JPS6352146A - Positively electrifiable electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body superior in resistances to scratching and ozone oxidation, high in sensitivity and durability, and suitable for positive electrification by incorporating an electric charge transfer material in a charge generating layer, and a specified compound in this layer or a protective layer. CONSTITUTION:The electrophotographic sensitive body is obtained by successively laminating the charge transfer layer, the charge generating layer, and when needed, the protective layer on a conductive substrate, and it contains the charge transfer material in the charge generating layer and in this layer or the protective layer the compound represented by the formula shown on the right in which R is H, alkyl, aryl, or aralkyl and R' is alkyl. When this compound is added to the charge generating layer, it is contained in an amount of 0.1-100wt%, preferably, 1-50wt%, especially, 5-25wt% of the charge transfer material contained in the charge generating layer, and when it is added to the protective layer, it is contained in an amount of 0.1-100wt%, preferably, 1-50wt% of the binder resin of this layer.

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 the photosensitive layer 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, hlinitro-
An organic photoreceptor having a photosensitive layer containing 9-fluorenone is described. However, this photoreceptor is not necessarily satisfactory in terms of sensitivity and durability. In order to overcome these drawbacks, we developed an organic photoreceptor with high sensitivity and durability by assigning the charge generation function and charge transport function to different substances in the photosensitive layer. Attempts are being made.

In such so-called function-separated type 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 electrophotographic photoreceptors with arbitrary characteristics. It is possible to do so.

A large number of substances have been proposed as charge-generating substances that are effective for such f-bifunctional electrophotographic photoreceptors. Examples of using inorganic substances include, for example, Japanese Patent Publication No. 43-161
As described in the '98 publication, 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 negative charging is used, the mobility of holes among the charges is large, which is advantageous in terms of photosensitivity and the like. However, it has been found that using such negative charging causes the following problems. That is, there is a problem in that ozone is likely to be generated in the atmosphere during negative charging by the charger, worsening the environmental conditions. Another problem is that positive polarity toner is required for development of negatively charged photoreceptors, and positive polarity toner is difficult to manufacture due to the triboelectrification system for ferromagnetic charged particles. .

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

Furthermore, as a positive charging photoreceptor, U.S. Patent No. 361541
The specification of No. 4 discloses a method in which a thiapyrylium salt (charge generating substance) is contained so as to form a eutectic complex with polycarbonate (bingu resin). However, this known photoreceptor has the drawbacks of a large memory phenomenon and a tendency to generate ghosts. Also, US Patent No. 3357
No. 989 also discloses a photoreceptor containing phthalonanine, but phthalonanine has the disadvantage that the characteristics change depending on the crystal type and that the crystal type must be strictly controlled. Since the memory phenomenon is large and the sensitivity to short wavelengths is low, it is considered unsuitable for copying machines whose light source is visible light including the short wavelengths.

As described above, various attempts have been made to obtain photoreceptors for positive charging, but all of them have many problems that need to be improved in terms of photosensitivity, memory, pollution, etc.

Therefore, we developed a photosensitive layer with a laminated structure in which the upper layer (surface layer) is a charge generation layer containing a charge generation substance that generates holes and electrons when irradiated with light, and the lower layer is a charge transport layer containing a charge transport substance having a hole transport function. It is conceivable to use a photoreceptor having the above-mentioned structure for positive charging. Furthermore, it is considered that a photoreceptor having seven photoreceptor layers of a single layer structure including the charge generation material and the charge transport material can also be used for positive charging. In addition, in a photoreceptor used for electrical purposes, for example, if a charge generating substance having an electron-withdrawing group is used during groove formation, the electrons that cancel out the positive charge on the surface of the photoreceptor can be generated. It is conceivable that the movement becomes faster and a sensitivity characteristic of Aj is obtained.

However, since a positive charging photoreceptor has a layer containing a charge-generating substance formed as a surface layer, charge generation is sensitive to external effects such as light irradiation, corona discharge, humidity, and especially mechanical friction. The substance will be present in the vicinity of the surface layer, and the electrophotographic performance will deteriorate during storage of the photoreceptor and during the image formation process, resulting in a decrease in 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 charge transport layer has the effect of protecting the underlying charge generation layer. .

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

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. There is a problem of loss of sexuality.

Furthermore, it is possible to improve the abrasion 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 that the 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. It is constituted 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, R represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, and R' represents an alkyl group.

Note that the effects of the present invention are more effectively exhibited when the thickness of the charge generation layer is 2 to 7 μm.

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 (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, increasing the film thickness 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, the present inventors discovered that the above deterioration can be significantly reduced by incorporating the compound of the present invention into CGL, which is the surface layer of a positive charging photoreceptor. I came to do this.

Although the details of the action and effect are unknown, ozone reduces CGL in CGL.
It is believed that CTM is protected by acting on the compound of the present invention before it deteriorates TM and guarding against further ozone oxidation.

Since the compound of the present invention prevents ozone deterioration of CTM by its own oxidation, it is of course possible to use a photoreceptor in which a protective layer (hereinafter sometimes abbreviated as ○CL) is provided on the CGL as necessary. However, it may also be added to CGL, and further may be added to a charge transport layer (hereinafter sometimes abbreviated as CTL) whose main component is CTM.

The present invention will be described in more detail below.

The compound of the present invention represented by the above general formula is 6-alkyl-
It is a 2,3,5-trimethyl-p-phenymu>diamine derivative.

In the general formula, the alkyl group represented by R substituting the amine group may be linear or branched, and preferably has 1 to 1 carbon atoms.
8 alkyl group, specifically methyl group, ethyl group, propyl group, butyl group, 5ec-butyl group, t-butyl group,
Examples include i-pentyl group, hexol group, and -octyl group.

Among these, branched alkyl groups are preferred.

The aryl group represented by R is preferably a phenyl group,
This phenyl group may have a substituent.

Examples of the aralkyl group represented by R include a benzyl group and a phenethyl group, and these groups may also have a substituted bridge.

The alkyl group represented by R' preferably has 1 carbon atom
-18 alkyl groups, particularly preferred are linear alkyl groups having 1 to 12 carbon atoms.

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

When used in OCL, the amount of the compound of the present invention added is 0.1 to 100% by weight based on CTM in CG L;
Preferably it is 1 to 50% by weight, particularly preferably 5 to 25% by weight. Also, when used in OCL, OCL
The amount is from 0.1 to 100% by weight, preferably from 1 to 50% by weight, based on the binder resin therein.

Next, the structure of the photoreceptor of the present invention will be explained with reference to the drawings. The photoreceptor is, for example, a charge transport layer containing CTM and a binder resin as required on a support (a conductive support or sheet with a conductive layer provided on it) as shown in FIG. As shown in FIG.
As shown in the figure, a protective layer (OCL) 4 is provided on the photosensitive layer, and as shown in FIG.
Alternatively, 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 substance 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 Organic pigments such as those shown may also be used.

(1) Azo pigments such as monoazo pigments, polyazo pigments, metal complex azo pigments, pyrazolone azo pigments, stilbene azo and thiazole azo pigments.

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

(3) anthraquinone derivatives, anthanthrone derivatives, dibenzpyrenequinone derivatives, pyrantrono derivatives,
Anthraquinone or polycyclic quinone pigments such as violanthrone derivatives and isohiolanthrone derivatives (, t) Innovo derivatives Innocoid pigments such as thioindigo derivatives (5) Phthalocyanine pigments such as metal phthalonanine and metal-free phthalocyanine (6) Carbonium pigments such as diphenylmethane pigments, triphenylmethane pigments, xanthine pigments and acrinone pigments (7) Quinoneimine pigments such as azine pigments, oxanone pigments and thianone pigments (8) Methine pigments such as cyanine pigments and azomethine pigments (9) Quinoline pigments (lO) Nitro pigments (IT) Nitroso pigments (12) Benzoquinone and naphthoquinone pigments (13)
Naphthalimide pigments (14) Perinone pigments such as bishenzimidazole derivatives Various azo-type pigments having electron-withdrawing groups are used because of their good electrophotographic properties such as pentagonism, memory phenomenon, and residual potential. Polycyclic quinone pigments are most preferred in terms of ozone resistance.

Although the details are unknown, this is probably because azo groups are susceptible to ozone oxidation 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 (1) to [■].

Exemplary compound group [■]: Exemplary compound group [■].

Exemplified compound group [■]: Exemplified compound [■]: Exemplified compound (V)・ Also, an exemplified compound group consisting of the following polycyclic quinone pigments (
vI)~[■] can be most preferably used as CG~i. , 7-1.7.

71 Illustrated compound group (Vl) Illustrated compound group [■]: t'-p? 'y Exemplary compound group [■] Next, there are no particular limitations on charge transport substances that can be used in the present invention, but examples include oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazocone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline derivatives, oxacilone derivatives, benzothiazole derivatives, benzimidazole derivatives, quinaprine 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 the 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, the following exemplified compound group (TX) or [X]
The still compound shown is used.

Exemplary compound group [■]: Exemplary compound group (X) In addition, the following exemplary compound group [η] ~ (XV
) can also be used.

Exemplified compound group [■] Exemplified compound group (XI [l): Exemplified compound group CXV): The following exemplified compound [X■] is used as CTM. Amine derivatives represented by group [X■] can also be used.

Exemplary compound group [X~1] 2 or less q - Protective layer that may be used in the present invention: As a binder, the volume resistivity is 106 Ω·cm or more, preferably 1010 Ω
・A transparent resin having a resistance of 10I3Ω·cm or more, more preferably 10I3Ω·cm or more is used. Further, the surface binder should contain at least 50% by weight of a resin that is facilitated by light or heat.

Examples of such resins that harden with light or heat include thermosetting acrylic resins, silicone resins, Evokin resins, urethane resins, urea resins, phenol resins, polynistyl resins, alkyd resins, melamine resins, and photocurable/cinnamic acid resins. Co-condensation resins are available for copolymerization, and all of the photo- or thermosetting resins used in electrophotographic materials can be used. If necessary, less than 50% by weight of a thermoplastic resin may be added to the protective layer for the purpose of improving workability and physical properties (preventing cracks, imparting flexibility, etc.). Such thermoplastic resins include, for example, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, evoquino resin, butyral resin, polycarbonate resin, silicone resin, or copolymer resins thereof, such as vinyl chloride-vinyl acetate copolymer resin. Polymer resins, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins, polymeric organic semiconductors such as poly-N-vinylcarbazole, and other thermoplastic resins used in electrophotographic materials are all used.

Further, the surface protective layer may contain an electron-accepting substance,
If necessary, the layer may contain an ultraviolet absorber or the like for the purpose of protecting the CGM, and it is dissolved in a solvent together with the above-mentioned ingredients, for example, dipping, spraying, blade coating, roll coating, etc. The layer is coated and dried by coating or the like to have a layer thickness of 2 μm or less, preferably 1 μm or less.

The layer structure of the photosensitive layer of the photoreceptor of the present invention can be classified into a laminated structure and a single layer structure as shown in FIG. For the purpose of reducing fatigue during operation, it is possible to contain IN or two or more types of electron-accepting substances.

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, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane,
0-dinitrobenzene, m-dinitrobenzene,! ,3
゜5, -Trinitrobenzene, varanitrobenzonitrile, picryl chloride, quinone chlorimide, chloranil, brumanil, 2-methylnaphthoquinone, dichlorodicyanobarabenzoquinone, anthraquinone, nnitroanthraquinone, trinitrofluorenone, 9-fluorenonedene [dicyano methylenemalonodinitrile], polynitro-9-fluorenonedene[dicyanomethylenemalotunonitrile], picric acid, 0-nitrobenzoic acid, p-nitrobenzoic acid, 3.5-dinitrobenzoic acid, folic acid,
Pentafluoroamne9, folic acid, 5-nitrosalicylic acid, 3
．． Examples include 5-dinitrosalicylic acid and phthalic acid.

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, Epoquin resin, polyurethane resin, phenol resin, polynistyl fat resin, alkyd resin, and polycarbonate. Addition polymer resins, polyaddition resins, polycondensation resins such as resins, silicone resins, and melamine resins, and copolymer resins containing two or more repeating units of these resins, such as vinyl chloride-vinyl acetate. Examples include insulating resins such as copolymer resins and vinyl chloride-vinyl acetate-maleino acid anhydride copolymer resins, as well as polymeric organic semiconductors such as poly-N-vinylcarbazole.

Next, as a conductive support for supporting the photosensitive layer, a metal plate made of aluminum, nickel, etc., a metal drum or metal foil, a positive film deposited with aluminum, tin oxide, indium oxide, etc., or a conductive material coated. Films or drums such as paper, plastic, etc. can be used.

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

Examples of solvents used to form CTL include N, N
-Dimethylformamide, benzene, toluene, kiln, 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 preferably, it is 5 to 30 μm.

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

If the content of CTM is less than this, the photosensitivity will be poor;
The residual potential tends to become high, and if the amount is more than this, the solvent solubility will deteriorate.

The charge generation layer consists of the previously described CGM and CT〉, 1 separately.
Alternatively, apply a solution dissolved or dispersed in a suitable solvent alone or together with a suitable binder resin,
It can be dried and formed in the same manner as CTL.

When the above-mentioned CGM is dispersed to form a CGL, the CGM is preferably in the form of powder having an average particle size of 2 μm or less, preferably 1 μm or less. That is, if the particle size is too large, dispersion in the layer will be poor, and some of the particles will protrude from the surface, resulting in poor surface smoothness. In some cases, discharge may occur at the protruding part of the particle, or toner may Particles tend to stick and toner filming phenomenon occurs easily.

However, if the grain size is too small, Si will collect more easily, the resistance of the layer will increase, and crystal defects will increase.
Or is the repeatability decreased by 1? 'fi
Since there is a limit to increasing the particle size to +1Ill, it is desirable to set the lower limit of the average particle size to 001 μm.

CG L can be set by the following method. That is, this is a method in which CON2 described above is made into fine particles in a dispersion medium using a ball mill, a mo mixer, etc., a binder resin and CTM are added, and a dispersion obtained by mixing and dispersing is applied. When the particles are dispersed under the action of ultrasound in this method, uniform dispersion is possible.

20 CGM per 100 weight of binder resin in CGL
-200 parts by weight, preferably 25-100 parts by weight, and CTM is 20-200 parts by weight, preferably 30-15 parts by weight.
0 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 a laminated structure, the film thickness ratio of CGL and CTL is 1:(1~
30) is preferable.

In the case of the single KJtl composition, the charge generating substance is contained in the binder resin in a proportion of 20 to 200 parts by weight, preferably 25 to 100 parts by weight, based on 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 ratio of the charge transport substance to the binder resin is 20 to 2 parts by weight per 100 parts by weight of the binder resin.
00 parts by weight, preferably 30 to 150 parts by weight.

If the content of the charge transport substance 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 weight ratio of the charge transporting material to the charge generating material in the single-layer photosensitive layer is preferably 1:3 to 12.

〔Example〕

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

Example 1 A vinyl chloride-vinyl acetate-maleic anhydride copolymer (S-LEC\IF-IQ,
An intermediate layer having a thickness of 0.1 μm was formed.

Next, polycarbonate resin (Panlite L-1250
, manufactured by Ondai Kasei Co., Ltd.)/'CT M (IX-75)-
1 containing 1% by weight of 100/75 (weight ratio),
A 2-dichloroethane solution was dip coated onto the medium fL'1L to form a 15 μm thick electrical transport layer. Next, C.G.
~■ Sublimated as 1ko4. lO dibrom anthron (■-3) / Panlite L -1250 = 1/2 (
CTM (IX-75) was crushed in a ball mill in 1,2-dichloroethane for 24 hours and dispersed for another 24 hours.
Exemplary compound (6) was added in an amount of 75% by weight relative to -1250 and 05% by weight relative to CTM. A dispersion prepared by adding monochlorobenzene to this solution to give a 1.2-TkU2ruhenzene/monochlorobenzene-7/3 (body Mt ratio) was spray coated onto the CTL, dried, and a charge of 5 μm was obtained. The generation layer was removed to obtain a photoreceptor according to the present invention having a laminated (one-layer) photosensitive layer.

Comparative Example 1 A comparative photoreceptor was obtained in exactly the same manner as in Example 1 except that the exemplified compound (6) was omitted.

Example 2 A photoreceptor was obtained in exactly the same manner as in Example 1 except that Exemplified Compound (7) was used in place of Exemplified Compound (6).

Example 3 A thermosetting acrylic-melamine-epoxy (1:l:1) resin 1. A coating solution in which 55 parts by weight and 0.155 Fm parts of Exemplified Compound (6) were dissolved in a mixed solvent of monochlorobenzene/1.1.2-trichloroethane was spray coated with i'IT L, and dried to a thickness of 1 μm.
A photoreceptor having a thick protective layer was obtained f2.

Example 4 On the photosensitive layer excluding the exemplified compound (6) of Example 1, Brimer PH91 for Nori Convert Coat (manufactured by Toshiba Silicon Corporation) was spray-coated to a thickness of 0.1 μm, and silicone hard was further applied on top of it. Coat Tossguard 510 (manufactured by Toshiba Silicon Corporation) and Exemplary Compound (6) were added to 10 parts by weight per 100 parts by weight of the resin, and the solution was spray applied and dried to form a protective layer of 17 parts by weight and 7 ml. , and obtain one photoreceptor.

Example 5 Vinyl chloride-vinyl acetate-
An intermediate layer having a thickness of about 0.1 μm made of maleic anhydride copolymer (S-LEC MF-10, supra) was formed.

Next, as a coating liquid for CT L, butyral resin (Eslenoku 13X-1. manufactured by Sekisui Chemical Co., Ltd.) 8 weight 1% and CT~I
(IX-75) A coating solution obtained by dissolving 6% by weight in methyl ethyl ketone is applied on the intermediate layer. This was coated and dried to form a charge transport layer with a thickness of 10 μm. Next, CG
i(■-7) 0.29 with paint conditioner (P
aint ConditionerSRed Devi
1,2-dichloroethane/1.1.2-trichloroethane was added to the powder for 30 minutes to give a total concentration of 0.5% by weight. The solution dissolved in 8.39
The polycarbonate resin, CT\=I (IX-75) and exemplified compound (6) were added and dispersed for 3 minutes.
33 weights (4%, 2.6% by weight and 0.26% by weight, respectively)
1.2-dichloroethane/1,1.2 to make heavy %
- Solution 1 obtained by dissolving in trichloroethane mixed solvent
91 g was added and further dispersed for 300 minutes. The thus obtained dispersion was spray-coated onto the CT L and dried to form a charge generation layer with a thickness of 5 μm, thereby obtaining a photoreceptor having a photosensitive layer having a laminated structure.

Comparative Example 2 A comparative photoreceptor was obtained in exactly the same manner as in Example 5 except for the exemplified compound (6) except for the two sides of f.

Example 6 A photoreceptor was obtained in the same manner as in Example 5, except that exemplified compound (7) was used instead of exemplified compound (6).

Example 7 Except for the exemplified compound (6) of Example 5, Nimori Hikari 34
A protective layer containing the same exemplified compound (6) as in Example 3 was placed thereon (same as the photoreceptor of Comparative Example 2) to obtain a photoreceptor.

Example 8 Implementation
A protective layer containing the exemplified compound (6) of η was provided as in Example ① to obtain a photoreceptor.

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

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

Attach the photoreceptor at 90 pptq between the ozone layers, ↓6
The photosensitive layer is charged by corona discharge for 5 seconds by applying the electrical voltage (■) to the surface.The photosensitive layer is then left for 5 seconds (the potential at this time is set as the initial potential V0), and then exposed to light until the illumination intensity on the surface is 14. Light from a tungsten lamp in a state of lux, 11
One shot was fired, and this operation was repeated 100 times.

When the potential after 100 irradiations is ■1, v, /vox1
00 (%) represents ozone resistance. V, /V, is 10
This shows the degree of potential drop after 0 repetitions, and the larger the value, the more childish it is.

It can be seen from the attached table that all of the photoreceptors of the present invention have excellent ozone resistance, whereas the comparison photoreceptor suffers from more ozone deterioration.

[Brief explanation of drawings]

1 to 3 are cross-sectional views of photomaterials for use in the present invention: 1.Support 2.Charge transport layer 3.Charge generation layer 4.Photosensitive layer 5. ...Charge transport material (C'rM) 6...Charge generating material (CGM) 7..Protective layer

Claims (1)

[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▲ Numerical formula, chemical formula, table, etc.▼ [In the formula, R represents a hydrogen atom, an alkyl group, an aryl group, or an aralkyl group, and R' represents an alkyl group. ]