JP2013225162A - Electrophotographic photoreceptor, process cartridge using the photoreceptor, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrophotographic photoreceptor that has proper electrical characteristics, can form good images even after repeated use for a long period, and has strong resistance against optical fatigue; and an electrophotographic device using the electrophotographic photoreceptor.SOLUTION: Provided are an electrophotographic photoreceptor that has a photosensitive layer on a conductive support, the photosensitive layer containing a compound represented by the following formula (2); and an image forming apparatus that has the electrophotographic photoreceptor mounted thereon. In the formula (2), X represents an n-valent organic group having carbon atoms of 30 or less; Y represents monovalent organic group having carbon atoms of 15 or less; Z represents an n+1-valent organic group having carbon atoms of 15 or less; nrepresents an integer of 1 or more and 10 or less; and nrepresents an integer of 1 or more and 10 or less.

Description

  The present invention relates to an electrophotographic photosensitive member having a photosensitive layer, a process cartridge using the photosensitive member, and an image forming apparatus. The electrophotographic photosensitive member according to the present invention can be suitably used for electrophotographic printers, facsimiles, copying machines and the like.

C. F. The electrophotographic technology invented by Carlson is not limited to the field of copiers, because it can provide images with immediacy, high quality, and high storage stability. Has also become widespread and shows a huge spread.
For photoconductors that are the core of electrophotographic technology, photoconductors that use organic photoconductive materials, which have the advantages of being non-polluting, easy to form and easy to manufacture, are mainly used. Is used.

In particular, a so-called multilayer photoreceptor in which a charge generation layer and a charge transport layer are laminated can provide a more sensitive photoreceptor, a wide range of material selection, and a highly safe photoreceptor. Since it is highly productive and relatively advantageous in terms of cost, it is now the mainstream of photoconductors and is produced in large quantities.
On the other hand, digitization for image formation is rapidly progressing in order to obtain higher quality images and to store and edit input images freely. In the past, digital image formation was limited to laser printers, LED printers, and some color laser copiers, which are output devices of word processors and personal computers. Digitization was almost completely achieved even in the field of ordinary copying machines where mainstream image formation was the mainstream.

  When such digital image formation is performed, laser light or LED light is mainly used as a light input light source for digital signals to the photosensitive member. As a transmission wavelength of a light input light source that is widely used at present, near-infrared light of 780 nm or 660 nm and long-wavelength light close thereto are widely used. In recent years, blue lasers have been put into practical use, and it has become possible to use light having a short wavelength of 400 to 500 nm as a light source for light input. As a photoconductor used for digital image formation, it is necessary to have an effective sensitivity to these various light input light sources, and various materials have been studied so far. In addition to high sensitivity, it has sufficient chargeability, low dark decay after charging, low residual potential, and good stability during repeated use of these characteristics. Basic characteristics are required.

  However, in reality, in repeated use in a copying machine or printer, there is a problem that the electrical characteristics deteriorate due to the gradual deterioration of the photosensitive layer. There is also a known problem that even when the photoconductor is subjected to light fatigue due to light from a fluorescent lamp or the like, a change in residual potential, charging, etc. occurs greatly. There is a demand for a photoreceptor that is less damaged by repeated use, has excellent light fatigue characteristics, and has stable electrical characteristics.

As a technical measure against such photoconductor electric characteristic fluctuation, a method for adding various deterioration preventing / stabilizing agents to the photoconductor has been studied. For example, Patent Document 1 proposes a method of adding an electron-withdrawing compound, a cyanovinyl compound, or the like.
As described in the above specification, these electron-withdrawing compounds and cyanovinyl compounds are mainly added to the charge transport layer, which is the outermost surface layer of the photoreceptor, in combination with a charge transport material and a binder resin. However, in this case, the increase in residual potential is suppressed by the addition of the compound, but the electrical characteristics are deteriorated immediately after being exposed to external light such as a fluorescent lamp, in particular, the charging property is extremely deteriorated. It is known that this problem will occur, and immediate improvement is desired.

JP-A-3-48852

Up to now, in the development and production of electrophotographic photoreceptors, it has been necessary to prepare a photoreceptor that meets various apparatus conditions such as a charging device, a light input light source, and a developing device. Even if a photoconductor is prepared and a good image can be formed in the initial stage, the image may deteriorate significantly immediately after light fatigue exposed to external light. Verification was necessary.
The present invention has been made in view of the above-described problems. That is, an object of the present invention is to provide an electrophotographic photosensitive member that has favorable electrical characteristics and is resistant to light fatigue that can be exposed to external light and can form a good image immediately after light fatigue. Another object is to provide a process cartridge and an electrophotographic apparatus using the electrophotographic photosensitive member.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have included a compound having a specific structure in the photosensitive layer, so that it has suitable electrical characteristics, and at the same time, it is exposed to external light and is subjected to light fatigue. It has been found that an electrophotographic photosensitive member that is capable of forming a good image immediately and that is resistant to light fatigue can be obtained. Further, the present inventors have found that a process cartridge and an electrophotographic apparatus using the photoreceptor can form a good image, and have completed the present invention.

That is, the gist of the present invention is an electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a compound having a structure of the following formula (2). Exist.

(In the formula (2), X is an organic group having 30 or less of _{n 3} valent carbon, Y represents a monovalent organic group, Z is an organic group having 15 or less of _n 2 +1 divalent carbon below 15 carbon atoms N ₂ represents an integer of 1 to 10, and n ₃ represents an integer of 1 to 10.
Further, the second aspect of the present invention resides in a process cartridge using the electrophotographic photosensitive member, and the third aspect of the present invention resides in an image forming apparatus using the electrophotographic photosensitive member.

According to the present invention, when a specific compound is used, it is possible to provide an electrophotographic photosensitive member with high sensitivity and low residual potential, which suppresses deterioration of electrical characteristics immediately after exposure to external light and light fatigue.
In addition, an electrophotographic photosensitive member having excellent electrical property stability, in particular, excellent image quality stability can be obtained conventionally, and a high-performance image forming apparatus using the same can be provided.
Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of the embodiments of the present invention, and is appropriately modified and implemented without departing from the spirit of the present invention. can do.

1 is a schematic diagram illustrating a main configuration of an embodiment of an image forming apparatus of the present invention. It is a powder X-ray-diffraction spectrum of the oxytitanium phthalocyanine used in Examples 1-14 and Comparative Examples 1-5 of this invention.

Hereinafter, the embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is a representative example of the embodiments of the present invention, and may be appropriately modified without departing from the spirit of the present invention. Can be implemented.
<Compound represented by Formula (1)>
The electrophotographic photoreceptor of the present invention is an electrophotographic photoreceptor having a photosensitive layer on a conductive support, and the photosensitive layer contains a compound having a structure represented by the following formula (1).

In the formula (1), X represents an organic group of _{monovalent n} having 30 or less carbon atoms, Y represents a monovalent organic group having up to 15 carbon atoms, _{n 1} represents an integer of 2 to 10.
X is a n ₁ monovalent organic group having 30 or less carbon atoms, preferably an organic group having 20 or less carbon atoms, more preferably an organic group having not more than 15 carbon atoms.
X is preferably an organic group having at least one group selected from an aromatic group which may have a substituent and a condensed polycyclic group which may have a substituent. It is particularly preferable that the number of rings constituting the organic group is 4 or less.

  Examples of the aromatic group in X include a benzenoid aromatic group, a non-benzenoid aromatic group, a heteroaromatic ring group, and the like, among which a benzenoid aromatic group or a heteroaromatic ring group is preferable. The number of rings of the aromatic group in X is preferably 5 or less, more preferably 3 or less, and particularly preferably 2 or less. Examples of the benzenoid aromatic group include polyvalent groups such as benzene, naphthalene, anthracene, pyrene, and perylene, and a polyvalent group of benzene or naphthalene is preferable. In addition, examples of the non-benzenoid aromatic group include polyvalent groups such as azulene and ferrocene. In addition, examples of the heteroaromatic ring group include polyvalent groups such as pyridine, thiophene, pyrrole, quinoline, and indole, and a polyvalent group of pyridine or quinoline is preferable.

As the condensed polycyclic group in X, those having 5 or less condensed rings are preferable, and those having 3 or less are particularly preferable. Specifically, for example, polyvalent groups such as naphthalene, anthracene, pyrene, perylene, tetralin, carbazole, anthraquinone, and the like are exemplified, and a polyvalent group of naphthalene or anthraquinone is preferable.
X is a group having at least one group selected from an aromatic group which may have a substituent and a condensed polycyclic group which may have a substituent. It may have a collective structure. In this case, the connection means a state in which the rings are directly bonded by a single bond or a state in which the rings are bonded through a linking group. The ring structure to be connected is preferably an aromatic group, particularly a divalent group of benzene or naphthalene. Examples of the linking group used in the ring assembly group include an alkylene group, an ether group, a thioether group, a ketone group, a thioketone group, a sulfide group, a sulfoxide group, a sulfone group, a selenide group, and a selenoxide group. A sulfone group is preferred.

In consideration of the solubility of the compound represented by the formula (1) in the photosensitive layer, X is preferably 4 or less, more preferably 3 or less, and more preferably 2 It is particularly preferred that
Y is an organic group having 15 or less carbon atoms, preferably an organic group having 12 or less carbon atoms, and more preferably an organic group having 10 or less carbon atoms. Among them, Y is preferably an alkyl group which may have a substituent, an aromatic group which may have a substituent, or a condensed polycyclic group which may have a substituent.

The alkyl group for Y may be linear, branched or cyclic, but is preferably an alkyl group having 10 or less carbon atoms, more preferably 8 carbon atoms. The following alkyl groups.
Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a hexyl group, an ethylhexyl group, a cyclohexyl group, and a stearyl group.

  Examples of the aromatic group in Y include a benzenoid aromatic group, a non-benzenoid aromatic group, a heteroaromatic ring group, and the like, and among them, a benzenoid aromatic group or a heteroaromatic ring group is preferable. Further, the number of rings of the aromatic group in Y is preferably 5 or less, more preferably 3 or less, and still more preferably 2 or less. Examples of the benzenoid aromatic group in Y include monovalent groups such as benzene, naphthalene, anthracene, pyrene, and perylene, and a monovalent group of benzene or naphthalene is preferable. Examples of non-benzenoid aromatic groups include monovalent groups such as azulene and ferrocene. Examples of the heteroaromatic ring group include monovalent groups such as pyridine, thiophene, pyrrole, quinoline, and indole. Among these monovalent groups, a monovalent group of pyridine or quinoline is preferable.

As the condensed polycyclic group in Y, those having 5 or less condensed rings are preferable, and those having 3 or less are particularly preferable. Specific examples include monovalent groups such as naphthalene, anthracene, pyrene, perylene, tetralin, carbazole, anthraquinone, and the like, and monovalent groups of naphthalene or anthraquinone are preferable.
The alkyl group, aromatic group, and condensed polycyclic group of X and Y may each independently have a substituent. As the substituent, a substituent having 20 or less atoms is preferable, and a substituent having 15 or less atoms is more preferable. Specific examples of the substituent include alkyl groups such as alkyl groups, ethyl groups and propyl groups; alkoxy groups such as methoxy groups, ethoxy groups and propoxy groups; aryloxy groups such as phenoxy groups; phenyl groups and naphthyl groups. Aryl groups such as groups; formyl groups; acyloxy groups such as acetoxy groups; alkoxysulfonyl groups such as methoxysulfonyl and ethoxysulfonyl; acetyl groups, propionyl groups, butyryl groups, benzoyl groups, toluoyl groups, naphthoyl groups, benzenesulfonyl groups, mesyl groups Acyl groups such as groups; halogen groups such as fluorine, chlorine, bromine; nitro groups; cyano groups; azo groups.

  Furthermore, these substituents may further have a substituent having 10 or less atoms. Specific examples of the substituent that may be present in this case include, for example, an alkyl group such as a methyl group, an ethyl group, and a propyl group; an alkoxy group such as a methoxy group, an ethoxy group, and a propoxy group; and a phenoxy group. Aryloxy group; aryl group such as phenyl group and naphthyl group; formyl group; acyloxy group such as acetoxy group; alkoxysulfonyl group such as methoxysulfonyl and ethoxysulfonyl; acetyl group, propionyl group, butyryl group, benzoyl group, toluoyl group, And acyl groups such as naphthoyl group, benzenesulfonyl group and mesyl group; halogen groups such as fluorine, chlorine and bromine; nitro group; cyano group;

These substituents may be bonded directly or using a known linking group to form a ring structure.
Further, as these substituents, those having a substituent constant σ _p in Hammett's rule of 0 or more are preferable, groups having a value of σ _p of 0.3 or more are more preferable, and values of σ _p are 0.4 or more. Is particularly preferred. On the other hand, if the value of σ _p is too large, the light fatigue characteristics may be deteriorated. Therefore, a group of 0.7 or less is preferable, and a group of 0.6 or less is particularly preferable. The substituent may have a hetero atom.

Here, Hammett's rule is an empirical rule used to explain the effect of a substituent in an aromatic compound on the electronic state of an aromatic ring, and quantifies the degree of electron donation / suction of the substituent. Value. Specific theory and specific numerical values are described in Chemical Society of Japan, “Basic Guide for Chemicals II, 4th revised edition”, Maruzen Co., Ltd., published on September 30, 1993, p. 364 to 365, etc., and are shown below.

Further, n ₁ in the above formula (1) represents an integer of 2 or more and 10 or less, and preferably 3 or more, more preferably 4 or more when considering combination compatibility with the charge transport material used in the photosensitive layer. Thus, it is preferably 8 or less, more preferably 6 or less.
In addition, the introduction of a substituent such as a nitro group or a cyano group into the compound according to the present invention may cause a decrease in electrical properties due to light fatigue, and further a compound having acute toxicity and toxicity such as mutagenesis. Since it may become, it is not preferable.

Further, the compound according to the present invention preferably has no substantial light absorption in the wavelength region of the exposure light for exposing the electrophotographic photosensitive member of the present invention in order to improve the sensitivity of the photosensitive member. Here, “not having substantial light absorption” means that the layer containing the compound according to the present invention has a light transmittance of 90% or more with respect to the exposure light for exposing the electrophotographic photosensitive member of the present invention. Say.
Specific examples of the compound represented by the formula (1) according to the present invention are given below, but the compound according to the present invention is not limited to the compounds exemplified below. Hereinafter, these compounds are referred to as “Exemplary Compound 1 to Exemplary Compound 90” as appropriate.

<Compound represented by Formula (2)>
The electrophotographic photosensitive member of the present invention is an electrophotographic photosensitive member having a photosensitive layer on a conductive support, and the photosensitive layer contains a compound having a structure represented by the following formula (2).

In the formula (2), X is an organic group having 30 or less of _{n 3} valent carbon, Y is a monovalent organic group having up to 15 carbon atoms, Z is represents a _n 2 +1 monovalent organic group 15 or less carbon atoms, n ₂ is 1 to 10 integer, _{n 3} represents an integer of 1 to 10.
X in the formula (2) differs depending on whether the valence is n ₁ or n _3, but is an organic group derived from the same organic group as X in the formula (1). It is the same organic group as Y in 1).

Z is an n ₂ +1 valent organic group having 15 or less carbon atoms, preferably an organic group having 12 or less carbon atoms, and more preferably an organic group having 10 or less carbon atoms. Among these, Z is preferably a hydrocarbon group that may have a substituent, an aromatic group that may have a substituent, or a condensed polycyclic group that may have a substituent.
The hydrocarbon group for Z may be linear, branched or cyclic, but is preferably a hydrocarbon group having 10 or less carbon atoms, more preferably carbon. It is a hydrocarbon group having a number of 8 or less. Although the valence of Z varies depending on the value of n ₂ , specifically, for example, a polyvalent group derived from a hydrocarbon such as methane, ethane, propane, methylpropane, butane, 2-methylbutane, hexane, and cyclohexane Can be mentioned.

  Examples of the aromatic group in Z include a benzenoid aromatic group, a non-benzenoid aromatic group, a heteroaromatic ring group, and the like, among which a benzenoid aromatic group or a heteroaromatic ring group is preferable. The number of rings of the aromatic group in Z is preferably 5 or less, more preferably 3 or less, and particularly preferably 2 or less. Examples of the benzenoid aromatic group include polyvalent groups such as benzene, naphthalene, anthracene, pyrene, and perylene, and a polyvalent group of benzene or naphthalene is preferable. In addition, examples of the non-benzenoid aromatic group include polyvalent groups such as azulene and ferrocene. In addition, examples of the heteroaromatic ring group include polyvalent groups such as pyridine, thiophene, pyrrole, quinoline, and indole, and a polyvalent group of pyridine or quinoline is preferable.

As the condensed polycyclic group in Z, those having 5 or less condensed rings are preferable, and those having 3 or less are particularly preferable. Specifically, for example, polyvalent groups such as naphthalene, anthracene, pyrene, perylene, tetralin, carbazole, anthraquinone, and the like are exemplified, and a polyvalent group of naphthalene or anthraquinone is preferable.
The hydrocarbon group, aromatic group and condensed polycyclic group of X, Y and Z in formula (2) may each independently have a substituent. In this case, examples of the substituent that may be included in the formula (1) include substituents that the alkyl group, aromatic group, and condensed polycyclic group of X and Y may have, The same applies to preferable substituents.

N ₂ in the formula (2) represents an integer of 1 or more and 10 or less, and preferably 6 or less, more preferably 4 or less, and still more preferably when considering combination compatibility with the charge transport material used in the photosensitive layer. 3 or less, particularly preferably 2 or less.
Further, n ₃ in the above formula (2) represents an integer of 1 or more and 10 or less, and preferably 6 or less, more preferably 4 or less, considering combination compatibility with the charge transport material used in the photosensitive layer. More preferably, it is 3 or less, and particularly preferably 2 or less.

In addition, the introduction of a substituent such as a nitro group or a cyano group into the compound according to the present invention may cause a decrease in electrical properties due to light fatigue, and further a compound having acute toxicity and toxicity such as mutagenesis. Since it may become, it is not preferable.
Further, the compound according to the present invention preferably has no substantial light absorption in the wavelength region of the exposure light for exposing the electrophotographic photosensitive member of the present invention in order to improve the sensitivity of the photosensitive member. Here, “not having substantial light absorption” means that the layer containing the compound according to the present invention has a light transmittance of 90% or more with respect to the exposure light for exposing the electrophotographic photosensitive member of the present invention. Say.

  Specific examples of the compound represented by the formula (2) according to the present invention are given below, but the compound according to the present invention is not limited to the compounds exemplified below. Hereinafter, these compounds are referred to as Exemplified Compound 91 to Exemplified Compound 155 as appropriate.

The configuration of the electrophotographic photoreceptor of the present invention will be described below.
<Conductive support>
As the conductive support used in the electrophotographic photosensitive member of the present invention, for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper and nickel, and conductive powders such as metal, carbon and tin oxide are added. Mainly used are resin materials provided with conductivity and resins, glass, paper, and the like obtained by depositing or coating a conductive material such as aluminum, nickel, ITO (indium tin oxide) on the surface. As a form, a drum shape, a sheet shape, a belt shape or the like is used. A conductive material having an appropriate resistance value may be applied to a conductive support made of a metal material in order to control conductivity, surface properties, etc. or to cover defects.

When a metal material such as an aluminum alloy is used as the conductive support, it may be used after an anodized film is applied. When an anodized film is applied, it is desirable to perform a sealing treatment by a known method. For example, an anodic oxidation film is formed by anodizing in an acidic bath such as chromic acid, sulfuric acid, oxalic acid, boric acid, sulfamic acid, etc. give. In the case of anodic oxidation in sulfuric acid, the sulfuric acid concentration is 100 to 300 g / L, the dissolved aluminum concentration is 2 to 15 g / L, the liquid temperature is 15 to 30 ° C., the electrolysis voltage is 10 to 20 V, and the current density is 0.5 to Although it is preferable to set within the range of ² A / dm ² , it is not limited to the above conditions.

It is preferable to perform a sealing treatment on the anodic oxide film thus formed. The sealing treatment may be performed by a known method. For example, it is immersed in an aqueous solution containing nickel fluoride as a main component, or immersed in an aqueous solution containing nickel acetate as a main component. A high temperature sealing treatment is preferably performed.
The concentration of the nickel fluoride aqueous solution used in the case of the low-temperature sealing treatment can be appropriately selected, but more preferable results are obtained when it is used in the range of 3 to 6 g / L. Moreover, in order to advance a sealing process smoothly, as processing temperature, it is 25-40 degreeC, Preferably it is 30-35 degreeC, Moreover, nickel fluoride aqueous solution pH is 4.5-6.5, Preferably it is 5 It is better to process in the range of .5 to 6.0. As the pH adjuster, oxalic acid, boric acid, formic acid, acetic acid, sodium hydroxide, sodium acetate, aqueous ammonia and the like can be used. The treatment time is preferably in the range of 1 to 3 minutes per 1 μm of film thickness. In order to further improve the physical properties of the film, cobalt fluoride, cobalt acetate, nickel sulfate, a surfactant or the like may be added to the nickel fluoride aqueous solution. Subsequently, it is washed with water and dried to finish the low temperature sealing treatment.

  As the sealing agent in the case of the high-temperature sealing treatment, an aqueous solution of a metal salt such as nickel acetate, cobalt acetate, lead acetate, nickel acetate-cobalt, and barium nitrate can be used, and it is particularly preferable to use nickel acetate. . The concentration in the case of using an aqueous nickel acetate solution is preferably 5 to 20 g / L. The treatment temperature is 80 to 100 ° C., preferably 90 to 98 ° C., and the pH of the nickel acetate aqueous solution is preferably 5.0 to 6.0.

  Here, aqueous ammonia, sodium acetate, or the like can be used as the pH adjuster. The treatment time is 10 minutes or longer, preferably 20 minutes or longer. In this case as well, sodium acetate, organic carboxylic acid, anionic and nonionic surfactants may be added to the nickel acetate aqueous solution in order to improve the film properties. Subsequently, it is washed with water and dried to finish the high temperature sealing treatment. When the average film thickness is thick, stronger sealing conditions are required due to the higher concentration of the sealing liquid and high temperature / long-time treatment. Accordingly, productivity is deteriorated and surface defects such as spots, dirt, and dusting are likely to occur on the coating surface. From such a point, it is preferable that the average film thickness of the anodic oxide coating is usually 20 μm or less, particularly 7 μm or less.

  The support surface may be smooth, or may be roughened by using a special cutting method or polishing. Further, it may be roughened by mixing particles having an appropriate particle diameter with the material constituting the support. In order to reduce the cost, it is possible to use the drawing tube as it is without cutting. Especially when using non-cutting aluminum supports such as drawing, impact processing, ironing, etc., the process eliminates dirt, foreign matter, etc. on the surface, small scratches, etc., and a uniform and clean support can be obtained. Therefore, it is preferable.

<Coating liquid for undercoat layer formation>
An undercoat layer may be provided between the conductive support and the photosensitive layer described later for improving adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used. The undercoat layer may be a single layer or a plurality of layers.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide, calcium titanate, titanium Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium acid and barium titanate. One kind of these particles may be used alone, or a plurality of kinds of particles may be mixed and used in an arbitrary combination and ratio.

Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable.
The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. Any one of these treatments may be used, or two or more thereof may be applied.

As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. In addition, the titanium oxide particles may have only one crystal type, or two or more crystal types may be included in any combination and ratio.
Various particle diameters can be used as the particle diameter of the metal oxide particles. Among them, the average primary particle diameter is usually 10 nm or more from the viewpoint of the characteristics of the binder resin as a raw material for the undercoat layer and the stability of the liquid. Usually, it is 100 nm or less, preferably 50 nm or less. This average primary particle size is defined by a value obtained by measurement from a TEM photograph.

  The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. The binder resin used for the undercoat layer is epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, polyurethane resin, polyimide resin, chloride resin. Vinylidene resin, polyvinyl acetal resin, vinyl chloride-vinyl acetate copolymer, polyvinyl alcohol resin, polyurethane resin, polyacrylic acid resin, polyacrylamide resin, polyvinyl pyrrolidone resin, polyvinyl pyridine resin, water-soluble polyester resin, cellulose such as nitrocellulose Ester resin, cellulose ether resin, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium chelate compound, zirconi Organic zirconium compounds of the arm alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanyl alkoxide compound, silane coupling agent, and the like. In addition, these may be used independently or may use 2 or more types together by arbitrary combinations and ratios. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamide, modified polyamide, and the like are preferable because they exhibit good dispersibility and coating properties.

The mixing ratio of the metal oxide particles to the binder resin used for the undercoat layer can be arbitrarily selected, but it is usually applied in the range of 10 to 500 parts by weight with respect to 100 parts by weight of the binder resin. It is preferable in terms of liquid stability and coatability.
The thickness of the undercoat layer can be arbitrarily selected, but is usually 0 from the viewpoint of improving the electrical characteristics, strong exposure characteristics, image characteristics, repeat characteristics, and applicability at the time of manufacture of the electrophotographic photosensitive member. 0.01 μm or more, preferably 0.1 μm or more, and usually 30 μm or less, preferably 20 μm or less.

<Charge generating material>
The photosensitive layer formed on the conductive support may have a single layer structure in which the charge generation material and the charge transport material are present in the same layer and dispersed in the binder resin, or the charge generation material may be Any of a layered structure in which a charge generation layer dispersed in a binder and a charge transport material are functionally separated into a charge transport layer dispersed in a binder resin may be used. In the present invention, it is preferable to use a charge generating material and a dye / pigment as necessary. Specific examples thereof include, for example, selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene pigments, quinacridone pigments, indigo pigments, perylene pigments, Various photoconductive materials such as an organic pigment such as a polycyclic quinone pigment, an anthrone pigment, and a benzimidazole pigment can be used, and an organic pigment, a phthalocyanine pigment, and an azo pigment are particularly preferable.

Specific examples of the phthalocyanine used include metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, and other metals, or oxides, halides, hydroxides, and alkoxides thereof. Various crystal forms of such coordinated phthalocyanines are used. In particular, titanyl phthalocyanines (also known as oxytitanium) such as X-type, τ-type metal-free phthalocyanine, A-type (also known as β-type), B-type (also known as α-type), and D-type (also known as Y-type), which are highly sensitive crystal types Phthalocyanine), vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and I, IIS
A μ-oxo-aluminum phthalocyanine dimer such as a mold is preferred. Among these phthalocyanines, A type (β type), B type (α type), D type (Y type) oxytitanium phthalocyanine, II type chlorogallium phthalocyanine, V type hydroxygallium phthalocyanine, G type μ-oxo- Gallium phthalocyanine dimer and the like are particularly preferable. In particular, oxytitanium phthalocyanine preferably has a clear diffraction peak mainly at a Bragg angle (2θ ± 0.2 °) of 27.3 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray.

In addition, the oxytitanium dirocyanine has a clear diffraction peak at a Bragg angle (2θ ± 0.2 °) of 9.0 ° to 9.7 ° in a powder X-ray diffraction spectrum by CuKα characteristic X-ray. preferable.
In the oxytitanium phthalocyanine, the chlorine content in the crystal is preferably 1.5% by mass or less. The chlorine content is determined from elemental analysis.

  In the oxytitanium phthalocyanine crystal, the ratio of the chlorinated oxytitanium phthalocyanine represented by the following formula (3) is higher than the unsubstituted oxytitanium phthalocyanine represented by the following formula (4). The ratio is 0.070 or less. The mass spectral intensity ratio is preferably 0.060 or less, more preferably 0.055 or less. In the production, when the dry grinding method is used for amorphization, 0.02 or more is preferable, and when the acid paste method is used for amorphization, 0.03 or less is preferable. The amount of chlorine substitution is measured based on the technique disclosed in Japanese Patent Application Laid-Open No. 2001-115054.

The particle size of these oxytitanyl phthalocyanines varies greatly depending on the production method and the crystal conversion method, but considering the dispersibility, the primary particle size is preferably 500 nm or less, and from the viewpoint of coating film formability, it is preferably 300 nm or less. .
In addition to the chlorinated oxytitanium phthalocyanine, the oxytitanium phthalocyanine may contain, for example, a fluorine atom, a nitro group, or a cyano group. Alternatively, various oxytitanium phthalocyanine derivatives substituted with a substituent such as a sulfone group may be contained.

When using an azo pigment, various known bisazo pigments and trisazo pigments are preferably used. An example of a preferable azo pigment is shown in the following formula (5). In the following formula (5), Cp ¹ to Cp ³ represent couplers.

In the above formula (5), the following structures are preferable as the couplers Cp ^{1 to} Cp ³ .

  Examples of the binder resin used for the charge generation layer in the function-separated photoreceptor include polyvinyl butyral resin, polyvinyl formal resin, partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal, acetal, etc. Polyvinyl acetal resin, polyarylate resin, polycarbonate resin, polyester resin, modified ether polyester resin, phenoxy resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polystyrene resin, acrylic resin, methacrylic resin, polyacrylamide Resin, polyamide resin, polyvinyl pyridine resin, cellulose resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, chloride Vinyl chloride-vinyl acetate, such as nyl-vinyl acetate copolymer, hydroxy-modified vinyl chloride-vinyl acetate copolymer, carboxyl-modified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer Copolymer, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, styrene-alkyd resin, silicone-alkyd resin, phenol-formaldehyde resin and other insulating resins, poly-N-vinylcarbazole, polyvinylanthracene, It can be selected from organic photoconductive polymers such as polyvinyl perylene, but is not limited to these polymers. These binder resins may be used alone or in combination of two or more.

Solvents used for preparing the coating liquid and the dispersion medium for dissolving the binder resin, for example, saturated aliphatic solvents such as pentane, hexane, octane, and nonane,
Aromatic solvents such as toluene, xylene, anisole,
Halogenated aromatic solvents such as chlorobenzene, dichlorobenzene, chloronaphthalene,
Amide solvents such as dimethylformamide and N-methyl-2-pyrrolidone,
Alcohol solvents such as methanol, ethanol, isopropanol, n-butanol, benzyl alcohol,
Aliphatic polyhydric alcohols such as glycerin and polyethylene glycol,
Chain, branched and cyclic ketone solvents such as acetone, cyclohexanone, methyl ethyl ketone, 4-methoxy-4-methyl-2-pentanone,
Ester solvents such as methyl formate, ethyl acetate, n-butyl acetate,
Halogenated hydrocarbon solvents such as methylene chloride, chloroform, 1,2-dichloroethane,
Linear and cyclic ether solvents such as diethyl ether, dimethoxyethane, tetrahydrofuran, 1,4-dioxane, methyl cellosolve, ethyl cellosolve,
Aprotic polar solvents such as acetonitrile, dimethyl sulfoxide, sulfolane, hexamethylphosphoric triamide,
n-butylamine, isopropanolamine, diethylamine, triethanolamine, nitrogen-containing compounds such as ethylenediamine, triethylenediamine and triethylamine, mineral oil such as ligroin,
Examples thereof include water, and those that do not dissolve the undercoat layer described below are preferably used. These can be used alone or in combination of two or more.

  In the charge generation layer of the function-separated type photoreceptor, the compounding ratio (weight) of the binder resin and the charge generation material is 10 to 1000 parts by weight, preferably 30 parts by weight to 100 parts by weight of the binder resin. The thickness is in the range of 500 parts by weight, and the film thickness is usually 0.1 μm to 4 μm, preferably 0.15 μm to 0.6 μm. If the ratio of the charge generation material is too high, the stability of the coating solution is lowered due to problems such as aggregation of the charge generation material. On the other hand, if it is too low, the sensitivity as a photoreceptor is reduced. Is preferred. As a method for dispersing the charge generating substance, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, or a sand mill dispersion method can be used. In this case, it is effective to refine the particles to a particle size of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

<Charge transport material>
The photosensitive layer formed on the conductive support may have a single layer structure in which the charge generation material and the charge transport material are present in the same layer and dispersed in the binder resin, or the charge generation material may be The charge generation layer dispersed in the binder and the charge transport material may be any layered structure in which the charge transport material is functionally separated into the charge transport layer dispersed in the binder resin. And other components used accordingly. Specifically, the charge transport layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge transport material and a binder resin in a solvent. In the case of an inversely laminated photosensitive layer, it can be obtained by coating and drying on a conductive support (on the undercoat layer in the present invention in which an undercoat layer is provided).

Any known charge transport material can be used as the charge transport material. Examples of known charge transport materials include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron withdrawing materials such as quinone compounds such as diphenoquinone, and carbazole derivatives. , Indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives and multiple types of these compounds Or an electron donating substance such as a polymer having a group composed of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable. Any one of these charge transport materials may be used alone, or two or more thereof may be used in any combination.

  In the present invention, when an arylamine compound or a hydrazone compound is used, it is preferable in that the effect of the present invention appears greatly. Specific examples of suitable structures of the charge transport material are shown below. In the following compounds, R may be the same or different. Specifically, a hydrogen atom, an alkyl group, an alkoxy group, a phenyl group, an arylalkyl and the like are preferable. Particularly preferred is a methyl group, an ethyl group or a benzyl group. N is an integer of 0 to 2. These specific examples are shown for illustration, and any known charge transporting material may be used as long as it does not contradict the gist of the present invention.

<Binder resin>
In forming a charge transport layer of a function-separated type photoreceptor having a charge generation layer and a charge transport layer and a photosensitive layer of a single layer type photoreceptor, a binder resin is used to disperse the compound in order to ensure film strength. In the case of the charge transport layer of the functional separation type photoreceptor, a coating solution obtained by dissolving or dispersing the charge transport material and various binder resins in a solvent, and in the case of a single layer type photoreceptor, the charge generation material and the charge transport. It can be obtained by applying and drying a coating solution obtained by dissolving or dispersing the substance and various binder resins in a solvent. Examples of the binder resin include polymers and copolymers of vinyl compounds such as butadiene resin, styrene resin, vinyl acetate resin, vinyl chloride resin, acrylic ester resin, methacrylic ester resin, vinyl alcohol resin, ethyl vinyl ether, and polyvinyl butyral. Resin, polyvinyl formal resin, partially modified polyvinyl acetal, polycarbonate resin, polyester resin, polyarylate resin, polyamide resin, polyurethane resin, cellulose ester resin, phenoxy resin, silicone resin, silicone-alkyd resin, poly-N-vinylcarbazole resin, etc. Is mentioned. These resins may be modified with a silicon reagent or the like. Of the above binder resins, polycarbonate resins or polyarylate resins are preferred.

Among polycarbonate resins and polyarylate resins, bisphenol having the following structural formula, or polycarbonate resins and polyarylate resins containing a biphenol component are preferable in terms of sensitivity and residual potential, and in particular, polycarbonate resins are more preferable in terms of mobility. preferable.
The structure of bisphenol and biphenol that can be suitably used for the polycarbonate resin is exemplified below. This illustration is made for the purpose of clarifying the gist of the present invention, and is not limited to the illustrated structure unless it is contrary to the gist of the present invention.

  In particular, in order to maximize the effects of the present invention, a polycarbonate containing a bisphenol or biphenol component having the following structure is preferred.

The compound used in the present invention is contained in the photosensitive layer when the photoreceptor is a single layer type photoreceptor.
When the photoreceptor is a multilayer photoreceptor, it may be contained in any layer of the photosensitive layer, but the compound used in the present invention exhibits an effect by interacting with a charge transport material upon exposure to light. Therefore, when it is contained in the charge transport layer, the highest effect is obtained in preventing a large fluctuation in the residual potential upon exposure to light.

The amount of the compound used in the present invention represented by formula (1) or formula (2) is arbitrary, but it suppresses the deterioration of electrical characteristics immediately after exposure to external light and light fatigue, and has high sensitivity and residual potential. Is preferably 30 parts by weight or less, more preferably 100 parts by weight or less with respect to 100 parts by weight of the binder resin used in the layer containing the compound represented by formula (1) or (2). Is 25 parts by weight or less, more preferably 20 parts by weight or less, particularly preferably 15 parts by weight or less, preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, and still more preferably 0.5 parts by weight. Part by weight or more, particularly preferably 1 part by weight or more.

In addition, any one of the compounds used in the present invention may be used alone, or two or more may be used in any combination.
The ratio of the binder resin and the charge transport material used in the charge transport layer of the multilayer photoconductor and the photosensitive layer of the single layer photoconductor is usually charged to 100 parts by weight of the binder resin in both the single layer type and the multilayer type. The transport material is 20 parts by weight or more, preferably 30 parts by weight or more from the viewpoint of reducing the residual potential, and more preferably 40 parts by weight or more from the viewpoint of stability during repeated use and charge mobility. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, it is usually 150 parts by weight or less, preferably 120 parts by weight or less from the viewpoint of compatibility between the charge transport material and the binder resin, and 100 parts by weight from the viewpoint of printing durability. Part or less is more preferable, and 80 parts by weight or less is particularly preferable in terms of scratch resistance.

  In the case of a single-layer type photoreceptor, the charge generating substance is further dispersed in the charge transport medium having the above-described blending ratio. In this case, the particle size of the charge generating material needs to be sufficiently small, preferably 1 μm or less, more preferably 0.5 μm or less. If the amount of the charge generating material dispersed in the photosensitive layer is too small, sufficient sensitivity may not be obtained. On the other hand, if the amount is too large, adverse effects such as a decrease in chargeability and a decrease in sensitivity may occur. For example, it is preferably used in the range of 0.1 to 50% by mass, particularly preferably in the range of 1 to 20% by mass.

The film thickness of the photosensitive layer of the single-layer type photoreceptor is usually 5 to 100 μm, preferably 10 to 50 μm. The film thickness of the charge transport layer of the forward laminated photoreceptor is usually 5 to 50 μm. Although used, it is preferably 10 to 45 μm from the viewpoint of long life and image stability, and more preferably 10 to 30 μm from the viewpoint of high resolution.
The photosensitive layer has well-known antioxidants, plasticizers, ultraviolet absorbers, electron-withdrawing compounds to improve film-forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc. Further, additives such as a leveling agent and a visible light shading agent may be contained. In addition, the photosensitive layer may contain various additives such as a leveling agent, an antioxidant, and a sensitizer for improving the coating property as necessary. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds. Examples of surfactants include silicone oil and fluorine oil.

  A protective layer may be provided on the outermost surface layer of the photosensitive member for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to a discharge substance generated from a charger or the like. The protective layer is formed by containing a conductive material in a suitable binder resin, or a co-polymer using a compound having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004. Coalescence can be used. Examples of the conductive material include aromatic amino compounds such as TPD (N, N′-diphenyl-N, N′-bis- (m-tolyl) benzidine), antimony oxide, indium oxide, tin oxide, titanium oxide, and tin oxide. -Metal oxides such as antimony oxide, aluminum oxide, and zinc oxide can be used, but are not limited thereto.

As the binder resin used for the protective layer, known resins such as polyamide resin, polyurethane resin, polyester resin, epoxy resin, polyketone resin, polycarbonate resin, polyvinyl ketone resin, polystyrene resin, polyacrylamide resin, and siloxane resin can be used. Further, a copolymer of the above resin with a skeleton having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 can also be used. The protective layer is preferably configured to have an electric resistance of 10 ⁹ to 10 ¹⁴ Ω · cm. When the electric resistance is higher than 10 ¹⁴ Ω · cm, the residual potential is increased and an image with much fogging is formed. On the other hand, when the electric resistance is lower than 10 ⁹ Ω · cm, the image is blurred and the resolution is lowered. In addition, the protective layer must be configured so as not to substantially impede transmission of light irradiated for image exposure.

  In addition, fluorine resin, silicone resin, polyethylene resin, polystyrene resin, etc. are used for the surface layer for the purpose of reducing frictional resistance and abrasion on the surface of the photoconductor and increasing the transfer efficiency of the toner from the photoconductor to the transfer belt and paper. May be included. Moreover, the particle | grains which consist of these resin, and the particle | grains of an inorganic compound may be included.

<Layer formation method>
Each layer constituting the photoreceptor is formed by sequentially applying a coating solution containing the material constituting each layer on the support using a known coating method and repeating the coating and drying process for each layer. The
In the case of the charge transport layer of the single layer type photoreceptor and the multilayer type photoreceptor, the coating solution for forming the layer is usually used in a solid content concentration of 5 to 40% by mass, but 10 to 35% by mass. It is preferable to use in the range. Moreover, although the viscosity of this coating liquid is normally used in the range of 10-500 mPa * s, it is preferable to set it as the range of 50-400 mPa * s.
In the case of the charge generating layer of the multilayer photoreceptor, the solid content is usually used in the range of 0.1 to 15% by mass, but more preferably in the range of 1 to 10% by mass. Although the viscosity of a coating liquid is normally used in the range of 0.01-20 mPa * s, it is more preferable to be used in the range of 0.1-10 mPa * s.

Examples of the coating method include a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a wire bar coating method, a blade coating method, a roller coating method, an air knife coating method, and a curtain coating method. Other known coating methods can also be used.
The coating solution is preferably dried by touching at room temperature and then heating and drying in a temperature range of 30 to 200 ° C. for 1 minute to 2 hours with no air or air. The heating temperature may be constant or may be changed while drying.

<Image forming apparatus>
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described with reference to FIG. However, the embodiment is not limited to the following description, and can be arbitrarily modified without departing from the gist of the present invention.
As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, a developing device 4, and a transfer device 5, and further includes a cleaning device 6 and a fixing device as necessary. A device 7 is provided.

The electrophotographic photoreceptor 1 is not particularly limited as long as it is the above-described electrophotographic photoreceptor of the present invention, but in FIG. 1, as an example, a drum in which the above-described photosensitive layer is formed on the surface of a cylindrical conductive support. The photoconductor is shown. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are disposed along the outer peripheral surface of the electrophotographic photosensitive member 1.
The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 1, a roller type charging device (charging roller) is shown as an example of the charging device 2, but a corona charging device such as a corotron or a scorotron, a contact type charging device such as a charging brush, etc. are often used.

In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are designed to be removable from the main body of the image forming apparatus as a cartridge having both of them (hereinafter referred to as a photosensitive cartridge as appropriate). It is preferable to use in such a form.
In the present invention, as described above, this configuration is preferable in that the effect is remarkably exhibited when the charging unit is disposed in contact with the electrophotographic photosensitive member.

  For example, when the electrophotographic photoreceptor 1 or the charging device 2 deteriorates, the photoreceptor cartridge can be removed from the image forming apparatus main body, and another new photosensitive cartridge can be mounted on the image forming apparatus main body. ing. Also, the toner described later is often stored in the toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is removed. It can be removed from the main body of the image forming apparatus and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light having a wavelength of 780 nm, monochromatic light having a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light having a short wavelength of 380 nm to 600 nm. . However, the wavelength is preferably 600 nm to 800 nm, more preferably monochromatic light having a wavelength of 700 nm to 800 nm, and particularly preferably monochromatic light having a wavelength of 780 nm.

  The type of the developing device 4 is not particularly limited, and any device such as a dry development method such as cascade development, one-component conductive toner development, two-component magnetic brush development, or a wet development method can be used. In FIG. 1, the developing device 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45, and is configured to store toner T inside the developing tank 41. Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing device 4 as necessary. This replenishing device is configured to be able to replenish toner T from a container such as a bottle or a cartridge.

The supply roller 43 is formed from a conductive sponge or the like. The developing roller 44 is made of a metal roll such as iron, stainless steel, aluminum, or nickel, or a resin roll obtained by coating such a metal roll with a silicone resin, a urethane resin, a fluororesin, or the like. The surface of the developing roller 44 may be smoothed or roughened as necessary.
The developing roller 44 is disposed between the electrophotographic photoreceptor 1 and the supply roller 43 and is in contact with the electrophotographic photoreceptor 1 and the supply roller 43, respectively. The supply roller 43 and the developing roller 44 are rotated by a rotation drive mechanism (not shown). The supply roller 43 carries the stored toner T and supplies it to the developing roller 44. The developing roller 44 carries the toner T supplied by the supply roller 43 and contacts the surface of the electrophotographic photosensitive member 1.

  The regulating member 45 is formed of a resin blade such as a silicone resin or a urethane resin, a metal blade such as stainless steel, aluminum, copper, brass, phosphor bronze, or a blade obtained by coating the metal blade with a resin. The regulating member 45 contacts the developing roller 44 and is pressed against the developing roller 44 side with a predetermined force by a spring or the like (a general blade linear pressure is 5 to 500 g / cm). If necessary, the regulating member 45 may be provided with a function of imparting charging to the toner T by frictional charging with the toner T.

The agitator 42 is rotated by a rotation driving mechanism, and agitates the toner T and conveys the toner T to the supply roller 43 side. A plurality of agitators 42 may be provided with different blade shapes and sizes.
The type of the toner T is arbitrary, and in addition to the powdery toner, a polymerized toner using a suspension polymerization method, an emulsion polymerization method, or the like can be used. In particular, when a polymerized toner is used, a toner having a small particle diameter of about 4 to 8 μm is preferable, and the toner particles are used in various shapes ranging from a nearly spherical shape to a shape outside the spherical shape on the potato. be able to. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, it is assumed that the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like that are disposed to face the electrophotographic photoreceptor 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner T, and transfers the toner image formed on the electrophotographic photosensitive member 1 to a transfer material (paper, medium) P. Is. The present invention is effective when the transfer device 55 is placed in contact with the photoreceptor via a transfer material.

  There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner. However, when there is little or almost no toner remaining on the surface of the photoreceptor, the cleaning device 6 may be omitted.

  The fixing device 7 includes an upper fixing member (fixing roller) 71 and a lower fixing member (fixing roller) 72, and a heating device 73 is provided inside the fixing member 71 or 72. FIG. 1 shows an example in which a heating device 73 is provided inside the upper fixing member 71. As the upper and lower fixing members 71 and 72, known heat fixing members such as a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicone rubber, a fixing roll or a fixing sheet coated with a fluororesin, and the like are used. be able to. Further, the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve the releasability, or may be configured to forcibly apply pressure to each other by a spring or the like.

  When the toner transferred onto the recording paper P passes between the upper fixing member 71 and the lower fixing member 72 heated to a predetermined temperature, the toner is heated to a molten state and cooled after passing through the recording paper. Toner is fixed on P. The type of the fixing device is not particularly limited, and a fixing device of an arbitrary method such as heat roller fixing, flash fixing, oven fixing, pressure fixing, or the like can be provided.

<Image forming method>
In the electrophotographic apparatus configured as described above, an image is recorded as follows. That is, first, the surface (photosensitive surface) of the photoreceptor 1 is charged to a predetermined potential (for example, −600 V) by the charging device 2. At this time, charging may be performed with a DC voltage, or charging may be performed by superimposing an AC voltage on the DC voltage.

  Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1. The developing device 4 thins the toner T supplied by the supply roller 43 with a regulating member (developing blade) 45 and has a predetermined polarity (here, the same polarity as the charging potential of the photosensitive member 1) and the negative polarity. ), And conveyed while being carried on the developing roller 44 to be brought into contact with the surface of the photoreceptor 1.

When the charged toner T carried on the developing roller 44 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.
After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the fixing device 7 and thermally fixing the toner image onto the recording paper P. In addition to the above-described configuration, the image forming apparatus may be configured to perform, for example, a static elimination process. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of exposure light.

  The image forming apparatus may be further modified. For example, the image forming apparatus may be configured to perform a pre-exposure process, an auxiliary charging process, or the like, or may be configured to perform offset printing. A full-color tandem system configuration using toner may be used.

  Hereinafter, the present invention will be described more specifically with reference to examples, comparative examples, and reference examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded. Moreover, the description of “parts” in the following examples, comparative examples and reference examples indicates “parts by weight” unless otherwise specified.

Example 1
High-speed fluidized mixing of rutile type titanium oxide having an average primary particle diameter of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) The surface-treated titanium oxide obtained by mixing in a kneading machine (“SMG300” manufactured by Kawata Co., Ltd.) and mixing at high speed at a rotational peripheral speed of 34.5 m / sec is a weight ratio of methanol / 1-propanol of 7 / A dispersion slurry of hydrophobized titanium oxide was obtained by dispersing with a ball mill in the mixed solvent No. 3. The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-) described in Examples of JP-A-4-31870 Amino-3-methylcyclohexyl) methane [compound represented by the following formula (B)] / hexamethylenediamine [compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / Octadecamethylenedicarboxylic acid [compound represented by the following formula (E)] is stirred while heating the copolyamide pellets having a composition molar ratio of 60% / 15% / 5% / 15% / 5%. After mixing and dissolving the polyamide pellets, an ultrasonic dispersion treatment is performed, so that the weight of methanol / 1-propanol / toluene is increased. Ratio is 7/1/2, containing a hydrophobic-treated titanium oxide / copolymerized polyamide at a weight ratio of 3/1, to prepare a solid concentration of 18.0% of the undercoat layer dispersion liquid A.

Using a film obtained by depositing aluminum on a 75 μm thick polyester film as a support, the undercoat layer forming dispersion A is applied with a wire bar so that the dried film thickness becomes 1.5 μm, An undercoat layer was provided.
Next, as a charge generation material, 20 parts of oxytitanium phthalocyanine represented by the X-ray diffraction spectrum of FIG. 2 and 280 parts of 1,2-dimethoxyethane are mixed and pulverized in a sand grind mill for 2 hours to be atomized and dispersed. Was done. Subsequently, 10 parts of polyvinyl butyral (trade name “Denka Butyral” # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to 255 parts of 1,2-dimethoxyethane and 4-methoxy-4-methyl. A dispersion (for charge generation layer) was prepared by mixing a binder solution obtained by dissolving in 85 parts of a mixture of 2-pentanone and 230 parts of 1,2-dimethoxyethane. On the film provided with the undercoat layer, the charge generation layer coating solution was applied with a wire bar so that the film thickness after drying was 0.4 μm and dried to form a charge generation layer.

  Next, a polycarbonate (PC-1: viscosity average molecular weight of about 30,000; m: n = 1: 1) 100 having 70 parts of the following compound CT-1 as a charge transport material and a repeating unit having the following structure as a binder resin 100 Part,

  16 parts of an antioxidant represented by the following formula,

A solution obtained by dissolving 1 part of Exemplified Compound 92 and 0.05 part of silicone oil (trade name: KF96 Shin-Etsu Chemical Co., Ltd.) as a leveling agent in 640 parts of a tetrahydrofuran / toluene (8/2) mixed solvent is used as described above. On the charge generation layer, an electrophotographic photosensitive member E1 having a laminated photosensitive layer was obtained by coating so that the film thickness after drying was 25 μm.
Example 2
An electrophotographic photoreceptor E2 was obtained in the same manner as in Example 1 except that the exemplified compound 95 was used instead of the exemplified compound 92.

Example 3
An electrophotographic photoreceptor E3 was obtained in the same manner as in Example 1 except that the exemplified compound 121 was used instead of the exemplified compound 92.
Example 4
An electrophotographic photoreceptor E4 was obtained in the same manner as in Example 1 except that the exemplified compound 152 was used instead of the exemplified compound 92.

Example 5
An electrophotographic photoreceptor E5 was obtained in the same manner as in Example 1 except that the exemplified compound 114 was used instead of the exemplified compound 92.
Reference example 1
An electrophotographic photoreceptor E6 was obtained in the same manner as in Example 1 except that the exemplified compound 61 was used instead of the exemplified compound 92.

Reference example 2
An electrophotographic photoreceptor E7 was obtained in the same manner as in Example 1 except that the exemplified compound 53 was used instead of the exemplified compound 92.
Reference example 3
An electrophotographic photoreceptor E8 was obtained in the same manner as in Example 1 except that the exemplified compound 35 was used instead of the exemplified compound 92.

Reference example 4
An electrophotographic photoreceptor E9 was obtained in the same manner as in Example 1 except that the exemplified compound 27 was used instead of the exemplified compound 92.
Example 10
An electrophotographic photoreceptor E10 was obtained in the same manner as in Example 1 except that the exemplified compound 11 was used instead of the exemplified compound 92.

Comparative Example 1
An electrophotographic photoreceptor P1 was obtained in the same manner as in Example 1 except that the exemplified compound 92 was not used.
Comparative Example 2
Instead of using the compound of the exemplary compound 92, an electrophotographic photoreceptor P2 was obtained in the same manner as in Example 1 except that the following comparative compound A was used.

Comparative Example 3
An electrophotographic photosensitive member P3 was obtained in the same manner as in Example 1 except that the following comparative compound B was used instead of the exemplified compound 92.

Example 11
On the undercoat layer and the charge generation layer formed in the same manner as in Example 1, a charge transport layer coating solution shown below was applied to provide a 24 μm charge transport layer, and an electrophotographic photoreceptor E11 having a laminated photosensitive layer was prepared. Obtained.
Charge transport layer coating solution: Polycarbonate having 40 parts of the following compound CT-2 and 30 parts of CT-3 as a charge transport material and repeating unit of the following structure as a binder resin (PC-2: viscosity average molecular weight of about 40,000) 100 copies,

8 parts of an antioxidant having the following structure:

2 parts of Exemplified Compound 92 and 0.05 part of silicone oil (trade name KF96 Shin-Etsu Chemical Co., Ltd.) as a leveling agent are dissolved in 640 parts of a mixed solvent of tetrahydrofuran / toluene = 8/2 (weight ratio). A charge transport layer coating solution was prepared.
Example 12
An electrophotographic photoreceptor E12 was obtained in the same manner as in Example 11 except that the exemplified compound 95 was used instead of the exemplified compound 92.

Example 13
An electrophotographic photoreceptor E13 was obtained in the same manner as in Example 11 except that the exemplified compound 121 was used instead of the exemplified compound 92.
Example 14
An electrophotographic photoreceptor E14 was obtained in the same manner as in Example 11 except that the exemplified compound 152 was used instead of the exemplified compound 92.

Comparative Example 5
An electrophotographic photosensitive member P5 was obtained in the same manner as in Example 5 except that the exemplified compound 92 was not used as the compound having a sulfur acid derivative structure.
Comparative Example 6
An electrophotographic photosensitive member P6 was obtained in the same manner as in Example 5 except that the comparative compound A used in Comparative Example 2 was used instead of using the compound of Exemplary Compound 92.

<Evaluation of electrical characteristics and light resistance-1>
The electrophotographic photosensitive member produced in the examples and comparative examples was prepared by electrophotographic characteristic evaluation apparatus produced in accordance with the standard of the electrophotographic society (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404-405). In accordance with the following procedure, the electrical characteristics were evaluated by a cycle of charging (negative polarity), exposure, potential measurement, and static elimination.

Using a charger set so that the initial surface potential (−V0) of the photoconductor is −700 V, each photoconductor is charged to −700 V (V0 = 700), and the light of the halogen lamp is filtered by an interference filter. Exposure light (monochromatic light of 780 nm) was irradiated, and irradiation energy (half exposure energy) required for the surface potential to be −350 V was measured as sensitivity (E1 / 2) (unit “μJ / cm ² ”). . Further, the post-exposure surface potential (VL1) after 100 ms when the exposure light was irradiated at an intensity of 0.8 μJ / cm ² was measured (unit “−V”). Further, after setting the initial surface potential to −700 V, the surface potential after being left in a dark place for 5 seconds was measured, and the difference was defined as dark decay (DD). These results are summarized in Table 2 below.

  As can be seen from the electrophotographic photoreceptors of Examples 1 to 10 and Examples 11 to 14 compared with Comparative Examples 1 and 5, the electrical characteristics are deteriorated by the addition of the compound that can be used in the present invention. Absent.

<Strong light performance test-1>
Subsequently, light of a white fluorescent lamp (Neolmi Super FK20SS / W / 18 manufactured by Mitsubishi OSRAM Co., Ltd.) was applied to the obtained electrophotographic photoreceptor (except for P4 whose electrical characteristics were particularly bad). After adjusting for light intensity at 2000 lux (lx) and irradiating for 10 minutes (hereinafter abbreviated as “after intense light irradiation”), the same as above <Evaluation of electrical characteristics and light resistance-1> Then, VL1 (unit “−V”) was measured. The value of “VL1 (after intense light irradiation) −VL1 (before intense light irradiation)” is set to “ΔVL” (unit “−V”).

  The obtained electrophotographic photosensitive member was irradiated with intense light, and then a charger set in the same manner as in the above <Evaluation of electrical characteristics and light resistance-1> (that is, initial surface potential of the photosensitive member before intense exposure irradiation ( Each photoconductor was charged using a charger set so that -V0) would be -700V. When V0 at the initial surface potential (−V0) of the photoconductor after intense light irradiation is “V0 (after intense light irradiation)”, “ΔV0” is defined as follows.

ΔV0 = V0 (after intense light irradiation) −V0 (before intense light irradiation)
= V0 (after intense light irradiation) -700
For example, in the case of Example 3 in Table 3 below, the surface potential of the photoconductor after intense light irradiation is −689 [V], so that V0 (after intense light irradiation) = 689 [V].
ΔV0 = 689−700
= -11 [V]
It becomes.

  Each value indicates that the electrophotographic photosensitive member having a smaller amount of change has a smaller characteristic change even when exposed to strong light, and that the electric light resistance of the photosensitive member is excellent in strong light resistance. .

  As described above, a photoreceptor having a photosensitive layer containing a compound that can be used in the present invention has good balance of sensitivity, electrical characteristics represented by VL1 and DD, and is exposed to strong light. Even in this case, the absolute values of ΔV0 and ΔVL (immediately after the intense light irradiation) were small and the balance was good and good as compared with the photoconductor of the comparative example.

<Image evaluation test>
Example 15
The coating solution for the charge generation layer and the charge transport layer prepared in the same manner as in Example 1 is sequentially applied by dip coating on an aluminum tube having a diameter of 3 cm and a length of 25.4 cm that has been anodized and sealed. Then, by drying at 125 ° C. for 20 minutes, an electrophotographic photosensitive drum having a charge generation layer of 0.3 μm and a charge transport layer of 25 μm was prepared. This electrophotographic photosensitive drum is covered with black paper with a hole of 2cm in length and 4cm in width, and light from a white fluorescent lamp (Neolmi Super FK20SS / W / 18 manufactured by Mitsubishi OSRAM) from above the hole in the black paper. Was irradiated for 10 minutes while adjusting the light intensity on the surface of the electrophotographic photosensitive member to 2000 lux (lx). When this drum is mounted on a cartridge of Hured Packard's laser printer, laser jet 4 (LJ4), and a halftone image is printed out, an image test is performed. No image defect was observed, and a good image with less noise was obtained.

Comparative Example 7
Evaluation was conducted in the same manner as in Example 15 except that the coating solution for charge generation layer and charge transport layer in Example 15 was changed to that prepared in Comparative Example 1. As a result, the obtained image was a defective image having white spots in the drum cycle at the portion exposed by the light of the white fluorescent lamp.
Comparative Example 8
Evaluation was performed in the same manner as in Example 15 except that the coating solution for charge generation layer and charge transport layer in Example 15 was changed to that prepared in Comparative Example 2. As a result, the obtained image was a defect image having a black belt in the drum cycle in the portion exposed by the light of the white fluorescent lamp.

  The electrophotographic photoreceptor of the present invention has suitable electrical characteristics, can form a good image even when used repeatedly for a long time, is resistant to light fatigue, and has high image quality even under various use environments. Therefore, it is widely used in the fields of printers, FAX machines, copiers, and the like.

1 Photoconductor 2 Charging device (charging roller)
DESCRIPTION OF SYMBOLS 3 Exposure apparatus 4 Developing apparatus 5 Transfer apparatus 6 Cleaning apparatus 7 Fixing apparatus 41 Developing tank 42 Agitator 43 Supply roller 44 Developing roller 45 Control member 71 Upper fixing member (pressure roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper

Claims (5)

An electrophotographic photosensitive member having a photosensitive layer on a conductive support, wherein the photosensitive layer contains a compound represented by the following formula (2).

(In the formula (2), X is an organic group having 30 or less of _{n 3} valent carbon, Y represents a monovalent organic group, Z is an organic group having 15 or less of _n 2 +1 divalent carbon below 15 carbon atoms N ₂ represents an integer of 1 to 10, and n ₃ represents an integer of 1 to 10.   X is an organic group having at least one group selected from an aromatic group which may have a substituent and a condensed polycyclic group which may have a substituent, Item 2. The electrophotographic photosensitive member according to Item 1.   The electrophotographic photosensitive member according to claim 2, wherein X has 4 or less ring structures.   A process cartridge on which the electrophotographic photosensitive member according to claim 1 is mounted.   An electrophotographic photosensitive member; a charging unit that charges the photosensitive member; an image exposing unit that performs image exposure on the charged photosensitive member to form an electrostatic latent image; and development that develops the electrostatic latent image with toner An image forming apparatus comprising: a transfer unit configured to transfer a toner to a transfer target; wherein the photosensitive member according to claim 1 is used as the photosensitive member. An image forming apparatus.

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