JP6497092B2 - Electrophotographic photoreceptor, electrophotographic cartridge, image forming apparatus, method for producing electrophotographic photoreceptor, and charge transport material - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member that does not cause white spots even when used repeatedly in a high-temperature and high-humidity environment in a full-color image forming apparatus.

  In recent years, electrophotographic technology has been widely used and applied not only in the field of copying machines but also in the field of various printers because of its immediacy and high quality images. As for photoconductors that are the core of electrophotographic technology, in recent years, photoconductors using organic photoconductive materials that have advantages such as non-polluting, easy film formation, and easy manufacture are available. Has been developed.

  In recent years, both copying machines and printers using electrophotographic technology are moving from monochrome to full color. This full-color image forming method mainly includes a tandem method and a four-cycle method, and a transfer method to a printing medium includes a direct transfer method, a transfer drum method, an intermediate transfer method, a multiple development batch transfer method, and the like. Unlike a monochrome image forming apparatus, a full-color image forming apparatus has a very high level of required image quality. In such a flow, there is a demand for a photoreceptor that can maintain high image quality even when subjected to excessive stress under a special environment (for example, high temperature and high humidity).

  The contribution of the charge transport material is significant in determining the image quality of the photoreceptor. As a charge transport material, various materials such as a carbazole derivative, a hydrazone derivative, a stilbene derivative, a butadiene derivative, and an enamine derivative have been put into practical use. For example, it has been proposed to use a highly sensitive triarylamine-stilbene hybrid type compound as a charge transport material for an electrophotographic photoreceptor (Patent Document 1).

Japanese Patent Laid-Open No. 9-292724

  However, even when a triarylamine-stilbene hybrid type compound is used, there is a problem that high image quality cannot be maintained when excessive stress is applied. Under such circumstances, white spots occur when repeatedly used under high temperature and high humidity, which is particularly problematic in the case of a full-color image forming apparatus. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for producing an electrophotographic photosensitive member that does not cause white spots even when used repeatedly in a high-color and high-humidity environment in a full-color image forming apparatus. An object is to provide a photoconductor, an electrophotographic cartridge, and an image forming apparatus.

As a result of intensive studies, the present inventor has produced a photoconductor using a specific charge transporting material by a specific manufacturing method or using a photoconductor using a specific charge transporting material, thereby increasing the temperature and humidity. The inventors have found that it is possible to provide a good image quality that does not cause white spots even when repeatedly used below, and have completed the present invention described below. The gist of the present invention resides in the following <1> to <11>.
<1> In an electrophotographic photosensitive member having a photosensitive layer on a conductive support, the photosensitive layer contains a compound represented by the general formula (1) and palladium, and the palladium content in the photosensitive layer is 0.00.
An electrophotographic photoreceptor having a content of from 01 to 50 ppm.

(In Formula (1), Ar < ¹ > -Ar < ⁵ > represents the aryl group which may each independently have a substituent, and Ar < ⁶ > -Ar < ⁹ > may each independently have a substituent. Represents a 1,4-phenylene group, and m and n each independently represents an integer of 1 to 3.

<2> In an electrophotographic photoreceptor having a photosensitive layer containing a charge transport material on a conductive support, the charge transport material contains the compound represented by the general formula (1) and palladium, and the charge transport An electrophotographic photoreceptor, wherein a palladium content in the substance is 0.01 to 150 ppm.
<3> The compound represented by the formula (1) contained in the photosensitive layer is 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the binder resin forming the photosensitive layer. <1> or <2>, wherein the electrophotographic photosensitive member is characterized.

<4> In the formula (1), Ar ^{1 to} Ar ⁵ are each independently an aryl group optionally having an alkyl group or an alkoxy group, and Ar ^{6 to} Ar ⁹ are each independently having a substituent. The electrophotographic photosensitive member according to any one of <1> to <3>, wherein 1,4-phenylene group, m and n may be 1.

<5> The electrophotographic photosensitive material according to any one of <1> to <4>, wherein the photosensitive layer contains a binder resin, and the binder resin is a polyarylate resin or a polycarbonate resin. body.
<6> The electrophotographic photosensitive member according to any one of <1> to <5>, wherein the compound represented by the formula (1) is purified using an adsorbent.

<7> The electrophotographic photosensitive member according to any one of <1> to <6>, which is used in a full-color image forming apparatus.
<8> The electrophotographic photosensitive member according to any one of <1> to <7>, a charging device that charges the electrophotographic photosensitive member, and an electrostatic latent image formed by exposing the charged electrophotographic photosensitive member An electrophotographic photosensitive member cartridge comprising at least one selected from the group consisting of an exposure device for forming a developing device and a developing device for developing an electrostatic latent image formed on the electrophotographic photosensitive member.

<9> The electrophotographic photosensitive member according to any one of <1> to <7>, a charging device for charging the electrophotographic photosensitive member, and forming an electrostatic latent image by exposing the charged electrophotographic photosensitive member. A full-color image forming apparatus, comprising: an exposure apparatus for developing the image forming apparatus; and a developing apparatus for developing an electrostatic latent image formed on the electrophotographic photosensitive member.
<10> A charge transporting material containing the compound represented by the general formula (1) and palladium, wherein the charge transporting material has a palladium content of 0.01 to 150 ppm. .

<11> In a method for producing an electrophotographic photosensitive member having a photosensitive layer containing the charge transport material represented by the above formula (1) on a conductive support, after synthesizing using a palladium compound, the palladium content is A method for producing an electrophotographic photosensitive member, comprising forming a photosensitive layer using an organic solvent containing the charge transport material purified to 0.1 to 150 ppm and a binder resin.

  The present invention can provide an electrophotographic photosensitive member that does not cause white spots when repeatedly used in a high-temperature and high-humidity environment even in a full-color image forming apparatus.

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

  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.

≪Charge transport material≫
<Structure of charge transport material>
The charge transport material of the present invention may contain any compound represented by the following general formula (1) and palladium, as long as the palladium content is 0.01 to 150 ppm.

(Formula (1) Ar ^{1 to} Ar ⁵ each independently represents an aryl group which may have a substituent, and Ar ^{6 to} Ar ⁹ may each independently have a substituent. Represents a 4-phenylene group, and m and n each independently represents an integer of 1 to 3.

In the above formula (1), Ar ^{1 to} Ar ⁵ each independently represents an aryl group which may have a substituent. The number of carbon atoms of the aryl group is 30 or less, preferably 20 or less, more preferably 15 or less. Specific examples include a phenyl group, a naphthyl group, a biphenyl group, an anthryl group, and a phenanthryl group. Among these, in consideration of the characteristics of the electrophotographic photosensitive member, a phenyl group, a naphthyl group, and an anthryl group are preferable. From the viewpoint of charge transport capability, a phenyl group and a naphthyl group are more preferable, and a phenyl group is further preferable.

Examples of the substituent that Ar ^{1 to} Ar ⁵ may have include an alkyl group, an alkoxy group, an aryl group, and a halogen atom. Specifically, as the alkyl group, a linear alkyl group such as a methyl group, an ethyl group, an n-propyl group or an n-butyl group, a branched alkyl group such as an isopropyl group or an ethylhexyl group, or a cyclic group such as a cyclohexyl group. An alkyl group is mentioned. Examples of the aryl group include an optionally substituted phenyl group and naphthyl group. Examples of the alkoxy group include linear alkoxy groups such as methoxy group, ethoxy group, n-propoxy group and n-butoxy group, branched alkoxy groups such as isopropoxy group and ethylhexyloxy group, and cyclic alkoxy groups such as cyclohexyloxy group. And alkoxy groups having a fluorine atom such as a group, a trifluoromethoxy group, a pentafluoroethoxy group, and a 1,1,1-trifluoroethoxy group. Examples of the halogen atom include a fluorine atom, a chlorine atom and a bromine atom. Among these, an alkyl group having 1 to 20 carbon atoms and an alkoxy group having 1 to 20 carbon atoms are preferable from the versatility of production raw materials, and an alkyl group having 1 to 12 carbon atoms and carbon number from the viewpoint of handleability during production. An alkoxy group having 1 to 12 carbon atoms is more preferable, and an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms are more preferable from the viewpoint of light attenuation characteristics as an electrophotographic photoreceptor. In the case where Ar ^{1 to} Ar ⁵ are phenyl groups, it is preferable to have a substituent from the viewpoint of charge transport ability, and the number of substituents can be 1 to 5, but from the versatility of manufacturing raw materials, 1 1 to 3 are preferable, and from the viewpoint of the characteristics of the electrophotographic photosensitive member, 1 to 2 are more preferable, and when Ar ^{1 to} Ar ⁵ are naphthyl groups, the number of substituents from the versatility of the production raw material Is preferably 2 or less or not having a substituent, and more preferably, the number of substituents is 1 or having no substituent. Ar ¹ preferably has at least one substituent in the ortho-position or para-position relative to the nitrogen atom. As the substituent, from the viewpoint of solubility, the alkoxy group having 1 to 6 carbon atoms or 1 to 6 carbon atoms is preferable. Are preferred.

In the above formula (1), Ar ^{6 to} Ar ⁹ each independently represents a 1,4-phenylene group which may have a substituent. As the substituent that Ar ^{6 to} Ar ⁹ may have, those exemplified as the substituent that Ar ^{1 to} Ar ⁵ may have are applicable. Among these, a C1-C6 alkyl group and a C1-C6 alkoxy group are preferable from the versatility of a manufacturing raw material, and a C1-C4 alkyl group and carbon number from the surface of the handling property at the time of manufacture 1-4 alkoxy groups are more preferable, and a methyl group, an ethyl group, a methoxy group, and an ethoxy group are more preferable from the viewpoint of light attenuation characteristics as an electrophotographic photosensitive member. When Ar ^{6 to} Ar ⁹ have a substituent, the molecular structure is twisted, and π-conjugate expansion in the molecule may be hindered, and the electron transport ability may be reduced. Therefore, Ar ^{6 to} Ar ⁹ may be substituted. It is preferable not to have.

  m and n each independently represent an integer of 1 to 3. When m and n are large, the solubility in a coating solvent tends to decrease. Therefore, it is preferably 2 or less, and more preferably 1 from the viewpoint of charge transport ability as a charge transport material. When m and n are 1, it represents an ethenyl group and has a geometric isomer, but from the viewpoint of electrophotographic photoreceptor characteristics, a trans isomer structure is preferred. When m and n are 2, it represents a butadienyl group, which also has a geometric isomer, but is preferably a mixture of two or more geometric isomers from the viewpoint of coating solution storage stability.

The electrophotographic photoreceptor of the present invention may contain the compound represented by the formula (1) as a single component in the photosensitive layer, or may contain it as a mixture of the compounds represented by the formula (1). Is possible.
As the charge transport material, a compound represented by the following formula (1a) is particularly preferable from the viewpoint of electrical characteristics. In formula (1a), Ar ¹ in formula (1) is a phenyl group having an alkyl group, an alkoxy group, an aryloxy group, or an aralkyloxy group, and Ar ^{2 to} Ar ⁵ are each independently a substituent. It is a phenyl group which may have an alkyl group having 1 to 6 carbon atoms, Ar ^{6 to} Ar ⁹ are all unsubstituted 1,4-phenylene groups, and m and n are both 1.

(In formula (1a), R ^{a to} R ^e each independently represents an alkyl group, an alkoxy group, an aryloxy group, an aralkyloxy group, or a hydrogen atom.)
Examples of the structure of the compound charge transport material suitable for the present invention are shown below. The following structures are illustrated to make the present invention more concrete, and are not limited to the following structures unless departing from the concept of the present invention.

The ratio of the binder resin in the photosensitive layer to the charge transport material containing the compound represented by the formula (1) is usually 15 masses of the charge transport material with respect to 100 parts by mass of the binder resin in the same layer. Use more than one part. 20 parts by mass or more is preferable from the viewpoint of residual potential reduction, and 25 parts by mass or more is more preferable from the viewpoint of stability and charge mobility when repeatedly used. On the other hand, from the viewpoint of thermal stability of the photosensitive layer, the charge transport material is usually used in an amount of 70 parts by mass or less. 65 parts by mass or less is preferable from the viewpoint of compatibility between the charge transporting material containing the compound represented by the formula (1) and the binder resin, 60 parts by mass or less is more preferable from the viewpoint of heat resistance, and from the viewpoint of scratch resistance. The amount is preferably 50 parts by mass or less, and particularly preferably 45 parts by mass or less from the viewpoint of wear resistance. The structure of the charge transport material suitable for the present invention is exemplified below. The following structures are illustrated to make the present invention more concrete, and are not limited to the following structures unless departing from the concept of the present invention.

<Method for producing charge transport material>
In the method for producing the charge transport material represented by the general formula (1), the step of synthesizing the charge transport material using a palladium compound, and the palladium content of the charge transport material using an adsorbent is 0.1 to A method for producing a charge transport material having a step of purification to 150 ppm is preferred.

(Process to synthesize)
The exemplified charge transport material can be produced according to Scheme 1 below. Taking the above compound as an example, it is possible to synthesize a crude product before purification by performing a coupling reaction using a triphenylamine derivative having a halogen atom and an aniline compound as a palladium compound as a catalyst. .

(In the above formula, X represents a halogen atom.)
Examples of the palladium compound include tetravalent palladium compounds such as sodium hexachloropalladate tetrahydrate and potassium hexachloropalladate tetrahydrate, palladium acetate, palladium chloride, palladium bromide, palladium acetyl acetate, dichlorobis (benzonitrile) palladium, Divalent palladium compounds such as dichlorobis (triphenylphosphine) palladium, dichlorotetraminepalladium and dichloro (cycloocta-1,5-diene) palladium, tris (dibenzylideneacetone) dipalladium, tris (dibenzylideneacetone) dipalladium chloroform complex And palladium compounds such as tetrakis (triphenylphosphine) palladium and allylpalladium (II) chloride dimer. Among these, from the viewpoint of yield, palladium acetate and allyl palladium (II) chloride dimer which are divalent palladium compounds are preferable.

  It is also possible to carry out a coupling reaction in the presence of a compound serving as a ligand together with the compound. The compound serving as a ligand is preferably a phosphorus compound. Specific examples include phosphine compounds, phosphite compounds, phosphoramidite compounds, and triaminophosphine compounds. Among these, a phosphine compound is preferable from the viewpoint of yield. Examples of the phosphine compound include alkylphosphine derivatives such as tricyclohexylphosphine and tri-tert-butylphosphine, and arylphosphine derivatives such as phenylphosphine and tri-o-tolylphosphine. Among these, alkylphosphine derivatives are preferable from the viewpoint of yield.

From the viewpoint of yield, the lower limit of the amount of the palladium compound used in the coupling reaction is usually 0.0002 mol or more, preferably 0.0005 mol or more, more preferably 0 with respect to 1 mol of the triphenylamine derivative compound having a halogen atom. 0.001 mol or more. From the viewpoint of ease of purification, the upper limit is 10 mol or less, preferably 1 mol or less, more preferably 0.5 mol or less, and still more preferably 0.1 mol or less.

(Purification process)
The crude product synthesized in the above scheme 1 can be purified to a state having a specific palladium content that can be used for an electrophotographic photosensitive member by performing a purification treatment using an adsorbent.

  Any known adsorbent can be used for the purification method using the adsorbent, and specific examples of the adsorbent include activated carbon, silica gel, alumina, activated clay, florisil, diatomaceous earth, and the like. Among these, activated carbon, silica gel, activated clay, and florisil are preferable from the viewpoint of electrophotographic photoreceptor characteristics, and activated carbon, activated clay, and florisil are more preferable from the viewpoint of production cost, and more preferably activated clay and florisil.

  The purification process using an adsorbent is usually performed by dissolving a coarse charge transport material in an organic solvent and bringing the solution into contact with the adsorbent. The organic solvent that can be used for the purification treatment is not particularly limited as long as it is a solvent capable of dissolving the charge transport material, but in consideration of the adsorption / desorption equilibrium between the adsorbent and the charge transport material, the aliphatic hydrocarbon is used. A solvent or an aromatic hydrocarbon solvent is preferred.

  Preferable specific examples of the aromatic hydrocarbon solvent include benzene, toluene, o-xylene, m-xylene, p-xylene, o-cymene, m-cymene, p-cymene, anisole, ethyl xylene, ethyl toluene, ethyl Anisole, methylnaphthalene, diphenylmethane and the like can be mentioned, and preferred specific examples of the aliphatic hydrocarbon solvent include n-hexane, n-heptane, n-octane, n-decane, n-dodecane, and 2,3-dimethylhexane. , 2-methylheptane, 2-methylhexane, 3-methylhexane, cyclohexane and the like. Among the above solvents, an aromatic hydrocarbon solvent is preferable from the viewpoint of operability during production, an aromatic hydrocarbon solvent having a boiling point of 150 ° C. or less is preferable, toluene and xylene are more preferable, and toluene is more preferable. Any one of these solvents may be used as a single solvent, or any two or more of them may be used as a mixed solvent.

  The amount of the organic solvent used can be selected from various values depending on the solubility of the crude body. However, the mass ratio value of (crude body) / (organic solvent) determines the charge transport material productivity. From the viewpoint of the purification efficiency of the charge transport material, it is usually 0.5 or less, preferably 0.4 or less, more preferably 0.3 or less. is there.

  As the amount of adsorbent used, if the amount of adsorbent is too large relative to the rough body, it may adversely affect the hole transport ability of the charge transport material due to the decrease in purification yield due to poor filterability and the oxidizing ability of the adsorbent. The mass ratio of (adsorbent) / (coarse) is usually 1.5 or less, preferably 1.2 or less, more preferably 1.0 or less. On the other hand, the mass ratio is usually 0.001 or more, preferably 0.005 from the viewpoint of low degree of adverse effect of the oxidizing ability of the adsorbent on the arylamine compound, since the purification efficiency is lowered if the amount is too small. As described above, the range is more preferably 0.01 or more.

The charge transport material used in the present invention may be purified by adding another purification method to the purification method using the adsorbent and combining two or more purification methods. A specific example of another purification method combined with the purification method using an adsorbent is a reprecipitation method in which the solution is dissolved in a good solvent having a high affinity with the charge transport material, and after the solution is prepared, the solution is added to a poor solvent and solidified. Examples thereof include a crystallization method in which the solution is cooled by heating in a solvent having high affinity, and then the solution is cooled as it is, or a poor solvent is added to the solution and then cooled and aged to precipitate crystals. From the aspect of image quality at the time of image formation, it is preferable to purify using at least the adsorption method and one or more other purification methods, more preferably the combined use of the adsorption method and the reprecipitation method, and the combined use of the adsorption method and the crystallization method. .

  The palladium content in the charge transport material is 150 ppm or less, more preferably 120 ppm or less, and still more preferably 100 ppm or less from the viewpoint of electrical characteristics. From the viewpoint of reducing the purification load and the burden on the charge transport material due to purification, it is 0.01 ppm or more, more preferably 0.1 ppm or more, still more preferably 0.5 ppm or more, and even more preferably 1 ppm or more. The palladium content can be satisfied by combining the adsorbent, purification technique and conditions used.

  The purity of the charge transport material is preferably 97.0% or more, more preferably 97.5% or more, and further preferably 98.0% or more from the viewpoint of electrical characteristics. From the viewpoint of solubility, it is preferably 99.9% or less, more preferably 99.8% or less, and still more preferably 99.7% or less. As a method for achieving 97.0% or more, a production method in which a palladium compound is combined with a ligand having a phosphorus atom as a catalyst can be used. On the other hand, as a method for achieving 99.9% or less, there is a purification method such as a crystallization treatment. In order to make it 98.0% or more and 99.7% or less, it is preferable to purify by a method using an adsorbent.

When a charge transport material is produced using a palladium compound, a desired charge transport material can be produced with high efficiency, but the palladium used in the charge transport material remains. In addition to the palladium compound, the crude charge transport material before purification contains many impurities that affect the electrophotographic photoreceptor characteristics, such as a compound by-produced during the reaction.
When purifying a crude charge transport material produced using a palladium compound, it is preferable not to remove only the residual palladium compound, but at the same time to remove impurities that deteriorate the photoreceptor characteristics. It may be possible to enhance the purification so that all remaining palladium compounds and impurities generated during the reaction can be removed. However, if the purification is performed excessively, the structure of the charge transport material itself changes due to contact with the adsorbent. In some cases, the adverse effect may be greater than the purification effect. On the other hand, if the purification is insufficient, the adverse effect of the residual impurities will increase.

  In addition, the manner in which the electrophotographic photosensitive member exerts an adverse effect on stress such as transfer voltage received from the image forming apparatus varies greatly depending on the combination of the amount and type of impurities and the structure of the charge transport material. The amount and type of the compound / impurity that may remain depends on the structure of the target charge transport material. In particular, in the charge transport material, the residual palladium compound greatly affects the negative effect on the transfer voltage stress received from the image forming apparatus. Details of the mechanism are unknown, but a weak intermolecular force is likely to act between the charge transport material and the residual palladium compound, and a strong voltage can be applied from the image forming apparatus during the transfer process with this weak intermolecular force acting. As a result, it becomes easier to form charge trap sites in the photosensitive layer, and it is presumed that the formation image quality is adversely affected by the trap. Therefore, by performing the adsorbent treatment according to the present invention, while purifying to a specific palladium content, other impurities are removed, thereby adversely affecting stress such as transfer voltage from the image forming apparatus. It is possible to provide an electrophotographic photosensitive member that exhibits good characteristics without being expressed.

  The charge transport material can be identified by NMR, IR, mass spectrum or the like. The palladium content can be measured using an ICP emission spectrometer, and the purity can be calculated by a liquid chromatograph. The liquid chromatograph can be measured using an apparatus having a UV-vis detector.

≪Electrophotographic photoreceptor≫
The electrophotographic photoreceptor of the present invention will be described below.
The photosensitive layer of the electrophotographic photosensitive member is provided on the conductive support, and when it has an undercoat layer, it is provided on the undercoat layer. As the type of the photosensitive layer, the charge generation material and the charge transport material are present in the same layer and are dispersed in a binder resin, a so-called single-layer type photoreceptor, and charge generation in which the charge generation material is dispersed in a binder resin. A so-called laminated type photoreceptor having a multilayer structure in which a layer and a charge transport material are separated into two functions of a charge transport layer in which a binder resin is dispersed in a binder resin can be mentioned, but any structure may be used. Further, an overcoat layer may be provided on the photosensitive layer for the purpose of improving the chargeability and improving the wear resistance.

<Conductive support>
As the conductive support used for the photoreceptor, for example, metal materials such as aluminum, aluminum alloy, stainless steel, copper, nickel, and conductive powders such as metal, carbon, and tin oxide are added to impart conductivity. A resin material, a resin, glass, paper, or the like on which a conductive material such as aluminum, nickel, or ITO (indium tin oxide) is deposited or applied on the surface is mainly used. As a form, a drum shape, a sheet shape, a belt shape or the like is used. For conductive support of metallic materials, for control of conductivity, surface properties, etc. and for defect coating. A conductive material having an appropriate resistance value may be applied.

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, sealing treatment can be performed by a known method.
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.

<Underlayer>
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.

  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. 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 silicon. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. Moreover, the thing of the several crystal state may be contained.

  Various metal oxide particle diameters can be used. Among them, the average primary particle diameter is usually 1 nm or more, preferably 10 nm, from the viewpoint of electrical characteristics and the stability of the coating liquid for forming the undercoat layer. As described above, it is usually 100 nm or less, preferably 50 nm or less.

  The undercoat layer is preferably formed in a form in which metal oxide particles are dispersed in a binder resin. Examples of the binder resin used for the undercoat layer include epoxy resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, polyamide resin, vinyl chloride resin, vinyl chloride resin, vinyl acetate resin, phenol resin, polycarbonate resin, and polyurethane. Resin, polyimide resin, vinylidene chloride 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 ester resins such as nitrocellulose, cellulose ether resins, casein, gelatin, polyglutamic acid, starch, starch acetate, amino starch, zirconium Rate compounds, organic zirconium compounds such as zirconium alkoxide compounds, titanyl chelate compounds, organic titanyl compounds such as titanyl alkoxide compound, a known binder resin such as a silane coupling agent and the like. These may be used alone or in combination of two or more in any combination and ratio. Moreover, you may use with the hardening | curing form with the hardening | curing agent. Among these, alcohol-soluble copolymerized polyamides, modified polyamides, and the like are preferable because they exhibit good dispersibility and coatability.

The use ratio of the inorganic particles to the binder resin used in the undercoat layer can be arbitrarily selected, but is usually in the range of 10% by mass or more and 500% by mass or less from the viewpoint of the stability of the dispersion and coating properties. Is preferably used. The thickness of the undercoat layer can be selected arbitrarily, but is usually preferably in the range of 0.1 μm or more and 20 μm or less from the viewpoint of improving the photoreceptor characteristics and applicability.
A known antioxidant or the like may be mixed in the undercoat layer. For the purpose of preventing image defects, pigment particles, resin particles and the like may be contained and used.

<Photosensitive layer>
The photosensitive layer contains the charge transport material represented by the general formula (1), and the palladium content of the charge transport material is 0.01 to 150 ppm. Either a single layer type photosensitive layer or a multilayer type photosensitive layer may be used. As the multilayer type photosensitive layer, a layered type photosensitive layer in which a charge generation layer and a charge transport layer are laminated in this order from the conductive support side. Layer and a reverse laminated type photosensitive layer provided by laminating a charge transport layer and a charge generation layer in this order from the conductive support side, and any of them can be adopted, but a particularly well-balanced photoconductive layer A normally laminated photosensitive layer capable of exhibiting properties is preferred.

  The palladium content in the photosensitive layer is 50 ppm or less, preferably 45 ppm or less, more preferably 40 ppm or less from the viewpoint of electrical characteristics. From the viewpoint of reducing the purification load during production of the charge transport material and reducing the burden on the charge transport material during purification, it is 0.01 ppm or more, preferably 0.1 ppm or more, more preferably 0.5 ppm or more.

  The palladium content can be satisfied by forming a photosensitive layer using the charge transport material represented by the formula (1) obtained by combining the adsorbent, purification method and conditions used. The palladium content is quantitatively analyzed as follows using an ICP emission spectroscopic analyzer or an ICP mass spectrometer. First, the photosensitive layer is scraped off from the photoreceptor, and a certain amount is measured. Next, this is carbonized by a sample pretreatment apparatus, and various acids such as sulfuric acid and nitric acid are used alone or mixed and dissolved. The solution is ashed to remove organic matter, and the residue is further dissolved by using various acids such as sulfuric acid and nitric acid alone or by mixing them. This sample is quantitatively analyzed for palladium using an ICP emission spectroscopic analyzer or an ICP mass spectrometer.

In addition to the materials described below, the photosensitive layer has well-known antioxidants, plasticizers, and UV absorbers in order to improve film formability, flexibility, coatability, contamination resistance, gas resistance, light resistance, and the like. You may contain additives, such as an agent, an electron withdrawing compound, a leveling agent, and a visible light shading agent. 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.

<Charge generation layer>
The charge generation layer is formed by binding a charge generation material with a binder resin. Examples of the charge generation material include inorganic photoconductive materials such as selenium and its alloys, cadmium sulfide, and organic photoconductive materials such as organic pigments, but organic photoconductive materials are preferred, especially organic pigments. Is preferred. Examples of organic pigments include phthalocyanine pigments, azo pigments, dithioketopyrrolopyrrole pigments, squalene (squarylium) pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments. . Among these, phthalocyanine pigments or azo pigments are particularly preferable. When organic pigments are used as the charge generating substance, usually, fine particles of these organic pigments are used in the form of a dispersion layer bound with various binder resins.

  When a metal-free phthalocyanine compound or a metal-containing phthalocyanine compound is used as the charge generation material, a photosensitive member having a high sensitivity to a laser beam having a relatively long wavelength, for example, a laser beam having a wavelength around 780 nm, is obtained. When an azo pigment such as diazo or trisazo is used, it is sufficient for white light, laser light having a wavelength around 660 nm, or laser light having a relatively short wavelength, for example, laser having a wavelength around 450 nm or 400 nm. A photosensitive member having a high sensitivity can be obtained.

  When an organic pigment is used as the charge generating material, a phthalocyanine pigment or an azo pigment is particularly preferable. The phthalocyanine pigment provides a photosensitive material with high sensitivity to a laser beam having a relatively long wavelength, and the azo pigment has a sufficient sensitivity to white light and a laser beam having a relatively short wavelength. , Each is excellent.

  When using a phthalocyanine pigment as a charge generating material, specifically, metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, aluminum or other metal or oxide thereof, halide, water Those having crystal forms of coordinated phthalocyanines such as oxides and alkoxides, and phthalocyanine dimers using oxygen atoms as bridging atoms 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, hydroxyindium phthalocyanine, chlorogallium phthalocyanine such as type II, hydroxygallium phthalocyanine such as type V, μ-oxo-gallium phthalocyanine dimer such as type G and type I, type II, etc. The [mu] -oxo-aluminum phthalocyanine dimer is preferred.

  Among these phthalocyanines, A-type (also known as β-type), B-type (also known as α-type), and powder X-ray diffraction angle 2θ (± 0.2 °) are 27.1 ° or 27.3 °. D-type (Y-type) titanyl phthalocyanine, II-type chlorogallium phthalocyanine, V-type and 28.1 ° have the strongest peaks, and 26.2 ° have peaks A hydroxygallium phthalocyanine, G-type μ-oxo-gallium, having a clear peak at 28.1 ° and a half width W of 25.9 ° of 1 ° ≦ W ≦ 0.4 ° A phthalocyanine dimer and the like are particularly preferable.

The phthalocyanine compound may be a single compound or several mixed or mixed crystal states. As the mixed state that can be put in the phthalocyanine compound or crystal state here, those obtained by mixing the respective constituent elements later may be used, or they may be mixed in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. It may be the one that caused the condition. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are known. In order to generate a mixed crystal state, as described in JP-A-10-48859, two types of crystals are mixed, mechanically ground and made amorphous, and then converted into a specific crystal state by solvent treatment. The method of doing is mentioned.

  When an azo pigment is used as the charge generation material, various bisazo pigments and trisazo pigments are preferably used. When an organic pigment is used as the charge generation material, one kind may be used alone, or two or more kinds of pigments may be mixed and used. In this case, it is preferable to use a combination of two or more kinds of charge generating materials having spectral sensitivity characteristics in different spectral regions of the visible region and the near red region. Among them, a disazo pigment, a trisazo pigment and a phthalocyanine pigment are preferably used in combination. More preferred.

  The binder resin used for the charge generation layer is not particularly limited, but examples include polyvinyl butyral resin, polyvinyl formal resin, polyvinyl acetal type such as partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal, acetal, or the like. Resin, Polyarylate resin, Polycarbonate resin, Polyester resin, Modified ether type 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, cellulosic resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein, vinyl chloride -Vinyl acetate-vinyl acetate copolymers such as vinyl acetate copolymers, hydroxy-modified vinyl chloride-vinyl acetate copolymers, carboxyl-modified vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-maleic anhydride copolymers, etc. Insulating resins such as polymers, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, styrene-alkyd resins, silicon-alkyd resins, phenol-formaldehyde resins, poly-N-vinylcarbazole, polyvinyl anthracene, polyvinyl Examples include organic photoconductive polymers such as perylene. Any one of these binder resins may be used alone, or two or more thereof may be mixed and used in any combination.

Specifically, the charge generation layer is prepared by, for example, preparing a coating solution by dispersing a charge generation material in a solution obtained by dissolving the above-described binder resin in an organic solvent, and providing this on a conductive support (providing an undercoat layer). In some cases, it is formed by coating (on the undercoat layer).
In the charge generation layer, the mixing ratio (mass) of the binder resin and the charge generation material is usually 10 parts by mass or more, preferably 30 parts by mass or more, and usually 1000 parts by mass with respect to 100 parts by mass of the binder resin. Part or less, preferably 500 parts by weight or less.

The thickness of the charge generation layer is usually 0.1 μm or more, preferably 0.15 μm or more, and usually 10 μm or less, preferably 0.6 μm or less. If the ratio of the charge generation material is too high, the stability of the coating solution may be reduced due to aggregation of the charge generation material, while if the ratio of the charge generation material is too low, the sensitivity as a photoreceptor may be decreased. There is.
As a method for dispersing the charge generation material, a known dispersion method such as a ball mill dispersion method, an attritor dispersion method, a sand mill dispersion method, or a bead mill dispersion can be used. At this time, it is effective to refine the particles to a particle size in the range of 0.5 μm or less, preferably 0.3 μm or less, more preferably 0.15 μm or less.

<Charge transport layer>
The charge transport layer of the multilayer photoconductor contains a charge transport material, and usually a binder resin,
Contains other components used as necessary. 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, and in the case of a sequentially laminated photosensitive layer, the charge transport layer is formed on the charge generation layer. In the case of an inversely laminated photosensitive layer, it can be obtained by applying and drying on a conductive support (on the undercoat layer when an undercoat layer is provided).

  In the present invention, it is essential to use a charge transport material containing the compound represented by the formula (1), but other charge transport materials may be mixed and used. There is no particular limitation on the charge transporting material that may be used as a mixture, and any material can be used.

  Examples of other 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, 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 these compounds An electron donating substance such as a polymer in which a plurality of types are bonded, or a polymer having a group consisting of these compounds in the main chain or side chain is exemplified. 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.

  Specific examples of suitable structures of the charge transport material are shown below. 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. Any one of these charge transport materials may be used alone, or two or more thereof may be used in any combination.

  As the binder resin, vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, polycarbonate, polyester, polyester polycarbonate, polysulfone, phenoxy, epoxy, silicone resin, and other thermoplastic resins and various A thermosetting resin etc. are mentioned. Among these resins, polycarbonate resin or polyester resin is preferable.

  Specific examples of suitable structures of the binder resin are shown below. These specific examples are shown for illustration, and any known resin may be mixed and used as long as it is not contrary to the gist of the present invention.

  The viscosity average molecular weight of the binder resin is arbitrary as long as the effect of the present invention is not significantly impaired, but is usually 20,000 or more, preferably 40,000 or more, and usually 150,000 or less from the viewpoint of wear resistance. From the viewpoint of applicability, it is preferably 120,000 or less, more preferably 100,000 or less.

<Single layer type photosensitive layer>
The single-layer type photosensitive layer is formed using a charge generation material, a charge transport material represented by the formula (1), and a binder resin. Specifically, a charge generation material, a charge transport material, and various binder resins are dissolved or dispersed in a solvent to prepare a coating solution, and on a conductive support (on the undercoat layer when an undercoat layer is provided). It can be obtained by coating and drying.

  The charge transport material represented by the formula (1), the kind of the binder resin, and the use ratio thereof are the same as those in the charge transport layer of the multilayer photoreceptor. 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.

<Protective layer>
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 has a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 and JP-A-10-252377. The copolymer using the compound which has 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 and a skeleton having a charge transporting ability such as a triphenylamine skeleton as described in JP-A-9-190004 and JP-A-10-252377 can also be used. The protective layer is preferably configured to have an electric resistance of 10 ⁹ to 10 ¹⁴ Ω · cm.

  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 particles of inorganic compounds, such as a silica and an alumina, may be included.

<Method for forming photosensitive layer>
The photosensitive layer constituting the photosensitive member is formed by immersing, spraying, nozzle coating, bar coating, roll coating, blade coating a coating solution obtained by dissolving or dispersing a substance to be contained in an organic solvent. It is formed by repeating a coating / drying step sequentially for each layer by a known method such as coating.

  Examples of the organic solvent include aliphatic cyclic ethers such as tetrahydrofuran, methyltetrahydrofuran, tetrahydropyran, 1,4-dioxane, and 1,3-dioxolane, fats such as ethylpropyl ether, propyl ether, dibutyl ether, dimethoxyethane, and diethoxyethane. Ether-based solvents such as aromatic ethers such as aromatic chain ethers, anisole, methoxytoluene and phenetole, alcohols such as methanol, ethanol, propanol and 2-methoxyethanol, esters such as methyl formate and ethyl acetate, acetone, Ketones such as methyl ethyl ketone, cyclohexanone, 4-methoxy-4-methyl-2-pentanone, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, chloroform, 1,2-dichloroethane 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethane, 1,2-dichloropropane, trichlorethylene and other chlorinated hydrocarbons, n-butylamine, isopropanolamine, diethylamine, triethanolamine, Examples thereof include nitrogen-containing compounds such as ethylenediamine and triethylenediamine, and aprotic polar solvents such as acetonitrile, N-methylpyrrolidone, N, N-dimethylformamide and dimethylsulfoxide. Of these, aliphatic cyclic ethers, aromatic ethers, and aromatic hydrocarbons are preferable from the viewpoint of film-forming properties of the photosensitive layer, and tetrahydrofuran, 1,3-dioxolane, anisole, and toluene are preferable from the viewpoint of repeated transfer voltage resistance. More preferred.

Moreover, you may use 2 or more types together by arbitrary combinations and kinds. In the case of mixing, it is preferable to use an ether solvent and another solvent in combination from the viewpoint of repeated transfer voltage resistance, and aromatic hydrocarbons are preferable from the viewpoint of compatibility.
When used as a mixed solvent, the mass ratio [ether solvent / other solvent] is usually 1/2 or more, preferably 1/1 or more, more preferably 2/1 or more, from the viewpoint of repeated transfer voltage resistance. is there. From the viewpoint of applicability, it is usually 15/1 or less, preferably 10/1 or less.

It is preferable to adjust the coating solution for forming the photosensitive layer so that the mass ratio of the charge transport material to the solvent [charge transport material / solvent] is 1/10 to 1/100. From the viewpoint of solubility with the charge transport material, it is preferably 1/12 or less, and more preferably 1/15 or less. From the viewpoint of applicability, 1/90 or more is more preferable, and 1/50 or more is even more preferable.
When mixing the charge transport material and the solvent, it is preferable to dissolve by heating. From the viewpoint of solubility, the lower limit of the temperature of the solution during heating is usually 20 ° C. or higher, preferably 25 ° C. or higher, more preferably 30 ° C. or higher. From the viewpoint of preventing decomposition, the upper limit is usually 80 degrees or less, preferably 70 degrees or less, more preferably 65 degrees or less.

  For example, in the case of a charge transport layer of a single layer type photoreceptor or a function separation type photoreceptor, the solid content concentration of the coating solution is usually 5% by mass or more, preferably 10% by mass or more, and usually 40% by mass or less. The range is preferably 35% by mass or less. In addition, the viscosity of the coating solution is usually 10 mPa · s or higher, preferably 50 mPa · s or higher, and usually 1500 mPa · s or lower, preferably 1000 mPa · s or lower, at the temperature during use.

Above, preferably 1% by mass or more, usually 15% by mass or less, preferably 10% by mass or less. In addition, the viscosity of the coating solution is usually 0.01 mPa · s or higher, preferably 0.1 mPa · s or higher, and usually 20 mPa · s or lower, preferably 10 mPa · s or lower, at the temperature during use.
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, followed by heating or drying in a temperature range of usually 30 ° C. or more and 200 ° C. or less for 1 minute to 2 hours, while still or blowing. Further, the heating temperature may be constant, or heating may be performed while changing the temperature during drying.

<Cartridge, image forming apparatus>
Next, a drum cartridge and an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described with reference to FIG.

  In FIG. 1, reference numeral 1 denotes a drum-shaped photoconductor, which is rotationally driven at a predetermined peripheral speed in the direction of an arrow. The photosensitive member 1 is uniformly charged at a predetermined positive or negative potential on the surface by the charging unit 2 during the rotation process, and then exposure for forming a latent image is performed by the image exposure unit in the exposure unit 3.

The formed electrostatic latent image is then developed with toner by the developing means 4, and the toner developed image is sequentially transferred onto the transfer body (paper or the like) P fed from the paper feeding unit by the corona transfer means 5. . In FIG. 1, the developing unit 4 includes a developing tank 41, an agitator 42, a supply roller 43, a developing roller 44, and a regulating member 45. The developing unit 4 stores toner T inside the developing tank 41. . Further, a replenishing device (not shown) for replenishing the toner T may be attached to the developing unit 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 image-transferred transfer body is then sent to the fixing means 7 where the image is fixed and printed out of the apparatus. The fixing unit 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. Each of the upper and lower fixing members 71 and 72 includes a fixing roll in which a metal base tube such as stainless steel or aluminum is coated with silicon rubber, a fixing roll in which Teflon (registered trademark) resin is coated, a fixing sheet, or the like. A member can be used. Further, each of the fixing members 71 and 72 may be configured to supply a release agent such as silicone oil in order to improve 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 surface of the photoreceptor 1 after the image transfer is cleaned by the cleaning unit 6 to remove the transfer residual toner, and is neutralized by the neutralization unit for the next image formation.

  In using the electrophotographic photosensitive member of the present invention, as a charger, in addition to a corona charger such as corotron or scorotron, a direct charging means for charging a charged member by contacting a directly charged member to which voltage is applied is provided. It may be used. Examples of the direct charging means include a contact charger such as a charging roller and a charging brush. As the direct charging means, any one that involves air discharge or injection charging that does not involve air discharge is possible. Moreover, as a voltage applied at the time of charging, it is possible to use only a direct current voltage or to superimpose an alternating current on a direct current.

  For the exposure, a halogen lamp, a fluorescent lamp, a laser (semiconductor, He—Ne), LED, a photoreceptor internal exposure system, or the like is used. As a digital electrophotographic system, it is preferable to use a laser, an LED, an optical shutter array, or the like. . As the wavelength, in addition to 780 nm monochromatic light, it is possible to use monochromatic light in the 600 to 700 nm region and slightly shorter wavelength.

For the development process, a dry development method such as cascade development, one-component insulating toner development, one-component conductive toner development, two-component magnetic brush development, or the like is used.
As the toner, in addition to the pulverized toner, chemical toners such as suspension granulation, suspension polymerization, and emulsion polymerization aggregation can be used. In particular, in the case of chemical toners, those having a small particle diameter of about 4 to 8 μm are used, and those having a shape close to a sphere, and those outside a potato-like sphere can also be used. The polymerized toner is excellent in charging uniformity and transferability, and is preferably used for high image quality.

  For the transfer process, electrostatic transfer methods such as corona transfer, roller transfer, and belt transfer, pressure transfer methods, and adhesive transfer methods are used. For fixing, heat roller fixing, flash fixing, oven fixing, pressure fixing, IH fixing, belt fixing, IHF fixing, etc. are used. These fixing methods may be used alone or in combination with a plurality of fixing methods. May be.

For cleaning, brush cleaner, magnetic brush cleaner, electrostatic brush cleaner, magnetic roller cleaner, blade cleaner, etc. are used.
In many cases, the static elimination step is omitted, but when used, a fluorescent lamp, LED, or the like is used, and an exposure energy that is three times or more of the exposure light is often used as the intensity. In addition to these processes, a pre-exposure process and an auxiliary charging process may be included.

  In the present invention, a plurality of components such as the drum-shaped photosensitive member 1, the charging unit 2, the developing unit 4 and the cleaning unit 6 are integrally combined as a drum cartridge, and the drum cartridge is copied. It may be configured to be detachable from the main body of an electrophotographic apparatus such as a machine or a laser beam printer. For example, at least one of the charging unit 2, the developing unit 4, and the cleaning unit 6 can be integrally supported together with the drum-shaped photoreceptor 1 to form a cartridge.

A color image can be obtained by adjusting magenta, yellow, cyan, and black toners in multiple layers to a desired color. In the case of the tandem system, the color development part located before the black development part may reduce color mixing due to reverse transfer of black toner, and the black development part located behind the color development part is only black. In the case of forming an image with a single color, it is preferable that the color mixture due to the photosensitive member fog of the color toner is reduced, and the speed of black image formation can be increased by transporting the recording paper by short-passing the color developing unit. .

  When applied to full-color image formation, such a cyan, magenta, and yellow color development unit is suitable for a tandem system in which the black development unit is located after the color development unit. It should be noted that the order in which the cyan, magenta, and yellow color developing units are positioned can be freely changed in a timely manner.

  Hereinafter, the embodiment of the present invention will be described more specifically with reference to examples. However, the following examples are given in order to explain the present invention in detail, and the present invention is not limited to the examples shown below without departing from the gist thereof, and can be arbitrarily modified and implemented. can do. In addition, the description of “parts” in the following examples and comparative examples indicates “parts by mass” unless otherwise specified.

<Production of Charge Transport Material Represented by Formula (1)>
(Production Example 1: CT1 crude body)
A charge transport material having a structural formula represented by the following formula (CT1) was produced according to Scheme A below. Detailed conditions are as follows.

In 500 ml of xylene, 23.5 g of compound A which is a triphenylamine derivative, 2.7 g of p-toluidine, 10.6 g of sodium t-butoxide, 500 m of palladium acetate
g, 20 ml of a 0.6 mmol / ml toluene solution of tricyclohexylphosphine was charged, and the temperature was raised until reflux occurred. After the temperature rise, the mixture was stirred for 3 hours to react, and after the reaction was completed, the reaction solution was cooled to room temperature, 250 ml of water was added, and the mixture was stirred for 30 minutes. After stirring, the aqueous layer is separated, the organic layer is washed with deionized water, concentrated, and the concentrated residue is dissolved in tetrahydrofuran to prepare a tetrahydrofuran solution of the crude CT1. The solution is added to methanol and stirred. Thereafter, 18.4 g of a charge transport material CT1 crude product was obtained by filtration and drying. (Yield 85.4%)

(Production Example 2)
A toluene solution of the CT1 crude material was prepared by dissolving 10 g of the charge transport material CT1 crude product obtained in Production Example 1 in 100 g of toluene. In this toluene solution, 5 g of activated clay was added, stirred and filtered. The purified solution after repeating this purification with activated clay [adsorbent treatment-filtration] three times is concentrated, and the concentrated residue is dissolved in tetrahydrofuran. The solution is added to methanol, solidified by reprecipitation, and stirred. By filtration and drying, 9.3 g of a charge transport material CT1 was obtained. It was 83 ppm when palladium content in obtained CT1 was confirmed by the ICP emission analysis.

(Production Example 3)
The same operation as in Production Example 2 was performed except that 5 g of activated clay used for the second treatment when the purification [Adsorbent Treatment-Filtration] in Production Example 2 was repeated three times was changed to 2.0 g of Florisil. As a result, 9.4 g of a charge transport material CT1 was obtained. It was 41 ppm when the palladium content in obtained CT1 was confirmed by the ICP emission analysis.

(Production Example 4)
The same operation as in Production Example 2 was performed except that 5 g of activated clay used for the second treatment in the case of repeating purification [adsorbent treatment-filtration] three times in Production Example 2 was changed to 1.5 g of activated carbon. As a result, 9.3 g of charge transport material CT1 was obtained. It was 117 ppm when the palladium content in obtained CT1 was confirmed by the ICP emission analysis.

(Production Example 5)
The same operation as in Production Example 2 was performed except that 5 g of activated clay used in the second treatment when the purification [Adsorbent treatment-filtration] in Production Example 2 was repeated three times was changed to 2.0 g of silica gel. As a result, 9.3 g of a charge transport material CT1 was obtained. The palladium content in the obtained CT1 was confirmed to be 112 ppm by ICP emission analysis.

(Production Example 6)
A charge transport material having a structural formula represented by the following formula (CT2) was produced according to the following scheme B. Detailed conditions are as follows.

In 500 ml of xylene, 18.8 g of compound A which is a triphenylamine derivative, 2.8 g of p-phenetidine, 8.5 g of sodium t-butoxide, 100 m of palladium acetate.
g, 16 ml of a 0.6 mmol / ml toluene solution of tricyclohexylphosphine was charged, and the temperature was raised until reflux occurred. After heating, the mixture was stirred for 3 hours to be reacted. After completion of the reaction, the reaction solution was cooled to room temperature, 200 ml of water was added, and the mixture was stirred for 30 minutes. After stirring, the aqueous layer is separated, the organic layer is washed with deionized water, concentrated, and the concentrated residue is dissolved in tetrahydrofuran to prepare a tetrahydrofuran solution of CT2 crude, and the solution is added to methanol and stirred. Then, 13.7g of charge transport material CT2 crude bodies were obtained by filtering and drying. (Yield 75.8%)
9.1 g of charge transport material CT2 was obtained by operating 10 g of the obtained charge transport material CT2 crude product in the same manner as in Production Example 2. The palladium content in the obtained CT2 was confirmed to be 14 ppm by ICP emission analysis.

(Comparative Production Example 1)
10 g of the charge transport material CT1 crude product obtained in Production Example 1 was heated in 40 g of toluene and completely dissolved, and then cooled to 0 ° C. or lower. 6.3g of charge transport material CT1 was obtained by standing still in a cooling state, crystallizing, and filtering and drying. It was 180 ppm when palladium content in obtained CT1 was confirmed by the ICP emission analysis.

(Comparative Production Example 2)
A charge transport material having a structural formula represented by the following formula (CT1) was produced according to the following scheme C. Detailed conditions are as follows.

In 300 ml of tetrahydrofuran, 26.7 g of compound B which is a triphenylamine derivative and 9.5 g of compound C were charged and dissolved. After dissolution, potassium t-butoxide 7.5
g was added and stirred at room temperature for 2 hours. After completion of the reaction, the reaction solution was added to 1000 ml of methanol and stirred for 30 minutes. After stirring, 17.5 g of a charge transport material CT1 crude product was obtained by filtration and drying (yield: 68.3%).
8.3 g of charge transport material CT1 was obtained by operating 10 g of the obtained charge transport material CT1 crude product in the same manner as in Production Example 2. When the palladium content in the obtained CT1 was confirmed by ICP emission analysis, palladium was not detected.

<Manufacture of coating liquid for undercoat layer formation>
A rutile type titanium oxide having an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% by mass of methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide were added to a Henschel mixer. 1 kg of a raw slurry obtained by mixing 50 parts of surface-treated titanium oxide obtained by mixing with 120 parts of methanol, and using a zirconia bead having a diameter of about 100 μm (YTZ manufactured by Nikkato Co., Ltd.) as a dispersion medium, a mill volume of about 0 Using a 15-liter Ultra Apex Mill (UAM-015 type) manufactured by Kotobuki Kogyo Co., Ltd., a titanium oxide dispersion was prepared by dispersing for 1 hour in a liquid circulation state with a rotor peripheral speed of 10 m / second and a liquid flow rate of 10 kg / hour. .

The titanium oxide dispersion, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula Compound represented by (B)] / hexamethylenediamine [compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [following formula (E ) And a copolymerized polyamide pellet having a composition molar ratio of 75% / 9.5% / 3% / 9.5% / 3% while stirring and mixing the mixture to obtain polyamide pellets. After dissolution, ultrasonic dispersion with an ultrasonic transmitter with an output of 1200 W is performed for 1 hour, and a PTFE membrane filter (a) with a pore size of 5 μm is added. The mixture was filtered through Dovetec Mytecs LC), and the mass ratio of the surface-treated titanium oxide / copolymerized polyamide was 3/1, and the mass ratio of the mixed solvent of methanol / 1-propanol / toluene was 7/1/2. Thus, a coating solution for forming an undercoat layer having a solid content concentration of 18.0% by mass was prepared.

<Manufacture of coating solution for forming charge generation layer>
As a charge generation material, 20 parts of oxytitanium phthalocyanine and 280 parts of 1,2-dimethoxyethane showing the X-ray diffraction spectrum by CuKα characteristic X-ray in FIG. 2 are mixed, and pulverized and dispersed in a sand grind mill for 1 hour. Processing was performed. 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 binder solution obtained by dissolving in a mixed solution of 85 parts of -2-pentanone and 230 parts of 1,2-dimethoxyethane were mixed to prepare a coating solution A for forming a charge generation layer.

  As a charge generation material, 20 parts of oxytitanium phthalocyanine showing X-ray diffraction spectrum by CuKα characteristic X-ray in FIG. 3 and 280 parts of 1,2-dimethoxyethane are mixed and pulverized in a sand grind mill for 4 hours to be atomized and dispersed. Processing was performed. 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 binder solution obtained by dissolving in a mixed solution of 85 parts of -2-pentanone and 230 parts of 1,2-dimethoxyethane were mixed to prepare a coating solution B for forming a charge generation layer. The charge generation layer forming coating solution A and the charge generation layer forming coating solution B were mixed at a mass ratio of 8: 2 to prepare a charge generation layer forming coating solution used in this example.

<Manufacture of coating liquid for charge transport layer formation>
[Coating liquid C1]
100 parts of a polyarylate resin represented by the following repeating structure (resin X, viscosity average molecular weight 70,000), 40 parts of the charge transport material prepared in Production Example 2, 4 parts of compound AD1 represented by the following formula, Charge transport layer by dissolving 1 part of AD2, 1 part of AD3, 0.03 part of dimethylpolysiloxane (KF96-10CS manufactured by Shin-Etsu Chemical Co., Ltd.) in 880 parts of tetrahydrofuran / toluene (8/2 (mass ratio)) mixed solvent A forming coating solution C1 was prepared.

[Coating fluid C2-5]
Coating solutions C2 to C5 were prepared in the same manner as the coating solution C1, except that the charge transporting material prepared in Production Examples 3 to 6 was used instead of the charge transporting material of Production Example 2 as the charge transporting material.

[Coating fluid C6-7]
Coating solutions C6-7 were prepared in the same manner as the coating solution C1, except that the charge transporting material prepared in Comparative Production Examples 1-2 was used instead of the charge transporting material of Production Example 2 as the charge transporting material. .

<Manufacture of photosensitive drum>
The coating solution for forming the undercoat layer and the coating solution for forming the charge generation layer prepared in the manufacturing example of the coating solution on a cylinder made of an aluminum alloy having an outer diameter of 60 mm, a length of 248 mm, and a wall thickness of 1.0 mm. The coating solution for forming the charge transport layer is sequentially applied and dried by the dip coating method, and the undercoat layer, the charge generation layer, the charge are formed so that the dried film thicknesses are 1.5 μm, 0.5 μm, and 21 μm, respectively. A transport layer was formed to produce a photoreceptor drum. The charge transport layer is dried by 12
Performed at 5 ° C. for 24 minutes. Further, the photosensitive layer was peeled from the obtained photoreceptor, and ICP emission analysis [apparatus: ICPS-8100S manufactured by Shimadzu Corporation] was performed to measure the palladium content in the photosensitive layer.

<Image test>
The obtained photoreceptor is mounted on a photoreceptor cartridge of a Samsung 4-cycle full-color printer CLP-320 (DC roller charging, LD exposure, non-magnetic one-component jumping development), and the temperature is 35 ° C. and the relative humidity is 85% lower. , Continuous printing of 6000 sheets was performed at a printing rate of 5%. After printing 6000 sheets, a halftone image was printed, and the white spot of the image was determined as follows.

White evaluation criteria A: No white spots are seen in halftone images. ○: White spots are not seen in some halftone images. Δ: Mild white spots are seen in the whole halftone images. The image has clear white spots throughout

<Evaluation of electrophotographic photoreceptor>
The electrophotographic photoreceptors of Examples 1 to 5 and Comparative Examples 1 to 2 described in Table 1 were produced in accordance with electrophotographic characteristics standards ("Basic and Application of Secondary Electrophotographic Technology", Electron The electrical characteristics were evaluated by carrying out a cycle of charging, exposure, potential measurement, and static elimination according to the following procedure.

  After charging so that the initial surface potential of the photoconductor becomes −700 V under the conditions of a temperature of 25 ° C. and a humidity of 50%, the light of the halogen lamp is converted to monochromatic light of 780 nm with an interference filter and irradiated with 0.6 μJ / cm 2. The surface potential (unit: -V) measured after exposure with energy was defined as the residual potential.

[Examples 1-5, Comparative Examples 1-2]
Table 1 shows the results of producing and evaluating the photosensitive drum shown in Table-1.

  As can be seen from Table 1, when the electrophotographic photosensitive member of the present invention is used, the residual potential after exposure is low, and when continuous printing is performed at high temperature and high humidity, white spots do not occur and good results are obtained. It was.

1 Photoconductor (Electrophotographic photoconductor)
2 Charging device (charging roller; charging unit)
3 Exposure equipment (exposure section)
4 Development device (development unit)
DESCRIPTION OF SYMBOLS 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 (fixing roller)
72 Lower fixing member (fixing roller)
73 Heating device T Toner P Recording paper (paper, medium)

Claims (10)

An electrophotographic photosensitive member having a photosensitive layer containing a charge transport material on a conductive support, wherein the charge transport material contains a compound represented by the general formula (1) and palladium, and palladium in the charge transport material An electrophotographic photoreceptor having a content of 0.1 to 120 ppm.

(In the formula ^(1), Ar 1 ~Ar ⁵ is to display the independent aryl group. However, the ants
The alkyl group is selected from the group consisting of an alkyl group, an alkoxy group, an aryl group, and a halogen atom.
It may be substituted with at least one selected from the above. Ar ^{6 to} Ar ⁹ each independently represents a 1,4-phenylene group which may have a substituent. m and n each independently represent an integer of 1 to 3. ) The photosensitive layer is a photosensitive layer laminated in the order of a charge generation layer and a charge transport layer from the conductive support side, and the compound represented by the formula (1) contained in the charge transport layer is a charge layer. The electrophotographic photosensitive member according to claim 1, wherein the electrophotographic photosensitive member is 20 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the binder resin forming the transport layer. In the formula (1), Ar ^{1 to} Ar ⁵ each represents an independent aryl group (provided that the above
The aryl group may be substituted with an alkyl group or an alkoxy group. ) , Ar ⁶ -A
r ⁹ is independently a 1,4-phenylene group which may have a substituent, and m and n are 1
The electrophotographic photosensitive member according to claim 1 or 2, characterized in that. The electrophotographic photosensitive member according to any one of claims 1 to 3 , wherein the photosensitive layer contains a binder resin, and the binder resin is a polyarylate resin or a polycarbonate resin. Characterized in that it is used in a full-color image forming apparatus, an electrophotographic photosensitive member according to any one of claims 1-4. The electrophotographic photosensitive member according to any one of claims 1 to 5, and a charging device for charging the electrophotographic photosensitive member, a charging and exposure apparatus which forms a by exposing the electrophotographic photoreceptor electrostatic latent image And an at least one member selected from the group consisting of developing devices for developing an electrostatic latent image formed on the electrophotographic photosensitive member. The electrophotographic photosensitive member according to any one of claims 1 to 5 charging device for charging the electrophotographic photoreceptor, an exposure device and the charged electrophotographic photosensitive member is exposed to form an electrostatic latent image A full-color image forming apparatus comprising a developing device for developing an electrostatic latent image formed on an electrophotographic photosensitive member. A charge transport material comprising a compound represented by the general formula (1) and palladium, wherein the charge transport material has a palladium content of 0.1 to 120 ppm.

(In the formula ^(1), Ar 1 ~Ar ⁵ is to display the independent aryl group. However, the ants
The alkyl group is selected from the group consisting of an alkyl group, an alkoxy group, an aryl group, and a halogen atom.
It may be substituted with at least one selected from the above. Ar ^{6 to} Ar ⁹ each independently represents a 1,4-phenylene group which may have a substituent. m and n each independently represent an integer of 1 to 3. ) In the method for producing an electrophotographic photosensitive member having a photosensitive layer containing a charge transporting material represented by the general formula (1) on a conductive support, the palladium content is 0.1 after synthesis using a palladium compound. A method for producing an electrophotographic photosensitive member, comprising forming a photosensitive layer using an organic solvent containing the charge transporting substance purified to ˜120 ppm and a binder resin.

(In the formula (1), ^Ar 1 ~Ar ⁵ is to display the independent aryl group. However, the ants
The alkyl group is selected from the group consisting of an alkyl group, an alkoxy group, an aryl group, and a halogen atom.
It may be substituted with at least one selected from the above. Ar ^{6 to} Ar ⁹ each independently represents a 1,4-phenylene group which may have a substituent. m and n each independently represent an integer of 1 to 3. ) The method for producing an electrophotographic photosensitive member according to claim 9 , wherein the compound represented by the formula (1) is purified using an adsorbent.

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