JP2017198907A - Process cartridge and electrophotographic image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process cartridge that can suppress the occurrence of rubbing memory when a charging member excellent in rotation stability during driven rotation with respect to a photoreceptor is used as a charging member charging in contact with the photoreceptor.SOLUTION: There is provided a process cartridge provided with an electrophotographic photoreceptor and a charging member, wherein: the electrophotographic photoreceptor contains a resin having a structure represented by the following formula (1) in a charge transport layer that is a surface layer; the charging member contains a binder in a conductive resin layer that is a surface layer and includes resin particles 11 in a bowl shape with an opening such that the opening is held while exposed on the surface of the charging member; the surface of the charging member includes a concave part B1, convex parts C1, and exposed parts A1 of the conductive resin layer; and the exposed parts contain a silicone oil in an area from the surface to a depth of 50 nm.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a process cartridge and an electrophotographic image forming apparatus used in electrophotography.

  An electrophotographic image forming apparatus employing an electrophotographic system mainly includes an electrophotographic photosensitive member (hereinafter simply referred to as “photosensitive member”), a charging device, an exposure device, a developing device, a transfer device, and a fixing device. With these apparatuses, processes such as charging, exposure, development, transfer, and cleaning are repeatedly performed. Here, the photoconductor is required to have high lubricity with a process member that is in contact with the surface of the photoconductor, such as a cleaning blade for removing transfer residual toner. Patent Document 1 discloses a photoreceptor in which the surface lubricity is improved by including a siloxane compound in the surface layer of the photoreceptor.

  On the other hand, as a method of charging the surface of the photoconductor, a voltage (a voltage of only a DC voltage or a voltage obtained by superimposing an AC voltage on a DC voltage) is applied to a charging member placed in contact with or close to the surface of the photoconductor. Contact charging that charges the body is known. Patent Document 2 discloses a charging member having a concave portion derived from the opening of bowl-shaped resin particles and a convex portion derived from the edge of the opening as a charging member used for contact charging. According to this charging member, it is described that the rotational stability at the time of the driven rotation with respect to the photosensitive member can be improved by the elastic deformation of the convex portion at the time of contact with the photosensitive member.

JP 2007-199688 A JP 2012-103414 A

  As a charging member for charging a photoconductor having improved surface lubricity according to Patent Document 1, the present inventors relate to Patent Document 2 which is excellent in rotational stability during driven rotation with respect to the photoconductor. It was confirmed that the photoreceptor can be stably charged by using the charging member. However, when the present inventors made further studies on the combination of the photoreceptor according to Patent Document 1 and the charging member according to Patent Document 2, a new problem has been found. That is, when an electrophotographic image is formed using a process cartridge in which the photosensitive member according to Patent Document 1 and the charging member according to Patent Document 2 are in contact with each other, the electrophotographic image is periodically formed. In some cases, horizontal streak-like defects occurred.

  One embodiment of the present invention is a process cartridge and an electronic device capable of suppressing the generation of a rubbing memory when a charging member excellent in rotational stability during driven rotation with respect to a photosensitive member is used as a charging member for contact charging the photosensitive member. The present invention is directed to providing a photographic image forming apparatus.

According to one aspect of the present invention, there is provided a process cartridge that is detachable from a main body of an electrophotographic image forming apparatus,
An electrophotographic photoreceptor, and a charging member for charging the electrophotographic photoreceptor,
The electrophotographic photoreceptor is
A support, a charge generation layer, and a charge transport layer as a surface layer in this order,
The charge transport layer comprises
Including one or both of a polyarylate resin having a structure represented by the following formula (1) and a polycarbonate resin having a structure represented by the following formula (1),
The charging member is
It has a conductive substrate and a conductive resin layer as a surface layer in this order,
The conductive resin layer contains a binder and holds bowl-shaped resin particles having an opening in a state where the opening is exposed on the surface of the charging member,
The surface of the charging member is
A recess derived from the opening of the bowl-shaped resin particles exposed on the surface;
A convex portion derived from the edge of the opening of the bowl-shaped resin particles exposed on the surface;
An exposed portion of the conductive resin layer,
The bowl-shaped resin particles are:
Including at least one resin selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin and acrylic resin,
In the exposed portion of the conductive resin layer, a process cartridge containing silicone oil in a region from the surface to a depth of 50 nm is provided:

(In Formula (1), R ¹¹ and R ¹² each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. N represents the number of repetitions of the structure in parentheses. The average value of n is 10) It is 200 or less.)

According to another aspect of the present invention, there is provided an electrophotographic image forming apparatus comprising an electrophotographic photosensitive member and a charging member that charges the electrophotographic photosensitive member.
The electrophotographic photoreceptor has a support, a charge generation layer, and a charge transport layer as a surface layer in this order. The charge transport layer has a polyarylate resin having a structure represented by the formula (1). And any one or both of polycarbonate resins having a structure represented by the formula (1),
The charging member has a conductive base and a conductive resin layer as a surface layer in this order,
The conductive resin layer contains a binder and holds bowl-shaped resin particles having an opening in a state where the opening is exposed on the surface of the charging member,
The surface of the charging member has a concave portion derived from the opening of the bowl-shaped resin particles exposed on the surface, and a convex portion derived from the edge of the opening of the bowl-shaped resin particles exposed to the surface And an exposed portion of the conductive resin layer,
The bowl-shaped resin particles are:
Including at least one resin selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin and acrylic resin,
In the exposed portion of the conductive resin layer, an electrophotographic image forming apparatus containing silicone oil in a region from the surface to a depth of 50 nm is provided.

  According to one aspect of the present invention, a process cartridge capable of suppressing the generation of a rubbing memory when a charging member excellent in rotational stability at the time of driven rotation with respect to a photosensitive member is used as a charging member for contact charging the photosensitive member. In addition, an electrophotographic image forming apparatus can be obtained.

It is a schematic sectional drawing which shows an example of the charging member which concerns on this invention. FIG. 6 is an explanatory diagram showing a configuration in the vicinity of the surface of the charging member and a contact state with the photosensitive member according to the present invention. It is explanatory drawing which shows the contact state with the photoreceptor when receiving the vibration and impact in the physical distribution etc. of the surface vicinity of the charging member which concerns on this invention. It is a fragmentary sectional view near the surface of the charging member according to the present invention. It is a fragmentary sectional view near the surface of the charging member according to the present invention. It is explanatory drawing of the shape of the bowl-shaped resin particle used for this invention. It is explanatory drawing of the uneven distribution state of the silicone oil in the surface vicinity of the charging member which concerns on this invention. It is a schematic sectional drawing showing an example of the process cartridge which concerns on this invention. 1 is a schematic cross-sectional view illustrating an example of an electrophotographic image forming apparatus according to the present invention.

  When the process cartridge in which the photosensitive member according to Patent Document 1 and the charging member according to Patent Document 2 are in contact with each other is used for forming an electrophotographic image, the present inventors The reason why horizontal streak-like defects are generated was investigated. As a result, the process cartridge in which the charging member according to Patent Document 2 is in contact with the photosensitive member vibrates during distribution, so that the photosensitive member and the charging member are rubbed strongly. It was found that the formation of the electrostatic latent image was caused by the defect. The electrostatic latent image generated on the photoconductor due to the rubbing between the photoconductor and the charging member may be hereinafter referred to as “rubbing memory”. The rubbing memory is considered to be particularly likely to occur when a charging member according to Patent Document 2 having excellent rotational stability during driven rotation with respect to the photoreceptor is used.

  Based on such considerations, the present inventors have found that the sliding memory is excellent in that the photosensitive member has excellent grip properties and is less likely to slip even when driven and rotated with respect to a photosensitive member with high surface lubricity. In order to obtain a charging member that is less likely to cause the problem, studies were repeated. As a result, a conductive substrate and a conductive resin layer as a surface layer are provided in this order, and the conductive resin layer contains a binder and the bowl-shaped resin particles having the openings are formed in the openings. The surface of the charging member is held in an exposed state, and the surface of the charging member is exposed to the concave portion derived from the opening of the bowl-shaped resin particles exposed to the surface, and the surface is exposed to the surface. A convex portion derived from an edge of the opening of the bowl-shaped resin particles, and an exposed portion of the conductive resin layer, and the bowl-shaped resin particles are acrylonitrile resin, vinylidene chloride resin, methacrylonitrile. A charge containing at least one resin selected from the group consisting of a resin and an acrylic resin and containing silicone oil in the region from the surface to a depth of 50 nm in the exposed portion of the conductive resin layer Wood is excellent rotated with respect to surface lubricity highly photosensitive member and the rubbing memory is found that hardly causes the photoreceptor.

  The process cartridge according to one embodiment of the present invention will be described in detail below.

<Process cartridge>
The process cartridge according to the present invention includes a charging member and an electrophotographic photosensitive member charged by the charging member.
The charging member has a conductive base and a conductive resin layer as a surface layer in this order. The conductive resin layer contains a binder, and holds bowl-shaped resin particles having an opening in a state where the opening is exposed on the surface of the charging member, and the surface of the charging member is the surface. A concave portion derived from the opening of the bowl-shaped resin particles exposed to the surface, a convex portion derived from the edge of the opening of the bowl-shaped resin particles exposed to the surface, and an exposed portion of the conductive resin layer; Have The bowl-shaped resin particles include at least one resin selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin and acrylic resin, and in the exposed portion of the conductive resin layer, Silicone oil is contained in a region from the surface to a depth of 50 nm.
On the other hand, the electrophotographic photosensitive member has a support, a charge generation layer, and a charge transport layer in this order, and the charge transport layer as a surface layer has a polyarylate having a structure represented by the following formula (1) ( one or both of a (polylylate) resin and a polycarbonate resin having a structure represented by the following formula (1).

In formula (1), R ¹¹ and R ¹² each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. n represents the number of repetitions of the structure in parentheses. The average value of n is 10 or more and 200 or less.

The present inventors have described a mechanism that can suppress the generation of a rubbing memory when a process cartridge comprising a combination of the charging member and the photosensitive member uses a charging member having high driven rotation with respect to the photosensitive member as the charging member. The estimation is as follows.
FIG. 1 shows a circumferential cross section of a charging roller as an embodiment of a charging member according to the present invention. The charging roller shown in FIG. 1 (1 a) has a conductive substrate 1 and a conductive resin layer 2. Further, as shown in FIG. 1 (1b), the charging roller includes a conductive substrate 1, a conductive resin layer 21 as an intermediate layer on the conductive substrate 1, and a conductive layer as a surface layer on the intermediate layer. The structure which has the resin layer 22 may be sufficient. The conductive resin layer as the surface layer contains a binder. FIG. 2 shows a configuration in the vicinity of the surface of the charging member according to the present invention and a contact state with the photosensitive member. As shown in FIG. 2 (2a), the conductive resin layer as the surface layer holds the bowl-shaped resin particles 11 having openings in a state where the openings are exposed on the surface of the charging member. The surface of the charging member is also referred to as an exposed portion A1 of the conductive resin layer made of the binder 12 and a recess derived from the opening of the bowl-shaped resin particles 11 exposed on the surface (hereinafter simply referred to as “the bowl recess”). B1 and a convex portion (hereinafter simply referred to as “bowl convex portion”) C1 derived from the edge of the opening of the bowl-shaped resin particles 11 (hereinafter also simply referred to as “bowl edge”).

(Mechanism to suppress the generation of banding images)
As shown in FIG. 2 (2b), in the charging member having an uneven shape derived from the opening of the bowl-shaped resin particles exposed on the surface of the charging member, as shown in FIG. C1 contacts the photoconductor 15 while undergoing elastic deformation. On the other hand, when an electrophotographic image is formed, a voltage is applied to the charging member, so that the charging member charges the photoconductor by discharge in a minute gap with the photoconductor. This discharge is a so-called Townsend discharge that is generated when the air between the minute gaps is ionized. At that time, positive and negative charged particles generated by ionizing molecules in the air are induced on the surface of the photoreceptor or the charging member by an electric field formed between the minute gaps. Then, the charged particles are guided to the photoreceptor to charge the surface of the photoreceptor. Further, charged particles having a polarity opposite to that of the charged particles induced by the photosensitive member are also induced and charged on the charging member. The convex part of the bowl made of the above-mentioned thermoplastic resin is in a state of being charged up by the charge induced by the Townsend discharge on the surface of the charging member. At this time, since the convex portion of the bowl is made of a thermoplastic resin, the conductivity is low, and the charge-up state can be maintained for a long time. By this charge-up, an electric attractive force acts between the photosensitive member 15 and the convex portion C1 of the bowl, and the attractiveness between the charging member and the photosensitive member is increased. As described above, in the charging member according to the present invention, since an electrical attractive force acts between the photosensitive member and the convex portion of the bowl, the driven member can be rotated with respect to the photosensitive member, and the slip can be suppressed. As a result, it is estimated that the banding image is suppressed.

(Mechanism to suppress rubbing memory due to vibration and shock in logistics, etc.)
The charging member according to the present invention is usually in contact with the photosensitive member at the convex portion of the bowl, and has high driven rotation as described above. However, the convex portion of the bowl is made of resin and has elastic deformation. Therefore, as shown in FIG. 3 (3a), when strong vibration or strong impact in physical distribution or the like is applied in the X, Y, Z direction, the convex portion C1 of the bowl is There is a case where the exposed portion A1 of the conductive resin layer on the surface of the charging member and the surface of the photoreceptor 15 are rubbed due to deformation. At this time, when a conventional charging member is used, the charge moves to the exposed portion A1 of the conductive resin layer on the surface of the charging member due to friction between the photosensitive member surface and the exposed portion A1 of the conductive resin layer, and accumulates. Therefore, a horizontal streak-like image, so-called rubbing memory is generated. The movement of the charge is caused by frictional charging between the material used for the photoreceptor and the surface of the charging member.
On the other hand, the charging member according to the present invention contains silicone oil in the region from the surface of the exposed portion of the conductive resin layer to a depth of 50 nm, and the surface layer of the photoreceptor has the above formula (1). Any one or both of a polyarylate resin having a structure represented by the formula (1) and a polycarbonate resin having a structure represented by the above formula (1). By adopting such a configuration, the charged column between the exposed portion A1 of the conductive resin layer on the surface of the charging member and the surface of the photosensitive member becomes close, and frictional charging is hardly generated. As a result, it is presumed that the transfer of electric charges when the exposed portion of the conductive resin layer on the surface of the charging member and the surface of the photosensitive member are rubbed is suppressed, and the rub memory is suppressed. On the other hand, the high grip property with respect to the photoreceptor due to the deformation of the convex portion of the bowl is maintained. Therefore, it is possible to achieve both suppression of the banding image and suppression of the rubbing memory due to vibration and impact in physical distribution.

[Electrophotographic photoconductor]
The electrophotographic photosensitive member according to the present invention will be described in more detail. The electrophotographic photoreceptor according to the present invention has a support, a charge generation layer formed on the support, and a charge transport layer provided on the charge generation layer, and the charge transport layer is a surface. Is a layer. As the electrophotographic photosensitive member, generally, a cylindrical electrophotographic photosensitive member in which a photosensitive layer (charge generation layer, charge transport layer) is formed on a cylindrical support is widely used. It is also possible to have a sheet shape or the like.

[Support]
As the support, one having conductivity (conductive support) is preferable, and a metal support such as aluminum, aluminum alloy, and stainless steel can be used. In the case of a support made of aluminum or aluminum alloy, an ED tube (Extension Drawing), an EI tube (Extension Ironing), and these are cut and electrolytic combined polishing (electrolysis and polishing by an electrode having an electrolytic action and an electrolytic solution) Polishing with a grindstone), a wet or dry honing-treated support can also be used. Moreover, what formed the film by vacuum deposition of aluminum, an aluminum alloy, or an indium oxide tin oxide alloy on a metal support body or a resin support body can also be used. The surface of the support may be subjected to cutting treatment, roughening treatment, alumite treatment, or the like. Furthermore, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated in a resin, or a plastic having a conductive resin can also be used.

[Conductive layer]
A conductive layer may be provided between the support and an undercoat layer or charge generation layer described later for the purpose of suppressing interference fringes due to scattering of laser light or the like and covering the scratches on the support. The conductive layer is formed using a conductive layer coating liquid in which conductive particles are dispersed in a resin.
Examples of the conductive particles include carbon black, acetylene black, metal powder such as aluminum, nickel, iron, nichrome, copper, zinc, silver, and metal such as conductive tin oxide and ITO (indium tin oxide). Oxide powder is mentioned.
Examples of the resin used for the conductive layer include polyarylate resin, polycarbonate resin, polyvinyl butyral resin, acrylic resin, silicone resin, epoxy resin, melamine resin, urethane resin, phenol resin, and alkyd resin.
Examples of the solvent for the conductive layer coating solution include ether solvents, alcohol solvents, ketone solvents, and aromatic hydrocarbon solvents.
The thickness of the conductive layer is preferably 0.2 μm or more and 40 μm or less, preferably 1 μm or more and 35 μm or less, and more preferably 5 μm or more and 30 μm or less.

[Underlayer]
In the electrophotographic photosensitive member according to the present invention, an undercoat layer may be provided between the support or the conductive layer and the charge generation layer. The undercoat layer can be formed by applying a coating solution for an undercoat layer containing a resin on a support or a conductive layer, and drying or curing it.
Examples of the resin used for the undercoat layer include polyacrylic acids, methylcellulose, ethylcellulose, polyamide resin, polyimide resin, polyamideimide resin, polyamic acid resin, melamine resin, epoxy resin, polyurethane resin, and polyolefin resin.
The thickness of the undercoat layer is preferably 0.05 μm or more and 7 μm or less, and more preferably 0.1 μm or more and 2 μm or less. The undercoat layer may contain semiconductive particles, an electron transport material, or an electron accepting material.

[Charge generation layer]
A charge generation layer is provided on the support, the conductive layer, or the undercoat layer. The charge generation layer can be formed by applying a charge generation layer coating solution obtained by dispersing a charge generation material together with a resin and a solvent, and drying the obtained coating film. The charge generation layer may be a vapor generation film of a charge generation material. Examples of the dispersion method include a method using a homogenizer, an ultrasonic wave, a ball mill, a sand mill, an attritor, and a roll mill.
Examples of the charge generation material used in the charge generation layer include azo pigments, phthalocyanine pigments, indigo pigments, and perylene pigments. These charge generation materials may be used alone or in combination of two or more. Among these, metal phthalocyanines such as oxytitanium phthalocyanine, hydroxygallium phthalocyanine, and chlorogallium phthalocyanine are preferable because of their high sensitivity.

Examples of the resin used for the charge generation layer include polycarbonate resin, polyarylate resin, butyral resin, polyvinyl acetal resin, acrylic resin, vinyl acetate resin, and urea resin. Among these, a butyral resin is preferable. These may be used alone or in combination as a mixture or copolymer.
The ratio (mass ratio) between the charge generating material and the resin is preferably in the range of 1:10 to 10: 1, and more preferably in the range of 1: 1 to 3: 1.
Examples of the solvent used in the charge generation layer coating solution include alcohol solvents, sulfoxide solvents, ketone solvents, ether solvents, ester solvents, and aromatic hydrocarbon solvents.
The thickness of the charge generation layer is preferably from 0.01 μm to 5 μm, and more preferably from 0.1 μm to 2 μm.
In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary. Further, in order to prevent the flow of charges in the charge generation layer from stagnation, the charge generation layer may contain an electron transport material or an electron accepting material.

[Charge transport layer]
A charge transport layer is provided on the charge generation layer. In the electrophotographic photoreceptor according to the present invention, the charge transport layer is a surface layer.

(Polyarylate resin A, polycarbonate resin B)
In the present invention, the charge transport layer has a polyarylate resin A having a structure represented by the formula (1) (hereinafter also referred to as “polyarylate resin A”) and a structure represented by the formula (1). One or both of polycarbonate resin B (hereinafter also referred to as “polycarbonate resin B”).
In formula (1), R ¹¹ and R ¹² each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. Among these, R ¹¹ and R ¹² are preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group, and more preferably a methyl group or a phenyl group. n represents the number of repetitions of the structure in parentheses. The average value of n is 10 or more and 200 or less.

The content of the structure represented by the formula (1) in the polyarylate resin A and the polycarbonate resin B is preferably 5.0% by mass or more and 60% by mass or less, and preferably 10% by mass or more and 50% by mass or less. More preferably. By setting the content within the above range, it is possible to effectively suppress the transfer of charges between the members when the rubbing occurs between the photosensitive member and the charging member due to vibration or impact of physical distribution or the like. In addition, content of the structure represented by Formula (1) contained in the polyarylate resin A and the polycarbonate resin B can be calculated using a known method. For example, ¹ H-NMR measurement of the resin can be performed and confirmed by a conversion method using a peak area ratio of hydrogen atoms (hydrogen atoms constituting the resin).

  In the present invention, the abundance of silicon element on the outermost surface of the electrophotographic photoreceptor can be confirmed by measuring the abundance ratio of silicon element with respect to the constituent elements on the outermost surface. In the present invention, the abundance ratio of the silicon element to the constituent elements on the outermost surface of the surface layer (charge transport layer) of the electrophotographic photosensitive member measured using X-ray photoelectron for chemical analysis (ESCA) is , Preferably 3.0 atomic% or more, and more preferably 5.0 atomic% or more. In the case where the silicon element content is 3.0 atomic% or more, the above effect is more satisfactorily exhibited. Moreover, since the said effect is acquired more stably when the presence rate of a silicon element is 30 atomic% or less, it is preferable. That is, the abundance ratio of the silicon element is preferably 3.0 atomic percent or more and 30 atomic percent or less, and more preferably 5.0 atomic percent or more and 30 atomic percent or less.

In the present invention, the ratio of the silicon element to the constituent elements on the outermost surface of the surface layer of the electrophotographic photoreceptor by X-ray photoelectron spectroscopy (ESCA) is measured by PHI (Physical Electronics Industries, Inc.) Using a Quantum 2000 Scanning ESCA Microprobe, the following conditions were used. Then, the surface atomic concentration (atomic%) is calculated from the obtained peak intensity of each element using a relative sensitivity factor provided by PHI, and the silicon element is present in the constituent elements on the outermost surface of the surface layer.
Excitation X-ray: Al Kα
Photoelectron escape angle: 45 °
X-ray: 100μm 25W 15kV
Raster: 300μm × 200μm
Electron neutralizing gun: 20μA, 1V
Ion neutralizing gun: 7mA, 10V
Pass Energy: 58.70eV
Step Size: 0.125 eV
Sweep: F (10 times), C (10 times), O (10 times), Si (30 times), N (30 times)

  From the viewpoint that the effects of the present invention can be more easily obtained, the polyarylate resin A and the polycarbonate resin B include a polysiloxane structure represented by the following formula (15) as a structure represented by the above formula (1). Is preferred. This is because when the polyarylate resin A and the polycarbonate resin B have a polysiloxane structure represented by the formula (15), the polyarylate resin A and the polycarbonate resin B are likely to be localized on the outermost surface of the charge transport layer. This is probably because the amount of polysiloxane present on the surface is increased.

In formula (15), R ^{151 to} R ¹⁵⁴ each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{151 to} R ¹⁵⁴ are preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group, and preferably a methyl group or a phenyl group. Z represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Examples of the substituent for the alkyl group and aryl group include a halogen atom such as a fluorine atom. n represents the number of repetitions of the structure in parentheses. The average value of n is 10 or more and 200 or less.

  In the present invention, the polyarylate resin A or the polycarbonate resin B has a polysiloxane structure represented by the following formula (2) (hereinafter also referred to as “structure (2)”) at least at a part of the terminal. Is preferred. In the polyarylate resin A having the structure (2) at least at the terminal, the structural unit constituting the main chain to which the structure (2) is bonded is a structure represented by the formula (9) or (10) described later Units are listed. In the polycarbonate resin B having the structure (2) at least at a part of the terminal, the structural unit constituting the main chain to which the structure (2) is bonded is represented by the following formula (11) or (12). Examples include structural units.

Further, the polyarylate resin A is preferably a polyarylate resin having at least one of structural units represented by the following formulas (3) to (5). From the point that the effects of the present invention can be obtained more effectively, the polyarylate resin A is a polyarylate resin having a polysiloxane structure represented by the following formula (2) at least at a terminal, or the following formula (5) The polyarylate resin having a structural unit represented by
On the other hand, the polycarbonate resin B is preferably a polycarbonate resin having at least one of structural units represented by the following formulas (6) to (8). From the point that the effects of the present invention can be obtained more effectively, the polycarbonate resin B is a polycarbonate resin having a polysiloxane structure represented by the following formula (2) at least at a part of the terminals, or the following formula (8). A polycarbonate resin having a structural unit represented is more preferable.

  This is because polyarylate resin A and polycarbonate resin B having a polysiloxane structure represented by the formula (2) at least at a part of the terminals, and a polyarylate resin A having a structural unit represented by the formula (5) and The polycarbonate resin B having the structural unit represented by the formula (8) is easily localized on the outermost surface of the charge transport layer, and the polysiloxane structure in the resin localized on the outermost surface is directed to the outermost surface. This is probably because the amount of polysiloxane present on the outermost surface is further increased. In addition, the said polyarylate resin A and polycarbonate resin B may use only 1 type, and may use 2 or more types together. Below, the structure represented by Formula (2)-(8) is demonstrated in detail.

The structure represented by the formula (2) is a monovalent group.
In formula (2), R ^{21 to} R ²⁴ each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{21 to} R ²⁴ are preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group, and more preferably a methyl group or a phenyl group. Z shows a C1-C4 alkyl group or a phenyl group. m represents the number of repetitions of the structure in parentheses. The average value of m is 1 or more and 3 or less. n represents the number of repetitions of the structure in parentheses. Since the said effect can be expressed effectively, the average value of n is 10-200. Specific examples of the structure represented by formula (2) are shown below, but the present invention is not limited to these.

  The said structure may use only 1 type or may use 2 or more types together. Especially, the structure represented by Formula (2-1), (2-2), (2-5), (2-7), (2-11) or (2-13) is preferable.

In formula (3), R ^{31 to} R ³⁴ each independently represent a hydrogen atom, an alkyl group, a fluoroalkyl group, or a structure represented by the following formula (3-A). However, at least one of R ^{31 to} R ³⁴ has a structure represented by the following formula (3-A). Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{31 to} R ³⁴ are preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a group represented by the following formula (3-A), and may be a hydrogen atom, a methyl group, or the following formula (3-A). The group represented is more preferred. X ³ represents an m-phenylene group, a p-phenylene group, or a divalent group in which two p-phenylene groups are bonded via an oxygen atom. Y ³ represents a single bond, a methylene group, an ethylidene group, a propylidene group, or a phenylethylidene group. Specific examples of the structural unit represented by the formula (3) are shown below, but the present invention is not limited to these. In the formulas (3-1) to (3-14), A represents a structure represented by the following formula (3-A).

  The above structural units may be used alone or in combination of two or more. Among them, the formula (3-1), (3-2), (3-3), (3-4), (3-5), (3-6), (3-7) or (3-11) The structural unit represented by these is preferable.

In formula (3-A), R ^{311 to} R ³¹⁴ each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{311 to} R ³¹⁴ are preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group, and more preferably a methyl group. Z shows a C1-C4 alkyl group or a phenyl group. m represents the number of repetitions of the structure in parentheses. The average value of m is 0 or more and 5 or less. n represents the number of repetitions of the structure in parentheses. Since the said effect can be expressed effectively, the average value of n is 10-200. In addition, it is preferable that each value of the number of repetitions n of the structure in parentheses is within a range of ± 10% of the average value of n from the viewpoint of stably obtaining the effects of the present invention. Specific examples of the structure represented by the formula (3-A) are shown below, but the present invention is not limited to these.

  The said structure may use only 1 type or may use 2 or more types together. Among these, a structure represented by the formula (3-A-1), (3-A-2), (3-A-4) or (3-A-7) is preferable.

In formula (4), R ^{41 to} R ⁴⁴ each independently represent a hydrogen atom, an alkyl group, or a fluoroalkyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{41 to} R ⁴⁴ are preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or a methyl group. R ⁴⁵ represents a hydrogen atom, an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ⁴⁵ is preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and more preferably a hydrogen atom, a methyl group, or a phenyl group. V represents a structure represented by the following formula (4-A) or (4-B). X ⁴ represents an m-phenylene group, a p-phenylene group, or a divalent group in which two p-phenylene groups are bonded via an oxygen atom. Specific examples of the structural unit represented by formula (4) are shown below, but the present invention is not limited thereto. In the formulas (4-1) to (4-12), V represents a structure represented by the following formula (4-A) or (4-B).

  The above structural units may be used alone or in combination of two or more. Among these, structural units represented by the formulas (4-1), (4-2), (4-3), (4-4), (4-5) or (4-6) are preferable.

In formula (4-A), R ^{411 to} R ⁴¹⁴ each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{411 to} R ⁴¹⁴ are preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group. Z shows a C1-C4 alkyl group or a phenyl group. m represents the number of repetitions of the structure in parentheses. In order to sufficiently exhibit the effects of the present invention, the average value of m is 3 or more and 20 or less. Moreover, it is preferable that the difference between the maximum value and the minimum value of the number of repetitions m of the structure in parentheses is 0 or more and 3 or less from the viewpoint that the effect of the present invention can be stably obtained. n represents the number of repetitions of the structure in parentheses. Since the said effect can be expressed effectively, the average value of n is 10-200. Furthermore, the average value of n is preferably 10 or more and 100 or less. In addition, it is preferable that each value of the number of repetitions n of the structure in parentheses is within a range of ± 10% of the average value of n from the viewpoint of stably obtaining the effects of the present invention.

In formula (4-B), R ^{421 to} R ⁴²⁸ each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{421 to} R ⁴²⁸ are preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group. Z ¹ and Z ² each independently represent an alkyl group having 1 to 4 carbon atoms or a phenyl group. m represents the number of repetitions of the structure in parentheses. In order to sufficiently exhibit the effects of the present invention, the average value of m is 3 or more and 20 or less. Moreover, it is preferable that the difference between the maximum value and the minimum value of the number of repetitions m of the structure in parentheses is 0 or more and 3 or less from the viewpoint that the effect of the present invention can be stably obtained. n ¹ and n ² indicate the number of repetitions of the structure in parentheses. In order to sufficiently exhibit the effects of the present invention, the average value of n ^{1 and} the average value of n ² are each independently 10 or more and 200 or less, and the sum of the average value of n ^{1 and} the average value of n ² The value is 20 or more and 250 or less. Furthermore, the average value and the average value of ^{n 2} of ^{n 1} are each independently is preferably 10 or more and 100 or less. In addition, the individual values of the number of repetitions n ¹ and n ² of the structure in parentheses are within the range of ± 10% of the average value of n ^{1 and} the average value of n ² , respectively. It is preferable at the point obtained stably.

In formula (5), W represents a structure represented by the following formula (5-A). X ⁵ represents an m-phenylene group, a p-phenylene group, or a divalent group in which two p-phenylene groups are bonded via an oxygen atom. m ¹ and m ² represent the number of repetitions of the structure in parentheses. The average value of m ^{1 and} the average value of m ² are each independently 1 or more and 3 or less. Specific examples of the structural unit represented by formula (5) are shown below, but the present invention is not limited thereto. In the formulas (5-1) to (5-6), W represents a structure represented by the following formula (5-A).

  The above structural units may be used alone or in combination of two or more. Among these, the structural unit represented by the formula (5-1), (5-2), or (5-3) is preferable.

In formula (5-A), R ^{511 to} R ⁵²⁰ each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{511 to} R ⁵²⁰ are preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group. Z shows a C1-C4 alkyl group or a phenyl group. k and l indicate the number of repetitions of the structure in parentheses. The average value of k and the average value of l are each independently 1 or more and 10 or less. In addition, the difference between the maximum value and the minimum value of the number of repetitions k and l of the structure in parentheses is preferably 0 or more and 3 or less. n represents the number of repetitions of the structure in parentheses. The average value of n is 10 or more and 200 or less. In order to sufficiently exhibit the effect of the present case, the average value of n is preferably 10 or more and 150 or less. In addition, it is preferable that each value of the number of repetitions n of the structure in parentheses is within a range of ± 10% of the average value of n from the viewpoint of stably obtaining the effects of the present invention.

In formula (6), R ^{61 to} R ⁶⁴ each independently represent a hydrogen atom, an alkyl group, a fluoroalkyl group, a phenyl group, or a structure represented by the following formula (6-A). However, at least one of R ^{61 to} R ⁶⁴ has a structure represented by the following formula (6-A). Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{61 to} R ⁶⁴ are preferably a hydrogen atom or a structure represented by the following formula (6-A). Y ⁶ represents a single bond, a methylene group, an ethylidene group, a propylidene group, a phenylethylidene group, a cyclohexylidene group, or an oxygen atom. Specific examples of the structural unit represented by formula (6) are shown below, but the present invention is not limited thereto. In the formulas (6-1) to (6-9), A represents a structure represented by the following formula (6-A).

  The above structural units may be used alone or in combination of two or more. Among these, a structural unit represented by the formula (6-1), (6-3), (6-5), (6-6) or (6-8) is preferable.

In formula (6-A), R ^{611 to} R ⁶¹⁴ each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{611 to} R ⁶¹⁴ are preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group, and more preferably a methyl group. Z shows a C1-C4 alkyl group or a phenyl group. m represents the number of repetitions of the structure in parentheses. The average value of m is 0 or more and 5 or less. n represents the number of repetitions of the structure in parentheses. The average value of n is 10 or more and 200 or less. In addition, it is preferable that each value of the number of repetitions n of the structure in parentheses is within a range of ± 10% of the average value of n from the viewpoint of stably obtaining the effects of the present invention.
Specific examples of the structure represented by the formula (6-A) include the same ones as the formulas (3-A-1) to (3-A-9). However, the present invention is not limited to these. Moreover, the said structure may use only 1 type, or may use 2 or more types together.

Wherein ^{(7), R} 71 ~R ⁷⁴ each independently represent a hydrogen atom, an alkyl group, fluoroalkyl group or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{71 to} R ⁷⁴ are preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. R ⁷⁵ represents a hydrogen atom, an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ⁷⁵ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom or a methyl group. V represents a structure represented by the following formula (7-A) or (7-B). Although the specific example of the structural unit represented by Formula (7) below is shown, it is not restricted to these. In the formulas (7-1) to (7-4), V represents a structure represented by the following formula (7-A) or (7-B).

  The above structural units may be used alone or in combination of two or more. Among these, the structural unit represented by the formula (7-1) or (7-2) is preferable.

In formula (7-A), R ^{711 to} R ⁷¹⁴ each independently represent an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{711 to} R ⁷¹⁴ are preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group. Z shows a C1-C4 alkyl group or a phenyl group. m represents the number of repetitions of the structure in parentheses. The average value of m is 3 or more and 20 or less. Moreover, it is preferable that the difference between the maximum value and the minimum value of the number of repetitions m of the structure in parentheses is 0 or more and 3 or less from the viewpoint that the effect of the present invention can be stably obtained. n represents the number of repetitions of the structure in parentheses. The average value of n is 10 or more and 200 or less. Furthermore, the average value of n is preferably 10 or more and 100 or less. In addition, it is preferable that each value of the number of repetitions n of the structure in parentheses is within a range of ± 10% of the average value of n from the viewpoint of stably obtaining the effects of the present invention.

In formula (7-B), R ^{721 to} R ⁷²⁸ each independently represent an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{721 to} R ⁷²⁸ are preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group. Z ¹ and Z ² each independently represent an alkyl group having 1 to 4 carbon atoms or a phenyl group. m represents the number of repetitions of the structure in parentheses. The average value of m is 3 or more and 20 or less. Moreover, it is preferable that the difference between the maximum value and the minimum value of the number of repetitions m of the structure in parentheses is 0 or more and 3 or less from the viewpoint that the effect of the present invention can be stably obtained. n ¹ and n ² indicate the number of repetitions of the structure in parentheses. The average value of n ^{1 and} the average value of n ² are each independently 10 or more and 200 or less, and the total value of the average value of n ^{1 and} the average value of n ² is 20 or more and 250 or less. Furthermore, the average value and the average value of ^{n 2} of ^{n 1} are each independently is preferably 10 or more and 100 or less. In addition, the individual values of the number of repetitions n ¹ and n ² of the structure in parentheses are within the range of ± 10% of the average value of n ^{1 and} the average value of n ² , respectively. It is preferable at the point obtained stably.

In formula (8), W represents a structure represented by the following formula (8-A). m ¹ and m ² represent the number of repetitions of the structure in parentheses. The average value of m ^{1 and} the average value of m ² are each independently 1 or more and 3 or less. Specific examples of the structural unit represented by formula (8) are shown below, but the present invention is not limited to these. In the formulas (8-1) and (8-2), W represents a structure represented by the following formula (8-A).

  Moreover, said structural unit may use only 1 type, or may use 2 or more types together. Among these, the structural unit represented by the formula (8-1) is preferable.

In formula (8-A), R ^{811 to} R ⁸²⁰ each independently represent an alkyl group, a fluoroalkyl group, or a phenyl group. Examples of the alkyl group and the fluoroalkyl group include an alkyl group having 1 to 4 carbon atoms and a fluoroalkyl group having 1 to 4 carbon atoms. R ^{811 to} R ⁸²⁰ are preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group. Z shows a C1-C4 alkyl group or a phenyl group. k and l indicate the number of repetitions of the structure in parentheses. The average value of k and the average value of l are each independently 1 or more and 10 or less. In addition, the difference between the maximum value and the minimum value of the number of repetitions k and l of the structure in parentheses is preferably 0 or more and 3 or less. n represents the number of repetitions of the structure in parentheses. The average value of n is 10 or more and 200 or less. Furthermore, the average value of n is preferably 10 or more and 150 or less. In addition, it is preferable that each value of the number of repetitions n of the structure in parentheses is within a range of ± 10% of the average value of n from the viewpoint of stably obtaining the effects of the present invention.

  In the present invention, the polyarylate resin A and the polycarbonate resin B may have other structural units other than the structural units represented by the formulas (3) to (8) on the main chain skeleton. In that case, as for another structural unit, only 1 type may be used or 2 or more types may be used together. As structural units other than the structural units represented by the formulas (3) to (8), structural units represented by the following formulas (9) to (12) are preferable.

In formula (9), R ^{91 to} R ⁹⁸ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Examples of the substituent for the alkyl group and aryl group include a halogen atom such as a fluorine atom. R ^{91 to} R ⁹⁸ are preferably a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or a methyl group. X ⁹ represents an m-phenylene group, a p-phenylene group, or a divalent group in which two p-phenylene groups are bonded via an oxygen atom. Y ⁹ represents a single bond, an oxygen atom, a sulfur atom, or a divalent organic group. Y ⁹ is preferably a single bond or a divalent organic group having 1 to 3 carbon atoms.

In formula (10), R ^{101 to} R ¹⁰⁴ each independently represent a methyl group, an ethyl group, or a phenyl group. X ¹⁰ represents an m-phenylene group, a p-phenylene group, or a divalent group in which two p-phenylene groups are bonded via an oxygen atom. n represents the number of repetitions of the structure in parentheses. The average value of n is preferably 10 or more and 150 or less.

In formula (11), R ^{111 to} R ¹¹⁸ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Examples of the substituent for the alkyl group and aryl group include a halogen atom such as a fluorine atom. R ^{111 to} R ¹¹⁸ are preferably a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom or a methyl group. Y ¹¹ represents a single bond, an oxygen atom, a sulfur atom, or a divalent organic group. Y ¹¹ is preferably a single bond, an oxygen atom, a divalent organic group having 1 to 3 carbon atoms (a methylene group, an ethylidene group, or a propylidene group), a phenylethylidene group, or a cyclohexylidene group.

In formula (12), R ^{121 to} R ¹²⁴ each independently represents a methyl group, an ethyl group, or a phenyl group. n represents the number of repetitions of the structure in parentheses. The average value of n is preferably 10 or more and 150 or less.

  Specific examples of the structural units represented by the formulas (9) to (12) are shown below, but the present invention is not limited to these.

  As described above, the polyarylate resin A and the polycarbonate resin B preferably have a polysiloxane structure represented by the formula (15) as the structure represented by the formula (1). Moreover, the polyarylate resin A and the polycarbonate resin B may contain a linear polysiloxane structure in the main chain skeleton instead of the polysiloxane structure represented by the formula (15). Specifically, the main chain skeleton containing a linear polysiloxane structure is represented by a polyarylate resin having a structural unit represented by the formula (10) and the formula (12). A polycarbonate resin having a structural unit may be mentioned. Especially, the polyarylate resin which has a structural unit represented by said Formula (10-1)-(10-3), or the polycarbonate resin which has a structural unit represented by said Formula (12-1) is preferable. These structural units may be used alone or in combination of two or more.

  The viscosity average molecular weight (Mv) of the polyarylate resin A and the polycarbonate resin B is preferably 1,000 or more and 200,000 or less. Further, from the viewpoints of synthesis and film formability, the viscosity average molecular weight (Mv) is more preferably 5,000 or more and 100,000 or less. The polyarylate resin A and the polycarbonate resin B can be synthesized by appropriately selecting from known methods such as transesterification, interfacial polymerization, and direct polymerization.

(Other resins)
In the present invention, the charge transport layer which is the surface layer of the electrophotographic photosensitive member includes a polyarylate resin A having a structure represented by the formula (1) and a polycarbonate having a structure represented by the formula (1). Although at least one resin selected from the group consisting of the resin B is contained, other resins than the polyarylate resin A and the polycarbonate resin B may be used in combination as long as the effects of the present invention are not impaired. In that case, the total content of the polyarylate resin A and the polycarbonate resin B in the charge transport layer is 0.1% by mass or more and 50% by mass or less with respect to the total mass of the total solid content contained in the charge transport layer. Thus, it is preferable to use other resins. In addition, when the polyarylate resin A and the polycarbonate resin B have a polysiloxane structure represented by the formula (2) at least at a part of the terminals, the charge transport layer can be obtained because good electrical characteristics of the photoreceptor can be obtained. The total content of the polyarylate resin A and the polycarbonate resin B in is preferably 0.1% by mass or more and 20% by mass or less with respect to the total mass of the total solid content contained in the charge transport layer.

  Examples of other resins that can be used in combination include acrylic resin, acrylonitrile resin, allyl resin, alkyd resin, epoxy resin, silicone resin, phenol resin, phenoxy resin, butyral resin, polyacrylamide resin, polyacetal resin, polyamideimide resin, polyamide Resin, polyallyl ether resin, polyarylate resin, polyimide resin, polyurethane resin, polyester resin, polyethylene resin, polycarbonate resin, polystyrene resin, polysulfone resin, polyvinyl butyral resin, polyphenylene oxide resin, polybutadiene resin, polypropylene resin, methacrylic resin, urea Resin, vinyl chloride resin, vinyl acetate resin, etc. are mentioned. Among these, polyester resins, polyarylate resins, and polycarbonate resins are preferable. Furthermore, a polyarylate resin having a structural unit represented by the formula (9) or a polycarbonate resin having a structural unit represented by the formula (11) is more preferable. Specific examples of the structural unit represented by the formula (9) and the structural unit represented by the formula (11) are as described above. As the other resins that can be used in combination with the polyarylate resin A or the polycarbonate resin B, one or more kinds can be used alone, as a mixture, or as a copolymer.

  In the electrophotographic photoreceptor of the present invention, it is preferable to add polydimethylsiloxane represented by the following formula (16) in addition to one or both of the polyarylate resin A and the polycarbonate resin B. By further mixing polydimethylsiloxane represented by the following formula (16), the abundance ratio of the polysiloxane structure on the outermost surface of the electrophotographic photosensitive member is further increased, and charge is transferred between the photosensitive member and the charging member during rubbing. Can be suppressed.

In formula (16), n represents the number of repetitions of the structure in parentheses. The average value of n is 10 or more and 200 or less.
The addition amount of the polydimethylsiloxane represented by the formula (16) is 3.0% by mass or more and 20.0% by mass or less with respect to the polyarylate resin A and the polycarbonate resin B contained in the charge transport layer. Is preferred. The said effect can be effectively expressed by making the addition amount of polydimethylsiloxane into the said range. Moreover, it is preferable that n in Formula (16) is 10 or more and 100 or less. When polydimethylsiloxane is added alone, the residual potential is remarkably increased even with a small amount of addition, and a memory image such as a decrease in image density and a ghost due to a decrease in sensitivity is likely to occur. However, when one or both of the polyarylate resin A and polycarbonate resin B according to the present invention and polydimethylsiloxane are mixed in the above range, the residual potential is hardly increased and good image quality can be obtained.

(Charge transport material)
The charge transport layer contains a charge transport material. Examples of the charge transport material include triarylamine compounds, hydrazone compounds, styryl compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, stilbene compounds, butadiene compounds, and enamine compounds. These charge transport materials may be used alone or in combination of two or more. Specific examples of the charge transport material are shown below, but the present invention is not limited to these.

(Method for forming charge transport layer)
The charge transport layer can be formed by one or both of the polyarylate resin A and the polycarbonate resin B, and a coating film of a coating solution for charge transport layer obtained by dissolving a charge transport material in a solvent. Further, as described above, other resins than the polyarylate resin A and the polycarbonate resin B may be used in combination. The charge transport layer may have a laminated structure. In that case, at least one of or both of the polyarylate resin A and the polycarbonate resin B is contained in the charge transport layer on the most surface side.
The ratio (mass ratio) between the charge transport material and the total resin in the charge transport layer is preferably in the range of 3:10 to 20:10, and more preferably in the range of 5:10 to 12:10. .
Examples of the solvent used in the charge transport layer coating solution include ketone solvents, ester solvents, ether solvents, and aromatic hydrocarbon solvents. These solvents may be used alone or in combination of two or more. Among these solvents, it is preferable to use an ether solvent or an aromatic hydrocarbon solvent from the viewpoint of the solubility of the resin.
The film thickness of the charge transport layer is preferably 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 35 μm or less.

Various additives can be added to each layer of the electrophotographic photoreceptor described above. Examples of the additive include deterioration inhibitors such as antioxidants, ultraviolet absorbers, and light stabilizers, and particles such as organic particles and inorganic particles. Examples of the deterioration inhibitor include hindered phenol antioxidants, hindered amine light resistance stabilizers, sulfur atom-containing antioxidants, and phosphorus atom-containing antioxidants. Examples of the organic particles include polymer resin particles such as fluorine atom-containing resin particles, polystyrene resin particles, and polyethylene resin particles. Examples of the inorganic particles include metal oxide particles such as silica and alumina.
When applying the coating liquid for each of the above layers, a coating method such as a dip coating method (dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, or a blade coating method can be used. .

(Charging member)
The charging member according to the present invention has a conductive substrate 1 and a conductive resin layer 2 as shown in FIG. As shown in FIG. 1 (1b), the conductive resin layer may have a two-layer structure including a conductive resin layer 21 (intermediate layer) and 22 (surface layer). The conductive resin layer contains a binder and bowl-shaped resin particles.
The conductive substrate 1 and the conductive resin layer 2 or the layers sequentially laminated on the conductive substrate 1 (for example, the conductive resin layer 21 and the conductive resin layer 22 shown in FIG. 1 (1b)) are made of an adhesive. You may adhere through. In this case, the adhesive is preferably conductive. A known adhesive can be used as the conductive adhesive. Examples of the base of the adhesive include thermosetting resins and thermoplastic resins, and known ones such as urethane, acrylic, polyester, polyether, and epoxy can be used. As a conductive agent for imparting conductivity to the adhesive, one selected from conductive fine particles described in detail later can be used alone, or two or more can be used in combination.

[Conductive substrate]
The conductive substrate used in the charging member of the present invention has conductivity and has a function of supporting a conductive resin layer provided on the conductive substrate. Examples of the material include metals such as iron, copper, aluminum and nickel and alloys thereof (stainless steel, etc.).

[Conductive resin layer]
(Bowl-shaped resin particles)
In the present invention, the bowl-shaped resin particles include at least one resin selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin, and acrylic resin.

FIG. 4 is a partial cross-sectional view of the vicinity of the surface of the conductive resin layer 42 constituting the surface layer of the charging member according to the present invention. Bowl-shaped resin particles 41 contained in the conductive resin layer are exposed on the surface of the charging member. The surface of the charging member has a concave portion 52 derived from the opening 51 of the bowl-shaped resin particles exposed on the surface and a convex portion derived from the edge 53 of the opening of the bowl-shaped resin particles exposed on the surface. And have. The edge 53 can take the form shown in (4a) and (4b) of FIG.
The height difference 54 between the apex of the convex portion derived from the edge 53 of the opening of the bowl-shaped resin particle and the bottom of the concave portion 52 defined by the shell of the bowl-shaped resin particle shown in FIG. 5 is 5 μm or more. It is preferably 100 μm or less, and more preferably 10 μm or more and 80 μm or less. By setting the height difference 54 within the above range, the point contact of the edge of the bowl in the nip portion can be more reliably maintained, and the effect of suppressing the banding image can be sufficiently exhibited. Further, the ratio of the height difference 54 between the top of the convex part and the bottom part of the concave part and the maximum diameter 55 of the bowl-shaped resin particles, that is, [maximum diameter] / [height difference] of the resin particles is 0. It is preferably 8 or more and 3.0 or less. By setting the [maximum diameter] / [height difference] of the resin particles within the above range, the point contact of the edge of the bowl at the nip portion can be more reliably maintained, and the effect of suppressing the banding image can be sufficiently exhibited. it can.

  Moreover, it is preferable that the surface state of the conductive resin layer is controlled as follows by the formation of the uneven shape. The ten-point average surface roughness (Rzjis) is preferably 5 μm or more and 65 μm or less, and more preferably 10 μm or more and 50 μm or less. The average irregularity (Sm) on the surface is preferably 30 μm or more and 200 μm or less, and more preferably 40 μm or more and 150 μm or less. By setting the surface state of the conductive resin layer within the above range, it is possible to more reliably maintain the point contact of the edge of the bowl in the nip portion and sufficiently exhibit the effect of suppressing the banding image. The method for measuring the surface ten-point average roughness (Rzjis) and the surface unevenness average interval (Sm) will be described in detail in Examples.

An example of bowl-shaped resin particles used in the present invention is shown in (6a) to (6e) of FIG. In the present invention, the “bowl shape” refers to a shape having an opening 61 and a recess 62 having a rounded opening. As shown in (6a) and (6b) of FIG. 6, the “opening” may have a flat edge of the bowl, and as shown in (6c) to (6e) of FIG. The edge may have unevenness.
The standard of the maximum diameter 55 of the bowl-shaped resin particles is 10 μm or more and 150 μm or less, and preferably 20 μm or more and 100 μm or less. The ratio between the maximum diameter 55 of the bowl-shaped resin particles and the minimum diameter 63 of the opening, that is, the [maximum diameter] / [minimum diameter of the opening] of the bowl-shaped resin particles is 1.1 or more. It is preferably 0 or less.
The thickness of the shell around the opening of the bowl-shaped resin particles (the difference between the outer diameter and the inner diameter of the edge) is preferably 0.1 μm or more and 3 μm or less, and more preferably 0.2 μm or more and 2 μm or less. In addition, the “maximum thickness” of the shell is preferably 3 times or less of the “minimum thickness”, more preferably 2 times or less.

(binder)
As the binder contained in the conductive resin layer, the following are preferable from the viewpoints of resistance adjustment, hardness control and deformation-restoration control for achieving nip formation with the photoreceptor and suppression of banding images. Used for. Styrene butadiene rubber (SBR), butyl rubber, acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), butadiene rubber (BR). When a material having a low affinity for silicone oil is used as the binder, the silicone oil described later can be better transferred to the outer surface side. Accordingly, among the materials described above, styrene butadiene rubber, butyl rubber, and acrylonitrile butadiene rubber are particularly preferably used.

(Silicone oil)
In addition, as described above, the conductive resin layer of the charging member contains silicone oil in a region from the surface of the exposed portion to 50 nm in order to suppress frictional memory. By containing silicone oil in the region, even when the conductive resin layer is deformed during friction with the electrophotographic photosensitive member, the effect of suppressing the friction memory can be sufficiently exerted. It is preferable that the silicone oil is unevenly distributed on the outermost surface in direct contact with the electrophotographic photosensitive member. By setting it as such a state, the effect of memory friction suppression can be exhibited more reliably. The presence state of the silicone oil on the surface of the conductive resin layer can be confirmed by measuring the existing ratio of the silicon element to the constituent elements on the surface. In the present invention, the abundance ratio of the silicon element to the constituent element on the outermost surface of the conductive resin layer is measured using X-ray photoelectron spectroscopy (ESCA). The silicon element content in the outermost surface of the conductive resin layer is preferably 0.65 atomic% or more, and more preferably 1.0 atomic% or more. By making the abundance ratio of the silicon element within the above range, the effect of suppressing the rubbing memory can be surely exhibited. The abundance ratio of the silicon element is preferably 20 atomic% or less, more preferably 16 atomic% or less, and more preferably 10 atomic% or less from the viewpoint of driven rotation with the electrophotographic photosensitive member. More preferably.

In the present invention, the measurement of the abundance ratio of silicon element to the constituent elements on the outermost surface of the conductive resin layer by X-ray photoelectron spectroscopy (ESCA) is performed under the following conditions using PHI Quantera SXM manufactured by ULVAC-PHI. went. Then, the surface atomic concentration (atomic%) is calculated from the obtained peak intensity of each element by using a relative sensitivity factor provided by PHI, and the silicon element is present in the constituent elements on the surface of the conductive resin layer. .
Excitation X-ray: Al Kα
Photoelectron escape angle: 45 °
X-ray: 100μm 25W 15kV
Raster: 400μm × 400μm
Pass Energy: 112eV
Step Size: 0.2eV
Sweep: C (20 times), O (20 times), Si (10 times), N (5 times), S (20 times), Ca (20 times), Zn (20 times)

  In addition, the presence ratio of the silicone oil in the depth direction of the conductive resin layer was measured by etching the conductive resin layer by Ar ion sputtering and performing elemental analysis by the above method every time the target depth was reached. The sputtering conditions were performed using an Ar ion sputtering apparatus attached to the above apparatus at an acceleration voltage of 2 kV and a sputtering area of 2 mm × 2 mm.

A known silicone oil can be used as the type of silicone oil. From the viewpoint of ease of migration to the surface of the conductive resin layer, dimethylpolysiloxane is preferable, and linear dimethylpolysiloxane is more preferable. Further, the amount of silicone oil added is preferably 0.2 parts or more and 2.0 parts or less, and more preferably 0.4 parts or more and 1.0 parts or less with respect to 100 parts of the binder. By making the addition amount of the silicone oil within the above range, it is possible to sufficiently exhibit the effect of suppressing the rubbing memory and to stably take in the silicone oil into the binder and maintain the workability. Furthermore, the viscosity of the silicone oil at room temperature (25 ° C.) is preferably 10 mm ² / s or more and 200 mm ² / s or less, and more preferably 30 mm ² / s or more and 100 mm ² / s or less. By setting the viscosity within the above range, vaporization of silicone oil due to heat can be suppressed, and transferability to the surface can be enhanced. As a result, silicone oil can be unevenly distributed on the outermost surface of the conductive resin layer, and the effect of suppressing the rubbing memory can be surely exhibited.

The volume resistivity of the conductive resin layer, temperature 23 ° C., under a relative humidity of 50%, 1 × 10 ² [Omega] cm or more, 1 × is preferably ^{10 16} [Omega] cm or less, 1 × 10 ² [Omega] cm or more, 1 × and more preferably ^{10 10} [Omega] cm or less. If the volume resistivity is within the above range, it becomes easier to appropriately charge the photoreceptor by discharging. At the same time, the generation of banding images can be more reliably suppressed. From the viewpoint of controlling the volume resistivity of the conductive resin layer within the above range, the silicone oil 73 contained in the conductive resin layer 72 has a surface as shown in FIG. 7 (7b) in the cross-sectional direction of the charging member. It is preferable that it is unevenly distributed to the side. With such a configuration, it becomes easy to control the volume resistivity of the conductive resin layer to a more preferable range, and the generation of banding images can be more reliably suppressed.

(Conductive fine particles)
In order to control the volume resistivity of the conductive resin layer within the above range, known conductive fine particles may be contained in the conductive resin layer. Examples of the conductive fine particles include fine particles of metal oxide, metal, carbon black, and graphite. These conductive fine particles can be used singly or in combination of two or more. The content of the conductive fine particles in the conductive resin layer is preferably 2 to 200 parts by mass and more preferably 5 to 100 parts by mass with respect to 100 parts by mass of the binder.

[Method for forming conductive resin layer]
A method for forming the conductive resin layer is exemplified below. First, a coating layer of a composition in which hollow resin particles are dispersed in a binder is formed on a conductive substrate. Then, by polishing the surface of the coating layer, a part of the shell of the hollow resin particles is removed to form a bowl shape having an opening, and a recess formed by the opening of the bowl-shaped resin particle and the bowl-shaped resin Convex portions are formed by the edges of the opening of the particles (hereinafter, the shape including these irregularities is referred to as “concave shape by opening of bowl-shaped resin particles”). Next, the conductivity of the material present on the surface of the coating layer is adjusted by applying conductive fine particles to the recesses, or by heat treatment of the coating layer in an oxygen-containing atmosphere.
Hereinafter, each process of the formation method of a conductive resin layer is demonstrated in detail. Of the coating layers, the coating layer before the polishing step is referred to as a “preliminary coating layer”. In addition, the “hollow resin particle shell” in the raw material of the charging member is referred to as “bowl-shaped resin particle bowl” in the charging member in which the bowl-shaped resin particles having openings are formed by the polishing process. .

(Dispersion of resin particles in pre-coating layer)
First, a method for dispersing hollow resin particles in the preliminary coating layer will be described. As a first method, a coating film of a conductive resin composition in which hollow resin particles containing a gas inside are dispersed in a binder is formed on a conductive substrate, and the coating film is dried and cured. Or a method of performing crosslinking or the like. In addition, conductive particles can be contained in the conductive resin composition. As a material used for the hollow resin particles, at least one resin selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin and acrylic resin is used. Among these, from the viewpoint of low gas permeability and high resilience, a resin having a polar group is preferable, and a resin having a unit represented by the following formula (4) is more preferable. Further, from the viewpoint of easy control of the polishing property, a resin having both a unit represented by the following formula (4) and a unit represented by the following formula (8) is more preferable.

  In formula (4), R1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. A is at least one selected from the group consisting of the following formulas (5), (6) and (7). In the following formula (8), R2 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R3 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

  As the second method, a method using a thermally expandable microcapsule that includes an encapsulated substance inside the particle and expands the encapsulated substance by applying heat to form hollow resin particles can be exemplified. . Specifically, a method of producing a conductive resin composition in which thermally expandable microcapsules are dispersed in a binder, coating the composition on a conductive substrate, and drying, curing, crosslinking, or the like It is. According to this method, the encapsulated substance can be expanded by heat at the time of drying, curing, or crosslinking of the binder used for the preliminary coating layer to form hollow resin particles. At that time, the particle size can be controlled by controlling the temperature condition.

  When using a thermally expandable microcapsule, it is necessary to use a thermoplastic resin as the material of the thermally expandable microcapsule. As the thermoplastic resin, a material having low gas permeability and high resilience is selected from the viewpoint of contact stability with respect to the photoreceptor. Further, as will be described later, it is preferable to select a material having low gas permeability in order to contain silicone oil in the binder portion on the surface of the charging member. In the present invention, a thermoplastic resin composed of at least one selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin, and acrylic resin is used. These thermoplastic resins can be used individually by 1 type or in combination of 2 or more types. Furthermore, these thermoplastic resin monomers may be copolymerized to form a copolymer.

  As the substance (encapsulated substance) to be encapsulated in the heat-expandable microcapsule, those that vaporize and expand at a temperature below the softening point of the thermoplastic resin are preferable, and examples thereof include the following. Low boiling liquids such as propane, propylene, butene, normal butane, isobutane, normal pentane, and isopentane, and high boiling liquids such as normal hexane, isohexane, normal heptane, normal octane, isooctane, normal decane, and isodecane.

  The thermally expandable microcapsule can be produced by a known production method such as a suspension polymerization method, an interfacial polymerization method, an interfacial precipitation method, or a submerged drying method. For example, in the suspension polymerization method, a polymerizable monomer, an inclusion substance, and a polymerization initiator are mixed, and the obtained mixture is dispersed in an aqueous medium containing a surfactant and a dispersion stabilizer. A method for suspension polymerization can be exemplified. A compound having a reactive group that reacts with a functional group of the polymerizable monomer or an organic filler can also be added.

  The following can be illustrated as a polymerizable monomer. Acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, fumaronitrile, acrylic acid, methacrylic acid, vinylidene chloride, acrylic acid ester (methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, Isobornyl acrylate, cyclohexyl acrylate, benzyl acrylate), methacrylic acid esters (methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, isobornyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate). These polymerizable monomers can be used individually by 1 type or in combination of 2 or more types.

  Although it does not specifically limit as a polymerization initiator, The initiator soluble in a polymerizable monomer is preferable, and a well-known peroxide initiator and an azo initiator can be used. An example of the peroxide initiator is dicumyl peroxide. Examples of the azo initiator include 2,2′-azobisisobutyronitrile, 1,1′-azobiscyclohexane 1-carbonitrile, and 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile. Can be mentioned. Of these, 2,2'-azobisisobutyronitrile is preferable. When using a polymerization initiator, the usage-amount of a polymerization initiator has preferable 0.01-5 mass parts with respect to 100 weight part of polymerizable monomers.

  As the surfactant, an anionic surfactant, a cationic surfactant, a nonionic surfactant, an amphoteric surfactant, and a polymer type dispersant can be used. As for the usage-amount of surfactant, 0.01-10 mass parts is preferable with respect to 100 mass parts of polymerizable monomers. Moreover, the following are mentioned as a dispersion stabilizer. Organic fine particles (polystyrene fine particles, polymethyl methacrylate fine particles, polyacrylic acid fine particles and polyepoxide fine particles), silica (colloidal silica), calcium carbonate, calcium phosphate, aluminum hydroxide, barium carbonate, magnesium hydroxide and the like. As for the usage-amount of a dispersion stabilizer, 0.01-20 mass parts is preferable with respect to 100 mass parts of polymerizable monomers.

  The suspension polymerization is preferably carried out in a sealed state using a pressure vessel. Moreover, after suspending a polymerizable monomer with a disperser or the like, the polymerizable monomer may be transferred to a pressure vessel and subjected to suspension polymerization, or may be suspended in a pressure vessel. The polymerization temperature is preferably 50 ° C to 120 ° C. Although the polymerization may be performed under atmospheric pressure, it is preferably performed under pressure (at a pressure obtained by adding 0.1 to 1 MPa to the atmospheric pressure) so that the inclusion substance is not vaporized. After completion of the polymerization, solid-liquid separation and washing may be performed by centrifugation or filtration. Further, after solid-liquid separation and washing, drying and pulverization may be performed at a temperature equal to or lower than the softening temperature of the resin constituting the thermally expanded microcapsule. Drying and pulverization can be performed by a known method, and an air dryer, a normal air dryer, and a Nauta mixer can be used. Further, drying and pulverization can be simultaneously performed by a pulverization dryer. The surfactant and the dispersion stabilizer can be removed by repeating washing and filtration after producing hollow resin particles.

(Method for forming preliminary coating layer)
Then, the formation method of a preliminary coating layer is demonstrated. In the preliminary coating layer, rubber is used as a binder. Therefore, a preliminary coating layer can be formed by extruding the conductive substrate and the unvulcanized rubber composition integrally using an extruder equipped with a crosshead. A crosshead is an extrusion die that is used to form a coating layer of an electric wire or a wire, and is installed at the tip of a cylinder of an extruder. After the preliminary coating layer is formed and dried, cured, or cross-linked, the surface of the preliminary coating layer is polished to remove a part of the shell of the hollow resin particles to obtain a bowl shape. As a polishing method, a cylindrical polishing method or a tape polishing method can be used. Examples of the cylindrical polishing machine include a traverse type NC cylindrical polishing machine and a plunge cut type NC cylindrical polishing machine. Moreover, the method of adhere | attaching or coat | covering the sheet | seat shape or tube-shaped layer which formed and hardened | cured the conductive resin composition into the predetermined film thickness with respect to a conductive base | substrate is mentioned. Furthermore, there is a method in which the conductive resin composition is placed in a mold in which a conductive substrate is disposed and cured to form a preliminary coating layer. A method of forming a layer of a conductive resin composition on a conductive substrate by a coating method such as electrostatic spray coating, dipping coating or roll coating and then curing it by drying, heating, crosslinking or the like is also included.

(Method for forming irregular shape by opening bowl-shaped resin particles)
(A) When the thickness of the preliminary coating layer is 5 times or less of the volume average particle size of the hollow resin particles When the thickness of the preliminary coating layer is 5 times or less of the volume average particle size of the hollow resin particles, In many cases, convex portions derived from hollow resin particles are formed on the surface of the preliminary coating layer. In this case, a part of the convex portions of the hollow resin particles can be removed to form a bowl shape, and an uneven shape can be formed by opening the bowl-shaped resin particles. In this case, it is preferable to use a tape polishing method in which the pressure applied to the preliminary coating layer during polishing is relatively small. As an example, the preferable polishing conditions for the pre-coating layer when using the tape polishing method are shown below.

The abrasive tape is obtained by dispersing abrasive grains in a resin and applying it to a sheet-like substrate. Examples of the abrasive grains include aluminum oxide, chromium oxide, silicon carbide, iron oxide, diamond, cerium oxide, corundum, silicon nitride, silicon carbide, molybdenum carbide, tungsten carbide, titanium carbide and silicon oxide. The average particle size of the abrasive grains is preferably 0.01 μm or more and 50 μm or less, and more preferably 1 μm or more and 30 μm or less. The average particle size of the abrasive grains is the median diameter D50 measured by centrifugal sedimentation. The count of the polishing tape having the above-mentioned preferable range of abrasive grains is preferably 500 or more and 20000 or less, and more preferably 1000 or more and 10,000 or less.
Specific examples of the polishing tape are listed below. MAXIMA LAP, MAXIMA T type (all trade names, manufactured by Leflight), RAPICA (registered trademark, manufactured by KOVAX), microfinishing film, wrapping film (all trade names, manufactured by Sumitomo 3M), mirror film, wrapping film (Brand name, Sankyo Rikagaku Co., Ltd.), Mypox (Brand name, Nihon Micro Coating Co., Ltd.)

  During tape polishing, the polishing tape may be in a stopped state or in a state of being sent. The feed rate when feeding the polishing tape is preferably 2 mm / min or more and 500 mm / min or less, more preferably 10 mm / min or more and 300 mm / min or less. Moreover, 0.01 MPa or more and 0.4 MPa or less are preferable and, as for the pressing pressure to the preliminary coating layer of an abrasive tape, 0.1 MPa or more and 0.3 MPa or less are more preferable. In order to control the pressing pressure, a backup roller may be brought into contact with the preliminary coating layer via a polishing tape. Further, it is preferable to perform oscillation during polishing. Moreover, in order to obtain a desired shape, you may perform a grinding | polishing process over multiple times. Further, the rotation speed of the charging member is preferably set to 10 rpm or more and 6000 rpm or less, and more preferably set to 50 rpm or more and 3000 rpm or less. By setting the number of rotations of the charging member within the above range, it is possible to more easily form an uneven shape due to the opening of the bowl-shaped resin particles on the surface of the preliminary coating layer. In addition, even when the thickness of the preliminary coating layer is not more than 5 times the volume average particle diameter of the hollow resin particles, an uneven shape is formed by opening the bowl-shaped resin particles by the method (b) below. Can do.

(B) When the thickness of the preliminary coating layer exceeds 5 times the volume average particle size of the hollow resin particles When the thickness of the preliminary coating layer exceeds 5 times the volume average particle size of the hollow resin particles, On the surface of the layer, a convex portion derived from hollow resin particles may not be formed. In such a case, the uneven shape by the opening of the bowl-shaped resin particles can be formed by utilizing the difference in polishing properties between the hollow resin particles and the material of the preliminary coating layer. The hollow resin particles have a high resilience because they contain a gas inside. On the other hand, as the binder for the preliminary coating layer, a rubber having a relatively low impact resilience and a small elongation is selected. Thereby, the preliminary coating layer can be easily polished, and the hollow resin particles can be hardly polished. When the pre-coating layer in such a state is polished, the hollow resin particles are not polished in the same state as the pre-coating layer, and the bowl shape in which a part of the shell of the hollow resin particles is removed can do. Thereby, the uneven | corrugated shape by the opening of a bowl-shaped resin particle can be formed in the surface of a preliminary | backup coating layer. This method is a method of forming a concavo-convex shape by utilizing the difference in polishing properties between the hollow resin particles and the material of the preliminary coating layer. Therefore, it is preferable to use acrylonitrile butadiene rubber, styrene butadiene rubber, or butadiene rubber as the material (binder) used for the preliminary coating layer from the viewpoint of low resilience and low elongation.

(Polishing method)
As a polishing method, a cylindrical polishing method or the above-described tape polishing method can be used. However, since it is necessary to remarkably bring out a difference in polishing properties of materials, conditions for polishing faster are preferable. From this viewpoint, it is more preferable to use a cylindrical polishing method. Among the cylindrical polishing methods, it is more preferable to use the plunge cut method from the viewpoint that the longitudinal direction of the preliminary coating layer can be simultaneously polished and the polishing time can be shortened. Moreover, it is preferable to perform the spark-out process (polishing process at the penetration rate of 0 mm / min) conventionally performed from the viewpoint of making the polished surface uniform or not performed in as short a time as possible. As an example, 1000-4000 rpm is preferable and, as for the rotation speed of the plunge cut type cylindrical grinding wheel, 2000-4000 rpm is more preferable. The penetration speed (cutting speed) into the preliminary coating layer is preferably 5 to 30 mm / min, and more preferably 10 to 30 mm / min. At the end of the penetration step, there may be a break-in step on the polished surface, and this step is preferably performed within 2 seconds at a penetration rate of 0.1 to 0.2 mm / min. The spark-out process (polishing process at an intrusion rate of 0 mm / min) is preferably 3 seconds or less. In the spark-out step, the number of rotations is preferably set to 50 rpm or more and 500 rpm or less, and more preferably set to 200 rpm or more. By setting it as the said conditions, the uneven | corrugated formation by opening of a bowl-shaped resin particle can be more easily formed in the surface of a preliminary coating layer. It is also possible to combine tape polishing after cylindrical polishing. In the following description, the polished pre-coating layer is simply referred to as “coating layer”.

(Method of unevenly distributing silicone oil on the surface side of the conductive resin layer)
As described above, the silicone oil to be contained in the conductive resin layer is preferably unevenly distributed on the surface side. Examples of means for unevenly distributing silicone oil on the surface of the conductive resin layer include the following methods.
A method of unevenly distributing silicone oil on the surface of the conductive resin layer of the charging member will be described with reference to FIG. By adding silicone oil 73 to the conductive resin layer 72 and then heating the conductive resin layer, the molecular mobility of the binder of the conductive resin layer is increased as shown in (7a) of FIG. The silicone oil moves to the outermost surface of the conductive resin layer. At this time, when the gas permeability of the bowl-shaped resin particles is low, the silicone oil cannot be transferred to the concave portion of the bowl, but is selectively transferred to the binder part beside the bowl-shaped resin particles. Therefore, as shown in (7b) of FIG. 7, silicone oil can be unevenly distributed in the conductive resin layer constituting a part of the surface of the charging member. Since silicone oil is highly insulating, it is easy to control the volume resistivity of the entire conductive resin layer within the desired range by making it unevenly distributed on the surface, and there should be an amount of silicone oil that can sufficiently exhibit the above effects. Can do.

As for the heat treatment method, known means such as a hot air continuous furnace, an oven, a near infrared heating method, a far infrared heating method can be used, but any method capable of heat treating the surface of the coating layer. For example, it is not limited to these means.
Moreover, in order to make silicone oil exist in the conductive resin layer surface side, it is preferable that a bowl-shaped resin particle is a material with low affinity with respect to silicone oil. Examples of such resin materials include acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin, and acrylic resin. Among these, acrylonitrile resin or vinylidene chloride resin is more preferable.

  FIG. 8 shows a schematic configuration of an example of the process cartridge according to the present invention. This process cartridge is configured such that the electrophotographic photosensitive member 102, the charging roller 101, the developing roller 103, the cleaning member 106, and the like are integrated and detachable from the main body of the electrophotographic image forming apparatus.

<Electrophotographic image forming apparatus>
FIG. 9 shows a schematic configuration of an example of an electrophotographic image forming apparatus according to the present invention. The electrophotographic image forming apparatus includes an electrophotographic photosensitive member, a charging device that charges the electrophotographic photosensitive member, a latent image forming device that performs exposure, a developing device that develops a toner image, a transfer device that transfers to a transfer material, and an electrophotographic photosensitive member. It comprises a cleaning device that collects transfer toner on the body, a fixing device that fixes a toner image, and the like. In addition, the electrophotographic image forming apparatus shown in FIG. 9 is equipped with a process cartridge according to the present invention.
The electrophotographic photosensitive member 102 is a rotary drum type having a photosensitive layer on a conductive substrate. The electrophotographic photosensitive member is driven to rotate at a predetermined peripheral speed (process speed) in the direction of the arrow.
The charging device includes a contact-type charging roller 101 that is placed in contact with the electrophotographic photosensitive member 102 by contacting the electrophotographic photosensitive member 102 with a predetermined pressing force. The charging roller 101 is driven rotation that rotates in accordance with the rotation of the electrophotographic photosensitive member 102, and charges the electrophotographic photosensitive member 102 to a predetermined potential by applying a predetermined DC voltage from the charging power source 109. As a latent image forming apparatus (not shown) that forms an electrostatic latent image on the electrophotographic photosensitive member 102, for example, an exposure apparatus such as a laser beam scanner is used. An electrostatic latent image is formed by irradiating the uniformly charged electrophotographic photosensitive member 102 with exposure light 107 corresponding to image information.
The developing device includes a developing sleeve or a developing roller 103 disposed close to or in contact with the electrophotographic photosensitive member 102. The electrostatic latent image is developed by applying the electrostatically treated toner from the developing roller 103 to the same polarity as the charged polarity of the electrophotographic photosensitive member, and a toner image is formed. In this electrophotographic image forming apparatus, so-called reversal development is performed in which a toner image is formed on an exposed portion.
The transfer device has a contact-type transfer roller 104. The transfer roller 104 transfers the toner image from the electrophotographic photosensitive member 102 to a transfer material such as plain paper. The transfer material is conveyed by a paper feeding system having a conveying member.
The cleaning device includes a blade-type cleaning member 106 and a collection container 108, and mechanically scrapes off and collects the transfer residual toner remaining on the electrophotographic photosensitive member 102 after the transfer. Here, it is possible to omit the cleaning device by adopting a development simultaneous cleaning system in which the transfer device collects the transfer residual toner. The fixing roller 105 is composed of a heated roll, fixes the transferred toner image on the transfer material, and discharges the toner image outside the apparatus.

Hereinafter, the present invention will be described in more detail with reference to specific production examples and examples. However, the present invention is not limited to these. In addition, all the parts and% of the following Examples and Comparative Examples are based on mass unless otherwise specified.
Prior to Examples, Production Examples 1 to 8 relating to charging members (production of resin particles 1 to 8), measurement of volume average particle diameter of resin particles, Production Examples 9 to 14 (production of sheets 1 to 6 for measuring gas permeability) ), Measurement of oxygen gas permeability of resin particles, Production Examples 15 to 39 (Production of conductive rubber compositions 1 to 25) will be described. Subsequently, Production Examples 40 to 42 relating to the photoreceptor (synthesis of polyarylate resin A and polycarbonate resin B) will be described.

<Manufacture of resin particles>
[Production Example 1: Production of resin particles 1]
An aqueous mixed solution composed of 4000 parts by mass of ion-exchanged water, 9.0 parts by mass of colloidal silica as a dispersion stabilizer, and 0.15 parts by mass of polyvinylpyrrolidone was prepared. Next, 50 parts by mass of acrylonitrile, 45 parts by mass of methacrylonitrile and 5 parts by mass of methyl methacrylate as a polymerizable monomer, 12.5 parts by mass of normal hexane as an inclusion substance, and dicumyl peroxide 0 as a polymerization initiator An oily mixed solution consisting of .75 parts by mass was prepared. After this oily mixture was added to the aqueous mixture, a dispersion was prepared by further adding 0.4 parts by mass of sodium hydroxide.
The obtained dispersion was stirred and mixed for 3 minutes using a homogenizer, charged into a nitrogen-substituted polymerization reaction vessel, and reacted at 60 ° C. for 20 hours with stirring at 400 rpm to prepare a reaction product. The obtained reaction product was repeatedly filtered and washed with water, and then dried at 80 ° C. for 5 hours to obtain resin particles. The resin particles were pulverized and classified by a sonic classifier to obtain resin particles 1 having a volume average particle size of 30 μm.

[Production Example 2: Production of resin particles 2]
Resin particles 2 having a volume average particle size of 15 μm were produced in the same manner as in Production Example 1 except that the classification conditions were changed.

[Production Examples 3 to 8: Production of resin particles 3 to 8]
Except for changing the amount of colloidal silica used, the type and amount of the polymerizable monomer, and the number of stirring revolutions during polymerization as shown in Table 1, resin particles 3 to 3 in the same manner as in Production Example 1 were used. 8 was produced.

<Measurement of volume average particle diameter of resin particles>
The volume average particle diameters of the obtained resin particles 1 to 8 were measured using a laser diffraction type particle size distribution meter Coulter LS230 type particle size distribution meter (trade name, manufactured by Coulter Inc.). For the measurement, an aqueous module was used, and pure water was used as a measurement solvent. First, after the inside of the measurement system of the particle size distribution meter was washed with pure water for about 5 minutes, 10 mg to 25 mg of sodium sulfite was added as an antifoaming agent to the measurement system, and a background function was executed. Next, a surfactant (trade name: Contaminone (registered trademark) N (non-ionic surfactant, anionic surfactant, neutral detergent for pH 7 precision measuring instrument cleaning consisting of organic builder) in 50 ml of pure water. 3 to 4 drops of a diluted solution obtained by diluting a 10 mass% aqueous solution) manufactured by Wako Pure Chemical Industries Ltd. with ion-exchanged water about 3 times by mass, and further adding 1 mg to 25 mg of a measurement sample. The aqueous solution in which the sample was suspended was subjected to dispersion treatment for 1 to 3 minutes with an ultrasonic disperser to prepare a test sample solution. Measurement was performed by gradually adding a test sample solution into the measurement system of the measurement apparatus and adjusting the test sample concentration in the measurement system so that the PIDS on the screen of the apparatus was 45% or more and 55% or less. The volume average particle diameter (μm) was calculated from the obtained volume distribution. The results are shown in Table 1.

<Manufacture of gas permeability measurement sheet>
[Production Example 9: Production of gas permeability measurement sheet 1]
The gas permeability measuring sheet is a sheet for measuring the gas permeability of a resin material obtained by removing the inclusion substance from the resin particles. The resin particles 1 were heated and decompressed at 100 ° C. to remove the encapsulated material, whereby a resin composition 1 was obtained. Thereafter, the resin composition 1 is filled in a mold (Φ70 mm, depth 500 μm) heated to 160 ° C., and pressurized at a pressure of 10 MPa, for measuring a circular gas permeability of 70 mm in diameter and 500 μm in thickness. Sheet 1 was obtained.

[Production Examples 10 to 14: Production of gas permeability measurement sheets 2 to 6]
Gas permeability measurement sheets 2 to 6 were obtained in the same manner as in Production Example 9 except that the resin particles 4 to 8 were used instead of the resin particles 1.

<Measurement of oxygen gas permeability of sheet>
Based on the differential pressure method described in JIS K7126, oxygen gas permeability was measured using the gas permeability measurement sheets 1 to 6 under the following conditions.
Measuring instrument: Gas permeability measuring device M-C3 type (trade name, manufactured by Toyo Seiki Seisakusho)
Gas used: Oxygen gas equivalent to JIS K1101 Measurement temperature: 23 ± 0.5 ° C
Test pressure: 760mmHg
Transmission area: 38.46 cm ² (Φ70 mm)
Sample thickness: 500 μm
The specific operation is as follows. First, a gas permeability measurement sheet was mounted on a permeation cell and fixed with a uniform pressure so that no air leakage occurred. After evacuating the low-pressure side and high-pressure side in the measuring apparatus, the low-pressure side was stopped and kept in a vacuum. Thereafter, oxygen gas was introduced into the high pressure side at 1 atm, and the pressure on the high pressure side at that time was Pu. After the pressure on the low-pressure side starts to rise and after confirming the permeation of oxygen gas, draw a permeation curve (horizontal axis: time, vertical axis: pressure), and measure until the straight line where the permeation is steady is confirmed. went. After completion of the measurement, the slope of the permeation curve was d _p / _dt, and the oxygen gas permeability GTR (cm ³ / (m ² · 24 h · atm)) was calculated using the following formula (9). The results are shown in Table 2.

(Vc: low pressure side volume (cm ³ ), T: test temperature (K), Pu: high pressure side pressure (mmHg),
A: Permeation area (m ² ), d _p / d _t : Pressure change on the low pressure side in unit time (h) (mmHg))

<Manufacture of conductive rubber composition>
[Production Example 15: Production of conductive rubber composition 1]
In a closed mixer adjusted to 50 ° C. by adding other materials shown in the column of component (1) in Table 3 to 100 parts by mass of acrylonitrile butadiene rubber (NBR) (trade name: N230SV, manufactured by JSR) Kneaded for 15 minutes. The material shown in the column of the component (2) of Table 3 was added to this. Subsequently, it knead | mixed for 10 minutes with the double roll machine cooled to the temperature of 25 degreeC, and the conductive rubber composition 1 was obtained. The composition of the conductive rubber composition 1 is shown in Table 5. In Table 5, “phr” means parts by mass of each material with respect to 100 parts by mass of resin (rubber).

[Production Examples 16 to 21: Production of conductive rubber compositions 2 to 7]
Conductive rubber compositions 2 to 7 were obtained in the same manner as in Production Example 15 except that the resin particles 1 were changed to resin particles (resin particles 2 to 7) shown in Table 5 in Production Example 15.

[Production Example 22: Production of conductive rubber composition 8]
With respect to 100 parts by mass of styrene butadiene rubber (SBR) (trade name: Toughden (registered trademark) 2003, manufactured by Asahi Kasei Co., Ltd.), other materials shown in the column of component (1) in Table 4 were added and adjusted to 80 ° C. It knead | mixed for 15 minutes with the airtight mixer. To this, the material shown in the column of component (2) in Table 4 was added. Subsequently, it knead | mixed for 10 minutes with the double roll machine cooled to the temperature of 25 degreeC, and the conductive rubber composition 8 was obtained.

[Production Example 23: Production of conductive rubber composition 9]
In Production Example 15, the acrylonitrile butadiene rubber was changed to butadiene rubber (BR) (trade name: JSR BR01, manufactured by JSR), and carbon black was changed to 30 parts by mass. Rubber composition 9 was obtained.

[Production Example 24: Production of conductive rubber composition 10]
A conductive rubber composition 10 was obtained in the same manner as in Production Example 15 except that no silicone oil was added.

[Production Examples 25 to 38: Production of conductive rubber compositions 11 to 24]
Conductive rubber compositions 11 to 24 were obtained in the same manner as in Production Example 15 except that the oil type and the number of parts of the added silicone oil were changed as shown in Table 5. Table 6 shows a list of types of silicone oil used.

[Production Example 39: Production of conductive rubber composition 25]
In Production Example 15, a conductive rubber composition 25 was obtained in the same manner as in Production Example 15 except that the silicone oil was not added and the resin particles 1 were changed to resin particles 8.

<Manufacture of polyarylate resin A>
[Production Example 40: Production of resin A1]
An acid halide solution was prepared by dissolving 3.3 g of isophthalic acid chloride and 3.3 g of terephthalic acid chloride in dichloromethane. In addition to the acid halide solution, 4.2 g of a siloxane derivative represented by the following formula (a-1), 6.8 g of a diol represented by the following formula (a-2), and the following formula (a-3) 3.6 g of the diol was dissolved in a 10% aqueous sodium hydroxide solution. Further, tributylbenzylammonium chloride was added as a polymerization catalyst and stirred to prepare a diol compound solution.

Next, the acid halide solution was added to the diol compound solution with stirring to initiate polymerization. The polymerization reaction was performed for 3 hours with stirring while keeping the reaction temperature at 25 ° C or lower. Thereafter, the polymerization reaction was terminated by adding acetic acid, and washing with water was repeated until the aqueous phase became neutral. Subsequently, this liquid phase was dropped into methanol, and the precipitate was filtered and dried to obtain a white polymer (resin A1).
The resulting resin A1 had a viscosity average molecular weight of 21,000. The viscosity average molecular weight was calculated as follows. 0.5 g of a sample was dissolved in 100 ml of dichloromethane, and the specific viscosity at 25 ° C. was measured using an Ubbelohde viscometer. The intrinsic viscosity is obtained from the obtained specific viscosity, and K (proportional constant part) and a (exponential part; sometimes expressed by α) in the Mark-Houwink viscosity formula are each 1.23. The viscosity average molecular weight was calculated as ^x10-4 and 0.83.
Moreover, when content of the part corresponded to the structure represented by Formula (1) contained in resin A1 by the said method was analyzed, it was 20 mass%.

<Manufacture of polycarbonate resin B>
[Production Example 41: Production of resin B1]
12.0 g of a diol represented by the following formula (b-1) was dissolved in a 10% aqueous sodium hydroxide solution. Dichloromethane was added to this solution and stirred, and 15 g of phosgene was blown in over 1 hour while maintaining the solution temperature at 10 ° C. or higher and 15 ° C. or lower. When about 70% of phosgene was blown in, 4.2 g of the siloxane derivative represented by the formula (a-1) and 4.0 g of the diol represented by the formula (a-3) were added to the solution. After the introduction of phosgene was completed, the reaction solution was emulsified by vigorous stirring, triethylamine was added, and the mixture was stirred for 1 hour. Thereafter, the dichloromethane phase was neutralized with phosphoric acid, and washing with water was repeated until the pH reached about 7. Subsequently, this liquid phase was dropped into isopropanol, and the precipitate was filtered and dried to obtain a white polymer (resin B1).
The obtained resin B1 had a viscosity average molecular weight of 18,000. Moreover, content of the part corresponded to the structure represented by Formula (1) contained in resin B1 was 10 mass%.

[Production Example 42: Production of resin B2]
Resin B2 was synthesized in the same manner as in Production Example 41 except that raw materials corresponding to the structures shown in Table 7 were used. The viscosity average molecular weight of the resin B2 was controlled by adjusting the time from the start of polymerization to the end of polymerization.

  Table 7 shows the configurations of the resin A1, the resins B1 and B2, and the viscosity average molecular weight. In Table 7, “content of formula (1)” means the content (mass%) of the structure represented by formula (1) contained in the resin. “Formula (2), Formula (9), Formula (10), Formula (11), and Formula (12)” are included in the resin, respectively. The structure represented by Formula (11) and Formula (12) is shown. However, when the structural unit represented by Formula (9) or Formula (10) is mixed and used, the type and mixing ratio (mass basis) of each structural unit are shown. In addition, “n” in the formula (10) or the formula (12) means an average value of the number of repetitions n of the structure in parentheses in each formula.

<Production of charging member>
[Production Example T1: Production of Charging Member 1]
(Preparation of conductive substrate)
A thermosetting resin containing 10% by mass of carbon black was applied to a stainless steel substrate having a diameter of 6 mm and a length of 252.5 mm, and the dried one was used as a conductive substrate.

(Formation of conductive resin layer)
Using an extrusion molding apparatus equipped with a cross head, the conductive rubber composition 1 produced in Production Example 15 was coated in a cylindrical shape on the peripheral surface with the conductive substrate as the central axis. The thickness of the coated conductive rubber composition was adjusted to 1.75 mm. The extruded roller was vulcanized at 160 ° C. for 1 hour in a hot air oven, and then the end of the rubber layer was removed to make the length 224.2 mm, and a roller having a preliminary coating layer was produced. The outer peripheral surface of the obtained roller was polished using a plunge cut type cylindrical polishing machine. Pitrified grindstones were used as the abrasive grains, the abrasive grains were green silicon carbide (GC), and the particle size was 100 mesh. The rotational speed of the roller was 350 rpm, and the rotational speed of the grinding wheel was 2050 rpm. Polishing was performed by setting the cutting speed to 20 mm / min, and setting the spark-out time (time at the cutting 0 mm) to 0 seconds, to produce a conductive roller having a conductive resin layer (coating layer). The thickness of the conductive resin layer was adjusted to 1.5 mm. The crown amount of this roller (the average value of the difference between the outer diameter d1 at the center and the outer diameter d2 at positions 90 mm away from the center toward both ends) was 120 μm.
After the polishing, a charging member 1 was obtained by performing a post-heating treatment at 180 ° C. for 60 minutes in an air atmosphere using a hot stove. The charging member 1 had a convex portion derived from the edge of the opening of the bowl-shaped resin particles, a concave portion derived from the opening of the bowl-shaped resin particles, and an exposed portion of the conductive resin layer on the surface thereof. .

[Production Examples T2 to T39: Production of Charging Members 2 to 39]
Charging was performed in the same manner as in the production of the charging member 1 of Production Example T1, except that the type of conductive rubber composition used for the conductive resin layer, the vulcanization temperature, and the heating temperature after polishing were changed as shown in Table 8. Members 2 to 39 were produced.

[Production Example T40: Production of Charging Member 40]
The surface of the charging member produced in the same manner as in Production Example T3 was tape-polished to produce the charging member 40. Tape polishing was performed under the following conditions using a film-type superfinishing apparatus (trade name: Super Finisher SP100, manufactured by Matsuda Seiki Co., Ltd.) as a polishing apparatus. Note that the polishing tape was fed in a stopped state.
Abrasive tape: Wrapping film (manufactured by Sumitomo 3M, abrasive grains: aluminum oxide, average particle size: 9 μm (# 2000))
Roller rotation speed: 1000rpm
Abrasive tape pressing pressure: 0.2 MPa
Rotating direction of polishing tape and roller: opposite direction (counter direction)

[Production Example T41: Production of Charging Member 41]
The surface of the charging member produced in the same manner as in Production Example T13 was tape-polished under the same conditions as in Production Example T40 to produce charging member 41.

[Production Example T42: Production of Charging Member 42]
A charging member 42 was produced in the same manner as in Production Example T3 except that the heating after polishing was not performed in Production Example T3.

[Production Example T43: Production of Charging Member 43]
A charging member 43 was produced in the same manner as in Production Example T13 except that heating after polishing was not performed in Production Example T13.

[Production Example T44: Production of Charging Member 44]
A charging member 44 was produced in the same manner as in Production Example T26 except that the heating after polishing was not performed in Production Example T26.

[Production Example T45: Production of Comparative Charging Member C1]
A comparative charging member C1 was produced in the same manner as in Production Example T1, except that the conductive rubber composition 1 was changed to the conductive rubber composition 10 and heating after polishing was not performed.

[Production Example T46: Production of Comparative Charging Member C2]
A comparative charging member C2 was produced in the same manner as in Production Example T1, except that the conductive rubber composition 1 was changed to the conductive rubber composition 25 and heating after polishing was not performed.

<Measurement of physical properties of charging member>
The following physical property measurements were performed on the obtained charging members 1 to 44 and comparative charging members C1 and C2. The measurement results are shown in Table 8 and Table 9.

[1. Measurement of electrical resistance of charging member]
A load was applied to both ends of the conductive substrate by bearings to bring the charging member into contact with a columnar metal having the same curvature as that of the electrophotographic photosensitive member so as to be parallel. In this state, the cylindrical metal was rotated by a motor, and a DC voltage of −200 V was applied from the stabilized power source while the charging member in contact was driven to rotate. The current flowing at this time was measured with an ammeter, and the electric resistance value (volume resistivity) of the charging member was calculated. Each load was 4.9 N, the diameter of the metal cylinder was 30 mm, and the rotation of the metal cylinder was a peripheral speed of 45 mm / sec. In the measurement, the charging member was left in an environment of a temperature of 23 ° C. and a relative humidity of 50% for 24 hours or more, and the measurement was performed using a measuring apparatus placed in the environment.

[2. Measurement of surface roughness Rzjis and average unevenness Sm of charging member]
The surface roughness Rzjis and the average unevenness distance Sm of the charging member are measured using a surface roughness measuring instrument (trade name: SE-3500, manufactured by Kosaka Laboratory Co., Ltd.) according to the standard of JIS B 0601-1994 surface roughness. It was measured. Rzjis and Sm were measured at six randomly selected charging members, and the average value was calculated. The cut-off value is 0.8 mm and the evaluation length is 8 mm.

[3. Measuring the shape of bowl-shaped resin particles]
The measurement points are charged at each of the five longitudinal locations at the center of the charging member in the longitudinal direction, at positions 45 mm away from the center toward both ends, and at positions 90 mm away from the center toward both ends. A total of 10 locations of 2 locations (phase 0 ° and 180 °) in the circumferential direction of the member were used. At each of these measurement locations, the conductive resin layer was cut out by using a focused ion beam processing observation apparatus (trade name: FB-2000C, manufactured by Hitachi, Ltd.) by 20 nm over 500 μm, and a cross-sectional image thereof was taken. Then, the obtained cross-sectional images were combined to calculate a three-dimensional image of the bowl-shaped resin particles. As shown in FIG. 6, “maximum diameter” 55 and “minimum diameter of opening” 63 were calculated from the stereoscopic image. From the three-dimensional image, the “difference between the outer diameter and the inner diameter” of the bowl-shaped resin particles, that is, the “shell thickness” was calculated at any five points of the bowl-shaped resin particles. Such measurement is performed on 10 resin particles in the field of view, and the average value of the 100 measured values obtained is calculated, and “maximum diameter”, “minimum diameter of the opening”, and “shell "Thickness". When measuring the thickness of the shell, for each bowl-shaped resin particle, the thickness of the thickest part of the shell is not more than twice the thickness of the thinnest part, that is, the thickness of the shell is substantially uniform. It was confirmed that.

[4. Measurement of the height difference between the top of the protrusion on the surface of the charging member and the bottom of the recess]
The surface of the charging member was observed with a laser microscope (trade name: LXM5 PASCAL, manufactured by Carl Zeiss) in a visual field of 0.5 mm in length and 0.5 mm in width. Two-dimensional image data was obtained by scanning the laser in the XY plane within the field of view, and further, the focal point was moved in the Z direction, and the above scanning was repeated to obtain three-dimensional image data. As a result, first, it was confirmed that there were a concave portion derived from the opening of the bowl-shaped resin particles and a convex portion derived from the edge of the opening of the bowl-shaped resin particles. Further, the height difference 54 between the apex of the convex portion and the bottom portion of the concave portion was calculated. Such an operation was performed on two bowl-shaped resin particles in the field of view. And the same measurement was performed about the longitudinal direction 50 places of the charging member, the average value of the obtained 100 resin particles was calculated, and this value was made into the "height difference".

[5. Measurement of the proportion of silicon element present on the surface of the conductive resin layer of the charging member]
Using X-ray photoelectron spectroscopy (ESCA), the abundance ratio (atomic%) of silicon element to the constituent elements on the surface of the conductive resin layer was calculated using the method described above. The measurement was performed on the outermost surface of the conductive resin layer and the abundance ratio of silicon element to the constituent elements in the conductive resin layer at positions of 0 nm (outermost surface), 50 nm, and 100 nm from the outermost surface by sputtering.

<Production of photoconductor>
[Production Example P1: Production of Photoreceptor 1]
(Preparation of support)
An aluminum cylinder having the same shape as the photosensitive drum for a monochrome laser printer (trade name: LBP6700) manufactured by Canon Inc. was used as a support (conductive support).

(Formation of conductive layer)
214 parts of titanium oxide (TiO ₂ ) particles coated with oxygen-deficient tin oxide (SnO ₂ ) as metal oxide particles, phenol resin (monomer / oligomer of phenol resin, trade name: Pryofen J-) as binder 325, 132 parts manufactured by DIC (formerly Dainippon Ink and Chemicals, Inc., resin solid content: 60% by mass), and 98 parts of 1-methoxy-2-propanol as a solvent, 450 parts of glass beads having a diameter of 0.8 mm Was put into a sand mill using a dispersion, and a dispersion treatment was performed under the conditions of a rotational speed of 2000 rpm, a dispersion treatment time of 4.5 hours, and a cooling water set temperature of 18 ° C. to obtain a dispersion. Glass beads were removed from this dispersion with a mesh (aperture: 150 μm).
Silicone resin particles (trade name: Tospearl 120, as a surface roughening agent) so as to be 10% by mass with respect to the total mass of the metal oxide particles and the binder material in the dispersion after removing the glass beads. Momentive Performance Materials, Inc., average particle size 2 μm) was added to the dispersion. In addition, silicone oil as a leveling agent (trade name: SH28PA, manufactured by Toray Dow Corning Co., Ltd.) is used so that the total mass of the metal oxide particles and the binder material in the dispersion is 0.01% by mass. A conductive layer coating solution was prepared by adding to the dispersion and stirring. The conductive layer coating solution was dip-coated on a support, and the resulting coating film was dried and thermally cured at 150 ° C. for 30 minutes to form a conductive layer having a thickness of 30 μm.

(Formation of undercoat layer)
Next, 10 parts by mass of copolymerized nylon resin (trade name: Amilan (registered trademark) CM8000, manufactured by Toray Industries, Inc.) and 30 parts by mass of methoxymethylated nylon resin are dissolved in a mixed solution of 500 parts by mass of methanol and 250 parts by mass of butanol. The resulting solution was dip-coated on the conductive layer, placed in a hot air drier adjusted to a temperature of 100 ° C. for 10 minutes, and dried by heating to form an undercoat layer having a thickness of 0.6 μm.

(Formation of charge generation layer)
Crystals having strong peaks at 7.5 °, 9.9 °, 16.3 °, 18.6 °, 25.1 ° and 28.3 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction 10 parts of a hydroxygallium phthalocyanine (charge generating substance) in the form was prepared. It was mixed with 250 parts of cyclohexanone and 5 parts of polyvinyl butyral resin (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.), and 1 in a 23 ± 3 ° C. atmosphere in a sand mill apparatus using glass beads having a diameter of 1 mm. Time dispersed. After dispersion, a coating solution for charge generation layer was prepared by adding 250 parts of ethyl acetate. The charge generation layer coating solution was dip-coated on the undercoat layer, and the resulting coating film was dried at 100 ° C. for 10 minutes to form a charge generation layer having a thickness of 0.26 μm.

(Formation of charge transport layer)
As a charge transport material, 8 parts of the compound represented by the formula (13-1) and 2 parts of the compound represented by the formula (13-8), and 0.4 parts of the resin A1 synthesized in Production Example 40 as a resin. A structural unit represented by the formula (9-1), a structural unit represented by the formula (9-2), a structural unit represented by the formula (9-13), and the formula (9- 14) 9.6 parts of a polyarylate resin (viscosity average molecular weight: 40,000) containing the structural unit represented by 14) at a mass ratio of 3.5: 3.5: 1.5: 1.5, and dimethoxy A coating solution for a charge transport layer was prepared by dissolving in a mixed solvent consisting of 40 parts of methane, 60 parts of o-xylene and 5 parts of methyl benzoate. The charge transport layer coating solution was dip-coated on the charge generation layer, and the resulting coating film was dried at 120 ° C. for 1 hour to form a charge transport layer having a thickness of 16 μm. Thus, a photoreceptor 1 having a charge transport layer as a surface layer was produced. Table 10 shows the structure of the charge transport material and the resin contained in the charge transport layer of the photoreceptor 1.

[Production Examples P2 to P7: Production of photoconductors 2 to 7]
Photoconductors 2 to 7 were produced in the same manner as in Production Example P1, except that the charge transport material and the resin in the charge transport layer were changed as shown in Table 10.

[Production Example P8: Production of Comparative Photosensitive Member D1]
A comparative photoreceptor D1 was produced in the same manner as in Production Example P1, except that the charge transport material and the resin in the charge transport layer were changed as shown in Table 10.

<Measurement of physical properties of photoconductor>
With respect to the obtained photoreceptors 1 to 7 and comparative photoreceptor D1, the abundance ratio (atomic%) of silicon element with respect to the constituent elements on the outermost surface of the charge transport layer was measured by the method described above. The results are shown in Table 10.
In Table 10, “Charge transport material” indicates the type and number of parts of the charge transport material. “Resin A, resin B” indicates the type of “polyarylate resin A, polycarbonate resin B”. “Other resin” refers to a structural unit of a resin other than the resin A or the resin B contained in the charge transport layer. When two or more kinds of structural units are mixed and used, the type and mixing ratio (mass basis) of each structural unit are shown. “Ratio of resin A and resin B” means the content (% by mass) of resin A or resin B with respect to the total solid content in the charge transport layer.

<Image evaluation>
[Example 1]
[1. Image evaluation after vibration test and drop test]
In order to confirm the influence of rubbing between the charging member 1 and the photosensitive member 1 due to vibration or impact in physical distribution or the like, image evaluation after a vibration test and a drop test was performed.
First, the process cartridge was removed from the packaging box. The attached charging member was removed from the process cartridge, and the charging member 1 was set instead. The charging member 1 was brought into contact with the photosensitive member with a pressing force of a spring of 4.9 N at one end and a total of 9.8 N at both ends. In addition, the attached photosensitive member was removed from the process cartridge, and the photosensitive member 1 was set instead, and the process cartridge according to Example 1 was configured. As a process cartridge, a toner cartridge 524II (trade name, manufactured by Canon Inc.) for printers for performing the following image evaluation was used.
In the vibration test, in accordance with the logistics test standard (JIS Z 0232), the process cartridge after the initial evaluation is returned to the packaging box from which the process cartridge was taken out, and installed in a vibration test apparatus (EMIC CORP. Model 905-FN). In each of the x-, y-, and z-axis directions, a frequency of 10 Hz to 100 Hz, an acceleration of 9.8 m / S ² , a LIN SWEEP sweep direction, and a reciprocating sweep time were performed for 5 minutes and a test time of 1 hour. Subsequently, a drop test was performed. In the drop test, the packaging box containing the process cartridge according to Example 1 provided with the charging member 1 and the photosensitive member 1 was dropped from a position having a height of 1 m at six sides and four corners (bottom corners).

  Image evaluation was performed after the above vibration test and drop test. For image evaluation, a monochrome laser printer (trade name: LBP6700) manufactured by Canon Inc., which is an electrophotographic image forming apparatus having the configuration shown in FIG. 10, was modified to a process speed of 330 mm / sec. Further, a voltage was applied to the charging member 1 from the outside. The applied voltage was −1100 V as a DC voltage. The image resolution was output at 600 dpi. The output of the image is a halftone image (an image that draws a horizontal line with a width of 1 dot and an interval of 2 dots in the direction perpendicular to the rotation direction of the electrophotographic photosensitive member). The presence or absence of image defects was determined according to the following criteria.

(Evaluation of streaky images)
Rank 1: No streak-like image defect is observed.
Rank 2: Only a few streak-like image defects are observed.
Rank 3: It is recognized that streak-like image defects occur in some areas corresponding to the rotation pitch of the charging roller.
Rank 4: A streak-like image defect is recognized in a wide range and is conspicuous.

[2. Image evaluation of banding image caused by slip]
In order to confirm the suppression of the banding image caused by the slip, the image evaluation of the banding image was performed. In the same manner as in the vibration test, a process cartridge according to Example 1 in which the charging member 1 and the photoreceptor 1 were set was prepared. In the same manner as the image evaluation after the vibration test, banding images were evaluated under the same conditions using the process cartridge and the electrophotographic image forming apparatus. At this time, the process cartridge was conditioned for 24 hours in a low-temperature and low-humidity environment having a temperature of 15 ° C. and a relative humidity of 10%, and then image evaluation was performed. Specifically, a halftone image was output, the obtained image was visually observed, and the presence or absence of a horizontal streak-like image defect was determined according to the following criteria.

(Evaluation of horizontal stripe image)
Rank 1: No horizontal streak-like image defect is observed.
Rank 2: Only a few horizontal streak-like image defects are observed.
Rank 3: It is recognized that a horizontal streak-like image defect occurs in a part of the area corresponding to the rotation pitch of the charging roller.
Rank 4: Horizontal streak-like image defects are recognized over a wide area and are conspicuous.

[Examples 2 to 50]
A process cartridge according to Examples 2 to 50 was configured and image evaluation was performed in the same manner as Example 1 except that the charging member and the photoreceptor shown in Table 11 were used. The results are shown in Table 11.

[Comparative Examples 1-3]
A process cartridge according to Comparative Examples 1 to 3 was configured and image evaluation was performed in the same manner as in Example 1 except that the charging member and the photoreceptor shown in Table 11 were used. The results are shown in Table 11.

  Regarding the streak image in the image evaluation after the vibration test, in the process cartridge according to Examples 1 to 50, the silicone oil is present on the surface of the charging member, and due to the rubbing between the charging member and the photoconductor during the vibration test. Charge transfer was suppressed and good evaluation results were obtained. On the other hand, in the process cartridges according to Comparative Examples 1 and 2, silicone oil does not exist on the surface of the charging member, and in Comparative Example 3, silicon element does not exist on the surface of the photoreceptor. As a result, charge was transferred between the charging member and the photosensitive member during the vibration test, and a streak-like image was observed. For the horizontal streak image, in the process cartridges according to Examples 1 to 50 and Comparative Examples 1 to 3, the electric attractive force sufficiently works between the edge portion derived from the bowl-shaped resin particles and the photoconductor, Good evaluation results were obtained.

DESCRIPTION OF SYMBOLS 1 Conductive base | substrate 2 Conductive resin layer 11, 41 Bowl-shaped resin particle 12, 42 Conductive resin layer (binder)
15 Electrophotographic Photoreceptor 51 Bowl-Shaped Resin Particle Opening 52 Concave Derived from Bowl-Shaped Resin Particle Opening 53 Edge of Bowl-Shaped Resin Particle Opening

Claims (9)

A process cartridge that is detachable from the main body of the electrophotographic image forming apparatus,
An electrophotographic photoreceptor, and a charging member for charging the electrophotographic photoreceptor,
The electrophotographic photoreceptor is
A support, a charge generation layer, and a charge transport layer as a surface layer in this order,
The charge transport layer comprises
Including one or both of a polyarylate resin having a structure represented by the following formula (1) and a polycarbonate resin having a structure represented by the following formula (1),
The charging member is
It has a conductive substrate and a conductive resin layer as a surface layer in this order,
The conductive resin layer contains a binder and holds bowl-shaped resin particles having an opening in a state where the opening is exposed on the surface of the charging member,
The surface of the charging member is
A recess derived from the opening of the bowl-shaped resin particles exposed on the surface;
A convex portion derived from the edge of the opening of the bowl-shaped resin particles exposed on the surface;
An exposed portion of the conductive resin layer,
The bowl-shaped resin particles are:
Including at least one resin selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin and acrylic resin,
In the exposed portion of the conductive resin layer, a process cartridge comprising silicone oil in a region from the surface to a depth of 50 nm:
(In Formula (1), R ¹¹ and R ¹² each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. N represents the number of repetitions of the structure in parentheses. The average value of n is 10) It is 200 or less.) The process cartridge according to claim 1, comprising a structure represented by the following formula (15) as a structure represented by the formula (1):
(In formula (15), R ^{151 to} R ¹⁵⁴ each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. Z represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, or A substituted or unsubstituted aryl group, n represents the number of repetitions of the structure in parentheses, and the average value of n is 10 or more and 200 or less. The process cartridge according to claim 1 or 2, wherein the polyarylate resin and the polycarbonate resin have a structure represented by the following formula (2) at least at a part of a terminal.
(In the formula ^{(2), R} 21 ~R ²⁴ are each independently, .Z represents an alkyl group, fluoroalkyl group or a phenyl group, an alkyl group having 1 to 4 carbon atoms, or a phenyl group. m represents the number of repetitions of the structure in parentheses, the average value of m is 1 or more and 3 or less, n represents the number of repetitions of the structure in parentheses, and the average value of n is 10 or more and 200 or less. ). The polyarylate resin has at least one of structural units represented by the following formulas (9) and (10) on the main chain skeleton, and the polycarbonate resin has the following formula (11) on the main chain skeleton. The process cartridge according to any one of claims 1 to 3, comprising at least one of the structural units represented by (12) and (12):
(In Formula (9), R ^{91 to} R ⁹⁸ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. X ⁹ represents an m-phenylene group, p -A phenylene group or a divalent group in which two p-phenylene groups are bonded via an oxygen atom, Y ⁹ represents a single bond, an oxygen atom, a sulfur atom, or a divalent organic group.
(In formula (10), R ^{101 to} R ¹⁰⁴ each independently represents a methyl group, an ethyl group, or a phenyl group. X ¹⁰ represents an m-phenylene group, a p-phenylene group, or two p-phenylene groups. A divalent group in which the group is bonded via an oxygen atom, n represents the number of repetitions of the structure in parentheses, and the average value of n is 10 or more and 150 or less.
(In formula (11), R ^{111 to} R ¹¹⁸ each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Y ¹¹ represents a single bond, an oxygen atom, A sulfur atom or a divalent organic group is indicated.)
(In formula (12), R ^{121 to} R ¹²⁴ each independently represents a methyl group, an ethyl group, or a phenyl group. N represents the number of repetitions of the structure in parentheses. The average value of n is 10 It is 150 or less.)   The abundance ratio of silicon element to constituent elements on the outermost surface of the conductive resin layer of the charging member, measured by using X-ray photoelectron spectroscopy (ESCA), is 0.65 atomic% or more. 5. The process cartridge according to any one of 4 above.   2. The ratio of silicon elements to constituent elements on the outermost surface of the charge transport layer of the electrophotographic photosensitive member, measured using X-ray photoelectron spectroscopy (ESCA), is 3.0 atomic% or more. The process cartridge as described in any one of -5.   The process cartridge according to any one of claims 1 to 6, wherein the binder contains at least one rubber selected from the group consisting of styrene butadiene rubber, butyl rubber, acrylonitrile butadiene rubber, chloroprene rubber, and butadiene rubber. An electrophotographic photoreceptor;
An electrophotographic image forming apparatus comprising a charging member for charging the electrophotographic photosensitive member,
The electrophotographic photoreceptor is
A support, a charge generation layer, and a charge transport layer as a surface layer in this order,
The charge transport layer comprises
Including one or both of a polyarylate resin having a structure represented by the following formula (1) and a polycarbonate resin having a structure represented by the following formula (1),
The charging member is
It has a conductive substrate and a conductive resin layer as a surface layer in this order,
The conductive resin layer contains a binder and holds bowl-shaped resin particles having an opening in a state where the opening is exposed on the surface of the charging member,
The surface of the charging member is
A recess derived from the opening of the bowl-shaped resin particles exposed on the surface;
A convex portion derived from the edge of the opening of the bowl-shaped resin particles exposed on the surface;
An exposed portion of the conductive resin layer,
The bowl-shaped resin particles are:
Including at least one resin selected from the group consisting of acrylonitrile resin, vinylidene chloride resin, methacrylonitrile resin and acrylic resin,
In the exposed portion of the conductive resin layer, an silicone resin is contained in a region from the surface to a depth of 50 nm:
(In Formula (1), R ¹¹ and R ¹² each independently represents an alkyl group, a fluoroalkyl group, or a phenyl group. N represents the number of repetitions of the structure in parentheses. The average value of n is 10) It is 200 or less.) 9. The electrophotographic image forming apparatus according to claim 8, wherein the binder includes at least one rubber selected from the group consisting of styrene butadiene rubber, butyl rubber, acrylonitrile butadiene rubber, chloroprene rubber, and butadiene rubber.