JPH02210451A - 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., R3 is H, alkyl which may have a substituent, aralkyl which may have a substituent, etc., 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]

INDUSTRIAL APPLICATION FIELD The present invention relates to a photoreceptor having a photosensitive layer containing a novel hydrazone compound. BACKGROUND TECHNOLOGY AND PROBLEMS Generally, in electrophotography, the surface of the photosensitive layer of a photoreceptor is charged,
A direct method involves exposing to light to form an electrostatic latent image, developing it with a developer to make it visible, and directly fixing the visible image on the photoreceptor to obtain a copy image. A powder image transfer method in which a visual image is transferred onto a transfer material such as paper and the transferred image is fixed to obtain a copy image, or a powder image transfer method in which an electrostatic latent image on a photoreceptor is transferred onto a transfer paper and the electrostatic charge on the transfer paper is transferred. Develop the latent image,
A fixing latent image transfer method is known. Inorganic photoconductive materials such as selenium, gadmium sulfide, and zinc oxide have been known as materials constituting the photosensitive layer of a photoreceptor used in this type of electrophotography. Although these photoconductive materials have many advantages, such as low charge dissipation in the dark or rapid charge dissipation when exposed to 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. Cadmium sulfide photoreceptors and zinc oxide photoreceptors do not provide stable sensitivity in humid environments, and the dyes added as sensitizers cause 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, various organic photoconductive polymers including polyvinylcarbazole have been proposed, and many organic compounds have been cited as charge transport materials to be used, but in practice they have 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 diarylalkane derivatives described in Japanese Patent No. 989 have good compatibility with binders, but sensitivity changes occur when used repeatedly. Also, JP-A-5/4-5
The hydrazone compound described in Publication No. 9143 is
The residual potential characteristics are relatively good, but the charging ability and repetition 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, Japanese Patent Application Laid-Open No. 57-11350 describes the following:
Although they are excellent in terms of film formability and light weight, they are still inferior to inorganic photoconductive materials in terms of sufficient sensitivity, 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 a photoconductive compound to solve the above-mentioned drawbacks. Further, 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. In such a functionally separated photoreceptor, R, , R2, R3, and R are used in the charge transport layer.
6 represents the compound described in the above-mentioned publication]. JP-A-58-131954 describes a hydrazone compound represented by the following formula: [wherein R1, R2, R3, and R are not as described in the above publication]. However, these compounds are completely different in structure from the compounds of the present invention. Problems to be Solved by the 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 that exhibits less fatigue deterioration when exposed to the atmosphere and has stable electrophotographic characteristics. Means for Solving the Problems The present invention relates to a photoconductor having a photoconductor layer containing a hydrazone compound represented by the following formula [I] on a conductive support: [wherein R11R2 are each independently Represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom: R1
does not represent a hydrogen atom, or an alkyl group, an aralkyl group, an aryl group, a fused polycyclic group, or a heterocyclic group, each of which may have a substituent: Ar and Ar independently represent a substituent. An alkyl group that may have an optional substituent, an aryl group that may have a substituent, a fused polycyclic group that may have a substituent, or a heterocyclic group that may have a substituent. shown; Ar3 and Ar4 are independently hydrogen atoms,
It is preferred that both of and Ar are phenyl groups. Ar, and Ar2, and Ar3 and Ar 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 amino group, or an alkoxy group such as methoxy or ethoxy. Can be done. Ar
3 and Ar preferably have such a substituent. In general formula [1], R1 and R2 are each a hydrogen atom,
Indicates an alkyl group, an alkoxy group, or a halogen atom. R3 is a hydrogen atom, each of which has a substituent and represents an alkyl group, an aralkyl group, an aryl group, a fused polycyclic group, or a heterocyclic group. The hydrazone represented by the general formula [■] of the present invention Preferred specific examples of the compound include, but are not limited to, those having the following structural formula: an alkyl group that may have a substituent; Does not indicate a good aryl group, a fused polycyclic group that may have a substituent, or a heterocyclic group that may have a substituent; except when Ar3 and Ar4 are both hydrogen atoms. ; Also, Ar, and Ar2, and Ar3 and Ar may be combined to form a ring.] A hydrazone compound indicated by a crest [+] has both a hydrazone structure and a styryl structure. The hydrazone structure is effective for ozone resistance, and the styryl structure is effective for sensitivity.The hydrazone compound of the present invention is a compound that is excellent in both properties.This property is obtained simply by mixing a compound with a hydrazone structure and a styryl compound. - In Monka [I], Ar, Ar2, Ar3 and Ar independently represent an alkyl group, an aryl group, a fused polycyclic group or a heterocyclic group, and further Ar3, Either one of Ar and -Ar+ may be a hydrogen atom, but neither of them is a hydrogen atom.Ar and -Ar+ are preferably electron-donating groups.In particular, ArL10] 1■ [15] [16 ] [17] (hereinafter, margin) [11] [12] [13] [13J [30] [321 [331] [26] [271 [28] [29] [34 [35] [361] In the present invention , Compounds [41, [7], [8], [9], [1 1], [141, [161, [17], [18], [19], [22], [23], [271] , [28], [291, and [30] are preferred. The compound represented by the general formula (I) of the present invention can be easily synthesized by a conventional method. For example, the following - Monana [■]: (In the formula, R3, R2, R3, Ar3, Ar have the same meanings as (I))] and the following - Monana [■]: [
It can be synthesized by condensing a hydrazone compound represented by [1] in which Ar, , Ar 2 has the same meaning as [1]. 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, Utahol, propatool, or butanol, or using potassium acetate or p-toluenesulfone. 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 styryl compounds represented by the above-mentioned -pattern CD. Various types of photoreceptors are known, and the photoreceptor of the present invention may be any of them. For example, a single-layer photoreceptor has a charge-generating material and a photosensitive layer formed by dispersing a hydrazone compound in a resin binder on a support, or a single-layer photoreceptor has a charge-generating layer mainly composed of a charge-generating material on a support, There is a so-called laminated photoreceptor having a charge transport layer provided thereon. 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. To fabricate a single-layer photoreceptor, fine particles of a charge-generating material are dispersed in a resin solution or a solution containing a charge-transporting material and a resin, and this is coated on a conductive support and dried. good. The thickness of the photosensitive layer at this time is 3 to 30 μm1
Preferably it is 5 to 20 μm. If the amount of the charge-generating material used is too small, the sensitivity will be poor, and if it is too large, the chargeability will be poor and the mechanical strength of the photosensitive layer will be weakened. te 0.01～
The amount may be 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 it is dissolved in a solvent such as amine and applied, or the pigment is coated with a suitable solvent or, if necessary, with a painter. It is obtained by applying and drying a coating liquid prepared by dispersing a resin in a solution, and then coating and drying a solution containing a charge transport material and a binder thereon. At this time, the thickness of the charge generation layer is preferably 4 μm or less, preferably 2 μm or less, and the charge transport layer has 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 the binder resin.
．． It is 3 parts by weight. In addition to the binder resin, the photoreceptor of the present invention includes plasticizers such as hacogenated paraffin, polychlorinated hypohenyl, dimethylnaphthalene, dibutyl phthalate, and 0-taphenyl, and talolanil, tetracyanoethylene, 2,4.74-linitrofluorenone, and 5.6 - dicyatubensoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride,
Electron-withdrawing sensitizers such as 3,5 dinitrobenzoic acid, sensitizers such as Medill Violet, Rhodamine B1 cyanine dye, pyrylium salts, thiapyrylium salts, etc. may 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, polycarbonates, hinyl chloride-vinyl acetate copolymers, cellulose esters, polyimides, thermoplastic resins such as styrene resins, epoxy resins, urethane resins, silicone resins, phenolic resins, melamine resins, xylene resins, acrylic resins, heat Thermosetting resin such as cured acrylic resin: Photocurable resin: Photoconductive resin such as polyvinylcarbazole, polyhinylpyrene, polyhinyl anthracene, polyhinylpyrrole, etc. These can be used alone or in combination. These electrically insulating resins have a resistance of 1×1012 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, xanthine dyes, anine dyes, styryl dyes, pyrylium dyes, azo pigments, quinacridone pigments, and indigo dyes. Pigment, perylene Examples of the structure of a photoreceptor using the hydrazone compound of the present invention are schematically shown in FIGS. 1 to 5. Figure 1 shows a photoreceptor in which a photosensitive layer (4) containing a photoconductive material (3) and a charge transporting material (2) as a binder is formed on a substrate (1). The hydrazone compounds of the present invention are used. Figure 2 shows a functionally separated photoreceptor having 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, or a charge transport layer (5) as opposed to Figure 2. 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 a charge transport layer (5). organic substances such as pigments, polycyclic quinone pigments, hisbenzimidacyl pigments, induthrone pigments, squalium ring pigments, asrene pigments, phthalocyanine pigments, selenium, selenium/tellurium, selenium/arsenic, etc. Examples include inorganic materials such as selenium alloys, 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. The conductive support used in the photoreceptor of the present invention may be a sheet or drum-shaped foil or plate of metal or alloy such as copper, aluminum, silver, iron, zinc, or nickel; 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. used. Materials used for the surface protective layer include acrylic resin,
Suitable examples include polymers such as polyaryl resins, polycarbonate resins, and urethane resins as they are, or those in which low-resistance compounds such as soot oxide and indium oxide are dispersed. 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 polyhinyl alcohol as they are, or polymers in which low-resistance compounds such as tin oxide and indium oxide are dispersed, and oxidized materials. Vapor deposited films of aluminum oxide, zinc oxide, silicon oxide, etc. are suitable. Further, the thickness of the intermediate layer is desirably 1 μm or less. (Synthesis of Compound Example [12]) An aldehyde compound represented by the following formula; 4.05 parts by weight and 2.21 parts by weight of 1-1-radine hydrochloride on 1,1-diphenyl were dissolved in 200 mQ of ethanol at reflux temperature. Then, the mixture was heated to reflux and reacted with a small amount of acetic acid. After the reaction, water was added to precipitate crystals. Thereafter, the precipitate was filtered, washed with n-hexane, and purified by recrystallization using acetonitrile to obtain 4.6 parts by weight of pale yellow crystals (yield: 81%). Elemental analysis is as follows. Example 1 The exposure amount E1/2 (lux
-sec), and 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 compound [5], [8],

Photoreceptors using each of [9] were produced. V was applied to the thus obtained photoreceptor in the same manner as in Example 1. ,E,/, ,DDR, was measured. Example 5 0.45 parts of Hisazo compound [B] represented by the following - Monana CB), Borisdylene resin (molecular weight, +0000)
0.45 parts were dispersed in a Sandgrinder together with 50 parts of cycloquinanone. The obtained hisazo compound dispersion was dispersed using a sand glider 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 cyclohexanone. The obtained dispersion of the hisazo compound was applied onto a 100 μm thick aluminized mylar using a film applicator to give a dry film thickness of 0.3 g/m, and then dried. A hydrazone compound [:4:170 parts] and a polycarbonate resin (
A solution prepared by dissolving 70 parts of K-1,300 (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, an electrophotographic photoreceptor having a two-layer photosensitive layer was obtained. The photoreceptor thus obtained was used as a commercially available electrophotographic copy m (EP).
-470Z; manufactured by Minolta Camera Co., Ltd.) and corona charged at 6 KV to obtain an initial surface potential of V. (V), dry film thickness is 0.3 using a film applicator on chemically coated mylar.
It was coated at a concentration of g/m2 and then dried. A hydrazone compound (10
A solution prepared by dissolving 170 parts of polyarylate resin (Uioo, manufactured by Unitika) in 400 parts of 1.4 dioxane was applied to a total dry film thickness of 16 μm to form a charge generation layer. In this manner, an electrophotographic photoreceptor having a two-layer photosensitive layer was produced. Bar Examples 6 to 8 Same structure as in Example 5, except that the hydrazone compounds used in Example 5 (hydrazone compounds [11], [12], and [13] were used instead of lo'3) A photoreceptor to be used was prepared. Regarding the thus obtained photoreceptor, ■. 0.2 part was dissolved in 500 parts of 98% concentrated sulfuric acid with thorough stirring, and this was poured into 5000 parts of water to precipitate a photoconductive material composition of copper phthalocyanine and tetranitrocopper phthalonanine, followed by filtration and washing with water. , and dried at 120°C under reduced pressure. 10 parts of the photoconductive composition thus obtained was mixed with a thermosetting acrylic resin (Acridik, 105; manufactured by Dainippon Ink Co., Ltd.).
225 parts, melamine resin (Super Beckamine J820;
7.5 parts (manufactured by Inu H Hon Ink Co., Ltd.) and 15 parts of the above-mentioned hydrazone compound [:14] were placed in a ball mill bottle 1 to 1 with 100 parts of a mixed solvent containing equal amounts of methyl ethyl ketone and xylene, dispersed for 48 hours, and exposed to light. A photoreceptor was prepared by preparing a photosensitive coating liquid, applying the coating liquid onto an aluminum substrate, and drying to form a photosensitive layer having a thickness of about 15 μm. The photoreceptor thus obtained was corona charged in the same manner as in Example 1, except that the voltage was +6 KV. ,E1/
2. DDR+ was measured. Examples 10 to 12 Same structure as in Example 9, except that hydrazone compounds [15], [I6], [l] used in Example 9 were used instead of hydrazone compound [14]. Regarding the photoreceptor, the same method as in Example 9 was carried out. , E1/2
, DDR, was measured. Comparative Examples 5 to 8 Same structure as in Example 9, except that the following hydrazone compounds [G], [I]], [I], A photoreceptor was produced in exactly the same manner as in Example 1 except that [J] was used. 7] were prepared. With respect to the thus obtained photoreceptor, V was treated in the same manner as in Example 9. , E1/2, and DDR. Comparative Examples 1 to 4 Same structure as in Example 9, except that the following compounds [C], [D], [E], (F) were used instead of the hydrazone compound [14] 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 treated in the same manner as in Example 9. ,E,/2,DDR, was measured. V of the photoreceptors obtained in Examples 1 to 12 and Comparative Examples 1 to 8. , E1/2, and DDR are summarized in Table 1. Table I Table 1 (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 usable as a photoreceptor. It is small and has excellent sensitivity. Furthermore, a repeated actual photocopying test was conducted using a commercially available electrophotographic copying machine (EP-350Z; manufactured by Minolta Camera Co., Ltd.) during positive charging on the photoreceptor of Example 9. 3. Photoconductive material 4. Photosensitive layer 5. Charge transport layer 6. Charge generation layer 7. Surface protective layer 8. Intermediate layer Patent applicant Minolta Camera Co., Ltd. Representative Patent attorney Mt. It can be seen that in the final image of 16 Aohaga, a clear image with excellent gradation and no change in sensitivity was obtained, and the photoreceptor of the present invention also has stable repeatability. Effects of the Invention The present invention provides photoconductive compounds useful for 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;
R_3 represents a hydrogen atom, or an alkyl group, an aralkyl group, an aryl group, a fused polycyclic group, or a heterocyclic group, each of which may have a substituent; Ar_1 and Ar_2
independently has an alkyl group that may have a substituent, an aryl group that may have a substituent, a fused polycyclic group that may have a substituent, or a substituent. Ar_3 and Ar_4 independently represent a hydrogen atom, an alkyl group that may have a substituent, an aryl group that may have a substituent, and a heterocyclic group that may have a substituent. Indicates a fused polycyclic group that may have a substituent or a heterocyclic group that may have a substituent; except when Ar_3 and Ar_4 are both hydrogen atoms; Also, Ar_1 and Ar_2,
Ar_3 and Ar_4 may be combined to form a ring. ]