JPS61121058A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity, to reduce variation of sensitivity and acceptance potential, and light fatigue even after repeated uses, and to greatly enhance durability by forming a photosensitive film contg. a specified azo compd. CONSTITUTION:An azo compd. represented by formula I is used for a photoconductor composing the photosensitive layer of an electrophotographic sensitive body, or only its superior carrier generating ability is utilized, and another material is used for transfer of the carrier, and said azo compd. is used for the carrier generating material of a so-called functionally separated type electrophotographic sensitive body, thus permitting the obtained sensitive body to be superior in physical film property and electrophotographic characteristics, such as potential retentivity, sensitivity, and resistance to residual potential, small in fatigue deterioration after repeated uses, prevented from change of characteristics against heat and light, and capable of exhibiting stable characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION (5) Field of Industrial Application The present invention relates to a photoreceptor, and more particularly to a novel electrophotographic photoreceptor containing a photosensitive material containing an azo compound.

(B) Prior art and its problems Conventionally, electrophotographic photoreceptors have been manufactured using W! & original layer was widely known.

However, these are not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability, etc. Furthermore, due to the toxicity of selecerate/cadmium sulfide, there are restrictions in manufacturing and handling. Ta.

- 10,000, photosensitive H7I whose main component is an organic derivative compound
Nariko photographic photoreceptors with I are relatively easy to manufacture, inexpensive, easy to handle, and generally have superior thermal stability compared to selenium photoreceptors. It has many advantages such as, and has attracted a lot of attention in recent years.

Poly-N-vinylcarbazole is well known as such an organic photoconductive compound.

An electrophotographic photoreceptor having a photosensitive layer mainly composed of a charge transfer complex formed from this and a Lewis acid such as 2.4.7-trinitro-9-fluorene was published in Japanese Patent Publication No. 50-104.
One person is listed in 96. However, this photoreceptor is not necessarily satisfactory in sensitivity and durability.

10,000, laminated type or dispersed type function-separated type photoreceptors, in which the carrier generation function and carrier transport function are assigned to separate substances, have a wide selection range of materials, and have a wide range of charging characteristics and sensitivity. It has the advantage that it can be relatively easily produced on an electrophotographic photoreceptor having arbitrary electrophotographic properties such as durability.

Conventionally, a wide variety of carrier-generating substances or carrier-transferring substances have been proposed.

For example, a photosensitive layer consisting of a carrier generation layer made of amorphous selenium and a carrier transfer layer mainly composed of tribolytic N-vinylcarbazole is deposited on a photosensitive layer, which has been put to practical use.

However, a carrier generation layer made of amorphous selenium has a drawback of poor durability.

In addition, various electrophotographic photoreceptors using organic dyes or pigments as carrier-generating substances have been proposed.

For example, JP-A No. 47-37543 describes a 'Nobuko' photographic photoreceptor using 1 bisazo-f compound, JP-A No. 53-132347 using a trisazo compound, and JP-A No. 49-11136 using a phthalocyanine compound. has been done.

But these photoreceptors.

Characteristics such as sensitivity, residual potential, and stability when using one plant repeatedly are not necessarily satisfactory; A career move? In reality, the selection range of i-tora is limited, and as a result, there has not yet been a product that fully satisfies the broad demands of electrophotography.

In addition, in recent years, as the development of new sources has progressed,
There is an increasing need for photoreceptors that have high sensitivity to long wavelength sources of 660-700 nm obtained from D-type photoreceptors and the like.

(C) Object of the Invention An object of the present invention is to provide an electrophotographic photoreceptor containing an azo compound that is stable to heat and elements and has excellent carrier generation ability.

Another object of the present invention is to provide high sensitivity, low residual potential,
In addition, even after repeated use, these characteristics are K (no damage,
Our objective is to provide an electrophotographic photoreceptor with excellent durability.

Still another object of the present invention is to provide an electrophotographic photoreceptor containing an azo compound that can effectively act as a carrier generating substance even in combination with a wide variety of carrier transfer substances.

Yet another object of the present invention is to provide an electrophotographic photoreceptor that has sufficient practical sensitivity even to long wavelength light sources such as LEDs.

(B) Structure of the Invention The object of the present invention has been achieved by an electrophotographic photoreceptor characterized by having a photosensitive layer containing an azo compound represented by the following general formula (I).

(In the formula, R is an optionally substituted aryl group (inverted,
phenyl, p-bromophenyl, etc.), hu hydrogen atom, halogen atom (chlorine atom, bromine atom, etc.), alkyl group (eg methyl, ethyl, etc.).

or an alkoxy group (e.g. methoxy-ethoxy etc.)
B is a hydrogen atom, ) 10 Ken atoms (e.g., chlorine atom, bromine atom, etc.), an alkyl group (e.g., methyl).

ethyl, etc.), alkoxy groups (e.g. methoxy, ethoxy, etc.), acylamino groups (e.g. acetylamide 7 groups, etc.),
′! or hydroxyl group. n represents an integer from 1 to 4,
When n is other than 1, B1151. They may be the same or different. That is, in one aspect of the present invention, the azo compound represented by the general formula (1) is used as a photoconductive substance constituting the sensitive layer of a photosensitive material.

First, only the ability of the azo compound of the present invention to generate carriers is utilized, and the generation and transfer of carriers are performed using separate substances. By using it as a carrier-generating material in so-called function-separated electrophotographic photoreceptors, it has excellent film properties, excellent electrophotographic properties such as charge retention, sensitivity, and residual potential, and less fatigue deterioration even when used repeatedly. It is possible to produce an electrophotographic photoreceptor that exhibits stable characteristics without changing its characteristics even when exposed to heat or heat.

Specific examples of the azo compound useful in the present invention represented by the above general formula include those having the following structural formula, but the azo compounds of the present invention are not limited to this.

Exemplary Compounds These azo compounds can be easily synthesized by cyanizing a compound represented by the following general formula (n) by a conventional method, and then coupling it with a compound represented by the general formula Cm). At this time, an operation may be added to isolate the tetrazonium salt of the compound of general formula (■) in the form of a borofluoride salt or a zinc chloride salt.

(In the formula, A, B, n, and R are as described above.) Next, a method for synthesizing a representative example of the azo compound used in the present invention will be shown.

Synthesis example 1 (@water compound A7) 6-amino-2-(4-amino-3-methylphenyl)
Suspend 0.48t'g of benzoxazole in 6.5g of 2N salt solution and add 2frti of sodium nitrite to a water bath of 0°302g of sodium nitrite at 0°C. After 30 minutes, suspend in 42% HBF48-
was added, and the precipitated crystals were collected by filtration.

2-hydroxy-1LH-benzo(a)-carpan-3-carboxylic acid-2-ditylanilide 1.522N
, N-dimethylformamide solution @ (50-) was cooled to 0°C, the above crystals were added thereto, and then sodium acetate 0
．． An aqueous solution 4- of 66f was added dropwise over 10 minutes. 0℃
After stirring for 2 hours at room temperature and for 15 hours at room temperature, add 30
The product was collected by filtration and washed with methanol and acetone using a cyanothret extractor. Yield 1.87? . Melting point 300℃ or higher.

Other compounds of the present invention can also be synthesized according to the above synthesis examples.

The photoreceptor of the present invention is a photoreceptor containing 18A or 2a or more of an azo compound represented by the general formula (1).
It has I. Although various types of photosensitive layers are well known, the photosensitive layer of the photoreceptor for area photography according to the present invention may be in any of them. .

■ A photosensitive layer made of an azo compound ■ A photosensitive layer in which an azo compound is dispersed in a binder ■ A photosensitive layer in which an azo compound is dispersed in a well-known charge transfer substance A photosensitive layer in which a charge transfer/i1i containing a well-known charge transfer substance is laminated thereon.The azo compound represented by the above general formula generates charge carriers with extremely high efficiency when it absorbs a single element of gold. Although the generated carriers can be transferred using an azo-f-hyde compound as a medium, it is preferable to transfer them using a well-known charge transfer material as a medium. From this point of view, photosensitive layers having the forms (1) and (2) are particularly preferred.

Charge transfer materials are generally classified into two types: electron transfer materials and hole transfer materials, and both can be conveniently used in the photosensitive layer of the photoreceptor of the present invention.

It is also possible to use a mixture of the same type of shank, or a mixture of wafers with different shank functions. The electron transfer substance is an electron-withdrawing compound having an electron-withdrawing group such as a nitro group, a cyano group, or an ester group.
2.4.7-Dolinitrofluorenone, 2.4.5.7
- Nitrated fluorenone such as tetranitrophyllolenon, or compounds such as tetracyano, quinodimethane, tetracyanoethylene-2,4,5,7-titranitroxanthone, 2.4°8-trinidrothioxanthone, and electron-withdrawing Examples include polymerized compounds.

As a transport medium for the holes, for example, polymers having a heterocyclic compound in the side chain such as poly-N-vinylcarbazole, triazole derivatives, oxadiazo-
Examples include ethylene derivatives, pyrazoline conductors, triarylamine conductors, hydrazone spindles, and stilbene fatty conductors.

The charge transfer material is not limited to those described here, and for convenience, the carrier transfer material may be
Alternatively, two or more types can be used in combination.

The electrophotographic photoreceptor of the present invention can be manufactured according to a conventional method.

For example, an electrophotographic photoreceptor having a photosensitive layer of the type (2) above is prepared by applying a coating solution obtained by dissolving or dispersing the azo metal compound represented by the general formula (I) in an appropriate medium to a conductive support. It can be manufactured by coating and drying the photosensitive layer on top of the photosensitive layer and drying to form a photosensitive layer having a thickness of usually several μm to several tens of μm.

Butylamine is used as a medium for preparing the coating solution.

Basic solvents that dissolve azo compounds such as ethylenediamine, or ethers such as tetrahydrofuran and 1,4-dioxay; methyl ethyl ketone.

Ketones such as cyclohexanone; Aromatic hydrocarbons such as toluene and xylene; Aprotic polar bath media such as N,N-dimethylformamide, acetonitrile, N-methylpyrrolidone, and dimethyl sulfoxide; Alcohols; ethyl acetate, methyl acetate.

Examples include media for dispersing azo compounds such as esters such as methyl cellosolve acetate; chlorinated hydrocarbons such as dichloroethane and chloroform.

When used on a medium for dispersing azotized metals.

Azo compound 7 Particle size 5 μm or less - preferably 3 μm or less,
Optimally, it is necessary to make the particles finer to 1 μm or less.

Furthermore, as the conductive support on which the photosensitive layer is formed, any of those employed in well-known electrophotographic photoreceptors can be used.

Specifically, one example is a metal drum made of aluminum, copper, etc.
Examples include sheets, laminates and vapor deposits of these metal foils.

Additionally, metal powder, carbon black, and copper fluoride.

Examples include glass films, gelastic drums, paper, etc., which are conductive-treated by applying a conductive substance such as a polymer and a solute together with a suitable binder.・Further examples include plastic sheets and drums that contain conductive substances such as metal powder, carbon black, and carbon fibers and are made conductive.

If a binder is dissolved in the coating liquid used to form the photosensitive layer of the type (2) above, an electrophotographic photoreceptor having the photosensitive layer of the type (2) above can be produced.

In this case, the medium of the coating liquid is preferably one that dissolves the binder.

Styrene and vinyl acetate are used as binders.

Polymers and copolymers of vinyl compounds such as acrylic esters and methacrylic esters, phenoxy resin-polysulfone, arylate resin-polycarbonate, polyester, cellulose ester.

Examples include various polymers such as cellulose ether, urethane resin, Tomoe boxy resin, and acrylic polyol resin.

The amount of binder used is usually 0.1 to 1 azo compound.
This is the range of 5 double meals.

In addition, in forming this type of photosensitive N,
The bisazo compound in the binder is finely divided - e.g. particle size 3
It is preferable that the particles exist in the form of fine particles of 1 μm or less, particularly 1 μm or less.

Similarly, by dissolving a charge transfer medium in the coating liquid used to form the photosensitive layer of the type (1) above, an electrophotographic photoreceptor having the photosensitive layer of the type (2) can be produced. .

As the charge transfer medium, any of those exemplified above can be used.

Apart from charge transport media which can themselves be used as binders, such as polyvinylcarbazole and polyglycidylcarbazole, it is preferred to use other binders.

As the binder, any of those exemplified above can be used.

In this case, the amount of the binder used is usually 5 to 10 times the weight of the azo compound, and the amount of the charge transport medium used is usually 0.2 to 1.5 times the weight of the binder, preferably 0.3 times. The range is 1.2 times the weight. In the case of a charge transport medium which itself can be used as a binder, it is usually used in amounts of 5 to 10 times the weight of the azo compound.

In this type of photosensitive layer, as in the photosensitive layer of type (1) above, it is preferable that the bisazo compound be present in the charge transport medium and the binder in the form of fine particles.

If a coating solution obtained by mixing a charge transfer medium with a suitable medium is applied onto the g source layer of types (1) to (2) above, and is dried to form a charge transfer layer, a photosensitive layer of type (1) above will be obtained. Electrophotographic photoreceptors can be lined.

In this case, the photosensitive layers of types (1) to (4) above serve as a photosensitive layer. The charge transfer layer does not necessarily need to be provided on top of the charge generation layer, but may be provided between one charge generation layer and the conductive support. However, the former is preferable in terms of durability. The charge transfer layer is formed in the same manner as the photosensitive layer described in (2) above. That is, the above-mentioned feeling ``/l'' is obtained by removing the azo compound from the coating solution for forming the entire layer.
It may be used as a l-coating liquid. Usually the charge generation layer is 5
~50 μm thick. Of course, the photosensitive layer of the electrophotographic sensitive element of the present invention may contain a known sensitizer.

Suitable sensitizers include Lewis plates and dyes that form on charge transfer complexes with organic photoconductive materials.

Lewis acids - for example chloranil, 2,3-dichloro-1,4-naphthoquinone, 2-methylanthraquino/
-1-nitroanthraquinone, 1-chloro-5-nitroanthraquinone-2-chloranthraquinone, 7ena/
Quinones such as trenquinone, aldehyde Ys such as 4-nitrobenzaldehyde, 9-benzoylanthracene, indanedione, 3,5-dinitrobenzophenone-3,3'.

5. Ketones such as 5'-tetranitrobenzophenone.

Acid anhydrides such as phthalic anhydride and 4-chloronaphthalic anhydride; cyano compounds such as tetracyanoethylene, terephthalmalononitrile and 4-nitrobenzalmalonnitrile; and 3-benzalphthalide.

3-(α-cyano-p-nitrobenzal)phthalide, 3
-(α-cyano-p-nitrobenzal) phthalides and other electron-withdrawing 11 compounds are mentioned.

Examples of dyes include triphenylmethane dyes such as methyl violet, brilliant green, and crystal violet, thiazine dyes such as methylene blue, quinone dyes such as quinizarin, and cyanine dyes, pyrylium salts, thiapyrylium salts, and benzopyrylium salts.

In addition, there are other inorganic materials such as selenium and selenium-arsenic alloys24.
It may contain conductive particles, steel, organic conductive pigments such as phthalocyanine pigments, perylene pigments, etc.

Furthermore, the photosensitive layer of the electrophotographic sensitive element of the present invention may contain a well-known plasticizer in order to improve film formability, sinterability, and mechanical strength. As a plasticizer.

7 talic acid ester, shinshun ester, epoxy compound,
Chlorinated paraphyte/chlorinated fatty acid ester.

Examples include aromatic compounds such as methylnaphthalene.

Moreover, it goes without saying that a contact layer, an intermediate layer, and a transparent insulating layer may be included as necessary.

What) Examples Next, the present invention will be explained in detail using examples.
゛The present invention is not limited to the following examples as long as they do not go beyond the gist of the invention.

Example 1 0.2t of Exemplary Compound Boiled 7 and polyarylate (u-ioo manufactured by Unitika) o, z? and 1,2-dichloroethane2
The mixture was dispersed for 2 hours with Paint Conditioner in addition to 0-. The obtained dispersion at was coated on an aluminum plate and dried to form a carrier generation layer so that the film thickness after drying was 0.5 μm. Furthermore, 4-(N,N-dibenzylamino)-2-methylbenzaldehyde-diphenylhydrazone 122 and polyarylate (Unitika U-10
A bath solution prepared by dissolving 0) 12F in chlorobenzene 120F was coated and dried so that the film thickness after drying was 12 μm to form carrier transfer 11hN, and one electrophotographic photoreceptor of the present invention was tabulated. After storing the deuterium photoreceptors at a room temperature of 30° C. in a dark place, day and night, they were attached to an electrostatic paper tester JSP-428J (manufactured by Kawaguchi Oki Seisakusho), and the following characteristic tests were conducted.

That is, a voltage of 6 KV was applied to the charger to charge the photosensitive layer by corona discharge for 5 seconds, and then the photosensitive layer was left in the dark for 10 seconds, and the potential Vo (-V) at that time was determined.

Next, with the illuminance on the surface of one photosensitive layer being 30 lux, a halogen lamp was irradiated with the metal to form a photosensitive amount E2 (
lux・sec) was calculated. Furthermore, using the same light source, the amount of element required to lower one surface potential to -50V is E5g.
(lux・sec) was calculated. Similar measurements were repeated 100 times and the results are summarized in Table 1.

Table 1 Example 2-5 Exemplary compounds 1-4.1 as carrier generating substances, respectively
A total of 48 electrophotographic photoreceptors of the present invention were prepared in the same manner as in Example 1, except that 0.111 - was used.

Similar characteristic tests were conducted for each of them. The results are shown in Table 2.

Comparative Example 1-3 Three types of comparative photoreceptors were prepared using a trowel in the same manner as in Example 1, except that the following azo compound 1-3 was used as a carrier generating substance. (Comparative Compound 1) (Comparative Compound 2) (Comparative Compound 3) Example 6-7 For the sample prepared in Example 1-4, the light source was monochromatic light (wavelength 670 nm, light intensity 0.59 μW) from a halogen lamp.
Measurements were carried out in the same manner as in Example 1, except that the value was changed to /-). The results are shown in Table 4.

Table 4 Comparative Examples 4 and 5 The same measurements as in Examples 6-7 were performed on the samples prepared in Comparison Column 2.3. The results are shown in Table 5.

(G) Effects of the Invention The photoreceptor using the azo compound of the present invention has high sensitivity, and when it is used repeatedly, the sensitivity and chargeability change.

It has little optical fatigue and is extremely durable.

Furthermore, it has sufficient practical sensitivity to a light source of 670 nm, and can be widely used in photoreceptors of printers that use a single-source diode as a light source.

Claims (1)

[Scope of Claims] An electrophotographic photoreceptor characterized by having a photosensitive layer containing an azo compound represented by general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R is an optionally substituted aryl group, A is a hydrogen atom, a halogen atom, an alkyl group, or an alkoxy group, B is a hydrogen atom, a halogen atom, Represents an alkyl group, alkoxy group, acylamino group, or hydroxyl group. n is 1
represents an integer of ~4, and when n is other than 1, B may be the same or different. )