JPH04122946A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the photosensitive body having a high sensitivity and less residual potential by adding sodium acetate to a charge generating layer contg. an azo compd. CONSTITUTION:Aluminum, copper, etc., are used as a base 1 and the fine particles of he azo compd. and the sodium acetate are dispersed into a soln. dissolved with a binder. This soln. is applied on the base 1 and is dried, by which the charge generating layer 2 is obtd. A soln. dissolved with a charge transfer material and a binder is applied thereon and is dried, by which a charge transfer layer 3 is produced. Polystyrene, polacrylamide, etc., are used as the binder. The thickness of the layer 2 is preferably 0.01 to 5mum and the thickness of the layer 3 is preferably 3 to 50mum. The ratio of the azo compd. in the layer 2 is specified to >=30wt.T and the amt. of the sodium acetate to be used is specified to 5 to 1000 pts. wt. per 10000 pts. wt. azo compd. The charge transfer material is incorporated at 10 to 95wt.% into the layer 3. Since the sodium acetate is added into the charge generating layer, the sensitivity is greatly improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor necessary for copying and recording information.

[Conventional technology]

The technology of using an Ab compound in the charge generation layer of an electrophotographic photoreceptor is disclosed in JP-A-54-22834 and JP-A-60153.
050, JP-A-60-163048, JP-A-63-2
64762 and the like. However, photoreceptors using any of the Ab compounds were inferior in sensitivity compared to selenium-based photoreceptors.

[Problems to be Solved by the Invention] An object of the present invention is to create a highly sensitive electrophotographic photoreceptor.

[Means for Solving the Problem] As a result of intensive studies to solve the above-mentioned yAB, the present inventors found that adding sodium acetate to the charge generation layer of a laminated electrophotographic photoreceptor significantly increases the sensitivity. The present invention was based on the discovery that this can be improved.

That is, the present invention relates to a laminated type electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer, in which the charge generation layer contains an ab compound and sodium acetate.

The electrophotographic photoreceptor of the present invention contains an Ab compound, particularly the following -
Numerical formula (I) [wherein, Ar' represents a divalent to tetravalent aromatic linking group, Y
represents a hydrogen atom, a hydroquine group, an amino group, an aromatic amino group, a carbamoylamino group, an aromatic aminocarbonylamino group, an aliphatic amino group, and χ represents an aromatic hydrocarbon ring or an aromatic heterocarbon ring by condensing with a benzene ring. represents an organic residue forming a ring, R represents a hydrogen atom, a halogen atom, a hydroxyl group, and n represents an integer of 2 to 4] ,000 parts by weight and resin 5,000 to 20.00
A charge generation layer is created by mixing 1 part of the cap in a suitable dispersion solvent, dispersing it into fine particles, and applying the coating liquid to a conductive support.
Subsequently, a coating liquid containing a charge transport substance and a resin is applied thereon to form a charge transport layer.

A typical configuration of such a photoreceptor is shown in FIG. That is, for electrophotography, a laminated type photosensitive layer 4 comprising a charge generation layer 2 in which a charge generation substance is dispersed in a binder and a charge transport layer 3 in which a charge transport substance is dispersed in a binder is provided on a conductive support 1. 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. 1, 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.

In the present invention, known Abu compounds can be used as the Abu compound contained in the charge generation layer, but in particular -
Azo compounds of formula (I) are preferred.

In general formula (I), the divalent to tetravalent aromatic linking group represented by Ar' represents a substituted or unsubstituted aromatic hydrocarbon ring or aromatic heterocycle that may be bonded via a bonding group. However, aromatic hydrocarbon rings include benzene, naphthalene, anthracene, pyrene, phenanthrene, fluorene, anthraquinone, fluorenone, benzanthrone, etc., and aromatic heterocycles include thiophene, dibenzothiophene, pyridine, carbazole, benzoxazole, Examples include benzothiazole.

In addition, when having a substituent, examples of the substituent include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group,
Alkoxy groups such as methoxy groups, aryl groups such as phenyl groups and naphthyl groups, substituted amino groups such as diethylamino groups and diphenylamino groups, halogen atoms such as fluorine atoms, chlorine atoms, and bromine atoms, hydroxyl groups, nitro groups, cyano groups, etc. can be mentioned. Further, the aromatic hydrocarbon ring and the aromatic heterocycle may be bonded via a bonding group,
Examples of the bonding group include -o--s--co-CH=CH.

Ar that can be preferably used in the present invention is as follows: A specific example is given below.

When n=2 C.B.

(, A-8) (A-9) When n = 3 When n = 4 (A-15) Specifically, X in general formula (I) is fused with the benzene ring to which the Ab group is bonded. Hydrocarbon rings such as naphthalene rings and anthracene rings, indole rings, carbazole rings,
Examples include those forming a heterocycle such as a penducarbazole ring and a dibenzofuran ring, and a naphthalene ring is particularly preferred as the ring formed. 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. Ab compounds that can be preferably used in the present invention are specifically shown in Tables 1 to 3.

In addition, in the table, in Ar' (A-1) to (A-15)
is the structural formula shown above.

In the present invention, particularly preferred Ab compounds are compounds represented by the general formula (It) (II) [In the formula (II), Y represents the same meaning as the general formula (I)].

The azo compound that can be used in the present invention can be synthesized by a known method as follows.

-Math (TV) Ar'(-NHZ). (TV) [In the formula, Ar' and n represent the same meanings as in general formula (I)] After diazotizing the amine represented by and then isolating the diazotized compound as it is or as a borofluoride salt, - It can be produced into a container by force pulling with a coupler compound represented by formula (V) [wherein R, X and Y have the same meanings as in general formula (I)].

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, examples of hole-transporting substances include polymers containing heterocyclic compounds such as poly-N-vinylcarbazole, and triazoles. derivatives, oxadiazole derivatives, imidazole derivatives, birapurin derivatives, polyarylalkane derivatives, phenylenediamine derivatives,
Examples include electron-donating substances that easily transport holes, such as hydrazone derivatives, amino-substituted chalcone derivatives, triarylamine derivatives, carbazole derivatives, and stilbene derivatives.

For example, 9-ethylcarbazole-3-aldehyde-
1-Methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde-1benzyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde-1,1-diphenylhydrazone, 4”-(4゛-diphenyl Amino-α-phenylstyryl)aldehyde-1,
1-; phenylhydrazone, 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 11-diphenylhydrazone, 4-methoxybenzaldehyde-1-benzyl-1-(4-methoxy)phenylhydrazone, 4-diphenylaminobenzaldehyde-1-benzyl-1-phenylhydrazone, 4-diphenylaminobenzaldehyde-1-benzyl-1-phenylhydrazone, Hendylaminobenzaldehyde-1,1-diphenylhydrazone, 1,1-bis(4-dihendylaminophenyl)propane, tris(4-diethylaminophenyl)methane, 11-bis(4-dihendylaminophenyl)propane , 2,2'-dimethyl-44'-bis(diethylamino)-triphenylmethane, 9-(4-diethylaminostyryl)anthracene, 9-from1O-(
4-diethylaminostyryl)anthracene, 9-(4
-dimethylaminostylidene)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-diphenylaminostilbene, 4-dibenzylaminostilbene, 4-ditolylaminostilhene, 1(4-diphenylaminostyryl) Naphthalene, 1-(4-diethylaminostyryl)naphthalene, 4°-diphenylamino-α
-phenylstilhene, 4'-methylphenylamino-
α-Phenylstilbene, 1-phenyl-3-(4-diethylaminostyryl 15-(4-diethylaminophenyl) birapurine, 1-phenyl-3-(4-dimethylaminostyryl)-5-(4-dimethylaminophenyl) birapurine and so on.

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-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)-98-4santhene, poly-N-vinylecarhasol, halogenated poly-N-vinylhydrazole, polyvinylpyrene, polyvinylanthracene, pyrene formaldehyde resin, ethyl carbadul formaldehyde resin, etc.

Examples of electron transport substances include chloranil, fromanil, tetrasoanoethylene, tetracyanoquinodimethane, 2,4.7-)Lielow 9 fluorenone, 2
．． 4,5.7-tetranitro-9 fluorene, 2,45
．． 7-titranitroxanthone, 2.4.8-)linitrothioxanthone, 2,6.8-trinitro-4H-
Indeno(I,2-b)thiophen-4-one, 1,3
．． 7-) Linitrodibenzothiophene-5,5-dioxide and the like.

These charge transport materials may be used alone or in combination of two or more.

As the charge transport material used in the present invention, in particular, - formula (I
II) [In formula (I[l), A r '' + A r ' +^
(r4 represents an alkyl group, an aromatic hydrocarbon group, or an aromatic heterocyclic group, and m represents an integer of 1 to 3) A compound represented by the following is preferable.

The electrophotographic photoreceptor of the present invention contains an Ab compound, especially the formula (
+) azo compounds, sodium acetate and charge transport substances,
It is composed of a binder, a conductive support, etc., and other components of the photoreceptor are not particularly limited as long as they function as components of the photoreceptor.

That is, the conductive support used in the photoreceptor of the present invention includes a metal plate made of aluminum, copper, zinc, etc., a plastic sheet or film made of polyester, etc., on which a conductive material such as aluminum or 5n02 is vapor-deposited, or Conductive treated paper, resin, etc. are used.

As binders, vinyl polymers such as polystyrene, polyacrylamide, and poly-N-vinylcarbazole, and condensation resins such as polyamide resins, polyester resins, Yupoquin resins, phenoxy resins, and polycarbonate resins are used. Any resin that is adhesive to the body can be used.

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 part m or less. preferable.

Conventionally known methods can be used to manufacture the photoreceptor. For example, fine particles of an azo compound and sodium acetate are dispersed in a solution containing a binder, coated on a conductive support, and dried to obtain a charge ordering layer. A charge transport layer can be produced by coating and drying. Other methods can also be used to make the charge generating layer. For example, there is a method in which sodium acetate is added to a solution of an azo compound, then applied and dried.
-S has drawbacks in production, such as the use of organic amines such as ethylenediamine and n-butylamine that are difficult to handle, so a coating method using a fine particle dispersion of an azo compound is preferred. Application is carried out by conventional means, such as doctor blade, dipping, wire bar, etc. The optimal range of the thickness of the photosensitive layer differs depending on the type of photoreceptor.

In the photoreceptor shown in FIG. 1, the thickness of the charge generation layer 2 is preferably 0.01 to 5 μm, more preferably 0.01 to 5 μm.
05-2 μm. If the thickness is less than 0.01 μm, charge generation will not be sufficient, and if it exceeds 5 μm, the residual potential will be high and it is not preferred for practical use.

The thickness of the charge transport layer 3 is preferably 3 to 50 .mu.m, more preferably 5 to 30 .mu.m. If the thickness is less than 3 .mu.m, the amount of charge will be insufficient, and if it exceeds 50 .mu.m, the residual potential will be undesirably high.

- The content of the Ab compound represented by the formula (I) in the photosensitive layer varies depending on the type of photoreceptor, but in the photoreceptor shown in FIG. 1, the proportion of the Ab compound in the charge generation layer 2 is preferable. is 30% by weight or more, more preferably 50% by weight or more. The amount of sodium acetate used is Abu compound 10,00
The amount is 5 to 1000 parts by weight relative to 0 parts by weight. Further, the charge transport layer 3 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.

〔Effect of the invention〕

In the present invention, by adding sodium acetate to the charge generation layer containing an azo compound, it is possible to provide an electrophotographic photoreceptor with high sensitivity and low residual potential.

〔Example〕

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples, but the embodiments of the present invention are not limited thereby.

Example 1 200 parts of the Abu compound of Exemplary Compound No. 3 in Table 1 represented by the following formula (A) (A), 1 part of polyester resin (trade name) 20 parts
0'' manufactured by Toyobo), 0.5 part of sodium acetate, 6000 parts of cyclohexanone, and 1000 parts of glass peas were shaken using a shaker. Then remove the glass peas,
A coating liquid was obtained.

The coating liquid was applied to an aluminum plate and dried. The thickness of the obtained charge generation layer was 0.7 μm.

Next, 100 parts of a compound represented by the following formula (B), polycarbo a, -) resin (
Product name: Panlight 11300J (made by Teijin Kasei) 100
The sample was dissolved in chloroform and laminated on the charge generation layer on the aluminum plate. The thickness of the charge transport layer was 20 μm.

In the manner described above, an electrophotographic photoreceptor as shown in FIG. 1 was produced.

Regarding this electrophotographic photoreceptor, the electrostatic copying paper tester (
(2) Using a model EPA-8100 manufactured by Rotm Seisakusho, the surface potential at that time was measured by corona discharge at an applied voltage of -6 KV, and then left in a dark place for 2 seconds. , was measured. Next, with the surface illuminance of the photoreceptor at 51 ux, light from a halogen lamp C (color temperature: 2 days, 56°K) was irradiated to raise the surface potential to V! 1
/2 is measured, and the half-reduction exposure amount E 1/2 (I
ux-see) was calculated. Also, the surface potential Vl after 10 seconds of light irradiation! , that is, the residual potential was measured. As a result, the sensitivity is E 1/2 = 1.1 1ux-secV lz
-5V.

Production Example 1 [Production of compound of formula (A)] 1.4 g of 2.7-diamitsufluorenone was dissolved in 35% hydrochloric acid 3
．． 5d and water 45ad! After incubating at 60°C for 30 minutes, add 1.4g of sodium nitrite to 60ml of water at 0°C.
The solution dissolved in tri was added dropwise. ft for 1 hour at 0°C
After stirring, insoluble matter was removed and 42% 2% borofluoric acid was added.
Added 5d. The precipitated crystals were filtered and dried to obtain 2.4 g of diazonium borofluoride salt.

Dissolve 2.0 g of 2-hydroquine-3-formylnaphthalene in 200 d of N,N-dimethylformamide and heat at 0 to 5°
Cooled to C. 2.0 g of the diazonium borofluoride salt
was added and stirred for 5 minutes. A solution of 1.6 g of sodium acetate dissolved in 30 d of water was added dropwise at 0 to 5°C. After stirring at the same temperature for 30 minutes, the mixture was stirred at room temperature for 4 hours. The formed precipitate was filtered and washed successively with N,N-dimethylformamide, acetone, methanol, and water. After drying, 1.7 g of black powder was obtained.

The melting point was above 270°C.

The obtained compound was confirmed to be exemplified compound Nα3 based on elemental analysis values and infrared absorption spectrum.

Elemental analysis value CHN Calculated value (%) 72,92 3.47 9.72 Real 7Ely1y (%) 72.47 3,36
9.54 Infrared absorption spectrum of this compound (KB
r method) is shown in Figure 2.

Comparative Example 1 0.5 parts of polyester resin (trade name "Vylon 200" manufactured by Toyobo), 0.5 parts of compound (A) and 50 parts of cyclohexanone were ground and mixed in a ball mill, and the resulting dispersion was placed on an aluminum plate. Apply using wire bar, 80℃
This was dried for 20 minutes to form a charge generation layer of 0.7 μm. A charge transport layer was formed on this charge generation layer in the same manner as in the example.

The sensitivity of this electrophotographic photoreceptor is E 1/2 = 31ux-sec V+z　　-20V Met.

Example 2 Exemplary compound No. shown by the following formula (C), 200 parts of compound 1B, 5 parts of sodium acetate, polyester resin (trade name "Vylon 2")
00'' manufactured by Toyobo) 200 parts, tetrahydrofuran 200
00 parts were pulverized and mixed in a ball mill, and the resulting dispersion was applied to an aluminum plate using a wire bar and dried.
A charge generation layer of .mu.m was formed.

A solution prepared by dissolving 1 part of the compound of formula (B) and 1 part of polycarbonate resin (trade name "Panlight ni-1300" manufactured by Kijin Kasei Co., Ltd.) in 10 parts of chloroform was applied onto this charge generation layer using a wire bar. It was dried at .degree. C. for 30 minutes to form a charge transport layer with a thickness of about 18 .mu.m, thereby producing the laminated electrophotographic photoreceptor shown in FIG. 1.

The sensitivity of this photoreceptor is E 1/2 =0.61ux-sec■1□ =I
It was V.

Production Example 2 [Production of compound of formula (C)] 2-Hydroxy-3-naphthalenecarboxylic acid chloride 9
．． 0 g and 5.2 g of 4-methyl-7-amino-coumarin,
Toluene 501 T) IP40al! were mixed, and 3.63 g of dimethylaniline was added dropwise while stirring.

After reacting for 3 hours at 80-906, 1,3. dimethyl-
2 Add 20m of imidazolidinone (DMI),
The reaction was carried out at 0 to 90°C for 8 hours. After cooling to room temperature, 30 sheets of water were added. It was filtered, washed with methanol, and dried to obtain 6.1 g of the compound of the following formula.

5.0 g of this coupler compound was dissolved in 300 d of N,N-dimethylformamide to obtain a coupler liquid.

2.7-Diamitsufluorenone 1.4g 35% hydrochloric acid 3
．． After stirring for 1 hour at 0°C, a solution of 1.4 g of sodium nitrite dissolved in 6 d of water was added dropwise at 0°C. The material was removed, and 42% fluoroboric acid 15- was added.The precipitated crystals were 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 Camplar solution at a temperature below 5"C and stirred for 10 minutes. Then, 9 g of the diazonium borofluoride salt was dissolved in 20 d of water.
The solution was added at a temperature below 10°C, stirred for 30 minutes, then returned to room temperature and stirred for 3 hours. Add 10 d of acetic acid, filter, N, N
- Washed with dimethylformamide, acetone, methanol, and water in this order. Dry to give 3.6 g of black powder (melting point 270
°C or higher). This product was confirmed to be Exemplified Compound 18 based on elemental analysis values and infrared absorption spectrum.

Elemental analysis value CHN Calculated value (%) 71.59 3,71 9.11 Actual value (%) 71.20 3.62 9.08 The infrared absorption spectrum (KBr method) of this compound is shown in FIG.

Comparative Example 2 Polyester resin (“Vylon 200J”) 0.5
0.5 parts of (I,1Fl(C)) 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 at 80°
It was dried for 20 minutes at C. to form a charge generation layer with a thickness of about 1 μm. A charge transport layer was formed on this charge generation layer in the same manner as in Example 2. The sensitivity of the photoreceptor obtained is E 1/2 = 1.51ux-secV+z
=20V.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the structure of an electrophotographic photoreceptor. In FIG. 1, the respective symbols are as follows. 1--1 Conductive support 2--1 Charge generation layer 3--1 Charge transport layer 4-1 Photosensitive layer FIG. 2 shows the infrared absorption spectrum of exemplary compound N083 (
KBr method). FIG. 3 shows the infrared absorption spectrum (KBr method) of Exemplary Compound No. 18. Patent applicant: Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Scope of Claims] 1) A laminated type electrophotographic photoreceptor comprising a charge generation layer and a charge transport layer, characterized in that the charge generation layer contains an azo compound and sodium acetate. 2) The azo compound contained in the charge generation layer has the following general formula (
I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In formula (I), Ar^1 represents a divalent to tetravalent aromatic linking group, and Y represents a hydrogen atom, hydroxyl group, amino group, carbamoyl Amino group, aliphatic amino group, aromatic amino group,
represents an aromatic aminocarbonylamino group; represents an integer from 2 to 4] The electrophotographic photoreceptor according to claim 1, which is a compound represented by the following formula. 3) The azo compound contained in the charge generation layer has the following general formula (I
I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (II) (In formula (II), Y is a hydrogen atom, hydroxy group, amino group, carbamoylamino group, aliphatic amino group, aromatic amino group, aromatic amino The electrophotographic photoreceptor according to claim 1, wherein the electrophotographic photoreceptor is a compound represented by: The electrophotographic photoreceptor according to claim 1, which is 000). 5) The charge transport substance contained in the charge transport layer has the following general formula (III) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (III) [In formula (III), Ar^2, Ar^3, Ar^4 represents an alkyl group, an aromatic hydrocarbon group, an aromatic heterocyclic group,
The electrophotographic photoreceptor according to claim 3, which is a compound represented by the following formula: m represents an integer of 1 to 3.