JPS62278561A - Electrophotographic sensitive body and its production - Google Patents

Abstract

PURPOSE:To produce an electrophotographic sensitive body having superior sensitivity and a high response speed by incorporating dihydroxydiphenyl or a deriv. thereof represented by a prescribed general formula into a charge transferring part as a deterioration inhibitor. CONSTITUTION:A charge generating part and a charge transferring part are formed on an electrically conductive support with separate materials to produce a separated function type electrophotographic sensitive body. When the charge transferring part is formed with a soln. prepd. by dissolving a charge transferring material and a polymer binder in an org. solvent, dihydroxydiphenyl or a deriv. thereof represented by formula I is added to the soln. as a deterioration inhibitor. In the formula I, each of R1-R10 is H, halogen, hydroxyl, amino, alkyl or acyl substituted amino, lower alkyl, aryl, acyloxy or alkoxy, and two among R1-R10 are hydroxyl. The deterioration inhibitor is added by >=0.0001wt% of the total amount of the charge transferring material, the polymer binder and the solvent.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Industrial Applications! 7) The present invention relates to an electrophotographic photoreceptor, particularly a single-layer separation type electrophotographic photoreceptor with excellent characteristics such as sensitivity and response speed. The present invention relates to a photoreceptor and a method for manufacturing the same.

(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 many documents as disclosed in the above publication. This publication describes the general structure of an organic electrophotographic photoreceptor, in which (a) a photoconductive layer consisting of a charge-generating substance and a charge-transporting medium is provided 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, conversely, a '7rL charge generation layer. A two-layer leading Tt layer with a charge transport layer laminated thereon is disclosed.

On the other hand, "Photography Science and Engineering" by D, M, Pa1 and J, Yanus
g”raphic 5science and Engi
nering) J 27(1), 14~+9(+9
83) describes that a recent trend is to use two-layer laminated structures in which charge generation and charge transport are carried out in two layers laminated on a conductive support. 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. In order to increase the response speed of the photoreceptor, it is necessary to use a material with high carrier mobility, and to increase the ratio of charge transport material to binder polymer. This document reveals that the residual potential is reduced and the contrast potential can be increased.

On the other hand, in the above-mentioned Japanese Patent Application Laid-Open No. 57-148255, in the theory +51 of a photoreceptor having a two-layer structure in which charge generation and charge transport are shared by separate layers, the charge transport material is replaced with an inert resin binder. It is described that a charge transport layer is prepared by coating a homogeneous solution dissolved in a solution of a charge transport layer on a support or a charge generation layer and drying the same. Binder polymers for the charge transport layer include polystyrene, polyvinyl chloride, polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl acetal, alkyd resin, acrylic resin, polyacrylonitrile, polycarbonate, polyamide, polyketone, poly7-acrylamide, and butyral. Examples include resins, esters, polyurethanes, epoxies, and phenolic resins. Examples of organic solvents that can also be dissolved to coat these binder polymers and charge transport materials include benzene, toluene, xylene, chlorobenzene, acetone, methyl ethyl ketone, cyclohexanone, methanol, ethanol, impropatol, ethyl acetate, methyl cellosolve, Carbon tetrachloride, chloroform, dichloromethane, tetrahydrofuran, dioxane, dimethylformamide, and dimethyl sulfoxide are listed.

(Problem to be Solved by the Invention) However, charge transport materials) are often unstable, and especially when they are dissolved in a solvent, they deteriorate during storage, and the photoreceptor after which they are coated does not respond well. Deterioration of characteristics, decrease in sensitivity,
An increase in residual potential often occurred. 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, the present invention prevents 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, electrophotography with improved characteristics such as sensitivity and response speed can be achieved. The object of the present invention is to provide a photoreceptor and a method for manufacturing the same.

(Means for Solving the Problems) The present invention involves adding a specific deterioration inhibitor to a coating solution in which a charge transport material and a binder polymer are dissolved in an organic solvent.
This is based on the finding that Kitami's objective can be achieved by forming a charge transport portion using this coating solution.

Therefore, Kippatsu 11 proposed that in a functionally separated electrophotographic photoreceptor in which the charge generation part and the charge transport part are formed on separate materials on a conductive support, the charge transport part has the following general formula: .

(RJ, R2, R3, R4, Rs, Rh in the formula.

Two or more of RJ, Rs, R9 and R10 are the same or different, and are substituted with a hydrogen atom, a halogen atom, a hydroxyl group, an amino group substituted with an alkyl group such as an amino group, or an acyl group such as lower alkyl groups such as amino groups, aryl groups, acyloxy groups such as -ococH3, alkoxy groups such as -0CH3 and -0C2H5, and any two of R1 to R10 always represent a hydroxyl group) The present invention relates to an electrophotographic photoreceptor characterized in that dihydroxydiphenyl or a derivative of 7 represented by the following formula 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 dihydroxydiphenyl of formula (1) or its derivative is contained in the charge transport material as a deterioration preventive agent. It has the following.

The present invention also relates to a method for manufacturing the above electrophotographic photoreceptor, and this method is a functionally separated type in which a portion that generates a charge and a portion that transports a charge are formed on separate materials on a conductive support. When producing an electrophotographic photoreceptor, the charge transport layer is prepared by adding dihydroxydiphenyl of 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 to form a coating solution. It is characterized in that it is formed by coating and drying on a conductive support or a charge generation layer on a conductive support.

Conventionally used charge transport materials, binder polymers, and organic solvents for forming the coating solution used in the method of the present invention can be used. 0.0001% or more, preferably 0, based on the total mold breakage of the material, binder polymer, and solvent
．． Add 1 to 0.001%. Deterioration prevention W agent is 0.000
1! I! If the amount is less than 14%, the effect of adding it will not be obtained.On the other hand, the upper limit is determined by the solubility in the solvent used, and is usually 14I! 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 lip and the charge transport material is in the range of 4:1 to 1:1 by weight. is preferable.

Generally, when additives are added to the coating solution used to form the charge transport layer, the characteristics of the photoreceptor produced often deteriorate, but the anti-1L agent of the present invention does not have such adverse effects. This dramatically improves the characteristics of the photoreceptor.

(Function) According to the present invention, since the 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 invention is not limited only to numerical conditions and arrangements and relationships.

Example 1 A 0.2 m thick vapor-deposited film of indium phthalocyanine (Japanese Unexamined Patent Publication No. 59-44054) was formed on an aluminum substrate to form a charge generation layer.

On this charge generation layer, a charge generation layer of +5 pm was formed by the Dix coating method using coating solutions 1 to 8 for forming a charge transport layer having the following compositions to obtain electrophotographic photoreceptors 1 to 8 of Examples. Obtained.

The cross-sectional structure of these photoreceptors is shown in Figure 1, 11 out of 9 drawings.
12 is an aluminum base material, 12 is an indium phthalocyanine vapor deposited layer, thickness 0.2 pm, and 13 is a charge transport layer, thickness 1.
It is m for 5.

Coating droplet composition Coating solution l (a) Binder polymer: polyester resin (Vylon 2
00 Toyobo Co., Ltd., product name) soo g (b) TL charge transport material 1,2,3,4-tetrahydroquinoline-6-carboxyaldehyde hydrazone derivative (Japanese Patent Application Laid-open No. Sho Go-148248) (Normal use) 00 g (c) T8 medium: Chloroform (contains 0,5-ethyl alcohol for preventing decomposition) (special grade, manufactured by Kanto Kagaku Co., Ltd.) 2HOm exchange (d) Deterioration prevention I
Agent: 4.4-dihydroxydiphenyl (manufactured by Tokyo Kasei Co., Ltd.) 0.3 g Coating solution 2 (a) Vylon 200 600
g (b) Hydrazone of formula (2) 300
g(c) Dioxane 2500m
Bun cyclohexanone, special grade (manufactured by Kanto Kagaku Co., Ltd.)
500m intersection (d) 4.4°
-Dihydroxidine phenyl 0.3g coating solution 3 (a) Binder polymer, polycarbonate (Lexan 141, manufactured by Engineering Plastics Co., Ltd.,
Product name) 400 g (b) Hydrazone of formula (2) 400 g (c) Chloroform
2000m or (d) 4.4'-dihydroxydiphenyl 0.3g coating solution 4 (a) Heiron 200 130
0 g (b) Charge transport material: p-diethylaminobenzaldehyde diphenylhydrazone (manufactured by Nayo Fragrance Industry Co., Ltd.) (JP-A-60-146248) 00 g (c) Toluene, ELS (Kanto Kagaku Co., Ltd. S8ri90)
0m methyl ethyl ketone, ELS (manufactured by Kanto Kagaku Co., Ltd.)
300ml butyl acetate, EL
S (manufactured by Kanto Kagaku Co., Ltd.) 00mM cyclohexanone 300ml (d) 4
．． 4'-Dihydroxydiphenyl 0.3g (e) Paint: Silicone oil (KF89 manufactured by Shin-Etsu Chemical Co., Ltd.)
3m coating solution 5 (a) Byron 200 800
g (b) Charge transport material - phenyl-3 (p
-diethylaminostyryl)-5-(p-diethylaminophenyl)-2-pyrazoline (manufactured by Nayo Kosai 1 Sangyo Co., Ltd.) 300 g (c) Chloroform 2000 m
d) 4.4-dihydroxydiphenyl 0.3g coating solution 6 (a) Byron 200 80
0 g (b) Todorashif of formula (2) 300
g(c) Chloroform 2000m
(d) 2.2-dihydroxydiphenyl (manufactured by Tokyo Kasei Co., Ltd.) o, 3g Coating solution 7 (a) Vylon 200 800
g (b) Hydrazone of formula (2) 300
g(c) Chloroform 2000m9
゜(d) 2,5-dihydroxydiphenyl (manufactured by Tokyo Kasei Co., Ltd.) OJg -In i Coating solution 8 (a) Binder polymer (polyester, adhesive 4)
9000 DuPont, product name) 1300 g (Ro)
Hydrazone of formula (2) 300g (c) Chloroform 3000m) 4.4
'-dihydroxydiphenyl 0.3g Next, for comparison, photoreceptor 1 of Example 1 except that no deterioration inhibitor was added.
Photoreceptors 11 to 18 of comparative examples were prepared using the same components as in Examples 1 to 8. The light attenuation characteristics of these photoreceptors were determined by GENTEC
The zero surface potential measured using the optical attenuation characteristic measurement system manufactured by TREC Corporation was measured using a high-speed surface potential meter with a 362A translucent probe manufactured by TREC Corporation, and the results were
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 l of the example prepared using the coating solution 1
The response characteristics of the photoreceptor 11 and the photoreceptor 11 of a comparative example prepared using a solution containing no deterioration inhibitor are compared. Curve A is the case when 4,4°-dihydroxydiphenyl was added, and curve a is the case when 4,4°-dihydroxydiphenyl was not added. The exposure conditions in Figure 2 are 150 g W/cm2 at 800 nm.
The light was irradiated for 20m5ec.

As shown by the curve in Figure 2, the presence of the anti-deterioration IE agent increases the response speed, and the time it takes for the initial potential of 600■ to decay to +00■ is 0.15 seconds, compared to the case without the anti-deterioration agent. In the case of curve a, it took about 1.8 seconds.

The data in Figure 2 is obtained after preparing the coating solution.
+1 The photoreceptor was prepared using a solution that had been placed in a glass container and left in an indoor light room for a week.The presence of an anti-deterioration agent had a negative effect on other properties other than the response speed.
There was nothing to be gained.

In addition, the exposure power was changed to 20m5ec in the 0'S3 figure.
Discharge characteristics due to light (Pho) when irradiated with a light pulse of
to Induced Discha-rge
Similarly to FIG. 2, the curve d indicates the presence of the deterioration inhibitor 4.4'-dihydroxydiphenyl;
Curve C does not contain the deterioration inhibitor.For the surface type, the value 0.5SeC after light pulse irradiation was used.
, from Figure 3, the sensitivity expressed by the half-decreased exposure amount of curve d is 0.5
gJ/cm2, but 1 curve C is 0.9 gJ/c
m2, and the sensitivity was higher in the presence of the deterioration inhibitor.

The following Table 1 shows the characteristics of the photoreceptors 1 to 8 of the examples and Table 2 shows the characteristics of the photoreceptors of the comparative example without antidegradation II: agent.The values in these tables are the values after preparing the coating solution. , a coated photoreceptor that was placed in a transparent glass container and left under room light for one week.

Photoreceptors 1 to 8 in Table 1 above, in which dihydroxydiphenyl or its derivatives are added as a deterioration inhibitor, have a significantly faster response speed and higher sensitivity. Furthermore, the residual potential is also small.

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 Ti and cargo transport are performed efficiently. In other words, the additive of the present invention suppresses the decomposition of the charge transport material and the solvent. The explanation has been given using an example of a photoreceptor. 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 material and a charge generation layer is provided on this charge transport layer. If so, an overcoat (M14) is provided on the charge generation layer, which imparts printing durability to the electrophotographic photoreceptor and is capable of charge transport. This O/H coat layer 14 can be formed by coating with a solution in which the /hainder polymer and, for example, trinitrofluorene are mixed in a weight ratio of 1=1 and dissolved in, for example, trichlene. Also, this o/
It is suitable that the layer thickness of the hew coat layer is 2 to 3 pm. Incidentally, as the binder polymer of this overcoat W, polyester, polycarbonate, etc. can be used.

(Effects of the Invention) As explained above, the electrophotographic photoreceptor of the present invention has the following features:
By adding dihydroxydiphenyl represented by the general formula (1) or a derivative thereof to the TL transport portion as a deterioration inhibitor, 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.

It has been extremely difficult to manufacture photoconductors with stable quality over a long period of time, but by adding the anti-degradation agent of the present invention to the coating solution, it has become possible to stably manufacture photoconductors with excellent quality over a long period of time. can.

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 buildup due to 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, FIG. 2 is a curve diagram showing the light attenuation characteristics of photoreceptors 1 and 11, and FIG. 3 is a curve diagram showing the light-induced discharge characteristics of photoreceptors 1 and 11. The curve diagram: fS4 is a sectional view showing another embodiment of the photoreceptor of the present invention. ! 1... Aluminum base material 12... Indium phthalocyanine kiln bonding layer 13...
Charge transport layer 14: overcoat layer. Patent applicant: Oki Electric Industry Co., Ltd.
Completed) Mini Lamb Kuragegi 1/2 Indium Phthalocyanine Fish Layer/3 Electric De'
fit Ren, stupid iE + moon power official t881″-(Ai 1 and each photo summer, especially Isen's picture 1 surface type set ('V) A side @AfL (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, R_8, R_9 and R_1_0 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, Indicates an aryl group, an acyloxy group, an alkoxy group, and R_
Any two of 1 to R_1_0 must represent a hydroxyl group)
An electrophotographic photoreceptor characterized in that dihydroxydiphenyl or a derivative thereof represented by: is added as a deterioration inhibitor. (2) The electrophotographic photoreceptor according to claim 1, wherein the deterioration inhibitor is 4,4'-dihydroxydiphenyl, 2,2'-dihydroxydiphenyl, or 2,5-dihydroxydiphenyl. (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
Two or more of _6, R_7, R_8, R_9 and R_1_0 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, Indicates an aryl group, an acyloxy group, an alkoxy group, and R_
Any two of 1 to R_1_0 must represent a hydroxyl group)
It is characterized by adding dihydroxydiphenyl represented by or a derivative thereof as a deterioration inhibitor and using it as a coating solution, coating it on a conductive support or a charge generation layer on a conductive support, and drying it. A method for manufacturing an electrophotographic photoreceptor. (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) Production of an electrophotographic photoreceptor according to claim 3 or 4, using 4,4'-dihydroxydiphenyl, 2,2'-dihydroxydiphenyl, or 2,5-dihydroxydiphenyl as a deterioration inhibitor. Method.