JPH04225365A - Photosensitive body - Google Patents

Abstract

PURPOSE:To obtain a photosensitive body having superior characteristics with respect to sensitivity, electric charge transferring property, initial surface potential, the rate of dark attenuation, etc., by forming a photosensitive layer contg. a specified aminobiphenyl compd. CONSTITUTION:When a photosensitive layer 4 contg. a photoconductive material 3 and an electric charge transferring material 2 blended with a binder is formed on a substrate 1 to obtain a photosensitive body, an aminobiphenyl compd. represented by formula I is used as the electric charge transferring material 2. In the formula I, R1 is H or aryl which may have a substituent, each of R2-R8 is H, alkyl which may have a substituent, alkoxy, etc., and X is O or S. The aminobiphenyl compd. has high compatibility with the binder and hardly undergoes a change in the sensitivity in case of repeated use because plural rings are present in the molecule.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoreceptor having a photosensitive layer containing a novel aminobiphenyl compound.

0002

[Prior Art] Generally, 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 transferred as it is. A direct method that obtains a copy image by fixing it on a photoreceptor, a powder image transfer method or a photosensitive method that transfers the visible image on the photoreceptor onto a transfer material such as paper and fixes the transferred image to obtain a copy image. 2. Description of the Related Art A latent image transfer method is known in which an electrostatic latent image on a body is transferred onto a transfer paper, and the electrostatic latent image on the transfer paper is developed and fixed.

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. Although these photoconductive materials have many advantages, such as less charge dissipation in the dark or the ability to rapidly dissipate charge when exposed to light, they also have various disadvantages. . For example, selenium-based photoreceptors require difficult manufacturing conditions, high manufacturing costs, and must be handled with care because they are 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;
These polymers, compared to the above-mentioned inorganic photoconductive materials,
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.

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. In such functionally separated type photoreceptors, many organic compounds have been mentioned as charge transport materials used in the charge transport layer, but in practice they have various problems.

For example, 2,5-bis(p-diethylaminophenyl) 1,3,4-oxadiazole described in US Pat. No. 3,189,447 has low compatibility with binders and forms crystals. Easy to precipitate. Japanese Patent Publication No. 2-17
The following compounds described in Publication No. 8668 have good compatibility with binders, but cannot be used repeatedly.

[Chemical formula 2] When this occurs, a change in sensitivity occurs. JP 1-118141
The following compounds described in the publication have low compatibility with binders and tend to precipitate crystals.

##STR00003## Further, the hydrazone compound described in JP-A-54-59143 has relatively good residual potential characteristics, but has the disadvantage of poor charging ability and repeatability. The reality is that there are almost no low-molecular-weight organic compounds that have practically desirable properties for producing photoreceptors.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photoreceptor that overcomes the various drawbacks of the conventional photoreceptors mentioned above. Another object of the present invention is to provide a novel photoreceptor that is easy to manufacture, relatively inexpensive, and has excellent durability.

[0008]

[Means for Solving the Problems] The present invention relates to a photoreceptor having a photosensitive layer containing an aminobiphenyl compound represented by the above general formula [I] (Chemical formula 1) on a conductive support. The aminobiphenyl compound represented by the general formula [I] has high compatibility with binders, and since it has a heterocycle in the molecule, there is little change in sensitivity when used repeatedly, and it satisfies the conditions required in electrophotography. To provide a satisfactory photoreceptor.

In the present invention, the aminobiphenyl compound represented by the general formula [I] (Chemical formula 1) contained in the photosensitive layer can be, for example, a halogen biphenyl derivative represented by the following general formula [II] (Chemical formula 4) and the following general formula Formula [III]
It is produced by reacting a diphenylamine derivative represented by (Chemical formula 5).

[In the formula, R1, R2, R3, R4, and X are the same as above]

[In the formula, R5, R6, R7, and R8 are the same as above]
Preferred specific examples of the aminobiphenyl compound represented by the general formula [I] (Chemical formula 1) of the present invention include those having the following structural formula, but are not limited thereto.

0010

[C6]

[C7]

[Chemical formula 8]

The photoreceptor of the present invention contains one or two aminobiphenyl compounds represented by the general formula [I] (Chemical formula 1).
It has a photosensitive layer containing more than one species. 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 photosensitive layer formed by dispersing a charge-generating material and an aminobiphenyl 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 are also so-called laminated photoreceptors in which a charge transport layer is provided thereon. Although the aminobiphenyl 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 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. Bye. The thickness of the photosensitive layer at this time is 3~
The thickness is preferably 30 μm, preferably 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 charging property will be poor and the mechanical strength of the photosensitive layer will be weakened. The amount ranges from 0.01 to 3 parts by weight, preferably from 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 an amine and applied, or the pigment is coated with a suitable solvent or a binder if necessary. It is obtained by applying and drying a coating liquid prepared by dispersing a resin in a solution, and then applying and drying a solution containing a charge transporting 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 thickness of the charge transport layer is 3 μm or less.
~30 μm, preferably 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 1.3 parts by weight, per 1 part by weight of the binder resin.
Parts by weight.

In addition to the binder resin, the photoreceptor of the present invention contains plasticizers such as halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, dibutyl phthalate, and 0-terphenyl, as well as chloranil, tetracyanoethylene, and 0-terphenyl.
, 4,7-trinitrofluorenone, 5,6-dicyanobenzoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride, 3,5-dinitrobenzoic acid and other electron-withdrawing sensitizers, methyl violet, rhodamine B, cyanine Sensitizers such as dyes, pyrylium salts, thiapyrylium salts, etc. may also be used. In addition, antioxidants and ultraviolet absorbers,
Dispersion aids, anti-settling agents, etc. may also be used as appropriate.

The electrically insulating binder resin used in the present invention includes electrically insulating binders such as thermoplastic resins, thermosetting resins, photocurable resins, and photoconductive resins, 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 (
thermoplastic resins such as ionomers), styrene-butadiene block copolymers, polycarbonates, vinyl chloride-vinyl acetate copolymers, cellulose esters, polyimides, and styrene resins; epoxy resins, urethane resins, silicone resins, phenolic resins, melamine resins, These include thermosetting resins such as xylene resins, alkyd resins, and thermosetting acrylic resins; photocurable resins; photoconductive resins such as polyvinylcarbazole, polyvinylpyrene, polyvinylanthracene, and polyvinylpyrrole. These can be used alone or in combination. It is desirable that these electrically insulating resins have a volume resistivity of 1×10 12 Ω·cm or more when measured alone.

As the charge generating material, bisazo pigments,
Triarylmethane dyes, thiazine dyes, oxazine dyes, xanthene dyes, cyanine dyes, styryl dyes, pyrylium dyes, azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone dyes Organic substances such as pigments, bisbenzimidazole pigments, indathrone pigments, squalium salt pigments, azulene pigments, and phthalocyanine pigments, selenium,
Examples include inorganic substances such as tellurium, selenium alloys such as selenium and arsenic, 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. , or these metals are vacuum-deposited or electrolessly plated onto a plastic film, etc., or a layer of a conductive compound such as a conductive polymer, indium oxide, or tin oxide is coated on a support such as paper or a plastic film. Alternatively, one provided by vapor deposition is used.

Examples of the structure of a photoreceptor using the aminobiphenyl compound of the present invention are schematically shown in FIGS. 1 to 5. Figure 1 shows a photoconductive material (3) and a charge transport material (
This is a photoreceptor in which a photosensitive layer (4) containing 2) as a binder is formed, and the aminobiphenyl compound of the present invention is used as a charge transport material. Note that the symbols 2 and 3 in FIGS. 2 to 5 below have the same meanings as above. FIG. 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). There is. Charge transport layer (5
) contains the aminobiphenyl compound of the present invention. FIG. 3 shows a functionally separated photoreceptor having a charge generation layer (6) and a charge transport layer (5) as in FIG. 2, but contrary to FIG. A generation layer (6) is formed.

FIG. 4 shows the photoreceptor shown in FIG. 1 further provided with a surface protective layer (7) on its surface, and the photosensitive layer (4) has a charge generation layer (6) and a charge transport layer (5). It may also be a functionally separated photoreceptor having the following functions. Materials used for the surface protective layer include polymers such as acrylic resin, polyaryl resin, polycarbonate resin, and urethane resin.
Alternatively, a material in which a low resistance compound such as tin oxide or indium oxide is dispersed is suitable. Figure 5 shows the base (1)
An intermediate layer (8) is provided between the photosensitive layer (4) and the photosensitive layer (4). It can be provided to improve injectability.

Materials used for the intermediate layer include polymers such as polyimide, polyamide, nitrocellulose, polyvinyl butyral, and polyvinyl alcohol as they are, or those in which low-resistance compounds such as tin oxide and indium oxide are dispersed, aluminum oxide, Vapor deposited films of zinc oxide, silicon oxide, etc. are suitable. Further, the thickness of the intermediate layer is preferably 1 μm or less.

(Synthesis example) Iodobiphenyl compound represented by the following formula [IV] (Chemical formula 9)

embedded image 10.0 parts by weight, 5.5 parts by weight of diphenylamine, 4.5 parts by weight of potassium carbonate, and 4.1 parts by weight were reacted by heating at 180-190° C. in 50 parts by weight of nitrobenzene. After the reaction, methanol was added to precipitate crystals. The precipitate was filtered, washed with methanol, and purified by column using silica gel to obtain 8.8 parts by weight of crystals represented by the following formula (1). Elemental analysis was as follows. C
(%) H (%) N (%)
Calculated value 70.78 5.02
6.39 Actual measurement value
70.11 5.10 6.21

[Chemical formula 10]

[0022]

EXAMPLES In the following examples, "parts" are parts by weight unless otherwise specified. (Example 1) Bisazo compound represented by the following general formula [A] (Chemical formula 11)

embedded image 0.45 parts of polyester resin (Vylon 200; manufactured by Toyobo Co., Ltd.) and 0.45 parts of polyester resin were dispersed together with 50 parts of cyclohexanone using a sand grinder. The obtained bisazo compound dispersion was applied onto a 100 μm thick aluminized mylar using a film applicator to give a dry film thickness of 0.
．． It was applied to a weight of 3 g/m2 and then dried. On the thus obtained charge generation layer, 70 parts of an aminobiphenyl compound (Chemical formula 6 (1)) and 70 parts of a polycarbonate resin (K-1300; manufactured by Teijin Chemicals) were dissolved in 400 parts of 1,4 dioxane. The dried solution has a dry film thickness of 16 μm.
A charge transport layer was formed. In this way, an electrophotographic photoreceptor having a two-layer photosensitive layer was obtained. The photoreceptor thus obtained was transferred to a commercially available electrophotographic copying machine (
-6K using EP-470Z; manufactured by Minolta Camera Co., Ltd.
The initial surface potential Vo (V) of the first and 1000th times of corona charging with V, the exposure amount E1/2 (lux ・sec) required to reduce the initial potential to 1/2, and when left in the dark for 1 second. The decay rate of the initial potential DDR1 (
%) was measured.

(Examples 2 to 4) Same method as in Example 1, except that the aminobiphenyl compound ((1) of Chemical Formula 6) used in Example 1 was replaced with an aminobiphenyl compound, A photoreceptor was produced using each of (2), (3), and (4) in Section 6. Regarding the photoreceptor thus obtained,
The 1st and 1000th Vo
, E1/2, and DDR1 were measured.

(Example 5) Bisazo compound represented by the following general formula [B]

[Chemical formula 12] 0.45 parts, polystyrene resin (molecular weight 40,000) 0
．． 45 parts were dispersed with 50 parts of cyclohexanone in a sand grinder. The resulting bisazo compound dispersion was applied onto a 100 μm thick aluminized Mylar using a film applicator to give a dry film thickness of 0.3 g/m2.
It was applied and dried. An aminobiphenyl compound (chemical formula 7) is placed on the charge generation layer thus obtained.
(10)) and polyarylate resin (U-1
00; manufactured by Unitika) 70 parts to 400 parts of 1,4 dioxane
A charge generation layer was formed by applying the solution dissolved in the sample to a dry film thickness of 16 μm. In this manner, an electrophotographic photoreceptor having a two-layer photosensitive layer was produced.

(Examples 6 to 8) Same method as in Example 5, but with the exception that the aminobiphenyl compound ((10) of Chemical Formula 7) used in Example 5 was replaced with an aminobiphenyl compound, Chemical Formula 7 (10). Photoreceptors using each of (11), (12), and (13) of No. 7 were prepared. Regarding the photoreceptor thus obtained, Vo, E1/2 and DDR1 were measured for the first and 1000th measurements in the same manner as in Example 1.

(Example 9) 50 parts of copper phthalocyanine and 0.2 parts of tetranitrocopper phthalocyanine were added to 5 parts of 98% concentrated sulfuric acid.
00 parts with sufficient stirring, and add 5000 parts of water.
After depositing a photoconductive material composition of copper phthalocyanine and tetranitrocopper phthalocyanine, it was filtered, washed with water, and dried at 120° C. under reduced pressure. 10 parts of the photoconductive composition thus obtained were mixed with 22.5 parts of a thermosetting acrylic resin (Acridik A405; manufactured by Dainippon Ink Co., Ltd.) and 7.5 parts of a melamine resin (Super Beckamine J820; manufactured by Dainippon Ink Co., Ltd.). , the above-mentioned aminobiphenyl compound (Chemical formula 7)
Put 15 parts of (14)) in a ball mill pot with 100 parts of a mixed solvent of equal amounts of methyl ethyl ketone and xylene and disperse for 48 hours to prepare a photosensitive coating liquid, and apply this coating liquid on an aluminum substrate. Approximately 1 thick when dry
A photoreceptor was prepared by forming a 5 μm photosensitive layer. Regarding the thus obtained photoreceptor, Vo, E1/2, and DDR1 were measured in the same manner as in Example 1, except that corona charging was performed at +6 KV, and the Vo, E1/2, and DDR1 were measured for the first and 1000th times.

(Examples 10 to 12) The same method as in Example 9 was carried out, except that the aminobiphenyl compound ((14) of Chemical Formula 7) used in Example 9 was replaced with an aminobiphenyl compound, Chemical Formula 7 (14). 7 (15), (16) and Chemical 8 (
17), photoreceptors were prepared using each of the following methods. Regarding the photoconductor thus obtained, Vo, E1/2, and DDR1 of the 1st and 1000th photoreceptor were measured in the same manner as in Example 9.
was measured.

(Comparative Examples 1 to 4) Same composition as in Example 9, except that the aminobiphenyl compound ((14) of Chemical Formula 7) used in Example 9 was replaced with the compound of Chemical Formula 13 below. A photoreceptor was produced in exactly the same manner as in Example 9 except that [C], [D], [E], and [F] were each used.

embedded image Vo , E1/2 and DDR1 of the thus obtained photoreceptor were measured in the same manner as in Example 9 for the first and 1000th measurements.

(Comparative Examples 5 to 8) Same method as in Example 9, except that the following aminobiphenyl compound ((14) in Chemical Formula 7) was used in place of the aminobiphenyl compound used in Example 9. A photoreceptor was produced in exactly the same manner as in Example 9 except that G], [H], [I], and [J] were each used.

embedded image Vo , E1/2 and DDR1 of the thus obtained photoreceptor were measured in the same manner as in Example 9 for the first and 1000th measurements. Examples 1 to 12, Comparative Examples 1 to
The 1st and 1000th Vo of the photoreceptor obtained in step 8,
The measurement results of E1/2 and DDR1 are summarized in Table 1.

[0030]

[Table 1] 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, the dark decay rate is small enough to be used as a photoreceptor, and the sensitivity is It is also excellent in

[0031]

The present invention provides a photoconductive compound useful for photoreceptors. The photoconductive compounds of the present invention are particularly useful as charge transport materials. The photoreceptor of the present invention having an aminobiphenyl compound having a benzothiazole or benzoxazole ring in the molecule has excellent photoreceptor properties such as sensitivity, charge transport properties, initial surface potential, and dark decay rate, and is free from optical fatigue due to repeated use. few.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the structure of a dispersed photoreceptor in which a photosensitive layer is laminated on a conductive support according to the present invention.

FIG. 2 is a schematic diagram of the structure of a functionally separated photoreceptor in which a charge generation layer and a charge transport layer are laminated on a conductive support according to the present invention.

[Figure 3] Schematic diagram of another embodiment of the same as above.

FIG. 4 is a schematic diagram of the structure of another embodiment of the dispersion type photoreceptor in which a photosensitive layer is laminated on a conductive support according to the present invention.

[Figure 5
】Schematic diagram of still another aspect of the same as above.

[Explanation of symbols]

1 Conductive support 2 Charge transport material 3 Photoconductive material 4 Photosensitive layer 5 Charge transport layer 6 Charge generation layer 7　Surface protective layer 8 Middle class

Claims (1)

[Claims] Claim 1: On a conductive support, the following general formula [I]
A photoreceptor having a photosensitive layer containing an aminobiphenyl compound represented by (Chemical formula 1). [Formula 1] [In the formula, R1 represents a hydrogen atom or an aryl group which may have a substituent, R2 , R3 , R4 , R5 ,
R6, R7, R8 are each independently a hydrogen atom,
Alkyl group, alkoxy group, which may have a substituent,
represents a thioalkoxy group, an aryloxy group, or a halogen atom, and X represents O or S]