JPS62272266A - Electrophotographic sensitive body and its preparation - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body improved in sensitivity, response speed, and the like by laminating an electrostatic charge generating layer and a charge transfer layer on a conductive substrate to form the electrophotographic sensitive body, and adding a specified compound as a degradation preventive to the charge transfer layer. CONSTITUTION:In the functionally separated type electrophotographic sensitive body provided with the charge generating layer and the charge transfer layer on the conductive substrate, the charge transfer layer contains as the degradation preventive, one of the dihydroxynaphthalenes or their derivatives represented by formula I in which each of R1-R8 is H, halogen, hydroxy, amino, alkylated or acylated amino, lower alkyl, aryl, acyloxy, or alkoxy, and any 2 of R1-R8 need to be hydroxy. This preventive is added in an amount of >=0.0001wt%, preferably, 0.1-0.001wt% of the total weight of the charge transfer material, a binder polymer, and a solvent.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an electrophotographic photoreceptor, particularly a mechanically separated electrophotographic photoreceptor with excellent characteristics such as sensitivity and response speed. The present invention relates to a manufacturing method thereof.

(Prior art) An electrophotographic photoreceptor is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-148255.
It is well known and has been described in numerous documents as disclosed in the above publication. This publication describes and describes the general structure of an organic electrophotographic photoreceptor, including (a) a photoconductor having a photoconductive layer comprising a charge-generating substance and a charge-transporting medium on a conductive support; (b) A photoconductive layer consisting of two layers, in which a charge transport layer is provided on a conductive support and a charge generation layer is laminated on this layer, (c) or vice versa. It has been disclosed that a light guiding layer '1i is provided with a two-layered light guide layer with a charge transport layer laminated thereon.

On the other hand, "Photographic Science and Engineering/;f (Ph
otog-raphic 5science and E
ngineering) j 27(1), 14-19
(1983) describes that a recent trend is to use a two-layer laminate structure in which charge generation and charge transport 11.1F are carried out in two layers laminated to a conductive support 1. Generally, electrophotographic photoreceptors have separate materials for charge generation and charge transport, and of these materials, the charge transport part is composed of a charge transport material and a binder polymer. What is the response speed of the photoreceptor? In order to achieve this, it is necessary to use a material with fast carrier mobility and to increase the ratio of charge transporting material to the binder polymer.This document also shows that by doing this, the residual potential becomes smaller and a larger contrast potential can be obtained. It has been clarified in

On the other hand, in the above-mentioned Japanese Patent Application Laid-Open No. 57-148255, in the description of a photoreceptor having a two-layer structure in which charge generation and charge transport are divided into separate layers, a charge transport material is added to an inert resin binder. It is described that a charge transport layer is prepared by applying a uniform solution dissolved in a solution onto a support or a charge generation layer and drying it. As binder polymers for the charge transport layer, polystyrene, polyvinyl chloride, polyvinyl acetate,
Examples include vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, alkyd resin, acrylic resin, polyacrylonitrile, polycarbonate, polyamide, polyketone, polyacrylamide, butyral resin, ester, polyurethane, polyurethane, and phenol resin.

Examples of organic solvents that can be dissolved to coat these binder polymers and charge transport materials include benzene, toluene, xylene, chlorobenzene, acetone, methyl ethyl ketone, cyclohexanone, methanol, ethanol,
Isopropanol, ethyl acetate, methyl cellosolve, carbon tetrachloride, chloroform, dichloromethane, tetrahydrofuran, dioxane, dimethylformamide, and dimethyl sulfoxide are listed.

(Problem that the invention attempts to solve) However, many charge transport materials are unstable.

In particular, when it is dissolved in a solvent, it often deteriorates during storage, resulting in deterioration of the response characteristics, decrease in sensitivity, and increase in residual potential of photoreceptors that are coated afterward. This was particularly likely to occur when the binder polymer contained a catalyst used during polymer synthesis or when the solvent was a chlorine-based solvent. This deterioration often appears as a brown coloration of the coating solution, which is a problem. Therefore, in the present invention, by preventing the deterioration of a coating solution in which a charge transport material is dissolved in a solvent together with a binder polymer, and by using this coating solution, an electrophotographic photoreceptor with improved characteristics such as sensitivity and response speed can be produced. The purpose is to provide a method for producing the same.

(Means for Solving the Problems) The present invention adds a specific deterioration inhibitor to a coating solution in which a charge transport material and a binder polymer are dissolved in an organic solvent,
The present invention is based on the finding that the L diode can be achieved by forming a charge transporting portion using this coating solution.

Therefore, the present invention provides a conductive support l2't/751! ,
In a photoreceptor of type O-type, in which the charge transporting part and the 7L load transporting part are made of separate materials, the charge transporting part has the following general formula.

(R+, R2, R3, Ra, R5, Rh, R in the formula
Two or more r and R8 are the same or different, and are a hydrogen atom t and a halogen atom F.

hydroxyl group, amine group substituted with an alkyl group such as amine group, lower alkyl group such as amino group substituted with an alkyl group such as aryl group, 7 siloxy group such as -0COCH3, -0C
H3, indicates a flukoxy group such as -0C2H5, and R
The present invention relates to an electrophotographic photoreceptor characterized in that dihydroxynaphthalene or a derivative thereof represented by (any two of 1-R8 always represent a hydroxyl group) is added as a deterioration inhibitor.

The electrophotographic photoreceptor of the present invention has excellent characteristics such as fast response speed, low residual potential, and high sensitivity because the dihydroxynaphthalene of formula (1) or its derivative is contained in the charge transport material as a deterioration inhibitor. It is something.

The present invention also relates to a method for manufacturing the above electrophotographic photoreceptor, and this method involves forming a conductive support in which a portion that generates a charge and a portion that transports a charge are formed using separate materials. In manufacturing a separate type electrophotographic photoreceptor,
A charge transport layer is formed by adding dihydroxynaphthalene of the above formula (1) or a derivative thereof as a deterioration inhibitor to a solution in which a charge transport material and a binder polymer are dissolved in an organic solvent, and using the mixture as a coating liquid, and depositing the charge transport layer on a conductive support or It is characterized in that it is formed by coating and detonating the charge generation layer E of the conductive support.

The charge transporting material, binder polymer, and organic solvent for forming the coating solution used in the method of the present invention may be those conventionally used. 0.0001% or more based on the total weight of the material, binder polymer and solvent, preferably 0
．． Add 1 to o, oot%. Anti-deterioration agent is 0.000
If the amount is less than 1% by weight, the effect of adding it will not be obtained. On the other hand, the northern limit is determined by the solubility in the solvent used, and it is usually not necessary to add more than 1% by weight. In addition, in the method of the present invention, in order to improve the response characteristics of the photoreceptor, the mixing ratio of the binder polymer and the charge transport material is 4:1-1 by weight.
It is preferable to set it as the range of :l.

Generally, when additives are added to the coating solution used to form the charge transport layer, the characteristics of the photoreceptor produced often deteriorate; however, the inhibitor in the present invention can be added without causing such adverse effects. As a result, the characteristics of the photoreceptor are dramatically improved.

(Function) According to the present invention, since a deterioration inhibitor is added to the coating solution, this solution does not deteriorate during storage.

(Examples) Examples of the electrophotographic photoreceptor of the present invention and its manufacturing method will be described below. However, although the embodiments of the present invention described below are explained using preferred specified materials, numerical conditions, and arrangement relationships within the scope of the present invention, these are merely illustrative, and the present invention does not apply to these materials. ,
It is clear that the present invention is not limited only to numerical conditions and arrangement relationships.

χ & 4 ↓ A 0.2 μm vapor-deposited film of indium phthalocyanine (Japanese Unexamined Patent Publication No. 59-44054) was formed on an aluminum base material to form a charge generation layer.

A charge generation layer of 15 Bm was formed on this charge generation layer by a dip coating method using coating solutions 1 to 13 for forming a charge transport layer having the following composition to obtain electrophotographic photoreceptors 1 to 13 of Examples. Ta.

The cross-sectional structure of these photoreceptors is shown in Figure 1.
12 is an indium phthalocyanine vapor deposited layer, thickness 0.2 JLm, 13 is a charge transport layer, thickness 1
It is 5m.

Coating solution Composition Coating solution 1 (a) Binder polymer: Polyester resin (Vylon 2
0G Toyobo Co., Ltd., trade name) ft00g (b) Charge transport material: 1,2,3,4-tetrahydroquinoline-6-carboxyaldehyde hydrazone derivative (Japanese Patent Application Laid-open No. 148248/1980) (Betsu IN (manufactured by Minami Kogyo Sangyo Co., Ltd.) 00g (c) MW: Chloroform (contains 0.5% ethyl alcohol to prevent decomposition) (special grade, manufactured by Kanto Kagaku Co., Ltd.) 2000ml (d) Anti-deterioration agent: 1,5 -Dihydroxynaphthalene (Tokyo Kasei (
Co., Ltd.) H Coating Solution 2 (A) Heiron 200 ft
00 g (b) Hydrazone of formula (2) 3
00 g (c) Dioxane 250
0m sentence cyclohexanone 5QOmJL
(d) 1.5-dihydroxynaphthalene 0.3g
Coating solution 3 (a) Binder polymer, polycarbonate (Lexan 1
41, manufactured by Engineering Plastics Co., Ltd., trade name) 400 g (B) Hydrazone of formula (2) 400 g (C) Chloroform
2000m viewing (d) 1.5-dihydroxynaphthalene 0.3g coating solution 4 (a) Byron 200 800
g(b) Hydrazone of formula (2) 200
g(c) Toluene, ELS (manufactured by Kanto Chemical Co., Ltd.) 90
0m methyl ethyl ketone, ELS (manufactured by Kanto Kagaku Co., Ltd.)
300mJ1 Butyl acetate, E
LS (manufactured by Kanto Kagaku Co., Ltd.) 600m cyclohexanone, special grade (manufactured by Kanto Kagaku Co., Ltd.)
300mJl (d) 1.5-
Dihydroxynaphthalene 7 0.3 g Coating solution 5 (a) Byron 200 [O
g (b) Charge transport material: p-diethylaminobenzaldehyde diphenylhydrazone (Seinan Kogyo Sangyo (c) Toluene 900m ethyl ethyl ketone 300m butyl acetate
8OQm Cyclohexanone
300m sentence (d) 1.5-dihydroxynaphthalene 0.3g coating solution 6 (a) Byron 200 800
g (b) Hydrazo 7 of formula (2) 300g
(c) Dichloromethane 2000m (d) 1.5-dihydroxynaphthalene 0.3g
Coating solution 7 (a) Byron 200 800
g (b) Charge transport material = 1-phenyl-3(p-diethylaminostyryl)-5-(p-diethylaminophenyl)-2-biranrin (manufactured by Seinan Koyo Sangyo Co., Ltd.) 300 g (c) Chloroform 2000 m
d) 1.5-dihydroxynaphthalene 0.3g coating solution 8 (a) Byron 200 Bo
o g (b) Hydrazo 7 of formula (2) 300
g(c) Chloroform 2000m
Sentence (d) 1,? -Dihydroxynaphthalene (manufactured by Tokyo Kasei Co., Ltd.) 0.3 g H Coating solution 9 (a) Byron 200 Bo
o g (b) Hydrazo 7 of formula (2) 300g
(c) Chloroform 200Qm sentence (
d) 2,3-dihydroxynaphthalene (Tokyo Kasei Co., Ltd.)
) 0.3g Coating solution 10 (a) Byron 200 600
g (b) Hydrazone of formula (2) 300
g (c) Chloroform 2000 m (d) 1,4-dihydroxynaphthalene (manufactured by Tokyo Kasei Co., Ltd.) 0.3 g nt-+ (i) Byron 200 800
g (b) Hydrazo 7 of formula (2) 300g
(c) Chloroform 2000 m (d) 2,7-dihydroxynaphthalene 0.3 g
Coating solution 12 (a) Binder polymer (polyester, adhesive 4
9000 DuPont, product name) eoo g (b) Hydrazone of formula (2) 300 g (c) Chloroform 3000 m (d) 1.5
-Dihydroxynaphthalene 0.3 g Coating solution 13 (a) Binder polymer (polyester, NAP resin, manufactured by Kanekabuchi Kagakucho Co., Ltd.) soo g (b) Formula (2
) hydrazone 300g (c) Dichloromethane 3000m (d) 1,5-dihydroxynaphthalene 0.3g Next, for comparison, photoreceptors 1 to 13 of Examples except that no deterioration inhibitor was added
Comparative example photoreceptor lots 113 were prepared comprising the same components as in Example 1. The light attenuation characteristics of these photoreceptors were determined by GENTEC
The zero surface potential was measured using a light attenuation characteristic measurement system manufactured by TREC Corporation, and was measured using a high-speed surface potentiometer equipped with a 362A translucent probe manufactured by TREC Corporation.
It was stored in a type 2 digital memory and analyzed.

The obtained results are shown in FIG. 2 and Tables 1 and 2. FIG. 2 shows the photoreceptor 1 of the example prepared using the coating solution 1.
This is a comparison of the response characteristics of photoreceptor 101 as a comparative example and photoreceptor 101 prepared using a solution that does not contain a deterioration inhibitor.
Curve A is the case when 1,5-dihydroxynaphthalene was added, and curve a is the case when 1,5-dihydroxynaphthalene was not added. The exposure conditions in Figure 2 are 800 nm, 150 p, W/cm
The light of No. 2 was irradiated for 20 m5 ec.

As shown by the curve A in Figure 2, the presence of the deterioration inhibitor increases the response speed, and the time it takes for the initial potential of 800V to decay to 100V is 0.13 seconds, but the curve a without the deterioration inhibitor In this case, it took about 1.8 seconds.

The data in FIG. 2 is for a photoreceptor prepared using a coating solution that was prepared, placed in a transparent glass container, and left to stand under room light for one week. Furthermore, the presence of the anti-deterioration agent had no adverse effect on other characteristics other than the response speed.

In addition, Fig. 3 shows the discharge characteristics caused by light when a light pulse of 20 m5ec is irradiated by changing the exposure power (Photo
Induced Discha-rge Cu
Similarly to FIG. 2, the curve d shows the deterioration inhibitor 1
．． In the presence of 5-dihydroxynaphthalene, curve C
does not contain deterioration inhibitors. The surface potential used was the value 0.5 Sec after the light pulse irradiation. From Figure 3, the sensitivity expressed by the half-exposure product of curve d is 0.4 gJ/c.
m2, but the song mc is 0.9 pJ/cm2,
Sensitivity was higher in the presence of anti-deterioration agent.

The following Table 1 shows the characteristics of photoreceptors 1 to 13 of Examples, and Table 2 shows the characteristics of photoreceptors of Comparative Examples using no deterioration inhibitor.

The values in these tables are for coated photoreceptors after the coating solution was prepared, placed in a transparent glass container, and left under room light for one week.

A photoreceptor to which dihydroxynaphthalene or a derivative thereof is added as a deterioration inhibitor, such as photoreceptor 1-13 with L enlargement 1, has a significantly faster response speed and higher sensitivity. Furthermore, the residual potential also becomes a small value. The reason for this is thought to be that traps due to deterioration products of the charge transport material in the charge transport layer are reduced and charge transport is performed efficiently. That is, the additive of the present invention works effectively to suppress the decomposition of the charge transport material and the solvent.

Table 1 Table 2 The above-mentioned embodiments were explained using an example in which an electrophotographic photoreceptor having a structure in which a charge generation layer and a charge transport layer were sequentially laminated on an aluminum base material was used. However, as shown in FIG. 4, the electrophotographic photoreceptor of the present invention may have a structure in which a charge transport layer is provided on an aluminum base layer and a charge generation layer is provided on this charge transport layer. In such a case, an overcoat layer 14 is provided on the charge generation layer to provide printing durability to the electrophotographic photoreceptor and to enable charge transport. This overcoat layer 14 can be formed by coating a solution in which a binder polymer and, for example, trinitrofluorenone are mixed in a weight ratio of 1:1 and dissolved in, for example, tricrene. Moreover, it is suitable that the layer thickness of this overcoat layer is 2 to 3 gm.

Incidentally, polyester or polycarbonate '3 can be used as the binder polymer for this overcoat layer.

(Effects of the Invention) - As explained above, the electrophotographic photoreceptor of the present invention has - dihydroyacinaphthalene or a derivative thereof represented by the general formula (1) added to the charge transporting portion as a deterioration inhibitor. As a result, the response characteristics and sensitivity of the photoreceptor can be dramatically improved.

Additionally, in the past, after preparing a coating solution for a charge transport material, the coating solution deteriorated over a long period of time.
It has been extremely difficult to manufacture photoreceptors of stable quality, but by adding the anti-deterioration agent according to the present invention to a coating solution, it is possible to stably manufacture photoreceptors of excellent quality over a long period of time.

Furthermore, since the charge transporting portion of the photoreceptor after coating contains the reducing agent, which is the deterioration preventing agent, it is possible to prevent oxidation caused by oxygen, ozone, and the like.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the photoreceptors of Examples and Comparative Examples, and FIG. 2 is a curve diagram showing the light attenuation characteristics of Photoreceptors 1 and +01. FIG. 3 is a curve diagram showing the discharge characteristics of the photoreceptors 1 and 101 due to light, and FIG. 4 is a sectional view showing another embodiment of the photoreceptor of the present invention. 11... Aluminum base material 12... Indium phthalocyanine vapor deposited layer 13...
Charge transport layer 14: overcoat layer. Patent applicant Agent: Oki Electric Industry Co., Ltd.
Takashi Ogaki as patent attorney. J' ll Aluminum Fujifuyu 1 12 Indium Fluoride 0 Cyanine Cup Base Layer 13 Electrolysis Hall 1 Pengta This '18 month power official υ month 1 Nii o 1 ro province each T summer tft,,
Light (J9 page) 1st chart db Muro: fL (v)

Claims (5)

[Claims] (1) In a functionally separated electrophotographic photoreceptor in which a charge generation part and a charge transport part are formed using separate materials on a conductive support, the charge transport part has the following general formula, ▲ There are mathematical formulas, chemical formulas, tables, etc.▼...(1) (R_1, R_2, R_3, R_4, R_5, R in the formula
Two or more of _6, R_7, and R_8 are the same or different, and are hydrogen atoms, halogen atoms, hydroxyl groups, amino groups, amino groups substituted with alkyl groups or acyl groups, lower alkyl groups, aryl groups, An electrophotographic photosensitive method characterized in that dihydroxynaphthalene or a derivative thereof represented by acyloxy group, alkoxy group, and any two of R_1 to R_8 always represent a hydroxyl group is added as a deterioration inhibitor. body. (2) The deterioration inhibitor is 1,5-dihydroxynaphthalene,
1,7-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 2,
The electrophotographic photoreceptor according to claim 1, which is 7-dihydroxynaphthalene. (3) When manufacturing a functionally separated electrophotographic photoreceptor in which a portion that generates a charge and a portion that transports a charge are formed on separate materials on a conductive support, the charge transport layer is made of a charge transport material. The following general formula, ▲mathematical formula, chemical formula, table, etc. are found in a solution of binder polymer and binder polymer dissolved in an organic solvent▼...(1) (R_1, R_2, R_3, R_4, R_5, R
_6, R_7 and R_8 are two or more of the same or different, and are hydrogen atoms, halogen atoms, hydroxyl groups, amino groups, alkyl groups or amino groups substituted with acyl groups, lower alkyl groups, aryl groups, acyloxy dihydroxynaphthalene or its derivatives (representing a group, alkoxy group, and any two of R_1 to R_8 always represent a hydroxyl group) are added as a deterioration inhibitor and used as a coating solution, and coated on a conductive support. Alternatively, a method for producing an electrophotographic photoreceptor, which comprises coating and drying the charge generation layer on a conductive support. (4) The method for producing an electrophotographic photoreceptor according to claim 3, wherein an anti-deterioration agent is added to the coating solution in an amount of 0.0001% by weight or more based on the total of the charge transport material, binder polymer, and solvent. (5) As a deterioration inhibitor, 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene,
The method for producing an electrophotographic photoreceptor according to claim 3 or 4, using 2,7-dihydroxynaphthalene.