic resins, melamine resins, xylene resins, These include thermosetting resins such as alkyd resins and thermosetting acrylic resins, photocurable resins, and photoconductive resins such as polyvinylcarbazole, polyvinylpyrene, polyvinylanthracene, and polyvinylpyrrole.

These can be used alone or in combination.

These electrically insulating resins are 1×1o12 when measured alone.
It is desirable to have a volume resistivity of Ω·cm or more.

Charge-generating materials include bisazo pigments, triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, cyanine dyes, styryl dyes, pyrylium dyes, azo pigments, quinacridone pigments, and indigo dyes. Pigments, perylene pigments, polycyclic quinone pigments, hisbenzimidacyl pigments, induthrone pigments, squalium base pigments, asrene pigments, and 7-talocyanine pigment transport material (2) were blended into the binder. This is a photoreceptor on which a photosensitive layer (4) is formed, and the hydrazone compound of the present invention is used as a charge transporting material.

Figure 2 shows a functionally separated photoreceptor that has a charge generation layer (6) and a charge transport layer (5) as photosensitive layers, and the charge transport layer (5) is formed on the surface of the charge generation layer (6). ing.

The hydrazone compound of the present invention is blended into the charge transport layer (5).

Figure 3 shows a functionally separated photoreceptor having a charge generation layer (6) and a charge transport layer (5) as in Figure 2, but contrary to Figure 2, the charge transport layer (5) is A charge generation layer (6) is formed on the surface.

FIG. 4 shows an additional surface protective layer (
7), and the photosensitive layer (4) is provided with a charge generation layer (
6) and a functionally separated photoreceptor having charge transport N(5).

Materials used for the surface protective layer include acrylic resin,
Polymers such as polyaryl resins, polycarbonate resins, and urethane resins can be used as they are, organic substances such as selenium, selenium alloys such as selenium/tellurium, selenium/arsenic, etc.
Examples include inorganic substances such as cadmium sulfide, cadmium selenide, zinc oxide, and amorphous silicon. In addition to these materials, any material can be used as long as it absorbs light and generates charge carriers with an extremely high probability.

As the conductive support used in the photoreceptor of the present invention, a sheet or drum-shaped foil or plate of metal or alloy such as copper, aluminum, silver, iron, zinc, or nickel is used; A metal is vacuum-deposited or electrolessly plated on a plastic film, etc., or a layer of a conductive compound such as a conductive polymer indium oxide or tin oxide is coated or vapor-deposited on a support such as paper or a plastic film. The one given is used.

Examples of the structure of a photoreceptor using the hydrazone compound of the present invention are schematically shown in FIGS. 1 to 5.

In FIG. 1, a substrate (1) in which a photoconductive material (3) and a low resistance compound such as tin oxide or indium oxide are dispersed is suitable.

FIG. 5 shows an intermediate layer (8) between the substrate (1) and the photosensitive layer (4).
), and the intermediate layer (8) has improved adhesion,
It can be provided to improve coating properties, protect the substrate, and improve charge injection from the substrate to the photosensitive layer.

Materials used for the intermediate layer include polymers such as polyimide, polyamide, nitrocellulose, polyhinyl butyral, and polyvinyl alcohol, either as they are, or in which low-resistance compounds such as tin oxide or indium oxide are dispersed, aluminum oxide, and polymer oxide. Vapor deposited films of zinc, silicon oxide, etc. are suitable.

Further, the thickness of the intermediate layer is preferably 1 μm or less.

Lifebed Man (Synthesis of Compound Example [5]) Aldehyde compound represented by the following formula; 4.15 parts by weight of CHO and 2.21 parts by weight of 1,1-diphenylhydrazine hydrochloride were added to 200+J of ethanol at reflux temperature. The mixture was heated under reflux for 2 hours and reacted with a small amount of acetic acid.

After cooling, water was added to precipitate crystals. Thereafter, the precipitate was filtered, washed with n-hexano, and purified by recrystallization using acetone-methanol to obtain 3.4 parts by weight of yellow crystals (yield 778%). Elemental analysis is as follows.

Example 1 The exposure amount E1/2 (Iux-s
ec), the decay rate DDR, (%) of the initial potential when left in the dark for 1 second was measured.

Examples 2 to 4 Same structure as in Example 1, except that hydrazone compounds [3], [5], and [6] were used in place of hydrazone compound [2] used in Example 1. A photoreceptor was produced.

V was applied to the thus obtained photoreceptor in the same manner as in Example 1. , E, /2, D D R+ was measured.

Example 5 Hisazo compound Cθ represented by the following general formula [B] 0.45 parts, polystyrene resin (molecular weight 40,000) 0
．． 45 parts were dispersed with 50 parts of ncrohexanone in a sand grinder. The resulting dispersion of the hisazo compound was dispersed in a sand gliter together with 0.45 parts of aluminum having a thickness of 100 μm, 045 parts of polyester resin (Vylon 200; manufactured by Toyobo Co., Ltd.), and 50 parts of total socisoclosanone.

The obtained dispersion of the hisazo compound was applied onto a 100 μm thick aluminized mylar using a film applicator to a dry film thickness of 0.3 g/m 2 and then dried. 70 parts of hydrazone compound [2] and polycarbonate resin (K
A solution prepared by dissolving 70 parts of -[300; manufactured by Ondai Kasei Co., Ltd.] in 400 parts of 1.4 dioxane was applied to a dry film thickness of 16 μm to form a charge transport layer. In this way, 2
An electrophotographic photoreceptor having a photosensitive layer consisting of layers was obtained.

The thus obtained photoreceptor was used as a commercially available electrophotographic copy 1 (EP).
-4702; manufactured by Minolta Camera Co., Ltd.), and was corona charged at 6 KV, and the initial surface potential was V. (V) Using a film applicator on chemically coated mylar, the dry film thickness is 0.3
It was coated at a concentration of g/m2 and then dried. A hydrazone compound (7:
] 70 parts and polyarylate resin (U-1,00; manufactured by Unitika Co., Ltd.) 70 parts dissolved in 400 parts of 1.4 dioxine was applied to a dry film thickness of 161.1 m. , a charge generation layer was formed. In this manner, an electrophotographic photoreceptor having a two-layer photosensitive layer was produced.

Examples 6 to 8 Same structure as in Example 5, except that hydrazone compounds [10], [11], and [15] were used in place of hydrazone compound [7] used in Example 5. A photoreceptor was produced.

The thus obtained photoreceptor was subjected to the same method as in Example 1. , El/2, DDR, were measured.

Example 9 50 parts of copper phthalo/anine and 0.2 parts of tetraniphthalocyanine were dissolved in 500 parts of 98% concentrated sulfuric acid with thorough stirring, and this was poured into 5000 parts of water to dissolve copper phthalonanine, tetrani), and phthalocyanine. After depositing the photoconductive material composition, it was filtered, washed with water, and heated at 120'C under reduced pressure.
! and dried.

10 parts of the photoconductive composition thus obtained was added to a thermosetting acrylic resin (Acrydik A405 manufactured by Dairoki Ink Co., Ltd.).
22.5 parts, melamine plant] fat (Super Vesotunomine J8
20. 75 parts (manufactured by Inuroki Ink Co., Ltd.), 15 parts of the above-mentioned hydrazone compound (1,7), and a mixed solvent of 1. A photosensitive coating liquid was prepared by dispersing it together with O0 part in a ball mill bond for 48 hours, and this coating liquid was applied onto an aluminum substrate and dried to form a photosensitive layer with a thickness of about 15 μm to prepare a photoreceptor.

The thus obtained photoreceptor was subjected to corona charging in the same manner as in Example 1, except that corona charging was performed at +6 KV. ,E,/
2. DDR was measured.

Examples 1O to 12 Same structure as in Example 9, except that instead of hydrazone compound [17] used in Example 9, hydrazone compounds [21], [25], [2] were used. V in the same manner as in Example 9 for the photoreceptor. , El/2
, DDR, was measured.

Comparative Examples 5 to 8 Same method and same structure as Example 9, except that the following hydrazone compounds CG), [I]], [I], [ A photoreceptor was produced in exactly the same manner as in Example 9 except that each of the photoreceptors was used.

2H5 7] were prepared.

The thus obtained photoreceptor was subjected to the same method as in Example 9. , El/2, DDR, were measured.

Comparative Examples 1 to 4 Same structure as in Example 9, except that the following compounds [C], [D], [E], CF'l were used in place of the hydrazone compound [171] used in Example 9. A photoreceptor was produced in exactly the same manner as in Example 9 except that each of the following was used.

The thus obtained photoreceptor was subjected to the same method as in Example 9. , E1/2, and DDR.

V of the photoreceptors obtained in Examples 1 to 12 and Comparative Examples 1 to 8.

, El/2, DDR, are summarized in Table 1.

Table 1 Table l (Continued) As can be seen from Table 1, the photoreceptor of the present invention has sufficient charge retention ability whether it is a laminated type or a single layer type, and the dark decay rate is also sufficient to be used as a photoreceptor. It is small and has excellent sensitivity.

Furthermore, repeated actual copying tests were conducted on the photoconductor of Example 9 during positive charging using a commercially available electrophotographic copying machine (EP-3502 manufactured by Minolta Chikaramera Co., Ltd.). 3. Photoconductive material 4... Photosensitive layer 5... Charge transport layer 6... Charge generating layer 7... Surface protective layer 8... Intermediate layer Patent applicant Minolta Nonomera Co., Ltd. Agent Patent attorney It can be seen that the final image of 16 Aoyama has excellent gradation, there is no change in sensitivity, and a clear image is obtained, indicating that the photoreceptor of the present invention has stable repeatability.

Effect of the invention The present invention provides photoconductive compounds useful in photoreceptors.

The photoconductive compounds of the present invention are particularly useful as charge transport materials.

The photoreceptor containing the hydrazone compound of the present invention has excellent photoreceptor properties such as sensitivity, charge transportability, initial surface potential, and dark decay rate, and has little optical fatigue due to repeated use.

[Brief explanation of the drawing]

FIGS. 1 to 5 are schematic diagrams of photoreceptors according to the present invention, and FIGS. 1, 4, and 5 are dispersion type photoreceptors in which a photosensitive layer is laminated on a conductive support. 2 and 3 show the structure of a functionally separated photoreceptor in which a charge generation layer and a charge transport layer are laminated on a conductive support.

Claims (1)

[Claims] 1. A photoreceptor having a photosensitive layer containing a hydrazone compound represented by the following general formula [I] on a conductive support: ▲There are mathematical formulas, chemical formulas, tables, etc.▼[I] [ In the formula, R_1 and R_2 are each independently a hydrogen atom,
Indicates an alkyl group, an alkoxy group or a halogen atom;
Z represents a residue that forms a condensed ring with the benzene ring,
May have a substituent; Ar_1 and Ar_2 are independently an alkyl group that may have a substituent, an aryl group that may have a substituent, or an aryl group that may have a substituent. Indicates a good fused polycyclic group or a heterocyclic group optionally having a substituent; Ar_3 and Ar_4 are independently,
A hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, a fused polycyclic group which may have a substituent, or a substituent. indicates a good heterocyclic group; except when Ar_3 and Ar_4 are both hydrogen atoms; and Ar_1 and Ar_2, A
r_3 and Ar_4 may be combined to form a ring. ]