JP4765836B2 - An electrophotographic photosensitive member and an image forming apparatus equipped with the same. - Google Patents

Description

  The present invention relates to an electrophotographic photosensitive member used for a copying machine, a printer, and the like. More specifically, the present invention relates to a sheet-like electrophotographic photosensitive member having good handleability, excellent wear resistance, and good electrical characteristics.

  Electrophotographic technology is widely used in the fields of copiers and various printers because of its immediacy and high quality images. As a photoreceptor which is the core of electrophotographic technology, a photoreceptor using an organic photoconductive material having advantages such as non-pollution, easy film formation, and easy manufacture is used.

  As a photoreceptor using an organic photoconductive material, a so-called dispersion type photoreceptor in which a photoconductive fine powder is dispersed in a binder resin, and a laminate type photoreceptor in which a charge generation layer and a charge transport layer are laminated are known. ing. Multilayered photoreceptors can be obtained by combining highly efficient charge generating substances and charge transporting substances to obtain highly sensitive photoreceptors, having a wide range of material selections and providing highly safe photoreceptors, and photosensitive layers. Can be easily formed by coating, has high productivity, and is advantageous in terms of cost. Therefore, it is the mainstream of photoconductors, and has been developed and put into practical use.

  Among them, an endless belt-like photoreceptor in which a sheet-like photoreceptor is joined at the end is preferred because the property is flexible and the degree of freedom in arranging in the apparatus is large. For reasons such as easy replacement, a photoreceptor in the form of a sheet-like photoreceptor wound around a drum is preferably used (see, for example, Patent Document 1 and Patent Document 2).

  Since the electrophotographic photosensitive member is repeatedly used in an electrophotographic process, that is, a cycle of charging, exposure, development, transfer, cleaning, static elimination, etc., it is deteriorated by various stresses during that time. Such deterioration includes, for example, strong oxidation ozone and NOx generated from a corona charger used as a charger, which causes chemical damage to the photosensitive layer, or a carrier generated by image exposure or static elimination light. There are chemical and electrical degradations such as flowing in the photosensitive layer and decomposition of the photosensitive layer composition by external light. In addition, there are other mechanical degradations such as rubbing of the cleaning blade, magnetic brush, developer, contact with the transfer member or paper, mechanical layer degradation such as abrasion or scratches on the surface of the photosensitive layer, and film peeling. .

  In particular, in an endless belt-like photoconductor, cracks may occur on the surface of the photoconductor due to bending and tension that occur when the roller around the belt unit is repeatedly passed. In particular, such damage on the surface of the photosensitive layer tends to appear on the image and directly impairs the image quality, which is a major factor limiting the life of the photoreceptor. That is, in order to develop a long-life photoconductor, it is essential to increase the mechanical strength as well as the electrical and chemical durability.

  In the case of a general photoreceptor having no functional layer such as a surface protective layer, it is the photosensitive layer that receives such a load. The photosensitive layer is usually composed of a binder resin and a photoconductive substance, and it is the binder resin that substantially determines the strength. However, since the content of the photoconductive substance must be considerably increased, sufficient machinery is required. It has not reached strength.

  Examples of the binder resin for the photosensitive layer include vinyl polymers such as polymethyl methacrylate, polystyrene, and polyvinyl chloride, and copolymers thereof, thermoplastic resins such as polycarbonate, polyester, polysulfone, phenoxy, epoxy, and silicone resin, and various kinds of heat. A curable resin is used. Among the various binder resins, the polycarbonate resin has a relatively excellent performance, and various polycarbonate resins have been developed and put into practical use (for example, see Patent Documents 3 to 6).

On the other hand, in order to give the strength of the photosensitive layer, a method of reducing the content of the photoconductive substance has been proposed, but in such a case, in the sheet-like photoreceptor, the curl (warp) of the sheet is increased. There is a detrimental effect, and there is a restriction that the thickness of the conductive support to be used must be increased (for example, see Patent Document 7).
Japanese Utility Model Publication No. 06-016966 JP 2000-010315 A JP 50-098332 A JP 59-071057 A JP 59-184251 JP 05-021478 A JP 2000-267318 A

  The surface of a conventional photoreceptor is worn or scratched by a practical load such as development with toner, friction with a transfer member or paper, friction with a cleaning member (blade), bending with a roller, or the like. However, the present situation is that the printing performance is limited in practical use. Further, when processing into a belt or winding around a drum, there are cases where processing and accuracy defects occur due to the curl of the sheet.

  The present invention has been made to solve such problems. That is, the object of the present invention is to provide a sheet-shaped or belt-shaped electrophotographic photoreceptor excellent in abrasion resistance to practical loads, having high mechanical strength, excellent handleability, and excellent electrical characteristics. It is to provide.

  As a result of intensive studies, the present inventors have included a binder resin containing a resin having a specific structure in the photosensitive layer, thereby having sufficient mechanical properties, easy handling, and even better electrical properties. As a result, the present invention has been completed.

（式（１）中、Ｒ^１は水素原子又はアルキル基を示し、Ｒ^２は炭素数８以下のアルキル基を示し、Ｒ^３及びＲ^４は同一でも異なっていてもよいアルキル基を示し、ｎ及びｍは１〜４の整数を示す。） That is, the present invention includes an electrophotographic photosensitive member having a photosensitive layer on a sheet-like conductive support, wherein the photosensitive layer contains a binder resin containing a polycarbonate resin having a repeating structure represented by the following formula (1): An electrophotographic photosensitive member is provided.

(In Formula (1), R ¹ represents a hydrogen atom or an alkyl group, R ² represents an alkyl group having 8 or less carbon atoms, R ³ and R ⁴ represent an alkyl group which may be the same or different, and n And m represents an integer of 1 to 4.)

  The present invention also resides in an image forming apparatus equipped with the above electrophotographic photosensitive member.

  According to the present invention, it is possible to obtain a sheet-like or belt-like electrophotographic photoreceptor excellent in handleability, excellent in abrasion resistance, and excellent in electrical characteristics. Further, when the sheet is processed into a belt or wound around a drum, the sheet can be prevented from curling.

  Hereinafter, the best mode for carrying out the present invention will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

  The electrophotographic photosensitive member of the present invention has a sheet-like conductive support, and the photosensitive layer contains a polycarbonate resin having a repeating structure represented by the formula (1). The polycarbonate resin is a conductive material of the photosensitive member. Used as a binder resin for a photosensitive layer provided on a support.

  The specific structure of the photosensitive layer in the electrophotographic photosensitive member of the present invention includes a charge generation layer mainly composed of a charge generation material, a charge transport material and a charge transport layer mainly composed of a binder resin on a conductive support. A laminated type photoreceptor in which a charge generating material is dispersed in a layer containing a charge transport material and a binder resin on a conductive support, and the like (single layer type) photoreceptor, etc. It is done. The polycarbonate resin represented by the formula (1) in the present invention is not particularly limited as long as it is contained in the photosensitive layer, and may be contained in any layer, but in a single-layer type photoreceptor, it is used for the photosensitive layer. In a laminated type photoreceptor, it is preferably used for a charge transport layer. Particularly preferably, it is used for a charge transport layer of a multilayer photoreceptor.

<Conductive support>
The conductive support of the present invention may be any sheet as long as it is in the form of a sheet, but preferably has flexibility, and examples thereof include resin and paper. Among them, a biaxially stretched film laminated with a metal layer is preferable. As the material of the biaxially stretched film, linear polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyolefin resins such as polyethylene and polypropylene, polychlorinated A vinyl resin etc. are mentioned. Among these, linear polyester resins, particularly polyethylene terephthalate, are preferable from the viewpoint of mechanical strength, dimensional stability, and the like. In addition, the thickness of an electroconductive support body is 30-150 micrometers normally, Preferably it is 50-120 micrometers, More preferably, it is 70-100 micrometers.

  Moreover, as a metal of the metal vapor deposition layer which comprises an electroconductive support body, copper, nickel, zinc, aluminum, ITO (indium-tin oxide) etc. are mentioned, Among these, aluminum is preferable. In addition, the film thickness of a metal vapor deposition layer is about 40-100 nm normally, and vapor deposition to the said resin film is well-known vapor deposition, such as an electrothermal heating melt vapor deposition method, an ion beam vapor deposition method, and an ion plating method. Made by law.

  Moreover, as a metal layer which comprises an electroconductive support body, metal foil, such as aluminum foil and nickel foil, and the laminate film which laminated | stacked these metals can be used. In this case, the metal foil is preferably 5 μm or less. Further, a conductive material having an appropriate resistance value can be laminated on the metal foil.

  The support surface may be smooth, or may be roughened by mixing particles having a large particle diameter with a resin.

（式（１）中、Ｒ^１は水素原子又はアルキル基を示し、Ｒ^２は炭素数８以下のアルキル基を示し、Ｒ^３及びＲ^４は同一でも異なっていてもよいアルキル基を示し、ｎ及びｍは１〜４の整数を示す。） <Binder resin>
The photosensitive layer of the electrophotographic photoreceptor of the present invention contains a polycarbonate resin having a repeating structure represented by the following formula (1).

(In Formula (1), R ¹ represents a hydrogen atom or an alkyl group, R ² represents an alkyl group having 8 or less carbon atoms, R ³ and R ⁴ represent an alkyl group which may be the same or different, and n And m represents an integer of 1 to 4.)

In formula (1), R ¹ represents a hydrogen atom or an alkyl group. The alkyl group in R ¹ may be a chain alkyl group or a cycloalkyl group, and may be a linear alkyl group or a branched alkyl group, but is preferably a chain alkyl group, particularly preferably a linear alkyl group. The number of carbon atoms of the alkyl group in R ¹ is not particularly limited, but is preferably 8 or less, particularly preferably 6 or less, and further preferably 4 or less. Examples of the alkyl group for R ¹ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, and a dodecyl group. When the number of carbons is too large, curling (warping) of the sheet, which is one of the problems, may increase. R ¹ is particularly preferably a hydrogen atom or a methyl group, and more preferably a hydrogen atom, in order to further obtain the effects of the present invention.

In the formula (1), R ² represents an alkyl group having 8 or less carbon atoms. The alkyl group in R ² may be a chain alkyl group or a cycloalkyl group, and may be a linear alkyl group or a branched alkyl group, but is preferably a chain alkyl group, particularly preferably a linear alkyl group. The number of carbon atoms of the alkyl group in R ² is preferably 6 or less, and particularly preferably 4 or less. R ¹ and R ² may be bonded to each other to form a ring. In this case, the two benzene rings in the formula (1) are connected by cycloalkylidene. Examples of the alkyl group for R ² include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a heptyl group, and an octyl group. In the case of an alkyl group having 9 or more carbon atoms, the curl (warpage) of the sheet may be increased. Further, when R ¹ is a hydrogen atom and R ² is also a hydrogen atom, the binding property may be lowered and the photosensitive layer may be peeled off. R ² is particularly preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and more preferably a methyl group, in order to further obtain the effects of the present invention.

In formula (1), R ³ represents an alkyl group that may be the same or different, and R ⁴ represents an alkyl group that may be the same or different. The alkyl group in R ³ and R ⁴ may be a chain alkyl group or a cycloalkyl group, and may be a linear alkyl group or a branched alkyl group, but a chain alkyl group is preferable, and a linear alkyl group is particularly preferable. . The number of carbon atoms of the alkyl group in R ³ and R ⁴ is not particularly limited, but is preferably 8 or less, particularly preferably 6 or less, and further preferably 4 or less. Examples of the alkyl group in R ³ and R ⁴ include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, and a dodecyl group. If the number of carbons is too large, the sheet curl may be increased. R ³ and / or R ⁴ are particularly preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and more preferably a methyl group, in order to obtain the effects of the present invention.

In formula (1), n and m represent an integer of 1 to 4, but 1 is preferable. The bonding position of R ³ and / or R ⁴ is not particularly limited, but it is bonded to the 3rd position of the benzene ring as viewed from the central linked carbon (the position of the benzene ring to which the central linked carbon is bonded is the 1st position). It is preferable. Further, the relationship between the bonding position of the central linking carbon and the oxygen atom to the benzene ring is not particularly limited, but the p-position is preferable.

  The molecular weight of the polycarbonate resin having the repeating structure represented by the formula (1) is not particularly limited, but is preferably 10,000 to 100,000, particularly preferably 20,000 to 50,000, as the viscosity average molecular weight Mv. If the viscosity average molecular weight Mv is too large, problems in coating and sheet processing may occur. On the other hand, if the viscosity average molecular weight Mv is too small, the wear resistance may be inferior.

  Even if the electrophotographic photosensitive member containing the polycarbonate resin having the repeating structure represented by the formula (1) is in a sheet form, the warping phenomenon can be suppressed. In particular, curling (warping) of the sheet-like electrophotographic photosensitive member can be suppressed even if the content of the charge transfer agent described below is reduced.

A method for producing a polycarbonate resin having a repeating structure represented by the formula (1) is not particularly limited. For example, when all of R ^{1 to} R ⁴ are methyl groups, JP-A-63-148263 is disclosed. Therefore, the production method can be synthesized by modifying the production method according to a conventional method.

  The photosensitive layer of the electrophotographic photoreceptor of the present invention can contain “other resins” other than the polycarbonate resin. The “other resin” used in combination here is a vinyl polymer such as polymethyl (meth) acrylate, polystyrene, polyvinyl chloride or a copolymer thereof; a polycarbonate resin other than the above polycarbonate resin; a polyarylate resin; a polyester resin; Polyester polycarbonate resin; thermoplastic resins such as polysulfone, phenoxy, epoxy, and silicone resin, various thermosetting resins, and the like. Among these resins, polycarbonate resins other than the above polycarbonate resins or polyarylate resins are preferable.

  The mixing ratio of the resin to be used in combination is not particularly limited, but in order to sufficiently obtain the above effect of the present invention, the “other resin” is used with respect to 100 parts by mass of the polycarbonate resin having the repeating structure represented by the formula (1). "Is preferably 100 parts by mass or less, more preferably 60 parts by mass or less, still more preferably 40 parts by mass or less, and particularly preferably not using" other resin "in combination.

<Underlayer>
An undercoat layer may be provided between the conductive support and the photosensitive layer in order to improve adhesion and blocking properties. As the undercoat layer, a resin, a resin in which particles such as a metal oxide are dispersed, or the like is used.

  Examples of metal oxide particles used for the undercoat layer include metal oxide particles containing one kind of metal element such as titanium oxide, aluminum oxide, silicon oxide, zirconium oxide, zinc oxide, iron oxide; calcium titanate, Examples thereof include metal oxide particles containing a plurality of metal elements such as strontium titanate and barium titanate. Only one type of particles may be used, or a plurality of types of particles may be mixed and used. Among these metal oxide particles, titanium oxide and aluminum oxide are preferable, and titanium oxide is particularly preferable.

  The surface of the titanium oxide particles may be treated with an inorganic substance such as tin oxide, aluminum oxide, antimony oxide, zirconium oxide, or silicon oxide, or an organic substance such as stearic acid, polyol, or silicone. As the crystal form of the titanium oxide particles, any of rutile, anatase, brookite, and amorphous can be used. A thing of a several crystalline state may be contained.

  Various particles can be used as the particle size, and the average primary particle size is preferably 10 nm or more and 100 nm or less, particularly preferably 10 nm or more and 50 nm or less, from the viewpoint of characteristics and liquid stability.

  The undercoat layer is preferably formed in a form in which particles are dispersed in a binder resin. As binder resin used for the undercoat layer, phenoxy, epoxy, polyvinylpyrrolidone, polyvinyl alcohol, casein, polyacrylic acid, celluloses, gelatin, starch, polyurethane, polyimide, polyamide, etc. are used alone or in a cured form together with a curing agent. Among them, alcohol-soluble copolymerized polyamides, modified polyamides and the like are preferable because they exhibit good dispersibility and coating properties.

  The content ratio of the particles with respect to the binder resin can be arbitrarily selected, but it is preferably used in the range of 10% by mass to 500% by mass in terms of the stability of the dispersion and the coating property.

  The thickness of the undercoat layer can be arbitrarily selected, but is preferably from 0.1 μm to 25 μm from the viewpoint of photoreceptor characteristics and applicability. Moreover, you may add a well-known antioxidant etc. to an undercoat layer.

<Charge generation layer>
When the electrophotographic photoreceptor of the present invention is a multilayer photoreceptor, examples of the charge generation material used for the charge generation layer include selenium and its alloys, cadmium sulfide, other inorganic photoconductive materials, phthalocyanine pigments, Various photoconductive materials such as organic pigments such as azo pigments, quinacridone pigments, indigo pigments, perylene pigments, polycyclic quinone pigments, anthanthrone pigments, and benzimidazole pigments can be used, and organic pigments, phthalocyanine pigments, and azo pigments are particularly preferable. These fine particles are, for example, polyester resin, polyvinyl acetate, polyacrylate ester, polymethacrylate ester, polyester, polycarbonate, polyvinyl acetoacetal, polyvinyl propional, polyvinyl butyral, phenoxy resin, epoxy resin, urethane resin, cellulose ester, cellulose. Used in a form bound with various binder resins such as ether. The use ratio in this case is used in the range of 30 to 500 parts by mass with respect to 100 parts by mass of the binder resin, and the film thickness is usually 0.1 μm to 1 μm, preferably 0.15 μm to 0.6 μm.

  When a phthalocyanine compound is used as the charge generation material, specifically, a metal such as metal-free phthalocyanine, copper, indium, gallium, tin, titanium, zinc, vanadium, silicon, germanium, or an oxide or halide thereof. Phthalocyanines are used. Examples of the ligand to a metal atom having 3 or more valences include a hydroxyl group and an alkoxy group in addition to the oxygen atom and chlorine atom shown above. Particularly preferred are X-type, τ-type metal-free phthalocyanine, titanyl phthalocyanine such as A-type, B-type, and D-type, vanadyl phthalocyanine, chloroindium phthalocyanine, chlorogallium phthalocyanine, and hydroxygallium phthalocyanine.

  Of the crystal forms of titanyl phthalocyanine mentioned here, A type and B type are described in W.W. Heller et al. Have shown them as phase I and phase II, respectively (Zeit. Kristallogr. 159 (1982) 173), and type A is known as a stable type. The D-type is a crystal type characterized by a clear peak at a diffraction angle 2θ ± 0.2 ° of 27.3 ° in powder X-ray diffraction using CuKα rays.

  The phthalocyanine compound may be a single compound or may be in some mixed state. As the mixed state that can be placed in the phthalocyanine compound or crystal state here, the respective constituent elements may be mixed and used later, or the mixed state may be used in the production / treatment process of the phthalocyanine compound such as synthesis, pigmentation, and crystallization. It may be generated. As such treatment, acid paste treatment, grinding treatment, solvent treatment and the like are preferable.

<Charge transport layer>
The charge transport layer of the multilayer photoreceptor contains a charge transport material and usually contains a binder resin and other components used as necessary. Specifically, such a charge transport layer is prepared by, for example, preparing a coating solution by dissolving or dispersing a charge transport material and a binder resin in a solvent. In the case of a reverse lamination type photosensitive layer, it can be obtained by coating and drying on a conductive support (on the undercoat layer when an undercoat layer is provided).

  The charge transport material is not particularly limited, and any material can be used. Examples of known charge transport materials include aromatic nitro compounds such as 2,4,7-trinitrofluorenone, cyano compounds such as tetracyanoquinodimethane, electron withdrawing materials such as quinone compounds such as diphenoquinone, and carbazole derivatives. , Indole derivatives, imidazole derivatives, oxazole derivatives, pyrazole derivatives, thiadiazole derivatives, heterocyclic compounds such as benzofuran derivatives, aniline derivatives, hydrazone derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives and multiple types of these compounds Or an electron donating substance such as a polymer having a group composed of these compounds in the main chain or side chain. Among these, carbazole derivatives, aromatic amine derivatives, stilbene derivatives, butadiene derivatives, enamine derivatives, and those in which a plurality of these compounds are bonded are preferable. Any one of these charge transport materials may be used alone, or two or more thereof may be used in any combination.

  Specific examples of suitable structures of the charge transport material are shown below. These specific examples are shown for illustration, and any known charge transporting material may be used as long as it does not contradict the gist of the present invention.

  The charge transport layer is formed in such a form that these charge transport materials are bound to a polycarbonate resin having a repeating structure represented by the formula (1) and a binder resin composed of the “other resin”. The charge transport layer may be composed of a single layer, or may be a stack of a plurality of layers having different constituent components or composition ratios.

  The content ratio of the binder resin and the charge transport material in the photosensitive layer is usually in the range of 30 to 200 parts by weight, preferably 40 to 150 parts by weight with respect to 100 parts by weight of the binder resin. In the present invention, the effect of using the polycarbonate resin having the repeating structure represented by the formula (1) is remarkable particularly when the content ratio of the charge transport material is small, and the charge transport material is contained in 100 parts by mass of the binder resin. Preferably, the effect becomes remarkable at 65 parts by mass or less, more preferably 55 parts by mass or less, and further preferably 45 parts by mass or less. Here, when two or more kinds of charge transport materials are contained in the photosensitive layer, the above-mentioned “parts by mass” means a total part by mass of all contained charge transport materials.

  The film thickness of the charge transport layer is generally 5 to 50 μm, preferably 10 to 45 μm, but the above effect of the present invention in which the binder resin contains a polycarbonate resin having a repeating structure represented by the formula (1) is This is remarkable when the total film thickness of the charge generation layer and the charge transport layer is 22 μm or more. In particular, it becomes more prominent when the thickness of the charge transport layer is 22 μm or more.

  In order to improve film forming properties, flexibility, coating properties, stain resistance, gas resistance, light resistance, etc. for the charge transport layer, known plasticizers, antioxidants, ultraviolet absorbers, electron suction Additives such as functional compounds, dyes, pigments and leveling agents may be included. Examples of the antioxidant include hindered phenol compounds and hindered amine compounds. Examples of dyes and pigments include various pigment compounds and azo compounds.

<Dispersion (single layer) photosensitive layer>
In the case of a dispersion-type photosensitive layer, the above-mentioned charge generating material is used in the above-described (total mass of charge transporting material / total mass of binder resin) using the binder resin and charge transporting material as described above. Is distributed.

  In this case, the particle size of the charge generating material needs to be sufficiently small, and is preferably 1 μm or less, more preferably 0.5 μm or less. If the amount of the charge generating material dispersed in the photosensitive layer is too small, sufficient sensitivity cannot be obtained, and if it is too large, there are problems such as a decrease in chargeability and a decrease in sensitivity. It is preferably used in the range of 0.5 to 50% by mass, more preferably in the range of 1 to 20% by mass with respect to the entire photosensitive layer.

  The film thickness of the dispersion type (single layer type) photosensitive layer is usually 5 to 50 μm, more preferably 10 to 45 μm. However, when the thickness is 22 μm or more, the above-described effects of the present invention can be obtained more remarkably.

  In addition, known plasticizers for improving film formability, flexibility, mechanical strength, additives for suppressing residual potential, dispersion aids for improving dispersion stability, and coating properties are improved. Leveling agents and surfactants such as silicone oil, fluorine oil and other additives may be contained.

  A protective layer may be provided on the photosensitive layer for the purpose of preventing the photosensitive layer from being worn out or preventing or reducing the deterioration of the photosensitive layer due to a discharge product generated from a charger or the like. Further, for the purpose of reducing frictional resistance and wear on the surface of the photoreceptor, the surface layer may contain a fluorine-based resin, a silicone resin, or the like. Moreover, the particle | grains which consist of these resin, and the particle | grains of an inorganic compound may be included.

<Measurement method of photosensitive layer thickness>
The film thickness of the photosensitive layer can be measured by the following method. That is, in the photosensitive sheet coated by a known method, first, the total thickness of the support and the undercoat layer is measured using the coating start portion or the coating end portion. That is, the photosensitive layer is peeled off using a solvent capable of dissolving the photosensitive layer (generally, a solvent used for coating). At this time, if there is an undercoat layer, it is necessary that the solvent does not dissolve the undercoat layer. In the case of a single layer type photoreceptor, the photosensitive layer is peeled off as it is, and in the case of a laminated type photoreceptor in which a charge generation layer and a charge transport layer are laminated, both layers are peeled off. The film thickness of the peeled portion is the thickness of the conductive support (including the undercoat layer if it has an undercoat layer).

  On the other hand, for the coated portion of the photosensitive layer, the film thickness of the entire sheet-like electrophotographic photosensitive member is measured at any 10 points including the coating width direction and the coating progression direction, and the average value is calculated. The film thickness of the photosensitive layer is measured by taking the difference between the total film thickness and the film thickness of the conductive support (including the undercoat layer if it has an undercoat layer) examined in advance.

  That is, in the case of a single layer type photoreceptor, the thickness of the photosensitive layer itself is defined. In the case of a laminated type photoreceptor, the thickness of the photosensitive layer is defined by the thickness of two layers of the charge generation layer and the charge transport layer. To do.

  The film thickness is defined as a value measured by a digital electronic micrometer (K351C type manufactured by Anritsu Corporation) using a probe having a diameter of 2 mm.

<Method for preparing electrophotographic photoreceptor>
The method for preparing the electrophotographic photosensitive member of the present invention is not particularly limited. Usually, each layer constituting these photosensitive members is known as a method for forming a photosensitive layer of a sheet-like electrophotographic photosensitive member, a die coating method, a reverse coating method, It is formed by coating on a sheet-like conductive support by a gravure coating method, a bar coating method or the like. As a method for forming each layer, a known method such as sequentially applying a coating solution obtained by dissolving or dispersing a substance contained in a layer in a solvent can be applied.

  The coated photoreceptor is subjected to a drying process until the solvent of the coating film is substantially removed by evaporation. As a drying method, a known method can be applied. For example, the drying is performed by a heating roller, a hot air dryer, the dryer, an infrared dryer, and / or a far infrared dryer, and the drying temperature is usually 60 to 60. It is carried out in the range of 140 ° C.

  The sheet-like electrophotographic photoreceptor thus obtained is subjected to a process of cutting to an appropriate size as necessary. For example, both ends thereof are joined by an ultrasonic fusion method or the like, In addition to being used as a “formed electrophotographic photosensitive member”, it can also be suitably used by winding it around a drum as it is. The belt is preferably an endless belt. Further, when winding around a drum, a roll wound thinly may be held inside the drum and unwound, or a single sheet may be wound. An electrophotographic photosensitive member having a photosensitive layer containing a polycarbonate resin having a repeating structure represented by the formula (1) as a binder resin is used as a sheet-like electrophotographic photosensitive member, in particular, forming a belt. Is particularly suitable.

<Image forming apparatus>
Next, an embodiment of an image forming apparatus using the electrophotographic photosensitive member of the present invention will be described with reference to FIG. However, the present invention is not limited to the following description using FIG. 1, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

  As shown in FIG. 1, the image forming apparatus includes an electrophotographic photosensitive member 1, a charging device 2, an exposure device 3, and a developing device 4, and further, a transfer device 5, a cleaning device 6, and a fixing device as necessary. A device (not shown) is provided.

  The electrophotographic photosensitive member 1 is not particularly limited as long as it is the above-described electrophotographic photosensitive member of the present invention. In FIG. 1, as an example, the above-described photosensitive layer is formed on the surface of a sheet-like conductive support, 2 shows a photoreceptor in which an endless belt is formed by sonic fusion. A charging device 2, an exposure device 3, a developing device 4, a transfer device 5, and a cleaning device 6 are arranged along the outer peripheral surface of the electrophotographic photoreceptor 1.

  The charging device 2 charges the electrophotographic photosensitive member 1 and uniformly charges the surface of the electrophotographic photosensitive member 1 to a predetermined potential. In FIG. 1, a corona discharge type charging device (corotron) is shown as an example of the charging device 2, but a corona charging device such as a scorotron; a contact type charging device such as a charging roller or a charging brush is also used. .

  In many cases, the electrophotographic photosensitive member 1 and the charging device 2 are designed to be removable from the main body of the image forming apparatus as a cartridge including both of them (hereinafter referred to as “photosensitive cartridge” as appropriate). . For example, when the electrophotographic photoreceptor 1 or the charging device 2 is deteriorated, the photoreceptor cartridge can be detached from the image forming apparatus main body, and another new photoreceptor cartridge can be mounted on the image forming apparatus main body. It has become. Also, the toner described later is often stored in the toner cartridge and designed to be removable from the main body of the image forming apparatus. When the toner in the used toner cartridge runs out, this toner cartridge is removed. It can be removed from the main body of the image forming apparatus and another new toner cartridge can be mounted. Further, a cartridge equipped with all of the electrophotographic photosensitive member 1, the charging device 2, and the toner may be used.

  The type of the exposure apparatus 3 is not particularly limited as long as it can expose the electrophotographic photoreceptor 1 to form an electrostatic latent image on the photosensitive surface of the electrophotographic photoreceptor 1. Specific examples include halogen lamps, fluorescent lamps, lasers such as semiconductor lasers and He—Ne lasers, LEDs, and the like. Further, exposure may be performed by a photoreceptor internal exposure method. The light used for the exposure is arbitrary. For example, the exposure may be performed using monochromatic light with a wavelength of 780 nm, monochromatic light with a wavelength slightly shorter than 600 nm to 700 nm, or monochromatic light with a wavelength shorter than 380 nm to 500 nm. .

  The type of the developing device 4 is not particularly limited, and any device such as a dry development method such as cascade development, one-component conductive toner development, two-component magnetic brush development, or a wet development method can be used.

  The type of toner is arbitrary, and in addition to melt-pulverized toner, polymerized toner using suspension polymerization method, emulsion polymerization aggregation method, or the like can be used. In particular, when a polymerized toner is used, it is preferable that the volume average particle size is a small particle size of about 4 to 8 μm, and the toner particle shape is from a nearly spherical shape to a shape outside the spherical shape on the potato. Can be used in various ways. The polymerized toner is excellent in charging uniformity and transferability and is suitably used for high image quality.

  The type of the transfer device 5 is not particularly limited, and an apparatus using an arbitrary system such as an electrostatic transfer method such as corona transfer, roller transfer, or belt transfer, a pressure transfer method, or an adhesive transfer method can be used. . Here, the transfer device 5 includes a transfer charger, a transfer roller, a transfer belt, and the like that are disposed to face the electrophotographic photosensitive member 1. The transfer device 5 applies a predetermined voltage value (transfer voltage) having a polarity opposite to the charging potential of the toner, and transfers the toner image formed on the electrophotographic photosensitive member 1 onto a recording paper (paper, medium) P. It is.

  There is no restriction | limiting in particular about the cleaning apparatus 6, Arbitrary cleaning apparatuses, such as a brush cleaner, a magnetic brush cleaner, an electrostatic brush cleaner, a magnetic roller cleaner, a blade cleaner, can be used. The cleaning device 6 is for scraping off residual toner adhering to the photoreceptor 1 with a cleaning member and collecting the residual toner.

  When the toner transferred onto the recording paper P passes through the fixing device, the toner is heated and heated to a molten state, and is cooled after passing through to fix the toner on the recording paper P. The type of the fixing device is not particularly limited, and a fixing device of an arbitrary system such as heat roller fixing, flash fixing, oven fixing, pressure fixing, or the like can be provided.

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

  Subsequently, the photosensitive surface of the charged photoreceptor 1 is exposed by the exposure device 3 according to the image to be recorded, and an electrostatic latent image is formed on the photosensitive surface. The developing device 4 develops the electrostatic latent image formed on the photosensitive surface of the photoreceptor 1.

  When the charged toner carried on the developing roller 4 comes into contact with the surface of the photoreceptor 1, a toner image corresponding to the electrostatic latent image is formed on the photosensitive surface of the photoreceptor 1. This toner image is transferred onto the recording paper P by the transfer device 5. Thereafter, the toner remaining on the photosensitive surface of the photoreceptor 1 without being transferred is removed by the cleaning device 6.

  After the transfer of the toner image onto the recording paper P, the final image is obtained by passing the toner image through the fixing device and thermally fixing the toner image onto the recording paper P.

  In addition to the above-described configuration, the image forming apparatus may have a configuration capable of performing a static elimination process, for example. The neutralization step is a step of neutralizing the electrophotographic photosensitive member by exposing the electrophotographic photosensitive member, and a fluorescent lamp, an LED, or the like is used as the neutralizing device. In addition, the light used in the static elimination process is often light having an exposure energy that is at least three times that of the exposure light.

  Further, the image forming apparatus may be further modified and configured, for example, a configuration capable of performing processes such as a pre-exposure process and an auxiliary charging process, a structure performing offset printing, and a plurality of types. It is also possible to adopt a full-color system configuration using the above toner. In particular, the photoreceptor forming the endless belt is suitable for four-cycle full-color printing in which each color image is repeatedly developed.

  Hereinafter, based on an Example, embodiment of this invention is described more concretely. In addition, the following examples are shown in order to describe the present invention in detail, and the present invention is not limited to the examples shown below unless it is contrary to the gist thereof. In the following examples and comparative examples, “parts” indicates “parts by mass” unless otherwise specified, and “%” indicates “% by mass” unless otherwise specified.

<Measurement of viscosity average molecular weight Mv of binder resin>
The measurement of the viscosity average molecular weight Mv of the binder resin will be described. That is, the binder resin is dissolved in dichloromethane to prepare a solution having a concentration C of 6.00 g / L. Using a Ubbelohde capillary viscometer with a solvent (dichloromethane) flow time t ₀ of 136.16 seconds, the sample solution flow time t (seconds) is measured in a constant temperature water bath set at 20.0 ° C. The viscosity average molecular weight Mv is calculated according to the following formula.
a = 0.438 × η _sp +1 η _sp = (t / t ₀ ) −1
b = 100 × η _sp / C C = 6.00 (g / L)
η = b / a
Mv = 3207 × η ^1.205

<Manufacture of photoreceptor sheet>
Comparative example A
Rutile type titanium oxide having an average primary particle size of 40 nm (“TTO55N” manufactured by Ishihara Sangyo Co., Ltd.) and 3% methyldimethoxysilane (“TSL8117” manufactured by Toshiba Silicone Co., Ltd.) with respect to the titanium oxide are mixed and kneaded at high speed. The surface-treated titanium oxide obtained by mixing at a high speed at a rotational peripheral speed of 34.5 m / sec in a mixed solvent of methanol / 1-propanol in a ball mill. To obtain a dispersion slurry of hydrophobized titanium oxide.

  The dispersion slurry, a mixed solvent of methanol / 1-propanol / toluene, and ε-caprolactam [compound represented by the following formula (A)] / bis (4-amino-3-methylcyclohexyl) methane [the following formula (B Compound represented by the following formula (C)] / decamethylene dicarboxylic acid [compound represented by the following formula (D)] / octadecamethylene dicarboxylic acid [in the following formula (E) The compositional molar ratio of the compound represented] is 60% / 15% / 5% / 15% / 5% of the copolymerized polyamide pellets with heating and stirring and mixing to dissolve the polyamide pellets. By performing sonic dispersion treatment, the mass ratio of methanol / 1-propanol / toluene is 7/1/2, and hydrophobically treated titanium oxide / co- Containing a slip polyamide in a weight ratio 3/1 was a solid concentration of 18.0% of the undercoat layer dispersion.

  The undercoat layer-forming coating solution thus obtained was applied onto a polyethylene terephthalate sheet having aluminum deposited on the surface with a wire bar so that the film thickness after drying was 1.2 μm, and dried. Was provided.

  Next, 10 parts of oxytitanium phthalocyanine having a powder X-ray diffraction spectrum shown in FIG. 2 is obtained by showing a strong diffraction peak with a Bragg angle (2θ ± 0.2) of 27.3 ° in X-ray diffraction by CuKα rays. In addition to 150 parts of 2-dimethoxyethane, pulverization and dispersion treatment was performed with a sand grind mill to prepare a pigment dispersion. To 160 parts of the pigment dispersion thus obtained, 100 parts of a 5% 1,2-dimethoxyethane solution of polyvinyl butyral (trade name # 6000C, manufactured by Denki Kagaku Kogyo Co., Ltd.) and an appropriate amount of 1,2-dimethoxyethane are added. In addition, a dispersion having a solid content concentration of 4.0% was finally produced.

  The dispersion was applied on the undercoat layer with a wire bar so that the film thickness after drying was 0.4 μm, and then dried to form a charge generation layer.

  Next, 50 parts of a charge transport material of the following hydrazone compound, 100 parts of a polycarbonate resin (viscosity average molecular weight 30000) comprising the following repeating unit (1-1), silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) as a leveling agent 0.05 parts of KF96-10CS ") was mixed with 640 parts of a mixed solvent of tetrahydrofuran and toluene (tetrahydrofuran 80%, toluene 20%) to prepare a coating solution for forming a charge transport layer.

  This solution is applied onto the above-described charge generation layer using an applicator so that the film thickness after drying is 25 μm, and dried at 125 ° C. for 20 minutes to form a charge transport layer, thereby producing a photoreceptor sheet A. did.

Example 2
The polycarbonate resin composed of the repeating unit (1-1) used in the coating liquid for forming the charge transport layer in Example 1 was changed to the polycarbonate resin composed of the following repeating unit (1-2) (viscosity average molecular weight 30000). Produced a photoreceptor sheet B in the same manner as in Example 1.

Comparative Example 1
The polycarbonate resin consisting of the repeating unit (1-1) used in the coating solution for forming the charge transport layer of Example 1 was replaced with the polycarbonate resin consisting of the following repeating unit (2-1) (bisphenol Z type) (viscosity average molecular weight). Photosensitive sheet C was produced in the same manner as in Example 1 except that 30000).

Comparative Example 2
The polycarbonate resin composed of the repeating unit (1-1) used in the coating liquid for forming the charge transport layer of Example 1 was replaced with the polycarbonate resin (viscosity average molecular weight) composed of the following repeating unit (2-2) (bisphenol A type). The resin sheet was prepared in the same manner as in Example 1 except that it was changed to 30000), but this resin was not dissolved in a mixed solvent of tetrahydrofuran / toluene. Therefore, the photoreceptor sheet D was produced by setting the solvent to 100% 1,4-dioxane.

  The manufactured photoreceptor sheets A, B, C and D were subjected to the following electrical property test and wear test. These results are summarized in Table 1.

<Electrical characteristics test>
An electrophotographic characteristic evaluation apparatus manufactured according to the electrophotographic society measurement standard (basic and applied electrophotographic technology, edited by the Electrophotographic Society, Corona, pages 404 to 405) is used, and the photosensitive sheet is 80 mm in diameter. Affixed to an aluminum drum to form a cylindrical shape, and the aluminum drum and the aluminum support of the photosensitive sheet are electrically connected. Then, the drum is rotated at a constant rotational speed of 60 rpm to perform charging, exposure, potential measurement, and static elimination. An electrical property evaluation test by cycle was performed. At that time, the surface after 100 ms when the initial surface potential of the photosensitive member is charged to −700 V and the light of the halogen lamp is converted to monochromatic light of 780 nm with an interference filter is exposed at 1.0 μJ / cm ^2. The potential (hereinafter abbreviated as “VL”) was measured. The measurement environment is a temperature of 25 ° C., a relative humidity of 50% (hereinafter abbreviated as “NN” or “NN environment”), and a temperature of 5 ° C. and a relative humidity of 10% (hereinafter abbreviated as “LL” or “LL environment”). Performed).

<Abrasion test>
The photoreceptor sheet was cut into a circle having a diameter of 10 cm, and an abrasion test was performed using a Taber abrasion tester (manufactured by Taber). The test conditions were measured at a weight of 23 ° C. and 50% RH using a wear wheel CS-10F (Type III) without load (the weight of the wear wheel) after 1000 rotations. The amount of wear was determined by taking the difference in mass before and after the wear test.

  From the results of Table 1, as shown in the results of the wear test, the photoconductors containing the polycarbonate resin having the repeating structure represented by the formula (1) like the photoconductors A and B of Examples 1 and 2 are shown in the results of the wear test. In addition, it was found to be excellent in wear resistance. Moreover, the electrical property showed the favorable result, without being inferior to the polycarbonate resin of the bisphenol Z type (repeating unit (2-1)) and the bisphenol A type (repeating unit (2-1)) used conventionally.

  Furthermore, in the polycarbonates composed of the repeating units (1-1) and (1-2) of Examples 1 and 2, there was no problem in solubility in the coating solvent. On the other hand, in the case of a polycarbonate resin of bisphenol A type (repeating unit (2-1)), a problem was confirmed in solubility in a solvent.

Comparative example B
Aluminum is deposited in a thickness of 70 nm on the surface of a biaxially stretched polyethylene terephthalate film with a film thickness of 75 μm, the width of which is 500 mm, and the surface is roughened (Ra = 0.1 μm) by containing silica particles. A film was provided, wound up, and made into a roll having a length of 1000 m. Next, aluminum oxide particles having an average primary particle diameter of 13 nm (Aluminum Oxide C, manufactured by Nippon Aerosil Co., Ltd.) are dispersed by ultrasonication in a mixed solvent of methanol / 1-propanol to obtain a dispersion slurry of aluminum oxide. After stirring and mixing the dispersion slurry, a mixed solvent of methanol / 1-propanol (mass ratio 7/3), and the copolymerized polyamide pellets used in Comparative Example A to dissolve the polyamide pellets Then, an ultrasonic dispersion treatment was performed to obtain a dispersion having a solid content concentration of 8.0% containing aluminum oxide / copolymerized polyamide at a mass ratio of 1/1.

  This undercoat layer coating solution was applied using a reverse coat method while unwinding a roll of aluminum vapor-deposited polyethylene terephthalate film, so that the film thickness after drying was 0.5 μm. Was provided.

  Next, Bragg angles (2θ ± 0.2) are 9.3 °, 10.6 °, 13.2 °, 15.1 °, 15.7 °, 16.1 ° in X-ray diffraction by CuKα ray, Mix 10 parts of oxytitanium phthalocyanine showing strong diffraction peaks at 20.8 °, 23.3 °, 26.3 ° and 27.1 ° with 150 parts of 4-methoxy-4-methyl-2-pentanone A pigment dispersion was produced by grinding and dispersing with a grind mill. To this pigment dispersion, 50 parts of a 5% 1,2-dimethoxyethane solution of polyvinyl butyral (manufactured by Denki Kagaku Kogyo Co., Ltd., trade name Denkabutyral # 6000C), and phenoxy resin (trade name PKHH, manufactured by Union Carbide). A 5% 1,2-dimethoxyethane solution (50 parts) was mixed, and an appropriate amount of 1,2-dimethoxyethane was added to prepare a dispersion having a solid content concentration of 4.0%.

  The coating solution for the charge generation layer obtained in this manner was used to reverse the film thickness after drying on the roll of the aluminum vapor-deposited polyethylene terephthalate film on which the undercoat layer was formed. Was applied so as to be 0.4 μm, and a charge generation layer was provided.

  Next, 45 parts of a charge transport material composed of an isomer mainly composed of the following structure shown in JP-A-2002-080432, a polycarbonate resin composed of the above repeating unit (1-1) (viscosity average molecular weight 30000) 100 parts of antioxidant (product name: Irganox 1076, manufactured by Ciba Geigy), 0.05 part of silicone oil (“KF96-10CS” manufactured by Shin-Etsu Chemical Co., Ltd.) as a leveling agent, and a mixed solvent of tetrahydrofuran and toluene ( The mixture was mixed with 640 parts of tetrahydrofuran (80% tetrahydrofuran, 20% toluene) to prepare a coating solution for forming a charge transport layer.

  The coating solution for the charge transport layer thus obtained was dried on the die coating method while unrolling the roll of the aluminum vapor-deposited polyethylene terephthalate film on which the undercoat layer and the charge generation layer were formed. The film was applied so that the film thickness was 22 μm, and a charge transport layer was provided.

  The roll-like sheet coated with the photosensitive layer thus obtained was cut into a size of 381 mm × 245 mm using a continuous cutting machine, provided with guide ribs and conductive bands at appropriate positions, and both ends overlapped by 1 mm. The electrophotographic photosensitive member E having a width of 245 mm and a peripheral length of 380 mm was obtained by ultrasonic welding.

Example 4
Except that the polycarbonate resin consisting of the repeating unit (1-1) used in the coating liquid for forming the charge transport layer of Example 3 was changed to the polycarbonate resin consisting of the repeating unit (1-2) (viscosity average molecular weight 30000), In the same manner as in Example 3, a photoreceptor belt F was produced.

Comparative Example 3
Instead of the polycarbonate resin comprising the repeating unit (1-1) used in the coating solution for forming the charge transport layer of Example 3, a polycarbonate resin comprising the repeating unit (2-3) having the following structure (viscosity average molecular weight 30000) A photoconductor belt G was produced in the same manner as in Example 3 except that.

Comparative Example 4
The polycarbonate resin composed of the repeating unit (1-1) used in the coating liquid for forming a charge transport layer in Example 3 was changed to the polycarbonate resin composed of the repeating unit (2-1) (viscosity average molecular weight 30000). Produced a photoreceptor belt H in the same manner as in Example 3.

Comparative Example 5
Photosensitive belt I was prepared in the same manner as in Comparative Example 3, except that the amount of the charge transport material used in the charge transport layer forming coating solution of Comparative Example 3 was changed from 45 parts to 70 parts.

Comparative Example 6
A photoreceptor belt J was produced in the same manner as in Comparative Example 4 except that the amount of the charge transport material used in the charge transport layer forming coating solution of Comparative Example 4 was changed from 45 parts to 70 parts.

  The manufactured photoreceptor belts E to J were subjected to the following electrical property test and actual machine test. These results are summarized in Table 2.

<Electrical characteristics test>
Cut out the roll sheet used to create the photoreceptor belt, attach the sheet to an aluminum drum to form a cylinder, and measure the electrical characteristics by the same method as when measuring the photoreceptor sheets A to D. Thus, the electrical characteristics of the photoreceptor belts E to J were obtained.

<Evaluation of initial image by actual machine test>
Photosensitive belts E to J were respectively mounted on a commercially available laser beam printer Ipsio 2200 manufactured by Ricoh, and image evaluation was performed. The photoreceptor belts E, F, I, and J gave a good initial image by visual observation. However, the photoreceptor belts G and H had a belt wrapper due to the large curl of the photoreceptor sheet. Since the end portion was in contact with the scorotron charger in the actual machine, charging leak occurred and an initial image could not be obtained normally.

  Accordingly, among these, the photosensitive belts E, F, I, and J were subjected to a printing durability test using 10,000 actual machines with a 5% color image, and the amount of film loss from 22 μm was measured.

<Measurement method of film loss>
Using a digital electronic micrometer (K351C type manufactured by Anritsu Corporation), 10 points were arbitrarily selected from the photosensitive surface of the belt, and the total thickness including the sheet-like conductive support was measured. The total thickness was measured in the same manner after 10,000 plate life tests with the above apparatus, and the difference between the average values of the 10 points was defined as “film reduction amount”.

  From this, the photosensitive belts E and F of the examples showed good initial electrical characteristics, and a good image was obtained without causing the trouble that the belt became a trumpet shape and caused an image defect, Further, it was found that the amount of film loss was small and good printing durability was exhibited.

  On the other hand, as in Comparative Examples 3 and 4, for the purpose of reducing the amount of film loss, a polycarbonate resin that has been used in a large amount as in Comparative Examples 5 and 6 has been used. When the number of parts of the material is reduced, the electrical characteristics are within the allowable range, but the curl of the sheet becomes very large, making it difficult to make a belt, and the completed belt becomes a trumpet shape for practical use. A bug was invited.

  As described above, only when the polycarbonate resin having the repeating structure represented by the formula (1) is used, the number of parts of the charge transport material can be reduced, and the electrical characteristics, handling properties, and printing durability are excellent. It was found that a photoreceptor can be obtained for the first time.

  The electrophotographic photosensitive member of the present invention containing a polycarbonate resin having a repeating structure represented by the formula (1) as a binder resin is excellent in handleability, is excellent in wear resistance, and has a sheet shape or belt shape excellent in electrical characteristics. Since an electrophotographic photoreceptor can be obtained, it is widely used in printers, copiers, printing machines, and the like.

1 is a conceptual diagram illustrating an example of an image forming apparatus using an electrophotographic photosensitive member of the present invention. 2 is an X-ray diffraction pattern of oxytitanium phthalocyanine used as a charge generation material in Examples 1 and 2 and Comparative Examples 1 and 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Charging device 3 Exposure device 4 Developing device 5 Transfer device 6 Cleaning device P Recording paper

Claims (6)

An electrophotographic photosensitive member having a photosensitive layer on the sheet-like conductive substrate, electrophotography photosensitive layer is characterized by containing a polycarbonate resin comprising a repeating structure represented by at least the following formula (1 -2) Photoconductor.

  The electrophotographic photosensitive member according to claim 1, wherein a belt is formed.   2. The photosensitive layer contains at least one or more kinds of charge transport materials, and contains a charge transport material in a proportion of 55 parts by mass or less with respect to 100 parts by mass of the binder resin in the photosensitive layer. The electrophotographic photosensitive member according to claim 2.   4. The electrophotographic photosensitive member according to claim 1, wherein a charge generation layer and a charge transport layer are laminated in this order on a sheet-like conductive support.   The electrophotographic photosensitive member according to claim 1, wherein the photosensitive layer has a thickness of 22 μm or more.   An image forming apparatus on which the electrophotographic photosensitive member according to any one of claims 1 to 5 is mounted.

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