JP2659076B2 - Photoconductor - Google Patents

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 triphenylamine compound.

[0002]

2. Description of the Related Art In general, in electrophotography, an electrostatic latent image is formed by charging and exposing the surface of a photosensitive layer of a photoreceptor, developing the latent image with a developer, visualizing the latent image, and directly converting the visible image as it is. A direct method of fixing a photoreceptor to obtain a copy image, a powder image transfer method of transferring a visible image on a photoreceptor onto a transfer material such as paper, and fixing the transferred image to obtain a copy image, or a photosensitive method. 2. Related Art A latent image transfer method of transferring an electrostatic latent image on a body onto transfer paper, and developing and fixing the electrostatic latent image on the transfer paper is known.

As a material constituting a photosensitive layer of a photosensitive member used in this type of electrophotography, inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have been conventionally known.

[0004] These photoconductive materials have many advantages, such as less charge dissipation in a dark place, or the ability to quickly dissipate charge by light irradiation, but have various disadvantages. have. For example, in the case of a selenium-based photoconductor, manufacturing conditions are difficult, the manufacturing cost is high, and the selenium-based photoconductor is susceptible to heat and mechanical shock. Cadmium sulfide photoreceptors and zinc oxide photoreceptors do not provide stable sensitivity in humid environments, and dyes added as sensitizers cause charge deterioration due to corona charging and photobleaching due to exposure, resulting in long-term However, there is a disadvantage that stable characteristics cannot be provided over a wide range.

On the other hand, various organic photoconductive polymers such as polyvinyl carbazole have been proposed.
These polymers, compared to the aforementioned inorganic photoconductive material,
Although excellent in film forming properties and lightness, it is still inferior to inorganic photoconductive materials in sufficient sensitivity, durability and stability due to environmental changes.

[0006] Low molecular weight organic photoconductive compounds are preferred in that the physical properties or electrophotographic properties of the coating can be controlled by selecting the type and composition ratio of the binder used in combination. Since it is used in combination with a binder, high compatibility with the binder is required.

A photoreceptor in which these high and low molecular weight organic photoconductive compounds are dispersed in a binder resin has drawbacks such as a large residual potential due to many carrier traps and low sensitivity. Therefore, it has been proposed to solve the above-mentioned drawbacks by blending a charge transport material with a photoconductive compound.

Further, a function-separated type photoreceptor has been proposed in which the charge generation function and the charge transport function of the photoconductive function are shared by different substances. In such a function-separated type photoreceptor, many organic compounds are mentioned as the charge transporting material used for the charge transporting layer, but there are various problems in practice.

For example, 2,5-bis (P-diethylaminophenyl) 1,3,4-oxadiazole described in US Pat. No. 3,189,447 has low compatibility with a binder and a crystal. Easy to precipitate. JP-A-2-17
The following compound described in No. 8668 is

Embedded image Although the compatibility with the binder is good, the sensitivity changes when repeatedly used.

The following compound described in JP-A-1-118141 is

Embedded image The compatibility with the binder is low and crystals are likely to precipitate.

The hydrazone compound described in Japanese Patent Application Laid-Open No. 54-59143 has the disadvantage that the residual potential characteristics are relatively good, but the charging ability and the repetition characteristics are inferior. As described above, in reality, there is almost no low-molecular-weight organic compound having practically preferable characteristics in producing a photoreceptor.

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrophotographic photosensitive member which has solved the above-mentioned various disadvantages of the conventional photosensitive member. Another object of the present invention is to provide a novel photoreceptor which is easy to manufacture, relatively inexpensive and has excellent durability.

[0013]

The present invention relates to a photoreceptor having a photosensitive layer containing a triphenylamine compound represented by the above general formula [I] (formula 1) on a conductive support.
The triphenylamine compound represented by the general formula (I) has high compatibility with a binder, and has a coumarin skeleton in the molecule, so that the sensitivity change when used repeatedly is small and the conditions required in electrophotography are small. Is provided. In the present invention, the triphenylamine compound represented by the general formula [I] contained in the photosensitive layer is, for example, a 7-aminocoumarin derivative represented by the following general formula [II] (formula 4) and a general formula [III] ( It is produced by reacting an iodobenzene derivative represented by the following chemical formula 5).

[0014]

Embedded image [Wherein R ¹ , R ² and R ³ are the same as above]

[0015]

Embedded image [Wherein R ⁴ and R ⁵ are the same as above]

Preferred specific examples of the triphenylamine compound represented by the general formula [I] of the present invention include those having the following structural formulas (Chemical Formula 6), (Chemical Formula 7) and (Chemical Formula 8). However, the present invention is not limited to this.

[0017]

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[0018]

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[0019]

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The photoreceptor of the present invention has a photosensitive layer containing one or more triphenylamine compounds represented by the general formula [I]. Although various types of photoconductors are known, the photoconductor of the present invention may be any of those photoconductors. For example, a single-layer photoreceptor having a photosensitive layer formed by dispersing a charge generating material and a triphenylamine compound in a resin binder on a support, or a charge generating layer containing a charge generating material as a main component on a support may be used. And a so-called laminated photoreceptor provided with a charge transport layer thereon. Although the triphenylamine compound of the present invention is a photoconductive substance, it acts as a charge transport material and can transport a charge carrier generated by absorbing light extremely efficiently.

In order to manufacture a single-layer type photoreceptor, fine particles of a charge generating material are dispersed in a resin solution or a solution in which a charge transporting material and a resin are dissolved, and this is coated on a conductive support and dried. I just need. The thickness of the photosensitive layer at this time is 3 to
The thickness is 30 μm, preferably 5 to 20 μm. If the amount of the charge generating material used is too small, the sensitivity is poor, and if it is too large, the chargeability is deteriorated, the mechanical strength of the photosensitive layer is reduced, and the proportion in the photosensitive layer is 1 part by weight of the resin. On the other hand, the range is 0.01 to 3 parts by weight, preferably 0.2 to 2 parts by weight.

In order to produce a laminated photoreceptor, a charge generation material is vacuum-deposited on a conductive support, or is applied by dissolving in a solvent such as an amine, or a pigment is applied to a suitable solvent or a suitable solvent. If so, a coating solution prepared by dispersing in a solution in which a binder resin is dissolved is applied and dried, and then a solution containing a charge transport material and a binder is applied and dried thereon. At this time, the thickness of the charge generation layer was 4 μm.
m, preferably 2 μm or less, and the thickness of the charge transport layer is 3 to 30 μm, preferably 5 to 20 μm. The proportion 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.

The photoreceptor of the present invention comprises, together with a binder resin, a plasticizer such as halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, dibutylphthalate, 0-terphenyl, chloranil, tetracyanoethylene,
Electron withdrawing sensitizers such as 2,4,7-trinitrofluorenone, 5,6-dicyanobenzoquinone, tetracyanoquinodimethane, tetrachlorophthalic anhydride, 3,5-dinitrobenzoic acid, methyl violet, rhodamine B; Sensitizers such as cyanine dyes, pyrylium salts and thiapyrylium salts may be used.

Further, an antioxidant, an ultraviolet absorber, a dispersing aid, an anti-settling agent and the like may be appropriately used.

The electrically insulative binder resin used in the present invention is a known electrically insulative binder such as a thermoplastic resin or a thermosetting resin, a photocurable resin or a photoconductive resin. 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 blocks. Thermoplastic resins such as copolymer, polycarbonate, vinyl chloride-vinyl acetate copolymer, cellulose ester, polyimide, and styrene resin; epoxy resin, urethane resin, silicone resin, phenol resin, melamine resin, xylene resin, alkyd resin, heat Thermosetting resin such as cured acrylic resin; photocurable resin; photoconductive resin 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 resistance of 1 × 10 12 Ω · cm or more when measured alone.

As the charge generating material, bisazo pigments,
Triarylmethane dye, thiazine dye, oxazine dye, xanthene dye, cyanine dye, styryl dye, pyrylium dye, azo pigment, quinacridone pigment, indigo pigment, perylene pigment, polycyclic quinone Organic substances such as pigments, bisbenzimidazole pigments, indathrone pigments, squarium salt pigments, azulene pigments, phthalocyanine pigments, selenium, selenium,
Inorganic substances such as tellurium, selenium alloys such as selenium and arsenic, cadmium sulfide, cadmium selenide, zinc oxide, amorphous silicon, and the like. In addition, any material that absorbs light and generates charge carriers at an extremely high probability can be used.

As the conductive support used in the photoreceptor of the present invention, a sheet or drum made of foil or plate of a metal or alloy such as copper, aluminum, silver, iron, zinc, nickel or the like is used. Alternatively, these metals are vacuum-deposited or electroless-plated on a plastic film or the like, 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.

FIGS. 1 to 5 schematically show examples of the constitution of a photoreceptor using the triphenylamine compound of the present invention. FIG.
Is a photoconductor in which a photosensitive layer (4) in which a temporary conductive material (3) and a charge transport material (2) are mixed with a binder is formed on a substrate (1). Triphenylamine compounds have been used. In addition, FIG.
Have the same meaning as described above. FIG.
Is a function-separated type photoconductor having a charge generation layer (6) as a photosensitive layer and a charge transport layer (5). The charge transport layer (5) is formed on the surface of the charge generation layer (6). The charge transport layer (5) contains the triphanylamine compound of the present invention. FIG. 3 shows a function-separated type photoreceptor having a charge generation layer (6) and a charge transport layer (5) as in FIG. 2, but the charge transfer layer (5) has a surface opposite to FIG. A generating layer (6) is formed.

FIG. 4 shows that the surface of the photoreceptor shown in FIG. 1 is further provided with a surface protective layer (7). The photosensitive layer (4) has a charge generation layer (6) and a charge transport layer (5). A function-separated type photoconductor may be used. As the material used for the surface protective layer, acrylic resin, polyaryl resin, polycarbonate resin, polymers such as urethane resin as it is,
Alternatively, a material in which a low-resistance compound such as tin oxide or indium oxide is dispersed is suitable. FIG. 5 shows the base (1).
An intermediate layer (8) is provided between the photosensitive layer (4) and the photosensitive layer (4). The intermediate layer (8) improves adhesion, improves coating properties, protects the substrate, and charges the photosensitive layer from the substrate. It can be provided to improve the injection property.

As the material used for the intermediate layer, a polymer such as polyimide, polyamide, nitrocellulose, polyvinyl butyral, or polyvinyl alcohol as it is, or a dispersion of a low-resistance compound such as tin oxide or indium oxide, aluminum oxide, A vapor-deposited film of zinc oxide, silicon oxide, or the like is suitable. The thickness of the intermediate layer is desirably 1 μm or less.

[0031]

EXAMPLES (Synthesis example) The following formula [IV] (Chemical formula 9)

Embedded image 10 parts by weight of 7-aminocoumarin, 30.2 parts by weight of iodobenzene, 20.6 parts by weight of potassium carbonate, and 18.9 parts by weight of copper in 180 parts by weight of 70 parts by weight of nitrobenzene
The mixture was heated and reacted at 190 ° C. After the reaction, methanol was added to precipitate crystals. The precipitate was filtered, washed with methanol, and purified by column chromatography on silica gel to obtain 15.5 parts by weight of a crystal represented by the following formula (1). Elemental analysis was as follows.

[0032]

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In the following examples, unless otherwise specified.
“Parts” is “parts by weight”. (Example 1) The following general formula [A]

Embedded image Was dispersed with a sand grinder together with 50 parts of cyclohexanone together with 0.45 part of a bisazo compound represented by the following formula and 0.45 part of a polyester resin (Vylon 200; manufactured by Toyobo Co., Ltd.). The resulting dispersion of the bisazo compound was applied on a 100-μm-thick aluminized mylar using a film applicator so that the dry film thickness was 0.3 g / m ^2, and then dried. On the charge generation layer thus obtained, 70 parts of a triphenylamine compound (1) {exemplified compound (1)} and a polycarbonate resin (K-13)
00; Teijin Chemicals Ltd.) 70 parts with 1,4-dioxane 400
The solution dissolved in the portion was applied so that the dry film thickness became 16 μm to form a charge transport layer. In this way, an electrophotographic photoreceptor having two photosensitive layers was obtained. The photoreceptor thus obtained was converted to a commercially available electrophotographic copying machine (EP-470Z;
(Minolta Camera Co., Ltd.), and the exposure amount E1 / 2 (lux) required for corona charging at -6 KV to reduce the initial surface potential Vo (V) and the initial potential to 1/2 at the first and 1000th times.
Sec), and the decay rate DDR ₁ (%) of the initial potential when left in the dark for 1 second.

Example 2 The following general formula [B]

Embedded image Was dispersed with a sand grinder together with 50 parts of cyclohexanone together with 0.45 parts of a bisazo compound represented by the following formula (1) and 0.45 parts of a polystyrene resin (molecular weight: 40000).
Using a film applicator, apply the obtained bisazo compound dispersion on an aluminized mylar having a thickness of 100 μm.
The coating was applied so that the dry film thickness became 0.3 g / m ² and then dried. On the charge generation layer thus obtained, 70 parts of a triphenylamine compound {Exemplified Compound (5)} and 70 parts of a polyarylate resin (U-100; manufactured by Unitika)
A solution in which 400 parts of 1,4 dioxane was dissolved was applied so as to have a dry film thickness of 16 μm to form a charge generation layer. Thus, an electrophotographic photoreceptor having a two-layer photosensitive layer was produced.

(Examples 3 and 4) In the same manner as in Example 2 and having the same constitution, except that the triphenylamine compound {exemplified compound (5)} used in Example 2 was replaced with a triphenylamine compound Photoreceptors using the exemplified compounds (6) and (7) were prepared.
The photosensitive member thus obtained was subjected to Vo, E1 / 2 and DDR ₁ at the first and 1000th times in the same manner as in Example _1.
Was measured.

Example 5 50 parts of copper phthalocyanine and 0.2 parts of tetranitro copper phthalocyanine were dissolved in 500 parts of 98% concentrated sulfuric acid with sufficient stirring, and the mixture was poured into 5000 parts of water, and copper phthalocyanine and tetranitro copper phthalocyanine were dissolved. After precipitating the photoconductive material composition, it was filtered, washed with water, and dried at 120 ° C. under reduced pressure. 10 parts of the photoconductive composition thus obtained are 22.5 parts of a thermosetting acrylic resin (Acrytic A405; manufactured by Dainippon Ink) and 7.5 parts of a melamine resin (Super Beckamine J820; manufactured by Dainippon Ink). 48 parts of the above-mentioned triphenylamine compound {exemplified compound (8)} together with 100 parts of a mixed solvent obtained by mixing methyl ethyl ketone and xylene in the same amount are placed in a ball mill pot.
This was dispersed for a time to prepare a photosensitive coating solution, and the coating solution was applied on an aluminum substrate and dried to form a photosensitive layer having a thickness of about 15 μm, thereby producing a photoreceptor. The photosensitive member thus obtained was subjected to the same method as in Example 1, except that the corona charge was + 6K.
The first and the 1000 round of Vo, E1 / 2 carried out in V, and to measure the DDR _1.

(Example 6) A compound having the same constitution as in Example 5, except that the triphenylamine compound {Exemplified Compound (8)} used in Example 5 is replaced by an exemplary compound as a triphenylamine compound A photoreceptor using (9) was produced. The thus obtained photosensitive member, Example 5 the first and in the same way as 1000 th Vo, E1 / 2, and to measure the DDR _1.

(Comparative Examples 1 to 4) Compounds of the same construction and in the same manner as in Example 5, except that the triphenylamine compound {exemplified compound (8)} used in Example 5 was replaced by the following compound [C ], [D],
Example 5 except that each of [E] and [F] (Formula 13) was used.
A photoreceptor was produced in exactly the same manner as described above.

[0039]

Embedded image The photosensitive member thus obtained was subjected to Vo, E1 / 2, and DD at the first and 1000th times in the same manner as in Example 5.
It was measured R _1.

(Comparative Examples 5 to 8) The same configuration as in Example 5, except that the triphenylamine compound {Exemplified Compound (8)} used in Example 5 was replaced with the following aminobiphenyl compound [ G],
A photoconductor was prepared in the same manner as in Example 5 except that [H], [I], and [J] (Formula 14) were used.

[0041]

Embedded image

The photosensitive member thus obtained was subjected to the first and 1000th Vo, E1 / 2 tests in the same manner as in Example 5.
, And DDR ₁ were measured. Examples 1 to 6, Comparative Example 1
The first and 1000th Vos of the photoreceptor obtained in
E1 / 2, and are summarized in Table 1 The measurement results of the DDR _1.

[0043]

[Table 1]

As can be seen from Table 1, the photoreceptor of the present invention has a sufficient charge retention ability and a small dark decay rate as a photoreceptor so that it can be used as a photoreceptor.
The sensitivity is also excellent, and the sensitivity does not decrease due to repetition.

[0045]

The present invention has provided a photoconductive compound useful for a photoreceptor. The photoconductive compound of the present invention is particularly useful as a charge transport material. The photoreceptor of the present invention having a triphenylamine compound having a coumarin ring in a molecule is excellent in photoreceptor characteristics such as sensitivity, charge transport property, initial surface potential, and dark decay rate, and has less light fatigue upon repeated use.

[Brief description of the drawings]

FIG. 1 is a schematic view of the structure of a dispersion type photoconductor in which a photoconductive layer is laminated on a conductive support according to the present invention.

FIG. 2 is a schematic view of a structure of a function-separated type photoconductor in which a charge generation layer and a charge transport layer are laminated on a conductive support according to the present invention.

FIG. 3 is a schematic diagram of another embodiment.

FIG. 4 is a schematic view of the structure of another embodiment of a dispersion type photoreceptor obtained by laminating a photosensitive layer on a conductive support according to the present invention.

FIG. 5 is a schematic view of another embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive support 2 charge transport material 3 photoconductive material 4 photosensitive layer 5 charge transport layer 6 charge generation layer 7 surface protection layer 8 intermediate layer

Claims (1)

(57) [Claims] 1. A conductive support having the following general formula [I]
A photosensitive member having a photosensitive layer containing a triphenylamine compound represented by the following formula (1). Embedded image [In the formula, R ¹ represents a hydrogen atom, an optionally substituted alkyl group or a benzothiazole group, and R ² represents a hydrogen atom, an optionally substituted alkyl group or a cyano group. R ³ , R ⁴ and R ⁵ each independently represent a hydrogen atom, an alkyl group which may have a substituent, an alkoxy group, a thioalkoxy group, an aryloxy group or a halogen atom.