JPH01230054A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide sufficient sensitivity to the above photosensitive body and to improve the durability thereof by incorporating a specific quinonoid compd. into the photosensitive layer on a conductive base. CONSTITUTION:The quinonoid compd. expressed by formula I is incorporated into the photosensitive layer on the conductive base. In formula I, X denotes O, S, SO, SO2, Se, Te, N-R, an A ring and C ring are unsubstd. or have <=4 substituents, a B ring is unsubstd. or has <=2 substituents; R denotes hydrogen or substituent having 1-12C; (n) denotes integer in the range of 1-5. The production is thereby facilitated and the high sensitivity is obtd.; in addition, the deterioration in the performance is obviated in spite of the iterative use.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photoreceptor for electrophotography. More specifically, the present invention relates to an electrophotographic photoreceptor in which a photosensitive layer on a conductive support contains a novel quinonoid compound as a charge generating substance.

[Prior 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 is susceptible to crystallization due to heat or adhesion of foreign matter, resulting in deterioration of the photoreceptor's characteristics.
In addition, the cost is high because it is manufactured by vacuum evaporation.
It also has many drawbacks, such as being difficult to process into a belt because it is not flexible. Photoconductors using cadmium sulfide materials have excellent moisture resistance and durability.
Photoreceptors using zinc oxide had problems with durability.

In order to eliminate the drawbacks of photoreceptors using inorganic photosensitive materials, various studies have been made on photoreceptors using organic photosensitive materials.

For example, 2, 4.
A combination of 7-dolinitro-9-fluorenone and poly-N-vinylcarbazole is known. However, photoreceptors using this method have low sensitivity;
Further, the durability was also not satisfactory.

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, making it possible to manufacture a highly sensitive and highly durable photoreceptor.

Many materials have been proposed as charge generating materials for use in such functionally separated photoreceptors.

Among these, photoreceptors using organic dyes or pigments as charge-generating substances have attracted particular attention in recent years. For example, a photoreceptor using a disazo pigment having a styrylstilbene skeleton (Japanese Patent Application Laid-Open No. 53-133445), a photoreceptor using a disazo pigment having a carbazole skeleton (Japanese Patent Laid-open No. 53-133445),
-95033), a photoreceptor using a trisazo pigment having a triphenylamine skeleton (JP-A-53-132347)
), a photoreceptor using a disazo pigment having a distyrylcarbazole skeleton (Japanese Unexamined Patent Publication No. 54-14967), a photoreceptor using a disazo pigment having a bisstilbene skeleton (Japanese Unexamined Patent Publication No. 54-17733), and the like.

However, these electrophotographic photoreceptors do not fully satisfy the required performance, and there is a desire to develop an even better photoreceptor.

[Problem to be solved by the invention]

The problem given to the inventors is to provide an electrophotographic photoreceptor that has sufficient sensitivity and good durability.
The object of the present invention is to provide a novel organic charge generating substance for use in this purpose.

[Means to solve the problem]

The inventors have conducted extensive research and consideration to solve the above problems,
As a result, the present invention was completed by discovering that the novel quinonoid compound represented by the general formula (1) is excellent as a charge generating material for electrophotographic photoreceptors6. This electrophotographic photoreceptor is characterized in that a photosensitive layer on a conductive support contains a quinonoid compound represented by the general formula (1).

The quinonoid compound used in this invention has the general formula (1)
It is a compound represented by , and consists of a skeleton containing an A ring, a B ring, and a C ring.

Ring B is a heteroatom X (X=O, S%So.

Sow, Se, 'Te, N-R), and in this B ring, n can repeat from 1 to 5. The quinonoid compound of general formula (1) will be explained in more detail.

First, the substituents of ring A, ring B, and ring C will be explained. The A ring and the C ring are unsubstituted or have 4 or less substituents, and the B ring is unsubstituted or has 2 or less substituents. An appropriate one is selected in consideration of stability, absorption wavelength range, and film formability.

- For boat fishing, in consideration of the stability of the compound and the ease of synthesis, it is more preferable that the A ring and the C ring each have two or more substituents.

Next, the types of substituents on ring A, ring B, and ring C are selected in consideration of the above effects, but in general, hydrogen,
halogen, alkyl group, ether group, thioether group,
These include amino groups, ester groups, amide groups, carbonyl groups, aryl groups, and allyl groups. Of course, quinonoid compounds substituted with substituents other than those mentioned above are also included within the scope of the present invention.

When each of the A, B and C rings is substituted with two or more substituents, they may be cyclically substituted as shown below.

When the A ring, B ring and C ring are substituted with various substituents, the types of substituents may be different or the same, and when the number of B rings is 2 or more, each The types of substituents on ring B may be the same or different.

Next, B El will be explained. The heteroatom X of ring B is 0, S, SO%S Ot, S e%T
e, NR, and are arbitrarily selected in consideration of ease of synthesis and stability, but S, NR, and ◯ are more preferred. However, R in NR is hydrogen or a substituent having 1 to 12 carbon atoms.

In addition, the repeating number of the B ring is generally n = 1 to 5, and this repeating number is closely related to the absorption wavelength range of the quinonoid compound, so that the repeating number of the B ring is closely related to the absorption wavelength range of the quinonoid compound. It is arbitrarily selected in consideration of the relationship with the light source.

A more preferable number of repetitions is n=1 to 3.

For example, if X is represented by S in the quinonoid compound of general formula (1), then the compound with n=1 (
2), the compound (3) with n=2, and the compound (4) with n=3 are as follows, respectively.

n = 1 n = 2 n = 3 (However, I and m indicate the number of substituents) In the case of n = 1 in each solution, n = around 500 to 650 nm.
In the case of 2, around 650 to 750 nm, in the case of n=3,
λmax is around 750 to 850 nm, and
Each skeleton had a very large extinction coefficient and was excellent as a charge generating material for electrophotographic photoreceptors.

The quinonoid compound used in this invention can be synthesized, for example, according to the following synthetic route.

10: tert-butyl group The electrophotographic photoreceptor of the present invention has the general formula (1
) is contained in a photosensitive layer on a conductive support as a charge generating substance. Typical configurations of such photoreceptors are shown, for example, in FIGS. 1 and 2.

That is, the photoreceptor shown in FIG. 1 is a dispersed type photoreceptor in which a charge generating material 2 and a charge transport material 3 are dispersed in a binder on a conductive support l, and the photoreceptor shown in FIG. The photoreceptor is a laminated type photoreceptor consisting of a charge generation layer 6 in which a charge generation substance is dispersed in a binder and a charge transport layer 5 in which a charge transport substance is dispersed in a binder on a magnetic support 1.

In addition, there are also 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 contains, in addition to the quinonoid compound represented by formula (1), a conductive support, a binder, a charge transport material, and the like, and other components of the photoreceptor include: Any material can be used without particular limitation as long as it functions as a component of the photoreceptor.

That is, the conductive support used in the photoreceptor of the present invention includes a metal plate made of aluminum, copper, or zinc, a polyester or other plastic sheet, or a plastic film on which a conductive material such as aluminum or SnO□ is deposited. Alternatively, conductive treated paper can be used.

As binders, vinyl polymers such as polystyrene, polyacrylamide, and poly-N-vinylcarbazole, or condensation resins such as polyamide resins, polyester resins, epoxy resins, phenoxy resins, and polycarbonate resins are used, but they have poor insulation properties. Any resin that has good adhesion 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, poly-N-
Polymers containing heterocyclic compounds such as vinyl carbazole, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, hydrazone derivatives, amine-substituted chalcone derivatives, triaryl Examples include electron-donating substances that easily transport holes, such as amine derivatives, carbazole derivatives, and stilbene derivatives.

For example, 9-ethylcarbazole-3-aldehyde-1
-Methyl-1-phenylhydrazone, 9-ethylcarbazole-3-aldehyde-1-benzyl-l-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-l-benzyl-1-phenylhydrazone, 4-dibenzylaminobenzaldehyde-1,1
-diphenylhydrazone, 1,1-bis(4-dibenzylaminophenyl)propane, tris(4-diethylaminophenyl)methane, 2,2-dimethyl-4,4
°-bis(diethylamino)-triphenylmethane,
9-(4-diethylaminostyryl)anthracene, 9
-Bromo-10-(4-diethylaminostyryl)anthracene, 9-(4-dimethylaminobenzylidene)fluorene, 3-(9-fluorenonedene)-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-dibenzylamino Stilbene, 4-ditolylaminostilbene, 1-(4-diphenylaminostyryl)naphthalene, 1-(4-diethylaminostyryl)naphthalene, 4-diphenylamino-〇-phenylstilbene,
4-methylphenylamino-α-phenylstilbene,
l-phenyl-3-(4-diethylaminostyryl)
-5-(4-diethylaminophenyl)pyrazoline, l
-Phenyl-3-(4-dimethylaminostyryl) -
5-(4-dimethylaminophenyl)pyrazoline, 9-
(3-(4-diethylaminophenyl)-2-propenylidene 1-9H-xanthine, 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-ethylcarbazolyl-3-1-5-(4
-diethylaminophenyl)-1,3,4-oxadiazole, 2-vinyl-4-(2-chlorophenyl) -
5-(4-diethylaminophenyl)oxazole, 2
-(4-diethylaminophenyl)-4-phenyloxazole, poly-N-vinylcarbazoyl, halogenated poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, pyrene formaldehyde resin,
Examples include ethyl carbazole formaldehyde resin.

Examples of electron transport substances include chloranil, bromoanil, tetracyanoethylene, tetracyanoquine dimethane, 2.4.7-1-dinitro-9-fluorenone,
2.4.5.7-tetranitro-9-fluorene, 2,
4,5.7-titranitroxanthone, 2.4.8-trinidrothioxanthone, 2.6.8-1-linitro 4H-indeno[1,2-blthiophen-4-one,
1.3.7-1nonitrodibenzothiophene-5,5
- Dioxide, etc.

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

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 preferably 1 μm or less. .

Conventionally known methods can be used to produce the photoreceptor. For example, in a laminated photoreceptor, a charge generating layer is obtained by vacuum depositing a charge generating material on a conductive support, and then a solution containing a charge transporting material and a binder is applied and dried to transport charge. You can create layers.

Other methods can also be used to make the charge generating layer. For example, a method may be adopted in which fine particles of a charge generating substance are dispersed in a solution containing a binder and then applied and dried, or a method in which a solution in which a charge generating substance is dissolved is directly applied and dried.

The application method 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. For example, in the photoreceptor shown in FIG. 1, the thickness is preferably 3 to 50μ, more preferably 5 to 30μ.

In addition, in the photoreceptor shown in FIG. 2, the charge generation layer 6
The thickness is preferably 0. O1 to 5μ, more preferably 0.05 to 2μ. This thickness is 0. If it is less than 5μ, the generation of charge is not sufficient, and if it exceeds 5μ, the residual potential is high, which is not preferred in practice. 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 is insufficient, and if it exceeds 50 μm, the residual potential is is high and is not practical.

The content of the quinonoid compound represented by the general formula (1) in the photosensitive layer varies depending on the type of photoreceptor, but in the photoreceptor shown in FIG.
It is not more than 20% by weight, more preferably not more than 20% by weight. Further, this layer preferably contains a charge transport material in a proportion of 10 to 95% by weight, more preferably 30 to 90% by weight. In addition, in the photoreceptor as shown in FIG. 2, the proportion of the quinonoid compound in the charge-generating N6 is preferably 30
It is at least 50% by weight, more preferably at least 50% by weight.

Further, the charge transport layer 5 contains a charge transport substance in a proportion of 10 to 95% by weight, preferably 30 to 90% by weight. If the amount of the charge transport material in this layer is less than 10 weight percent, hardly any charge is transported, and if it exceeds 95 weight percent, the mechanical strength of the photoreceptor is poor, which is not preferred in practice.

[Effects of the Invention] The electrophotographic photoreceptor of the present invention is easy to manufacture, has high sensitivity, and has the following features: - By using the quinonoid compound represented by formula (1) as a charge generating substance, It exhibits excellent performance with no performance deterioration even after repeated use.

[Examples] Hereinafter, the invention will be specifically explained with reference to Examples, but the scope of the invention is not limited by these Examples.

Example 1 A charge generation layer having a thickness of about 0.5 μm was formed on an aluminum substrate by vacuum evaporating a compound represented by the following formula (5).

On this charge generation layer, 1 part by weight of 9-ethylcarbazole-3-aldehyde-1-methyl-1-phenylhydrazone c represented by the formula (6), H5, and polycarbonate resin "Panlite Ni-13" were applied.
A solution of 1 part by weight of 00W J (trade name, manufactured by Yojin Kasei) dissolved in 10 parts by weight of chloroform was applied using a wire bar and dried at 80°C for 30 minutes to form a charge of approximately 20μ in thickness. A transport layer was formed to produce a laminated photoreceptor having the structure shown in FIG.

Electrostatic copying paper testing device (Rodenki EPA-8100 model)
The photoreceptor was charged by corona discharge with an applied voltage of -6KV, the surface potential VO at that time was measured, the surface potential VO was left in a dark place for 2 seconds, and the surface potential 2 was measured. Irradiate light from a halogen lamp (color temperature 2856°K) under conditions where the surface illuminance of the body is 5 lux,
Measure the time for the surface potential to reach V2, and take half-exposure ff
iE'A (lux -5ec) was calculated. In addition, the surface potential ■1°, ie, the residual potential, was measured after 10 seconds of light irradiation.

Example 2 Same as Example 1 except that a compound represented by the following formula (7) and 4°-diphenylamino-α-phenylstilbene of the formula (7) were used instead of the charge transport agent of the formula (6). A photoreceptor was prepared in the same manner, and the results of determining the EH are shown in Table 1 along with Example 1.

Example 3 9-[3-(4-diethylaminophenyl)-2- of the following formula (8) (8) was used instead of the charge transport agent of the formula (6) above.
A photoreceptor was prepared in the same manner as in Example 1 except that E! /12 is shown in Table 2 together with Example 1.

Example 4 A compound represented by the following formula (9) was used instead of the charge generating agent of the formula (5) above, and a compound represented by the formula (8) used in Example 3 was used as the charge transporting agent. A photoreceptor was prepared in the same manner as in Example 1, and the results of determining the EH are shown in Table 2 along with Example 1.

Example 5 The compound (lO) represented by the following formula was used instead of the charge generating agent in formula (5) above, and the compound (6) used in Example 1 was used as the charge transporting agent. A photoreceptor was prepared in the same manner as in Example 1, and the results of determining the EH are shown in Table 2 together with Example 1.

Example 6 Compound (11) represented by the following formula was used instead of the charge generating agent in formula (5) above, and compound (6) used in Example 1 was used as the charge transporting agent. ,
A photoreceptor was prepared in the same manner as in Example 1, and the results of determining HH are shown in Table 1 along with Example 1.

Example 7 Compound (12) represented by the following formula was used instead of that represented by formula (5) as a charge generating agent, and compound (6) used in Example 1 was used as a charge transporting agent. A photoreceptor was prepared in the same manner as in Example 1, and the results of determining the EH are shown in Table 2 along with Example 1.

Example 8 Compound (13) represented by the following formula was used as a charge generating agent in place of that represented by formula (5), and C1l (CH
*h CH3CH(C)+3) 2 A photoreceptor was prepared in the same manner as in Example 1, except that the compound (14) represented by the following formula was used as a charge transport agent, and EH
The results of the determination are shown in Table-■ together with Example 1.

Table I As described above, the electrophotographic photoreceptor using the quinonoid compound of the present invention has high sensitivity and low residual potential, and is excellent.

Furthermore, when the produced photoreceptor was attached to a commercially available copying machine and copied, a copied image that was faithful to the original and had good reproducibility was obtained.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views showing an example of the structure of an electrophotographic photoreceptor. In addition, in FIG. 1 and FIG. 2, each reference numeral is as follows. ■・・・・・・Conductive support 4.4゛・・・・・・
Photosensitive layer 2...Charge generating substance 5...
・Charge transport layer 3...Charge transport material 6...
...Charge generation layer ratio Requester Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor, characterized in that the photosensitive layer on the conductive support contains a quinonoid compound represented by the general formula (1). ▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) (Here, X is O, S, SO, SO_2, Se, Te,
NR is represented, A ring and C ring are unsubstituted or have 4 or less substituents, B ring is unsubstituted or has 2 or less substituents, and R is hydrogen or carbon Substituents having numbers 1 to 12 are indicated. Further, n represents an integer from 1 to 5. ) 2 In the quinonoid compound of general formula (1), X is S,
The electrophotographic photoreceptor according to claim 1, which is NR or O. 3 In the quinonoid compound of general formula (1), n is 1 to
The electrophotographic photoreceptor according to claim 1, which is an integer of 3. 4 In the quinonoid compound of general formula (1), ring A and C
2. The electrophotographic photoreceptor according to claim 1, wherein each ring has two or more substituents. 5 In the quinonoid compound of general formula (1), X is S,
or N-R, where n is an integer of 1 to 3, and A
Claim 1: The ring and the C ring each have two or more substituents.
The electrophotographic photoreceptor described above.