JPH04225068A - Azo compound and sensitizing substance using the same compound - Google Patents

Abstract

PURPOSE:To obtain a new azo compound which is an electron charge generating substrate suitable for an organic photosensitive substance for printer by light- emitting diode or laser rays, and having high sensitivity and high durability. CONSTITUTION:A compound expressed by formula I {Ar<1> is 2-4 valent coupling group; Ar<2> is (substituted)aromatic hydrocarbon, (substituted)aromatic heterocyclic ring, CONHR', CSNHR', NHR' [R' is (substituted)aromatic hydrocarbon]; X is oragnic group to form aromatic hydrocarbon or aromatic heterocycle by condensing with a benzene ring; R is (substituted)alkyl, aromatic hydrocarbon or (substituted)heterocycle; Y<1> is CO, COO, CONH; Y<2> is NH, NHCONH, NHCSNH OR NHNH; Y<3> is H or OH; (n) is 2-4}. The above-mentioned compound is produced by obtaining a coupler compound expressed by formula II from 2-acetylaminonaphthalene-3-carboxylic acid, etc., and adding a diazonium boron fluoride salt to the intermediate compound followedly adding an aqueous solution of sodium acetate thereto, stirring and washing the mixture with an acid.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel compound that can be used in a photoreceptor, and a photoreceptor using the same 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 photoreceptors. However, photoreceptors using these photosensitive materials do not fully satisfy the performance requirements for electrophotographic photoreceptors, such as sensitivity, photostability, moisture resistance, and durability. For example, a photoreceptor using a selenium-based material has excellent sensitivity, but the characteristics of the photoreceptor tend to deteriorate due to crystallization due to heat or adhesion of dirt. Furthermore, since it is manufactured by vacuum deposition, it is expensive, and it also has many drawbacks, such as being difficult to process into a belt shape because it is not flexible. Photoreceptors using cadmium sulfide-based materials have problems in moisture resistance and durability, and photoreceptors using zinc sulfide have problems in durability.

In order to overcome the drawbacks of photoreceptors using these inorganic photosensitive materials, various studies have been made on photoreceptors using organic photosensitive materials. For example, a combination of 2,4,7-trinitro-9-fluorenone and polyN-vinylcarbazole is known as an organic photosensitive material that has been partially put into practical use. However, photoreceptors using this method had low sensitivity and were not satisfactory in terms of durability.

In recent years, among photoreceptors developed to improve the above-mentioned drawbacks, a functionally separated photoreceptor in which charge generation function and charge transport function are shared by separate substances has been attracting attention. In this functionally separated type photoreceptor, materials having respective functions can be selected from a wide range of materials and combined, so that it is possible to produce a photoreceptor with high sensitivity and high durability. Many materials have been proposed as charge generating materials for use in such functionally separated photoreceptors. Among these, photoreceptors using organic dyes or organic pigments as charge-generating substances have attracted particular attention in recent years. For example, a photoreceptor using a disazo pigment having a styryl stilbene skeleton (Japanese Patent Application Laid-Open No. 53-133445), a photoreceptor using a disazo pigment having a carbazole skeleton (Japanese Patent Application Laid-Open No. 53-95033), triphenylamine Photoreceptor using trisazo pigment with skeleton
132347), a photoreceptor using a disazo pigment having a distyrylcarbazole skeleton (Japanese Patent Application Laid-Open No. 54-14
967), a photoreceptor using a disazo pigment having a bisstilbene skeleton (Japanese Unexamined Patent Publication No. 17733/1983)
etc. have been reported. However, these photoreceptors for electrophotography do not necessarily fully satisfy the required performance, especially when the light source is a semiconductor laser (650 to 850 nm).
) and LEDs (600 to 700 nm), they had the drawback of extremely poor sensitivity.

[0005]

[Problems to be Solved by the Invention] An object of the present invention is to have sufficient sensitivity when using a semiconductor laser or LED as a light source;
Another object of the present invention is to provide a charge generating agent with excellent durability and a photoreceptor using the same.

[0006]

[Means for Solving the Problems] The present inventors have made extensive studies in order to solve the above problems, and as a result, the above general formula (
It has been discovered that the azo compound represented by I) (Chemical formula 1) provides an electrophotographic photoreceptor having excellent properties such as high sensitivity and high durability, and the present invention has been achieved.

Examples of the divalent to tetravalent linking group represented by Ar1 in the general formula (I) include benzene, naphthalene, anthracene, pyrene, phenanthrene, fluorene, biphenyl, anthraquinone, fluorenone, benzanthrone, thiophene, dibenzothiophene, and pyridine. ,
Carbazole, benzoxazole, benzothiazole

[Chemical formula 2] etc. In addition, when it has a substituent, the substituent includes an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an alkoxy group such as a methoxy group, an aryl group such as a phenyl group or a naphthyl group, a diethylamino group, or a diphenyl group. Examples include substituted amino groups such as amino groups, halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms, hydroxyl groups, nitro groups, and cyano groups.

Ar1 which can be preferably used in the present invention
A specific example is given below. When n=2

[Chemical formula 3]

[C4] When n=3

[C5] When n=4

[Image Omitted] Particularly preferable linking groups for use in semiconductor laser light sources and LED light sources are (A-3), (A-6), and (A-7).
, (A-10), (A11), (A-12), (A-1
3), (A-14), (A-15) and the following formula (A-16
).

embedded image [The groups represented by Z1 and Z2 in formula (A-16) are
Represents nitrile, alkoxycarbonyl, trifluoromethyl]

[0009] In Ar2, examples of aromatic hydrocarbon rings include benzene, naphthalene, anthcene, anthraquinone, pyrene, phenanthrene, fluorene, and fluorenone, and examples of aromatic heterocycles include thiophene,
Examples include furan, pyridine, carbazole, indole, quinoline, benzofuran, dibenzofuran, and coumarin. In addition, when it has a substituent, the substituent is an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a chlorine atom, a fluorine atom, or a bromine atom. Examples include halogen atoms such as, halomethyl groups such as trifluoromethyl groups, dialkylamino groups such as dimethylamino groups and diethylamino groups, nitro groups, cyano groups, carboxyl groups, and esters thereof. Also, X
Specific examples include hydrocarbon rings such as naphthalene rings and anthracene rings formed by condensation with a benzene ring to which an azo group is bonded, and heterocycles such as indole rings, carbazole rings, benzocarbazole rings, and dibenzofuran rings. ,
A naphthalene ring is particularly preferred. Further, 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 azo compounds that can be preferably used in the present invention are shown in Tables 1 to 6 below. In addition, in the table, Ar1
In (A-1) to (A-16) represent the structural formulas exemplified above. The general formulas of the compounds shown in Tables 1 to 3 are shown below.

[Chemical formula 8]

[Table 1]

[Table 2]

[Table 3]

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

[Chemical formula 9]

[Table 4]

[Table 5]

[Table 6]

The compounds of the present invention can be synthesized using the following method. Organic Synthesis Coll
active Vol. III, p. 78-p. 8
It was synthesized according to 2. The following formula (II) (Chemical formula 10)

[Chemical 1
0] The following formula (III) (Chemical formula 11) is obtained by broadly acylating the compound with an acid halide etc.

[Formula (III), R, Y1, Y3 are general formula (I) (
It has the same meaning as R, Y1, Y3 in Chemical formula 1). ] with thionyl chloride, PCl3, POCl3, etc., and then Ar2 Y2 -H[Ar2, Y
2 represents the same meaning as in general formula (I). ] to form the formula (IV)

[Formula (IV), R, Y1 , Y2 , Y3 , Ar2
, X represent the same meaning as in general formula (I). ] was obtained.

General formula (V) (Chemical formula 13)

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

The electrophotographic photoreceptor of the present invention has the general formula (I)
The photosensitive layer on the conductive support contains at least one of the azo compounds represented by the following as a charge generating substance. A typical configuration of such a photoreceptor is shown in FIGS. 1 and 2. What is shown in FIG. 1 is a photoreceptor in which a dispersion type photosensitive layer 4 in which a charge generating substance 2 and a charge transporting substance 3 are dispersed in a binder is provided on a conductive support 1. A laminated type photosensitive layer 4' was provided on a conductive support 1, comprising a charge generation layer 6 in which a charge generation substance 2 was dispersed in a binder, and a charge transport layer 5 in which a charge transport substance 3 was dispersed in a binder. It is a photoreceptor. Other examples include those in which the charge generation layer and 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, imagewise exposed light passes through the charge transport layer, and a charge generation substance generates charges in the charge generation layer. The generated charges are injected into the charge transport layer, and the charge transport material performs the transport.

The electrophotographic photoreceptor of the present invention has the general formula (I
) in addition to the azo compound, a conductive support, a binder, a charge transport substance, etc., and other components of the photoreceptor are not particularly limited as long as they function as components of the photoreceptor. Not done. That is, the conductive support used in the photoreceptor of the present invention includes aluminum,
Aluminum, Sn on metal plates such as copper and zinc, plastic sheets or plastic films such as polyester, etc.
A material on which a conductive material such as O2 is vapor-deposited, or paper, resin, or the like that has been subjected to conductive treatment is used.

As the binder, vinyl polymers such as polystyrene, polyacrylamide, poly-N-vinylcarbazole, polyamide resins, polyester resins,
Condensation resins such as epoxy resins, phenoxy resins, and polycarbonate resins are used, but any resin that is insulating and has adhesiveness to the support can be used.

Charge transport materials are generally classified into two types: hole transport materials and electron transport materials, and both can be used in the photoreceptor of the present invention. In addition to electron-accepting substances that easily transport electrons, such as trinitrofluorenone or tetranitrofluorenone, hole-transporting substances include
Polymers containing heterocyclic compounds such as poly-N-vinylcarbazole, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, hydrazone derivatives, amino-substituted chalcone Examples include electron-donating substances that easily transport holes, such as derivatives, triarylamine derivatives, carbazole derivatives, and stilbene derivatives.

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-dibenzylaminophenyl)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-diphenylaminostyrylbene, 4-dibenzylaminostyrylbene, 4-ditolylaminostyrylbene, 1-(4-diphenylaminostyryl)naphthalene, 1-(4-diethylaminostyryl)naphthalene, 4 '-Diphenylamino-α-phenylstilbene, 4'-methylphenylamino-α-phenylstilbene, 1-phenyl-3-(4-diethylaminostyryl)-5-(4-diethylaminophenyl)pyrazoline, 1-phenyl-3 -(4-dimethylaminostyryl)-5-(4-dimethylaminophenyl)pyrazoline, etc.

Other hole transport 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-ethylcarbazole-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, pyrene formaldehyde resin , ethyl carbazole formaldehyde resin and the like.

Examples of the charge transport substance include chloranil, bromoanil, 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]thiophene-
4-one, 1,3,7-trinitrodibenzothiophene-5,5-dioxide, and the like. These charge transport materials may be used alone or in a mixture of two or more.

[0022] An intermediate layer can be provided between the photosensitive layer and the conductive support if necessary, and suitable materials include polyamide, nitrocellulose, casein, polyvinyl alcohol, etc., and the film thickness is 1 μm or less. is preferred.

[0023] Conventionally known methods can be used to produce the photoreceptor. For example, in a laminated photoreceptor, fine particles of an azo compound are dispersed in a solution containing a binder, coated on a conductive support, and dried to obtain a charge generation layer. A charge transport layer can be created by coating and drying. Other methods can also be used to make the charge generating 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, but the former method is expensive, and the latter method uses organic amines that are generally difficult to handle, such as ethylenediamine and n-butylamine. Since there are some disadvantages in production, such as the above, the method of coating a fine particle dispersion of an azo compound is preferable. Application may be carried out by conventional means, such as a doctor blade, dipping, wire bar, etc. The optimal range of the thickness of the photosensitive layer differs depending on the type of photoreceptor. For example, in the photoreceptor shown in FIG. 1, the thickness is preferably 3 to 50 μm, more preferably 5 to 30 μm.

In the photoreceptor 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, sufficient charge generation is not possible, and if it exceeds 5 μm, the residual potential will be high, which is not practical. Also,
The thickness of the charge transport layer 5 is preferably 3 to 50 μm, more preferably 5 to 30 μm; if the thickness is less than 3 μm, the amount of charge will be insufficient, and if it exceeds 50 μm, the residual potential will be high and it is not practical. .

The content of the azo compound represented by the general formula (I) in the photosensitive layer varies depending on the type of photoreceptor, but in the photoreceptor shown in FIG. % or less, more preferably 20% by weight or less. In addition, this layer preferably contains a charge transport material in an amount of 10 to 95% by weight.
, more preferably in a proportion of 30 to 90% by weight. Further, in the photoreceptor shown in FIG. 2, the proportion of the azo compound in the charge generation layer 6 is preferably 30% by weight or more, more preferably 50% by weight or more. Further, the charge transport layer 5 contains a charge transport substance in an amount of 10 to 95% by weight, preferably 30 to 90% by weight. It should be noted that if the amount of the charge transport material in this layer is less than 10% by weight, hardly any charge will be transported, and if it exceeds 95% by weight, the mechanical strength of the photoreceptor will be poor, which is not preferred in practice.

[0026]

[Effects] The electrophotographic photoreceptor of the present invention uses an azo compound represented by the general formula (I) as a charge generating substance, so it is easy to manufacture, has high sensitivity, and has excellent performance that does not deteriorate with repeated use. Has performance.

[0027]

[Examples] The present invention will be specifically explained below with reference to Examples, but the embodiments of the present invention are not limited thereto. Production example 1 2-acetylaminonaphthalene-3-carboxylic acid 25g
, 15.7 g of 2-chloroaniline in 200 ml of toluene
0.1 ml of N,N-dimethylformamide,
13.4 g of phosphorus trichloride was added, and the mixture was 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 prepare a coupler liquid. 2
, 1.4 g of 7-diaminofluorenone was dissolved in 35% hydrochloric acid 3.
After suspending the mixture in 5 ml and 45 ml of water and keeping it warm at 60°C for 30 minutes, a solution of 1.4 g of sodium nitrite dissolved in 6 ml of water was added dropwise at 0°C. After stirring at 0° C. for 1 hour, insoluble materials were removed and 15 ml of 42% fluoroboric acid was added. The precipitated result was filtered and dried to obtain 2.4 g of diazonium borofluoride salt. 2.4 g of the obtained diazonium borofluoride salt was added to the above coupler liquid at 5°C or less, and 1
Stirred for 0 minutes. Next, add 1.9 g of sodium acetate to 20 g of water.
ml of the solution was added at 10° C. or below, stirred for 30 minutes, then returned to room temperature and stirred for 3 hours. 10 ml of acetic acid was added, followed by filtration and washing with N,N-dimethylformamide, acetone, methanol, and water in this order. Dry to black powder 3.6
g (melting point 270°C or higher) was obtained. Based on the elemental analysis values and infrared absorption spectrum, this compound was designated as Exemplified Compound No. It was confirmed that it was 4. Elemental analysis value C51H34N8 O5 Cl2
as
C H N
Cl calculated value (%) 67.32
3.77 12.32 7.80 Actual value (
%) 66.92 3.50 13.00 7
．． 71

Example 1 0.5 part of polyester resin (trade name "Vylon 200" manufactured by Toyobo Co., Ltd.), exemplified compound No. 4 and 50 parts of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion 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. . The following structural formula is applied on this charge generation layer.

1 part of a hydrazone compound represented by [Chemical formula 15], polycarbonate resin (trade name "Panlite K-1300" manufactured by Teijin Kasei)
A solution prepared by dissolving 1 part of chloroform in 10 parts of chloroform was applied using a wire bar, dried at 80°C for 30 minutes, and the thickness was approximately 18 cm.
A charge transport layer having a thickness of .mu.m was formed to produce a laminated photoreceptor shown in FIG. Using an electrostatic copying paper tester (Model EPA-8100 manufactured by Kawaguchi Electric Seisakusho Co., Ltd.), the photoreceptor was charged by corona discharge at an applied voltage of -6 KV, the surface potential Vo at that time was measured, and then the photoreceptor was placed in the dark for 2 seconds. Leave it in
Measure the surface potential V2 at that time, and then irradiate light from a halogen lamp (color temperature 2856°K) with the surface illuminance of the photoreceptor at 5 lux for a period of time until the surface potential reaches 1/2 of V2. The half-decreased exposure amount E1/2 (l
ux・sec) was calculated. Furthermore, the surface potential V12, ie, the residual potential, was measured after 10 seconds of light irradiation.

Examples 2 to 20 The compound of the present invention was used as a charge generating substance, and (CT-1) (Chemical formula 15) and the following structural formula (Chemical formula 16) were used as a charge transporting substance.
), photoreceptors were prepared in the same manner as in Example 1, and E1/2 was determined. The charge generating substance, charge transporting substance and E1/2 used are shown in Example 1.
They are also shown in Tables 7 and 8 below.

[Chemical formula 16]

[0030]

[Table 7]

[Table 8]

Comparative Example 1 The following structural formula described in Japanese Patent Publication No. 55-42380

A photoreceptor was produced in the same manner as in Example 1, except that the disazo compound represented by the following formula was used as the charge-generating substance and the above (CT-4) was used as the charge-transporting substance. E1/2 is 12.0
(lux sec).

Example 21 The photoreceptor produced in Example 1 was attached to a commercially available electrophotographic copying machine to make copies, and even on the 10,000th copy, a clear image faithful to the original without fogging was obtained. As described above, it can be said that the electrophotographic photoreceptor using the azo compound of the present invention has high sensitivity and stable performance upon repeated use, and is also excellent in durability. The photoreceptor of the present invention can be used not only in electrophotographic copying machines, but also in various printers, electrophotographic engraving systems, etc. that apply electrophotographic copying principles.

[0033]

Effects of the Invention The azo pigment of the present invention can be used in laser beam printers or light emitting diode printers (LED printers).
) is a charge generating agent that exhibits excellent sensitivity and durability when used in

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an example of the structure of an electrophotographic photoreceptor.

FIG. 2 is a sectional view showing another example of the structure of an electrophotographic photoreceptor.

[Explanation of symbols]

1 Conductive support 2 Charge generating substance 3 Charge transport material 4,4' Photosensitive layer 5 Charge transport layer 6 Charge generation layer

Claims (3)

[Claims] Claim 1: General formula (I) (Formula 1) [Formula (I), Ar1 represents a divalent to tetravalent linking group, and A
r2 is a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocycle, -CONHR', -CSNH
R', NHR'(R' represents a substituted or unsubstituted aromatic hydrocarbon); , represents an organic residue, R represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aromatic hydrocarbon, a substituted or unsubstituted aromatic heterocycle, and Y1 represents -CO-, -COO
-, -CONH-, and Y2 is -NH-, -N
HCONH-, -NHCSNH-, -NHNH-, Y3 represents a hydrogen atom or an OH group, and n is 2
represents an integer of ~4]. 2. A photoreceptor comprising a charge generating compound represented by the general formula (I) (Chemical formula 1) according to claim 1. 3. The photoreceptor according to claim 2, wherein the photoreceptor is composed of a charge transport layer and a charge generation layer, and the charge generation substance of general formula (I) (Chemical formula 1) is contained in the charge generation layer. .