JPS62157047A - Photosensitive body for positive charge - Google Patents

Abstract

PURPOSE:To obtain the titled body having an improved printing resistance by providing a protective layer contg. an electron acceptor as a substance capable of contributing to transferring an electrostatic charge carrier, and by incorporating a resin curable by a light or a heat to a binder of the protective layer as a main component, thereby controlling a harmful outside action of influences of a light radiation, a corona discharge and a humidity, etc., and especially a mechanical abrasion and a damage. CONSTITUTION:The protective layer contg. the electron acceptor is formed on the photosensitive layer composed of a monolayer or a laminated layer. As the electron acceptor usable to the protective layer of the photosensitive body, one may use citric anhydride, maleic anhydride, dibromomaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, etc. As the electron acceptor, especially, the compd. having an electron affinity EA of 0.3eV<=EA<=1.8eV. is preferably used. The amount of the electron acceptor contg. in the protective layer is 0.1-50wt%, preferably 1-50wt%.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in positively charging photoreceptors.

[Conventional technology]

Conventionally, photoreceptors having a photosensitive layer containing an inorganic leading conductive substance such as selenium, zinc oxide, or cadmium sulfide have been widely used as photoreceptors for electrophotography, for example.

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
-hinylcarhazole and 2.4.7, -trinitro-9
- An organic photoreceptor having a photosensitive layer containing fluorenone is described. However, this photoreceptor is not necessarily satisfactory in terms of sensitivity and durability. In order to improve such drawbacks, in the photosensitive layer, the carrier generation function and the carrier transporting function are individually assigned to the substance 5+a.1. Attempts have been made to develop organic photoreceptors with high sensitivity and great durability.

In such so-called function-separated type electrophotographic photoreceptors, materials that exhibit each function can be selected from a wide range of materials, so it is possible to create an electrophotographic photoreceptor with arbitrary characteristics. It can be easily manufactured.

Many substances have been proposed as carrier-generating substances that are effective for such functionally separated electrophotographic photoreceptors.

Examples of using inorganic substances include, for example, Japanese Patent Publication No. 43-16
As described in Publication No. 1'J8, there is amorphous selenium, which can be combined with an organic carrier-generating substance.

In addition, many electrophotographic photoreceptors using organic dyes or organic pigments as carrier-generating substances have been proposed. Publication No. 55-22834, Japanese Patent Application Laid-open No. 79632-1982, Japanese Patent Application Publication No. 1987-11
This is already known from Publication No. 6040 and the like.

By the way, conventional photoreceptors using organic photoconductive materials are generally used for negative band applications.

The reason for this is that when negatively charged, the mobility of holes among carriers is high, 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. Still another problem is that positive polarity toner is required for development of a negatively charged photoreceptor, but positive polarity toner is difficult to manufacture in view of the triboelectrification series with respect to ferromagnetic carrier 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 carrier transport layer on a carrier generation layer, a material with a large electron transport ability, such as trinitrofluorenone, is added to the carrier transport layer 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 states that thiapyrylium salt (derived from a carrier (1-
B is shown in which a substance) is contained in a polycarbonate (binder resin) so as to form an 11-crystal complex.

However, with this known photoreceptor, there is a large memory phenomenon.
It has the disadvantage that ghosts are likely to occur. U.S. Pat. No. 3,357,989 also discloses a photoreceptor containing phthalonoanine, but the characteristics of phthalonoanine vary depending on the crystal form, and the crystal form must be strictly controlled, which may be a problem. In addition, it has a large memory phenomenon and low short wavelength sensitivity, making it unsuitable for copying machines whose light source is visible light including the short wavelength.

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.

[Problem that the invention seeks to solve]

Therefore, the photosensitive layer has a laminated structure in which the upper layer (surface layer) is a carrier generation layer containing a carrier generation substance that generates holes and electrons when irradiated with light, and the lower layer is a carrier transport layer containing a carrier transport substance having a hole transport function. It is conceivable to use the photoreceptor for positive charging. Furthermore, it is considered that a photoreceptor having a single-layer photosensitive layer containing the carrier-generating substance and the carrier-transporting substance can also be used for positive charging. In addition, in such a photoreceptor that is used for positive charging, if a carrier generating substance having, for example, an electron-withdrawing group is used in the structure, the movement of electrons to cancel the positive charge on the surface of the photoreceptor will be accelerated. , it is thought that high sensitivity characteristics can be obtained.

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

In a negative charging photoreceptor having a conventional carrier transport layer as a surface layer, the effects of the various parts mentioned above are extremely small.
Rather, the carrier transport layer has the function of protecting the underlying carrier generation layer.

On the other hand, in the case of a positively charging photoreceptor, the surface layer containing a carrier-generating substance is subject to mechanical abrasion and damage due to external effects, especially development and cleaning, resulting in white spots and
Image defects such as white streaks and other deterioration of electrophotographic performance such as surface potential, sensitivity, memory, and residual potential 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 carrier-generating substance, but the carriers generated during light irradiation are blocked by the protective layer and lead to conductivity. There is a problem that we should lose this.

[Means for solving problems]

(Objective of the Invention) The object of the present invention is to provide a protective layer on the surface layer of the photoreceptor that does not affect the photographic characteristics inherent to the photoreceptor, thereby preventing the effects of light irradiation, corona discharge, humidity, etc. In particular, the object is to suppress harmful external effects such as mechanical wear and damage, and to improve the printing durability of the positively charging photoreceptor.

(Structure of the Invention) The above-mentioned object has a protective layer containing an electron-accepting substance as a substance contributing to the transport of charge carriers, and the binder of the protective layer is mainly composed of a resin that hardens with light or heat. This is achieved using a positive charging photoreceptor.

In the photoreceptor of the present invention, a single-layer photosensitive layer containing a carrier-generating substance, a carrier-transporting substance, and optionally a binder resin, or a carrier-transporting layer containing a carrier-transporting substance and optionally a binder resin as the lower layer, A protective layer containing an electron-accepting substance is formed on a photosensitive layer with a laminated structure in which a carrier-generating substance is formed on a carrier-transporting layer and, if necessary, a carrier-generating layer containing a carrier-transporting substance and a binder resin is formed as an upper layer (surface layer). Moreover, by using a thermosetting resin as the binder of the protective layer, the mechanical strength of the photoreceptor surface is improved and the rigidity resistance is increased.

In the photoreceptor configured as described above, when the layer containing the carrier-generating substance is irradiated with light and holes and electrons are generated, the holes quickly move to the substrate side via the carrier transport layer, and the electrons are Promoted by the electron-accepting substance present in the protective layer and having a function of contributing to electron transport, it moves rapidly through the protective layer and cancels out the positive charges on the surface. In this way, even a photoreceptor coated with a protective layer exhibits high sensitivity characteristics.

Examples of electron-accepting substances used in the protective layer of the photoreceptor of the present invention include succinic anhydride, maleic anhydride, dibromaleic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromophthalic anhydride, 3-nitro Phthalic anhydride, 4-nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetraanoquinodimethane, 0-dinitrobenzene, m-dinitrobenzene, 1.3,5. -1-dinitrobenzene, paranitrobenzonitrile, vicryl chloride, quinone chlorimide, chloranil, brumanil, 2-methylnaphthoquinone, dichlorodine anovabenzoquinone, anthraquinone, dinitroanthraquinone, trinitrofluorenone, 9-fluorenonedene [dicyanomethylene malonone nitrile], polynitro-9-fluorenonedene [ginanomethylenemalonodinitrile], picric acid,
Examples thereof include 0-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, pentafluorobenzoic acid, folic acid, 5-nitrosalicylic acid, 3,5-')nitrosalicylic acid, and phthalic acid.

However, the electron-accepting substance has a particularly high electron affinity E
A is preferably in the range of 0.3 eV≦EA≦1.8 eV, and when the electron affinity EA is less than 0.3 eV, photosensitivity decreases; ．． If it exceeds 8eV, it will become charged.
In addition, the amount of the electron-accepting substance contained in the protective layer is 01 to 50% by weight, preferably 1 to 50% by weight, and 0.1% by weight. If it is less than 50% by weight, the photosensitivity will be poor, and if it exceeds 50% by weight, the solvent solubility will be poor.

Next, +i77:' + Protection containing a self-receptive substance, Hibiki is a binder, and - (I2 bond resistance 108 Ω cm or more, preferably: 101') Ω 0 m or more, more preferably 1 o 13 Ω A transparent binder with a length of 0 m or more is used.The binder is said to contain at least 50% by weight of a resin that is cured by light or heat.

Examples of such resins that harden with light or heat include thermosetting acrylic resins, flexible resins, epoxy resins, urethane resins, urea resins, phenol resins, polyester 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, the protective layer may contain less than 50% by weight of a thermoplastic resin for the purpose of improving processability 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, Evoquin resin, butyral resin, polycarbonate resin, Fricon resin, or copolymer resins thereof, such as vinyl chloride-vinyl acetate copolymer resin. Polymer resins, hinyl chloride-hinyl acetate-maleino acid anhydride copolymer resins, polymeric organic semiconductors such as poly-N-vinylcarbazole, and other thermoplastic resins used in electrophotographic materials can all be used.

In addition to the electron-accepting substance, the protective layer may contain an ultraviolet absorber or the like for the purpose of protecting the carrier generation properties, if necessary, and is dissolved in a solvent together with the binder, for example, by dip coating, spray coating, blade coating, etc. It is applied and dried by coating, roll coating, etc. to a thickness of 2 μm or less, preferably 1 μm.
It is formed to a layer thickness of μm or less.

Note that the film thickness after drying is a thin film that is less than the polygon constant variation, and a reinforcing effect equivalent to +'l is exhibited just by fixing the particles of the carrier-generating substance.

Incidentally, the resistance of the binder in the above protective layer is measured by the following method.

The sample was placed in a measurement cell with a cross section fa I cm2 (F am') to a depth of 0.03 to 0.08 cm (h cm),
Apply If (IKg) from the top surface and measure the current value (1 ampere) when the applied voltage (V port) is changed,
It is calculated by the following formula and refers to f2.

Next, as a carrier-generating substance suitable for the present invention, since it absorbs 1 visible radiation and generates free carriers, 15! lHB Can you use organic pigments or organic pigments? 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, stilhen azo and deazole 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 isoviolanthrone derivatives (4) Indigoid pigments such as ingo derivatives and dioindigo derivatives (5) Phthalocyanine group Mtl such as metal phthalocyanine 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, oxazine pigments and thiazine pigments (8) Methine pigments such as noanine pigments and azomethine pigments (9) ) Gynolino pigments (10) Nitro pigments (11) Nitroso pigments (12) Henzoquinone and naphthoginone pigments (13)
Naphthalimide pigments (14) Perinone pigments such as bishenzimidazole derivatives, but preferably azo or polycyclic quinone pigments with electron-withdrawing properties, with an average particle diameter of 2 μm or less, especially 171 m
The following granules are preferably dispersed and contained in the photosensitive layer.

In this case, the electrophotographic properties of the photoreceptor, such as photosensitivity, memory phenomenon, residual m-position, etc., become better.

In addition, when the azo pigment alone is negatively charged on the surface of the photosensitive layer, the electron transfer rate in the layer is two times higher than when it is positively charged (that is, the photosensitivity when negatively charged is high).
The electrons generated during light irradiation can quickly cancel the positive charge on the surface of the photosensitive layer and exhibit high photosensitivity.

In other words, when used in the surface layer of a positive charging photoreceptor, it has extremely high photosensitivity.

Examples of azo pigments suitable for the present invention include the following exemplified compound groups [:l:] to [].

bottom margin Exemplary compound group [I]: Exemplary compound group (II) Exemplary compound group [■].

Exemplified compounds [■] and the following exemplified compounds (CVT) as gearia-generating substances
Polycyclic quinone pigments represented by ~[■] are used.

Exemplary compound group [■]: Exemplary compound group [■]: Exemplary compound group [■]: Next, there are no particular restrictions on carrier transport substances that can be used in the present invention, but for example, oxazole derivatives, oxadiazole derivatives, Thiazole derivatives, deadiazole derivatives, triazole derivatives, imidazole derivatives, imidasilone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, pyrazoline derivatives, oxacilone derivatives, hendithiazole derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, They may be acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, and the like.

However, in addition to being excellent in the ability to transport holes generated during light irradiation to the support side, those suitable for combination with the carrier-generating substance are preferably used, and such carrier-transporting substances include, for example, the following exemplified compound group (IX ) or (X) ++ri nok /to sawa-h<
7 cities 1) Exemplary compound group (IX): Exemplary compound group (X) Also, the following exemplary compound group (XI) ~ as a carrier transport substance
Hydrazone compounds represented by (XV) can be used.

Exemplified Compound Group [■] Exemplified Compound Group (X1ll): Exemplified Compound Group [X■): Pyrazoline compounds represented by the following exemplary compound (XVT) can also be used as carrier transport substances.

In addition, as carrier transport substances, the following exemplified compound group - [X■]
Amine derivatives represented by can also be used.

As described above, the photoreceptor of the present invention has a single-layer photosensitive layer on a support containing a carrier-generating substance, a carrier-transporting substance, and optionally a binder resin, or a photosensitive layer containing a carrier-generating substance and optionally a carrier-transporting substance and a binder resin. A photosensitive layer is provided in a laminated structure in which the upper layer is a carrier generation layer containing a carrier transport material, a carrier transport layer containing a carrier transport substance and optionally a binder resin is provided as a lower layer, and a protective layer is further provided on top of the photosensitive layer.

Binder resins that can be used in such photoreceptors include, for example, polystyrene, polyethylene, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, Epoquin resin,
Addition polymerization resins such as polyurethane resins, phenolic resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, polyaddition resins,
Polycondensation resins and copolymer resins containing two or more repeating units of these resins, such as vinyl chloride-
In addition to insulating resins such as vinyl acetate copolymer resin, pinychloride-vinyl acetate-maleic anhydride copolymer resin, poly-
Examples include polymeric organic semiconductors such as N-vinylcarbazole.

Further, in the photoreceptor of the present invention, organic amines can be added to the photosensitive layer for the purpose of improving the carrier generation function of the carrier generation substance, and it is particularly preferable to add a 2-handling amine.

Examples of such amines include dimethylamine, noethylamine, non-propylamine, di-isopropylamine, di-n-butylamine, di-isobutylamine, di-n-amylamine, di-isoamylamine, di-n-
Hexylamine, di-isohexylamine, di-n pentylamine, di-isopentylamine, di-n octylamine, no-isooctylamine, di-n nonylamine, di-isononylamine, di-n decylamine, di-n
Examples include amylamine, di-n monodecylamine, di-isomonodecylamine, di-n dodecylamine, and neutral decylamine.

The amount of the secondary amine to be added is preferably 1 times or less, preferably 0.2 to 0.005 times the amount of the carrier-generating substance relative to the key carrier-generating substance.

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.

When the photoreceptor of the present invention has a single layer structure, the ratio of the carrier generating substance contained in the binder resin is 100% of the binder resin.
20 to 200 parts by weight, preferably 25 to 200 parts by weight
The amount is 100 parts by weight.

If the content of the carrier-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 carrier 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 carrier 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 carrier transporting substance to the carrier generating substance in the single-layer photosensitive layer is preferably from 1:3 to 1:2.

The layer structure of the photosensitive layer of the photoreceptor of the present invention has a single layer structure and a laminated structure as described above. Since the carrier-generating substance has a property of promoting properties, it is possible to increase the grip of the carrier-generating substance on the binder resin in the layer containing the carrier-generating substance more than before. Therefore, the range of improvement in electrophotographic properties such as sensitivity, memory, residual potential, etc. of the photoreceptor is expanded accordingly.

Next, in the case of the above-mentioned laminated structure, the carrier-generating material is 20 to 20% per 100 parts by weight of the binder resin in the carrier-generating layer.
0 parts by weight, preferably 25 to 100 parts by weight, and the carrier transport material is 20 to 200 parts by weight, preferably 30 parts by weight.
~150 parts by weight. If the amount of the carrier 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 will increase and the acceptance potential will decrease.

Furthermore, if the amount of the carrier transport substance is less than this, the photosensitivity will decrease and the residual potential will increase, and if it is more than this, the solvent solubility will deteriorate.

Next, in the case of the laminated structure, the carrier transporting material is 20 to 200 parts per 100 parts by weight of the binder resin in the carrier transporting layer.
parts by weight, preferably from 30 to 150 parts by weight.

If the content of the carrier 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 positive charging photoreceptor of the present invention is constructed as shown in FIGS. 1 to 3, for example.

FIG. 1 shows a photosensitive layer 4 having a thickness of 2 μm to 20 μm, in which a granular carrier-generating material 6 made of the azo pigment is dispersed in a layer containing the carrier transporting material 7a and a binder resin, on a conductive support 1. A structure is shown in which a protective layer 8 containing an electron-accepting substance is provided directly or via an intermediate layer (not shown) on the protective layer 8.

Further, FIG. 2 shows a carrier transport layer 3 containing a carrier transport substance 7b and a binder resin with a thickness of 5 μm to 50 μm, and a film with a thickness of 0.05 μm in which the granular carrier generating substance 6 is dispersed in the layer containing the binder resin. A structure is shown in which a photosensitive layer 4 having a laminated structure consisting of a carrier generation layer 2 of ~10 μm is provided on a conductive support, and a protective layer 8 containing an electron-accepting substance is further provided thereon.

FIG. 3 shows that the carrier-transporting substance 7a is also contained in the carrier-generating layer 2 of FIG. The filter point is different from the layer structure shown in FIG.

Here, as a method for manufacturing such a photoreceptor, for example, the carrier generating substance 6 is dispersed in the form of fine particles of 0.01 to 1.0 μm in a dispersion medium, and the binder resin and the carrier transporting substance 7a are dispersed.
A coating solution is prepared by mixing and dispersing, for example, by ultrasonic dispersion, and is coated on a conductive support via an intermediate layer 5 if necessary by a coating method such as dip, spray, blade, or roll, and then dried. A photosensitive layer 4 is obtained, and a protective layer 8 is formed by applying a thin layer of a solution containing an electron-accepting substance and a binder resin thereon and drying it to form a photosensitive layer 8 having a single layer structure as shown in FIG. A photoreceptor having the following characteristics is obtained.

Also, for example, a binder resin and a carrier transport substance 7 may be present in a solvent.
Form a carrier transport layer by coating and drying a solution in which b is dissolved on a conductive support via an intermediate layer 5 if necessary,
For example, the photosensitive layer 4 shown in FIG. 1 is provided thereon as the carrier generation layer 2, and a protective layer 8 similar to that shown in FIG. be made to obtain.

Examples of the solvent used to form each layer include N,
N-dimethylformamide, benzene, toluene, xylene, monochlorobenzene, l.

Examples include 2-dichloroethane, dichloromethane, 1,1,2-trichloroethane, tetrahydrofuran, methyl ethyl ketone, ethyl acetate, and butyl acetate.

The intermediate layer 5 functions as an adhesive layer or a barrier layer, and includes, in addition to the binder resin, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate, etc. Maleic anhydride copolymer, casein, starch, etc. are used.

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

[Example l]

On a conductive support made of polyester laminated with aluminum foil, a layer of approximately 0.05 μm thick made of vinyl chloride-vinyl acetate-maleic anhydride copolymer ("S-LEC MF-10" manufactured by Tsukisui Kagaku Kogyo Co., Ltd.) was placed on a conductive support made of polyester laminated with aluminum foil. An intermediate layer was formed. Next, 30 parts by weight of the bisazo carrier generating substance shown in Compound Example (IV, -7) and Compound Example (IX
-43) 75 parts by weight of the carrier transporting substance and 100 parts by weight of binder resin polycarbonate (Panlite-1250J manufactured by Teijin Kasei Co., Ltd.) were mixed with amine in an amount of 0.02 mol per 1 mol of the carrier-generating substance. Contains 1
, into 150 parts by weight of a 2-di-chloroethane/di-isobutylamine mixed solvent, and mixed and dispersed in a ball mill for 12 hours.

The obtained dispersion was applied onto the intermediate layer and dried to form a layer of 12 μm.
A thick single-layer photosensitive layer was obtained. Next, 0.42 zine-anodichlorobenzene was applied as an electron-accepting substance on this photosensitive layer.
Spray coating method using a coating solution obtained by dissolving 0.80 parts by weight of a thermosetting polyester resin as a binder resin and 0.8 parts by weight of the polycarbonate resin in 100 parts by weight of a solvent 1,2-dichloroethane. A thin layer was coated and dried to form a protective layer with a thickness of 1 μm, thereby obtaining a photoreceptor of the present invention.

(Examples 2 to 15) Example 1 was prepared in the same manner as in Example 1, except that the electron-accepting substance in the protective layer and the type of thermosetting resin in the binder were changed as shown in the attached table.
Five types of photoreceptors of the present invention were obtained.

(Comparative Examples 1 to 4) Comparative Examples 1 to 4 were carried out in the same manner as in Example 1, except that the protective layer was removed or the type of thermosetting resin in the binder of the protective layer was changed as shown in the attached table, and the electron-accepting substance was removed. Comparative photoreceptors of different types were obtained.

(Example +6) Vinyl chloride-vinyl acetate-maleic anhydride copolymer “S-LEC M
P'-10J (manufactured by Tsukisui Kagaku Kogyo Co., Ltd.) with a thickness of 0
．． An intermediate layer of 0.05 μm was provided.

Next, 50 parts by weight of the polycyclic quinone carrier generating substance shown in Compound Example (VI-4) and Compound Example (IX-7) were added.
5) 75 parts by weight of the carrier transport substance and polycarbonate ("Panlite L-1250") as a binder resin.
110 parts by weight (manufactured by Teijin Kasei Co., Ltd.) were added to 2500 parts by weight of a mixed solvent of dichloromethane/trichloroethane, and mixed and dispersed in a ball mill for 12 hours.

The obtained dispersion was coated on the intermediate layer, dried, and coated with 13μ
A photosensitive layer having a single layer structure and having a thickness of m was obtained. Next, on this photosensitive layer, 0.46 parts by weight of chloranil shown in the attached table as an electron-accepting substance and 160 parts by weight of a thermosetting polyester resin were added to the solvent monochlorobenzene/1,1,2-trichloroethane 10 parts by weight.
A coating solution obtained by dissolving the coating solution in 0 parts by weight was applied to a thin layer by a spray coating method and dried to form a protective layer with a thickness of 1 μm, thereby obtaining a photoreceptor of the present invention.

(Examples 17 to 21) Five types of photoreceptors of the present invention were obtained in the same manner as in Example 16, except that the binder resin (thermosetting resin) and the type of electron-accepting substance in the protective layer were changed as shown in the attached table. Ta.

(Comparative Example 5) A comparative photoreceptor was obtained in the same manner as in Example 16 except that the protective layer was removed.

The photoreceptor thus obtained was mounted on an electrostatic tester rSP-428 model (manufactured by Kawaguchi Denki Seisaku Shin), and the following characteristic tests were conducted. That is, a voltage of +6 KV is applied to the charger to charge the photosensitive layer by corona discharge for 5 seconds, and then the photosensitive layer is left for 5 seconds (the potential at this time is called the initial potential), and then the illuminance on the surface of the photosensitive layer is 14 lux ( Examples 1 to 15 and Comparative Examples 1 to 4) or 35 Lux (Examples 16 to 2)
1 and Comparative Example 5), irradiate light from a tungsten lamp and increase the initial potential from +600 volts to +
Exposure required to attenuate to 100 volts @ , E 0
0G (lux seconds) was measured.

In addition, residual 'QI
FLVr, volts were measured. Furthermore, the residual potential Vrs was also measured when the above steps were repeated five times (however, the residual potential was erased at the end of each of the first to fourth steps). Furthermore, the mechanical strength of each photoreceptor surface was measured using a modified U-Bix2500M R (manufactured by Konishiroku Photo Industry Co., Ltd.) under the following conditions, and the obtained results were marked as "○" or "x".
It was evaluated using the following method. The above measurement results are shown in the attached table.

The conditions for measuring mechanical strength are as follows.

After developing with a reverse bias using a modified U-Bix 25QOM R machine, a PE blade (Luminar manufactured by Toshisha Co., Ltd.) was used to continuously develop the image using a load of 1 (1 (Igf/cm) for 10. (10
The photoreceptors of the present invention are all excellent in both electrophotographic properties and mechanical strength, whereas the comparative photoreceptors have excellent electrophotographic properties and mechanical strength. It can be seen that the body has drawbacks such as excessive residual potential and weak mechanical strength.

(Example 22) Vinyl chloride-vinyl acetate-
Maleic anhydride copolymer “S-LEC M P-10J
(manufactured by Tsukisui Kagaku Co., Ltd.) with a thickness of about 0.005 μm was formed. Next, 99 parts by weight of the carrier transport substance shown in the above compound example (IX-54) and a binder resin polycarbonate (“Panlite-1250” manufactured by Kijin Kasei Co., Ltd.) were added.
The most part of the 13.2 layer was added to 1,500 parts of 1,2-dichloroethane, mixed and dissolved in a ball mill for 12 hours, and the resulting solution was applied onto the intermediate layer and dried to obtain a carrier transport layer with a thickness of 13 μm.

Next, the above-mentioned exemplified compound (■-7) was extracted from the xylem triphosphate: 13.0; 0.Nimi'7';
lj:, 1 75 parts by weight of the carrier transporting substance shown above, 100 parts by weight of the polycarbonate binder resin, and 0.02 mol of di-isobutylamine per 1 mol of the carrier generating substance are added to 1,500 parts by weight of 1,2-dichloroethane. A dispersion obtained by dispersing in a ball mill for 12 hours was applied onto the carrier transport layer and dried, and a carrier generation layer having a thickness of 5 μm was laminated to form a photosensitive layer having a laminated structure.

Next, 0.32 parts by weight of 2-methylnaphthoquinone was added as an electron-accepting substance on the photosensitive layer, and a thermosetting acrylic-melamine-evoquino resin ("Dyanal HR-116J" manufactured by Mitsubishi Rayon Co., Ltd., "Super") was added as a binder resin. A solution prepared by dissolving 1.60 parts by weight (solid content) of Beckamine J-820j (manufactured by Dainippon Ink Co., Ltd.) in 100 parts by weight in a solvent kiln was applied by a spray coating method and dried to form a protective layer with a thickness of 0.05 μm. A photoreceptor of the present invention was obtained.

Using this photoreceptor, the electrophotographic performance and mechanical strength were measured by the /II++ standard method as in Example 1.
=; 1st j, Ni Mito, E Yu
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〔Effect of the invention〕

As is clear from the above description, according to the photoreceptor of the present invention,
The mechanical strength of the photoreceptor surface is high, it is highly durable, has high sensitivity characteristics for positive charging, and has excellent residual potential and other electrophotographic performance. Ru.

[Brief explanation of drawings]

FIGS. 1 to 3 show the face of a photoreceptor for positive charging according to the present invention. 1...Support 2.・Carrier generation layer 3,
...Carrier transport layer 4 ...Photosensitive layer 5 ...Intermediate layer 6, ...Carrier generating substance 7 ...Carrier transport substance 8, ...Protective layer Applicant: Roku Konishi Photo Industry Co., Ltd. Figure 1

Claims (7)

[Claims] (1) Positively charged, characterized in that it has a protective layer containing an electron-accepting substance as a substance that contributes to the transport of charge carriers, and the binder of the protective layer is mainly composed of a resin that hardens with light or heat. Photoreceptor for use. (2) The electron affinity EA of the electron-accepting substance is 0.3e
Claim 1 in the range of V≦EA≦1.8eV
Positive charging photoreceptor as described in . (3) The electron-accepting substance is present in the protective layer at 0.1 to 5
The positive charging photoreceptor according to claim 1, which contains 0% by weight. (4) The positively charging photoreceptor according to claim 1, wherein the protective layer is provided on a photosensitive layer containing a carrier-generating substance and a carrier-transporting substance. (5) The photoreceptor for positive charging according to claim 4, wherein the carrier generating substance comprises an azo pigment or a polycyclic quinone pigment. (6) The photoreceptor for positive charging according to claim 4 or 5, wherein the carrier generating substance comprises an azo pigment or a polycyclic quinone pigment having an electron-withdrawing group. (7) The photoreceptor for positive charging according to claim 4, wherein the carrier transport substance is a styryl compound, a hydrazone compound, a pyrazoline compound, or an amine derivative as described in the main text.