JPS6350848A - Electrophotographic sensitive body for positive charging - Google Patents

Abstract

PURPOSE:To improve the scratch resistance and durability and to provide superior resistance to oxidation by ozone by incorporating an electric charge transferring substance into the electric charge generating layer and a specified compd. into the generating layer or the protective layer. CONSTITUTION:An electric charge transferring layer 2 and an electric charge generating layer 3 are laminated on an electrically conductive support 1 and a protective layer 7 is formed on the layer 3 as required. The electric charge generating layer 3 contains an electric charge transferring substance 5b and the layer 3 or the protective layer 7 contains a compd. represented by formula I (where each of R1-R4 is H, alkyl, cycloalkyl or aryl). When the substance 5b is a styryl or hydrazone compd., a more significant effect is shown. The pref. thickness of the layer 3 is 2-7mum. Since the compd. represented by the formula I prevents the deterioration of the substance 5b by ozone by self- oxidation, the compd. is preferably incorporated into the protective layer 7 formed on the layer 3 as required but it may be incorporated into the layer 3 or may be further incorporated into the layer 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor, and particularly to a positively charging photoreceptor.

[Conventional technology]

Conventionally, for example, as an electrophotographic photoreceptor, a photoreceptor having a photosensitive layer containing an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide has been widely used.

On the other hand, the use of various organic photoconductive substances as materials for photosensitive layers of electrophotographic photoreceptors has been actively developed and researched in recent years.

For example, in Japanese Patent Publication No. 50-10496, poly-N
-vinylcarbazole and 2.4,7. -1-Linitro=
A photosensitive material having a photosensitive layer containing 9-fluorenone is described. However, this photoreceptor is not necessarily satisfactory in sensitivity and durability. In order to overcome these drawbacks, attempts have been made to develop organic photoreceptors with high sensitivity and durability by assigning charge generation and charge transport functions to different materials in the photosensitive layer. being done.

Furthermore, in so-called functionally separated electrophotographic photoreceptors, it is possible to select substances that exhibit each function from a wide range of materials, so it is relatively easy to produce an electrophotographic photoreceptor with arbitrary characteristics. It is possible to do so.

Many substances have been proposed as charge-generating substances that are effective for such functionally separated electrophotographic photoreceptors. Examples of using inorganic substances include, for example, Japanese Patent Publication No. 43-1619
As described in Publication No. 8, there is amorphous selenium, which is combined with an organic charge transport material.

In addition, many electrophotographic photoreceptors using organic dyes or organic pigments as charge-generating substances have been proposed.
-37543, 55-22834, 54-79
This is already known from publications such as No. 632 and No. 56-116040.

By the way, the conventional photoreceptor using the organic photoconductive substance is usually used for negative charging.

The reason for this is that when using a negative charge, the mobility of holes among the charges is large, so there is an advantage in terms of photosensitivity, etc. However, when using such a negative charge, the following It has been found that there are problems such as: In other words, when negatively charged by a charger, ozone is likely to be generated in the atmosphere, worsening the environmental conditions.Furthermore, another problem is that A positive polarity toner is required for the development of the image, but the positive polarity toner is difficult to manufacture in view of the triboelectrification series with respect to ferromagnetic charged particles.

Therefore, it has been proposed to use a positively charged photoreceptor using an organic photoconductive substance. For example, when a photoreceptor is formed by laminating a charge transport layer on a charge generation layer, a material with a high electron transport ability, such as trinitrofluorenone, is added to the charge transport layer in order to efficiently cancel the positive charge on the surface of the photoreceptor. However, the substance is carcinogenic and extremely unsuitable from a pollution standpoint.

Furthermore, as a positive charging photoreceptor, U.S. Patent No. 361541
Specification No. 4 discloses a material containing a thiapyrylium salt (charge generating substance) so as to form a eutectic complex with polycarbonate (binder resin). However, this known photoreceptor has the drawbacks of a large memory phenomenon and a tendency to generate ghosts. Also US Patent No. 33579
No. 89 also discloses a photoreceptor containing phthalonanine, but phthalocyanine has the disadvantage that the characteristics change depending on the crystal type, and the crystal type must be strictly controlled. The phenomenon is large,
Since the sensitivity to short wavelengths is low, it is considered unsuitable for copying machines that emit visible light including the short wavelengths.

Although various attempts have been made to obtain positive charging photoreceptors, they all have many shortcomings that need to be improved in terms of photosensitivity, memory, pollution, etc.

Therefore, a laminated structure in which the upper layer (surface layer) is a charge-generating layer containing a charge-generating substance that generates holes and electrons when irradiated with light, and the lower layer is a charge-transporting layer containing a charge-transporting substance that has a hole-transporting function. It is conceivable to use a photoreceptor having a photosensitive layer for positive charging.Furthermore, a photoreceptor having a single-layer photosensitive layer containing a retransferable charge generating material and a retransferring charge transporting material may also be used for positive charging. It is considered possible to use such a photoconductor for positive charging.If a charge generating substance having, for example, an electron-withdrawing group is used in the structure, the photoconductor can be used to cancel the positive charge on the surface of the photoconductor. This is thought to be due to faster electron movement and higher sensitivity characteristics.

However, since all of the positive charging photoreceptors have a layer containing a charge-generating substance formed as a surface layer, the charge-generating substance is sensitive to external effects such as light irradiation, corona discharge, humidity, and especially mechanical friction. Since they are present near the surface layer, electrophotographic performance deteriorates during storage of the photoreceptor and during image formation, resulting in low image quality.

In a conventional negative charging photoreceptor having a charge transport layer as a surface layer, the effects of the various functions described above are extremely small, and rather, the overlapping charge transport layer has an effect of protecting the underlying charge generation layer. ing.

On the other hand, in the case of a positively charging photoreceptor, the surface layer containing a charge-generating substance is subject to mechanical thickness and damage due to external effects, especially development and cleaning, resulting in images such as white spots and white streaks. Defects and other deterioration of electrophotographic performance such as surface potential, sensitivity, memory, residual potential, etc. will occur.

Therefore, it is conceivable to provide a thin protective layer made of an insulating and transparent resin to reinforce the layer containing the charge-generating substance, but the protective layer blocks the charges generated during light irradiation, resulting in photoconductivity. The problem is that the information is lost.

Furthermore, it is possible to improve the wear resistance and scratch resistance of the charge generation layer by increasing the thickness of the charge generation layer serving as the surface layer, but there is a problem in that an increase in the thickness leads to a decrease in sensitivity.

[Purpose of the invention]

Therefore, an object of the present invention is to provide an electrophotographic photoreceptor that is suitably configured for positive charging using an organic photoconductive substance, has excellent scratch resistance, high sensitivity, and durability, and also has excellent resistance to ozone oxidation. There is a particular thing.

[Structure and effects of the invention]

An object of the present invention is to provide an electrophotographic photoreceptor in which a charge transport layer, a charge generation layer and, if necessary, a protective layer are sequentially laminated on a conductive support, the charge generation layer containing a charge transport substance, and a charge transport material. This is achieved by a positively charging electrophotographic photoreceptor containing a compound represented by the following general formula in the generating layer or protective layer.

In the general formula, RIq R*, R3 and R4 each represent a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group.

Note that the effects of the present invention are more effectively exhibited when the charge transport substance is a styryl-based or hydrazone-based compound.

Further, it is preferable that the charge generation layer has a thickness of 2 to 7 μl.

As described in the prior art, in a positively charging photoreceptor using an organic photoconductive substance, a charge generation layer (hereinafter referred to as CG
Since the CGL layer (sometimes abbreviated as L) forms the surface layer, it lacks scratch resistance, and in order to improve durability, it is necessary to increase the thickness of the CGL film. However, thickening the pattern causes a decrease in sensitivity. As a means of suppressing this decrease in sensitivity, there is the addition of a charge transport material (hereinafter sometimes abbreviated as CTM) to CGL, but this CTM has a higher biozone oxidation rate than a charge generating material (hereinafter sometimes abbreviated as CGM). Since it has a structure that easily absorbs ozone, it is easily deteriorated by ozone and the durability of the photoreceptor is impaired.

As a result of extensive studies regarding the improvement of ozone deterioration properties, the present inventors have discovered that the above deterioration can be significantly reduced by incorporating a p-7 nylene diamine derivative into the CGL, which is the surface layer of a positive charging photoreceptor. The present invention has been accomplished.

Although the details of the action and effect are unknown, ozone acts on the compound of the present invention before degrading the CTM in the CG.
It is believed that CTM is protected by guarding against further ozone oxidation.

Since the compound of the present invention prevents ozone deterioration of CTM by its own oxidation, a protective layer (
In a photoreceptor equipped with a charge transport layer (hereinafter sometimes abbreviated as OCL), it is of course added to the CGL, but it may also be added to the CGL, and a charge transport layer (hereinafter abbreviated as CTL) mainly composed of CTM is added to the CGL. ) may also be added.

The present invention will be described in more detail below.

The p-phenylenediamine derivative represented by the above general formula, which is added to the charge generation layer of the present invention, is known as an antioxidant and is easily available commercially.

In the general formula, the alkyl group represented by R,, R,, R, or R4 may be linear or branched, or may be substituted, and is preferably an alkyl group having 1 to 8 carbon atoms. be. Specifically, methyl group, ethyl group, propyl group, i-propyl group, butyl group, i-butyl group, 5ea-butyl group, pendel group, hexyl group, octyl group, 2-ethylhexyl group, 2-cyanoethyl group, 3-cyanopropyl group, 5-
Examples include cyanopentyl group.

The cycloalkyl group represented by R7-R4 is preferably a cycloalkyl group having 3 to 8 carbon atoms, such as a cyclopentyl group or a cyclohexyl group.

As the aryl group represented by R, -R, a phenyl group is preferable.

Particularly preferred compounds of the present invention are compounds in which at least two or more of RI to R4 are substituted with substituents other than hydrogen.

Typical specific examples of compounds preferably used in the present invention are shown below, but the invention is not limited thereto.

When used in CGL, the amount of the compound of the present invention added is 0.1 to 100% by weight, preferably 1 to 50% by weight, particularly preferably 5 to 25% by weight, based on the CTM in CGL. be. Moreover, when used in OCL, it is 0.1 to 100% by weight, preferably 1 to 50% by weight based on the binder (3 fats) in OCL.

Next, the structure of the photoreceptor of the present invention will be explained with reference to the drawings. As a photoreceptor, for example, as shown in FIG. 1, a charge transport layer 2 having a CTM and a binder resin as required is placed on a support 1 (a conductive support or a sheet with a conductive layer). As shown in FIG. 2, a photosensitive layer 4 of a laminated structure with a charge generation layer 3 containing CGM, CTM, and binder resin as an upper layer is provided as a lower layer, and as shown in FIG. A protective layer (OCL) 4 is provided on the substrate, and a photosensitive layer 4 of a single layer structure containing CGM, CTM and, if necessary, a binder resin is provided on a support as shown in FIG. However, an OCL may be provided on the photosensitive layer having a single layer structure as shown in FIG. 3, or an intermediate layer may be provided between the support and the photosensitive layer.

Next, as the charge generating material suitable for the present invention, any of inorganic pigments and organic dyes can be used as long as it absorbs visible light and generates free charges. In addition to inorganic pigments such as amorphous selenium, trigonal selenium, selenium-arsenic alloy, selenium-tellurium alloy, cadmium sulfide, cadmium selenide, cadmium selenide sulfide, mercury sulfide, lead oxide, lead sulfide, the following representative examples You can use a fixed pigment as shown in .

(1) Monoazo pigment, polyazo pigment, metal complex azo pigment, pyrazolone azo 1! Azo pigments such as FJl family, stilbene azo and thiazole azo pigments.

(2) Perylene pigments such as perylene anhydride and perylene imide.

(3) anthraquinone derivatives, anthorone derivatives, dibenzpyrenequinone derivatives, vilantrone derivatives,
Anthraquinone or polycyclic quinone pigments such as violanthrone derivatives and iso and oranthrone derivatives (4) Indigoid pigments such as indigo derivatives and thioindigo derivatives (5) Phthalocyanine raw materials such as metal phthalocyanine and metal-free phthalocyanine (6) Diphenylmethane pigment Carbonium pigments such as , triphenylmethane pigments, quinanthene pigments and acridine pigments (7) Quinoneimine pigments such as azine pigments, oxazine pigments and thiazine n pigments (8) Methine pigments such as cyanine pigments and azomethine pigments (9) Quinoline Type IIR pigments (10) Nitro pigments (11) Nitroso pigments (12) Benzoquinone and naphthoquinone pigments (1
3) Naphthalimide pigments (14) Perinone pigments such as bisbenzimidazole derivatives Various azo pigments having electron-withdrawing groups are used because of their good electrophotographic properties such as sensitivity, memory phenomenon, and residual potential. However, polycyclic quinone pigments are most preferred in terms of ozone resistance.

Although the details are unknown, this is probably because the azo group is easily susceptible to ozone acid and the electrophotographic properties deteriorate, whereas polycyclic quinones are inert to ozone.

Examples of the azo pigments used in the present invention include those shown in the following exemplary compound groups [I] to (V).

Exemplified compound group [■]: Exemplified compound group [■]: Exemplified compound group [■]: Exemplified compound [■]: Exemplified compound [V]: □□□□□-It also consists of the following polycyclic quinone pigments. Exemplary compound group [
, ] ~ [■] are the most preferable example compound group [■] as CGM: Req-indicated compound group [■]: Below (margins\, (・/ Exemplary compound group [■]): Next used in the present invention Possible charge transport substances include, but are not particularly limited to, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidasilone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline derivatives, oxacilone derivatives, benzothiazole derivatives, benzimidazole derivatives, quinazoline derivatives,
These may include benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, and the like.

However, in addition to having an excellent ability to transport holes generated during light irradiation to the support side, a substance suitable for combination with the carrier generating substance is preferably used, and such a C T M
For example, still compounds shown in the following exemplified compound group (■) or (X) are used.

Exemplary compound group CI: In addition, as CTM, the following exemplary compound group (XI 3 to [
Hydrazone compounds of the formula XV:l can also be used.

Exemplary compound group [luck]: Exemplary compound group [■] Exemplary compound group (XI Pyrazoline compounds can also be used.

Exemplary Compound Group [XVI): In addition, amine derivatives shown in the following Exemplary Compound Group [X■] 1 can also be used as CTMs.

Exemplary compound group [X■]: Next, the binder W [which may be used in the present invention] is a binder with a volume resistance of 10"Ω.6m or more, preferably 1010Ω.
A transparent resin having a resistance of e1 m or more, more preferably 10 13 Ω·am or more is used. Further, the binder contains at least 50% by weight of a resin that is cured by light or heat.

Such resins that harden with light or heat include, for example, thermosetting acrylic resins, silicone resins, epoxy resins, urethane (A resins, urea resins, phenol resins, polyester resins, alkyd resins, melamine resins, photocurable/cinnamic acid resins, etc.). There are resins, etc. or copolymerized or cocondensed resins thereof, and in addition, all of the photo- or thermosetting resins used in the electrophotographic material f1 are used. For the purpose of (preventing cracks, imparting flexibility, etc.)
The thermoplastic resin can be contained in an amount of 50% by weight according to the above. Such thermoplastic resins include, for example, polypropylene, acrylic resin, methacrylic resin, salt 1
Hivinyl resin, vinyl acetate resin, epoxy resin, butyral resin, polycarbonate resin, silicone resin, or copolymer resins thereof, such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer Polymeric organic semiconductors such as polymeric resins, poly-N-vinylcarbazole, and other thermoplastic resins used in electrophotographic materials can all be used.

Further, the protective layer may contain an electron-accepting substance,
In addition, if necessary, an ultraviolet absorber or the like may be included for the purpose of protecting the CGM, which is dissolved in a solvent together with the binder, applied by dip coating, spray coating, blade coating, roll coating, etc., and dried to form a 2μ layer. Hereinafter, it is preferably formed to have a thickness of 1 μm or less.

The layer structure of the photosensitive layer of the photoreceptor of the present invention has a laminated structure and a six-layer structure as described above, but the charge transport layer, charge generation layer, or protective layer is used to improve sensitivity, residual potential, or to prevent repeated use. For the purpose of reducing fatigue, etc., one or more types of electron-accepting substances can be contained.

Examples of electron-accepting substances that can be used in the present invention include succinic anhydride, maleic anhydride, dibromaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, 3-nitrophthalic anhydride, 4- Nitrophthalic anhydride, pyromellitic anhydride, merellitic anhydride
acid, tetracyanoethylene, tetracyanoquinodimethane, 0-dinitrobenzene, --dinitrobenzene, 1,
3゜5, -trinitrobenzene, varanitrobenzonitrile, picryl chloride, quinone chlorimide, chloranil, brumanil, 2-methylnaphthoquinone, dichlorodicyanobarabenzoquinone, anthraquinone, dinitroanthraquinone, trinitrofluorenone, 9-fluorenonedene[dicyano] methylenemalonodinitrile],
Polynitro-9-fluorenonedene [dicyanomethylenemalonodinitrile], picric acid, 0-nitronone, 0
．． Froic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-2-rosalicylic acid, 3,5-dinitrosalicylic acid, phthalic acid, and the like.

Examples of binder resins that can be used in the photosensitive layer in the present invention include polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, and polycarbonate resin. , addition polymerization type resins such as silicone resins and melamine resins, polyaddition type resins, polycondensation type resins, and copolymer resins containing two or more of the retardation units of these resins,
Examples include insulating resins such as vinyl chloride-vinyl acetate copolymer resin and vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, as well as polymeric organic semiconductors such as poly-N-vinylcarbazole.

Next, the conductive support supporting the photosensitive layer is a metal plate made of aluminum, nickel, etc., a metal drum or metal foil, a plastic film deposited with aluminum, tin oxide, indium oxide, etc., or paper coated with a conductive substance. , a film or drum of plastic or the like can be used.

The charge transport layer is provided by a method in which CTM described above is dissolved or dispersed in a suitable solvent alone or together with a suitable binder resin, and then coated and dried.

Examples of solvents used to form CTL include N, N
-dimethylformamide, benzene, toluene, xylene, monochlorobenzene, 1,2-dichloroethane, dichloromethane, 1,1,2-trichloroethane, tetrahydrofuran, methyl ethyl ketone, ethyl acetate, butyl acetate and the like.

The thickness of the formed CTL is preferably 5 to 50 μm,
Particularly preferred is the 5-30μ end.

CTM per 100 parts by weight of binder resin in CTL is 2
The amount is 0 to 200 parts by weight, preferably 30 to 150 parts by weight.

If the CTM content is less than this, the photosensitivity will be poor and the residual potential will tend to be high, and if it is more than this, the solvent solubility will be poor.

The charge generation layer is formed in the same manner as in the case of CTL by coating the above-described CGM and CTM separately or together or dissolving or dispersing them together in a suitable solvent alone or together with a suitable binder resin and drying. can do.

When CGL is formed by dispersing the above CGM, it is preferable that the CGM is in the form of powder with an average particle size of 2 μm or less, preferably Lμm or less. As the dispersion of toner particles worsens, some of the particles protrude from the surface, resulting in poor surface smoothness, and in some cases, discharge may occur at the protruding portions of the particles, or toner particles may adhere there, resulting in l-toner filming phenomenon. is likely to occur.

However, if the above particle size is too small, it tends to aggregate,
It is desirable to set the lower limit of the average grain size to 0.01 μm because the resistance of the layer increases, the sensitivity and repeatability decrease due to an increase in crystal defects, or there is a limit to miniaturization.

CGL can be provided by the following method.

That is, the above-mentioned CGM is made into IR fine particles in a dispersion medium using a ball mill, a homomixer, etc., and a binder resin and CTM3 are added, mixed and dispersed, and the resulting dispersion is applied. In this method, the (T'
- Uniform dispersion is possible when particles are dispersed downstream.

CGM is 20 to 200 parts by weight, preferably 25 to 100 parts by weight, and CTM is 20 to 200 parts by weight, preferably 30 to 100 parts by weight, per 100 fi of binder resin in CGL.
The amount is 150 parts by weight.

If the amount of CGM is less than this, the photosensitivity will be low and the residual potential will increase, and if it is more than this, the dark decay will increase and the acceptance potential will decrease.

The thickness of the CGL formed as described above is preferably 1 to 10 μm, particularly preferably 2 to 7 μm.

In the case of RRfN composition, the IF of CGL and CTL (the ratio is preferably 1:(1 to 30)).

In the case of the single layer structure, the charge generating substance is contained in the binder resin at a ratio of 20 to 200 parts by weight, preferably 25 to 100 parts by weight, per 100 parts by weight of the binder resin.

If the content of the charge generating substance is less than this, the photosensitivity will be low and the residual potential will increase, and if it is more than this, the dark decay and acceptance potential will decrease.

Next, the amount of the charge transport substance contained in the binder resin is 20 to 100 parts by weight per 100 parts by weight of the binder resin.
The amount is 200 parts by weight, preferably 30 to 150 parts by weight.

If the content ratio of the charge transport substance is less than this, the optical intensity will be poor and the residual potential will tend to be high, and if it is more than this, the solvent solubility will be poor.

The weight ratio of the charge transporting substance H to the charge generating substance in the single-layer photosensitive layer is preferably 1:3 to 1:2.

〔Example〕

The present invention will be explained below with reference to Examples, but the embodiments of the present invention are not limited thereby.

Example 1 Vinyl chloride-vinyl acetate-
Maleic anhydride copolymer (S-LEC MF-10.fa
An intermediate layer having a thickness of 0.1 .mu.m was formed.

Next, polycarbonate resin (Panlite L-1250
, manufactured by Banjin Kaseisha)/CT M (ff -75) = 1
1 and 2 containing 16.5% by weight of 00/75 (weight ratio)
- Apply dichloroethane solution on the intermediate layer by dip coating,
A charge transport layer having a thickness of 5×1×11 was formed. Next, CGM
It was sublimated as 4,10-dibrom anthron (
CTM (ff-75) Panlight L-1250
75 weight 1% for and 10 for CTM! ! !
i% of exemplified compound (14) was added. A dispersion prepared by adding monochlorobenzene to this solution to give a 1.2-dichlorobenzene/monochlorobenzene ratio of 7/3 (body ratio) was spray coated onto the CTL and dried to a 5μ
An f-based photoreceptor of the present invention having a photosensitive layer having a laminated structure was obtained by forming a charge generating layer of m.

Comparative Example 1 A comparative photoreceptor was obtained in exactly the same manner as in Example 1 except that Exemplary Compound (14) was omitted.

Example 2 A photoreceptor was obtained in exactly the same manner as in Example 1, except that Exemplified Compound (5) was used in place of Exemplified Compound (14).

Example 3 Brimer PII91 for silicone hard coat (manufactured by Toshiba Silicon Co., Ltd.) was spray-coated to a thickness of 0.1 μm on the photosensitive layer excluding the exemplified compound (14) of Example 1, and silicone hard coat was further applied on top of the photosensitive layer excluding the exemplified compound (14). court toss guard 510
<*Shiba Silicon Co., Ltd. WJJ) and exemplified compound m (14)
A solution containing 10 parts by weight based on n parts of the resin room was spray-coated and dried to form a film having a thickness of 1 μT to obtain a photoreceptor.

Example 4 Vinyl chloride-vinyl acetate-
Maleic anhydride copolymer (S-LEC MF-10,
An intermediate layer having a thickness of about 0.1 μm was formed.

Next, as a coating liquid for CTL, butyral resin (S-LEC BX-1, manufactured by Tsukisui Kagaku Co., Ltd.) 81% and CTM ([
X-75) A coating solution obtained by dissolving 6% by weight in methyl ethyl ketone is applied onto the intermediate layer and dried to a thickness of 10μ.
0-order CGM with m-thick charge transport layer (■ 7)
Apply 0.2S+ to paint conditioner (r'aint
Conditioner, manufactured by Red Devi1)
Grind for 30 minutes, and add polycarbonate resin (Panlite L-1250, mentioned above) to it in 1,2-dichloroethane/
0.53M9 in 1,1,2-trichloroethane mixed solvent
8.3g of the solution was added and dispersed for 3 minutes, and then polycarbonate resin, CTM
(IX 75) and the disclosed compound (14) at 7″L3, 3x%, 2,6!IX% and 0.2%, respectively.
A solution t9. obtained by dissolving in a mixed solvent of 1,2-dichloroethane/1,1.2-trichloroethane so that 6fii',,' is obtained. ty was added and the mixture was further dispersed for 300 minutes. The thus obtained dispersion was spray coated onto the CTL and dried to form a charge generating layer with a thickness of 5 μm, thereby obtaining a photoreceptor having a photosensitive layer having a stacked N structure.

Comparative Example 2 A comparative photoreceptor was obtained in exactly the same manner as in Example 4 except that Exemplary Compound (14) was omitted.

Example 5 A photoreceptor was obtained in exactly the same manner as in Example 4, except that Exemplified Compound (5) was used in place of Exemplified Compound (14).

Example 6 A protective layer containing the same exemplified compound (14) as in Example 3 was installed on the photosensitive layer (same as the photoreceptor of Comparative Example 2) except for the exemplified compound (14) in Example 4, Sensitivity f↑: was obtained.

The ozone resistance of the photoreceptor sample obtained as described above was evaluated using the following ozone fatigue tester.

In other words, the electrical evaluation tester (Kawaguchi Electric manufactured rupture 5P-428
type) and an ozone generator (0-1-2 manufactured by Japan Ozone Co., Ltd.)
type) and ozone monitor (EG manufactured by Ebara Jitsugyo Co., Ltd.)
-2001 model) was used.

Attaching the photoreceptor at an ozone concentration of 90 ppm, +6K
After applying a voltage of V and charging the photosensitive layer by corona discharge for 5 seconds, it was left for 5 seconds (the potential at this time was set to the initial potential V0).
Then, light from a tungsten lamp was irradiated with the surface of the photosensitive layer at an illuminance of 14 lux, and this operation was repeated 100 times.

When the potential after 100 irradiations is vl, V, /V. ×1
Ozone resistance was expressed as 00 (%). V, /V, is 100
This indicates the degree of potential drop after repetition, and the higher the value, the better.The results are shown in the separate table.

It can be seen from the attached table that all of the photoreceptors of the present invention have excellent ozone resistance, whereas the comparative photoreceptors are significantly inferior to ozone.

[Brief explanation of drawings]

1 to 3 are cross-sectional views of the positively charging photoreceptor of the present invention. 1... Support 2... Charge transport layer 3... Charge generation layer 11... Photosensitive layer 5... Charge transport material (CTM) 6... Charge generation material (CG, M) 7...Protective layer applicant Konishiroku Photo Industry Co., Ltd. Figure 3

Claims (2)

[Claims] (1) In an electrophotographic photoreceptor in which a charge transport layer, a charge generation layer, and, if necessary, a protective layer are sequentially laminated on a conductive support, the charge generation layer contains a charge transport substance, and the charge generation layer contains a charge transport substance. Alternatively, an electrophotographic photoreceptor for positive charging, characterized in that the protective layer contains a compound represented by the following general formula. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, R_1, R_2, R_3 and R_4 are respectively,
Represents a hydrogen atom, an alkyl group, a cycloalkyl group, or an aryl group. ] (2) Claim 1, wherein the charge transport substance is a styryl-based or hydrazone-based compound.
Electrophotographic photoreceptor for positive charging as described in .