JPH08272115A - Electrophotography photoreceptor - Google Patents

Abstract

PURPOSE: To provide an electrophotography photoreceptor satisfying various kinds of electrophotography characteristics. CONSTITUTION: On a conductive support body, a photosensitive layer containing at least one kind of stilboene compound represented by the formula as an effective constituent is provided. In the formula, Ar<1> , Ar<2> represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, while Ar<3> represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group, and they may be the same or different. R<1> , R<2> represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted acyl group, and they may be the same or different. However, R<1> and R<2> cannot be alkyl groups at the same time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing a specific compound.

[0002]

2. Description of the Related Art Conventionally, inorganic materials such as selenium, cadmium sulfide and zinc oxide have been used as photoconductive materials for photoconductors used in electrophotography.
The term "electrophotographic method" as used herein generally means that a photoconductive photoconductor is first charged in a dark place by, for example, corona discharge, and then imagewise exposed to static electricity by selectively dissipating charges only in the exposed portion. An electrostatic latent image is obtained, and the latent image portion is developed with electroscopic fine particles (toner) composed of a coloring material such as a dye or a pigment and a binder such as a polymer substance and visualized to form an image. This is one of the image forming methods. The basic characteristics required for the photoconductor in such an electrophotographic method are as follows.
(1) Charging to an appropriate potential in a dark place, (2) Little dissipation of charges in a dark place, and (3) Capability of promptly dissipating charges by light irradiation.

By the way, the above-mentioned inorganic substances have many advantages, and at the same time, have various drawbacks. For example, selenium, which is widely used at present, satisfies the above conditions (1) to (3) sufficiently, but the manufacturing conditions are difficult, the manufacturing cost is high, and the selenium is not flexible and must be processed into a belt shape. However, it is difficult to handle, and it is sensitive to heat and mechanical shock, so it requires careful handling. Cadmium sulfide and zinc oxide are used as photoreceptors by dispersing them in a resin as a binder, but because of mechanical defects such as smoothness, hardness, tensile strength, and abrasion resistance, they can be repeated as they are. And cannot be used. In recent years, electrophotographic photoreceptors using various organic substances have been proposed to eliminate the drawbacks of these inorganic substances, and some of them have been put to practical use. For example,
A photoreceptor comprising poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (described in U.S. Pat. No. 3,484,237), poly-N-vinylcarbazole added with a pyrylium salt dye. A photosensitive material (described in JP-B-48-25658), a photosensitive material containing an organic pigment as a main component (described in JP-A-47-37543), and a eutectic complex composed of a dye and a resin. A photoreceptor containing a main component (described in JP-A-47-10735), a photoreceptor obtained by dye-sensitizing a triphenylamine compound (US Pat. No. 3,180,730), and a triarylamine derivative having a charge Photoreceptor used as transportation material
65440), a photoreceptor using an amine derivative as a charge transport material (JP-A-57-195254), poly-
A photoconductor using N-vinylcarbazole and an amine derivative as a charge transport material (JP-A-58-1155),
A photoconductor using a benzidine compound as a photoconductive material among polyfunctional tertiary amine compounds (US Pat.
5,496, Japanese Examined Patent Publication No. 39-11546, Japanese Patent Laid-Open No. 53-27033). These photoconductors have excellent properties and are considered to be of high value practically.However, in consideration of various demands on the photoconductor in the electrophotographic method, these demands are still insufficient. It is the actual situation that nothing satisfying the above is obtained.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the various drawbacks of the conventional photoconductors described above and to provide a photoconductor that can sufficiently satisfy the conditions required in the electrophotographic method. It is in. Another object of the present invention is to provide an electrophotographic photoreceptor which is easy to manufacture, can be produced at a relatively low cost, and has excellent durability.

[0005]

As a result of intensive studies, the present inventors have found that the above problems can be solved by a stilbene compound having a specific structure, and have completed the present invention. That is, the present invention is the following (1) to (5). (1) An electrophotographic photoreceptor, which has a photosensitive layer containing at least one stilbene compound represented by the following general formula I as an active ingredient on a conductive support.

[0006]

Embedded image

(In the formula, Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group. Represent
They may be the same or different. R ¹ and R ² represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted acyl group, and may be the same or different. However, the case where R ¹ and R ² are simultaneously an alkyl group is excluded. (2) The electrophotographic photoreceptor according to (1), wherein the stilbene compound is represented by the following general formula II.

[0008]

[Chemical 6]

(Wherein Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group. Represent
They may be the same or different. R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted acyl group. (3) The electrophotographic photoreceptor according to (1), wherein the stilbene compound is represented by the following general formula III.

[0010]

[Chemical 7]

(In the formula, Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group. Represent
They may be the same or different. (4) The electrophotographic photoreceptor according to (1), wherein the stilbene compound is represented by the following general formula IV.

[0012]

Embedded image

(Wherein Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group. Represent
They may be the same or different. (5) The electrophotographic photoconductor of (1), wherein the photosensitive layer is a laminated type of a charge generation layer and a charge transport layer. In the present invention, the stilbene compound represented by the general formula I contained in the photosensitive layer can be produced, for example, by the following method.

[0014]

[Chemical 9]

(In the formula, Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group, and R ¹ and R ² are hydrogen atoms, substituted or unsubstituted alkyl groups, substituted or unsubstituted And an amino compound represented by an acyl group, which may be the same or different) and the following general formula V Ar ¹ X (V) (wherein Ar ¹ is a substituted or unsubstituted carbocyclic aromatic group). Represents a valent group, X represents a halogen atom) and the following general formula VI Ar ² X (VI) (wherein Ar ² represents a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and X Represents a halogen atom.
² , X may be the same as Ar ¹ , X. In the presence of a solvent or without a solvent, a halogen compound represented by the formula (1) is added to copper powder, copper oxide, copper halide, etc., and an alkaline substance in an amount sufficient to neutralize the hydrogen halide generated during the condensation reaction. It is manufactured by reacting under a nitrogen atmosphere at a temperature of about 150 to 250 ° C. In this case, the alkaline substance is sodium hydroxide,
Examples thereof include potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydride and the like. Further, as the reaction solvent, nitrobenzene, dichlorobenzene, quinoline, N, N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-dimethyl-2-
Examples thereof include imidazolidinone, tetrahydrofuran, carbon disulfide and the like. Further, as another method for synthesizing the stilbene compound represented by the general formula I, the following general formula VI
I

[0016]

[Chemical 10]

(In the formula, Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group. Represent
They may be the same or different. ) And an aldehyde compound represented by the following general formula VIII

[0018]

[Chemical 11]

[In the formula, R ¹ and R ² represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted acyl group, and may be the same or different. Y is -P ⁺
(R ³ ) ₃ X ⁻ (wherein R ³ represents a phenyl group or a lower alkyl group, X represents a halogen atom) or —PO (OR ⁴ ) ₂ (wherein R ⁴ represents a lower alkyl group) Represents a dialkyl phosphite group. ] It is also produced by reacting a phosphorus compound represented by the following in the presence of a basic catalyst at a temperature from room temperature to about 100 ° C. In this case, examples of the basic catalyst include phenyllithium, sodium hydroxide, potassium hydroxide, sodium amide, sodium hydride and sodium methylate, and alcoholates such as potassium-t-butoxide. Further, as a reaction solvent, methanol, ethanol, isopropanol, butanol, 2-methoxyethanol, 1,2-dimethoxyethane, bis (2-methoxyethyl) ether, dioxane, tetrahydrofuran, benzene, toluene, xylene, dimethylsulfoxide, N, N -Dimethylformamide, N-methylpyrrolidone, 1,3-dimethyl-2
-Imidazolidinone and the like can be mentioned. Among them, polar solvents such as N, N-dimethylformamide and methyl sulfoxide are preferable.

The reaction temperature is 1) the stability of the solvent used with respect to the basic catalyst, and 2) the condensation component (the above general formulas III and I).
A wide range of compounds can be selected depending on the reactivity of the compound (V)) and the reactivity of the basic catalyst as a condensing agent in a solvent. For example, when a polar solvent is used, it is actually room temperature to 100 ° C, preferably room temperature to 80 ° C. However, higher temperatures may be used when shortening the reaction time or using a less active condensing agent. In addition, the general formula
The stilbene compounds represented by II and III are represented by the following general formula IX

[0021]

[Chemical 12]

(In the formula, Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group. Represent
They may be the same or different. R ⁵ and R ⁶ represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted acyl group, and may be the same or different. However, the case where R ⁵ and R ⁶ are both hydrogen atoms is excluded. )
It can also be obtained by dealkylation or deacylation of the stilbene compound represented by. Specifically, in the case of dealkylation, cleavage reaction with an acidic reagent and cleavage reaction with a basic reagent can be mentioned. Examples of acidic reagents include hydrogen bromide, hydrogen iodide, trifluoroacetic acid, pyridine hydrochloride, concentrated hydrochloric acid, and iodide. Magnesium etherate, aluminum chloride, aluminum bromide, boron tribromide, boron trichloride,
Examples of basic reagents such as boron triiodide include potassium hydroxide, lithium diphenylphosphide, sodium thiolate, and the like. Examples of the solvent include dichloromethane, THF, DMF, pyridine, butanol, etc. The reaction temperature is generally room temperature to 200 ° C., although it depends on the reactivity of the reagent used.

In the case of deacylation, it is produced by deacylation under acidic or alkaline conditions. Examples of the acidic and basic reagents at this time include hydrochloric acid, sulfuric acid, sodium hydroxide, potassium hydroxide and the like,
As the reaction solvent, methanol, ethanol, isopropanol, butanol, 2-methoxyethanol, 1,2
-Dimethoxyethane, bis (2-methoxyethyl) ether, dioxane, tetrahydrofuran, benzene, toluene, xylene, dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone, 1,3-
Examples thereof include dimethyl-2-imidazolidinone. The stilbene compound represented by the general formula I obtained by the above production method will be described in more detail. Specific examples of Ar ¹ , Ar ² , Ar ³ , R ¹ , R ² in the general formula I and X in the general formulas V and VI, or substituents thereof, include the following.

(1) Halogen atom: Fluorine, chlorine, bromine, iodine and the like can be mentioned. (2) alkyl radical; preferably C ₁ -C ₁₂ especially C ₁ ~
C ₉ and more preferably C _{1 to} C ₄ straight chain or branched chain alkyl groups, and these alkyl groups further include C ₁
An alkyl group -C ₄ may contain substituted or unsubstituted phenyl group. Specifically, methyl group, ethyl group, n
-Propyl group, i-propyl group, t-butyl group, s-butyl group, n-butyl group, i-butyl group, benzyl group, 4
-Methylbenzyl group, 4-phenylbenzyl group and the like can be mentioned.

(3) Phenyl group;

[0026]

[Chemical 13]

R ⁷ represents a hydrogen atom or a substituent defined in (1) to (2). Specific examples thereof include a phenyl group, a tolyl group and a chlorophenyl group. (4) acyl group;

[0028]

Embedded image

R ⁸ represents an alkyl group or a phenyl group defined in (2) to (3). Specific examples include an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a valeryl group, an isovaleryl group and a pivaloyl group.

(5) Carbocyclic aromatic group Examples of the non-condensed carbocyclic aromatic group include phenyl group, biphenyl group and terphenyl group. Examples of the condensed polycyclic hydrocarbon group include pentalenyl group and indenyl group. Base,
Naphthyl group, azulenyl group, heptanenyl group, biphenylenyl group, as-indacenyl group, fluorenyl group, s
-Indacenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrylenyl group, aceanthrylenyl group, triphenylenyl group, pyrenyl group, chrysenyl group and naphthalcenyl group Groups and the like. In addition, these are (1) to (3)
It may have a substituent defined in. Specific examples of the stilbene compound represented by the following general formula I used in the present invention are shown in Table 1.
Shown in

[0031]

[Chemical 15]

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

[0035]

[Table 4]

[0036]

[Synthesis Example of Compound No. 1]

Production of 4′-bis (4-methylphenyl) amino-3,5-dihydroxystilbene 4′-bis (4-methylphenyl) amino-3,5-dimethoxystilbene 4.36 g (10.0 mmol) and 90% sodium Thioethylate 14.02 g (15
0.2 mmol) was added to 40 ml of N, N-dimethylformamide treated with Molecular Ships 4A, and the mixture was stirred at 145 to 155 ° C. for 12 hours under a nitrogen stream. After the reaction solution was cooled to room temperature, it was poured into 500 ml of ice water, acidified with concentrated hydrochloric acid, and extracted with ether. The solvent of this extract was distilled off, and the residue was subjected to silica gel column chromatography (eluent: toluene / ethyl acetate 5/1 vol.). As a result, 4'-bis (4-methylphenyl) amino-3,
1.65 g of 5-dihydroxystilbene (yield 40.5
%) Yellow needle crystals were obtained. The melting point is 161.3 ° C (TG-
DTA endothermic peak). Elemental analysis value is C ₂₈ H ₂₅ N
The O ₂ was as follows.

[0037] In addition, the following absorption was confirmed by the infrared absorption spectrum (KBr tablet method). ν _s OH = 3450 cm ⁻¹ δCH (trans olefin) = 965 cm ⁻¹ Example 1 76 parts of Diane Blue (CI Pigment Blue 25, CI No. 21180) as a charge generating substance, polyester resin [Vylon 200, (stock 1260 parts of a 2% tetrahydrofuran solution manufactured by Toyobo Co., Ltd.) and 3700 parts of tetrahydrofuran were pulverized and mixed in a ball mill, and the obtained dispersion was aluminum-deposited on a conductive base made of a polyester base, and a doctor blade was used on the aluminum surface. Was applied and naturally dried to form a charge generation layer having a thickness of about 1 μm. On the other hand, as a charge carrier substance, 2 parts of a stilbene compound of compound No. 1, 2 parts of a polycarbonate resin [Panlite K1300, manufactured by Teijin Ltd.] and 16 parts of tetrahydrofuran were mixed and dissolved to form a solution, which was charged with the above-mentioned charge. A photoconductor No. 1 was prepared by coating on the generating layer with a doctor blade and drying at 80 ° C. for 2 minutes and then at 120 ° C. for 5 minutes to form a charge carrying layer having a thickness of about 20 μm.

Examples 2 to 46 Photosensitive members Nos. 2 to 46 were prepared in exactly the same manner as in Example 1 except that the charge generating substance and the charge carrier substance (stilbene compound) were replaced with those shown in Table 2.

[0039]

[Table 5]

[0040]

[Table 6]

[0041]

[Table 7]

[0042]

[Table 8]

Example 47 Selenium was vacuum-deposited to a thickness of about 1 μm on an aluminum plate having a thickness of about 300 μm to form a charge generation layer. Next, No. 1 stilbene compound 2 parts, polyester resin (DuPont Polyester Adhesive 49000)
3 parts and 45 parts of tetrahydrofuran are mixed and dissolved to prepare a charge transport layer forming liquid, which is applied onto the above charge generation layer (selenium vapor deposition layer) using a doctor blade and naturally dried, and then under reduced pressure. After drying, a charge carrying layer having a thickness of about 10 μm was formed to obtain a photoconductor No. 47 of the present invention.

Example 48 Perylene pigment instead of selenium

[0045]

Embedded image

A charge generation layer (with a thickness of about 0.
6 μm) and a stilbene compound No. 1 was used as a charge carrier, and a photoconductor No. 48 was prepared in the same manner as in Example 47. Example 49 A mixture of 1 part of Diane Blue (the same as that used in Example 1) and 158 parts of tetrahydrofuran was ground and mixed in a ball mill, and then 12 parts of a stilbene compound No. 1 and a polyester resin ( Dupont Polyester Adhesive 49000) 18 parts was added, and the photosensitive layer forming liquid obtained by further mixing was applied onto an aluminum vapor-deposited polyester film using a doctor blade,
By drying at 100 ° C. for 30 minutes to form a photosensitive layer having a thickness of about 16 μm, a photosensitive member No. 49 of the present invention was prepared.

Example 50 On an aluminum-deposited polyester film substrate,
The charge transport layer coating liquid used in Example 1 was blade coated in the same manner as in Example 1, and then dried to form a charge transport layer having a thickness of about 20 μm. Bisazo pigment (P-2) 13.
5 parts, polyvinyl butyral (trade name: XYHL Union Carbide Plastic Co., Ltd.) 5.4 parts, THF68
After 0 parts and 1020 parts of ethyl cellosolve were crushed and mixed in a ball mill, 1700 parts of ethyl cellosolve were added and mixed by stirring to obtain a coating liquid for charge generation layer. This coating solution is spray-coated on the above charge transport layer, and the temperature is maintained at 100 ° C. for 10 minutes.
After drying for a minute, a charge generation layer having a thickness of about 0.2 μm was formed. Further, a methanol / n-butanol solution of a polyamide resin (trade name: CM-8000, manufactured by Toray) is spray-coated on the charge generation layer and dried at 120 ° C. for 30 minutes to form a protective layer having a thickness of about 0.5 μm. To form photoconductor No.
Created 50.

The photoreceptors No. 1 to 50 thus produced were charged by corona discharge of -6 KV or +6 KV for 20 seconds using a commercially available electrostatic copying paper tester (SP428 type manufactured by KK Kawaguchi Electric Co., Ltd.). After that, it is left in a dark place for 20 seconds, the surface potential V _po (volt) at that time is measured, and then the tungsten lamp light is irradiated so that the illuminance on the surface of the photoconductor becomes 4.5 ×, and the surface potential becomes V _po
The time (second) until it becomes 1/2 of the
_1/2 (lux seconds) was calculated. Table 3 shows the results. Also, after charging each of the above photoconductors using a commercially available electrophotographic copying machine, light irradiation was performed through the original drawing to form an electrostatic latent image, and the latent image was developed using a dry developer, and thus obtained. When the image (toner image) was electrostatically transferred and fixed on plain paper, a clear transferred image was obtained. Even when a wet type developer was used as the developer, a clear transfer image was similarly obtained.

[0049]

[Table 9]

[0050]

[Table 10]

[0051]

[Table 11]

Comparative Example A photoconductor No. 51 was prepared in the same manner as in Example 1 except that the charge generating substance and the charge carrier substance were changed to those shown in Table 4.

[0053]

[Table 12]

With respect to the photoconductor No. 51 thus obtained, the same measurement as that described above was carried out. The results are shown in Table 5.

[0055]

[Table 13]

[0056]

As described above, the photoconductor of the present invention is excellent not only in the photosensitivity but also in the strength against heat and mechanical shock, and can be manufactured at low cost.

Claims (5)

[Claims] 1. An electrophotographic photoreceptor comprising a conductive layer and a photosensitive layer containing at least one stilbene compound represented by the following general formula I as an active ingredient. Embedded image (In the formula, Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group, respectively. R ¹ and R ² represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted acyl group, and may be the same or different.
Except when R ¹ and R ² are simultaneously an alkyl group. ) 2. The electrophotographic photoconductor according to claim 1, wherein the stilbene compound is represented by the following general formula II. Embedded image (In the formula, Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group, respectively. They may be the same or different. R ¹ represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted acyl group.) 3. The electrophotographic photoreceptor according to claim 1, wherein the stilbene compound is represented by the following general formula III. Embedded image (In the formula, Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group, respectively. It may be the same or different.) 4. The electrophotographic photoreceptor according to claim 1, wherein the stilbene compound is represented by the following general formula IV. [Chemical 4] (In the formula, Ar ¹ and Ar ² represent a monovalent group of a substituted or unsubstituted carbocyclic aromatic group, and Ar ³ represents a divalent group of a substituted or unsubstituted carbocyclic aromatic group, respectively. It may be the same or different.) 5. The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer is a laminated type of a charge generation layer and a charge transport layer.