JPH0272372A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain the photosensitive body which is excellent in electrophotographic characteristics such as charge holding power and sensitivity and has less fatigue deterioration after repetitive use by providing a photosensitive layer contg. a specific azo compd. on a conductive base. CONSTITUTION:The azo compd. expressed by formula I is used as the photoconductive material constituted as the photosensitive layer of the photosensitive body. In formula I, Pz is expressed by formula II or formula III; Y1, Y2 respectively denote a hydrogen atom, halogen atom, alkyl group, alkoxy group or hydroxy group; Cp denotes a residual coupler group. The photosensitive body which has excellent carrier generating power, has high sensitivity and small residual potential, not changed in these characteristics even after the repetitive use and has the excellent durability is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor having a photosensitive layer containing a specific azo compound.

[Conventional technology]

Conventionally, as electrophotographic photoreceptors, inorganic photoreceptors having a photosensitive layer containing an inorganic photoconductive compound such as selenium, zinc oxide, cadmium sulfide, ornicon as a main component have been widely used. However, these are not necessarily satisfactory in terms of sensitivity, thermal stability, moisture resistance, durability in repeated use, etc. For example, when selenium crystallizes, its properties as a photoreceptor deteriorate, which is difficult to manufacture.Also, selenium crystallizes due to heat, fingerprints, etc., and its performance as a photoreceptor deteriorates. Cadmium sulfide also has moisture resistance, durability,
Even zinc oxide has durability issues.

In order to overcome these drawbacks of inorganic photoreceptors, research and development have been actively conducted in recent years on organic photoreceptors having photosensitive layers containing various organic photoconductive compounds as main components. For example, Japanese Patent Publication No. 50-10496 describes an organic photoreceptor having a photosensitive layer containing poly-N-vinyl rubazole and 2,4,7-1-dinitro-9-fluorenone. However, this photoreceptor is not necessarily satisfactory in sensitivity and durability.

In order to improve these drawbacks, attempts have been made to develop organic photoreceptors with higher performance by assigning the carrier generation function and the carrier transport function to different substances. Many studies have been conducted on such so-called function-separated type photoreceptors because each material can be selected from a wide range and a photoreceptor having arbitrary performance can be produced relatively easily.

[Problem that the invention seeks to solve]

A large number of compounds have been proposed as carrier-generating substances in the functionally separated photoreceptor described above.

An example of using an inorganic compound as a carrier generating substance is amorphous selenium described in Japanese Patent Publication No. 43-16198, which is used in combination with an organic photoconductive compound. The drawback that the generation layer crystallizes due to heat and deteriorates the characteristics as a photoreceptor has not been improved.

Furthermore, many electrophotographic photoreceptors using organic dyes or organic pigments as carrier-generating substances have been proposed.

For example, as an electronic photoreceptor containing a bisazo compound in the photosensitive layer,
No. 57, No. 55-117151, No. 56-46237
No. etc. are already publicly known.

However, these bisazo compounds do not necessarily satisfy the characteristics of sensitivity, residual potential, or stability during repeated use, and the range of selection of carrier transport materials is also limited, which makes them difficult to meet the wide demands of electrophotographic processes. It does not fully satisfy.

[Purpose of the invention]

The purpose of the present invention is to provide an electrophotographic photoreceptor (hereinafter abbreviated as photoreceptor) containing a specific azo compound with excellent carrier generation ability.
Our goal is to provide the following.

Another object of the present invention is to provide a photoreceptor with high sensitivity, low residual potential, and excellent durability whose characteristics do not change even after repeated use.

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

[Means for solving problems]

As a result of intensive research to achieve the above object, the present inventors discovered that the azo compound represented by the following maximum (1) can function as an active ingredient of a photoreceptor, and constructed the present invention.

General CI) Y and Y2 each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a hydroxy group. cp represents a coupler residue, and preferred examples include the following.

Y+ Y2 Here, Q ', Q '', Q ', Q ', Q
' and Q'' (represents ma).

Also, RI O, RI l, Rl 2 , R+ 3
, R mouth a+6. R mouth, R17R18 and Rlg are
hydrogen atom, alkyl group (preferably 1 to 8 carbon atoms),
Alkoxy group (preferably 1 to 8 carbon atoms), halogen atom, cyano group, ester group (e.g. acetoxy group, propionyloxy group, etc.), acyl group (e.g. acetyl group,
benzoyl group, etc.), dialkylamino group, dialkylamine group, diarylamino group, hydroxy group, or nitro group. However, no represents an integer from 1 to 4, and no
When is 2 or more, each R10 may be a different substituent. Moreover, 111 + n 4 and R7 are 1 to 5
, and when n l + n 4 and R7 are 2 or more, R's 414 and R'' may each be different substituents.Furthermore, n2rQ3+n5*Q6+QB and n.

represents an integer from 1 to 7, R2+13+n%
+ 116 + na and n.

is 2 or more, R", R", R", R", R" and R
19 may be different substituents.

Also, two RIJ+2. RIJIJISR+6
．． R1, RIM, and R15 may form an aliphatic carbocycle or an aliphatic heterocycle.

R2J 22 and R23 represent a hydrogen atom, an alkyl group (preferably having 1 to 8 carbon atoms), or an aryl group (for example, a phenyl group).

Alkyl group (preferably 1 to 8 carbon atoms), alkoxy group (preferably 1 to 8 carbon atoms), /10 gen atoms, cyano group, ester group (e.g. acetoquine group, propionyloxy group, etc.), anlu group (e.g. acetyl group, benzoyl group, etc.), dialkylamino group, dialkylamino group, diarylamino group, or hydroxyl group. However, nll represents an integer of 1 to 5, and when nil is 2 or more, R3+ may be a different substituent.

R1 represents a hydrogen atom, an alkyl group, an amine group, a dialkylamino group, a diarylamino group, a dialkylamino group, a carbamoyl group, a carboxyl group and its ester group, or a cyan group.

R2 and R3 represent an alkyl group, an aralkyl group, a kyl group, an alkoxy group, a halogen atom, a cyano group, an ester group, an acyl group, a dialkylamino group, a dialkylamino group, a diarylamino group, or a hydroxy group. However, nz+ represents an integer of 1 to 5, and when nz+ is 2 or more, R'' may be a different substituent.

Particularly preferred are those in which y l and y 2 are hydrogen atoms, methyl groups, or methoxy groups.

[Effects of the present invention]

Details will be described in Examples below, but the photoconductive material constituting the photosensitive layer of the photoreceptor of the present invention is
By using the azo compound represented by [I], it is possible to provide a photoreceptor that is excellent in electrophotographic properties such as charge retention and sensitivity, and exhibits less fatigue deterioration when used repeatedly.

Specific examples of the azo compounds useful in the present invention are shown below, but the azo compounds of the present invention are not limited thereto.

Exemplary Compound (1) Among the compounds represented by the general formula (1), those having the structure of -maximum (II) General formula (II) Exemplary Compound (2) Among the compounds represented by the general formula, those having the structure of -maximum (II) General formula (III) ).

general formula ([[) Exemplary compound (3) general formula Among the compounds represented by - maximum (IV) has the structure of general formula Exemplary compound (4) general formula - Maximum (V) in the compound represented by Something with the structure of

General formula [■] Exemplary compound (5) maximum Among the compounds represented by - maximum (Ml) of 1. Those who make M construction general formula Exemplary compound (6) general formula Among the compounds represented by - maximum [■] What does the structure of.

general formula Exemplary compound (7) general formula Among the compounds represented by - maximum [■] of something with a structure maximum Indicated compound (8) In the compound represented by general formula (1) Something with the structure of

General formula [■] Maximum A -330 A -331 A -338 t to -336 The bisazo compound represented by the general formula [I] of the present invention can be easily synthesized by a known method.

Synthesis Example 1 (Synthesis of Exemplary Compound No. A 42) J,
L, Leiserson; A, Weisberger
, Org 5ynth, C.

11, Vol IV, 183 (1955), 4-chloroacetylanilide was synthesized, and from this, a pyrazine compound was synthesized as described below with reference to JP-A-62-270623. 160g p-
Chloracetylacetanilide was dissolved in 1.5Q dimethylacetamide and cooled to 0°C.

The above solution was saturated with dry ammonia, heated to room temperature for 2 hours, then heated to 60°C to 70°C for 2 hours, and further heated to reflux conditions for 12 hours. 3 while the reaction solution is hot.
00 mQ of water was added and cooled to room temperature, and the formed crystals were filtered off. Yield was 350g. This crystal is 2.5-
It is bis(4-acetamidophenyl)pyrazine. When 1.212 g of water was further added to the filtrate of the reaction solution, further crystals were precipitated. This was recrystallized from a mixed solvent of DMAC/water (2/1) to obtain 27.6 g of crystals. This is 2.6-bis(
4-acetamidophenyl) pyrazine.

10.38 g (0.03 mol) of the 2,6-bis(4-acetamidophenyl)pyrazine obtained here was added with 1 mol of concentrated hydrochloric acid.
The mixture was dispersed in 20 m4 and heated under reflux for 4 hours. After cooling, the precipitated solid was filtered out and dispersed in 200 m12 of water. The mixture was made strongly alkaline by adding solid caustic soda and the product was filtered off.

The product was recrystallized from DMAC/water. Yield is 7.56
It is g. The product is 2,5-bis(4-aminophenyl)pyrazine.

A carrier-generating substance was synthesized from the diamino compound thus obtained by the following method.

Synthesis Example 1-1 (Synthesis of Exemplified Compound A-42) 2.5-bis(4-aminophenyl)pyrazine 5.24g (0,0
2 mol) in 20 ml of hydrochloric acid. Dispersed in 40mQ of water, 5°
1.4 g of sodium nitrite (0,0
A solution of 2 mol) dissolved in 5+J of water was added dropwise. After stirring for another hour at the same temperature, insoluble matter was removed by filtration, and 4.6 g of ammonium hexafluorophosphate was added to the filtrate with 50 n of water.
A solution dissolved in Q was added. The precipitated tetrazonium salt was collected by filtration and treated with N,N-dimethylformamide (DMF)]
Dissolved in 000m. 5.26 g of 2-hydroxy-3-naphthoic acid anilide (0,
A solution of 02 mol) dissolved in 200 m+1 of DMF was added dropwise.

While continuing to maintain the temperature below 5°C, add 6 g (0.04 mol) of triethanolamine to 30 mQ of DMF.
was added dropwise, and the mixture was stirred at 5°C or lower for 1 hour and at room temperature for 4 hours. After the reaction, the precipitated crystals were collected by filtration, washed with DMF, washed with water, and dried to obtain 5.21 g of the desired product.

Synthesis Example 1-2 (Synthesis of Exemplified Compound A-22) 5.24 g (0,0
2 mol) in 20 mQ of hydrochloric acid and 40 m12 of water,
While keeping the temperature below °C, 1.4 g of sodium nitrite (0,
02 moles) in 5 m of water! 2 was added dropwise. After stirring for another hour at the same temperature, insoluble matter was removed by filtration, and 4.6 g of ammonium hexafluorophosphate was added to the filtrate in 50 g of water.
A solution of n++2 was added. The precipitated tetrazonium salt was collected by filtration and treated with N,N-dimethylformamide (DM
F) Dissolved in 100 mc. While keeping the temperature below 5℃,
-Hydroxy/-3(4-methoxy-2-methylphenylcarbamoyl)-benzo[a]carbazole 7.80
A solution of g (0.02 mol) dissolved in 200 mQ of DMF was added dropwise.

Continue to maintain the temperature at 5°C, then add triethanolamine 6.
g (0.04 mol) dissolved in 30 mQ of DMF was added dropwise, and the mixture was stirred at below 5°C for 1 hour and at room temperature for 4 hours. After the reaction, the precipitated crystals were collected by filtration, washed with DMF, washed gently and dried to obtain 6.46 g of the desired product.

The azo compound of the present invention has excellent light guiding TjL properties,
When producing a photoreceptor using this, it can be produced by providing a photosensitive layer in which the azo compound of the present invention is dispersed in a binder on a conductive support. Particularly when a so-called functionally separated photoreceptor is constructed by using a carrier-generating substance that utilizes particularly excellent carrier-generating ability among photoconductivity, and using it together with a carrier-transporting substance that can effectively act in combination with the carrier-generating substance. Excellent results.

The function-separated photoreceptor may be a dispersed type photoreceptor, but it is more preferably a laminated flood photoreceptor in which a carrier generation layer containing a carrier generation substance and a carrier transport layer containing a carrier transport substance are laminated.

When the azo compound of the present invention is used as a carrier-generating substance, examples of the carrier-transporting substance used in combination with the azo compound include electron-accepting substances that easily transport electrons such as trinitrofluorenone or tetranitrofluorenone, as well as poly-N - Polymers having heterocyclic compounds in their side chains such as vinylcarbazole, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, polyarylalkane derivatives, phenylenediamine derivatives, hydrazone derivatives, amino-substituted chalcone derivatives , triarylamine derivatives, carbazole derivatives, stilbene derivatives, phenothiazine derivatives, and other electron-donating substances that easily transport holes, but the carrier transporting substance used in the present invention is not limited to these.

Various types of mechanical configurations of photoreceptors are known, and the photoreceptor of the present invention can take any of these forms.

Usually, the configuration is as shown in FIGS. 1 to 6.

In FIGS. 1 and 2, a photosensitive layer 4 consisting of a laminate with a carrier transport layer 3 containing the above-mentioned azo compound as a main component is provided on a conductive support l.

As shown in FIGS. 3 and 4, this photosensitive layer 4 may be provided via an intermediate layer 5 provided on a conductive support. When the photosensitive layer 4 has a two-layer structure in this manner, a photoreceptor having the most excellent electrophotographic properties can be obtained.

Further, in the present invention, as shown in FIGS. 5 and 6, a photosensitive layer 4 comprising a carrier-generating substance 7 dispersed in a layer 6 containing a carrier-transporting substance as a main component is attached to a conductive support l.
It may be provided directly thereon or via the intermediate layer 5.

The carrier generation layer 2 constituting the two-layered photosensitive layer 4 is applied directly onto the conductive support 11 or the carrier transport layer 3, or after providing an intermediate layer such as an adhesive layer or a barrier layer as required, for example, as follows. It can be formed by the following method.

M-1) A method of applying a solution in which an azo compound is dissolved in a suitable solvent, or a solution in which a binder is added and mixed as necessary.

M-2) A method in which an azo compound is made into fine particles in a dispersion solvent using a ball mill, a homomixer, etc., and a binder is added if necessary to mix and disperse the resulting dispersion.

Examples of the solvent or dispersion medium used for forming the carrier generation layer include butylamine, diethylamine, ethylenediamine, isopropanolamine, triethanolamine,
triethylenediamine, NN-dimethylformamide,
Acetone methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, l,2-dichloroethane, 112-1-lichloroethane, 1,1,
i Trichloroethane, tetrachloroethane, dichloromethane, tetrahydrofuran, dioxane, methanol, ethanol, impropatol, ethyl acetate, butyl acetate, dimethylformhokind, and the like.

When using a binder in the carrier generation layer or carrier transport layer, any binder can be used, or it can be hydrophobic and
It is preferable to use a film-forming polymer that has a high dielectric constant and is electrically insulating.

Examples of such high molecular weight polymers include, but are not limited to, the following.

P-1) Polycarbonate P-2) Polyester P-3) Methacrylic resin P-4) Acrylic resin P-5) Polyvinyl chloride P-6) Polyvinylidene chloride P-7) Polystyrene P-8) Polyvinyl acetate P-9 ) Styrene-butadiene copolymer P-10)
Vinylidene chloride-acrylonitrile copolymer p-11) Vinyl chloride-vinyl acetate copolymer P-1
2) Vinyl chloride-hinyl acetate-maleic anhydride copolymer P-13) Silicone resin P-14) Silicone-alkyd resin P-15)
Phenol formaldehyde resin, p-16)
Styrene-alkyd resin P-17) Poly-N-vinylcarbazole P-18) Polyvinyl butyral P-19) Polyhydrinylfomar These binders can be used alone or in a mixture of two or more.

The thickness of the carrier generation layer 2 formed in this way is
It is preferably 0.01 to 20 μm, more preferably 0.05 to 5 μm. Further, when the carrier generation layer or the photosensitive layer is a dispersion type, the particle size of the azo compound is preferably 5 μm or less, more preferably 1 μm or less.

The conductive support used in the photoreceptor of the present invention is a metal plate including an alloy, a metal drum or a conductive polymer, a conductive compound such as indium oxide, or a metal thin film such as aluminum, palladium, or gold including an alloy. Examples include paper, plastic film, etc. that have been made conductive by coating, vapor depositing, or laminating layers.

As an intermediate layer such as an adhesive layer or a barrier layer, in addition to the polymer used as the binder, organic polymer substances such as polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, or aluminum oxide are used.

The photoreceptor of the present invention has the above-mentioned structure, and as is clear from the examples described later, it has excellent charging characteristics, sensitivity characteristics, and image forming characteristics, and is particularly resistant to fatigue deterioration even after repeated use. It has excellent durability.

〔Example〕

The present invention will be specifically explained below using Examples, but the embodiments of the present invention are not limited thereto.

Example l Vinyl chloride-vinyl acetate-
Maleic anhydride copolymer [S-LEC MF-10
An intermediate layer with a thickness of 0.05 μm made of J (manufactured by Tsukisui Kagaku Co., Ltd.) was provided, and 2 g of exemplified compound A-2 and 2 g of polycarbonate resin "Panlite L-1250J (manufactured by Ondai Kasei Co., Ltd.) were placed thereon. was added to 1,2-dichloroethane llomQ and dispersed in a ball mill for 12 hours. This dispersion was applied to a dry film thickness of 0.5 μm to form a carrier generation layer, and a carrier transport substance was added on top of this. As, 6g of the following structural formula (Kl) was added to a polycarbonate rod (Moonji [
Panlite L-1250J log is 1.2-; The film thickness after drying the liquid dissolved in chloroethane 80mQ is 15μ
A carrier transport layer was formed by coating the photoreceptor to form a photoreceptor of the present invention.

The required exposure amount (half-reduced exposure amount) E% was determined.

In addition, the surface potential (residual potential) VR after exposure with an exposure amount of 30 (2ux-sec) was determined.
I did it several times. The results are shown in Table 1.

Comparative Example l The following bisazo compound (G-1) was used as a carrier generating substance.
A comparative photoreceptor was prepared in the same manner as in Example 1, except that .

(G-1) The photoreceptor submerged as described above was subjected to the following characteristic evaluation using an electrostatic paper tester model EP A-8100 manufactured by Kawaguchi Electric Seisakusho Co., Ltd. After being charged for 5 seconds at a charging voltage of -5KV, it was left in the dark for 5 seconds, and then the illuminance on the photoconductor surface was reduced to 3KV.
Irradiate with halogen lamp light so that it becomes 512ux,
To attenuate the surface potential by half, measurements were carried out on this comparative photoreceptor in the same manner as in Example 1, and the results were as shown in Table 1.
The results shown are obtained.

As is clear from the above results, the photoreceptor of the present invention is extremely superior in sensitivity, residual potential, and repetition stability compared to the comparative photoreceptor.

Examples 2 to 9 Photoreceptors of the present invention were prepared in the same manner as in Example 1, except that the exemplified compounds shown in Table 2 were used as carrier-generating substances, and the same measurements were performed. We obtained the results shown below.

Table 2 Examples 1O to 12 Exemplary compounds A-2A6 and A-1 as carrier-generating substances
A photoreceptor of the present invention was prepared in the same manner as in Example 1, except that the following compounds were used as carrier transport substances, respectively, and the same measurements were performed. The results shown in Table 3 were obtained. .

(K-2) (K-3) (K-4) C,H.

Table 3 A photoreceptor of the present invention was produced.

(K-5) Example 13 Aluminum was vapor-deposited on a polyester film, the intermediate layer used in Example 1 was provided, and exemplified compound N
2 g of A-9 and 2 g of polycarbonate (panlite L-1250) were added to 1,2-dichloroethane 110++1 and dispersed for 8 hours using a sand grinder. This dispersion was dried until the film thickness was 0. 5 μm to form a carrier generation layer.Furthermore, on top of that, 6 g of the following structural formula (K-5) was applied as a carrier transport substance to a polycarbonate resin [Panlite L~1300] (manufactured by Ondai Kasei Co., Ltd.). )log and 1,2-dichloroethane 80m
A carrier transport layer was formed by applying a solution dissolved in Q to a film thickness of 15 μm after drying, and the same measurements as in Example 1 were performed on this photoreceptor, with the results shown in Table 4. Ta.

Comparative Example 2 An electrophotographic photoreceptor was produced in the same manner as in Example 13, except that a stilbene azo pigment represented by the following structural formula (G-2) was used as a carrier-generating substance.

The same measurements as in Example 1 were performed on this comparative photoreceptor, and the results shown in Table 4 were obtained.

(G-2) Table 4 50g was dissolved in 400mQ of 1,2-dichloroethane and coated to form a carrier transport layer such that the film thickness after drying was 18 μm, and a drum-shaped photoreceptor was prepared.

(K-6) As is clear from the above results, the photoreceptor of the present invention is extremely superior in sensitivity, residual potential, and repetition stability compared to the comparative photoreceptor.

Example 14 A 0.05-μ thick layer made of hinyl chloride-vinyl acetate-maleic anhydride copolymer "Eslenc MF-104 (manufactured by Tanezu Kagaku Co., Ltd.)" was coated on the surface of an aluminum drum with a diameter of 160 mm.
m intermediate layer is provided, and 2 g of Exemplified Compound A-46 is provided thereon.
and 2 g of polyester resin [Panlite L-200J (manufactured by Toyobo Co., Ltd.) and 110 m of 1,2-dichloroethane (
1 and dispersed for 24 hours using a ball mill dispersion machine, the dispersion was applied to a dry film thickness of 0.6 μm to form a carrier generation layer.

Furthermore, 30 g of the following compound (K9) and polycarbonate resin rZ-200J (manufactured by Mitsubishi Gas Chemical Co., Ltd.) were added to the photoreceptor thus prepared in an electrophotographic copying machine r.
When the image was copied by installing it on a modified U-Bix1500M RJ (manufactured by Konica Corporation), a copy image with high contrast, faithful to the original image, and clear was obtained.

Moreover, this did not change even after repeating 10,000 times.

[Brief explanation of the drawing]

1 to 6 are sectional views showing examples of the mechanical structure of the photoreceptor of the present invention, and 1 to 7 in the figures indicate the following, respectively. 1... Conductive support 2... Carrier generating layer 3... Carrier transporting layer 4... Photosensitive layer 5... Intermediate layer 6... Layer containing carrier transporting substance 7... Carrier generating substance

Claims (3)

[Claims] (1) An electrophotographic photoreceptor comprising a photosensitive layer containing an azo compound represented by the following general formula [I] on a conductive support. General formula [I] ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [In the formula, Pz represents ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼. Y_1 and Y_2 each represent a hydrogen atom, an alkyl group, an alkoxy group, or a hydroxy group. Cp represents a coupler residue. ] (2) The photosensitive layer contains a carrier transporting substance and a carrier generating substance, and the carrier generating substance has the general formula [I
The electrophotographic photoreceptor according to claim 1, which is an azo compound represented by the following. (3) The electrophotographic photoreceptor according to claim 1 or 2, wherein the photosensitive layer has a laminated structure of a carrier generation layer containing a carrier generation substance and a carrier transport layer containing a carrier transport substance.