JPH01161245A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To improve sensitivity, potential stability, and surface strength by forming a layer containing a specified styrylbenzoxazole or styrylbenzothiazole derivative. CONSTITUTION:The photosensitive layer to be used has a functionally separated laminate structure composed of an electric charge generating layer and a charge transfer layer containing as a charge transfer material at least one of the styrylbenzoxazole or styrylbenzothiazole derivatives represented by formula I in which each of R1 and R2 is alkyl, hydrogen atom., aryl, aralkyl, or a heterocyclic group; each of R3-R5 and R7 is alkyl, aryl, aralkyl, or a heterocyclic group; R6 is H, alkyl, alkoxy, halogen, or nitro; Ar is an aryl or heterocyclic group; X is O or S; and n is 0 or 1, thus permitting each of sensitivity, potential stability, and durability to be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electrophotographic photoreceptors, and more particularly to electrophotographic photoreceptors having a low molecular weight organic photoconductor that provides improved electrophotographic properties.

[Prior Art] Inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide are conventionally known as photoconductive materials used in electrophotographic photoreceptors. These photoconductive materials offer numerous advantages,
For example, although it has advantages such as being able to be charged to an appropriate potential in a dark place, having little charge dissipation in a dark place, and being able to quickly dissipate a charge by being irradiated with light, it has various drawbacks. For example, with selenium-based photoreceptors, temperature, humidity,
Crystallization easily progresses due to factors such as pressure, and particularly when the ambient temperature exceeds 40° C., crystallization becomes significant, resulting in drawbacks such as a decrease in charging performance and the appearance of white spots on images. Cadmium sulfide photoreceptors do not provide stable sensitivity in humid environments, and zinc oxide photoreceptors require the sensitizing effect of sensitizing dyes such as rose bengal. It has the disadvantage that it cannot provide stable images over a long period of time because the dye deteriorates due to corona charging and photobleachs due to exposure light.

On the other hand, various organic photoconductive polymers including polyvinylcarbazole have been proposed, but although these polymers are superior to the above-mentioned inorganic photoconductive materials in terms of film formability and lightness, However, it has been difficult to put it into practical use to date because sufficient film forming properties have not yet been obtained, and it is still inferior to S-type photoconductive materials in terms of sensitivity, durability, and stability against environmental changes. It was because they were inferior. In addition, hydrazone compounds described in U.S. Pat. No. 4,150,987, triarylpyrazoline compounds disclosed in U.S. Pat.
Low-molecular organic photoconductors such as 9-styrylanthracene compounds described in Japanese Patent Laid-open No. 94828 and Japanese Patent Application Laid-Open No. 51-94829 have been proposed. By appropriately selecting the binder used, such low-molecular-weight organic photoconductors can overcome the drawbacks of film-forming properties that had been a problem in the field of organic photoconductive polymers. It cannot be said that the sensitivity is sufficient.

For this reason, in recent years, a laminated structure in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer has been proposed. An electrophotographic photoreceptor with this laminated structure as a photosensitive layer has 1. It has become possible to improve the sensitivity to visible light, charge retention, and surface strength.

Such an electrophotographic photoreceptor is disclosed in, for example, US Pat. No. 383
No. 7851, US Pat. No. 3,871,882, and the like.

However, electrophotographic photoreceptors that use conventional low-molecular organic photoconductors in the charge transport layer do not necessarily have sufficient sensitivity and characteristics, and especially when repeatedly charged and exposed, the bright area potential and dark area potential There are areas that need improvement.

[Problems to be Solved by the Invention] An object of the present invention is to provide an electrophotographic photoreceptor that eliminates the above-mentioned drawbacks or disadvantages, to provide a novel electrophotographic photoreceptor, and to provide a charge generation layer and a charge transport layer. The object of the present invention is to provide a novel charge transport material in a laminated photosensitive layer with functionally separated layers.

[Means for Solving the Problems, Effects] The present invention comprises an electrophotographic photoreceptor characterized by having a layer containing a styrylbenzoxazole or a styrylbenzthiazole compound represented by the following general formula.

In the general formula, R1 and R2 represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group which may have a substituent, and R1 and R2 may be the same or different. Further, R1 and R2 may jointly form a ring.

R3, R4 and R5 represent a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a heterocyclic group which may have a substituent, and R3, R4 and R5 may be the same or different.

R6 represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom or a nitro group.

R7 represents a hydrogen atom, an alkyl group that may have a substituent, an aryl group, an aralkyl group, or a heterocyclic group.

Ar represents an aryl group or a heterocyclic group which may have a substituent.

Also R7. Ar may also form a ring together.

X represents an oxygen atom or a sulfur atom.

n represents an integer of O or 1.

Specifically, R1 and R2 are methyl, ethyl,
Examples include groups such as propyl, butyl, phenyl, naphthyl, benzyl, phenethyl, naphthylmethyl, furyl, thionyl, benzothionyl, pyridyl, and quinoyl, and substituents for the above groups include fluorine atom, chlorine atom, bromine atom, and iodine atom. Examples include halogen atoms such as, alkyl groups such as methyl, ethyl, propyl, and butyl, alkoxy groups such as methoxy, ethoxy, propoxy, and phenoxy, nitro groups, cyan groups, and substituted amino groups such as morpholino and piperidino.

Further, a 5- to 7-membered ring may be formed together with the nitrogen atoms substituted by R1 and R2.

Examples of R3, R4 and R5 include groups such as methyl, ethyl, propyl, butyl, phenyl, naphthyl, benzyl, phenethyl, naphthylmethyl, furyl, thionyl, benzothionyl, pyridyl, and quinoyl, and substituents for the above groups include Fluorine atoms, chlorine atoms 4, halogen atoms such as bromine atoms, iodine atoms, alkyl groups such as methyl, ethyl, propyl, butyl, alkoxy groups such as methoxy, ethoxy, propoxy, phenoxy, nitro groups, cyano groups, morpholino, piperidino Examples include substituted amine 7 groups such as.

Examples of R6 include methyl, ethyl, propyl, butyl, methoxy, ethoxy, propoxy, phenoxy, fluorine atom, chlorine atom, bromine atom, and iodine atom.

Examples of R7 include groups such as ethyl, propyl, butyl, phenyl, naphthyl, benzyl, phenethyl, naphthylmethyl, furyl, thionyl, benzothionyl, pyridyl, and quinoyl, and substituents for the above groups include fluorine atom, chlorine atom, Halogen atoms such as bromine and iodine atoms, alkyl groups such as methyl, ethyl, propyl and butyl, alkoxy groups such as methoxy, ethoxy, propoxy and phenoxy, nitro groups, cyan groups, substituted amino groups such as morpholino and piperidino, etc. Can be mentioned.

Examples of Ar include groups such as phenyl, naphthyl, pyridyl, and quinoyl, and substituents for the above groups include halogen atoms such as fluorine atom, chlorine atom, bromine atom, and iodine atom, and alkyl atoms such as methyl, ethyl, propyl, and butyl. Examples include alkoxy groups such as methoxy, ethoxy, propoxy, and phenoxy; nitro groups; cyano groups; and substituted amino groups such as morpholino and piperidino.

Further, R7 and Ar may form a 5- to 7-membered ring together with the carbon atom to which they are bonded.

Representative examples of the styrylbenzoxazole or styrylbenzthiazole compound represented by the general formula are listed below.

Exemplified Compound (1) Exemplified Compound (2) Exemplified Compound (3) Exemplified Compound (4) Exemplified Compound (5) Exemplified Compound (6) Exemplified Compound (7) Exemplified Compound (8) Exemplified Compound (9) Exemplified Compound (10) Exemplary Compound (11) Exemplified Compound (12) Exemplified Compound (13) Exemplified Compound (15) Exemplified Compound (16) H3 Exemplified Compound (17) Exemplified Compound (18) Exemplified Compound (19) Exemplified Compound (20) Exemplified Compound (21 ) Exemplified Compound (22) Exemplified Compound (23) Exemplified Compound (25) Exemplified Compound (26) Exemplified Compound (27) Exemplified Compound (28) Exemplified Compound (29) Exemplified Compound (30) Exemplified Compound (31) Exemplified Compound ( 32) Exemplified Compound (33) Exemplified Compound (34) Exemplified Compound (35) Exemplified Compound (36) To explain the synthesis method of the above Exemplified Compound (1), p
- Obtain acid chloride from nitrobenzoic acid using thionyl chloride, react this with 0-hydroxy-p-methylaniline to obtain an amide compound, then reduce the nitro group using iron chloride to form an amine, and then Dehydration and ring closure with acid gave a benzoxazole compound. Further, the Ullmann reaction was performed to diphenylate the amine and oxidize the methyl group to form an aldehyde. This and W of benzhydrido bromide
A Wittig reaction was carried out using an Ittig reagent to obtain the target compound. Yield 9.4% Exemplary compound (1): CJ9Hz+iION 4 element analysis value Theoretical value (%) Measured value (%) C86,6486,6
2 H5,225,24 N 5 , 18 5.15 In a preferred embodiment of the present invention, styryl represented by the above general formula is used as a charge transport material of an electrophotographic photoreceptor in which the photosensitive layer is functionally separated into a charge generation layer and a charge transport layer. Benzoxazole or styrylbenzthiazole compounds can be used.

The charge transport layer according to the present invention is preferably formed by applying a solution of the styrylbenzoxazole or styrylbenzthiazole compound represented by the above general formula and a binder dissolved in a suitable solvent and drying the solution. Examples of the binder used here include polyarylate, polysulfone, polyamide, acrylic resin, acrylonitrile resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, phenol resin, epoxy resin, polyester, alkyd resin, polycarbonate, polyurethane, or these. Copolymers containing two or more of the repeating units of the resin include, for example, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-male-in acid copolymer, and the like. In addition to such insulating polymers, organic photoconductive polymers such as polyvinylcarbazole, polyvinyl anthracene, and polyvinylpyrene can also be used. - The blending ratio of the binder and the styrylbenzoxazole or styrylbenzthiazole compound is preferably 10 to 500 parts by weight per 100 parts by weight of the binder.

The charge transport layer is electrically connected to the underlying charge generation layer, and has the function of receiving and taking charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. have. At this time, this charge transport layer may be laminated on the charge generation layer or may be laminated under the charge generation layer. but,
It is desirable that the charge transport layer is laminated on the charge generation layer. This charge transport layer cannot be made thicker than necessary because there is a limit to its ability to transport charge carriers. - 5 to 30 gn1 for boat fishing, preferred range is 15 to 30 gn1
It is 25#Lm.

The organic solvent used when forming such a charge transport layer is 1. The binder may vary depending on the type of binder used, and it is preferable to select one that does not dissolve the charge generation layer or underlying subbing layer. Specific organic solvents include methanol,
Alcohols such as ethanol and isopropanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, dichlorohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and sulfoxides such as dimethyl sulfoxide. , tetrahydrofuran, dioxane, ethers such as ethylene glycol monomethyl ether, methyl acetate,
Esters such as ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene, or aromatics such as benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating is done by dip coating method, spray coating method,
spinner coating method, bead coating method, Meyer bar coating method, blade coating method,
This can be carried out using a coating method such as a roller coating method or a curtain coating method.

For drying, it is preferable to dry to the touch at room temperature and then heat dry. Heat drying at a temperature of 30 to 200°C for 5 minutes or more
It can be carried out stationary or under ventilation for a period of 2 hours.

The charge transport layer in the present invention can contain various additives. Such additives include diphenyl,
Diphenyl chloride, 0-terphenyl, p-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, pentuphenone, chlorinated paraffin, dilaurylthiopropionate, 3,5-dinitrosalicylic acid , various fluorocarbons, and the like.

The charge generation layer used in the present invention includes an inorganic charge generation material such as selenium, selenium-tellurium, and amorphous silicon;
Pyrylium dye, thiapyrylium dye 1. Cationic dyes such as azulenium dyes, thiacyanine dyes, and quinocyanine dyes; polycyclic quinone pigments such as phthalochacon pigments, anthorone pigments, dibenzpyrenequinone pigments, and pyranthrone pigments; indigo pigments;
A separate vapor deposited layer or resin dispersion layer selected from organic charge generating substances such as quinacridone pigments and azo pigments can be used.

Among the charge-generating substances used in the present invention, there are a wide variety of azo pigments in particular, and it is difficult to specify their structures, but the structures of particularly effective azo pigments will be specifically described below.

The general formula of the azo pigment is as shown below, where the central skeleton is A, the coupler portion is Cp, and n=2 or 3.
Typical examples of A-(N=N-Cp)nA, A-11R ■ (R is a hydrogen atom, a methyl group) A-12 Yellow atom) (X is an oxygen atom, a sulfur atom) A-17 R, fecol group, etc.) 1@-co=N-N=cH+ thyl group, NO group) Representative specific examples of the above CP p-1 p-2 p-3 atom, methyl group, methoxy group)) p -4 p-5 (R is ethyl group, phenyl group) p-6 Cp-7 child, fluorine atom) Cp-8, and the like.

By combining these central skeletons A and couplers Cp as needed, an azo pigment serving as a charge-generating substance is formed.The charge-generating layer is made by dispersing the above-mentioned charge-generating substance in a suitable binder and spreading it on a substrate. It can be formed by coating, or it can be formed by forming a vapor-deposited film using a vacuum evaporation device.

The binder that can be used when forming the charge generation layer by coating can be selected from a wide range of insulating resins, and poly-N
- Can be selected from organic photoconductive polymers such as vinylcarbazole, polyvinylanthracene and polyvinylpyrene. Preferably polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, urethane resin, casein The amount of resin contained in the 1° charge generation layer is preferably 80% by weight or less, preferably 40% by weight or less.

Examples of organic solvents used during coating include alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and amides such as N,N-dimethylpho2flumamide and N,N-dimethylacetamide. sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, and fats such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, and trichloroethylene. Group halogenated hydrocarbons or benzene,
Aromatics such as toluene, xylene, ligroin, monochlorobenzene, dichlorobenzene, etc. can be used.

Coating is done by dip coating method, spray coating method,
spinner coating method, bead coating method, Meyer bar coating method, plate coating method,
This can be carried out using a coating method such as a roller coating method or a curtain coating method.

The charge generation layer contains as much of the organic photoconductor as possible to obtain sufficient absorbance and is a thin film layer, for example 5 μm, in order to shorten the range of the generated charge carriers.
Hereinafter, it is preferable to use a thin film layer having a thickness of 0101 to Igm. This means that most of the incident light is absorbed by the charge generation layer, generating many charge carriers, and that the generated charge carriers must be injected into the charge transport layer without being deactivated by recombination or trapping. It is caused by something.

The photosensitive layer has a laminated structure of a charge generation layer and a charge transport layer.
Provided on a conductive support. As the conductive support, the support itself has conductivity, for example, aluminum,
Aluminum alloy, copper, zinc, stainless steel, vanadium, molybdenum, chromium, titanium, nickel, indium, gold and platinum can be used, and in addition, aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-tin oxide alloy Plastics (e.g., polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, acrylic resin, polyfluoroethylene, etc.), conductive particles (e.g., aluminum powder, titanium oxide, tin oxide, A support in which plastic or the above-mentioned conductive support is coated with zinc oxide, carbon black, silver particles, etc.) together with a suitable binder, a support in which plastic or paper is impregnated with conductive particles, or a conductive polymer. Plastic etc. can be used.

A subbing layer having barrier and adhesive functions may also be provided between the conductive support and the photosensitive layer.

The subbing layer is made of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, (nylon 6, nylon 6, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc. Can be formed.

The thickness of the subbing layer is 0.1 to 5 ILm, preferably 0.5
~3pm is appropriate.

When using a photoreceptor in which a conductive support, a charge generation layer, and a charge transport layer are laminated in this order, the styrylbenzoxazole or styrylbenzthiazole compound represented by the general formula used in the present invention has hole transport properties, so that the charge It is necessary to charge the surface of the transport layer negatively, and when exposed to light after charging, holes generated in the charge generation layer are injected into the charge transport layer in the exposed area, and then reach the surface, neutralize the negative charge, and lower the surface potential. Attenuation occurs and electrostatic contrast occurs between the exposed area and the unexposed area. It is necessary to use positively charged toner during development.

In another embodiment of the present invention, the azo pigments described above or those described in U.S. Pat.
No. 3,586,500, etc., photoconductive pigments and dyes such as pyrylium dyes, thiapyrylium dyes, selenapyrylium dyes, benzopyrylium dyes, benzothiapyryllium dyes, and naphtopyrylium dyes are used. It can also be used as a sensitizer.

In another embodiment, a eutectic complex of a pyrylium dye and an electrically insulating polymer having an alkylidene diarylene moiety as disclosed in U.S. Pat. No. 3,684,502 may be used as a sensitizer. This eutectic complex is, for example, 4-[
4-bis-(2-lyloloethyl)aminophenyl] -
2,6-cyphenylthiapyrylium perchlorate and poly(4゜4゛-isopropylidene diphenylene carbonate) are mixed in a halogenated hydrocarbon solvent (e.g. dichloromethane, chloroform, carbon tetrachloride, 1,1-dichloroethane, 1, 2-dichloroethane, 1゜1.2-1 dichloroethane, chlorobenzene, fromobenzene, 1,2-
dichlorobenzene) and then dissolved in a non-polar solvent (dichlorobenzene).
For example, by adding hexane, octane, decane, 2,2,4-trimethylbenzene, ligroin) as a particulate eutectic complex.

The electrophotographic photoreceptor in this specific example includes styrene-butadiene copolymer, silicone resin, vinyl resin, vinylidene chloride-acrylonitrile copolymer, styrene-acrylonitrile copolymer, vinyl acetate-vinyl chloride copolymer, polyvinyl butyral, polymethyl methacrylate, poly- N-butyl methacrylate,
Polyesters, cellulose esters, etc. can be contained as a binder.

The electrophotographic photoreceptor of the present invention can be used not only for electrophotographic copying machines, but also for laser printers, CRT printers,
It is also widely used in electrophotographic application fields such as electrophotographic plate making systems.

The electrophotographic photoreceptor of the present invention has the advantage of high sensitivity and small fluctuations in bright area potential and dark area potential when repeatedly charged and exposed.

[Example] Example 1 β-type copper phthalocyanine (trade name: LionolBlue)
NCB Toner manufactured by Toyo Ink Water Co., Ltd. 7 g of pigment purified by filtration after sequential reflux in ethanol and benzene, 14 g of Polyester Adhesive 49,000 (solid content 20%) manufactured by DuPont, 35 g of toluene A coating liquid was prepared by mixing 35 g of dioxane and dispersing the mixture in a ball mill for 6 hours.

This coating solution was applied to an aluminum sheet with a dry film thickness of 0.5
A charge generation layer was formed by coating with a Mayer bar so as to have gm.

Next, a solution obtained by stirring and dissolving 7 g of the above-mentioned exemplified compound (1) as a charge transport substance and 7 g of polycarbonate (trade name Panlite -1300, manufactured by Banjin Kasei) in a mixed solvent of 35 g of tetrahydrofuran and 35 g of chlorobenzene. was coated on the above charge generation layer using Mayer Par to provide a charge transport layer having a dry film thickness of 207 Zm, thereby producing an electrophotographic photoreceptor having a photosensitive layer consisting of two am.

This electrophotographic photoreceptor was corona-charged at 15 KV using an electrostatic copying paper tester Model-3P-428 manufactured by Kawaguchi Denki ■, held in a dark place for 1 second, and then exposed to an illuminance of 5 lux to be charged. Characteristics were measured.

As for charging characteristics, the surface potential (Vo) and the exposure amount (E 1/2) required to attenuate the potential (vl) to 1/2 when dark decayed for 1 second were measured.

Furthermore, in order to measure the fluctuations in bright area potential and dark area potential during repeated use, we used Canon's electrophotographic photoreceptor as described above.
NP-150Z, a PPC copier (product name: NP-150Z), and made 50,000 copies using the same machine.
) and dark potential (VD) were measured.

Comparative sample 1 was also prepared in exactly the same manner using a compound having the following structural formula in place of the exemplary compound (1), and its properties were measured in the same manner.

Japanese Unexamined Patent Publication No. 60-93445 Show the results.

V -V V -V El/2 lux sec
Example 1 690 680 1.9 Comparative Example 1 700 665 3.6 Initial After 50,000 sheets durability Example I VD(-V) 690 670VL(-V
) 130 160 Comparative Example I Vn(-V)700 600VL(-V
) 140. 230 From the above results, the electrophotographic photoreceptor of the present invention is superior to the comparative sample in both sensitivity and potential stability during long-term use.

Examples 2 to 14 Exemplary compounds (2
), (3), (5), (7), (9).

(14), (18), (23), (25), (27, (
31), (33), and (35), and the following pigment as a charge-generating substance, and in the same manner as in Example 1 except for Examples 2 to 1.
An electrophotographic photoreceptor corresponding to Example 4 was prepared, and its electrophotographic properties were measured in the same manner.

The results are shown below 6 2 1) 695 690 1.7'3 (
3) 700 690 1.24 (5)
695 675 2.85 (
7) 705 890 3.46
(9) 700 670 1.97
(14) 700 680 2.08
(18) 690 665 1.9
9 (23) 700 690 2.
010 (25) 705 680
3.611 (27) 695 67
0 2.812 (31) 700
665 1.713 (33) 695
685 3.714 (35) 6
95 690 2.3 Early 50,000 pieces After 3 695 135 690 14.5 Example 1
5 Coat an aqueous solution of casein in ammonia (11.2 g of casein, 1 g of 28% ammonia water, 222 mJ1 of water) on an aluminum cylinder using a dip coating method, and dry to form a subbing layer with a coating amount of 1.0 g/m2. did.

1 part by weight of butyral resin (trade name: Kosuretsuku BM-2, manufactured by Tsukushiki Chemical Co., Ltd.) and 30 parts by weight of isopropyl alcohol were dispersed for 4 hours using a ball mill disperser. This dispersion was applied onto the previous subbing layer by a dip coating method and dried to form a charge generating layer. The film thickness was 0.3 pm.

Next, 1 part by weight of the charge transport substance of Exemplary Compound (2), polysulfone (trade name P1700, Union Carbide Co., Ltd.)
1 part by weight and 6 parts by weight of monochlorobenzene were mixed and dissolved by stirring with a stirrer.

This liquid was applied onto the charge generation layer by dip coating and dried to form a charge transport layer. The film thickness at this time is 1
It was 2ILm.

A corona discharge of 15 KV was applied to the photoreceptor thus prepared.

The surface potential (initial potential Vo) at this time was measured. Furthermore, the surface potential of this photoreceptor was measured after it was left in a dark place for 5 seconds (attenuation).

Sensitivity was evaluated by measuring the exposure amount (E 1/2 ILJ /cm 2 ) required to attenuate the potential vK to 172 after dark decay. At this time, a gallium/aluminum/propylene ternary semiconductor laser (oscillation wavelength: 780 nm) was used as a light source. Show the results.

Vony 690V El/2: 1.9 pLJ/cm2 Next, this photoconductor was transferred to a laser beam printer (product name: LBP-CX, manufactured by Canon ■), which is a reversal development type electrophotographic printer equipped with the same semiconductor laser as above. An actual image forming test was conducted by setting the photoreceptor in place of the photoreceptor.

The conditions are as follows.

Surface potential knee after primary charging 700V, surface potential knee 150V after image exposure, transfer potential: +700V, developer polarity:
Negative polarity, process speed: 50mm/sec, development conditions (development bias) knee 450V, image exposure scan method: image scan, - exposure before next charging: 50mm ux
, see were exposed to red over the entire surface and image formation was performed by line scanning a laser beam in accordance with character and image signals, and good prints were obtained for both characters and images.

Example 16 3 g of 4-(4-dimethylaminophenyl)-2,6-cyphenylthiapyrylium perchlorate and 5 g of the above-mentioned exemplified compound (7) were added to a toluene solution of polyester (Polyester Adhesive 49000, manufactured by DuPont). The mixture was mixed with 100 mJl of dioxane (50:50) solution and dispersed in a ball mill for 6 hours. The film thickness after drying this dispersion was 15
It was applied onto an aluminum sheet using a Mayer bar so that the amount was 1 Lm.

The electrophotographic properties of the photoreceptor thus prepared were measured in the same manner as in Example 1. The results are shown below.

Vo knee 700V, Vl knee 695VEl/2:
2.4uux, sec Initial VD Knee 695V, VL Knee 145V After 50,000 sheets durability VD Knee 680V, VL Knee 165V Example 17 An ammonia aqueous solution of casein (described above) was applied on an aluminum plate using a Mayer bar and dried, and the film thickness was formed an adhesive layer of Igm.

Next, after dispersing 5 g of a disazo pigment with the following structure and 2 g of butyral resin (degree of butyralization 63 mol%) in 95 mfl of ethanol,
A charge generation layer was formed by coating on the adhesive layer to have a thickness of 0.4 JLm after drying.

Next, 5 g of the exemplified compound (34) and poly-4,4'
-Dioxydiphenyl-2,2-propane carbonate (viscosity average molecular weight 30,000) 5g in dichloromethane 150ml
A solution dissolved in Jlj was applied onto the charge generation layer and dried to form a charge transport layer with a film thickness of 11 m to produce an electrophotographic photoreceptor.

The electrophotographic properties of this electrophotographic photoreceptor were measured in the same manner as in Example 1. Show the results. -Vo knee 700
V Vl Knee 690V El/2: 2.3uux, see Initial After 50,000 sheets durability Vo Knee 690V Vo Knee 670VV L
: -140V V L : -165V Example 18 A 0.2 mm thick molybdenum plate (support) whose surface was cleaned was fixed at a predetermined position in a glow discharge deposition tank. Next, the inside of the tank was evacuated to a degree of vacuum of about 5×10 6 torr.

Thereafter, the input voltage of the heater was increased to stabilize the temperature of the molybdenum support at 150°C. After that, hydrogen gas and silane gas (15% by volume relative to hydrogen gas) were introduced into the tank.
Adjust the gas flow rate and main valve of the deposition tank to 0.5 tor.
stabilized at r.

Next, a high frequency power of 5 MHz was applied to the induction coil to generate a glow discharge inside the coil in the tank, resulting in an input power of 30 W. After growing an amorphous silicon film on the support under the above conditions and maintaining the same conditions until the film thickness reached 2 pm, glow discharge was discontinued. After that, the heating heater and high frequency power supply are turned off, and after waiting for the support temperature to reach 100°C, the hydrogen gas and silane gas outflow valves are closed. It was returned and the support was taken out.

Next, a charge transport layer was formed on this amorphous silicon layer in the same manner as in Example 1 except that exemplified compound (16) was used as a charge transport substance.

The photoreceptor obtained in this way was installed in a charging exposure experimental device,
It was corona charged at -6 KV and immediately irradiated with a light image. The light image was illuminated through a transmission type test chart using a tungsten lamp light source.

Thereafter, a positively charged developer (containing toner and carrier) was cascaded onto the surface of the photoreceptor to obtain a good toner image on the surface of the photoreceptor.

Example 19 3 g of 4-(4-dimethylaminophenyl)-2,6-diphenylthiapyrylium verchlorate and poly(4,
4”-isopropylidene diphenylene carbonate) 3
After sufficiently dissolving g in 200 ml of dichloromethane,
100 mM of toluene was added to precipitate the eutectic complex. After filtering this precipitate, dichloromethane was added to redissolve it, and then 100 mfL of n-hexane was added to this solution to obtain a precipitate of a eutectic complex.

5 g of this eutectic complex was added to 95 mu of a methanol solution containing 2 g of polyvinyl butyral and dispersed in a ball mill for 6 hours. After drying, this dispersion was applied onto an aluminum plate having a casein layer using a Mayer bar to a film thickness of 0.41 Lm to form a charge generation layer.

Next, a cover layer of a charge transport layer was formed on this charge generation layer in the same manner as in Example 1 except that exemplified compound (18) was used.

The electrophotographic properties of the photoreceptor thus prepared were measured in the same manner as in Example 1.

Show the results.

Vonny 695V, V1 knee 685V El/2: 3.41jux, see Initial VD knee 690V, VL knee 145V after 50,000 sheets durability V D: -660V, V L: -195V Example 20 Common used in Example 19 5 g of the same crystal complex and 5 g of the exemplified compound (25) were added to a 150 mM solution of polyester (described above) in tetrahydrofuran and thoroughly mixed and stirred.

This liquid was applied onto an aluminum sheet using a Mayer bar so that the film thickness after drying was 15 pLm.

The electrophotographic properties of this photoreceptor were determined in the same manner as in Example 1. Show the results.

Vony 700V, V1 knee 690V El/2: 2.5 Mux, see Initial VD knee 690V, VL knee 140V After 50,000 sheets running v,, knee 675V, VL knee 150V [Effect of the invention] Electrophotographic photosensitive of the present invention By using a specific styrylbenzoxazole or styrylbenzthiazole compound as a charge transport material, the material has remarkable effects of high sensitivity, potential stability, high durability, and can be applied to a wide range of electrophotographic fields. It is something.

Claims (1)

[Claims] (1) An electrophotographic photoreceptor characterized by having a layer containing a styrylbenzoxazole or a styrylbenzthiazole compound represented by the following general formula. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ In the formula, R_1 and R_2 represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group that may have a substituent, and R_1 and R_2 are the same. may also be different. Further, R_1 and R_2 may jointly form a ring. R_3, R_4 and R_5 represent a hydrogen atom, an alkyl group which may have a substituent, an aryl group, an aralkyl group or a heterocyclic group, and R_3, R_4 and R_5 may be the same or different. R_6 represents a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, or a nitro group. R_7 is a hydrogen atom, an alkyl group that may have a substituent,
Indicates an aryl group, an aralkyl group, or a heterocyclic group. Ar represents an aryl group or a heterocyclic group which may have a substituent. Further, R_7 and Ar may jointly form a ring. X represents an oxygen atom or a sulfur atom. n represents an integer of 0 or 1.