JP2009069654A - Electrophotographic photoreceptor containing diamine compound and image forming apparatus with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor in which a novel diamine compound having an excellent ozone resistant property, usable for providing an electrophotographic photoreceptor without harm to the other characteristics, is added to the surface protection layer. <P>SOLUTION: On a conductive support made of a conductive material the electrophotographic photoreceptor comprises a single layer photosensitive layer containing a charge generating substance and a charge transporting substance, or a lamination type photosensitive layer having a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance laminated in this order, and a surface protection layer laminated in this order. The surface protection layer contains a specific diamine compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrophotographic photoreceptor containing a diamine compound and an image forming apparatus including the same.

2. Description of the Related Art An electrophotographic image forming apparatus (hereinafter also referred to as “electrophotographic apparatus”) that forms an image using electrophotographic technology is widely used in copying machines, printers, facsimile apparatuses, and the like.
In an electrophotographic apparatus, an image is formed through the following electrophotographic process. First, a photosensitive layer of an electrophotographic photosensitive member (hereinafter also referred to as “photosensitive member”) provided in the apparatus is charged and then exposed to form an electrostatic latent image. The formed electrostatic latent image is developed to form a toner image, and the formed toner image is transferred onto a transfer material such as recording paper and fixed to form a desired image on the transfer material.

  In recent years, electrophotographic technology has been used not only in the field of copying machines but also in the fields of printing plate materials, slide films, microfilms, and the like in which silver salt photographic technology has been conventionally used. For example, it is also applied to a high-speed printer using a laser, a light emitting diode (abbreviated as LED), a cathode ray tube (abbreviated as CRT), or the like as a light source. With the expansion of the application range of electrophotographic technology, the demand for photoreceptors is becoming advanced and wide.

Conventionally, inorganic photoreceptors having a photosensitive layer mainly composed of an inorganic photoconductive material such as selenium, zinc oxide or cadmium sulfide have been widely used as the photoreceptor.
Inorganic photoconductors have some basic characteristics as photoconductors, but have disadvantages such as difficulty in forming a photosensitive layer, poor plasticity, and high production costs. In addition, inorganic photoconductive materials are generally highly toxic and have significant limitations in manufacturing and handling.
As described above, since the inorganic photoconductive material and the inorganic photoreceptor using the inorganic photoconductive material have many drawbacks, research and development of the organic photoconductive material has been advanced.

In recent years, organic photoconductive materials have been widely researched and developed, and are not only used for electrostatic recording elements such as photoreceptors, but also have begun to be applied to sensor elements, organic electroluminescent (EL) elements, and the like. Yes.
Organic photoconductors using organic photoconductive materials have good film-forming properties, excellent flexibility, light weight, good transparency, and a wide wavelength range by appropriate sensitization methods. However, it has been gradually developed as the main force of the photoconductor because it has an advantage that a photoconductor showing good sensitivity can be easily designed.

  However, the organic photoreceptor has a large film thickness of the photosensitive layer due to repeated use, and as it progresses, the charged potential of the photoreceptor decreases, the photosensitivity deteriorates, the background becomes dirty due to scratches on the surface of the photoreceptor, the image density decreases, or There is a strong tendency for image quality degradation to be accelerated. Therefore, the wear resistance of organic photoreceptors has been cited as a major problem. Further, in recent years, with the increase in the speed of an electrophotographic apparatus or the reduction in the diameter of the photoreceptor accompanying the downsizing of the apparatus, it has become a more important issue to improve the durability of the photoreceptor.

As a method for realizing high durability of the photoconductor, a method of providing a surface protective layer on the outermost surface of the photoconductor has been widely known.
However, when the surface protective layer has high electrophotographic resistance (10 ¹⁴ Ω · cm or more), there are problems such as an increase in residual potential and accumulation during repeated use, which is not preferable in practice.

Therefore, as a technique for compensating for such drawbacks, a method of using a surface protective layer as a photoconductive layer, a method of adding a transfer agent typified by a dye or a Lewis acid in the surface protective layer, and a method of adding metal or metal oxide fine particles A method for controlling the resistance of the surface protective layer by addition is proposed.
By these methods, it is possible to reduce the resistance of the surface protective layer and suppress an increase in the residual potential when the electrophotographic photosensitive member is repeatedly used.
However, in such a case, there arises a problem that the outline of the image is blurred, so-called image blur occurs.

In addition, an oxidizing gas such as ozone or nitrogen oxide derived from the image forming process permeates the surface protective layer to chemically change the charge transport material of the photosensitive layer, resulting in various characteristic changes. When the surface protective layer contains the above-mentioned additives, there is a problem that the image blurring problem becomes more prominent because they may interact with each other before reaching the photosensitive layer.
As a method for solving this problem, a method of adding an antioxidant into the protective layer is widely known.

  For example, JP-A-62-105151 (Patent Document 1) discloses that an antioxidant having a triazine ring and a hindered phenol skeleton in the molecule is added to the photosensitive layer, and JP-A-63-18355 ( Patent Document 2) discloses that a specific hindered amine is added to the photosensitive layer. JP-A 63-4238 (Patent Document 3), JP-A 63-216055 (Patent Document 4) and JP-A-3-172852 (Patent Document 5) disclose trialkylamines, aromatics. Japanese Patent Application Laid-Open No. 5-158258 (Patent Document 6) discloses adding an amine dimer to a photosensitive layer. However, these are still not sufficient. .

JP 62-105151 A JP-A-63-18355 Japanese Unexamined Patent Publication No. 63-4238 Japanese Patent Laid-Open No. 63-216055 JP-A-3-172852 JP-A-5-158258

  That is, sufficient ozone resistance has not yet been achieved by such conventional techniques, and addition of such an antioxidant deteriorates electrophotographic characteristics such as sensitivity and residual potential. However, the current situation is that there are still problems that are insufficient for practical use. Therefore, a new material proposal that improves ozone resistance and has no harmful effect on electrophotographic characteristics is awaited.

  Therefore, the present invention provides a photoconductor in which a novel diamine compound is added to the surface protective layer and can be used to provide a photoconductor excellent in the effect of ozone resistance and having no adverse effects on other characteristics. It is an object of the present invention to provide an image forming apparatus provided.

  As a result of intensive research, the present inventors can obtain a photoconductor excellent in ozone resistance and having no adverse effects on electrophotographic characteristics by adding a specific diamine compound to the surface protective layer. As a result, the present invention has been completed.

Thus, according to the present invention, on a conductive support made of a conductive material, a single-layer photosensitive layer containing a charge generating substance and a charge transporting substance or a charge generating layer containing a charge generating substance and a charge transporting substance A charge-transporting layer containing a laminate type photosensitive layer laminated in this order and a surface protective layer laminated in this order, wherein the surface protective layer comprises:
General formula (1):

(In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ are the same or different, and an aryl group which may have a substituent or a cycloalkyl group which may have a substituent) , A heteroatom-containing cycloalkyl group which may have a substituent or a monovalent heterocyclic residue which may have a substituent; Y ¹ , Y ² , Y ³ and Y ⁴ may be the same or different A chain-like alkylene group which may have a substituent)
A photoconductor comprising a diamine compound represented by the formula: is provided.
The numbering of the substituents in the chemical formulas described in the present specification includes upper left, upper right, and lower right letters, but these are the same. For example, “ ¹ Ar” and “Ar ¹ ” represent the same substituent.

  According to the present invention, the above-mentioned photoconductor, a charging unit for charging the photoconductor, an exposure unit for exposing the charged photoconductor, and an electrostatic latent image formed by the exposure are provided. An image forming apparatus including a developing unit for developing is provided.

By including the diamine compound of the present invention in the surface protective layer, it is possible to provide a photoreceptor excellent in ozone resistance effect and at the same time excellent in durability and environmental stability.
Further, even when the photoreceptor of the present invention is used in a high-speed electrophotographic process, it can provide a high-quality image due to its excellent ozone resistance effect.
Therefore, by using the photoconductor according to the present invention, it is possible to form a high-quality image excellent in ozone resistance even when used repeatedly for a long period of time.

Further, since the photoreceptor according to the present invention contains the diamine compound according to the present invention in the photosensitive layer, it is excellent in the effect of ozone resistance and is excellent in terms of a photoreceptor resting memory phenomenon associated with a longer life of the photoreceptor.
Therefore, the image forming apparatus according to the present invention can stably form a high-quality image free from image defects over a long period of time under various environments.
Further, since the photoconductor according to the present invention can provide a high-quality image even in a high-speed electrophotographic process, the image forming apparatus according to the present invention can increase the image forming speed.

  The photoreceptor of the present invention comprises a single layer type photosensitive layer containing a charge generating substance and a charge transporting substance or a charge generating layer containing a charge generating substance and a charge transporting substance on a conductive support made of a conductive material. A photosensitive member in which a layered photosensitive layer having a charge transport layer contained therein is laminated in this order and a surface protective layer are laminated in this order, and the surface protective layer is represented by the general formula (1). It contains a diamine compound.

Among such diamine compounds of the general formula (1), points such as chemical stability against decomposition or alteration as a chemical substance, easy availability of raw materials, ease of production and high yield, and production cost A diamine compound in which Y ¹ , Y ² , Y ³ and Y ⁴ in the general formula (1) are chain alkylene groups, that is, the sub-formula (2):

（式中、Ａｒ¹、Ａｒ²、Ａｒ³、Ａｒ⁴、Ａｒ⁵およびＡｒ⁶は、一般式（１）と同義であり；ｎ、ｍ、ｌおよびｐは、同一または異なって１〜３の整数である）のジアミン化合物が好ましく、一般式（１）のＹ¹、Ｙ²、Ｙ³、Ｙ⁴、Ｙ⁵およびＹ⁶が鎖状のメチレン基であるジアミン化合物、すなわち副式（３）：

(In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ have the same meanings as in the general formula (1); n, m, l and p are the same or different and represent 1 to 3 A diamine compound of the general formula (1), wherein Y ¹ , Y ² , Y ³ , Y ⁴ , Y ⁵ and Y ^{6 in} the general formula (1) are chain methylene groups, that is, the sub-formula (3) :

（式中、Ａｒ¹、Ａｒ²、Ａｒ³、Ａｒ⁴、Ａｒ⁵およびＡｒ⁶は、一般式（１）と同義である）で示されるジアミン化合物が特に好ましい。

A diamine compound represented by the formula (wherein Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ have the same meanings as in the general formula (1)) is particularly preferred.

The substituents in the general formula (I), sub-formula (II) and sub-formula (III) will be described.
Examples of the aryl group that may have a substituent of Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, Examples thereof include a dialkylamino group having 2 to 6 carbon atoms or an aryl group which may be substituted with a halogen atom.

Examples of the aryl group include a phenyl group and a naphthyl group.
Examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, and tert-butyl group.
Examples of the alkoxy group having 1 to 4 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, an isopropoxy group, and an isobutoxy group.
Examples of the dialkylamino group having 2 to 6 carbon atoms include a dimethylamino group, a diethylamino group, and a dipropylamino group.
Examples of the halogen atom include a chlorine atom, a bromine atom, and an iodine atom.

  Specifically, phenyl group, o-tolyl group, 2,4-xylyl group, 4-methoxyphenyl group, 3-methoxy-4-methylphenyl group, t-butylphenyl group, 4-diethylaminophenyl group, 4- Examples include chlorophenyl group, 4-fluorophenyl group, 1-naphthyl group, 2-naphthyl group and the like. Among these, phenyl group, o-tolyl group, 4-methoxyphenyl group, 1-naphthyl group, 2-naphthyl group Is particularly preferred.

Examples of the cycloalkyl group which may have a substituent of Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ include a cycloalkyl optionally substituted with an alkyl group having 1 to 4 carbon atoms. Groups.

Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group.
Said alkyl group is mentioned as a C1-C4 alkyl group.

  Specific examples include a cyclohexyl group, a cyclopentyl group, a 4,4-dimethylcyclohexyl group, and among these, a cyclohexyl group is particularly preferable.

Examples of the hetero atom-containing cycloalkyl group which may have a substituent for Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ include a tetrahydrofuryl group and a tetramethyltetrahydrofuryl group.

The monovalent heterocyclic residue which may have a substituent of Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ is, for example, substituted with an alkyl group having 1 to 4 carbon atoms. And monovalent heterocyclic residues may be mentioned.
Specific examples include a furyl group, a 4-methylfuryl group, a benzofuryl group, and a benzothiophenyl group. Among these, a furyl group and a benzofuryl group are particularly preferable.

Examples of the chain alkylene group that may have a substituent of Y ¹ , Y ² , Y ^3, and Y ⁴ include an alkylene group that may be substituted with an alkyl group having 1 to 4 carbon atoms.
Specific examples include a methylene group, an ethylene group, a trimethylene group, and a 2,2-dimethyltrimethylene group. Among these, a methylene group and an ethylene group are particularly preferable.

Specific examples of the diamine compound of the present invention are shown in Table 1.
In Tables 1-1 to 1-6, substituents are represented by the following abbreviations.
-Me-: methylene group -Et-: ethylene group -Tr-: trimethylene group -Dm-: 2,2-dimethyltrimethylene group

  Among the diamine compounds of the present invention shown in Tables 1-1 to 1-6, Exemplified Compound Nos. 1, 2, 3, 4, 15, 20, 28, 48, 51 and 59 are preferred. 1, 2, 3, 4, 15 and 20 are particularly preferred.

  The diamine compound of the present invention can be produced by the method shown in the following reaction scheme. That is, by heating the amine compound represented by the general formula (4) and the general formula (5) and the dihalogen compound represented by the general formula (6) in the presence of an organic amine base, the yield can be easily increased. The target product can be produced with high purity.

（式中、Ａｒ¹、Ａｒ²、Ａｒ³、Ａｒ⁴、Ａｒ⁵、Ａｒ⁶、Ｙ¹、Ｙ²、Ｙ³およびＹ⁴は、一般式（１）と同義であり；Ｘ¹およびＸ²はハロゲン原子を示す）
反応式におけるＸ¹およびＸ²のハロゲン原子としては、塩素原子、臭素原子、ヨウ素原子が挙げられ、これらの中でも、塩素原子、臭素原子が特に好ましい。 [Reaction formula]

(Wherein Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ , Y ¹ , Y ² , Y ³ and Y ⁴ have the same meanings as in the general formula (1); X ¹ and X ² Represents a halogen atom)
Examples of the halogen atom of X ¹ and X ² in the reaction formula include a chlorine atom, a bromine atom, and an iodine atom, and among these, a chlorine atom and a bromine atom are particularly preferable.

The reaction of the above reaction formula can be carried out, for example, as follows.
The secondary amine compounds (4) and (5) and the dihalogen compound (6) are dissolved or dispersed in a solvent, an organic amine base is added thereto, and the mixture is heated and stirred. After completion of the reaction, the precipitate is filtered off and recrystallized in ethanol, methanol, ethyl acetate or the like alone or in a mixed solvent system, whereby the target product can be obtained easily and with high purity in high yield.

The solvent is not particularly limited as long as it is inert to the above reaction and can dissolve or disperse the reaction substrate and the organic amine base. Specifically, aromatic hydrocarbons such as toluene and xylene; ethers such as diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether and 1,4-dioxane; amides such as N, N-dimethylformamide; dimethyl sulfoxide and the like Examples thereof include sulfoxides, and these can be used alone or as a mixed solvent.
The amount of the solvent used is not particularly limited, and the amount by which the reaction smoothly proceeds may be appropriately set according to the reaction conditions such as the amount of the reaction substrate used, the reaction temperature, and the reaction time.
Examples of the organic amine base include N, N-diisopropylethylamine, N, N-dimethylaminopyridine, 1,4-diazabicycloundecene and the like.

The ratio of the secondary amine compounds (4) and (5) to the dihalogen compound (6) is not particularly limited.
For example, when a symmetrical compound is obtained (when only one of the secondary amine compound (4) and (5) is used), 1 equivalent of the dihalogen compound (6) is taken into consideration in view of the efficiency of the reaction. The secondary amine compound is preferably used in an amount of about 2.0 to 2.3 equivalents.
In addition, when obtaining an asymmetric compound (when using both the secondary amine compounds (4) and (5)), the reaction efficiency and the like are taken into consideration with respect to 1 equivalent of the dihalogen compound (6). Each secondary amine compound is preferably used in an amount of about 1.0 to 1.2 equivalents (the total of the secondary amine compounds (4) and (5) is about 2.0 to 2.4 equivalents).

The use ratio of the dihalogen compound (6) and the organic amine base is not particularly limited, but considering the reaction efficiency and the like, the organic amine base is used in an amount of 2. with respect to 1 equivalent of the dihalogen compound (6). It is preferable to use about 05 to 5.0 equivalents.
Moreover, although heating temperature and reaction time are not specifically limited, Considering reaction efficiency etc., it is preferable to make it react at 60-120 degreeC for 2 to 8 hours, although it is based also on the solvent to be used.

  The diamine compound of the present invention is excellent in ozone resistance. Therefore, the photoreceptor containing the diamine compound of the present invention in the surface protective layer has excellent electrophotographic characteristics, is not easily affected by ozone and nitrogen oxides generated from the system, and has stable characteristics even when used repeatedly. It has image quality and can achieve extremely high durability.

Next, the configuration of the photoreceptor of the present invention will be specifically described.
1 to 4 are schematic cross-sectional views showing the configuration of the main part of the photoreceptor of the present invention.
FIG. 1 and FIG. 2 are schematic cross-sectional views showing the configuration of the main part of a single-layer type photoreceptor that is a single-layer type photosensitive layer having a single photosensitive layer.
3 and 4 show a multilayer photosensitive body (hereinafter referred to as “functional separation type”) in which the photosensitive layer is a multilayer photosensitive layer (hereinafter also referred to as “functional separation type photosensitive layer”) composed of a charge generation layer and a charge transport layer. 2 is a schematic cross-sectional view showing a configuration of a main part of a photoconductor ”. The photoreceptor of the present invention may have a reverse two-layered laminated structure in which a charge generating layer and a charge transporting layer are formed in reverse order, but the laminated type is preferred.

In the photoreceptor 12 of FIG. 1, a single-layer type photosensitive layer 2 and a surface protective layer 5 are formed in this order on the surface of a conductive support 1.
2, the intermediate layer 6, the single-layer type photosensitive layer 2, and the surface protective layer 5 are formed on the surface of the conductive support 1 in this order.

3 has a laminated photosensitive layer 7 in which the charge generation layer 3 and the charge transport layer 4 are laminated in this order on the surface of the conductive support 1, and the surface protective layer 5 in this order. Is formed.
4 includes an intermediate layer 6, a charge generating layer 3 and a charge transport layer 4 laminated in this order on the surface of the conductive support 1, and a surface protective layer 5. Are formed in this order.

[Conductive support 1 (photosensitive element tube)]
The constituent material of the conductive support is not particularly limited as long as it is a material used in this field.
Specifically, metallic materials such as aluminum, aluminum alloys, copper, zinc, stainless steel, titanium: substrate surface made of polymer materials such as polyethylene terephthalate, polyamide, polyester, polyoxymethylene, polystyrene, hard paper, glass, etc. And metal foil laminated, metal material deposited, conductive polymer, tin oxide, indium oxide or other conductive compound layer deposited or applied.

The shape of the conductive support is not limited to a sheet shape as shown in FIGS. 1 to 4, and may be a cylindrical shape, a columnar shape, an endless belt shape, or the like.
If necessary, the surface of the conductive support 1 is irregularly reflected within a range that does not affect the image quality, such as anodized film treatment, surface treatment with chemicals, hot water, coloring treatment, or roughening the surface. It may be processed.

  The irregular reflection treatment is particularly effective when the photoreceptor according to the present invention is used in an electrophotographic process using a laser as an exposure light source. That is, in the electrophotographic process using a laser as an exposure light source, the wavelength of the laser beam is uniform, so the laser beam reflected on the surface of the photoconductor and the laser beam reflected inside the photoconductor cause interference, Interference fringes due to this interference may appear in the image and cause image defects. Therefore, by performing irregular reflection processing on the surface of the conductive support, it is possible to prevent image defects due to interference of laser light having a uniform wavelength.

[Single-layer type photosensitive layer 2]
The single-layer type photosensitive layer contains a charge generation material, a charge transport material, and a binder resin.

The charge generation material has an ability to generate charges by absorbing light.
As the charge generation material, a compound used in this field can be used.
Specifically, azo pigments (monoazo pigments, bisazo pigments, trisazo pigments, etc.), indigo pigments (indigo, thioindigo, etc.), perylene pigments (perylene imide, perylene acid anhydride, etc.), polycyclic quinone pigments Pigments (anthraquinone, pyrenequinone, etc.), phthalocyanine pigments (metal phthalocyanine, X-type metal-free phthalocyanine, etc.), organic pigments or dyes such as squarylium dyes, pyrylium salts, thiopyrylium salts, triphenylmethane dyes, selenium, amorphous Examples thereof include inorganic materials such as silicon. These charge generating materials can be used alone or in combination of two or more.

Among these charge generation materials, phthalocyanine pigments such as metal phthalocyanine and X-type metal-free phthalocyanine are preferable, and oxotitanium phthalocyanine is particularly preferable.
Since phthalocyanine pigments have high charge generation efficiency and charge injection efficiency, they generate a large amount of charge by absorbing light, and in the single layer type photosensitive layer without accumulating the generated charge in the molecule. Since charges are efficiently injected into the contained charge transport material and smoothly transported, a highly sensitive and high resolution photoreceptor can be obtained. This effect is the same for the laminated type photoconductor described later.

Charge generating materials can be used in combination with sensitizing dyes.
Examples of such sensitizing dyes include triphenylmethane dyes typified by methyl violet, crystal violet, knight blue and victoria blue; acridines typified by erythrosine, rhodamine B, rhodamine 3R, acridine orange and frappeosin. Dyes; thiazine dyes typified by methylene blue and methylene green; oxazine dyes typified by capri blue and meldra blue; cyanine dyes; styryl dyes; pyrylium salt dyes and thiopyrylium salt dyes.

The charge transport material has an ability to accept and transport charges generated by the charge generation material, and includes a hole transport material and an electron transport material.
As the hole transport material, a compound used in this field can be used.
Specifically, carbazole derivatives, pyrene derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds, hydrazone compounds, many Ring aromatic compounds, indole derivatives, pyrazoline derivatives, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, triarylmethane derivatives, phenylenediamine derivatives, stilbene derivatives , Enamine derivatives, benzidine derivatives, polymers having groups derived from these compounds in the main chain or side chain (Polymers) -N- vinylcarbazole, poly-1-vinylpyrene, ethylcarbazole - formaldehyde resins, triphenylmethane polymers, poly-9-vinyl anthracene, etc.), etc. polysilane and the like.

Moreover, as an electron transport substance, the compound used in the said field | area can be used.
Specifically, organic compounds such as benzoquinone derivatives, tetracyanoethylene derivatives, tetracyanoquinodimethane derivatives, fluorenone derivatives, xanthone derivatives, phenanthraquinone derivatives, phthalic anhydride derivatives, diphenoquinone derivatives, amorphous silicon, amorphous selenium, Examples include inorganic materials such as tellurium, selenium-tellurium alloy, cadmium sulfide, antimony sulfide, zinc oxide, and zinc sulfide. These charge transport materials can be used alone or in combination of two or more.

  As the binder resin, for example, a resin having a binding property used in this field can be used for the purpose of improving the mechanical strength, durability, etc. of the single-layer type photosensitive layer, and the diamine compound of the present invention can be used. Those having excellent compatibility are preferred.

  Specifically, vinyl resins such as polymethyl methacrylate, polystyrene, polyvinyl chloride, polycarbonate, polyester, polyester carbonate, polysulfone, polyarylate, polyamide, methacrylic resin, acrylic resin, polyether, polyacrylamide, polyphenylene oxide, etc. Thermoplastic resin: Thermosetting resin such as phenoxy resin, epoxy resin, silicone resin, polyurethane, phenol resin, alkyd resin, melamine resin, phenoxy resin, polyvinyl butyral, polyvinyl formal, partially cross-linked products of these resins, these resins Copolymer resins containing two or more of the structural units contained in (vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, acrylo Tolyl - insulating resin such as styrene copolymer resin). These binder resins can be used alone or in combination of two or more.

Among these resins, polystyrene, polycarbonate, polyarylate, and polyphenylene oxide are particularly excellent in compatibility with the diamine compound of the present invention, and further have a volume resistance of 10 ¹³ Ω or more, excellent electrical insulation, and composition. Polycarbonate is particularly preferred because it is excellent in film properties, potential characteristics, and the like.

In addition, the single-layer type photosensitive layer may contain an additive such as an antioxidant used in this field. Such an additive is preferable because the stability as a coating solution for forming a photosensitive layer is increased and the life of the solution is extended, and the photoreceptor produced with the coating solution is also reduced in oxidizing impurities and improved in durability.
Examples of the antioxidant include hindered phenol derivatives and hindered amine derivatives.

The ratio C / D between the weight C of the antioxidant and the total weight D of the charge transport material and the binder resin is the ratio A between the weight A of the diamine compound and the weight B of the binder resin in the surface protective layer described later. It is preferably lower than / B.
Furthermore, the weight of the antioxidant is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the charge transport material.
When the amount of the antioxidant used is less than 0.1 parts by weight, the stability of the coating solution for forming a photosensitive layer, which will be described later, the durability of the photoreceptor and the durability of the photoreceptor may be insufficient. Further, when the ratio C / D exceeds the ratio A / B, or when the amount of the antioxidant used exceeds 10 parts by weight, the electrical characteristics of the photoreceptor may be adversely affected.

  The single-layer type photosensitive layer 2 is prepared by dissolving a charge generating material, a charge transporting material, a binder resin, and, if necessary, an additive such as an antioxidant for enhancing the overall stability of the photoreceptor in an appropriate organic solvent. Alternatively, a coating solution for forming a photosensitive layer is prepared by dispersing, and this coating solution is applied to the surface of the conductive support 1 or the surface of the intermediate layer 6 formed on the conductive support 1, and then dried. It can be formed by removing the organic solvent. More specifically, for example, a coating solution for forming a single-layer photosensitive layer is prepared by dissolving or dispersing a constituent material in a resin solution obtained by dissolving a binder resin in an organic solvent.

  Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, xylene, mesitylene, tetralin, diphenylmethane, dimethoxybenzene, and dichlorobenzene; halogenated hydrocarbons such as dichloromethane, dichloroethane, and tetrachloropropane; tetrahydrofuran (THF) , Ethers such as dioxane, dibenzyl ether, dimethoxymethyl ether, 1,2-dimethoxyethane; ketones such as methyl ethyl ketone, cyclohexanone, acetophenone, isophorone; esters such as methyl benzoate, ethyl acetate, butyl acetate, diphenyl sulfide Sulfur-containing solvents such as: Fluorinated solvents such as hexafluoroisopropanol; non-protons such as N, N-dimethylformamide and N, N-dimethylacetamide Such as a polar solvent and the like, which may be used alone or as a mixed solvent. A mixed solvent obtained by adding alcohols, acetonitrile, or methyl ethyl ketone to such a solvent can also be used.

Prior to dissolving or dispersing the constituent materials in the resin solution, the charge generating material and other additives may be pre-ground.
The preliminary pulverization can be performed using a general pulverizer such as a ball mill, a sand mill, an attritor, a vibration mill, or an ultrasonic disperser.
The dissolution or dispersion of the constituent materials in the resin solution can be performed using, for example, a general disperser such as a paint shaker, a ball mill, or a sand mill. At this time, it is preferable to appropriately set the dispersion condition so that impurities are generated from the container and the members constituting the disperser due to wear and the like and are not mixed into the coating liquid.
Examples of the coating method of the single layer type photosensitive layer forming coating solution include roll coating, spray coating, blade coating, ring coating, and dip coating.

  Although the film thickness of a single layer type photosensitive layer is not specifically limited, 5-100 micrometers is preferable and 10-50 micrometers is especially preferable. If the film thickness of the single-layer type photosensitive layer is less than 5 μm, the charge holding ability on the surface of the photoreceptor may be lowered. Conversely, if the film thickness of the single-layer type photosensitive layer exceeds 100 μm, the productivity of the photoreceptor is reduced. There is a risk.

[Laminated Photosensitive Layer 7]
The laminated photosensitive layer is composed of a charge generation layer 3 and a charge transport layer 4.

[Charge generation layer 3]
The charge generation layer 3 contains a charge generation material and a binder resin.
As the charge generation material, one or more of the same charge generation materials as those contained in the single-layer type photosensitive layer can be used.
As the binder resin, one or more of the same binder resins as those contained in the single-layer type photosensitive layer can be used. Among these, polyvinyl butyral is particularly preferable.

The use ratio of the charge generation material and the binder resin is not particularly limited. Preferably, the charge generation material is contained in an amount of 10 to 99% by weight in the total amount of the charge generation material and the binder resin, and the balance is the binder resin. It is.
If the ratio of the charge generation material is less than 10% by weight, the sensitivity may be lowered. Conversely, if the ratio of the charge generation material exceeds 99% by weight, not only the film strength of the charge generation layer is decreased, but also the charge generation. This is called a black spot where the dispersibility of the substance decreases and the coarse particles increase, the surface charge other than that which should be erased by exposure decreases, and image defects, especially toner adheres to the white background and minute black spots are formed. There is a possibility that a lot of fogging of the image occurs.

  In addition to the two essential components, the charge generation layer may be one or more selected from a hole transport material, an electron transport material, an antioxidant, a dispersion stabilizer, a sensitizer, and the like, if necessary. Each may contain an appropriate amount. As a result, the potential characteristics are improved, the stability of the coating solution for forming a charge generation layer, which will be described later, is increased, fatigue deterioration during repeated use of the photoreceptor is reduced, and durability can be improved.

The charge generation layer 3 is prepared by dissolving or dispersing a charge generation material, a binder resin and, if necessary, other additives in an appropriate organic solvent to prepare a coating solution for forming a charge generation layer. It can be formed by applying to the surface of the body 1 or the surface of the intermediate layer 6 formed on the conductive support 1, and then drying to remove the organic solvent. More specifically, for example, a charge generating layer forming coating solution is prepared by dissolving or dispersing a charge generating substance and other additives as required in a resin solution obtained by dissolving a binder resin in an organic solvent. To do.
Other processes and conditions are in accordance with the formation of the single-layer type photosensitive layer.
The organic solvent can use 1 type (s) or 2 or more types of the same solvent as what is used for preparation of the coating liquid for formation of a single layer type photosensitive layer.

  The thickness of the charge generation layer 3 is not particularly limited, but is preferably 0.05 to 5 μm, and particularly preferably 0.1 to 1 μm. This is because if the film thickness of the charge generation layer is less than 0.05 μm, the efficiency of light absorption may be reduced and the sensitivity may decrease. Conversely, if the film thickness of the charge generation layer exceeds 5 μm, In this case, the charge transport in this process becomes a rate-determining step in the process of erasing the charge on the surface of the photoreceptor, and the sensitivity may be lowered.

[Charge transport layer 4]
The charge transport layer 4 contains a charge transport material and a binder resin.
As the diamine compound of the present invention, one or more of the same diamine compounds as those contained in the single-layer type photosensitive layer can be used.
As the charge transport material, one or more of the same charge transport materials as those contained in the single-layer type photosensitive layer can be used.
As the binder resin, one or more of the same binder resins as those contained in the single-layer type photosensitive layer can be used.

Further, the charge transport layer may contain an additive such as an antioxidant used in this field, and examples thereof include the same antioxidant as that contained in the single-layer type photosensitive layer.
The ratio C / D between the weight C of the antioxidant and the total weight D of the charge transport material and the binder resin is the ratio A between the weight A of the diamine compound and the weight B of the binder resin in the surface protective layer described later. It is preferably lower than / B.
If the ratio C / D exceeds the ratio A / B, the electrical characteristics of the photoreceptor may be adversely affected.

The charge transport layer 4 is prepared by dissolving or dispersing a charge transport material, a binder resin and, if necessary, an additive such as an antioxidant for enhancing the overall stability of the photoreceptor in an appropriate organic solvent. It can be formed by preparing a coating solution for forming, applying this coating solution to the surface of the charge generation layer 3, and then drying to remove the organic solvent. More specifically, for example, the charge transport layer is prepared by dissolving or dispersing the charge transport material, the diamine compound of the present invention and, if necessary, other additives in a resin solution obtained by dissolving a binder resin in an organic solvent. A forming coating solution is prepared.
Other processes and conditions are in accordance with the formation of the single-layer type photosensitive layer.

  The thickness of the charge transport layer 4 is not particularly limited, but is preferably 5 to 50 μm, and particularly preferably 10 to 40 μm. If the thickness of the charge transport layer is less than 5 μm, the charge holding ability on the surface of the photoreceptor may be lowered. Conversely, if the thickness of the charge transport layer exceeds 50 μm, the resolution of the photoreceptor may be lowered.

[Surface protective layer]
The surface protective layer 5 has a function of improving the durability of the photoreceptor, and contains the diamine compound of the present invention and a binder resin.
As the diamine compound of the present invention, one or more of the above compounds can be used.
As the binder resin, one or more of the same binder resins as those contained in the single-layer type photosensitive layer can be used. Among these resins, polystyrene, polycarbonate, polyarylate, and polyphenylene oxide are particularly excellent in compatibility with the diamine compound of the present invention, and further have a volume resistance of 10 ¹³ Ω or more, excellent electrical insulation, and composition. Polycarbonate is particularly preferred because it is excellent in film properties, potential characteristics, and the like.

The ratio A / B between the weight A of the diamine compound of the present invention and the weight B of the binder resin is preferably from 0.1 / 100 to 30/100, more preferably from 1/100 to 20/100. Particularly preferred.
When the ratio A / B is less than 0.1 / 100 parts, the effect of the present invention may be insufficient. Moreover, when ratio A / B exceeds 30/100, the relative quantity ratio with respect to resin of a diamine compound may become high, and phenomena, such as a sensitivity falling, may be exhibited.

For example, the surface protective layer 5 is prepared by dissolving or dispersing the diamine compound and binder resin of the present invention in an appropriate organic solvent to prepare a coating solution for forming a surface protective layer. It can be formed by coating on the surface of the photosensitive layer 2 or the laminated photosensitive layer 7 and removing the organic solvent by drying. As the organic solvent used here, the same organic solvent used for forming the photosensitive layer 2 can be used.
Other processes and conditions are in accordance with the formation of the single-layer type photosensitive layer.
The organic solvent can use 1 type (s) or 2 or more types of the same solvent as what is used for preparation of the coating liquid for formation of a single layer type photosensitive layer.

  The thickness of the surface protective layer 5 is not particularly limited, but is preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm. If the thickness of the surface protective layer 5 is less than 0.5 μm, the surface resistance of the photoreceptor is inferior and the durability may be insufficient. Conversely, if it exceeds 10 μm, the resolution of the photoreceptor may be reduced. There is.

[Intermediate layer 6]
The photoreceptor of the present invention preferably has an intermediate layer between the conductive support and the single layer type photosensitive layer or the multilayer type photosensitive layer.
The intermediate layer has a function of preventing charge injection from the conductive support to the single-layer type photosensitive layer or the laminated type photosensitive layer. That is, the decrease in chargeability of the single-layer type photosensitive layer or the multilayer type photosensitive layer is suppressed, the decrease in surface charge other than the portion to be erased by exposure is suppressed, and the occurrence of image defects such as fog is prevented. In particular, during image formation by the reversal development process, it is possible to prevent the occurrence of image fogging called black spots in which minute black dots made of toner are formed on a white background portion.
The intermediate layer covering the surface of the conductive support with the intermediate layer reduces the degree of unevenness, which is a defect on the surface of the conductive support, and makes the surface uniform. It is possible to improve the film formability and improve the adhesion between the conductive support and the single-layer type photosensitive layer or the multilayer type photosensitive layer.

The intermediate layer is formed, for example, by dissolving a resin material in an appropriate solvent to prepare a coating solution for forming an intermediate layer, applying this coating solution to the surface of the conductive support, and removing the organic solvent by drying. it can.
Examples of the resin material include natural polymeric materials such as casein, gelatin, polyvinyl alcohol, and ethyl cellulose in addition to the same binder resin as that contained in the single-layer type photosensitive layer, and one or more of these may be used. Can be used.
Examples of the solvent for dissolving or dispersing the resin material include water, alcohols such as methanol, ethanol and butanol, glymes such as methyl carbitol and butyl carbitol, and mixed solvents in which two or more of these solvents are mixed. Can be mentioned.
Other processes and conditions are in accordance with the formation of the single-layer type photosensitive layer.

Moreover, the coating liquid for intermediate | middle layer formation may contain the metal oxide particle.
The metal oxide particles can easily adjust the volume resistivity of the intermediate layer, further suppress charge injection into the single-layer type photosensitive layer or multilayer type photosensitive layer, and maintain the electrical characteristics of the photoconductor in various environments. it can.
Examples of the metal oxide particles include titanium oxide, aluminum oxide, aluminum hydroxide, and tin oxide.
When the total content of the resin material and the metal oxide particles in the coating liquid for forming the intermediate layer is E and the content of the solvent is F, the volume ratio (E / F) of both is 1/99 to 40/60. (Weight ratio = 0.01 to 0.67) is preferable, and 2/98 to 30/70 (weight ratio = 0.02 to 0.43) is particularly preferable.
The volume ratio (G / H) between the resin material content (G) and the metal oxide particle content (H) is 1/99 to 90/10 (weight ratio = 0.01 to 9.0). ) Is preferable, and 5/95 to 70/30 (weight ratio = 0.05 to 2.33) is particularly preferable.

Although the film thickness of an intermediate | middle layer is not specifically limited, 0.01-20 micrometers is preferable and 0.1-10 micrometers is especially preferable. If the thickness of the intermediate layer is less than 0.01 μm, it may not function substantially as the intermediate layer, and there is a possibility that a uniform surface cannot be obtained by covering the defects of the conductive support, and the thickness of the intermediate layer is 20 μm. If it exceeds 1, it is difficult to form a uniform intermediate layer, and the sensitivity of the photoreceptor may be lowered.
In addition, when the constituent material of an electroconductive support body is aluminum, the layer (alumite layer) containing an alumite can be formed and it can be set as an intermediate | middle layer.

  An image forming apparatus according to the present invention includes a photosensitive member according to the present invention, a charging unit that charges the photosensitive member, an exposure unit that exposes the charged photosensitive member, and an electrostatic latent image formed by exposure. And developing means for developing.

The image forming apparatus of the present invention will be described with reference to the drawings, but is not limited to the following description.
FIG. 9 is a schematic side view showing the configuration of the image forming apparatus of the present invention.
The image forming apparatus 20 in FIG. 9 includes a photoreceptor 21 of the present invention (for example, any one of the photoreceptors 11 to 18 in FIGS. 1 to 8), a charging unit (charger) 24, an exposure unit 28, A developing unit (developing device) 25, a transfer device 26, a cleaner 27, and a fixing device 31 are included. Reference numeral 30 indicates a transfer sheet.

  The photosensitive member 21 is rotatably supported by the main body of the image forming apparatus 20 (not shown), and is driven to rotate in the direction of the arrow 23 around the rotation axis 22 by a driving unit (not shown). The drive means includes, for example, an electric motor and a reduction gear, and transmits the driving force to a conductive support constituting the core of the photoconductor 21, thereby rotating the photoconductor 21 at a predetermined peripheral speed. . The charger 24, the exposure unit 28, the developing unit 25, the transfer unit 26, and the cleaner 27 are arranged in this order along the outer peripheral surface of the photoconductor 21 from the upstream side in the rotation direction of the photoconductor 21 indicated by the arrow 23. It is provided toward the side.

The charger 24 is a charging unit that charges the outer peripheral surface of the photoconductor 21 to a predetermined potential. In the present embodiment, the charger 24 is realized by a contact-type charging roller 24a and a bias power source 24b that applies a voltage to the charging roller 24a.
Although a charger wire can be used as the charging means, in a charging roller that requires high wear resistance on the surface of the photoconductor, the photoconductor on which the surface protective layer according to the present invention is formed exhibits a great effect by improving durability.
Therefore, in the image forming apparatus of the present invention, the charging unit is preferably a contact charging unit.

  The exposure unit 28 includes, for example, a semiconductor laser as a light source, and is charged by irradiating light 28 a such as a laser beam output from the light source between the charger 24 and the developing unit 25 of the photosensitive member 21. The outer peripheral surface of the photoconductor 21 is exposed according to image information. The light 28a is repeatedly scanned in the main scanning direction in the direction in which the rotation axis 22 of the photoconductor 21 extends, and accordingly, electrostatic latent images are sequentially formed on the surface of the photoconductor 21.

  The developing unit 25 is a developing unit that develops an electrostatic latent image formed on the surface of the photoreceptor 21 by exposure with a developer. The developing unit 25 is provided facing the photoreceptor 21, and applies toner to the outer peripheral surface of the photoreceptor 21. A developing roller 25a to be supplied and a casing 25b for supporting the developing roller 25a so as to be rotatable around a rotation axis parallel to the rotation axis 22 of the photosensitive member 21 and containing a developer containing toner in the internal space thereof.

  The transfer device 26 supplies a toner image, which is a visible image formed on the outer peripheral surface of the photoconductor 21 by development, between the photoconductor 21 and the transfer device 26 from the direction of the arrow 29 by a conveying unit (not shown). It is a transfer means for transferring onto the transfer paper 30 as a recording medium. The transfer unit 26 is, for example, a non-contact type transfer unit that includes a charging unit and transfers the toner image onto the transfer paper 30 by applying a charge having a polarity opposite to that of the toner to the transfer paper 30.

  The cleaner 27 is a cleaning unit that removes and collects toner remaining on the outer peripheral surface of the photoconductor 21 after the transfer operation by the transfer device 26, and includes a cleaning blade 27 a that peels off toner remaining on the outer peripheral surface of the photoconductor 21, and a cleaning device. A recovery casing 27b for storing the toner separated by the blade 27a. The cleaner 27 is provided together with a charge eliminating lamp (not shown).

  Further, the image forming apparatus 20 is provided with a fixing device 31 as fixing means for fixing the transferred image on the downstream side where the transfer paper 30 that has passed between the photoreceptor 21 and the transfer device 26 is conveyed. . The fixing device 31 includes a heating roller 31a having a heating unit (not shown), and a pressure roller 31b that is provided to face the heating roller 31a and is pressed by the heating roller 31a to form a contact portion.

  The image forming operation by the image forming apparatus 20 is performed as follows. First, when the photosensitive member 21 is rotationally driven in the direction of the arrow 23 by the driving unit, the photosensitive member is provided by the charger 24 provided on the upstream side in the rotational direction of the photosensitive member 21 with respect to the imaging point of the light 28a by the exposure unit 28. The surface of 21 is uniformly charged to a predetermined positive or negative potential.

Next, light 28 a corresponding to image information is irradiated from the exposure unit 28 to the surface of the photoconductor 21. With this exposure, the surface charge of the portion irradiated with the light 28a is removed from the photosensitive member 21, and a difference occurs between the surface potential of the portion irradiated with the light 28a and the surface potential of the portion not irradiated with the light 28a. An electrostatic latent image is formed.
Toner is supplied to the surface of the photosensitive member 21 on which the electrostatic latent image is formed from a developing unit 25 provided on the downstream side in the rotation direction of the photosensitive member 21 with respect to the image forming point of the light 28a by the exposure means 28, and electrostatic latent The image is developed to form a toner image.

In synchronization with the exposure of the photosensitive member 21, the transfer paper 30 is supplied between the photosensitive member 21 and the transfer device 26. The transfer device 26 applies a charge having a polarity opposite to that of the toner to the supplied transfer paper 30, and the toner image formed on the surface of the photoreceptor 21 is transferred onto the transfer paper 30.
The transfer paper 30 onto which the toner image has been transferred is conveyed to a fixing device 31 by a conveying means, and is heated and pressurized when passing through a contact portion between a heating roller 31a and a pressure roller 31b of the fixing device 31, and toner The image is fixed on the transfer paper 30 and becomes a robust image. The transfer paper 30 on which the image is formed in this way is discharged to the outside of the image forming apparatus 20 by the conveying means.

On the other hand, the toner remaining on the surface of the photoconductor 21 even after the transfer of the toner image by the transfer unit 26 is separated from the surface of the photoconductor 21 by the cleaner 27 and collected. The charge on the surface of the photoconductor 21 from which the toner has been removed in this manner is removed by the light from the static elimination lamp, and the electrostatic latent image on the surface of the photoconductor 21 disappears. Thereafter, the photosensitive member 21 is further driven to rotate, and a series of operations starting from charging again is repeated to continuously form images.
Since the image forming apparatus 20 according to the present invention includes the photoreceptor 21 having the photosensitive layer in which the diamine compound of the present invention is uniformly dispersed, it is possible to form a high quality image free from image defects such as black spots.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1
Exemplified Compound No. which is a diamine compound according to the present invention is as follows. A photoconductor having 1 in the surface protective layer was prepared. As the conductive support, an aluminum element tube having a length of 340 mm, an outer diameter of 30 mm, and a thickness of 1 mm was used.

  7 parts by weight of titanium oxide (trade name: Taibake TTO55A, manufactured by Ishihara Sangyo Co., Ltd.) and 13 parts by weight of copolymer nylon resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.), 159 parts by weight of methyl alcohol and 1,3- In addition to a mixed solvent with 106 parts by weight of dioxolane, dispersion treatment was carried out for 8 hours with a paint shaker to prepare 50 liters of an intermediate layer forming coating solution. This intermediate layer forming coating solution was applied to an aluminum base tube as a conductive support by a dip coating method and naturally dried to form an intermediate layer having a thickness of 1 μm.

  Next, 1 part by weight of X-type metal-free phthalocyanine (Fastogen Blue 8120, manufactured by Dainippon Ink) and 1 part by weight of butyral resin (trade name: # 6000-C, manufactured by Denki Kagaku Kogyo Co., Ltd.) were added to 98 parts by weight of methyl ethyl ketone. The mixture was mixed and dispersed with a paint shaker to prepare 50 liters of a coating solution for forming a charge generation layer. This charge generation layer forming coating solution was applied to the surface of the previously provided intermediate layer in the same manner as the above intermediate layer and naturally dried to form a charge generation layer having a thickness of 0.4 μm.

  Next, 100 parts by weight of the charge transport material represented by the following structural formula (4) and 180 parts by weight of a polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) are mixed, and the solid content is 10% by weight using toluene as a solvent. A 50 liter coating solution for forming a charge transport layer was prepared. By applying the coating liquid for forming the charge transport layer to the surface of the charge generation layer previously provided by adjusting the coating speed so as to be 15 μm and 28 μm, respectively, in the same manner as the above intermediate layer, Charge transport layers having different thicknesses were formed.

Exemplified Compound No. which is a diamine compound of the present invention. 1 0.75 parts by weight and 30 parts by weight of polycarbonate resin (trade name: Iupilon Z400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) are mixed, and 50 liters of a coating solution for forming a surface protective layer having a solid content of 10% by weight using cyclohexanone as a solvent. Prepared. A surface protective layer was formed on the surface of the charge transport layer previously provided with this surface protective layer forming coating solution in the same manner as the intermediate layer so as to have a film thickness of 1 μm.
Thus, like the photoreceptor 18 shown in FIG. 4, the laminate according to the present invention has a laminated structure in which an intermediate layer, a charge generation layer, a charge transport layer, and a surface protective layer are sequentially laminated on a conductive support. A mold photoreceptor was prepared.

(Examples 2 to 4)
Exemplified compound No. which is a diamine compound according to the present invention. In place of Exemplified Compound No. 1 According to the present invention, which has a laminated structure in which an intermediate layer, a charge generation layer, a charge transport layer and a surface protective layer are sequentially laminated on a conductive support in the same manner as in Example 1 except that 2, 28 and 59 are used. A laminated photoreceptor was prepared.

(Example 5)
Exemplified Compound No. In the same manner as in Example 1 except that 0.03 part by weight of the diamine compound 1 was used, a laminated structure in which an intermediate layer, a charge generation layer, a charge transport layer, and a surface protective layer were sequentially laminated on a conductive support. A multilayer photoreceptor according to the present invention was prepared.

(Example 6)
Exemplified Compound No. A book having a laminated structure in which an intermediate layer, a charge generation layer, a charge transport layer, and a surface protective layer are sequentially laminated on a conductive support in the same manner as in Example 1 except that 9 parts by weight of the diamine compound 1 was used. A laminated photoreceptor according to the invention was prepared.

(Example 7)
Except that 5.6 parts by weight of 2,6-di-t-butyl-4-methylphenol (BHT) was used for the charge transport layer, the same procedure as in Example 1 was carried out. A multilayer photoreceptor according to the present invention having a multilayer structure in which a layer, a charge transport layer, and a surface protective layer were sequentially laminated was produced.

(Example 8)
A laminate in which an intermediate layer, a charge generation layer, a charge transport layer, and a surface protective layer are sequentially laminated on a conductive support in the same manner as in Example 1 except that 8.4 parts by weight of BHT is used for the charge transport layer. A multilayer photoreceptor according to the present invention having a structure was prepared.

Example 9
A laminated type photoreceptor according to the present invention having a laminated structure in which a charge generation layer, a charge transport layer, and a surface protective layer are sequentially laminated on a conductive support in the same manner as in Example 1 except that no intermediate layer is provided. did.

(Comparative Example 1)
A laminated photoreceptor was prepared in the same manner as in Example 1 except that the diamine compound according to the present invention was not used.

(Comparative Example 2)
A laminated photoreceptor was produced in the same manner as in Example 1 except that hydroxyethyldibenzylamine (the compound described in JP-A-3-172852) was used instead of the diamine compound according to the present invention.

(Comparative Example 3)
A laminated photoreceptor in the same manner as in Example 1 except that a diamine compound represented by the following structural formula (5) (a compound described in JP-A-5-158258) was used instead of the diamine compound according to the present invention. Was made.

  For each of the photoreceptors of Examples 1 to 9 and Comparative Examples 1 to 3 manufactured as described above, (a) ozone gas resistance and (b) stability of electrical characteristics were evaluated as follows. c) A comprehensive determination of the photoreceptor performance was made.

(A) Ozone gas resistance [Evaluation by evaluation equipment]
Each evaluation apparatus evaluation photoreceptor of Examples 1 to 9 and Comparative Examples 1 to 3 (layer thickness of the charge transport layer: 15 μm) is mounted on a test copying machine, and the temperature is 25 ° C. and the relative humidity is 50%. In a normal temperature / normal humidity (N / N) environment, the surface potential V ₁ (V) of the photoconductor immediately after charging and the surface potential V ₂ (V) of the photoconductor 3 seconds after charging are measured. did. In the test copying machine, the surface potential of the photosensitive member in the image forming process is set inside a commercially available copying machine (trade name: AR-F330, manufactured by Sharp Corporation) equipped with a corona discharge charger as charging means for the photosensitive member. What provided the surface electrometer (brand name: CATE751, the Gentec company make) so that it could measure was used. The measured surface potential V ₁ (V) immediately after charging and the surface potential V ₂ (V) after 3 seconds from charging are substituted into the following formula (I) to calculate the charge retention ratio DD (%). was the initial charge retention rate DD _0.

Next, using an ozone generation / control device (trade name: OES-10A, manufactured by Directec Co., Ltd.), each photoconductor has an ozone concentration of about 7.5 ppm (the ozone concentration meter MODEL1200 (trade name) manufactured by Directec Co., Ltd.). Exposure to ozone for 20 hours in a sealed container adjusted to (confirmation). After exposure to ozone, each photoconductor was left in a room temperature / normal humidity (N / N) environment at a temperature of 25 ° C. and a relative humidity of 50% for 2 hours, and then the charge retention ratio DD (% ) And obtained as the charge retention ratio DD ₀₂ after ozone exposure.
The value obtained by subtracting the charge retention ratio DD ₀₂ after ozone exposure from the charge retention ratio before exposure to ozone, that is, the initial charge retention ratio DD ₀ , is obtained as a charge retention ratio change amount ΔDD (= DD ₀ -DD ₀₂ ). Was used as an evaluation index.

[Evaluation with actual machine]
Commercially available copying machines AR-F330 (Embodiments 1 to 9 and Comparative Examples 1 to 3) having a corona discharge charger as a charging means for the photoconductors for evaluation of actual machines (layer thickness of the charge transport layer: 28 μm). The product is mounted on a product name (Sharp Corporation), and a test image of a predetermined pattern is photographed on 50,000 sheets of recording paper in a normal temperature / normal humidity (N / N) environment at a temperature of 25 ° C. and a relative humidity of 50%. It was. The operation of the copying machine was stopped for 1 hour after the end of the 50,000 actual shots, and then a halftone image was copied on the recording paper, which was used as the first evaluation image. Next, a test image of a predetermined pattern is photographed on 50,000 sheets of recording paper again in an N / N environment at a temperature of 25 ° C. and a relative humidity of 50%, and the copying machine operates for one hour from the point when 50,000 sheets are photographed. Then, a halftone image was copied on the recording paper, and this was used as a second evaluation image.

  The formed first evaluation image and second evaluation image were visually observed, and the toner image was transferred from the portion of the photoconductor that was placed close to the corona discharge charger when the operation of the copying machine was stopped. The image quality of the portion of the recording paper corresponding to the portion was determined based on the degree of occurrence of image defects such as white spots and black bands, and used as an evaluation index for ozone gas resistance. The criteria for determining the image quality are as follows.

A: Excellent (no image defect occurred in any of the first evaluation image and the second evaluation image)
○: Good (although some image defects occur in one or both of the first evaluation image and the second evaluation image, they are negligible)
Δ: Acceptable (Some image defects have occurred in one or both of the first evaluation image and the second evaluation image, but there is no problem in practical use)
×: Impossible (A large number of image defects occur in one or both of the first evaluation image and the second evaluation image and cannot be used in practice)

The above-described value of the charge retention rate change ΔDD and the image quality determination result were combined to evaluate the ozone gas resistance of the photoreceptor. The evaluation criteria for ozone gas resistance are as follows.
A: Excellent (ΔDD is less than 4.0% and image quality is excellent (A))
○: Good (ΔDD is 4.0% or more and less than 7.0% and image quality is excellent (（), or ΔDD is less than 7.0% and image quality is good (◯))
Δ: No problem in actual use (ΔDD is less than 7.0% and image quality is acceptable (Δ))
×: Defect (ΔDD is 7.0% or more, or image quality is not possible (×))

(B) Stability of electrical characteristics Each of the actual machine evaluation photoreceptors of Examples 1 to 9 and Comparative Examples 1 to 3 (layer thickness of charge transport layer: 28 μm) is mounted on a test copying machine, and the temperature is 5 ° C. Under a low temperature / low humidity (L / L) environment with a relative humidity of 20% and under a high temperature / high humidity (H / H) environment with a temperature of 35 ° C and a relative humidity of 85% In the following environment, the stability of the electrical characteristics was evaluated as follows. In the test copying machine, the surface potential of the photosensitive member in the image forming process is set inside a commercially available copying machine (trade name: AR-F330, manufactured by Sharp Corporation) equipped with a corona discharge charger as charging means for the photosensitive member. What provided the surface electrometer (brand name: CATE751, the Gentec company make) so that it could measure was used. The copying machine AR-F330 is a negatively charged image forming apparatus that performs electrophotographic process by negatively charging the surface of the photoreceptor.

Using the test copying machine on which each of the photoconductors of Examples 1 to 9 and Comparative Examples 1 to 3 is mounted, the surface potential of the photoconductor immediately after the charging operation by the charger is measured as a charging potential V0 (V). It was the charging potential V0 ₁ early. The measured surface potential of the photosensitive member immediately after subjected to exposure by a laser beam as a residual potential Vr (V), which was used as the initial residual potential Vr _1.
Then, after copying successively the test image of a predetermined pattern on the recording paper 30 million copies, the initial and in the same manner by measuring the charge potential V0 and residual potential Vr, the charge potential V0 ₂ and after repeated use of these The residual potential Vr ₂ after repeated use was set. The absolute value of the difference between the initial charging potential V0 ₁ and the charging potential V0 ₂ after repeated use was determined as a charging potential change amount ΔV0 (= | V0 ₁ −V0 ₂ |). Further, the absolute value of the difference between the initial residual potential Vr ₁ and the residual potential Vr ₂ after repeated use was determined as a residual potential change amount ΔVr (= | Vr ₁ −Vr ₂ |). The stability of the electrical characteristics was evaluated using the charging potential change amount ΔV0 and the residual potential change amount ΔVr as evaluation indexes.

(Evaluation criteria for stability of electrical characteristics under L / L environment are as follows)
A: Excellent (ΔV0 is 35V or less and ΔVr is 55V or less)
○: Good (ΔV0 is 35V or less and ΔVr exceeds 55V and 80V or less, or ΔV0 exceeds 35V and 75V or less and ΔVr is 55V or less)
Δ: No problem in actual use. ΔV0 exceeds 35V and 75V or less, and ΔVr exceeds 55V and 80V or less)
X: Defect (ΔV0 exceeds 75V or ΔVr exceeds 80V)

The evaluation criteria for the stability of the electrical characteristics in the H / H environment are as follows.
A: Excellent (ΔV0 is 15V or less and ΔVr is 105V or less)
○: Good (ΔV0 is 15V or less and ΔVr exceeds 105V and 125V or less, or ΔV0 exceeds 15V and 30V or less and ΔVr is 105V or less)
Δ: No problem in actual use (ΔV0 exceeds 15V and 30V or less, and ΔVr exceeds 105V and 125V or less)
X: Defect (ΔV0 exceeds 30V or ΔVr exceeds 125V)

In addition, the evaluation result in the L / L environment and the evaluation result in the H / H environment were combined to perform a comprehensive evaluation of the stability of the electrical characteristics. The evaluation criteria for the comprehensive evaluation of the stability of the electrical characteristics are as follows.
A: Excellent (L / L environment and H / H environment are both excellent (A))
○: Good (in either L / L environment or H / H environment is good (◯) and the other is excellent (◎) or good (○))
Δ: No problem in actual use (There is no problem in actual use in either L / L environment or H / H environment (△) and the other is not defective (x))
X: Defect) Either one or both of L / L environment and H / H environment is defective (X))

(C) Comprehensive Judgment of Photoreceptor Performance A comprehensive judgment of the photoreceptor performance was made by combining the evaluation result of ozone gas resistance and the comprehensive evaluation result of stability of electrical characteristics. (The criteria for comprehensive judgment are as follows)
A: Excellent (ozone gas resistance and electrical property stability are both excellent (A))
○: Good (either ozone gas resistance or electrical property stability is good (◯) and the other is excellent (◎) or good (○))
△: No problem in actual use (either ozone gas resistance or electrical property stability is not a problem in actual use (△) and the other is not defective (x))
X: Defect (one or both of ozone gas resistance and electrical property stability are unsatisfactory (x))
The above evaluation results are shown in Table 2.

From the comparison between Examples 1 to 4 and Comparative Example 1, the photoreceptors of Examples 1 to 4 containing the diamine compound according to the present invention in the surface protective layer are compared with the photoreceptors of Comparative Examples 1 to 3 not containing them. Thus, the ozone gas resistance and the stability of the electrical characteristics are excellent, and it can be seen that even when used repeatedly, the electrical characteristics are good.
Further, from Examples 5 and 6, if the ratio A / B between the weight A of the diamine according to the present invention and the weight B of the binder resin in the surface protective layer is 0.1 / 100 or more and 30/100 or less, a good effect is obtained. You can see that

Further, from Examples 7 and 8, the ratio C / D between the weight C of the antioxidant in the charge transport layer and the total weight D of the weight of the charge transport material and the binder resin is determined by the diamine according to the present invention in the surface protective layer. It can be seen that a good effect is exhibited when the ratio is lower than the ratio A / B of the weight A of the resin and the weight B of the binder resin.
Further, it can be seen from Example 9 that by having an intermediate layer between the conductive support and the photosensitive layer, it is difficult to cause image defects due to minute black spots or fog caused by injection of charges from the conductive support.

  From a comparison between Example 1 and Comparative Examples 2 and 3, a known amine-based or diamine-based material proposed for the same purpose as the present invention has a difference in effect when evaluated up to image quality. It clearly shows that the photoreceptor of Example 1 using the diamine compound of the present invention is superior.

  In addition, the diamine-based material is within an acceptable range in comparison with the diamine-based compound of the present invention in terms of image quality, but the deterioration in terms of repeated electrical characteristics due to the influence of inorganic metal impurities that may be caused by the production method. It turns out that there is a significant problem.

  As described above, by including the diamine compound represented by the general formula (1) in the surface protective layer, it has excellent electrical characteristics such as chargeability and responsiveness, and is excellent in ozone gas resistance and can be used repeatedly. It was possible to obtain an electrophotographic photoreceptor excellent in property stability in which the above-described good electrical properties were not deteriorated.

FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of a single layer type photoreceptor of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of a single layer type photoreceptor of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of the multilayer photoconductor of the present invention. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of the multilayer photoconductor of the present invention. 1 is a schematic side view illustrating a configuration of an image forming apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive support body 2 Single layer type photosensitive layer 3 Charge generation layer 4 Charge transport layer 5 Surface protective layer 6 Intermediate layer 7 Laminated type photosensitive layer 11-18, 21 Photoconductor

20 Image forming apparatus 22 Axis of rotation 23, 29 Arrow 24 Charging means (charger)
24a Charging roller 24b Bias power supply 25 Developing means (developer)
25a Developing roller 25b Casing 26 Transfer device 27 Cleaner 27a Cleaning blade 27b Recovery casing 28 Exposure means 28a Light 30 Transfer paper 31 Fixing device 31a Heating roller 31b Pressure roller

Claims (8)

On a conductive support made of a conductive material, a single-layer type photosensitive layer containing a charge generating substance and a charge transporting substance or a charge generating layer containing a charge generating substance and a charge transporting layer containing a charge transporting substance An electrophotographic photosensitive member in which a laminated photosensitive layer laminated in this order and a surface protective layer are laminated in this order, the surface protective layer,
General formula (1):

(In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ are the same or different, and an aryl group which may have a substituent or a cycloalkyl group which may have a substituent) , A heteroatom-containing cycloalkyl group which may have a substituent or a monovalent heterocyclic residue which may have a substituent; Y ¹ , Y ² , Y ³ and Y ⁴ may be the same or different A chain-like alkylene group which may have a substituent)
An electrophotographic photoreceptor comprising a diamine compound represented by the formula: The diamine compound is a sub-formula (2):

(In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ have the same meanings as in the general formula (1); n, m, l and p are the same or different and represent 1 to 3 Is an integer)
The electrophotographic photosensitive member according to claim 1, which is represented by: The diamine compound is a sub-formula (3):

(In the formula, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ and Ar ⁶ have the same meanings as those in the general formula (1)).
The electrophotographic photosensitive member according to claim 2, which is represented by:   The surface protective layer contains a binder resin, and the ratio A / B between the weight A of the diamine compound and the weight B of the binder resin is 0.1 / 100 or more and 30/100 or less. The electrophotographic photosensitive member according to any one of the above.   The charge transport layer of the single layer type photosensitive layer or the multilayer type photosensitive layer contains an antioxidant and a binder resin, and the total of the weight C of the antioxidant, the weight of the charge transport material, and the binder resin. The electrophotographic photosensitive member according to claim 4, wherein a ratio C / D to the weight D is lower than the ratio A / B.   The electrophotographic photosensitive member according to claim 1, further comprising an intermediate layer between the conductive support and the single-layer type photosensitive layer or the laminated photosensitive layer.   An electrophotographic photosensitive member according to any one of claims 1 to 6, a charging unit for charging the electrophotographic photosensitive member, an exposure unit for exposing the charged electrophotographic photosensitive member, and exposure An image forming apparatus comprising: a developing unit that develops the electrostatic latent image formed by the step.   The image forming apparatus according to claim 7, wherein the charging unit is a contact charging unit.

Images