JP2010197964A - Electrophotographic photoreceptor, and image forming apparatus provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoreceptor which is hardly changed in sensitivity even at low temperature/low humidity and can attain satisfactory image characteristics, and an image forming apparatus provided with the same. <P>SOLUTION: The electrophotographic photoreceptor includes an intermediate layer provided between a conductive support and a photosensitive layer. The intermediate layer contains at least metal oxide fine particles and a binder resin. The binder resin is a polyamide resin that is a condensate of alicyclic diamine with higher aliphatic di- or tricarboxylic acid or an alkyl ester thereof, or with a mixture thereof. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes an intermediate layer containing a polyamide resin having a specific structure and metal oxide fine particles, and can realize good image characteristics with little change in sensitivity even at low temperature and low humidity (also referred to as “photoreceptor”). And an image forming apparatus including the same.

2. Description of the Related Art An electrophotographic image forming apparatus (also referred to as “electrophotographic apparatus”) that forms an image using electrophotographic technology is widely used in copying machines, printers, facsimile machines, and the like.
A photoreceptor used in an electrophotographic process is configured by laminating a photosensitive layer containing a photoconductive material on a conductive support.

  Conventionally, a photoconductor (also referred to as “inorganic photoconductor”) having a photosensitive layer mainly composed of an inorganic photoconductive material has been widely used. However, it is resistant to heat resistance, storage stability, human body and environment. It has defects in any of the aspects of toxicity, sensitivity, durability, occurrence of image defects, productivity, manufacturing cost, etc., and satisfactory products are not obtained in all points.

  On the other hand, research and development of a photoreceptor (also referred to as “organic photoreceptor”) having a photosensitive layer mainly composed of an organic photoconductive material has progressed, and now it occupies the mainstream of photoreceptors.

  Organic photoreceptors have some problems in sensitivity, durability, and environmental stability, but have many advantages over inorganic photoreceptors in terms of toxicity, manufacturing cost, and freedom of material design. Have. For example, an organic photoreceptor can form a photosensitive layer by an easy and inexpensive method typified by a dip coating method.

  As an organic photoreceptor, a single layer type photosensitive material in which a charge generation material and a charge transport material (also referred to as “charge transfer material”) are dispersed in a binder resin (also referred to as “binder resin” or “binder resin”). Layers are stacked on a conductive support, and a charge generation layer in which a charge generation material is dispersed in a binder resin and a charge transport layer in which a charge transport material is dispersed in a binder resin are formed in this order or in reverse order. A configuration in which the laminated photosensitive layer or the reverse laminated photosensitive layer is laminated on a conductive support has been proposed. Among these, the function-separated type photoconductor having a laminated type photosensitive layer and a reverse laminated type photosensitive layer is excellent in electrophotographic characteristics and durability, has a high degree of freedom in material selection, and can be designed in various ways. Widely used.

  When the photosensitive layer is applied and formed directly on the conductive support in the production of an organic photoreceptor, the photosensitive layer is easily affected by the surface of the conductive support, and it is difficult to form a uniform and uniform film. For this reason, there has been a problem that film thickness unevenness occurs and causes various image defects and density unevenness.

  In addition, in an organic photoreceptor having a laminated photosensitive layer, since the conductive support and the charge generation layer are in direct contact with each other, when an electric field is applied by charging, a charge is generated in a part of the charge generation material. However, when the charge generating substance is present nearby, the potential is locally lowered, and there is a problem that fogging or the like occurs on the white paper or the gray portion in the reversal development. This was particularly remarkable in a high temperature and high humidity environment.

  As a countermeasure against the above problems, it is conventionally known that it is effective to provide a resin layer called an intermediate layer (also referred to as “undercoat layer”) between a conductive support and a photosensitive layer. For example, a layer in which an alcohol-soluble polyamide resin is applied and dried is proposed as an intermediate layer.

  However, even if such an intermediate layer is provided, good electrical characteristics and image quality can be obtained in a normal environment, but these alcohol-soluble resins have a large resistance change due to the environment such as temperature and humidity. In addition, there is a problem that defects such as black spots, memory, and density unevenness occur on the image.

Therefore, a layer containing titanium oxide as an intermediate layer has also been proposed.
Recently, a photoreceptor using a polyamide resin having a low water absorption rate (Japanese Patent Application Laid-Open No. 2003-287914: Patent Document 1, Patent No. 2841720: Patent Document 2) has also been proposed.
Furthermore, various polyamide resins have been proposed as resins with little environmental change (Japanese Patent Laid-Open No. 2006-208474: Patent Document 3, Japanese Patent Laid-Open No. 2007-178660: Patent Document 4).

JP 2003-287914 A Japanese Patent No. 2841720 JP 2006-208474 A JP 2007-178660 A

However, a polyamide resin having a small water absorption rate and having a small environmental change as an intermediate layer has poor solubility in a solvent and is likely to cause coating unevenness, or dispersibility is likely to cause white turbidity. There are drawbacks such as large accumulation of residual potential below.
Accordingly, it is an object of the present invention to provide a photoconductor capable of realizing good image characteristics with little change in sensitivity even at low temperature / low humidity, and an image forming apparatus including the photoconductor.

  As a result of intensive studies to solve the above-described problems, the present inventors have found that an intermediate layer containing a specific polyamide resin improves the charging characteristics and sensitivity characteristics of the photosensitive member against humidity, and the fogging. It has been found that image defects such as black spots can be prevented without causing the occurrence of image defects, and the present invention has been completed.

Thus, according to the present invention, an intermediate layer is provided between the conductive support and the photosensitive layer, and the intermediate layer contains at least metal oxide fine particles and a binder resin, and the binder resin is an alicyclic ring. An electrophotographic photosensitive member is provided which is a polyamide resin which is a condensate of a formula diamine and a higher aliphatic di- or tricarboxylic acid or an alkyl ester thereof or a mixture thereof.
According to the present invention, the electrophotographic photosensitive member described above, a charging unit that charges the electrophotographic photosensitive member, and an exposing unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image; An image comprising: a developing unit that develops and visualizes the electrostatic latent image formed by exposure; and a transfer unit that transfers the image visualized by the development onto a recording medium. A forming apparatus is provided.

According to the present invention, it is possible to provide a photoconductor capable of realizing good image characteristics with little change in sensitivity even at low temperature / low humidity, and an image forming apparatus including the photoconductor.
In addition, the coating liquid for coating and forming the intermediate layer of the photoreceptor of the present invention can maintain a desired dispersion state for a long period of time, and can form a coating film without coating unevenness even after long-term storage. it can.

FIG. 2 is a schematic cross-sectional view showing a configuration of a main part of the electrophotographic photosensitive member of the present invention. FIG. 2 is a schematic cross-sectional view showing a configuration of a main part of the electrophotographic photosensitive member of the present invention. 1 is a schematic side view illustrating a configuration of an image forming apparatus of the present invention.

で表される、１−アミノ−３−アミノメチル−３,５,５−トリメチルシクロヘキサン、１−アミノ−３−アミノメチル−２,５,６−トリメチルシクロヘキサンまたは１−アミノ−４−(４'−アミノシクロヘキシルメチル)シクロヘキサンであることを特徴とする。
なかでも、１−アミノ−３−アミノメチル−３,５,５−トリメチルシクロヘキサンが好ましい。 In the electrophotographic photoreceptor according to the present invention, the alicyclic diamine is a cyclohexylene-based diamine, and has the following chemical structural formula:

1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 1-amino-3-aminomethyl-2,5,6-trimethylcyclohexane or 1-amino-4- (4 ′) -Aminocyclohexylmethyl) cyclohexane.
Of these, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane is preferable.

  In addition to the above alicyclic diamines, 1,2-diaminocyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, 2′-aminomethylcyclohexylmethylamine, 3′-aminomethylcyclohexylmethylamine, 4'-aminomethylcyclohexylmethylamine, 2'-aminoethylcyclohexylethylamine, 3'-aminoethylcyclohexylethylamine, 4'-aminoethylcyclohexylethylamine, 2'-aminopropylcyclohexylpropylamine, 3'-aminopropylcyclohexylpropyl Examples include cyclohexylene-based diamines such as amine, 4′-aminopropylcyclohexylpropylamine, and bicyclohexanediamine.

  In the electrophotographic photoreceptor according to the present invention, the higher aliphatic di- or tricarboxylic acid is a two- or three-molecule addition reaction product of oleic acid, linoleic acid, an alkyl ester thereof, or a mixture thereof. To do.

  The electrophotographic photoreceptor according to the present invention is characterized in that the metal oxide fine particles are titanium oxide.

  In the electrophotographic photoreceptor according to the present invention, the metal oxide particles are titanium oxide particles having a number average primary particle diameter of 30 to 50 nm.

  The electrophotographic photoreceptor according to the present invention is characterized in that the polyamide resin has a number average molecular weight of 5,000 to 80,000.

  The electrophotographic photoreceptor according to the present invention is characterized in that the metal oxide particles are contained in a proportion of 50 to 1000 parts by weight with respect to 100 parts by weight of the polyamide resin.

  In the electrophotographic photoreceptor according to the present invention, the photosensitive layer is a laminated photosensitive layer in which a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material are laminated in this order. It is characterized by being.

The binder resin in the intermediate layer of the electrophotographic photoreceptor according to the present invention contains at least a specific polyamide resin obtained by adding a cyclohexylene-based diamine compound and a higher aliphatic di- or tricarboxylic acid or an alkyl ester thereof or a mixture thereof. To do.
The term “higher aliphatic” used in the present invention means an aliphatic having 10 or more carbon atoms.
The term “alkyl ester” used in the present invention means an ester of the above higher fatty acid and an alcohol having 1 to 4 carbon atoms.
That is, the term “alkyl ester” used in the present invention means methyl ester, ethyl ester, propyl ester, isopropyl ester, n-butyl ester or t-butyl ester.

  The term “higher aliphatic di- or tricarboxylic acid” used in the present invention is an unsaturated decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, heptadecenoic acid, Fatty acids having an unsaturated bond such as octadecenoic acid (oleic acid), nonadedecenoic acid, eicosenoic acid, or decadienoic acid, undecadienoic acid, dodecadienoic acid, tridecadienoic acid, tetradecadienoic acid, pentadecadienoic acid, hexadecadiene Obtained by subjecting higher fatty acids having unsaturated bonds at two positions such as acid, heptadecadienoic acid, octadecadienoic acid (linoleic acid), nonadecadienoic acid, eicosadienoic acid, or their esters alone or a mixture of two types to an addition reaction The same or different molecules It means the dicarboxylic acid or tricarboxylic acids or their hydrogenated products adducts.

  Among these, dicarboxylic acids or tricarboxylic acids, or hydrogenated products thereof, which are adducts between the same molecule or different molecules obtained by subjecting oleic acid or linoleic acid or a mixture thereof or an alkyl ester thereof to an addition reaction. preferable.

  Examples of commercially available dicarboxylic acids include Halidimer 200 and 300 (manufactured by Harima Chemicals), Empor 1022 (manufactured by Cognis), and the like. Furthermore, hydrogenated dicarboxylic acid can also be used, and examples of commercially available hydrogenated dicarboxylic acid include Preball 1009 (manufactured by Croda).

  The above higher aliphatic di- or tricarboxylic acid or alkyl ester thereof can be generally produced by an addition reaction using the above higher unsaturated fatty acid or ester thereof. Examples of the addition reaction catalyst include activated clays such as liquid or solid Lewis acid, Bronsted acid and montmorillonite, bentonite, hectorite and halloysite.

  When the above-mentioned higher aliphatic di- or tricarboxylic acid or alkyl ester thereof has an unsaturated bond, it can be produced by hydrogenation. The higher fatty acid dicarboxylic acid may be mixed with the higher fatty acid tricarboxylic acid which effectively acts to improve the flexibility of the resin.

In addition, an appropriate amount of other higher saturated fatty acid lower alkyl esters can be added to the higher aliphatic di- or tricarboxylic acids or their alkyl esters and used in combination.
That is, in combination with methyl, ethyl, isopropyl or t-butyl esters such as decanoic acid, hedecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, nonadecanoic acid, eicosanoic acid, etc. Also good.

In addition, other dicarboxylic acids can be added to the higher aliphatic di- or tricarboxylic acids or their alkyl esters.
That is, as the dicarboxylic acid, a dicarboxylic acid having 2 to 22 carbon atoms, specifically, oxalic acid, malonic acid, (anhydrous) succinic acid, (anhydrous) maleic acid, glutaric acid, adipic acid, vimelic acid, suberic acid, Combined use of azelaic acid, zepacic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, 1,3- or 1,4-cyclohexanedicarboxylic acid, 1,18-octadecanedicarboxylic acid, 1,16-hexadecanedicarboxylic acid May be.

The polyamide resin of the present invention can be obtained by subjecting the above-mentioned higher aliphatic di- or tricarboxylic acid or their alkyl ester to the above cyclohexylene-based diamine derivative.
Examples of cyclohexylene-based diamine derivatives include 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 1-amino-3-aminomethyl-2,5,6-trimethylcyclohexane or 1-amino-4- (4'-Aminocyclohexylmethyl) cyclohexane can be used, but 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane is preferred.

  Moreover, ethylenediamine, diaminopropane, diaminobutane, diaminopentane, hexamethylenediamine, octanediamine, nonanediamine, decanediamine, dodecanediamine, xylenediamine, phenylenediamine, toluylenediamine, diaminodiphenylmethane, diaminodiphenyl ether, Diaminobenzophenone, 1,3-bis (4-aminophenoxy) benzene or the like may be used alone or in combination of two or more.

The polyamide resin used in the present invention can be obtained, for example, by a polyamide synthesis method described in JP-B-55-38380.
The production method of the polyamide resin is not particularly limited, and a normal polyamide polycondensation method, a melt polymerization method, a solution polymerization method, an interfacial polymerization method and the like can be appropriately applied. In the polymerization, a monobasic acid such as acetic acid or benzoic acid, or a monoacid base such as hexylamine or aniline may be used as a molecular regulator.

This polycondensation reaction is performed according to a conventional method. That is, by heating a solution in which the higher aliphatic di- or tricarboxylic acid or their alkyl ester and the cyclohexylene-based diamine derivative are mixed in an equivalent amount or a suitable ratio, the molecular weight is increased while removing water and alcohol. It is better to do it.
As reaction conditions, the reaction temperature is 100 to 300 ° C, preferably 120 to 230 ° C, more preferably 130 to 200 ° C.

The reaction time cannot be determined because it is performed until the condensation polymerization is completed, but it is usually within 10 hours.
In order to perform the present polycondensation reaction, the di- or tricarboxylic acid or ester thereof and the cyclohexylene-based diamine derivative are mixed in an equivalent amount or a suitable ratio before heating. At this time, methanol, ethanol, isopropanol or water is mixed. It is preferable to dissolve and mix the reaction raw materials.

Further, before heating, the solution may be decompressed and an inert gas may be introduced and kept in an inert gas atmosphere.
The dehydration or dealcoholization reaction by heating is usually performed under normal pressure while introducing a small amount of inert gas, but may be performed in a reduced pressure system or a pressurized system.
When the above condensation polymerization reaction proceeds, the reaction solution gradually increases in viscosity. Therefore, it is preferable to keep the temperature at the melting temperature of the condensation polymerization product or higher.

  The binder resin used in the intermediate layer of the photoreceptor of the present invention is a polyamide resin which is a condensate of a cyclohexylene-based diamine derivative and a higher aliphatic di- or tricarboxylic acid or an alkyl ester thereof or a mixture thereof. The resin may contain ε-caprolactam, 4,4′-diamino-dicyclohexylmethane, 1,6-hexamethylenediamine, adipic acid and the like as other structural units, but the proportion is preferably 50 mol% or less. .

The number average molecular weight of the polyamide resin of the present invention is preferably from 5,000 to 80,000, particularly preferably from 10,000 to 60,000.
When the number average molecular weight of the polyamide resin is less than 5,000, the uniformity of the film thickness of the intermediate layer is deteriorated, and the effects of the present invention are not sufficiently exhibited. In addition, when the number average molecular weight of the polyamide resin exceeds 80,000, the solubility of the resin in the solvent tends to be lowered, and an aggregated resin is likely to be generated in the intermediate layer, and image defects such as black spots are likely to occur. .

  In the present invention, the number average molecular weight was measured as follows. Using a GPC apparatus (trade name: HLC-8220 GPC, manufactured by Tosoh Corporation), at a temperature of 40 ° C., a 0.25 wt% hexafluoroisopropanol solution of the sample is used as the sample solution, and the injection amount of the sample solution is 100 mL, and the molecular weight A distribution curve was determined. The molecular weight at the peak of the obtained molecular weight distribution curve was determined as the peak top molecular weight. Moreover, the number average molecular weight Mn was calculated | required from the obtained molecular weight distribution curve. The molecular weight calibration curve was prepared using standard polystyrene.

  The intermediate layer of the photoreceptor of the present invention contains titanium oxide particles as metal oxide fine particles. The metal oxide fine particles may be coated on the surface with alumina or silica in order to improve the dispersion stability.

The crystal form of titanium oxide includes anatase type, rutile type, and amorphous type. In the present invention, the crystal type of the titanium oxide particles may be any, and may be a mixture of two or more, but the stability of physical properties The rutile type is particularly preferable from the viewpoint of properties.
Further, the shape of the titanium oxide particles includes dendrites, needles, and granules. In the present invention, any shape of the titanium oxide particles may be used, but in terms of achieving both film strength and electrical characteristics, Is particularly preferred.

The number average primary particle size of the titanium oxide particles is preferably 30 to 50 nm.
If the number average primary particle diameter of the titanium oxide particles is less than 30 nm, the dispersion efficiency of the titanium oxide is lowered, and minute black spots are easily generated in the image. Moreover, even if the number average primary particle diameter of the titanium oxide particles exceeds 50 nm, the dispersibility of the titanium oxide is lowered, and the initial sensitivity may be easily lowered in a low temperature and low humidity environment.

  As such commercially available titanium oxide particles, for example, trade name: MT-500SA (average primary particle size: 35 nm) manufactured by Teika Co., Ltd. may be mentioned.

The intermediate layer of the photoreceptor of the present invention mainly contains titanium oxide particles and a binder resin, and may contain additives such as an antioxidant and a conductive agent as necessary.
The intermediate layer is prepared, for example, by dissolving or dispersing the titanium oxide particles of the present invention, the polyamide resin of the present invention and, if necessary, an additive in an organic solvent to prepare a coating solution for forming an intermediate layer. It can form by apply | coating to the surface of a support body and drying and removing an organic solvent.

Specifically, a coating solution for forming an intermediate layer can be prepared by dissolving the polyamide resin of the present invention in an organic solvent and adding the titanium oxide particles of the present invention to the resulting solution and dispersing it.
In order to disperse the titanium oxide particles in the solution, treatment may be performed using a ball mill, a sand mill, a roll mill, a paint shaker, an attritor, an ultrasonic disperser, or the like.

  The content of titanium oxide in the intermediate layer is preferably 50 to 1000 parts by weight, more preferably 70 to 800 parts by weight, and more preferably 100 to 500 parts by weight with respect to 100 parts by weight of the polyamide resin as the binder resin. Is particularly preferred.

  If the content of titanium oxide in the intermediate layer is within the above range, the balance between the dispersibility of titanium oxide and the electrical insulating property is improved, and the occurrence of fogging under high temperature and high humidity can be further reduced. it can.

  Examples of the organic solvent include lower alcohols such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, tert-butanol and sec-butanol. Among these, methanol and ethanol are particularly preferable in terms of the solubility of the polyamide resin and the coating property of the prepared coating solution.

In the coating solution for forming the intermediate layer, the lower alcohol solvent is preferably 30 to 100% by weight, more preferably 40 to 100% by weight, and 50 to 100% by weight in all the solvents. Particularly preferred.
In preparation of the coating solution for forming the intermediate layer, toluene, methylene chloride, cyclohexanone, tetrahydrofuran or the like may be used in combination as a cosolvent for adjusting the solvent evaporation rate.

The cosolvent is about 5 to 50% by weight of the organic solvent.
The coating method for the intermediate layer forming coating solution may be appropriately selected in consideration of the physical properties and productivity of the coating solution, for example, dip coating method, spray method, nozzle method, bar coating method, Examples thereof include a roll coating method, a blade method, a ring method, and a dip coating method.
Among these coating methods, the dip coating method is a method of forming a layer on the surface of the substrate by immersing the substrate in a coating tank filled with a coating solution and then pulling it up at a constant speed or a speed that changes sequentially. Since it is relatively simple and excellent in terms of productivity and cost, it can be suitably used for the production of a photoreceptor. In order to stabilize the dispersibility of the coating liquid, the apparatus used for the dip coating method may be provided with a coating liquid dispersing apparatus represented by an ultrasonic generator.

  From the above, the intermediate layer of the photoreceptor of the present invention is preferably formed by a coating method using a coating solution in which titanium oxide particles and polyamide resin are dissolved or dispersed in a solvent composed of a lower alcohol.

Although it will not specifically limit if the temperature in the drying process of a coating film is the temperature which can remove the used organic solvent, 50-140 degreeC is suitable and 80-130 degreeC is especially preferable.
When the drying temperature is less than 50 ° C., the drying time may be long. On the other hand, if the drying temperature exceeds 140 ° C., the electrical characteristics during repeated use of the photoreceptor may deteriorate and the resulting image may deteriorate.

The temperature conditions in the production of such a photosensitive layer are common not only in the intermediate layer but also in the formation of layers such as a photosensitive layer described later and other processes.
If the thickness of the intermediate layer is too thin, the effect on local charging failure will not be sufficient, and if it is too thick, the residual potential will increase or the adhesive strength between the conductive support and the photosensitive layer will decrease. . Therefore, the film thickness of the intermediate layer is preferably 0.1 to 10 μm, and more preferably 0.3 to 5 μm.

Next, the structure of the photoreceptor of the present invention will be described in detail.
1 and 2 are schematic cross-sectional views showing the structure of the main part of the photoreceptor of the present invention.
In the photoreceptor 20b of FIG. 1, an intermediate layer 14b, a charge generation layer 11b, and a charge transport layer 12b are formed in this order on a conductive support 13b.
In the photoconductor 20d in FIG. 2, an intermediate layer 14d, a charge generation layer 11d, a charge transport layer 12d, and a surface protective layer 15d are formed in this order on a conductive support 13d.

The photosensitive layer of the photoreceptor of the present invention includes a single-layer type photosensitive layer containing a charge generation material and a charge transport material, and a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material. Any of a laminated photosensitive layer laminated in order, a reverse laminated photosensitive layer in which a charge generating layer containing at least a charge generating substance and a charge transporting layer containing a charge transporting substance are laminated in reverse order may be used. From the viewpoint of abrasion resistance, a laminated photosensitive layer as shown in FIGS. 1 and 2 is particularly preferable.
The structure other than the intermediate layer in the photoreceptor of the present invention will be described.

[Conductive supports 13b and 13d]
The constituent materials of the conductive supports 13b and 13d in the photosensitive layers 20b and 20d are not particularly limited as long as they have a function as an electrode of the multilayer photoreceptor 1 and a function as a support member, and are materials used in this field. .
Specifically, metallic materials such as aluminum, aluminum alloys, copper, zinc, stainless steel, and titanium: supports made of polymer materials such as polyethylene terephthalate, polyamide, polyester, polyoxymethylene, polystyrene, hard paper, glass, etc. Examples include those obtained by laminating a metal foil on the surface, those obtained by vapor-depositing a metal material, and those obtained by evaporating or applying a layer of a conductive compound such as a conductive polymer, tin oxide, or indium oxide.

The shape of the conductive supports 13b and 13d is not limited to a cylindrical shape (drum shape) as shown in FIG. 3, and may be a sheet shape, a columnar shape, an endless belt shape, or the like.
If necessary, the surface of the conductive support is subjected to irregular reflection treatment such as anodizing film treatment, surface treatment with chemicals, hot water, coloring treatment, and surface roughening within a range that does not affect the image quality. May be given.

  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.

[Charge generation layers 11b and 11d]
The charge generation layer contains a charge generation material that generates charges by absorbing light such as semiconductor laser light.
Substances effective as a charge generating substance include azo pigments such as monoazo pigments, bisazo pigments and trisazo pigments; indigo pigments such as indigo and thioindigo; perylene pigments such as perylene imide and perylene anhydride; anthraquinone and Polycyclic quinone pigments such as pyrenequinone; metal phthalocyanines such as oxotitanium phthalocyanine and phthalocyanine pigments such as metal-free phthalocyanine; organic photoconductive materials such as squarylium dyes, pyrylium salts, thiopyrylium salts, triphenylmethane dyes; and selenium Inorganic photoconductive materials such as amorphous silicon and the like can be used, and materials having sensitivity in the exposure wavelength region can be appropriately selected and used. These charge generation materials can be used alone or in combination of two or more.

  In order to improve the function of the charge generation material, triphenylmethane dyes such as methyl violet, crystal violet, knight blue and victoria blue, erythrosine, rhodamine B, rhodamine 3R, acridine orange and frappeosin Sensitizing dyes such as acridine 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 or thiopyrylium salt dyes They can be used in combination.

The ratio of use of the sensitizing dye is not particularly limited, but is preferably 10 parts by weight or less, particularly preferably 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the charge generating material.
The charge generation layer may contain a binder resin for the purpose of improving the binding property.

  As the binder resin, a resin having a binding property used in this field can be used, and a binder resin having excellent compatibility with the charge generation material is preferable.

  Specifically, polyester resin, polystyrene resin, polyurethane resin, phenol resin, alkyd resin, melamine resin, epoxy resin, silicone resin, acrylic resin, methacrylic resin, polycarbonate resin, polyarylate resin, phenoxy resin, polyvinyl butyral resin, polyvinyl Formal resins, copolymer resins containing two or more of the repeating units constituting these resins, and the like can be mentioned. Examples of the copolymer resin include insulating resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, and acrylonitrile-styrene copolymer resin. The binder resin is not limited to these, and a resin generally used in this field can be used as the binder resin. These binder resins can be used alone or in combination of two or more.

  The use ratio of the binder resin is not particularly limited, but is about 0.5 to 2.0 parts by weight with respect to 100 parts by weight of the charge generation material.

  The charge generation layer is selected from hole transport materials, electron transport materials, antioxidants, ultraviolet absorbers, dispersion stabilizers, sensitizers, leveling agents, plasticizers, fine particles of inorganic compounds or organic compounds, as necessary. An appropriate amount of one or more of them may be included.

The charge generation layer can be formed by a known dry method and wet method.
Examples of the dry method include a method of vacuum-depositing a charge generating material on the surface of an intermediate layer formed on a conductive support.
As a wet method, for example, a charge generation material and, if necessary, a binder resin are dissolved or dispersed in an appropriate organic solvent to prepare a coating solution for forming a charge generation layer, and this coating solution is formed on a conductive support. The method of apply | coating to the surface of the intermediate | middle layer made and then drying and removing an organic solvent is mentioned.

  Examples of the solvent used in the coating solution for the charge generation layer include halogenated hydrocarbons such as dichloromethane and dichloroethane; ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; tetrahydrofuran (THF) , Ethers such as dioxane; alkyl ethers of ethylene glycol such as 1,2-dimethoxyethane; aromatic hydrocarbons such as benzene, toluene and xylene; N, N-dimethylformamide, N, N-dimethylacetamide and the like Examples include aprotic polar solvents. Among these solvents, non-halogen organic solvents are preferably used in consideration of the global environment. These solvents can be used alone or in combination of two or more.

  Prior to dissolving or dispersing the charge generation material in the solvent, the charge generation material may be previously pulverized by a pulverizer. Examples of the pulverizer used for the pulverization treatment include a ball mill, a sand mill, an attritor, a vibration mill, and an ultrasonic disperser.

  Dispersers such as paint shakers, ball mills, and sand mills can be used to dissolve or disperse the charge generating material in the solvent. 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.

Other steps and conditions are in accordance with the formation of the intermediate layer.
The thickness of the charge generation layer is not particularly limited, but is preferably 0.05 to 5 μm, particularly preferably 0.1 to 1 μm.
If the thickness of the charge generation layer is less than 0.05 μm, the light absorption efficiency is lowered, and the sensitivity of the photoreceptor may be lowered. On the other hand, if the thickness of the charge generation layer exceeds 5 μm, the charge transfer inside the charge generation layer becomes a rate-determining step in the process of erasing the charge on the surface of the photosensitive layer, which may reduce the sensitivity of the photoreceptor.

[Charge transport layers 12b, 12d]
The charge transport layer has a function of transporting charges generated in the charge generation layer to the surface of the photoreceptor.
The charge transport layer contains at least a charge transport material and a binder resin.

As the charge transport material, high molecular compounds such as polyvinyl carbazole, polyvinyl pyrene, and polyacenaphthylene, or low molecular compounds such as various pyrazoline derivatives, oxazole derivatives, hydrazone derivatives, stilbene derivatives, and arylamine derivatives can be used.
Binder resins include polymers and copolymers of vinyl compounds such as styrene, vinyl acetate, vinyl chloride, acrylic ester, methacrylic ester, vinyl alcohol, ethyl vinyl ether, polyvinyl acetal, polycarbonate, polyester, polyamide, polyurethane, cellulose Examples include ether, phenoxy resin, silicon resin, and epoxy resin.

As the binder resin, a transparent resin that does not absorb the light from the exposure light source of the image forming apparatus can be used among the resins having binding properties used in this field, and a resin similar to that contained in the charge generation layer can be used. One kind can be used alone or two or more kinds can be used in combination.
Among these, polystyrene, polycarbonate, polyarylate, and polyphenylene oxide are preferable because they have a volume resistance of 10 ¹³ Ω or more, excellent electrical insulation, and excellent film formability, potential characteristics, and the like, and polycarbonate is particularly preferable. .

The use ratio of the binder resin is not particularly limited, but is about 50 to 300 parts by weight with respect to 100 parts by weight of the charge transport material.
The charge transport layer is selected from a hole transport material, an electron transport material, an antioxidant, an ultraviolet absorber, a dispersion stabilizer, a sensitizer, a leveling agent, a plasticizer, an inorganic compound, or an organic compound as necessary. An appropriate amount of one or more of them may be included.

Similarly to the charge generation layer, the charge transport layer can be formed by preparing a coating solution for forming a charge transport layer and using a wet method, particularly a dip coating method.
As the solvent used for the preparation of the coating solution for forming the charge transport layer, it is possible to use one kind of the same solvents as those used for the preparation of the coating solution for forming the charge generation layer alone or in combination of two or more kinds. it can.

  Specifically, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene; dichloromethane, dichloroethane and carbon tetrachloride , Halogenated hydrocarbons such as chlorobenzene; ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, dioxane, dioxolane, propylene glycol monomethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether; ketones such as acetone, methyl ethyl ketone, cyclohexanone; ethyl acetate, acetic acid Esters such as methyl; dimethylformaldehyde, dimethylformamide, dimethylsulfoxide, etc. Among these, it is particularly preferable to use tetrahydrofuran and 1,3-dioxolane alone.

Other steps and conditions are in accordance with the formation of the intermediate layer and the charge generation layer.
Although the film thickness of a charge transport layer is not specifically limited, 5-40 micrometers is preferable and 10-30 micrometers is especially preferable.
When the thickness of the charge transport layer is less than 5 μm, the charge holding ability on the surface of the photoreceptor is lowered, and the contrast of the output image may be lowered. On the other hand, if the thickness of the charge transport layer exceeds 40 μm, the productivity of the photoreceptor may be lowered.

[Surface protective layer 15d]
As shown in FIG. 2, the photoreceptor of the present invention may have a surface protective layer on the photosensitive layer.
The protective layer has a function of improving the durability of the photoreceptor, is made of a binder resin, and may contain one or more of the same charge transport materials as those contained in the charge transport layer.
Examples of the binder resin include the same binders as those contained in the charge generation layer and the charge transport layer.

The surface protective layer can be formed by, for example, preparing a coating solution for forming a protective layer by dissolving a binder resin in an appropriate solvent, applying the coating solution to the surface of the photosensitive layer, and removing the organic solvent by drying. .
Other processes and conditions are in accordance with the formation of the intermediate layer, the charge generation layer, and the charge transport layer.
The thickness of the protective layer is not particularly limited, but is preferably 0.5 to 10 μm, and particularly preferably 1 to 5 μm.

If the thickness of the protective layer is less than 0.5 μm, the scratch resistance on the surface of the photoreceptor is inferior and the durability may be insufficient. If it exceeds 10 μm, the resolution of the photoreceptor may be lowered.
The image forming apparatus of the present invention includes a photosensitive member of the present invention, a charging unit that charges the electrophotographic photosensitive member, an exposure unit that exposes the charged electrophotographic photosensitive member to form an electrostatic latent image, The image forming apparatus includes a developing unit that develops and visualizes the electrostatic latent image formed by the exposure, and a transfer unit that transfers the image visualized by the development onto a recording medium.

The image forming apparatus of the present invention and the operation thereof will be described with reference to the drawings, but are not limited to the following description.
FIG. 3 is a schematic side view showing the configuration of the image forming apparatus of the present invention.
An image forming apparatus (laser printer) 100 in FIG. 3 includes a photoreceptor 1 of the present invention, an exposure unit (semiconductor laser) 31, a charging unit (charging unit) 32, a developing unit (developing unit) 33, and a transfer unit. The image forming apparatus includes a (transfer charger) 34, a conveyance belt (not shown), a fixing unit (fixing unit) 35, and a cleaning unit (cleaner) 36. Reference numeral 51 denotes a transfer sheet.

  The photosensitive member 1 is rotatably supported by the main body of the image forming apparatus 100 (not shown), and is driven to rotate in the direction of the arrow 41 around the rotation axis 44 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 1 to drive the photoconductor 1 to rotate at a predetermined peripheral speed. . The charger 32, the exposure unit 31, the developing unit (developing unit) 33, the transfer charging unit 34, and the cleaning unit (cleaner) 36 are arranged in this order along the outer peripheral surface of the photoconductor 1 and are indicated by arrows 41. The body 1 is provided from the upstream side to the downstream side in the rotation direction.

The charger 32 is a charging unit that uniformly charges the outer peripheral surface of the photoreceptor 1 to a predetermined potential.
The exposure unit 31 includes a blue semiconductor laser as a light source, and is charged by irradiating the surface of the multilayer photoreceptor 1 between the charger 32 and the developer 33 with the light of the laser beam output from the light source. The outer peripheral surface of the laminated photoreceptor 1 is exposed according to image information. The light is repeatedly scanned in the main scanning direction in the direction in which the rotation axis 44 of the multilayer photoconductor 1 extends, and these are imaged to sequentially form electrostatic latent images on the surface of the photoconductor 1. That is, the charge amount of the photoreceptor 1 uniformly charged by the charger 32 is different depending on whether the laser beam is irradiated or not, and an electrostatic latent image is formed.

  The developing unit 33 is a developing unit that develops an electrostatic latent image formed on the surface of the photoconductor 1 by exposure with a developer (toner), and is provided facing the photoconductor 1. A developing roller 33a for supplying toner to the toner, and a casing 33b for supporting the developing roller 33a so as to be rotatable about a rotation axis parallel to the rotation axis 44 of the photosensitive member 1 and containing a developer containing toner in the internal space thereof. Prepare.

  The transfer charger 34 transfers a toner image, which is a visible image formed on the outer peripheral surface of the photoreceptor 1 by development, between the stacked photoreceptor 1 and the transfer charger 34 from the direction of the arrow 42 by a conveying unit (not shown). Transfer means for transferring onto a transfer paper 51, which is a recording medium supplied to the printer. The transfer charger 34 is, for example, a contact-type transfer unit that includes a charging unit and transfers the toner image onto the transfer paper 51 by applying a charge having a polarity opposite to that of the toner to the transfer paper 51.

  The cleaner 36 is a cleaning unit that removes and collects toner remaining on the outer peripheral surface of the photoconductor 1 after the transfer operation by the transfer charger 34, and a cleaning blade 36 a that peels off toner remaining on the outer peripheral surface of the multilayer photoconductor 1. And a recovery casing 36b for storing the toner separated by the cleaning blade 36a. The cleaner 36 is provided together with a static elimination lamp (not shown).

  Further, the image forming apparatus 100 is provided with a fixing device 35 as fixing means for fixing the transferred image on the downstream side where the transfer paper 51 that has passed between the photoreceptor 1 and the transfer charger 34 is conveyed. It is done. The fixing device 35 includes a heating roller 35a having a heating unit (not shown), and a pressure roller 35b that is provided facing the heating roller 35a and is pressed by the heating roller 35a to form a contact portion.

Reference numeral 37 denotes a separating unit that separates the transfer paper and the photosensitive member, and 38 denotes a casing that houses each unit of the image forming apparatus.
The image forming operation by the electrophotographic apparatus 100 is performed as follows.
First, when the photosensitive member 1 is rotationally driven in the direction of the arrow 41 by the driving unit, the photosensitive member 1 is provided by the charger 32 provided on the upstream side in the rotational direction of the photosensitive member 1 with respect to the light imaging point by the exposure unit 31. Are uniformly charged to a predetermined positive potential.

Next, light corresponding to image information is irradiated from the exposure unit 32 to the surface of the photoreceptor 1. In this exposure, the surface charge of the portion irradiated with light is removed by this exposure, and a difference occurs between the surface potential of the portion irradiated with light and the surface potential of the portion not irradiated with light. A latent image is formed.
Toner is supplied to the surface of the photosensitive member 1 on which the electrostatic latent image is formed from a developing device 33 provided on the downstream side in the rotation direction of the photosensitive member 1 with respect to the light image formation point by the exposure means 33, and the electrostatic latent image. Is developed to form a toner image.

In synchronization with the exposure of the photoreceptor 1, the transfer paper 51 is supplied between the photoreceptor 1 and the transfer charger 34. The transfer charger 34 applies a charge having a polarity opposite to that of the toner to the supplied transfer paper 51, and the toner image formed on the surface of the photoreceptor 1 is transferred onto the transfer paper 51.
The transfer paper 51 onto which the toner image has been transferred is conveyed to the fixing device 35 by the conveying means, and is heated and pressurized when passing through the contact portion between the heating roller 35a and the pressure roller 35b of the fixing device 35, and the toner The image is fixed on the transfer paper 51 and becomes a robust image. The transfer paper 51 on which the image is formed in this manner is discharged to the outside of the electrophotographic apparatus 100 by the conveying means.

  On the other hand, the toner remaining on the surface of the photoreceptor 1 after the transfer of the toner image by the transfer charger 34 is separated from the surface of the multilayer photoreceptor 1 by the cleaner 36 and collected. The charge on the surface of the photoreceptor 1 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 photoreceptor 1 disappears. Thereafter, the photosensitive member 1 is further driven to rotate, and a series of operations starting from charging is repeated to form images continuously.

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

Production Example 1
The polyamide resin of the present invention was manufactured as described below.
First, a dimerization reaction is carried out at 230 ° C. for 5 hours using a higher unsaturated fatty acid methyl ester containing 72% methyl oleate, 18% methyl linoleate and 10% other higher saturated fatty acid methyl as a raw material. went. Next, unreacted fatty acid methyl ester fraction and isomerized fatty acid methyl ester fraction are removed from the obtained product by vacuum distillation (230 ° C./1 torr), and the residue is molecular distilled (230 ° C./0.1 torr). Thus, dicarboxylic acid dimethyl ester was obtained, and tricarboxylic acid trimethyl ester was obtained as a distillation residue.

Next, dicarboxylic acid dimethyl ester and tricarboxylic acid trimethyl ester are mixed at 7/3, 2% of Ni catalyst is added, and hydrogenation reaction is carried out at a reaction temperature of 200 ° C. for 15 hours at a hydrogen pressure of 30 kg / cm ² , thereby trimethyl tricarboxylate. Dicarboxylic acid dimethyl ester having a part of ester was obtained.

  To a flask having an internal volume of 4 liters, a stirrer, a thermometer, a nitrogen introduction tube having an introduction tube extending into the liquid, and a cooling condenser were attached. A solution (1 L) in which 1.0 carboxyl group equivalent of dimethyl ester of dicarboxylic acid was dissolved in methanol to a concentration of 50%, and 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane 1.0 The amino group equivalent was dissolved in methanol to a concentration of 50%, and the solution (1 L) was mixed with stirring at room temperature. The flask was cooled because the temperature of the solution increased by mixing. Next, the pressure was reduced (10 mmHg), nitrogen gas was introduced, the pressure was returned to normal pressure, the reaction system was maintained in a nitrogen atmosphere, and then the reaction temperature was gradually raised to distill off methanol. When the distillation of methanol stopped, dehydration or dealcoholization was performed by raising the reaction temperature to 150 ° C. over 1 hour. After the distillation of most of the water or alcohol was completed, the reaction temperature was raised to 200 ° C. over 30 minutes, and the reaction was carried out for 30 minutes under reduced pressure (10 mmHg). The reaction was removed from the flask, kept in a nitrogen atmosphere without cooling, and pelletized with an extruder.

Production Example 2
A polyamide resin was obtained in the same manner as in Production Example 1 except that in the above Production Example 1, instead of dicarboxylic acid dimethyl ester, a commercially available Halidimer 200 (Harima Kasei Co., Ltd.) was used after methyl esterification.

Production Example 3
A polyamide resin was obtained in the same manner as in Production Example 1 except that commercially available Empol 1018 (manufactured by Cognis) was used as a methyl ester instead of dicarboxylic acid dimethyl ester in Production Example 1.

Example 1
The photoreceptor shown in FIG. 1 was produced.
First, titanium oxide particles surface-treated with alumina and silica (trade name: MT-500SA, manufactured by Teika Co., Ltd., rutile crystal, average primary particle diameter 35 nm) 4 parts by weight and polyamide resin produced in Production Example 1 1 weight Part was added to a 1: 1 mixed solvent of n-propyl alcohol and tetrahydrofuran so as to have a solid content of 16% by weight, and dispersion treatment was carried out with a paint shaker for 8 hours to prepare 4 kg of an intermediate layer forming coating solution.

  The obtained coating solution for forming an intermediate layer is filled in a coating tank, the coating solution for forming an intermediate layer is filled in the coating tank, and an aluminum drum-shaped support (diameter (JISB-0601) in advance having a diameter of 30 mm and a length of 340 mm is used. Normal 10-point surface roughness Rz: processed to 0.80 μm) and then surface-washed) was dipped, pulled up and naturally dried to form an intermediate layer having a thickness of 1 μm.

  Next, 1 part by weight of titanyl phthalocyanine having an X-ray diffraction spectrum in which the Bragg angle (2θ ± 0.2 °) with respect to X-ray of CuKα1.541Å as a charge generation material has a main peak at 27.3 ° and a binder resin 1 part by weight of butyral resin (trade name: # 6000-C, manufactured by Denki Kagaku Kogyo Co., Ltd.) is mixed with 98 parts by weight of methyl ethyl ketone, and dispersed for 8 hours with a paint shaker to prepare 4 kg of a coating solution for forming a charge generation layer. did.

  The obtained coating solution for forming a charge generation layer was applied to the surface of the intermediate layer previously provided by the same method as that for forming the intermediate layer, and then naturally dried to form a charge generation layer having a thickness of 0.4 μm.

Next, 100 parts by weight of a triphenylamine compound having the following structure as a charge transport material, 150 parts by weight of a polycarbonate resin (trade name: PCZ-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a binder resin, and 0.02 part by weight of silicone oil were added. Then, 4 kg of a coating solution for forming a charge transport layer having a solid content of 25% by weight was prepared using tetrahydrofuran as a solvent.
The obtained charge transport layer forming coating solution was applied to the surface of the charge generation layer previously provided in the same manner as in the intermediate layer formation, and dried at 130 ° C. for 1 hour to form a charge transport layer having a thickness of 25 μm. Formed.
In this way, the photoreceptor shown in FIG. 1 was produced.

Example 2
The photoreceptor shown in FIG. 1 is produced in the same manner as in Example 1 except that the polyamide resin produced in Production Example 2 is used instead of the polyamide resin produced in Production Example 1 in the preparation of the intermediate layer forming coating solution. did.

Example 3
The photoreceptor shown in FIG. 1 is produced in the same manner as in Example 1 except that the polyamide resin produced in Production Example 3 is used instead of the polyamide resin produced in Production Example 1 in the preparation of the intermediate layer forming coating solution. did.

Example 4
The titanium oxide used in the preparation of the coating solution for forming the intermediate layer is replaced with 4 parts by weight of titanium oxide particles having a large particle size (trade name: CR-EL, manufactured by Ishihara Sangyo Co., Ltd., rutile crystal, average primary particle size 250 nm). A photoconductor shown in FIG. 1 was produced in the same manner as in Example 1 except that.

Example 5
First, the surface treatment agent methyl hydrogen polysiloxane (trade name: KF-99 (manufactured by Shin-Etsu Chemical Co., Ltd.)) with respect to 10 parts by weight of zinc oxide (trade name: ZS-032 (manufactured by Showa Denko KK) average primary particle size 25 nm). ) 0.5 parts by weight and 50 parts by weight of solvent toluene were mixed to form a suspension, and the mixture was further dispersed using a paint shaker and zirconia beads having a diameter of 1 mm as dispersion media. The suspension after the treatment was distilled under reduced pressure to remove the solvent, and the surface-treated zinc oxide particles were obtained. Furthermore, the zinc oxide was heat-treated at a temperature of 140 ° C. for 1 hour to produce zinc oxide particles surface-treated with methyl hydrogen polysiloxane.

Next, 4 parts by weight of the surface-treated zinc oxide particles and 1 part by weight of the polyamide resin produced in Production Example 1 are added to methyl alcohol so as to have a solid content concentration of 16% by weight, and dispersed for 8 hours using a paint shaker. Then, 4 kg of an intermediate layer forming coating solution was prepared.
A photoconductor shown in FIG. 1 was produced in the same manner as in Example 1 except that this intermediate layer forming coating solution was used.

Comparative Example 1
1 except that a commercially available polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.), which is a quaternary copolymer nylon, is used as a polyamide resin in the preparation of the intermediate layer forming coating solution. The photoreceptor shown in FIG.

Comparative Example 2
The photoreceptor shown in FIG. 1 is produced in the same manner as in Example 1 except that a commercially available polyamide resin (trade name: Vestamelt X1010, manufactured by Daicel Evonik) is used as the polyamide resin in the preparation of the intermediate layer forming coating solution. did.

Comparative Example 3
The photoreceptor shown in FIG. 1 is produced in the same manner as in Example 1 except that a commercially available polyamide resin (trade name: Macromelt 6239, manufactured by Henkel) is used as the polyamide resin in the preparation of the intermediate layer forming coating solution. did.
The electrical characteristics of the photoreceptors of Examples 1 to 5 and Comparative Examples 1 to 3 produced as described above were evaluated.
Further, the dispersibility of the coating solution for forming an intermediate layer used in the production of each photoconductor was evaluated.

<Electrical characteristics>
Each of the photoconductors of Examples 1 to 5 and Comparative Examples 1 to 3 manufactured as described above is a commercially available digital copying machine (trade name: AR-450S, Sharp) equipped with a corona discharge charger as a charging means for the photoconductor. A surface potential meter (trade name: model 344, Trek Co., Ltd.) is mounted on the digital copying machine, and the developer is removed from the digital copying machine. Instead, the surface potential of the photoconductor in the image forming process can be measured at the development site. The product was modified to an evaluation device for evaluating the initial electrical characteristics and electrical durability.

The digital copier before remodeling (trade name: AR-450S, manufactured by Sharp Corporation) is a negatively chargeable image forming apparatus that forms an image by a reversal development process by negatively charging the surface of the photoreceptor.
The surface potential of the photoconductor when not exposed to laser light using the above-described evaluation device in a normal temperature / normal humidity (N / N) environment at a temperature of 25 ° C. and a relative humidity of 50%. Measurement was made as a charging potential Vo (V), and the surface potential of the photoreceptor when exposed by laser light was measured as an exposure potential VL (V). The above measurement results were used as an evaluation index for initial electrical characteristics. As for the initial electrical characteristics, it was evaluated that the larger the absolute value of the charging potential Vo, the better the charging property, and the smaller the absolute value of the exposure potential VL, the better the responsiveness.

  Next, the surface potential meter was taken out from the above-described evaluation apparatus, and the developer was mounted again and returned to the copying machine. Using this copying machine, test images of a predetermined pattern were formed on 100,000 sheets of recording paper. After completing the image formation of 100,000 sheets by the copying machine, the developing device is taken out again, the above-mentioned surface potential meter is attached to the developing portion and returned to the evaluation apparatus, and the charging potential Vo (V) and the exposure potential VL are the same as in the initial stage. (V) was measured respectively.

Similar evaluations were performed in a low temperature / low humidity (L / L) environment at a temperature of 5 ° C and a relative humidity of 20%, and a high temperature / high humidity (H / H: High) at a temperature of 35 ° C and a relative humidity of 80%. It was carried out in a Temperature / High Humidity environment.
It was evaluated that the smaller the potential fluctuation ΔVL, the better the stability of the electrical characteristics.

The electrical characteristics were evaluated according to the following criteria.
○: Good in all environments ΔVL Less than 60V in all environments and use.
Δ: Slightly poor ΔVL 60 V or more and less than 80 V in any environment.
X: Defect ΔVL 80 V or higher in any environment.

<Applicability>
The intermediate layer coating solution was applied to an aluminum-deposited PET sheet with an applicator and naturally dried to prepare a coating film having only a 1 μm intermediate layer, and the presence or absence of cloudiness was visually observed.
○: Good ×: Cloudy <Image evaluation>
：: Good ○: No problem in actual use, but there are minute black spots ×: Fogging generated The results obtained are shown in Table 1.

From the evaluation results in Table 1, the following can be understood.
Photoreceptors using the polyamide resin of the present invention (Examples 1 to 5) have potential changes during repeated use in any environment compared to conventional photoreceptors using a polyamide resin (Comparative Examples 1 to 3). It can be seen that a good image density can be realized at all times.

In Example 4, although there was no problem in practical use, there was a slight black spot.
In Example 5, the charging potential tended to decrease with repeated use.
On the other hand, when neither the higher aliphatic carboxylic acid structure nor the alicyclic diamine structure was present (Comparative Example 1), the polyamide resin had high hygroscopicity, and therefore, the residual potential was high particularly under low temperature and low humidity, affecting VL.

In the case where it does not have a higher aliphatic carboxylic acid structure but has an alicyclic diamine structure (Comparative Example 2), since the electrical resistance of the resin itself is high, the sensitivity is generally poor.
In the case of having a higher aliphatic carboxylic acid structure but not having an alicyclic diamine structure (Comparative Example 3), the coating film was easily agglomerated when the solvent was evaporated, and the coating film became cloudy.
From the above, it can be seen that the photoreceptor of the present invention can realize good image characteristics with little sensitivity change even from low temperature / low humidity to high temperature / high humidity.

According to the present invention, it is possible to provide a photoconductor capable of realizing good image characteristics with little change in sensitivity even at low temperature / low humidity, and an image forming apparatus including the photoconductor.
In addition, the coating liquid for coating and forming the intermediate layer of the photoreceptor of the present invention can maintain a desired dispersion state for a long period of time, and can form a coating film without coating unevenness even after long-term storage. it can.

1, 20b, 20d Electrophotographic photoreceptor 11 Conductive support 11b, 11d Charge generation layer 12b, 12d Charge transport layer 13b, 13d Conductive support 14b, 14d Intermediate layer 15d Surface protective layer

31 Exposure means (semiconductor laser)
32 Charging means (charger)
33 Developing means (developer)
33a Developing roller 33b Casing 34 Transfer means (transfer charger)
35 Fixing means (fixing device)
35a Heating roller 35b Pressure roller

36 Cleaning means (cleaner)
36a Cleaning blade 36b Recovery casing 37 Separating means 38 Housing 41, 42 Arrow 44 Rotating axis 51 Transfer paper 100 Electrophotographic apparatus (laser printer)

Claims (10)

Comprising an intermediate layer between the conductive support and the photosensitive layer;
The intermediate layer contains at least metal oxide fine particles and a binder resin,
An electrophotographic photoreceptor, wherein the binder resin is a polyamide resin which is a condensate of an alicyclic diamine and a higher aliphatic di- or tricarboxylic acid or an alkyl ester thereof or a mixture thereof.   The electrophotographic photosensitive member according to claim 1, wherein the alicyclic diamine is a cyclohexylene-based diamine.   The alicyclic diamine is 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, 1-amino-3-aminomethyl-2,5,6-trimethylcyclohexane or 1-amino-4- ( The electrophotographic photosensitive member according to claim 1, which is a cyclohexylene-based diamine selected from 4′-aminocyclohexylmethyl) cyclohexane.   The electrophotography according to any one of claims 1 to 3, wherein the higher aliphatic di- or tricarboxylic acid is a two- or three-molecule addition reaction product of oleic acid, linoleic acid or an alkyl ester thereof or a mixture thereof. Photoconductor.   The electrophotographic photosensitive member according to claim 1, wherein the metal oxide fine particles are titanium oxide.   The electrophotographic photosensitive member according to claim 1, wherein the metal oxide fine particles are titanium oxide particles having a number average primary particle diameter of 30 to 50 nm.   The electrophotographic photosensitive member according to claim 1, wherein the polyamide resin has a number average molecular weight of 5,000 to 80,000.   The electrophotographic photoreceptor according to claim 1, wherein the metal oxide fine particles are contained in a proportion of 50 to 1000 parts by weight with respect to 100 parts by weight of the polyamide resin.   9. The laminated photosensitive layer according to claim 1, wherein the photosensitive layer is a laminated photosensitive layer in which a charge generation layer containing at least a charge generation material and a charge transport layer containing a charge transport material are laminated in this order. The electrophotographic photoreceptor described in 1.   The electrophotographic photosensitive member according to claim 1, a charging unit for charging the electrophotographic photosensitive member, and exposing the charged electrophotographic photosensitive member to form an electrostatic latent image. An exposure unit, a development unit that develops and visualizes the electrostatic latent image formed by the exposure, and a transfer unit that transfers the image visualized by the development onto a recording medium. An image forming apparatus.

Images