JP2979024B2 - Azo compounds and photoreceptors using them - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel compound which can be used for a photoreceptor and a photoreceptor using the compound as a charge generating agent.

[0002]

2. Description of the Related Art Conventionally, inorganic photosensitive materials such as selenium, cadmium sulfide, and zinc oxide have been widely used as photosensitive materials for electrophotographic photosensitive members. However, photoreceptors using these photosensitive materials have not sufficiently satisfied the required performance as an electrophotographic photoreceptor, such as sensitivity, light stability, moisture resistance, and durability. For example, a photoreceptor using a selenium-based material has excellent sensitivity, but is easily crystallized due to heat or adhesion of dirt, and the characteristics of the photoreceptor are easily deteriorated. In addition, it has many drawbacks, such as high cost because it is manufactured by vacuum evaporation, and difficulty in processing it into a belt shape due to lack of flexibility. A photoreceptor using a cadmium sulfide-based material has a problem in moisture resistance and durability, and a photoreceptor using zinc sulfide has a problem in durability.

In order to overcome the drawbacks of the photoreceptor using an inorganic photosensitive material, various photoreceptors using an organic photosensitive material have been studied. For example, as organic light-sensitive materials that have been partially put into practical use, those using a combination of 2,4,7-trinitro-9-fluorenone and poly N-vinylcarbazole are known. However, the photoreceptor using this had low sensitivity and was not satisfactory in durability.

[0004] In recent years, among photoconductors developed to improve the above-mentioned drawbacks, a function-separated type photoconductor in which a charge generation function and a charge transport function are shared by individual substances has attracted attention. In this function-separated type photoreceptor, substances having respective functions can be selected from a wide range and combined, so that a photoreceptor having high sensitivity and high durability can be manufactured. Many substances have been proposed as charge generating substances for use in such a function-separated type photoreceptor. Among them, a photoreceptor using an organic dye or an organic pigment as a charge generating substance has been receiving particular attention in recent years. For example, a photoconductor using a disazo pigment having a styrylstilbene skeleton (JP-A-53-133445), a photoconductor using a disazo pigment having a carbazole skeleton (JP-A-53-95033), triphenylamine Photoreceptor using trisazo pigment having skeleton
-132347), a photoreceptor using a disazo pigment having a distyrylcarbazole skeleton (JP-A-54-1)
No. 4967), and a photoreceptor using a disazo pigment having a bisstilbene skeleton (Japanese Patent Application Laid-Open No. 54-17733). However, these electrophotographic photoreceptors do not always sufficiently satisfy the required performance, and in particular, the light source is a semiconductor laser (650 to 850).
nm) or an LED (600-700 nm) has the disadvantage that the sensitivity is extremely poor.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor laser or LED having sufficient sensitivity when used as a light source,
Another object of the present invention is to provide a charge generating agent having excellent durability and a photoreceptor using the same.

[0006]

Means for Solving the Problems The present inventors diligently studied to solve the above-mentioned problems, and as a result, the azo compound represented by the above general formula (I) (formula 1) has high sensitivity and high sensitivity. The present inventors have found that an electrophotographic photoreceptor having excellent properties such as durability is provided, and have accomplished the present invention.

In the general formula (I), 2 represented by Ar ¹
Examples of the tetravalent linking group include benzene, naphthalene, anthracene, pyrene, phenanthrene, fluorene, biphenyl, anthraquinone, fluorenone, benzuanthrone, thiophene, dibenzothiophene, pyridine, carbazole, benzoxazole, and benzothiazole.

Embedded image And the like. When the compound has a substituent, examples of the substituent include an alkyl group such as a methyl group, an ethyl group, a propyl group and a butyl group, an alkoxy group such as a methoxy group, an aryl group such as a phenyl group and a naphthyl group, a diethylamino group, and a diphenyl group. Examples include a substituted amino group such as an amino group, a halogen atom such as a fluorine atom, a chlorine atom, and a bromine atom, a hydroxyl group, a nitro group, and a cyano group.

Ar ^{1 which} can be preferably used in the present invention
Are specifically exemplified below. When n = 2

Embedded image

Embedded image When n = 3

Embedded image When n = 4

Embedded image Particularly preferred linking groups used for semiconductor laser light sources and LED light sources are (A-3), (A-6), and (A-
7), (A-10), (A-11), (A-12),
It is represented by (A-13), (A-14), (A-15) and the following formula (A-16).

Embedded image [Groups represented by Z ¹ and Z ² in Formula (A-16) represent cyano, alkoxycarbonyl, and trifluoromethyl]

In Ar ² , examples of the aromatic hydrocarbon ring include benzene, naphthalene, anthracene, anthraquinone, pyrene, phenanthrene, fluorene, and fluorenone.
Examples include furan, pyridine, carbazole, indole, quinoline, benzofuran, dibenzofuran, coumarin and the like. When it has a substituent, as a substituent, an alkyl group such as a methyl group, an ethyl group, a propyl group, or a butyl group, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, or a butoxy group, a chlorine atom, a fluorine atom, or a bromine atom And the like, a halomethyl group such as a trifluoromethyl group, a dialkylamino group such as a dimethylamino group and a diethylamino group, a nitro group, a cyano group, a carboxyl group or an ester thereof. Also, X
Specific examples include a hydrocarbon ring such as a naphthalene ring and an anthracene ring formed by condensing with a benzene ring to which an azo group is bonded, and a heterocyclic ring such as an indole ring, a carbazole ring, a benzocarbazole ring, and a dibenzofuran ring. ,
Naphthalene rings are particularly preferred. X may have a substituent, and examples of the substituent include a halogen atom such as a chlorine atom and a bromine atom, and a hydroxyl group.

Specific examples of the azo compounds which can be preferably used in the present invention are shown in Tables 1 to 6 below. In the table, (A-1) to (A-16) in Ar ¹ represent the structural formulas exemplified above. The general formulas of the compounds shown in Tables 1 to 3 are shown below.

Embedded image

[Table 1]

[Table 2]

[Table 3]

Tables 4 to 6 show compounds of the following general formulas.

Embedded image

[Table 4]

[Table 5]

[Table 6]

The compound of the present invention can be synthesized using the following method. Organic Synthesis Collective Vol. III, p.78-
Synthesized according to p.82. The following formula (II)

Embedded image (III) wherein the compound of formula (III) is acylated in a broad sense with an acid halide or the like.

Embedded image [Formula (III) medium R, Y ^1, Y ³ represents R of the general formula (I) (Formula 1), the same meaning as Y ^1, Y ^3. Is acid chlorided with thionyl chloride, PCl ₃ , POCl _{3 and the} like, and then Ar ² Y ² —H [Ar ² , Y ² has the same meaning as in the general formula (I). With the formula (IV)

Embedded image [In the formula (IV), R, Y ¹ , Y ² , Y ³ , Ar ² and X have the same meaning as in the general formula (I). ] Was obtained.

Formula (V) (Formula 13)

Embedded image (Wherein n is the same as in general formula (I)), and then diazotize the amine compound represented by the formula (I), and then isolate the diazotized compound as it is or as a borofluoride salt,
The compound of the present invention can be easily produced by coupling with the coupler compound represented by the general formula (IV).

The electrophotographic photoreceptor of the present invention has the general formula (I)
At least one of the azo compounds represented by the formula (I) is contained in the photosensitive layer on the conductive support as a charge generating substance. A typical configuration of such a photoreceptor is shown in FIGS. FIG. 1 shows a photoconductor in which a dispersion type photosensitive layer 4 in which a charge generation material 2 and a charge transport material 3 are dispersed in a binder is provided on a conductive support 1. Provided a laminated photosensitive layer 4 'comprising a charge generating layer 6 in which a charge generating substance 2 is dispersed in a binder and a charge transporting layer 5 in which a charge transporting substance 3 is dispersed in a binder. It is a photoconductor. Other examples include those in which the charge generation layer and the charge transport layer are reversed, and those in which an intermediate layer is provided between the photosensitive layer and the conductive support.

In the photoreceptor shown in FIG. 2, the image-exposed light passes through the charge transport layer, and the charge generating substance generates charges in the charge generating layer. The generated charges are injected into the charge transport layer, and the charge transport material transports the charge.

The electrophotographic photoreceptor of the present invention comprises, in addition to the azo compound of the general formula (I), a conductive support, a binder,
The other components of the photoconductor are not particularly limited as long as the components include a charge transport material and the like and function as components of the photoconductor. That is, as the conductive support used in the photoreceptor of the present invention, aluminum, copper, a metal plate of zinc or the like, a plastic sheet or a plastic film of polyester or the like,
A material obtained by vapor deposition of a conductive material such as SnO ₂ , or a paper, resin, or the like subjected to conductive treatment is used.

Examples of the binder include vinyl polymers such as polystyrene, polyacrylamide, and poly-N-vinylcarbazole, polyamide resins, polyester resins, and the like.
Although a condensed resin such as an epoxy resin, a phenoxy resin, and a polycarbonate resin is used, any resin having an insulating property and having an adhesive property to a support can be used.

The charge transporting materials are generally classified into two types, a hole transporting material and an electron transporting material, and both can be used in the photoreceptor of the present invention. Examples of the hole transport material include an electron-accepting material such as trinitrofluorenone or tetranitrofluorenone, which easily transports electrons, a polymer containing a heterocyclic compound represented by poly-N-vinylcarbazole, and triazole. Derivatives,
Electron-donating substances that easily transport holes such as oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, hydrazone derivatives, amino-substituted chalcone derivatives, triarylamine derivatives, carbazole derivatives, stilbene derivatives, etc. Substances.

For example, 9-ethylcarbazole-3-
Aldehyde-1-methyl-1-phenylhydrazone, 9
-Ethylcarbazole-3-aldehyde-1-benzyl-1-phenylhydrazone, 9-ethylcarbazole-
3-aldehyde-1,1-diphenylhydrazone, 4-
Diethylaminostyrene-β-aldehyde-1-methyl-1-phenylhydrazone, 4-methoxynaphthalene-
1-aldehyde-1-benzyl-1-phenylhydrazone, 4-methoxybenzaldehyde-1-methyl-1-
Phenylhydrazone, 2,4-dimethoxybenzaldehyde-1-benzyl-1-phenylhydrazone, 4-diethylaminobenzaldehyde-1,1-diphenylhydrazone, 4-methoxybenzaldehyde-1-benzyl-1- (4-methoxy) phenylhydrazone, 4-diphenylaminobenzaldehyde-1-benzyl-1-
Phenylhydrazone, 4-dibenzylaminobenzaldehyde-1,1-diphenylhydrazone, 1,1-bis (4-dibenzylaminophenyl) propane, tris (4-diethylaminophenyl) methane, 1,1-bis (4-diphenyl Benzylaminophenyl) propane, 2,2 '
-Dimethyl-4,4'-bis (diethylamino) -triphenylmethane, 9- (4-diethylaminostyryl)
Anthracene, 9-bromo-10- (4-diethylaminostyryl) anthracene, 9- (4-dimethylaminobenzylidene) fluorene, 3- (9-fluorenylidene) -9-ethylcarbazole, 1,2-bis (4-diethylaminostyryl) ) Benzene, 1,2-bis (2,
4-dimethoxystyryl) benzene, 3-styryl-9
-Ethylcarbazole, 3- (4-methoxystyryl)
-9-ethylcarbazole, 4-diphenylaminostyrylben, 4-dibenzylaminostyrylben, 4-ditolylaminostyrylben, 1- (4-diphenylaminostyryl) naphthalene, 1- (4-diethylaminostyryl) naphthalene, 4'-diphenylamino-α-phenylstilbene, 4'-methylphenylamino-α-
Phenylstilbene, 1-phenyl-3- (4-diethylaminostyryl) -5- (4-diethylaminophenyl) pyrazolin, 1-phenyl-3- (4-dimethylaminostyryl) -5- (4-dimethylaminophenyl)
And pyrazoline.

Other hole transporting substances include, for example, 2,5-bis (4-diethylaminophenyl)-
1,3,4-oxadiazole, 2,5-bis [4-
(4-Diethylaminostyryl) phenyl] -1,3
4-oxadiazole, 2- (9-ethylcarbazol-3-yl) -5- (4-diethylaminophenyl)-
1,3,4-oxadiazole, 2-vinyl-4- (2
-Chlorophenyl) -5- (4-diethylaminophenyl) oxazole, 2- (4-diethylaminophenyl) -4-phenyloxazole, 9- [3- (4-diethylaminophenyl) -2-propenylidene] -9H
-Xanthene, poly-N-vinylcarbazole, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, pyreneformaldehyde resin, ethylcarbazoleformaldehyde resin and the like.

Examples of the charge transporting substance include chloranil, bromanil, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, and 2,4,5,7-tetranitro-9-fluorene. , 2,4,5,7-tetranitroxanthone,
2,4,8-trinitrothioxanthone, 2,6,8-
Trinitro-4H-indeno [1,2-b] thiophen-4-one; 1,3,7-trinitrodibenzothiophene-5,5-dioxide; These charge transport materials are used alone or in combination of two or more.

If necessary, an intermediate layer can be provided between the photosensitive layer and the conductive support. As the material, polyamide, nitrocellulose, casein, polyvinyl alcohol and the like are suitable, and the film thickness is 1 μm or less. Is preferred.

For the preparation of the photoreceptor, a conventionally known method can be used. For example, in the case of a laminated photoreceptor, fine particles of an azo compound are dispersed in a solution in which a binder is dissolved, coated on a conductive support, and dried to obtain a charge generation layer. Then, a solution in which a binder is dissolved as a charge transport material is obtained. Is applied and dried to form a charge transport layer.
Other methods can be used to form the charge generation layer. For example, there is a method of vacuum-depositing an azo compound, or a method of applying and drying a solution of an azo compound. The former uses a high cost, and the latter uses an organic amine which is generally inconvenient to handle, for example, ethylenediamine, n-butylamine and the like. For example, a coating method of a fine particle dispersion of an azo compound is preferable because of the drawbacks in production. The coating method is performed by usual means, for example, doctor blade, dipping, wire bar and the like. The optimum range of the thickness of the photosensitive layer differs depending on the type of the photoconductor. For example, in the case of the photoconductor shown in FIG. 1, the thickness is preferably 3 to 50 μm, and more preferably 5 to 30 μm.

In the photoreceptor as shown in FIG. 2, the thickness of the charge generation layer 6 is preferably 0.01 to 5 μm, more preferably 0.05 to 2 μm. This thickness is 0.0
If it is less than 1 μm, the generation of electric charge is not sufficient, and if it exceeds 5 μm, the residual potential is high and is not practically preferable. Also,
The thickness of the charge transport layer 5 is preferably 3 to 50 μm, and more preferably 5 to 30 μm. If the thickness is less than 3 μm, the charge amount is insufficient. .

Although the content of the azo compound represented by the general formula (I) in the photosensitive layer varies depending on the type of the photosensitive member, in the photosensitive member as shown in FIG. %, More preferably 20% by weight or less. Further, this layer contains a charge transporting substance at a ratio of preferably 10 to 95% by weight, more preferably 30 to 90% by weight. In the case of a photoreceptor as shown in FIG.
The proportion of the azo compound therein is preferably at least 30% by weight, more preferably at least 50% by weight. The charge transport layer 5 contains a charge transport material in an amount of 10 to 95% by weight, preferably 30 to 90% by weight. If the amount of the charge transporting substance in this layer is less than 10% by weight, the charge is hardly transported. If the amount exceeds 95% by weight, the photoreceptor has poor mechanical strength and is not practically preferable.

[0026]

The electrophotographic photoreceptor of the present invention is easy to manufacture by using the azo compound represented by the general formula (I) as a charge generating material, and has excellent sensitivity and high performance without deterioration in repeated use. Has performance.

[0027]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but it should not be construed that the present invention is limited thereto. Production Example 1 2-acetylaminonaphthalene-3-carboxylic acid 25
g, 2-chloroaniline (15.7 g) in toluene (200 ml)
The mixture was added with 0.1 ml of N, N-dimethylformamide and 13.4 g of phosphorus trichloride, and heated under reflux for 8 hours. The residue obtained by distilling off toluene was recrystallized from a benzene-methanol-hexane solvent to obtain 23 g of a coupler compound represented by the following structural formula.

Embedded image 4.0 g of this coupler compound was dissolved in 300 ml of N, N-dimethylformamide to give a coupler solution. 2,
1.4 g of 7-diaminofluorenone was added to 3.5% of 35% hydrochloric acid.
after suspending at 60 ° C for 30 minutes.
At 0 ° C., a solution of 1.4 g of sodium nitrite dissolved in 6 ml of water was added dropwise. After stirring at 0 ° C. for 1 hour, insolubles were removed and 15 ml of 42% borofluoric acid was added. The precipitate was dried and dried to obtain diazonium borofluoride 2.4.
g was obtained. 2.4 g of the obtained diazonium borofluoride
Was added to the above coupler liquid at 5 ° C. or lower, and the mixture was stirred for 10 minutes. Then, a solution of 1.9 g of sodium acetate dissolved in 20 ml of water was added at 10 ° C. or lower, and the mixture was stirred for 30 minutes, then returned to room temperature and stirred for 3 hours. Add 10 ml of acetic acid and add
-Washed in the order of dimethylformamide, acetone, methanol and water. Dry to 3.6 g of black powder (melting point 270)
℃ or more). This was confirmed to be Exemplified Compound No. 4 by elemental analysis and infrared absorption spectrum. Elemental analysis value: C ₅₁ H ₃₄ N ₈ O ₅ Cl ₂ Calculated value of CH N Cl (%) 67.32 3.77 12.32 7.80 Actual value (%) 66.92 3.50 13.007 .71

Example 1 0.5 parts of a polyester resin (trade name “Vylon 200” manufactured by Toyobo), 0.5 parts of Exemplified Compound No. 4 and 50 parts of tetrahydrofuran were ground and mixed by a ball mill, and the obtained dispersion was It was applied to an aluminum plate using a wire bar and dried at 80 ° C. for 20 minutes to form a charge generation layer of about 1 μm. On this charge generation layer, the following structural formula

Embedded image 1 part of hydrazone compound represented by the formula, polycarbonate resin (trade name “Panlite K-1300” manufactured by Teijin Chemicals Ltd.)
A solution prepared by dissolving 1 part in 10 parts of chloroform was applied using a wire bar, and dried at 80 ° C. for 30 minutes to obtain a layer having a thickness of about 18 parts.
A charge transport layer having a thickness of μm was formed to produce a laminated photoreceptor shown in FIG. An electrostatic copying paper testing apparatus is charged by corona discharge of the applied voltage -6KV photoreceptor using (Ltd. Kawaguchi Denki Seisakusho Model EPA-8100), to measure the surface potential V _o of that time, the dark followed by a two second And the surface potential V ₂ at that time is measured.
the surface potential is irradiated with light from a halogen lamp (color temperature 2856 ° K) in a state in which the lux measures the time becomes half of V _2, calculate the half decay exposure E1 / 2 (lux · sec) did. The surface potential V ₁₂ after 10 seconds of light irradiation, that is, the residual potential was measured.

Examples 2 to 20 The compound of the present invention was used as a charge generating material, and (CT-1) (Formula 15) and the following structural formula (Formula 1) were used as charge transport materials.
A photoreceptor was prepared in the same manner as in Example 1 using each of the compounds represented by 6), and E1 / 2 was determined. The charge generating materials, charge transporting materials and E1 / 2 used are shown in Tables 7 and 8 together with Example 1.

Embedded image

[0030]

[Table 7]

[Table 8]

Comparative Example 1 The following structural formula described in JP-B-55-42380

Embedded image A photoconductor was prepared in the same manner as in Example 1, except that the disazo compound represented by the formula (1) was used as a charge generating material, and the above (CT-4) was used as a charge transporting material. E1 / 2 is 12.0 (lu
x · sec).

Example 21 The photoreceptor prepared in Example 1 was mounted on a commercially available electrophotographic copying machine and copied, and a clear image faithful to the original image without fog was obtained even on the 10,000th copy. As described above, it can be said that the electrophotographic photoreceptor using the azo compound of the present invention has high sensitivity, stable performance for repeated use, and excellent durability. The photoreceptor of the present invention can be used not only in an electrophotographic copying machine but also in various printers and electrophotographic plate making systems that apply the principle of electrophotographic copying.

[0033]

The azo pigment of the present invention can be used in a laser beam printer or a light emitting diode printer (LE).
It is a charge generating agent showing excellent sensitivity and durability when used in D).

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration example of a photoconductor for electrophotography.

FIG. 2 is a cross-sectional view showing another configuration example of the electrophotographic photosensitive member.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conductive support 2 charge generating material 3 charge transporting material 4, 4 ′ photosensitive layer 5 charge transporting layer 6 charge generating layer

Continuation of the front page (51) Int.Cl. ⁶ identification code FI G03G 5/06 350 G03G 5/06 350 354 354 367 367 (58) Field surveyed (Int.Cl. ⁶ , DB name) C09B 35/00- 35/64 G03G 5/06 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. A compound of the general formula (I) [Formula (I) medium-Ar ¹ represents a divalent to tetravalent linking group, Ar ²
Represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aromatic heterocyclic ring, and X is necessary for forming an aromatic hydrocarbon ring or an aromatic heterocyclic ring by condensing with a benzene ring. Represents an organic residue, R represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aromatic hydrocarbon, a substituted or unsubstituted aromatic heterocyclic ring, and Y ¹ represents -CO-, -COO
-, -CONH-, wherein Y ² is -NH-, -NH
CONH-, -NHCSNH-, -NHNH-, Y ³ represents a hydrogen atom or an OH group, and n represents an integer of 2 to 4]. 2. A photoreceptor comprising the charge generating compound represented by the general formula (I) (formula 1) according to claim 1. 3. The photoconductor according to claim 2, wherein the photoconductor comprises a charge transport layer and a charge generation layer, and wherein the charge generation material of the general formula (I) (Formula 1) is contained in the charge generation layer. .