JP5652608B2 - Electrophotographic photosensitive member, image forming apparatus, and process cartridge for image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a laser printer, and a facsimile, a process cartridge, and an electrophotographic photosensitive member used for them. Specifically, the present invention relates to an electrophotographic photoreceptor excellent in image quality stability and durability, a process cartridge for an image forming apparatus using the same, and an image forming apparatus.

  In recent years, organic photoreceptors have been widely used for electrophotographic photoreceptors (hereinafter also simply referred to as photoreceptors). For organic photoreceptors, it is easy to develop materials compatible with various exposure light sources from visible light to infrared light, to select materials that are less affected by environmental pollution, and to reduce manufacturing costs. There are many advantages. Disadvantages over inorganic photoreceptors include poor mechanical durability. From the viewpoint of effective use of resources, it is preferable that the mechanical durability is sufficient and the life is long.

-Mechanical durability Generally, an electrophotographic image forming apparatus is an electrophotographic photosensitive member, a charger for charging the electrophotographic photosensitive member, and an electrostatic latent image on the surface of the electrophotographic photosensitive member charged by the charger. A latent image forming device that forms an image, a developing device that attaches toner to an electrostatic latent image formed by the latent image forming device, a transfer means that transfers the attached toner to a transfer object, and a photosensitive member that is not transferred. A cleaning device or the like for removing toner remaining on the body surface is integrally provided.
In the organic photoreceptor, the surface of the photoreceptor is chemically or physically deteriorated by repeating the steps such as charging, development, transfer, and cleaning as described above, and wear is promoted or scratches are formed. As a result, the image quality deteriorates at an early stage, and the mechanical durability of the organic photoreceptor has been regarded as one of the most important issues. On the other hand, many techniques for providing a protective layer for the purpose of improving the mechanical durability of the organic photoreceptor are disclosed.

  For example, many techniques for improving mechanical durability by providing a protective layer on the outermost surface of the photoreceptor and dispersing inorganic fine particles in the protective layer have been disclosed. As an example, Patent Document 1 proposes an electrophotographic photosensitive member in which at least a photosensitive layer and a protective layer containing a filler are sequentially formed on a conductive support. As another means, many techniques for improving by increasing the hardness of the photoreceptor surface have been disclosed. For example, in Patent Document 2 and Patent Document 3, when a magnetic brush type is applied as a charger, magnetic particles are involuntarily transferred onto the photoconductor, and the particles are transferred to the photoconductor in the transfer unit or the cleaning unit. It has been proposed to increase the hardness of the photoconductor protective layer in order to prevent scratching due to strong pressing. Further, Patent Document 4 proposes to increase the hardness of the photoconductor in order to suppress photoconductor surface wear when the blade-type cleaning method is applied. As specific means for increasing the surface hardness of the photoreceptor as described above, it has been proposed to use a crosslinkable material such as a thermosetting resin or a UV curable resin as a constituent component of the photoreceptor protective layer. For example, Patent Documents 5 to 7 propose methods for improving the mechanical durability and scratch resistance of the protective layer by applying a thermosetting resin as a binder component of the protective layer. Further, Patent Documents 8 to 10 disclose a technique for improving mechanical durability and scratch resistance by including a protective layer with a siloxane resin bonded with a charge transporting ability-imparting group. Further, in Patent Document 11, in order to improve mechanical durability and scratch resistance, the charge transport layer is made of a monomer having a carbon-carbon double bond, a charge transport material having a carbon-carbon double bond, and a binder resin. The method of making is reported. Patent Document 12 describes a method for forming a charge transport layer by curing a tri- or higher functional radical polymerizable monomer having no charge transport structure and a radical polymerizable compound having a monofunctional charge transport structure. Has been. Further, Patent Document 13 discloses a method of forming a protective layer in which a tri- or higher functional radical polymerizable monomer having no charge transporting structure and a radical polymerizable compound having a charge transporting structure are further cured and a filler is dispersed. Is described. By using the above means, the mechanical durability of the photoreceptor is dramatically improved. In particular, a photoreceptor using a curable resin described in Patent Document 12 or Patent Document 13 as a protective layer is excellent in mechanical durability and scratch resistance.

However, it is difficult to achieve a long life only by increasing the mechanical durability. In order to extend the life of the photoreceptor, it is essential to prevent foreign matter adhesion and improve the toner transfer rate.
Even if the photoconductor is excellent in mechanical durability, an abnormal image may occur when it is used for a long time. The adhesion of paper dust and toner additives can cause this. The portion to which these are attached is not correctly charged or exposed, and an abnormal image may occur. If the photoconductor is inferior in mechanical durability, the outermost surface is worn, so that the occurrence of abnormal images can be suppressed, but it is difficult to achieve a long life.
If the toner transfer rate is increased, useless toner can be avoided. If there is a large amount of toner remaining after transfer, a burden is placed on the cleaning unit. As a result, the cleaning effect is not sustained, and the life of the process cartridge is shortened. Thus, it is very important to increase the toner transfer rate.

  Since prevention of foreign matter adhesion and improvement in toner transfer rate often exhibit similar properties, both are expressed as releasability. Lowering the energy of the outermost surface is effective for improving mechanical durability and imparting releasability. There are two methods for reducing the surface energy of a photoreceptor: an external addition system for applying a low surface energy reducing material and an internal addition system for containing a low surface energy reducing material in the film. As an external additive system, a mechanism for applying zinc stearate or the like to the surface of a photoreceptor is generally known. With this mechanism, it is possible to impart releasability to the surface of the photoreceptor. However, the surface energy reducing material on the surface may be deteriorated by the discharge and cause an abnormal image. Further, by providing the coating mechanism, the image forming portion becomes large, and the degree of freedom in layout decreases. Furthermore, the cost of the image forming unit increases. An internal addition system containing a low surface energy reducing material in the film is also effective for improving the releasability. However, in order to always deposit the low surface energy reducing material on the surface, it is necessary to always wear the surface of the photoreceptor. Therefore, mechanical durability is sacrificed.

This paper describes the compatibility between mechanical durability and releasability. In order to impart high releasability to the surface of the photoreceptor, Patent Document 14 describes a photoreceptor using a polysiloxane resin substituted with fluorine in the surface layer. However, siloxane bonds are known to cause polarization and hydrogen bonding. For this reason, the adhesion force with the toner may be increased under high humidity. Thereby, the releasability may be lowered under high humidity.
Patent Document 15 describes a photoreceptor in which lubricating fine particles are contained in a protective layer. Patent Document 16 describes a photoreceptor having a surface protective layer made of a cured product of a fluorine-containing photocurable composition containing a fluorinated alkyl group-containing (meth) acrylate and a photopolymerization initiator. . Patent Document 17 discloses that a crosslinkable surface layer is cured with a fluorine-based UV curable hard coat agent and a radical polymerizable compound having a monofunctional charge transporting structure, and further has a protective layer containing lubricating fine particles. A photoreceptor is described. Use of a fluorine-based material is an effective means for reducing the adhesion between the photoreceptor and the toner. In particular, when it is contained in the crosslinkable charge transport layer, it is possible to achieve both high mechanical durability and reduced adhesion between the photoreceptor and the toner. However, in order to sufficiently reduce the adhesive force, it is necessary to contain a considerable amount of fluorine material. Since these fluorine-based materials do not have a charge transporting property, when added in a large amount, the bright part potential may increase. Furthermore, the film strength tends to decrease.

Patent Document 18 describes a photoreceptor having a surface layer composed of a compound having an aliphatic carbocyclic structure having 7 or more carbon atoms and a polymerizable functional group, a binder resin, and a charge transport material. In this case, since the resin and the binder resin are not crosslinked, the mechanical strength of the film is low. Therefore, it is not suitable for extending the life of the photoreceptor. In Patent Documents 19 and 20, there is a description of a photoreceptor having a cross-linked charge transport layer prepared from a copolymer of a radical polymerizable monomer and a radical polymerizable charge transport material. In the case of this configuration, the wear resistance is improved. However, since it is greatly inferior in the part of releasability, foreign matter adhesion is likely to occur, and it is difficult to achieve a long life.
As described so far, it is difficult to achieve both mechanical durability and high releasability, and an electrophotographic photosensitive member specialized for one of the characteristics must be designed.

  The present invention provides an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge for an image forming apparatus that can achieve both mechanical durability and high releasability and can stably output high image quality even when used repeatedly over a long period of time. The issue is to provide.

The above problems are solved by the following (1) to ( 7 ).
(1) In an electrophotographic photosensitive member in which at least a charge generation layer, a charge transport layer, and a cross-linked charge transport layer are sequentially laminated on a conductive support,
An electrophotographic photoreceptor, wherein the cross-linked charge transport layer comprises structural units derived from the following first component, second component and third component.
First component: a copolymer comprising two or more repeating units, wherein at least one repeating unit of the two or more repeating units contains at least one cyclic structure selected from an adamantane ring and a norbornane ring Second component: radical polymerizable monomer having no charge transport structure and / or radical polymerizable oligomer having no charge transport structure Third component: at least one kind of radical polymerizable compounds having a charge transport structure ( 2 ) The electrophotographic photosensitive member according to (1), wherein the copolymerization ratio of the cyclic compound of the copolymer of the first component is 0.3 or more and 0.9 or less in terms of molar ratio.

( 3 ) The electrophotographic photosensitive member as described in (1) or (2) , wherein the charge transporting layer contains at least one distyrylbenzene derivative represented by the following general formula (1) as a charge transporting substance: body.
[In the above formula, R _{1 to} R ₃₀ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. A substituted aryl group, an unsubstituted aryl group, an alkyl group having 1 to 4 carbon atoms or a benzyl group substituted with an alkoxy group having 1 to 4 carbon atoms may be the same or different. ]
( 4 ) The electrophotographic photosensitive member according to any one of (1) to ( 3 ), wherein the crosslinkable charge transport layer contains at least one filler fine particle.

( 5 ) In an image forming apparatus comprising at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member, the electrophotographic photosensitive member according to any one of (1) to ( 4 ) An image forming apparatus comprising the electrophotographic photosensitive member described above.
( 6 ) A plurality of image forming elements comprising at least charging means, exposure means, developing means, and electrophotographic photosensitive member are arranged, and the electrophotographic photosensitive member is an electron according to any one of (1) to ( 4 ) An image forming apparatus characterized by being a photographic photoreceptor.
( 7 ) In the process cartridge for an image forming apparatus, in which the electrophotographic photosensitive member and at least one means selected from a charging means, an exposure means, a developing means, a transfer means, and a cleaning means are combined, the electrophotographic photosensitive member A process cartridge for an image forming apparatus, wherein the electrophotographic photosensitive member according to any one of (1) to ( 4 ).

  The electrophotographic photosensitive member of the present invention is excellent in abrasion resistance and scratch resistance by providing a cross-linked charge transport layer on the surface, can reduce adhesion of foreign matters, and has a high toner transfer rate. Therefore, it is possible to provide an electrophotographic photosensitive member, an image forming apparatus, and a process cartridge for an image forming apparatus that can stably output high image quality even when used repeatedly for a long time.

It is sectional drawing which shows the structural example of the electrophotographic photoreceptor in this invention. 1 is a schematic diagram illustrating an example of an image forming apparatus according to the present invention. It is a figure which shows an example of the process cartridge in this invention. 1 is a schematic diagram illustrating an example of an apparatus in which a plurality of image forming elements are arranged in the present invention. It is an X-ray diffraction spectrum diagram of the charge generation material used in the examples, the vertical axis represents the counts per second (cps: counts per second), and the horizontal axis represents the angle (2θ). 3 is an SPM image of the electrophotographic photosensitive member used in the present invention. The scan size on the horizontal axis is 10 μm scale, and the data scale on the vertical axis is 50 nm. 3 is an SPM image of the electrophotographic photosensitive member used in the present invention. The scan size on the horizontal axis is 10 μm scale, and the data scale on the vertical axis is 50 nm.

  In the present invention, the reason why both high mechanical durability and high releasability can be considered will be considered. The crosslinkable charge transport layer of the present invention comprises a first component, a monomer or an oligomer which is a copolymer comprising two or more repeating units, and at least one repeating unit containing at least one cyclic structure. A second component that is a radically polymerizable compound that does not have one or more kinds of charge transporting structures selected, and a structural unit derived from a third component that is a radically polymerizable compound that has at least one kind of charge transporting structures . Of these, the copolymer of the first component is less soluble than the other components. Therefore, it is considered that the copolymer component precipitates on the film surface during drying or light irradiation, and has a fine sea-island structure. This sea-island structure is considered to have provided release properties to the film surface. Further, since the film is cross-linked, it is considered that the mechanical durability is excellent. This is a structure fundamentally different from that of JP-A-2003-302779 (Patent Document 18) in which the film is not crosslinked and inferior in mechanical durability, and the effect is also excellent. Further, unlike JP-A-5-216249 (Patent Document 19) and JP-A-2005-55589 (Patent Document 20), the release property is remarkably increased by having a cyclic structure in the copolymer. It was.

The image forming apparatus of the present invention will be described in detail below with reference to the drawings.
<< Configuration of electrophotographic photoreceptor >>
As shown in FIG. 1, the photoreceptor of this embodiment has at least a charge generation layer 32, a charge transport layer 33, and a crosslinked charge transport layer 34 in this order on a conductive support 31. It is a type.

<About conductive support>
Examples of the conductive support include those having a volume resistance of 10 ¹⁰ Ω · cm or less, such as metals such as aluminum, nickel, chromium, nichrome, copper, gold, silver, and platinum, tin oxide, and indium oxide. After metal oxide is deposited or sputtered, film or cylindrical plastic, paper coated, or aluminum, aluminum alloy, nickel, stainless steel, etc. Pipes that have been subjected to surface treatment such as cutting, super-finishing, and polishing can be used. Further, endless nickel belts and endless stainless steel belts disclosed in JP-A-52-36016 can also be used as the conductive support.
In addition, the conductive support dispersed in an appropriate binder resin on the support can be used as the conductive support of the present invention. Examples of the conductive powder include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc and silver, or metal oxide powder such as conductive tin oxide and ITO. Can be mentioned.

The binder resin used at the same time includes polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, Polyvinyl acetate, polyvinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinylcarbazole, acrylic resin, silicone resin, epoxy resin, melamine Examples thereof include thermoplastic resins such as resins, urethane resins, phenol resins, and alkyd resins, thermally crosslinkable resins, and photocrosslinkable resins. Such a conductive layer can be provided by dispersing and applying these conductive powder and binder resin in a suitable solvent such as tetrahydrofuran, dichloromethane, methyl ethyl ketone, and toluene.
Further, a heat shrinkable tube in which the conductive powder is contained in a material such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, polytetrafluoroethylene-based fluororesin on a suitable cylindrical substrate. Those provided with a conductive layer can be used favorably as the conductive support of the present invention.

<< About photosensitive layer >>
Next, the charge generation layer and the charge transport layer will be described.
<About the charge generation layer>
The charge generation layer is a layer mainly composed of a charge generation material having a charge generation function, and a binder resin can be used in combination as necessary.
The charge generation layer is a layer mainly composed of a charge generation material. A known charge generation material can be used for the charge generation layer. For example, monoazo pigments, disazo pigments, asymmetrical disazo pigments, trisazo pigments, azo pigments having a carbazole skeleton (described in JP-A-53-95033), azo pigments having a distyrylbenzene skeleton (JP-A-53-133445) ), An azo pigment having a triphenylamine skeleton (described in JP-A-53-132347), an azo pigment having a diphenylamine skeleton, and an azo pigment having a dibenzothiophene skeleton (described in JP-A-54-21728) An azo pigment having a fluorenone skeleton (described in JP-A No. 54-22834), an azo pigment having an oxadiazole skeleton (described in JP-A No. 54-12742), an azo pigment having a bis-stilbene skeleton (special Described in Japanese Utility Model Laid-Open No. 54-17733), distyryloxadiazole skeleton Azo pigments such as azo pigments (described in JP-A No. 54-2129), azo pigments having a distyrylcarbazole skeleton (described in JP-A No. 54-14967), azulenium salt pigments, methine squaric acid Pigments, perylene pigments, anthraquinone or polycyclic quinone pigments, quinoneimine pigments, diphenylmethane and triphenylmethane pigments, benzoquinone and naphthoquinone pigments, cyanine and azomethine pigments, indigoid pigments, bisbenzimidazole pigments, and Examples thereof include phthalocyanine pigments such as metal phthalocyanine and metal-free phthalocyanine represented by the following general formula (7). These charge generation materials may be used alone or in combination of two or more.
Among these charge generation materials, metal phthalocyanine pigments and azo pigments described later can be used effectively.

Examples of the metal phthalocyanine pigment include metal phthalocyanines represented by the following general formula (7). These charge generation materials can be used alone or as a mixture of two or more.
(In the formula, M (central metal) represents a metal element. M (central metal) mentioned here is Li, Be, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr. , Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Ba, Hf, Ta, W , Re, Os, Ir, Pt, Au, Hg, TI, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Th, Pa, U , Np, Am, etc., or an oxide, chloride, fluoride, hydroxide, bromide, etc. The central metal is not limited to these elements.)

  The metal phthalocyanine-based charge generation material in the present invention may have a basic skeleton as represented by the general formula (7) as an example, and has a multimeric structure such as a dimer and a trimer. It may have a higher order polymer structure. In addition, the basic skeleton may have various substituents. Of these various metal phthalocyanines, titanyl phthalocyanine, chlorogallium phthalocyanine, hydroxygallium phthalocyanine, etc. having TiO as the central metal are particularly preferred in terms of photoreceptor characteristics. In addition, these metal phthalocyanines are known to have various crystal systems. For example, in the case of titanyl phthalocyanine, α, β, γ, m, Y type, etc., in the case of copper phthalocyanine, α, β, γ, etc. It has a polycrystal system of Even in a metal phthalocyanine having the same central metal, various properties change as the crystal system changes. It has been reported that the characteristics of photoreceptors using metal phthalocyanine pigments having these various crystal systems also change accordingly (Electrophotographic Society Vol. 29, No. 4, (1990)). For this reason, selection of the crystal system of metal phthalocyanine is very important in terms of photoreceptor characteristics.

  Among these metal phthalocyanine pigments, titanyl phthalocyanine pigments are effectively used, and in particular, at least 27.2 ° as a diffraction peak (± 0.2 °) with a Bragg angle 2θ with respect to the characteristic X-ray (1.542 mm) of CuKα. The titanyl phthalocyanine crystal having the maximum diffraction peak has a particularly high sensitivity, and can be used particularly effectively in the present invention because it enables high-speed image formation. Further, among them, it has a maximum diffraction peak at 27.2 °, and further has main peaks at 9.4 °, 9.6 °, and 24.0 °, and is 7.3 as the lowest diffraction peak. A titanyl phthalocyanine crystal having a peak at ゜, no peak between the 7.3 ° peak and the 9.4 ° peak, and no peak at 26.3 ° has a charge generation efficiency. It can be used very effectively as a charge generating material of the present invention, such as being large, having good electrostatic properties, and being less likely to cause scumming. These charge generation materials can be used alone or as a mixture of two or more.

  In the charge generation material, it is effective that the effect may be enhanced by making the particle size finer. In particular, in the phthalocyanine pigment, the average particle size is preferably 0.25 μm or less, and more preferably 0.2 μm or less. The manufacturing method is shown below. A method for controlling the particle size of the charge generating material contained in the photosensitive layer is a method of removing coarse particles larger than 0.25 μm after dispersing the charge generating material. The average particle size referred to here is a volume average particle size, and is determined by an ultracentrifugal automatic particle size distribution analyzer: CAPA-700 (manufactured by Horiba, Ltd.). At this time, the particle diameter (Median diameter) corresponding to 50% of the cumulative distribution was calculated. However, this method may not be able to detect a very small amount of coarse particles. Therefore, in order to obtain more details, it is important to observe the charge generation material powder or dispersion directly with an electron microscope and determine the size. It is.

  Next, a method for removing coarse particles after dispersing the charge generation material will be described. That is, it is a method in which a dispersion liquid having as fine a particle as possible is prepared and then filtered through an appropriate filter. For the preparation of the dispersion, a general method is used, and it is obtained by dispersing the charge generation material in a suitable solvent together with a binder resin, if necessary, using a ball mill, attritor, sand mill, bead mill, ultrasonic wave, or the like. It is what At this time, the binder resin may be selected depending on the electrostatic characteristics of the photoreceptor, and the solvent may be selected depending on the wettability to the pigment, the dispersibility of the pigment, and the like.

  This method is a very effective means from the viewpoint that it can be observed visually (or cannot be detected by particle size measurement), can remove the remaining trace amount of coarse particles, and has a uniform particle size distribution. Specifically, the dispersion prepared as described above is filtered through a filter having an effective pore diameter of 5 μm or less, more preferably 3 μm or less, thereby completing the dispersion. Also by this method, a dispersion containing only a charge generating substance having a small particle size (0.25 μm or less, preferably 0.2 μm or less) can be prepared. The electric characteristics are improved, the effect is sustained, and the effect of the present invention can be enhanced.

  At this time, when the particle size of the dispersion to be filtered is too large or the particle size distribution is too wide, the loss due to filtration becomes large or the filtration becomes clogged and filtration becomes impossible. There is a case. For this reason, in the dispersion before filtration, it is desirable to perform dispersion until the average particle size reaches 0.3 μm or less and the standard deviation reaches 0.2 μm or less. When the average particle size is 0.3 μm or more, the loss due to filtration increases, and when the standard deviation is 0.2 μm or more, there may be a problem that the filtration time becomes very long.

  The charge generation material has an extremely strong intermolecular hydrogen bonding force, which is a characteristic of charge generation materials exhibiting highly sensitive characteristics. For this reason, the interaction between the dispersed pigment particles is very strong. As a result, there is a great possibility that the charge generation material particles dispersed by a disperser etc. are re-aggregated by dilution or the like. Such agglomerates can be removed. At this time, since the dispersion is in a thixotropic state, particles having a size smaller than the effective pore size of the filter to be used are removed. Or the liquid which shows structural viscosity can also be changed into the state close | similar to Newton property by a filter process. Thus, the effect of the present invention can be further improved by removing the coarse particles of the charge generation material.

Among the azo pigments, azo pigments represented by the following formula (11) are effectively used. In particular, an asymmetric azo pigment in which Cp ₁ and Cp ₂ of the azo pigment are different from each other has high carrier generation efficiency and can be effectively used as the charge generation material of the present invention.
In the formula, Cp ₁ and Cp ₂ represent coupler residues. R ₂₀₁ and R ₂₀₂ each represent a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or a cyano group, and may be the same or different. Cp ₁ and Cp ₂ are represented by the following formula (12):
In the formula, R ₂₀₃ represents a hydrogen atom, an alkyl group such as a methyl group or an ethyl group, or an aryl group such as a phenyl group. R ₂₀₄ , R ₂₀₅ , R ₂₀₆ , R ₂₀₇ and R ₂₀₈ are each a hydrogen atom, a nitro group, a cyano group, a halogen atom such as fluorine, chlorine, bromine or iodine, a halogenated alkyl group such as a trifluoromethyl group, or methyl. Represents an alkyl group such as an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, a dialkylamino group or a hydroxyl group, and Z constitutes a substituted or unsubstituted aromatic carbocyclic ring or a substituted or unsubstituted aromatic heterocyclic ring Represents the atomic group necessary to

  As a binder resin used as necessary for the charge generation layer, polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, Examples include polyacrylamide, polyvinyl benzal, polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone. These binder resins can be used alone or as a mixture of two or more. The amount of the binder resin is preferably 0 to 500 parts by weight, more preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generation material. The binder resin may be added before or after dispersion.

  Moreover, as a solvent to be used, generally used organic materials such as isopropanol, acetone, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethyl cellosolve, ethyl acetate, methyl acetate, dichloromethane, dichloroethane, monochlorobenzene, cyclohexane, toluene, xylene, ligroin, etc. Among them, it is preferable to use a ketone solvent, an ester solvent, or an ether solvent. These may be used alone or in combination of two or more.

  The charge generation layer is obtained by dispersing the charge generation material in a solvent using a known dispersion method such as a ball mill, an attritor, a sand mill, a bead mill, or an ultrasonic wave together with a binder resin as necessary. Can do. The binder resin may be added before or after the charge generating material is dispersed. The coating solution for the charge generation layer is mainly composed of a charge generation material, a solvent, and a binder resin, and it contains additives such as a sensitizer, a dispersant, a surfactant, and silicone oil. May be. In some cases, it is also possible to add a charge transport material described later to the charge generation layer. The addition amount of the binder resin is usually 0 to 500 parts by weight, preferably 10 to 300 parts by weight with respect to 100 parts by weight of the charge generation material.

  The charge generation layer is formed by coating on a conductive support or an undercoat layer using the coating solution and drying. As the coating method, known methods such as dip coating, spray coating, bead coating, nozzle coating, spinner coating, ring coating, and the like can be used. The thickness of the charge generation layer is usually about 0.01 to 5 μm, preferably 0.1 to 2 μm. Further, drying after coating is performed by heating using an oven or the like. The drying temperature of the charge generation layer is preferably 50 to 160 ° C, more preferably 80 to 140 ° C.

<About the charge transport layer>
The charge transport layer is a layer having a charge transport function, and is a layer mainly composed of a charge transport material and a binder resin.
The charge transport layer of the present invention contains a hole transport material as a charge transport material, but may contain an electron transport material as necessary. Examples of each are shown below. The charge transport material means an electron transport material and a hole transport material.

Examples of the electron transporting material include chloroanil, bromanyl, tetracyanoethylene, tetracyanoquinodimethane, 2,4,7-trinitro-9-fluorenone, 2,4,5,7-tetranitro-9-fluorenone, 2,4, 5,7-tetranitroxanthone, 2,4,8-trinitrothioxanthone, 2,6,8-trinitro-4H-indeno [1,2-b] thiophen-4-one, 1,3,7-tri Examples thereof include electron-accepting substances such as nitrodibenzothiophene-5,5-dioxide, diphenoquinone derivatives, naphthalenetetracarboxylic acid diimide derivatives. These electron transport materials can be used alone or as a mixture of two or more.
Examples of hole transport materials include poly-N-vinylcarbazole and derivatives thereof, poly-γ-carbazolylethyl glutamate and derivatives thereof, pyrene-formaldehyde condensates and derivatives thereof, polyvinylpyrene, polyvinylphenanthrene, polysilane, oxazole derivatives, Oxadiazole derivatives, imidazole derivatives, monoarylamine derivatives, diarylamine derivatives, stilbene derivatives, α-phenylstilbene derivatives, diarylmethane derivatives, triarylmethane derivatives, 9-styrylanthracene derivatives, pyrazoline derivatives, divinylbenzene derivatives, hydrazone derivatives And other known substances such as indene derivatives, butadiene derivatives, pyrene derivatives, distyryl derivatives, enamine derivatives, and the like. Among hole transport materials, materials having a triarylamine structure are suitable for charge transport. These hole transport materials may be used alone or in combination of two or more.

Among the charge transport materials contained in the charge transport layer, a distyryl compound is effectively used in the present invention. A distyryl compound refers to a material having two styryl groups. Since these materials have large π conjugation and high mobility, charge transfer is likely to occur. As a result, it is considered that there is an effect of suppressing an increase in the bright portion potential as compared with a charge transport material having an equivalent ionization potential.
Further, among the distyryl compounds, a distyrylbenzene derivative represented by the following general formula (1) is particularly preferable.
[In the above formula, R _{1 to} R ₃₀ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. A substituted aryl group, an unsubstituted aryl group, an alkyl group having 1 to 4 carbon atoms or a benzyl group substituted with an alkoxy group having 1 to 4 carbon atoms may be the same or different. ]
The distyrylbenzene derivative represented by the general formula (1) has a plurality of triarylamine structures having a high charge transport function and a large π conjugation via the aromatic ring group in the center of the structural formula. In addition, since the molecular skeleton is large and the triarylamine structures are separated from each other, charge transfer is likely to occur between molecules.
The distyrylbenzene derivative used in the present invention can be synthesized by a known method such as Japanese Patent No. 2552695.

An example of the distyryl compound is given below. However, the present invention is not limited to these compounds.

Below, an example of the distyrylbenzene derivative represented by General formula (1) effective in this invention is given. However, the present invention is not limited to these compounds.

Binder resins include polystyrene, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, polyester, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, poly Vinylidene chloride, polyarylate resin, phenoxy resin, polycarbonate, cellulose acetate resin, ethyl cellulose resin, polyvinyl butyral, polyvinyl formal, polyvinyl toluene, poly-N-vinyl carbazole, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, Examples thereof include thermoplastic or thermosetting resins such as phenol resins and alkyd resins.
The amount of the charge transport material contained in the charge transport layer is preferably 20 to 300 parts by weight, more preferably 40 to 150 parts by weight with respect to 100 parts by weight of the binder resin.

  As the solvent used here, tetrahydrofuran, dioxane, toluene, dichloromethane, monochlorobenzene, dichloroethane, cyclohexanone, methyl ethyl ketone, acetone and the like are used. These may be used alone or in combination of two or more.

  If necessary, a plasticizer and a leveling agent can be added. As the plasticizer used in the charge transport layer, those used as general plasticizers such as dibutyl phthalate and dioctyl phthalate can be used as they are, and the amount used is 0 to 30 weights with respect to 100 parts by weight of the binder resin. Part is appropriate. Examples of leveling agents that can be used in the charge transport layer include silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, and polymers or oligomers having a perfluoroalkyl group in the side chain. About 0 to 1 part by weight is appropriate for the part by weight.

  The thickness of the charge transport layer is preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of resolution and responsiveness. The lower limit varies depending on the system to be used (particularly charging potential), but is preferably 5 μm or more.

<About other additives>
In the present invention, each layer such as a cross-linked charge transport layer, a charge generation layer, a charge transport layer, an undercoat layer, and an intermediate layer is provided for the purpose of improving the stability of image quality in order to improve environmental resistance. An antioxidant can be added to the.

The following are mentioned as antioxidant which can be used for this invention.
<Phenolic compound>
2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-t-butyl-4-ethylphenol, stearyl-β- (3,5-di-t-butyl-4 -Hydroxyphenyl) propionate, 2,2'-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2'-methylene-bis- (4-ethyl-6-tert-butylphenol), 4, 4'-thiobis- (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis- (3-methyl-6-tert-butylphenol), 1,1,3-tris- (2-methyl-4 -Hydroxy-5-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis- [meth -3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, bis [3,3'-bis (4'-hydroxy-3'-t-butylphenyl) buty Rick acid] glycol ester, tocopherols and the like.

<Paraphenylenediamines>
N-phenyl-N'-isopropyl-p-phenylenediamine, N, N'-di-sec-butyl-p-phenylenediamine, N-phenyl-N-sec-butyl-p-phenylenediamine, N, N'- Di-isopropyl-p-phenylenediamine, N, N'-dimethyl-N, N'-di-t-butyl-p-phenylenediamine and the like.
<Hydroquinones>
2,5-di-t-octylhydroquinone, 2,6-didodecylhydroquinone, 2-dodecylhydroquinone, 2-dodecyl-5-chlorohydroquinone, 2-t-octyl-5-methylhydroquinone, 2- (2-octadecenyl) ) -5-methylhydroquinone and the like.
<Organic sulfur compounds>
Dilauryl-3, 3'-thiodipropionate, distearyl-3, 3'-thiodipropionate, ditetradecyl-3, 3'-thiodipropionate and the like.
<Organic phosphorus compounds>
Triphenylphosphine, tri (nonylphenyl) phosphine, tri (dinonylphenyl) phosphine, tricresylphosphine, tri (2,4-dibutylphenoxy) phosphine, and the like.

These compounds are known as antioxidants such as rubbers, plastics and fats and oils, and commercially available products can be easily obtained.
The addition amount of the antioxidant in the present invention is preferably 0.01 to 10 parts by weight with respect to the total weight of the layer to be added.

<< About the crosslinkable charge transport layer >>
In the photosensitive layer and the cross-linked charge transport layer of the invention, the arylmethane compounds represented by the general formulas (2) to (5) described in JP-A-2007-27968 and the general formula described in JP-A-2007-272192 ( The compound of 2) and the compounds described in the general formulas (2) and (3) described in JP-A-2007-272191 may be contained. Since these compounds have an antioxidant function and a charge transport function, they are useful compounds.

Next, the constituent material of the crosslinkable charge transport layer of the present invention will be described.
Since the crosslinkable charge transport layer needs to transport charges while maintaining abrasion resistance, a radical polymerizable monomer that does not have a charge transport structure or a radical polymerizable oligomer that does not have a charge transport structure and a charge It is made from a radically polymerizable compound having a transporting structure and a copolymer comprising at least one cyclic structure in at least one repeating unit of the two or more repeating units. More preferably, the cyclic structure of the copolymer is a saturated bond between carbon atoms, and the number of carbon atoms constituting the cyclic structure is 6 or more. The “oligomer” in the present specification refers to a polymer having a repeating unit and having 2 to 10 repeating units.
The crosslinkable charge transport layer is cured and has excellent mechanical durability. Furthermore, it is excellent in releasability. Although the reason is not clear at this time, it is thought that the reason why the releasability is excellent is that the copolymer is separated into layers and has a fine sea-island structure on the surface. With this structure, it is considered that the contact area with the toner and foreign matter is reduced and the adhesion is reduced.

Curing is generally an intermolecular reaction of a low-molecular compound having a plurality of functional groups or a high-molecular compound is bonded (for example, covalent bond) between molecules by applying energy such as heat, light, electron beam, etc. This reaction forms an original network structure.
A radical polymerizable monomer or oligomer having no charge transporting structure is a kind of curable resin. Examples of the curable resin include a thermosetting resin that is polymerized by heat, a photocurable resin that is polymerized by light such as ultraviolet rays and visible light, an electron beam curable resin that is polymerized by electronic properties, and a curing agent as necessary. Or a catalyst, a polymerization initiator, or the like.

  In order to cure the curable resin, it is necessary that a reactive compound (for example, a monomer or an oligomer) has a functional group that causes a polymerization reaction. Examples of these functional groups include acryloyl groups and / or methacryloyl groups. Further, in the curing reaction, the larger the number of functional groups in one molecule of the reactive monomer, the stronger the three-dimensional network structure becomes, and the trifunctional or higher functionality is particularly effective. As a result, the curing density is increased, the hardness is high, the elasticity is high, the uniformity is smooth, and the smoothness is improved. This is effective for improving the durability and image quality of the photoreceptor.

  In the present invention, the radically polymerizable monomer or oligomer having no charge transporting structure on the conductive support and the reactive compound having the charge transporting structure are cured and reacted as described above three-dimensionally. Forms a developed network structure. In this case, it is possible to further increase the degree of curing by previously mixing a curing agent, a catalyst, a polymerization initiator and the like, which is particularly effective in the present invention. As a result, the wear resistance of the cross-linked charge transport layer is further improved, and unreacted functional groups are less likely to remain, which is effective in improving the wear resistance and suppressing the deterioration of electrostatic characteristics. In addition, since the reaction is uniform, cracks and distortion are less likely to occur.

<Regarding radically polymerizable monomer and oligomer having no charge transporting structure>
The radical polymerizable monomer or oligomer having no charge transporting structure has a hole transporting structure such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group or nitro group. A monomer or oligomer that does not have an electron transport structure such as an electron-withdrawing aromatic ring and has a radical polymerizable functional group. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization. Examples of these radical polymerizable functional groups include 1-substituted ethylene functional groups and 1,1-substituted ethylene functional groups shown below.

(1) 1-Substituted Ethylene Functional Group Examples of the 1-substituted ethylene functional group include functional groups represented by the following formulas.
CH ₂ = CH—X ₁ −... Formula (I)
(In the formula, X ₁ is an arylene group such as a phenylene group or a naphthylene group which may have a substituent, an alkenylene group which may have a substituent, a —CO— group, a —COO— group. , -CONR ₇₈ group (R ₇₈ represents an alkyl group such as hydrogen, methyl group or ethyl group, an aralkyl group such as benzyl group, naphthylmethyl group or phenethyl group, or an aryl group such as phenyl group or naphthyl group). Or -S- group.)
Specific examples of these substituents include vinyl group, styryl group, 2-methyl-1,3-butadienyl group, vinylcarbonyl group, acryloyloxy group, acryloylamide group, vinylthioether group and the like.

(2) 1,1-Substituted Ethylene Functional Group Examples of the 1,1-substituted ethylene functional group include functional groups represented by the following formulas.
_{CH 2 = CY-X 2 -} ···· formula (II)
(In the formula, Y is an aryl group such as an alkyl group which may have a substituent, an aralkyl group which may have a substituent, a phenyl group which may have a substituent, or a naphthyl group. Group, halogen atom, cyano group, nitro group, alkoxy group such as methoxy group or ethoxy group, -COOR ₇₉ group (R ₇₉ is a hydrogen atom, an alkyl such as an optionally substituted methyl group or ethyl group) Group, an aralkyl group such as benzyl and phenethyl group which may have a substituent, an aryl group such as a phenyl group and a naphthyl group which may have a substituent, or -CONR ₈₀ R ₈₁ (R ₈₀ and R ₈₁ is a hydrogen atom, an alkyl group such as an optionally substituted methyl group, an ethyl group, an aralkyl group such as an optionally substituted benzyl group, naphthylmethyl group, or phenethyl group, or Place A phenyl group which may have a group, an aryl group such as phenyl or naphthyl, which may be the same or different from each other.) Further, X ₂ is and the same substituents as X ₁ in the formula (I) Represents a single bond or an alkylene group, provided that at least one of Y and X ₂ is an oxycarbonyl group, a cyano group, an alkenylene group, and an aromatic ring.)
Specific examples of these substituents include an α-acryloyloxy chloride group, a methacryloyloxy group, an α-cyanoethylene group, an α-cyanoacryloyloxy group, an α-cyanophenylene group, and a methacryloylamino group.

In addition, examples of the substituent further substituted with the substituent for X ₁ , X ₂ , and Y include alkyl groups such as halogen atom, nitro group, cyano group, methyl group, and ethyl group, methoxy group, and ethoxy group. And an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group and a naphthyl group, and an aralkyl group such as a benzyl group and a phenethyl group.

  Among these radical polymerizable functional groups, acryloyloxy group and methacryloyloxy group are particularly useful. The number of functional groups of the radically polymerizable monomer or oligomer having no charge transporting structure is preferably polyfunctional and more preferably trifunctional or higher. When a tri- or higher functional radically polymerizable monomer or oligomer is cured, a three-dimensional network structure is developed, and a high hardness and high elasticity layer having a very high crosslink density is obtained, which has high wear resistance and scratch resistance. Achieved. However, depending on the curing conditions and the materials used, a large number of bonds are instantaneously formed in the curing reaction, so that internal stress due to volume shrinkage occurs, and cracks and film peeling may easily occur. In that case, it may be improved by using a monofunctional or bifunctional radically polymerizable compound or by mixing them.

In the following, trifunctional or higher functional radical polymerizable monomers and oligomers that do not have a charge transporting structure effective for improving wear resistance will be described.
A compound having three or more acryloyloxy groups is obtained by, for example, using a compound having three or more hydroxyl groups in the molecule, acrylic acid (salt), acrylic acid halide, or acrylic ester, and performing an ester reaction or a transesterification reaction. Can be obtained. A compound having three or more methacryloyloxy groups can be obtained in the same manner. Further, the radical polymerizable functional groups in the monomer having three or more radical polymerizable functional groups may be the same or different.

Examples of the radically polymerizable monomer having no charge transporting structure include the following, but are not limited to these compounds.
That is, the radical polymerizable monomer having no charge transporting structure used in the present invention includes trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate, HPA-modified trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate. Acrylate, PO-modified trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, ECH-modified trimethylolpropane triacrylate, HPA-modified trimethylolpropane trimethacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate (PETTA), glycerol triacrylate , ECH-modified glycerol triacrylate, EO-modified glyce Triacrylate, PO-modified glycerol triacrylate, tris (acryloxyethyl) isocyanurate, alkyl-modified dipentaerythritol tetraacrylate, alkyl-modified dipentaerythritol triacrylate, dimethylolpropane tetraacrylate (DTMPTA), pentaerythritol ethoxytetraacrylate, EO-modified phosphoric acid triacrylate, 2,2,5,5, -tetrahydroxymethylcyclopentanone tetraacrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl Carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, chic Hexyl acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, styrene monomer, 1,3-butanediol diacrylate, 1,4-butanediol di Acrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, EO-modified bisphenol A diacrylate, EO-modified bisphenol F Examples include diacrylate and neopentyl glycol diacrylate. Examples include trimethylolpropane triacrylate (TMPTA), HPA-modified trimethylolpropane triacrylate, EO-modified trimethylolpropane triacrylate, PO-modified trimethylolpropane triacrylate, and ECH-modified trimethylolpropane triacrylate. It is not limited to this. In addition, ethyleneoxy modification is described as EO modification, propyleneoxy modification as PO modification, epichlorohydrin modification as ECH modification, and alkylene modification as HPA modification.
Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.
These may be used alone or in combination of two or more.

  In addition, the trifunctional or higher functional radical polymerizable monomer or oligomer having no charge transporting structure used in the present invention includes the monomer or oligomer in order to form a dense crosslink in the crosslinkable charge transporting layer. The ratio of molecular weight to the number of functional groups (molecular weight / number of functional groups) is preferably 250 or less. Further, when this ratio is larger than 250, the cross-linked charge transport layer is soft and wear resistance is somewhat lowered. Therefore, among monomers exemplified above, monomers having a modifying group such as EO, PO, caprolactone, etc. It is not preferable to use a compound having a long modifying group alone.

Trifunctional or higher radical polymerizable monomers and radical polymerizable oligomers having no charge transport structure are particularly effective for increasing the hardness of the film, but monofunctional and bifunctional radical polymerizable monomers and radical polymerizable oligomers are used. It is also possible and may be very effective depending on the material. Known radical polymerizable monomers and oligomers can be used.
Examples of the monofunctional radically polymerizable monomer include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, tetrahydrofurfuryl acrylate, 2-ethylhexyl carbitol acrylate, 3-methoxybutyl acrylate, benzyl acrylate, Examples include cyclohexyl acrylate, isoamyl acrylate, isobutyl acrylate, methoxytriethylene glycol acrylate, phenoxytetraethylene glycol acrylate, cetyl acrylate, isostearyl acrylate, stearyl acrylate, and styrene monomer.
Examples of the bifunctional radical polymerizable monomer include 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1, Examples include 6-hexanediol dimethacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, bisphenol A-EO modified diacrylate, bisphenol F-EO modified diacrylate, and neopentyl glycol diacrylate.

Other monomers include, for example, those substituted with fluorine atoms such as octafluoropentyl acrylate, 2-perfluorooctylethyl acrylate, 2-perfluorooctylethyl methacrylate, 2-perfluoroisononylethyl acrylate, and Japanese Patent Publication No. 5-60503. And acryloyl polydimethylsiloxane ethyl of 20 to 70, methacryloyl polydimethylsiloxane ethyl, acryloyl polydimethylsiloxane propyl, acryloyl polydimethylsiloxane butyl, diacryloyl polydimethylsiloxane diethyl And vinyl monomers having a polysiloxane group such as acrylate and methacrylate, and methacrylic acid.
Examples of the radical polymerizable oligomer include epoxy acrylate, urethane acrylate, and polyester acrylate oligomers.

And a copolymer comprising at least one cyclic structure in at least one repeating unit of two or more repeating units used in the crosslinked charge transporting layer, The component ratio of the radically polymerizable monomer having no structure and / or the radically polymerizable oligomer having no charge transporting structure is 20 to 80% by weight, preferably 30 to 70% by weight based on the total amount of the crosslinkable charge transporting layer. %. When the total of these is less than 20% by weight, the three-dimensional cross-linking density of the cross-linked charge transport layer is small, and a drastic improvement in wear resistance is not achieved as compared with the case of using a conventional thermoplastic binder resin. On the other hand, if it exceeds 80% by weight, the content of the charge transporting compound is lowered, and the electrical characteristics are deteriorated. The electrical characteristics and abrasion resistance required differ depending on the process used, and the film thickness of the cross-linked charge transport layer of the photoreceptor varies accordingly. A range of 70% by weight is most preferred.
Moreover, the first component is preferably 0.1% or more and 10% or less by weight with respect to the total amount of the first component, the second component, and the third component. When the weight ratio is less than 0.1%, the releasability tends to be slightly lowered. This is considered to be because the layer separation of the film becomes insufficient and it becomes difficult to form fine irregularities. If it exceeds 10%, the residual potential tends to increase slightly. This is presumably because the charge transport property of the film is slightly lowered.

<Regarding a Copolymer Composed of Two or More Repeating Units and Containing at least One Cyclic Structure in at least One Repeating Unit of the Two or More Repeating Units>
Subsequently, a copolymer comprising two or more repeating units and containing at least one kind of cyclic structure in at least one repeating unit of the two or more repeating units will be described. The copolymer may be any copolymer as long as it is composed of two or more repeating units and contains at least one cyclic structure in at least one repeating unit of the two or more repeating units.

The copolymer comprising at least one repeating unit used in the present invention and containing at least one cyclic structure in at least one repeating unit of the two or more repeating units is a radical containing at least one cyclic structure. It can be produced by mixing two or more radically polymerizable monomers including a polymerizable monomer, a polymerization initiator and a solvent, which will be described later, and reacting at a high temperature. The radical polymerizable group of the radical polymerizable monomer preferably has an acryloyl group and / or a methacryloyl group. Further, the copolymer preferably has a long chain shape from the viewpoint of releasability. Therefore, the copolymer material is preferably monofunctional or bifunctional.
As the polymerization initiator, a photopolymerization initiator or a thermal polymerization initiator can be used. Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. That is, the same initiators as those described later for the cross-linked charge transport layer can be used. As the solvent for copolymer synthesis, the same solvent as the coating solution for a crosslinkable charge transport layer described later can be used.

  The copolymer of the first component in the present invention may not have a functional group that reacts, but preferably has a functional group that reacts with the second component and is incorporated into a crosslinked structure. If there is a functional group that reacts with each other, the maintenance of the surface shape is enhanced, and mechanical durability and high releasability are maintained. In the present invention, the first component has a functional group having an unsaturated double bond that reacts with one or more radically polymerizable compounds not having a charge transporting structure selected from the group consisting of the aforementioned monomers or oligomers. It is desirable. The unsaturated double bond of the present invention refers to a bond having a radical polymerizable functional group. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and can be radically polymerized. In the case of having a radical polymerizable functional group, the film structure is strengthened by crosslinking with the second component or the third component, so that the wear resistance is easily improved. Among the functional groups having an unsaturated double bond, an acryloyloxy group and a methacryloyloxy group are particularly useful, and each preferably has an acryloyl group and / or a methacryloyl group.

  The repeating unit of the copolymer used in the present invention is preferably 2 or more and 10 or less in order to improve releasability. When the number of repeating units is 1 or 11 or more, it is difficult to control the layer separation state, and sufficient releasability may not be exhibited. The repeating unit having a cyclic structure is preferably 1 or more and 5 or less. Even when it does not have a ring structure or when it is 6 or more, it is difficult to control the layer separation state, and sufficient releasability may not be exhibited.

The material for incorporating a cyclic structure into the copolymer may be any cyclic compound having a radical polymerizable functional group and may take a cyclic structure during the polymerization reaction. Preferably, the cyclic structure is composed of carbon-carbon bonds, and the number of carbon atoms constituting the cyclic structure is 6 or more. More preferred are an adamantane ring, a norbornane ring, and a cyclohexyl ring. The release structure was excellent when the cyclic structure was composed of carbon-carbon bonds and the number of carbon atoms constituting the cyclic structure was 6 or more. Further, those having an adamantane ring, norbornane ring, or cyclohexyl ring structure were further excellent in wear resistance and releasability.
The example of the cyclic compound of the material of the copolymer used for this invention below is shown. The scope of the present invention is not limited to the following materials.

  In addition to the above, the above-mentioned radical polymerizable monomer can be used as the copolymer material. As these radically polymerizable monomers, radically polymerizable monomers having no charge transporting structure as described above can also be used. Among these radical polymerizable monomers, monofunctional ones are preferable from the viewpoint of releasability. Although the reason is not clear at the present time, as a copolymer material, in addition to a radical polymerizable monomer having a cyclic structure and a radical polymerizable monomer not having a cyclic structure, methacrylic acid is included, and thus the releasability is increased. This is thought to promote layer separation and contribute to the formation of fine irregularities.

The copolymerization ratio of the cyclic compound is preferably from 0.3 to 0.9 in terms of molar ratio. If the copolymerization ratio is less than 0.3, the releasability may be insufficient. This is considered to be because the layer separation is insufficient and a smooth membrane is easily formed. In order to provide sufficient releasability, 0.3 or more is preferable. If the copolymerization ratio exceeds 0.9, the mechanical strength of the film may be inferior. In order to balance the mechanical strength and releasability of the film, the copolymerization ratio of the cyclic compound is more preferably from 0.5 to 0.9.
The weight average molecular weight of the copolymer is preferably 2000 to 100,000. This is considered to be because phase separation is easy to proceed within this range.

<Regarding a radically polymerizable compound having a charge transporting structure>
Examples of the radical polymerizable compound having a charge transport structure used in the present invention include hole transport structures such as triarylamine, hydrazone, pyrazoline, carbazole, such as condensed polycyclic quinone, diphenoquinone, cyano group and nitro group. It refers to a compound having an electron transport structure such as an electron-withdrawing aromatic ring and having a radical polymerizable functional group. The radical polymerizable functional group may be any group as long as it has a carbon-carbon double bond and is capable of radical polymerization.

  Any number of functional groups can be used as the radical polymerizable compound having a charge transport structure used in the cross-linked charge transport layer of the present invention. From the point of view, it is more preferable. In the case of bifunctional, the crosslink structure is fixed by a plurality of bonds and the crosslink density is further increased. However, since the charge transporting structure is very bulky, the distortion of the cured layer structure is increased and the internal stress of the layer may be increased. is there. In addition, the intermediate structure (cation radical) at the time of charge transport cannot be kept stable, and there is a risk that a decrease in sensitivity due to charge trapping and an increase in residual potential are likely to occur. This tendency is particularly remarkable for those having three or more functional groups.

As the charge transporting structure of the radical polymerizable compound having a charge transporting structure, any material can be used as long as it can provide a charge transporting function. Among them, the triarylamine structure is highly effective and useful. is there. This is considered to be because there are many hopping sites and π conjugation spreads. Triarylamines are easily conjugated to each other in the radical cation state. For these reasons, the triarylamine structure is excellent in the charge transport function. In particular, when the compound represented by the formula (2) or (3) is used, electrical characteristics such as sensitivity and residual potential are favorably sustained.
[Wherein, R ₄₀ represents a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, an aryl group which may have a substituent, a cyano group, a nitro group, A group, an alkoxy group, —COOR ₄₁ (R ₄₁ represents a hydrogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent, or an aryl group which may have a substituent. ), A halogenated carbonyl group or CONR ₄₂ R ₄₃ (R ₄₂ and R ₄₃ have a hydrogen atom, a halogen atom, an alkyl group which may have a substituent, an aralkyl group which may have a substituent or a substituent. Represents an aryl group which may be the same or different, and Ar ₂ and Ar ₃ represent a substituted or unsubstituted arylene group, which may be the same or different. . Ar ₄ and Ar ₅ represent a substituted or unsubstituted aryl group, and may be the same or different. X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group. Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group. m and n represent an integer of 0 to 3. ]

Below, the specific example of the substituent in general formula (2), (3) is shown.
In the general formulas (2) and (3), in the substituent of R ₄₀ , examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group, and examples of the aryl group include a phenyl group and a naphthyl group. The aralkyl group includes a benzyl group, a phenethyl group, and a naphthylmethyl group, and the alkoxy group includes a methoxy group, an ethoxy group, a propoxy group, and the like. These include a halogen atom, a nitro group, a cyano group, and a methyl group. Substituted with an alkyl group such as an ethyl group, an alkoxy group such as a methoxy group or an ethoxy group, an aryloxy group such as a phenoxy group, an aryl group such as a phenyl group or a naphthyl group, an aralkyl group such as a benzyl group or a phenethyl group, etc. May be.
Of the substituents for R ₄₀ , particularly preferred are a hydrogen atom and a methyl group.

Ar ₄ and Ar ₅ are substituted or unsubstituted aryl groups. In the present invention, the aryl group includes a condensed polycyclic hydrocarbon group, a non-fused cyclic hydrocarbon group, and a heterocyclic group.
The condensed polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentanyl group, an indenyl group, a naphthyl group, an azulenyl group, a heptaenyl group, a biphenylenyl group, an as-indacenyl group. , S-indacenyl group, fluorenyl group, acenaphthylenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrylenyl group, triphenylyl group, pyrenyl group , A chrycenyl group, a naphthacenyl group, and the like. Examples of the non-condensed cyclic hydrocarbon group include monovalent groups of monocyclic hydrocarbon compounds such as benzene, diphenyl ether, polyethylene diphenyl ether, diphenyl thioether and diphenyl sulfone, or biphenyl, polyphenyl, diphenylalkane, diphenylalkene, diphenylalkyne, Monovalent groups of non-condensed polycyclic hydrocarbon compounds such as triphenylmethane, distyrylbenzene, 1,1-diphenylcycloalkane, polyphenylalkane, and polyphenylalkene, or ring assemblies such as 9,9-diphenylfluorene And monovalent groups of hydrocarbon compounds. Examples of the heterocyclic group include monovalent groups such as carbazole, dibenzofuran, dibenzothiophene, oxadiazole, and thiadiazole.

In addition, the aryl group represented by Ar ₄ or Ar ₅ may have a substituent as shown below, for example.
(1) Halogen atom, cyano group, nitro group and the like.
(2) an alkyl group;
Preferably, it is a C1-C12, particularly C1-C8, more preferably a C1-C4 linear or branched alkyl group, and these alkyl groups further include a fluorine atom, a hydroxyl group, a cyano group, and a C1-C4 alkoxy group. , A phenyl group or a halogen atom, a C1-C4 alkyl group or a C1-C4 alkoxy group substituted with a phenyl group.
Specifically, methyl group, ethyl group, n-butyl group, i-propyl group, t-butyl group, s-butyl group, n-propyl group, trifluoromethyl group, 2-hydroxyethyl group, 2-ethoxyethyl Group, 2-cyanoethyl group, 2-methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-phenylbenzyl group and the like.

(3) an alkoxy group (—OR ₈₂ );
(In the formula, R ₈₂ represents an alkyl group defined in (2).)
Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, benzyloxy group And a trifluoromethoxy group.
(4) aryloxy group;
Examples of the aryl group include a phenyl group and a naphthyl group. This may contain a C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom as a substituent. Specific examples include a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methoxyphenoxy group, and a 4-methylphenoxy group.
(5) an alkyl mercapto group or an aryl mercapto group;
Specific examples include a methylthio group, an ethylthio group, a phenylthio group, and a p-methylphenylthio group.

(6) a substituent represented by the following formula;
(Wherein R _d and R _e each independently represents a hydrogen atom, an alkyl group defined in (2) above, or an aryl group. Examples of the aryl group include a phenyl group, a biphenyl group, and a naphthyl group, These may contain a C1-C4 alkoxy group, a C1-C4 alkyl group or a halogen atom as a substituent, and R _d and R _e may form a ring together.)
Specifically, amino group, diethylamino group, N-methyl-N-phenylamino group, N, N-diphenylamino group, N, N-di (tolyl) amino group, dibenzylamino group, piperidino group, morpholino group And pyrrolidino group.

(7) An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.
(8) A substituted or unsubstituted styryl group, a substituted or unsubstituted β-phenylstyryl group, a diphenylaminophenyl group, a ditolylaminophenyl group, and the like.

Examples of the arylene group represented by Ar ₂ and Ar ₃ include a divalent group derived from the aryl group represented by Ar ₄ and Ar ₅ .
X represents a single bond, a substituted or unsubstituted alkylene group, a substituted or unsubstituted cycloalkylene group, a substituted or unsubstituted alkylene ether group, an oxygen atom, a sulfur atom, or a vinylene group.
The substituted or unsubstituted alkylene group is a C1-C12, preferably C1-C8, more preferably a C1-C4 linear or branched alkylene group, and these alkylene groups further include a fluorine atom, a hydroxyl group, It may have a cyano group, a C1-C4 alkoxy group, a phenyl group or a halogen atom, a C1-C4 alkyl group, or a phenyl group substituted with a C1-C4 alkoxy group. Specifically, methylene group, ethylene group, n-butylene group, i-propylene group, t-butylene group, s-butylene group, n-propylene group, trifluoromethylene group, 2-hydroxyethylene group, 2-ethoxyethylene. Group, 2-cyanoethylene group, 2-methoxyethylene group, benzylidene group, phenylethylene group, 4-chlorophenylethylene group, 4-methylphenylethylene group, 4-biphenylethylene group and the like.

The substituted or unsubstituted cycloalkylene group is a C5-C7 cyclic alkylene group, and these cyclic alkylene groups have a fluorine atom, a hydroxyl group, a C1-C4 alkyl group, and a C1-C4 alkoxy group. May be. Specific examples include a cyclohexylidene group, a cyclohexylene group, and a 3,3-dimethylcyclohexylidene group.
Examples of the substituted or unsubstituted alkylene ether group include alkyleneoxy groups such as ethyleneoxy group and propyleneoxy group, alkylenedioxy groups derived from ethylene glycol, propylene glycol, and the like, diethylene glycol, tetraethylene glycol, tripropylene glycol, and the like. Examples thereof include a derived di- or poly (oxyalkylene) oxy group, and the alkylene group of the alkylene ether group may have a substituent such as a hydroxyl group, a methyl group, or an ethyl group.

Examples of the vinylene group include substituents represented by the following general formula.
[Wherein, R _f is hydrogen, an alkyl group (the same as the alkyl group defined in (2) above), an aryl group (the same as the aryl group represented by Ar ₄ or Ar ₅ above), a is 1 or 2, b represents 1-3. ]

Z represents a substituted or unsubstituted alkylene group, a substituted or unsubstituted alkylene ether group, or an alkyleneoxycarbonyl group.
Examples of the substituted or unsubstituted alkylene group include the same alkylene groups as those described above for X.
Examples of the substituted or unsubstituted alkylene ether group include the alkylene ether group represented by X.
Examples of the alkyleneoxycarbonyl group include a caprolactone-modified group.

Further, the radical polymerizable compound having a monofunctional charge transport structure of the present invention is more preferably a compound having a structure represented by the following general formula (10).
(In the formula, o, p and q are each an integer of 0 or 1, R _a represents a hydrogen atom or a methyl group, and R _b and R _c represent a substituent other than a hydrogen atom and an alkyl group having 1 to 6 carbon atoms. In the case of plural, s and t each represent an integer of 0 to 3. Za is a single bond, a methylene group, an ethylene group,
Represents. )
As the compound represented by the general formula (10), compounds having a methyl group or an ethyl group as substituents for R _b and R _c are particularly preferable.

  The radically polymerizable compound having a monofunctional charge transporting structure represented by the general formulas (2) and (3), particularly (10) used in the present invention has a carbon-carbon double bond opened on both sides. In order to polymerize, it does not become a terminal structure, but is incorporated in a chain polymer and crosslinked by polymerization with a radical polymerizable monomer having no charge transport structure. Exists in the cross-linked chain between the main chain and the main chain (in this cross-linked chain, an intermolecular cross-linked chain between one polymer and another polymer and a folded state in one polymer) There is an intramolecular cross-linked chain in which a site with a main chain and another site derived from a polymerized monomer are cross-linked at a position away from this in the main chain), but even if it exists in the main chain Even if it is present in the cross-linked chain, the triarylamine suspended from the chain part The structure has at least three aryl groups arranged in a radial direction from the nitrogen atom and is bulky, but is not directly bonded to the chain part and is suspended from the chain part via a carbonyl group or the like. Since these triarylamine structures can be arranged adjacent to each other in the polymer, the structural distortion in the molecule is small. In the case of a cross-linked charge transport layer of an electrophotographic photoreceptor, it is presumed that an intramolecular structure relatively free from interruption of the charge transport path can be taken.

Specific examples of the radical polymerizable compound having a charge transporting structure used in the present invention are shown below, but are not limited to the compounds having these structures.

  The radical polymerizable compound having a charge transporting structure used in the present invention is 20 to 80% by weight, preferably 30 to 70% by weight, based on the total amount of the cross-linked charge transport layer. If this component is less than 20% by weight, the charge transport performance of the crosslinkable charge transport layer cannot be maintained sufficiently, and deterioration of electrical characteristics such as a decrease in sensitivity and an increase in residual potential will occur with repeated use. On the other hand, if it exceeds 80% by weight, the content of the radically polymerizable monomer and / or oligomer having no charge transport structure is lowered, resulting in a decrease in the crosslink density and high wear resistance is not exhibited. Although the electrical characteristics and abrasion resistance required differ depending on the process used, it cannot be said unconditionally, but considering the balance of both characteristics, the range of 30 to 70% by weight is most preferable.

<About the initiator>
The cross-linked charge transport layer of the present invention comprises the following three components. First component: a copolymer comprising two or more repeating units, wherein at least one repeating unit of the two or more repeating units contains at least one kind of cyclic structure, second component: having a charge transporting structure Radical polymerizable monomer and / or radical polymerizable oligomer having no charge transport structure, third component: radical polymerizable compound having at least one charge transport structure. These are cross-linked charge transport layers that are cured simultaneously using at least one of heat, light, and ionizing radiation. Necessary when forming a cross-linkable charge transport layer using heat energy or light energy. Accordingly, a polymerization initiator may be used in the crosslinkable charge transport layer in order to allow the crosslink reaction to proceed efficiently. When performing crosslinking using ionizing radiation, it is usually possible to obtain a crosslinking reaction without using a polymerization initiator, but in order to cure the uncured components remaining after irradiation with ionizing radiation, as a post-treatment Thermal energy and / or light energy can be applied, and even in that case, it is effective to add a polymerization initiator shown below.

  Examples of the thermal polymerization initiator include 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, benzoyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di ( Peroxybenzoyl) hexyne-3, di-t-butyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, peroxide initiators such as lauroyl peroxide, azobisisobutylnitrile, azobiscyclohexanecarbonitrile Azo initiators such as methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, 4,4′-azobis-4-cyanovaleric acid.

  Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 4- (2-hydroxyethoxy) phenyl- (2 -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2- Acetophenone-based or ketal-based photopolymerization initiators such as methyl-2-morpholino (4-methylthiophenyl) propan-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, Benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether Benzoin ether photopolymerization initiators such as benzoin isopropyl ether, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2-benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylated benzophenone, Benzophenone photopolymerization initiators such as 1,4-benzoylbenzene, thioxanthones such as 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone Photopolymerization initiator, bis (cyclopentadienyl) -di-chloro-titanium, bis (cyclopentadienyl) -di-phenyl-titanium, bis (cyclopentadienyl) -bis ( , 3,4,5,6 pentafluorophenyl) titanium, bis (cyclopentadienyl) -bis (2,6-difluoro-3- (pyrrol-1-yl) phenyl) titanium, etc. Other photopolymerization initiators include ethyl anthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenyl Phosphine oxide, bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglyoxyester, 9,10-phenanthrene, acridine compound, triazine compound, imidazole compound Be .

  Moreover, what has a photopolymerization acceleration effect can also be used individually or in combination with the said photoinitiator. Examples include triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, (2-dimethylamino) ethyl benzoate, 4,4'-dimethylaminobenzophenone, and the like. These polymerization initiators may be used alone or in combination of two or more. The content of the polymerization initiator is 0.5 to 40 parts by weight, preferably 1 to 20 parts by weight with respect to 100 parts by weight of the total content having radical polymerizability.

<About filler addition>
The crosslinked charge transport layer of the present invention can contain filler fine particles for the purpose of improving wear resistance, stable layer separation and imparting functionality.
The filler fine particle-containing crosslinked charge transport layer of the present invention has a high crosslinking density, and has higher abrasion resistance of the resin portion than the non-crosslinked filler-containing binder resin layer, and the above uneven wear is suppressed. In addition to this, the filler fine particles dispersed in the resin are caught by the cured resin cross-linked matrix, and since the filler holding power of the cross-linked matrix is large, the filler is prevented from falling off. Therefore, it is considered that the wear resistance is greatly enhanced. Further, it is considered that the filler has an effect of stably generating layer separation.

  As the filler fine particles, the following can be used. Examples of the organic filler material include fluorine resin powder such as polytetrafluoroethylene, silicone resin powder, and carbon fine particles. The carbon fine particles are particles having a structure mainly composed of carbon, and are particles having a structure such as amorphous, diamond, graphite, amorphous carbon, fullerene, zeppelin, carbon nanotube, carbon nanohorn. Among these structures, particles containing hydrogen-containing diamond-like carbon or amorphous carbon structure have good mechanical and chemical durability. The diamond-like carbon or amorphous carbon film containing hydrogen is a particle in which similar structures such as a diamond structure having an SP3 orbit, a graphite structure having an SP2 orbit, and an amorphous carbon structure are mixed. Diamond-like carbon or amorphous carbon fine particles are not limited to carbon, but may contain other elements such as hydrogen, oxygen, nitrogen, fluorine, boron, phosphorus, chlorine, bromine and iodine. Absent.

  Examples of inorganic filler materials include metal powders such as copper, tin, aluminum, and indium, metal oxides such as silicon oxide, tin oxide, zinc oxide, titanium oxide, indium oxide, antimony oxide, and bismuth oxide, and potassium titanate. An inorganic material is mentioned. In particular, it is advantageous to use an inorganic material among them from the viewpoint of the hardness of the filler. In particular, metal oxides are good, and silicon oxide, aluminum oxide, and titanium oxide can be used effectively. Also, fine particles such as colloidal silica and colloidal alumina can be used effectively.

  The average primary particle size of the filler is preferably 0.01 to 0.9 μm from the viewpoint of light transmittance and wear resistance of the cross-linked charge transport layer, and more preferably 0.1 μm to 0.5 μm. When the average primary particle size of the filler is 0.01 μm or less, it causes a decrease in wear resistance, a decrease in dispersibility, etc., and when it is 0.9 μm or more, the sedimentation property of the filler is promoted in the dispersion liquid. In addition, toner filming may occur.

  The higher the filler material concentration in the cross-linked charge transport layer, the better the wear resistance, but if it is too high, the residual potential will increase, the writing light transmittance of the surface layer will decrease, causing side effects There is. Therefore, it is about 50% by weight or less, preferably about 30% by weight or less based on the total solid content. Furthermore, these fillers can be surface-treated with at least one kind of surface treatment agent, and it is preferable from the viewpoint of dispersibility of the fillers. Decreasing the dispersibility of the filler not only increases the residual potential, but also decreases the transparency of the coating, causes defects in the coating, and decreases the wear resistance. It can develop into a big problem.

As the surface treatment agent, a conventionally used surface treatment agent can be used, but a surface treatment agent capable of maintaining the insulating properties of the filler is preferable. For example, titanate coupling agents, aluminum coupling agents, zircoaluminate coupling agents, higher fatty acids, etc., or mixed treatments of these with silane coupling agents, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Silicone, aluminum stearate, or the like, or a mixture thereof is more preferable from the viewpoint of filler dispersibility and image drift prevention. The treatment with the silane coupling agent has a strong influence on the image flow, but the influence may be suppressed by performing a mixing treatment of the surface treatment agent and the silane coupling agent. The surface treatment amount varies depending on the average primary particle size of the filler used, but is preferably 3 to 30% by weight, and more preferably 5 to 20% by weight. If the surface treatment amount is less than this, the filler dispersion effect cannot be obtained, and if it is too much, the residual potential is significantly increased. These filler materials may be used alone or in combination of two or more.

<About other additives>
Furthermore, the crosslinkable charge transport layer coating liquid of the present invention may contain additives such as various plasticizers (for the purpose of stress relaxation and adhesion improvement), leveling agents, and low molecular charge transport materials having no radical reactivity. Can be contained. As these additives, known additives can be used, and as plasticizers, those used in general resins such as dibutyl phthalate and dioctyl phthalate can be used, and the amount used is the total solid content of the coating liquid. It is suppressed to 20 parts by weight or less, preferably 10 parts by weight or less with respect to 100 parts by weight. Further, as the leveling agent, silicone oils such as dimethyl silicone oil and methylphenyl silicone oil, polymers or oligomers having a perfluoroalkyl group in the side chain can be used, and the amount used is 100 total solids of the coating liquid. 3 parts by weight or less is appropriate with respect to parts by weight.

<About film production method>
The crosslinkable charge transport layer of the present invention is formed by applying and curing a coating liquid containing the following three components on the charge transport layer.
First component: a copolymer composed of two or more repeating units, and containing at least one cyclic structure in at least one repeating unit of the two or more repeating units;
Second component: radical polymerizable monomer having no charge transport structure and / or radical polymerizable oligomer having no charge transport structure,
Third component: at least one of radically polymerizable compounds having a charge transporting structure.
When the radically polymerizable monomer or oligomer is a liquid, the coating liquid used for coating can be applied by dissolving other components in the liquid. However, if necessary, it is diluted with a solvent and applied. . The solvent used here is not particularly limited as long as it is usually used. For example, alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, esters such as ethyl acetate and butyl acetate, ethers such as tetrahydrofuran, dioxane and propyl ether, dichloromethane And halogen series such as dichloroethane, trichloroethane and chlorobenzene, aromatic series such as benzene, toluene and xylene, and cellosolv series such as methyl cellosolve, ethyl cellosolve and cellosolve acetate. These solvents may be used alone or in combination of two or more.

The coating method used for forming the cross-linked charge transport layer is not particularly limited as long as it is a commonly used coating method. A coating method may be appropriately selected depending on the viscosity of the coating liquid, the desired thickness of the cross-linked charge transport layer, and the like. Examples include dip coating, spray coating, bead coating, ring coating, and the like.
In this invention, after apply | coating this coating liquid, the bridge | crosslinking type charge transport layer is hardened by giving energy from the outside. As the external energy used at this time, it is possible to use thermal energy, light energy, energy using ionizing radiation, but when ionizing radiation is used, the energy penetration depth and energy intensity For this reason, since there is a concern about deterioration of electrophotographic characteristics accompanying deterioration of the constituent material of the electrophotographic photosensitive member, it is preferable to cure using thermal energy and light energy. In addition, since curing using light energy can be expected to reduce the amount of solvent used during production, reduce energy required for crosslinking, and further increase the strength of the crosslinked film, it is more preferable to use light energy and effectively Any two of the above means may be used in combination for crosslinking.

  As the thermal energy, air, nitrogen and other gases, steam, various heat media, infrared rays, and electromagnetic waves can be used, and heating is performed from the coated surface side or the support side. The heating temperature is preferably 100 ° C. or higher and 170 ° C. or lower. When the temperature is lower than 100 ° C., the reaction rate is slow, so that productivity is lowered and unreacted material remains in the film. On the other hand, when the treatment is performed at a temperature higher than 170 ° C., the shrinkage of the film due to the cross-linking is increased, and the skin-like defects and cracks may be generated on the surface, or peeling may occur at the interface with the adjacent layer. Further, when the volatile component in the photosensitive layer is sprayed to the outside, it is not preferable because desired electrical characteristics may not be obtained. When using a resin having a large shrinkage due to crosslinking, it is also effective to complete the crosslinking at a high temperature of 100 ° C. or higher after preliminary crosslinking at a low temperature of less than 100 ° C.

As the light energy, a light source such as an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc metal halide lamp or the like may be used. It is preferable to select in consideration of absorption characteristics of an oligomer, a radically polymerizable compound having a charge transporting structure (preferably monofunctional), and a photopolymerization initiator used in combination. In general, the light emission illuminance of the light source used is preferably 50 to 2000 mW / cm ^{2 based on} a wavelength of 365 nm. Moreover, when the illuminance measurement in the vicinity of the maximum emission wavelength is possible, it is more preferable to expose in the illuminance range. When the illuminance is low, the time required for curing increases, which is not preferable from the viewpoint of productivity. On the other hand, when the illuminance is high, curing shrinkage is likely to occur, and the surface may have a skin-like defect or crack, or may peel at the interface with the adjacent layer.

  Ionizing radiation is radiation that can ionize a substance. Examples include direct ionizing radiation represented by alpha rays and electron beams, and indirect ionizing radiation represented by X rays and neutron rays. It is done. The ionizing radiation that can be used in the present invention is not particularly limited as long as it is generally used, but in view of the influence on the human body, an electron beam is preferable. As an electron beam irradiation device, when using a device using various electron beam accelerators such as a cockroft Walton type, a bandegraph type, a resonant transformer type, an insulated core transformer type, a linear type, a dynamitron type, a high frequency type, etc. Good. The irradiation amount of the electron beam may be appropriately determined according to the material to be used and the thickness of the cross-linked charge transport layer, but it is usually preferable to irradiate electrons having energy of 100 to 1000 keV, preferably 100 to 3000 keV, about 0.1 to 30 Mrad. . When the irradiation amount is less than 0.1 Mrad, the electron beam cannot reach the inside of the cross-linked charge transport layer, and there is a possibility that poor curing of the deep layer may occur. On the other hand, if the irradiation amount exceeds 30 Mrad, the electron beam may reach the charge transport layer or the charge generation layer described above, which may affect the constituent materials of each layer.

During UV irradiation or ionizing radiation irradiation, the temperature of the photoreceptor cross-linked charge transport layer rises due to the influence of heat rays generated from the light source. If the photoreceptor surface temperature rises too much, cure shrinkage of the crosslinkable charge transport layer is likely to occur, and low molecular components contained in the adjacent layer migrate to the crosslinkable charge transport layer, which may cause curing inhibition. In addition, the electrical characteristics as an electrophotographic photosensitive member are not preferable. Therefore, the photoreceptor surface temperature during UV irradiation is 100 ° C. or less, preferably 80 ° C. or less. As a cooling method, it is possible to use a cooling agent sealed inside the photoconductor, cooling with gas or liquid inside the photoconductor, or the like.
You may post-heat with respect to the bridge | crosslinking type charge transport layer after hardening as needed. For example, in the case where a large amount of residual solvent remains in the film, it may cause a decrease in electrical characteristics or deterioration with time. Therefore, it is preferable to volatilize the residual solvent by post-heating.

The thickness of the cross-linked charge transport layer is preferably 1 to 15 μm, more preferably 3 to 10 μm from the viewpoint of protecting the photosensitive layer. If the cross-linked charge transport layer is thin, not only will it not be possible to protect the photosensitive layer from mechanical wear due to the contact member to the photoreceptor or proximity discharge by a charger, etc., but it will be difficult to level during film formation. The film surface may be distorted. On the other hand, when the crosslinkable charge transport layer is thick, the entire photoreceptor layer becomes thick, and the reproducibility of the image due to the diffusion of charges is not preferable. However, if the thickness of the cross-linked charge transport layer is greater than the thickness of the charge transport layer, the tendency of the bright portion potential to increase is unfavorable. In the present invention, when the thickness of the charge transport layer is T1 (μm) and the thickness of the cross-linkable charge transport layer is T2 (μm), by satisfying the relationship of the following formula (4), the influences thereof are reduced. Since it can suppress, it is more preferable.
T1> T2 × 2 Formula (4)

<About adhesive layer>
For the purpose of preventing delamination due to poor adhesion between the crosslinkable charge transport layer / charge transport layer, an adhesive layer may be provided between both layers as necessary.
As the adhesive layer, the radical polymerizable monomer may be used, or a non-crosslinked polymer compound may be used. Non-crosslinked polymer compounds include polyamide, polyurethane, epoxy resin, polyketone, polycarbonate, silicone resin, acrylic resin, polyvinyl butyral, polyvinyl formal, polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, polyacrylamide, and polyvinyl benzal. , Polyester, phenoxy resin, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyphenylene oxide, polyvinyl pyridine, cellulose resin, casein, polyvinyl alcohol, polyvinyl pyrrolidone, and the like, but are not limited thereto. In addition, the radical polymerizable monomer and the non-crosslinked polymer compound may be used either alone or as a mixture of two or more. Furthermore, a radical polymerizable monomer and a non-crosslinked polymer compound may be used in combination as long as sufficient adhesiveness is obtained. Of course, the charge transport materials described in the present specification may be used or used in combination. Moreover, if it aims at improving adhesiveness, you may use an additive suitably.

  The adhesive layer is formed by applying a coating solution prepared by dissolving or dispersing a compound formulated in a prescribed formulation in a solvent such as tetrahydrofuran, dioxane, dichloroethane, or cyclohexane by dip coating, spray coating, bead coating, or ring coating. it can. The thickness of the adhesive layer is suitably about 0.1 to 5 μm, preferably 0.1 to 3 μm is most suitable.

<About the undercoat layer>
In the photoreceptor of the present invention, an undercoat layer can be provided between the conductive support and the charge generation layer. In general, the undercoat layer is mainly composed of a resin. However, considering that the charge generation layer is applied with a solvent on these resins, the resin is a resin having a high solvent resistance with respect to a general organic solvent. Is desirable. Examples of such resins include water-soluble resins such as polyvinyl alcohol, casein, and sodium polyacrylate, alcohol-soluble resins such as copolymer nylon and methoxymethylated nylon, polyurethane, melamine resin, phenol resin, alkyd-melamine resin, and epoxy. Examples thereof include a curable resin that forms a three-dimensional network structure such as a resin. Further, a metal oxide fine powder pigment exemplified by titanium oxide, silica, alumina, zirconium oxide, tin oxide, indium oxide and the like may be added to the undercoat layer in order to prevent moire and reduce residual potential.

These undercoat layers can be formed using an appropriate solvent and a coating method like the above-mentioned photosensitive layer. Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, or the like can be used as the undercoat layer of the present invention. In addition, in the undercoat layer of the present invention, Al ₂ O ₃ is provided by anodic oxidation, organic substances such as polyparaxylylene (parylene), SiO ₂ , SnO ₂ , TiO ₂ , ITO, CeO ₂ A material provided with an inorganic material such as a vacuum thin film can also be used favorably. In addition, known ones can be used.
The thickness of the undercoat layer is suitably from 0 to 5 μm.

<About blocking layer>
It is also possible to further provide a blocking layer between the conductive support and the undercoat layer or between the undercoat layer and the charge generation layer. The blocking layer is added to suppress the injection of holes from the conductive support, and the main purpose is to suppress the soiling. In the blocking layer, a binder resin is generally used as a main component. Examples of these resins include polyamide, alcohol-soluble polyamide (soluble nylon), water-soluble polyvinyl butyral, polyvinyl butyral, and polyvinyl alcohol. As a method for forming the blocking layer, the above-described method and a known coating method are employed. In addition, 0.05-2 micrometers is suitable for the thickness of a blocking layer. By adopting the two-layer configuration of the blocking layer and the undercoat layer, the background stain suppression effect is dramatically increased, but the influence of the residual potential increase tends to increase. Therefore, it is necessary to determine the composition and thickness of the blocking layer and the undercoat layer with sufficient consideration.

<< Regarding Configuration of Image Forming Apparatus >>
Next, the image forming apparatus of the present invention will be described in detail with reference to the drawings.
The image forming apparatus of the present invention uses the electrophotographic photosensitive member having the cross-linked charge transport layer of the present invention. ) And a means for fixing and cleaning the surface of the photoreceptor, if necessary. In some cases, an image forming apparatus that directly transfers an electrostatic latent image to a transfer body and develops the image forming apparatus does not necessarily include the above-described means disposed on the photoreceptor.

FIG. 2 is a schematic diagram illustrating an example of an image forming apparatus. A charging charger (3) is used as a means for charging the photoconductor on average. As the charging means, a corotron device, a scorotron device, a solid discharge element, a needle electrode device, a roller charging device, a conductive brush device, or the like is used, and a known system can be used.
Next, the image exposure unit (5) is used to form an electrostatic latent image on the uniformly charged photoreceptor (1). As the light source, all luminescent materials such as a fluorescent lamp, a tungsten lamp, a halogen lamp, a mercury lamp, a sodium lamp, a light emitting diode (LED), a semiconductor laser (LD), and an electroluminescence (EL) can be used. Various types of filters such as a sharp cut filter, a band pass filter, a near infrared cut filter, a dichroic filter, an interference filter, and a color temperature conversion filter can be used to irradiate only light in a desired wavelength range.

Next, the developing unit (6) is used to visualize the electrostatic latent image formed on the photoreceptor (1). Development methods include a one-component development method using a dry toner, a two-component development method, and a wet development method using a wet toner. When the photosensitive member is positively (negatively) charged and image exposure is performed, a positive (negative) electrostatic latent image is formed on the surface of the photosensitive member. A positive image can be obtained by developing this with negative (positive) toner (electrodetection fine particles), and a negative image can be obtained by developing with positive (negative) toner.
Next, a transfer charger (10) is used to transfer the toner image visualized on the photoconductor onto the transfer body (9). In addition, a pre-transfer charger (7) may be used for better transfer. As these transfer means, a transfer charger, an electrostatic transfer method using a bias roller, a mechanical transfer method such as an adhesive transfer method and a pressure transfer method, and a magnetic transfer method can be used. As the electrostatic transfer method, the charging means can be used.
Next, a separation charger (11) and a separation claw (12) are used as means for separating the transfer body (9) from the photoreceptor (1). As other separation means, electrostatic adsorption induction separation, side end belt separation, tip grip conveyance, curvature separation, and the like are used. As the separation charger (11), the charging means can be used.

Next, a fur brush (14) and a cleaning blade (15) are used to clean the toner remaining on the photoreceptor after transfer. Further, a pre-cleaning charger (13) may be used in order to perform cleaning more efficiently. Other cleaning means include a web method, a magnet brush method, and the like, but each may be used alone or in combination. Next, a neutralizing unit is used for the purpose of removing the latent image on the photoreceptor as required. As the charge removal means, a charge removal lamp (2) and a charge removal charger are used, and the exposure light source and the charging means can be used respectively. In FIG. 2, 8 is a registration roller.
In addition, known means can be used for reading, feeding, fixing, and discharging the document that are not close to the photosensitive member.
The image forming apparatus of the present invention may be configured such that a plurality of image forming elements each including at least a charging unit, an exposure unit, a developing unit, a transfer unit, and an electrophotographic photosensitive member are arranged.

The present invention also relates to an image forming method and an image forming apparatus process cartridge using the electrophotographic photoreceptor according to the present invention for such image forming means.
The image forming means may be fixedly incorporated in a copying apparatus, facsimile, or printer, but may be incorporated in these apparatuses in the form of a process cartridge and detachable. An example of the process cartridge is shown in FIG.
The process cartridge for the image forming apparatus includes a photoreceptor (101), and in addition, a charging unit (102), a developing unit (104), a transfer unit (106), a cleaning unit (107), and a discharging unit (not shown). ), And an apparatus (part) that can be attached to and detached from the image forming apparatus main body.

  Referring to the image forming method using the apparatus illustrated in FIG. 3, the surface of the photoconductor (101) is exposed by charging by the charging means (102) and exposure by the exposure means (103) while rotating in the arrow direction. An electrostatic latent image corresponding to the image is formed, and the electrostatic latent image is developed with toner by the developing means (104). The toner development is transferred to the transfer body (105) by the transfer means (106), and printed. Be out. Next, the surface of the photoconductor after the image transfer is cleaned by a cleaning unit (107), and further neutralized by a neutralizing unit (not shown), and the above operation is repeated again.

Next, an image forming apparatus in which a plurality of image forming elements comprising the charging means, the exposure means, the developing means, and the electrophotographic photosensitive member of the present invention are arranged will be described.
In the case of a color electrophotographic image forming apparatus in which an image forming element is configured as a unit in which an electrophotographic photosensitive member and at least a charging member, a developing member, and a cleaning member are disposed around the electrophotographic photosensitive member, The number of image forming elements corresponding to the number of colors is mounted, and each image forming element can be fixed to the image forming apparatus or can be individually replaced.

FIG. 4 is a schematic diagram for explaining an electrophotographic image forming apparatus (generally called a tandem full-color electrophotographic image forming apparatus) having a plurality of image forming elements. Modifications also belong to the category of the present invention.
In FIG. 4, reference numeral (1C, 1M, 1Y, 1K) denotes a drum-shaped photoconductor. A charging member (2C, 2M, 2Y, 2K), a developing member (4C, 4M, 4Y, 4K), and a cleaning member (5C, 5M, 5Y, 5K) are arranged in this order. The charging members (2C, 2M, 2Y, 2K) are charging members that constitute a charging device for uniformly charging the surface of the photoreceptor.

  Laser light (3C, 3M, 3Y, 3K) from an exposure member (not shown) is irradiated between the charging member (2C, 2M, 2Y, 2K) and the developing member (4C, 4M, 4Y, 4K), An electrostatic latent image is formed on the photoreceptor (1C, 1M, 1Y, 1K). Then, four image forming elements (6C, 6M, 6Y, 6K) centering on such a photoreceptor (1C, 1M, 1Y, 1K) are along a transfer conveyance belt (10) which is a transfer material conveyance means. Are juxtaposed. The transfer / conveying belt (10) is provided between the developing member (4C, 4M, 4Y, 4K) and the cleaning member (5C, 5M, 5Y, 5K) of each image forming unit (6C, 6M, 6Y, 6K). 1C, 1M, 1Y, 1K), and a transfer brush (11C, 11M, 11Y, 11K) for applying a transfer bias to the back surface (back surface) of the transfer conveyance belt (10) that contacts the back side of the photoconductor. Is arranged. Each image forming element (6C, 6M, 6Y, 6K) is different in the color of the toner inside the developing device, and the others are the same in configuration.

  In the color electrophotographic image forming apparatus having the configuration shown in FIG. 4, the image forming operation is performed as follows. First, in each image forming element (6C, 6M, 6Y, 6K), the charging member (2C, 2M, 2Y) in which the photoconductor (1C, 1M, 1Y, 1K) rotates in the direction of the arrow (direction along with the photoconductor). , 2K), and then an electrostatic latent image corresponding to each color image to be created by laser light (3C, 3M, 3Y, 3K) by an exposure unit (not shown) disposed inside the photoconductor. It is formed.

Next, the latent image is developed by the developing members (4C, 4M, 4Y, 4K) to form a toner image. The developing members (4C, 4M, 4Y, 4K) are developing members that perform development with toners of C (cyan), M (magenta), Y (yellow), and K (black), respectively. 1M, 1Y, and 1K) are overlaid on the transfer paper.
The transfer paper (7) is fed out from the tray by the paper feed roller (8), temporarily stopped by the pair of registration rollers (9), and then transferred to the transfer conveyance belt (10) in synchronization with the image formation on the photosensitive member. Sent. The transfer paper (7) held on the transfer / conveying belt (10) is conveyed, and the toner images of the respective colors are transferred at the contact positions (transfer portions) with the respective photoreceptors (1C, 1M, 1Y, 1K). It is.

The toner image on the photosensitive member is transferred onto the transfer paper (by the electric field formed by the potential difference between the transfer bias applied to the transfer brush (11C, 11M, 11Y, 11K) and the photosensitive member (1C, 1M, 1Y, 1K). 7) Transferred on top. Then, the recording paper (7) on which the toner images of four colors are superimposed through the four transfer portions is conveyed to the fixing device (12), where the toner is fixed, and is discharged to a paper discharge portion (not shown). Further, the residual toner remaining on the respective photoconductors (1C, 1M, 1Y, 1K) without being transferred by the transfer unit is collected by the cleaning device (5C, 5M, 5Y, 5K). In the illustrated example, the image forming elements are arranged in the order of C (cyan), M (magenta), Y (yellow), and K (black) from the upstream side to the downstream side in the transfer paper conveyance direction. However, it is not limited to this order, and the color order is arbitrarily set.
Further, when a black-only document is created, it is particularly effective to use the present invention to provide a mechanism for stopping the image forming elements (6C, 6M, 6Y) other than black. Further, in FIG. 4, although the charging member is in contact with the photosensitive member, by providing an appropriate gap (about 10 to 200 μm) between them, the wear amount of both can be reduced and the toner film on the charging member can be reduced. It can be used satisfactorily with less ming.

  Since the electrophotographic photosensitive member of the present invention is excellent in releasability, the burden on cleaning is small. For this reason, the life of the cleaning unit is extended. It also contributes to the downsizing of the cleaning unit. Furthermore, since the toner transfer rate is high, waste toner can be reduced and the toner can be used effectively.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to a following example. Parts and% are based on weight.
First, a synthesis example of a charge generation material (titanyl phthalocyanine crystal) will be described.

(Synthesis Example 1)
(Synthesis of titanyl phthalocyanine crystal)
First, a method for synthesizing the titanyl phthalocyanine crystal used in the present invention will be described. The synthesis was in accordance with Japanese Patent Application Laid-Open No. 2004-83859. That is, 292 parts of 1,3-diiminoisoindoline and 1800 parts of sulfolane are mixed, and 204 parts of titanium tetrabutoxide are added dropwise under a nitrogen stream. After completion of the dropwise addition, the temperature was gradually raised to 180 ° C., and the reaction was carried out by stirring for 5 hours while maintaining the reaction temperature between 170 ° C. and 180 ° C. After the reaction is complete, the mixture is allowed to cool, and then the precipitate is filtered, washed with chloroform until the powder turns blue, then washed several times with methanol, then washed several times with hot water at 80 ° C. and dried. Crude titanyl phthalocyanine was obtained. Crude titanyl phthalocyanine is dissolved in 20 times the amount of concentrated sulfuric acid, added dropwise to 100 times the amount of ice water with stirring, the precipitated crystals are filtered, and then ion-exchanged water (pH: 7.) until the washing solution becomes neutral. 0, specific conductivity: 1.0 μS / cm) Repeated washing with water (pH value of ion-exchanged water after washing was 6.8, specific conductivity was 2.6 μS / cm), wet of titanyl phthalocyanine pigment A cake (water paste) was obtained.

40 parts of this wet cake (water paste) thus obtained was put into 200 parts of tetrahydrofuran and stirred vigorously (2000 rpm) with a homomixer (Kennis, MARKIIf model) at room temperature, and the dark blue color of the paste turned pale blue. When changed (20 minutes after the start of stirring), stirring was stopped and filtration under reduced pressure was immediately performed. The crystals obtained on the filtration device were washed with tetrahydrofuran to obtain a wet cake of pigment. This was dried under reduced pressure (5 mmHg) at 70 ° C. for 2 days to obtain 8.5 parts of titanyl phthalocyanine crystals. The solid content concentration of the wet cake was 15% by mass. The crystal conversion solvent was used in a mass ratio of 33 times that of the wet cake. In addition, the halogen-containing compound is not used for the raw material of the synthesis example 1. When the obtained titanyl phthalocyanine powder was subjected to X-ray diffraction spectrum measurement under the following conditions, the Bragg angle 2θ with respect to CuKα ray (wavelength 1.542１．５) was 27.2 ± 0.2 °, and the maximum peak and the minimum angle 7.3. It has a peak at ± 0.2 °, and further has major peaks at 9.4 ± 0.2 °, 9.6 ± 0.2 °, 24.0 ± 0.2 °, and 7.3 A titanyl phthalocyanine powder having no peak between the peak at 0 ° and the peak at 9.4 ° and further having no peak at 26.3 ° was obtained. The result is shown in FIG.
<X-ray diffraction spectrum measurement conditions>
X-ray tube: Cu
Voltage: 50kV
Current: 30mA
Scanning speed: 2 ° / min Scanning range: 3 ° -40 °
Time constant: 2 seconds

Charge generation layer coating solution Using a PSZ ball having a diameter of 0.5 mm in a commercially available bead mill disperser, a 2-butanone solution in which polyvinyl butyral was dissolved and a titanyl phthalocyanine crystal were introduced, and the rotor rotation speed was 1200 r. p. m. For 30 minutes to prepare a charge generation layer coating solution.
Titanylphthalocyanine crystal 15 parts Polyvinyl butyral (manufactured by Sekisui Chemical: BX-1) 10 parts 2-butanone 280 parts

(Synthesis Example 2)
Next, a synthesis example of a compound having a monofunctional charge transporting structure used for a cross-linked charge transport layer in a photoreceptor preparation example described later will be described.
(Synthesis example of a compound having a monofunctional charge transporting structure)
The compound having a monofunctional charge transport structure in the present invention is synthesized, for example, by the method described in Japanese Patent No. 3164426. An example of this is shown below.
(1) Synthesis of hydroxy group-substituted triarylamine compound (following formula B) 113.85 parts (0.3 mol) of methoxy group substituted triarylamine compound (following formula A) and 138 parts (0.92 mol) of sodium iodide To this, 240 parts of sulfolane was added and heated to 60 ° C. in a nitrogen stream. In this liquid, 99 parts (0.91 mol) of trimethylchlorosilane was added dropwise over 1 hour and stirred at a temperature of about 60 ° C. for 4 and a half hours to complete the reaction.
About 1500 parts of toluene was added to the reaction solution, cooled to room temperature, and washed repeatedly with water and an aqueous sodium carbonate solution.
Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene: ethyl acetate = 20: 1).
Cyclohexane was added to the obtained pale yellow oil to precipitate crystals.
In this way, 88.1 parts (yield = 80.4%) of white crystals of the following formula B were obtained.
Melting point: 64.0-66.0 ° C

(2) Triarylamino group-substituted acrylate compound (Exemplary Compound No. 7)
82.9 parts (0.227 mol) of the hydroxy group-substituted triarylamine compound (formula B) obtained in (1) above is dissolved in 400 ml of tetrahydrofuran, and an aqueous sodium hydroxide solution (NaOH: 12.4 parts) in a nitrogen stream. Water: 100 ml) was added dropwise. The solution was cooled to 5 ° C., and 25.2 parts (0.272 mol) of acrylic acid chloride was added dropwise over 40 minutes. Then, it stirred at 5 degreeC for 3 hours, and reaction was terminated. The reaction solution was poured into water and extracted with toluene. This extract was repeatedly washed with an aqueous sodium bicarbonate solution and water. Thereafter, the solvent was removed from the toluene solution, and purification was performed by column chromatography (adsorption medium: silica gel, developing solvent: toluene). N-Hexane was added to the obtained colorless oil to precipitate crystals. In this way, Exemplified Compound No. As a result, 80.73 parts of white crystals (yield = 84.8%) were obtained.
Melting point: 117.5-119.0 ° C

[Examples 1 to 63, Comparative Examples 1 to 5]
An undercoat layer coating solution, a charge generation layer coating solution, a charge transport layer coating solution, and a crosslinkable charge transport layer coating solution are sequentially applied to an aluminum cylinder having a diameter of 100 mm as a conductive support. The substrate was dried to form an undercoat layer of about 3.5 μm, a charge generation layer of about 0.2 μm, a charge transport layer of about 23 μm, and a cross-linked charge transport layer of about 5 μm to produce a laminated photoreceptor. After the coating of each layer, touch drying was performed, and then the undercoat layer was dried at 130 ° C., the charge generation layer was 95 ° C., and the charge transport layer was dried at 120 ° C. for 20 minutes.
The crosslinkable charge transport layer is formed by applying a crosslinkable charge transport layer coating solution onto a laminated photoreceptor composed of the conductive support / undercoat layer / charge generation layer / charge transport layer and then applying a UV lamp (bulb type H bulb). ) (Manufactured by Fusion UV Systems Co., Ltd.) was used for crosslinking by light irradiation under the conditions of a lamp output of 200 W / cm, illuminance: 450 mW / cm ² , and irradiation time: 30 seconds. Thereafter, drying was performed at 130 ° C. for 20 minutes to obtain an electrophotographic photosensitive member comprising a conductive support / undercoat layer / charge generation layer / charge transport layer / crosslinked charge transport layer.

(Coating liquid for undercoat layer)
Titanium oxide (CR-EL, average primary particle size: about 0.25 μm, manufactured by Ishihara Sangyo Co., Ltd.):
50 parts alkyd resin (Beckolite M6401-50, solid content: 50%, manufactured by Dainippon Ink & Chemicals, Inc.): 14 parts melamine resin (L-145-60, solid content: 60%, Dainippon Ink & Chemicals, Inc.) Manufactured by :) 8 parts 2-butanone: 70 parts

(Charge transport layer coating solution)
Bisphenol Z polycarbonate 10 parts (Panlite TS-2050, manufactured by Teijin Chemicals)
Charge transport material 7 parts Tetrahydrofuran 68 parts 1% silicone oil in tetrahydrofuran 0.2 parts (KF50-1CS, manufactured by Shin-Etsu Chemical Co., Ltd.)
The charge transport material was selected from compounds having the following structural formula. Table 7 shows the charge transport materials used.

[Coating liquid for cross-linked charge transport layer]
First component 0.1 part Second component 9.9 part Third component 20 part Photopolymerization initiator 2 parts (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Tetrahydrofuran 200 parts The first component, the second component, and the third component were selected from the following compounds. Table 7 shows the materials used.

First component No. 1 to 37 were prepared as follows.
First component material
Methyl methacrylate (Light Ester M, Kyoeisha Chemical) ... CPM-1
2-Ethylhexyl acrylate (Nippon Catalyst) ... CPM-2
Butyl acrylate (Nippon Catalyst) CPM-3
Methacrylic acid (light ester A) CPM-4

  Note that adamantyl acrylate was synthesized according to Japanese Patent Application Laid-Open No. 2001-106650. That is, a 2000 ml capacity separable flask equipped with a stirrer, a thermometer, a Dean-Stark water separator, a Dimroth cooler, an air introduction pipe and a separation valve at the bottom containing 0.05% by weight of sodium chloride 1,3 -86.4 g (513 mmol) of adamantanediol, 400 ml of toluene, 400 ml of n-octane, 108 g (1500 mmol) of acrylic acid, 1.23 g of concentrated sulfuric acid, and 0.37 g of p-methoxyphenol were charged. The reaction was carried out for 5 hours under reflux (112 ° C.) while blowing a small amount of air. During this time, by-product water was removed using a Dean-Stark water separator. The reaction solution was cooled to room temperature, and insoluble matters were filtered off. After adding 840 g of 5 wt% sodium hydroxide aqueous solution and mixing and separating, the organic phase was washed 6 times with 400 ml of water. The organic phase was concentrated under reduced pressure, filtered and dried to obtain 83.8 g of adamantyl acrylate as a white powder.

Copolymer Preparation Example <First Component No. Production of 1 to 24 and 29 to 34>
10.0 g (0.045 mol) of isobornyl methacrylate, 0.242 g (0.003 mol) of methyl methacrylate, 0.518 g (0.003 mol) of 2-ethylhexyl acrylate, 0.484 g (0.006 mol) of methacrylic acid, and propylene glycol Monomethyl ether 10.0g was mixed. The above-mentioned formulation solution was placed in a four-diameter flask and bubbled with nitrogen at room temperature for 30 minutes. The mixture was gradually heated to 105 ° C. and reacted for 3 hours. Thereafter, a mixture of 0.484 g of tertiary butyl peroxy-2-ethylhexate and 15.0 g of propylene glycol monomethyl ether was dropped into the above mixture and reacted for 30 minutes to obtain a copolymer having a weight average molecular weight of 7500. It was. This is the first component No. 3.
First component No. 3 under the same reaction conditions as in the preparation of Copolymers of 1-2, 4-24, and 29-34 were obtained. Table 3 shows the materials and molar ratios used in this case, and Table 6 shows the amounts charged and the weight average molecular weight. “none” indicates that it is not used.

<First Component No. Production of 25-28>
First component No. 3 under the same reaction conditions as in the preparation of A copolymer of 25 to 28 was obtained. Table 3 shows the materials and molar ratios used in this case, and Table 6 shows the amounts charged and the weight average molecular weight. “none” indicates that it is not used.
In Table 3, the first component No. CP1 / 2, CP2 / 3, CP1 / 3, CP1 / 2/3 for 25-28 are a plurality of species selected from CP-1, CP-2 and CP-3 which are compounds having a cyclic structure. Indicates that it was used.
In Tables 4 and 5, the first component No. The prescription and charge amount of the material 1 of 25-28 are shown.

(Synthesis of unsaturated double bond-containing copolymer)
<First Component No. Production of 35>
17.786 g (0.08 mol), methyl methacrylate 0.430 g (0.005 mol) and 2-ethylhexyl acrylate 0.921 g (0.005 mol) of the radical polymerizable compound isobornyl methacrylate (CP-1) described in Table 3 ), 0.861 g (0.01 mol) of methacrylic acid and 26.601 g of propylene glycol monomethyl ether were mixed. The above-mentioned formulation solution was placed in a four-diameter flask and bubbled with nitrogen at room temperature for 30 minutes. The mixture was gradually heated to 105 ° C. and reacted for 3 hours. Thereafter, a mixed solution of 1.287 g of tertiary butyl peroxy-2-ethyl hexaate and 39.902 g of propylene glycol monomethyl ether was added dropwise to the above mixed solution and reacted for 30 minutes.
To the reaction solution, 0.013 g of propylene glycol monomethyl ether solution containing 0.201 g of tetrabutylammonium bromide and 0.08 g of hydroquinone was added, and 3.46 g of glycidyl methacrylate and 0.005 g of propylene glycol monomethyl ether were bubbled with air. Was added dropwise over about 1 hour, followed by reaction for 5 hours. 35 was obtained.

<First Component No. Production of 36>
First component No. No. 35 except that 16.502 g (0.08 mol) of adamantyl acrylate (CP-2) was used instead of 17.786 g of 35 isobornyl methacrylate (CP-1). As in 35, an unsaturated double bond-containing copolymer was synthesized.
<First Component No. Production of 37>
First component No. No. 35 except that 12.336 g (0.08 mol) of cyclohexyl acrylate (CP-3) was used instead of 17.786 g of 35 isobornyl methacrylate (CP-1). As in 35, an unsaturated double bond-containing copolymer was synthesized.

Second component, trimethylolpropane triacrylate (KAYARAD TMPTA, manufactured by Nippon Kayaku) (AM-1)
Molecular weight: 296, number of functional groups: trifunctional, molecular weight / number of functional groups = 99
・ Pentaerythritol triacrylate ・ ・ ・ AM-2
(Daicel Cytec Co., Ltd., PETIA)
・ 1,6-hexanediol diacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) (AM-3)
Molecular weight: 226, number of functional groups: bifunctional, molecular weight / number of functional groups = 113
-Dipentaerythritol caprolactone-modified hexaacrylate (KAYARAD DPCA-120, manufactured by Nippon Kayaku Co., Ltd.) (AM-4)
Molecular weight: 1947, number of functional groups: 6 functions, molecular weight / number of functional groups = 325

(Polymerization initiator)
1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals) ... I-184

Third component

Filler Alumina (Average primary particle size: 0.3 μm, Sumiko Random AA03, manufactured by Sumitomo Chemical)
... F-1
Silica Hydrophobized silica powder (trade name: KMPX-100, average particle size 0.1 μm, manufactured by Shin-Etsu Chemical Co., Ltd.)
... F-2
Particles made of an acrylic-modified polyorganosiloxane compound (Charine R-170S, manufactured by Nissin Chemical Industry Co., Ltd.) F-3

Filler The crosslinking type charge transport layer coating solution in the case of containing the filler is as follows.
1st component 0.1 part 2nd component 9.9 part 3rd component 20 part Filler 4 parts Photopolymerization initiator 2 parts (1-hydroxy-cyclohexyl-phenyl-ketone (Irgacure 184, manufactured by Ciba Specialty Chemicals))
Tetrahydrofuran 219 parts

Table 7 shows the formulation of the electrophotographic photoreceptor used in the examples.

Table 8 shows a recipe for the electrophotographic photoreceptor used in the comparative example.

<Real machine test>
Wear amount measurement, transfer rate measurement, and image quality evaluation were performed by the following methods.
In addition, in the evaluation of Examples 1 to 60 and Comparative Examples 1 to 5, a Ricoh imago Neo Neo 753 remodeling machine having one image forming element and having no lubricant application mechanism was used.
Paper running by actual machine is performed by attaching the electrophotographic photosensitive member to an electrophotographic process cartridge and using a modified Rigoh imagio Neo753 machine, with a maximum of 500,000 actual machine paper feeding tests (A4, MyPaper made by NBS Ricoh, Charging potential at start-700V) was carried out.
In Examples 61 to 63, the lubricant was removed from the black cartridge of Ricoh's imgio MPC 7500 in which a plurality of image forming elements were arranged, the electrophotographic photosensitive member was mounted on the black cartridge, and a paper passing test was performed in the same manner as described above. .
Note that the paper-running test was performed at the Japan Imaging Society test chart no. An 8-6% chart was used.

(Transfer rate measurement)
The transfer rate measurement was calculated using the following formula.
Transfer rate = 1- <transfer residual toner rate>
= 1-<(transfer residual toner M / A) / (toner M / A before transfer)>
The developed chart on the photosensitive member is transferred, and the apparatus is stopped when the transfer paper is on the conveying belt. Paying attention to the black solid portion of the chart, the transfer residual toner amount of the black solid portion on the photosensitive member is peeled off with an adhesive tape to obtain the residual toner amount on the photosensitive member. At this time, a coefficient is calculated from a plot of the residual toner ID (image density, image density) and the toner amount, and the residual toner M / A (weight per unit area of the toner adhered to the photoconductor: mg / mm) from the residual toner ID. cm ² ) was calculated. The toner before transfer was calculated by measuring the amount of toner before transfer on the M / A photoconductor. As the transfer rate evaluation chart, a solid image with an image area of 2 cm ² was used.

(Abrasion amount measurement)
The photoreceptor was taken out after the running of 500,000 sheets, and the amount of wear was measured from the difference in film thickness of the photoreceptor before and after the running test. For film thickness measurement, an eddy current film thickness meter Fischer scope MMS (manufactured by Fischer) was used.

(Image quality evaluation)
Before running and after running 500,000 copies, the Japan Imaging Society test chart No. 3 was output and the image quality was evaluated. Evaluation was performed according to the following criteria.
(Double-circle): The level by which image quality hardly falls.
○: Level of image quality slightly decreased, but no problem with visual observation △: Level where degradation of image quality can be seen even with visual observation ×: Level with serious problem in image quality

The test results are shown in Tables 9 and 10 below.

In Comparative Examples 1 and 5, foreign matter was confirmed on the photosensitive member after the running of 500,000 sheets. In Comparative Example 2, since the initial image density was very thin, the transfer rate measurement and the running test were not performed.
From the examples, the crosslinkable charge transport layer is composed of two or more repeating units, and is selected from the group consisting of a first component that is a copolymer containing at least one cyclic structure in the repeating units, and a monomer or oligomer. An electrophotography comprising a second component which is a radically polymerizable compound having no one or more types of charge transporting structures and a structural unit derived from a third component which is a radically polymerizable compound having at least one type of charge transporting structures It can be seen that the photoreceptor is excellent in releasability and wear resistance.
By comparing Examples 47 and 48, the electrophotographic photoreceptor of the present invention in which the cyclic structure contained in the first component is composed of carbon-carbon bonds and the number of carbon atoms constituting the cyclic structure is 6 or more is further separated. It turns out that it is excellent in formability.
From Examples 49 to 51, the electrophotographic photosensitive member of the present invention in which the cyclic structure contained in the first component is at least one selected from an adamantane ring, a norbornane ring, and a cyclohexyl ring is excellent in releasability and resistance. Abrasion is also high.
From Examples 52 to 54, the electrophotographic photosensitive member of the present invention in which the copolymerization ratio of the cyclic compound of the copolymer of the first component is 0.3 or more and 0.9 or less exhibits extremely excellent releasability.
From Examples 55 to 57, the electrophotographic photoreceptor of the present invention containing at least one distyrylbenzene derivative as a charge transport material in the charge transport layer is excellent in image quality stability.
From Examples 5 to 8, 13 to 16, and 21 to 24, the electrophotographic photoreceptor of the present invention in which the copolymerization ratio of the cyclic compound of the copolymer of the first component is 0.3 or more and 0.9 or less is high. Transfer rate.
From the results of Examples 1 to 46, the electrophotographic photosensitive member containing a filler in the cross-linked charge transport layer has a high transfer rate, high wear resistance, and hardly produces an abnormal image.
From the above, according to the present invention, both mechanical durability and high releasability can be achieved.

The results obtained by observing the electrophotographic photosensitive member used in Example 3 and Example 55 with SPM (D3100, manufactured by BioScope) are shown in FIGS. The measurement conditions are as follows.
Probe: NCHV-10V
Number of scans: 256
The electrophotographic photosensitive member of the present invention has fine irregularities on the surface as shown in these drawings. This is considered to be due to the occurrence of layer separation because the compatibility of the first component, the second component, and the third component is different. Since the electrophotographic photoreceptor of the present invention has fine irregularities on the surface, it is considered to have excellent releasability. It is thought that both mold release and mechanical durability were realized due to the fine unevenness and the cross-linked structure.

DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Static elimination lamp 3 Charger charger 5 Image exposure part 6 Developing unit 7 Charger before transfer 8 Registration roller 9 Transfer body 10 Transfer charger 11 Separation charger 12 Separation claw 13 Charger before cleaning 14 Fur brush 15 Cleaning blade 31 Conductive support 32 charge generation layer 33 charge transport layer 34 cross-linked charge transport layer 101 photoconductor 102 charging means 103 exposure means 104 developing means 105 transfer body 106 transfer means 107 cleaning means

(In FIG. 4)
1C, 1M, 1Y, 1K Photoconductors 2C, 2M, 2Y, 2K Charging members 3C, 3M, 3Y, 3K Laser beams 4C, 4M, 4Y, 4K Developing members 5C, 5M, 5Y, 5K Cleaning members 6C, 6M, 6Y , 6K image forming element 7 transfer paper 8 paper feed roller 9 registration roller 10 transfer transport belt 11C, 11M, 11Y, 11K transfer brush 12 fixing device

JP 2002-139659 A JP 2001-125286 A JP 2001-324857 A JP 2003-098708 A JP-A-5-181299 Japanese Patent Laid-Open No. 2002-006526 JP 2002-082465 A JP 2000-284514 A JP 2000-284515 A JP 2001-194413 A Japanese Patent No. 3194392 JP 2004-302451 A JP 2005-99688 A JP 2007-178815 A JP 2002-6526 A JP 2008-139824 A JP 2008-233893 A JP 2003-302777 A JP-A-5-216249 JP 2005-55589 A

Claims (7)

In an electrophotographic photosensitive member in which at least a charge generation layer, a charge transport layer, and a cross-linked charge transport layer are sequentially laminated on a conductive support,
An electrophotographic photoreceptor, wherein the cross-linked charge transport layer comprises structural units derived from the following first component, second component and third component.
First component: a copolymer comprising two or more repeating units, wherein at least one repeating unit of the two or more repeating units contains at least one cyclic structure selected from an adamantane ring and a norbornane ring Second component: radical polymerizable monomer having no charge transport structure and / or radical polymerizable oligomer having no charge transport structure Third component: at least one of radical polymerizable compounds having a charge transport structure 2. The electrophotographic photosensitive member according to claim 1, wherein the copolymerization ratio of the cyclic compound of the copolymer of the first component is 0.3 or more and 0.9 or less in terms of molar ratio. The charge transport layer, the electrophotographic photosensitive member according to claim 1 or 2, characterized in that it comprises at least one distyryl benzene derivative represented by the following general formula (1) as a charge transporting substance.
[In the above formula, R _{1 to} R ₃₀ are a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. A substituted aryl group, an unsubstituted aryl group, an alkyl group having 1 to 4 carbon atoms or a benzyl group substituted with an alkoxy group having 1 to 4 carbon atoms may be the same or different. ] Wherein the crosslinked charge transporting layer, at least one of the electrophotographic photosensitive member according to any one of claims 1 to 3, characterized in that it comprises a filler particle. At least charging means, exposure means, developing means, transfer means, and an image forming apparatus comprising comprising an electrophotographic photosensitive member, the electrophotographic photosensitive described electrophotographic photoreceptor is any one of claims 1 to 4 An image forming apparatus characterized by being a body. At least charging means, an exposure means, the imaging element consisting of the developing means, and an electrophotographic photosensitive member is arrayed, the electrophotographic photoreceptor is an electrophotographic photoreceptor according to any one of claims 1 to 4 An image forming apparatus. In the process cartridge for an image forming apparatus in which the electrophotographic photosensitive member is integrated with at least one means selected from a charging unit, an exposing unit, a developing unit, a transferring unit, and a cleaning unit, the electrophotographic photosensitive unit is claimed in claim 1. A process cartridge for an image forming apparatus, which is the electrophotographic photosensitive member according to any one of claims 1 to 4 .