JP4684621B2 - Process cartridge and electrophotographic apparatus - Google Patents

Description

  The present invention provides a process cartridge that integrally supports an electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and is detachable from an electrophotographic apparatus main body. And an electrophotographic apparatus including the process cartridge.

  In an electrophotographic image forming apparatus, that is, an electrophotographic apparatus, an electrophotographic photosensitive member and process means (charging means, developing means, transfer means, cleaning means, etc.) acting on the electrophotographic photosensitive member are integrated. A system is widely adopted in which the cartridge (process cartridge) is detachable from the main body of the electrophotographic apparatus by making it into a cartridge.

  According to this method, the maintenance of the electrophotographic apparatus can be performed by the user himself / herself without depending on the service person, so that the maintainability can be remarkably improved.

  Before the process cartridge is mounted on the main body of the electrophotographic apparatus or when the process cartridge is taken out of the main body of the electrophotographic apparatus for maintenance of the electrophotographic apparatus, the electrophotographic photosensitive member in the process cartridge is subjected to an external impact. It may cause image defects by being damaged or exposed to external light.

  Therefore, the process cartridge preferably has a protective member for protecting the electrophotographic photosensitive member from external impact and external light.

  Examples of such a protective member include a fixed shape part made of plastic or a film sheet to be attached to an electrophotographic photosensitive member. These are removed (removed) when the process cartridge is first attached to the main body of the electrophotographic apparatus.

  However, if the protective member is removed when the process cartridge is first mounted, there is no protective member when the process cartridge is removed from the main body of the electrophotographic apparatus in order to perform maintenance of the electrophotographic apparatus during use. The photoconductor cannot be protected from external impact or external light.

As a technique for solving this problem, for example, in Japanese Patent Laid-Open No. 2001-228780 (Patent Document 1), when the process cartridge is attached to the main body of the electrophotographic apparatus, the electrophotographic photosensitive member is opened to be opened. A process cartridge is disclosed that has a protective member (shutter) that moves and moves to a position that protects the electrophotographic photosensitive member when the process cartridge is not attached to the main body of the electrophotographic apparatus.
JP 2001-228780 A

  A process cartridge having such a shutter is generally configured such that the shutter and the electrophotographic photosensitive member are not in contact with each other. When the shutter and the electrophotographic photosensitive member are in contact, particularly when the shutter and the electrophotographic photosensitive member are in contact with each other in the image forming area of the electrophotographic photosensitive member, the shutter and the electrophotographic photosensitive member are vibrated and the shutter is opened and closed. This is because problems such as scratches due to collisions and rubbing memory may occur. When a problem such as scratches or rubbing memory occurs, a defect occurs in the output image. For example, when a rubbing memory occurs, a density difference occurs in the output image, and when a scratch occurs, the scratch appears in the output image.

  In order to prevent the shutter and the electrophotographic photosensitive member from coming into contact with each other, it is necessary to provide a gap between the shutter and the electrophotographic photosensitive member. The gap is generally 1 mm or more (preferably 2 to 3 mm) in consideration of shutter deflection, bending and shutter installation accuracy.

  That is, in a process cartridge having a shutter, a space that combines the thickness of the shutter and the size of the gap is required as a space for protecting the electrophotographic photosensitive member.

  However, in recent years, there is a high demand for further miniaturization of the electrophotographic apparatus. Along with this, miniaturization of the process cartridge is also desired.

  In order to reduce the size of the process cartridge, it is preferable to reduce a space obtained by combining the thickness of the shutter and the size of the gap.

  Here, when the above-described gap is secured, that is, on the premise that the shutter and the electrophotographic photosensitive member are not in contact with each other, if only the thickness of the shutter is reduced (thin), the thin shutter is easy to bend. In order to prevent contact with the electrophotographic photosensitive member, it is necessary to secure a larger gap. That is, even if only the thickness of the shutter is reduced (thinned), the effect of downsizing the process cartridge is small, or rather the process cartridge may be enlarged.

  Accordingly, in order to reduce the size of the process cartridge, it is preferable to reduce the size of the gap, and finally, to have a configuration in which the shutter and the electrophotographic photosensitive member are in contact with each other.

  In addition, from the viewpoint of preventing exposure of the electrophotographic photosensitive member to external light, a configuration without the above-described gaps into which external light may be inserted, that is, a configuration in which the shutter and the electrophotographic photosensitive member are in contact, particularly It is preferable that the shutter and the electrophotographic photosensitive member be in contact with each other in the image forming area of the electrophotographic photosensitive member.

  An object of the present invention is to reduce the size of a process cartridge having a shutter and an electrophotographic apparatus to which the process cartridge is mounted, and when the process cartridge is not attached to the main body of the electrophotographic apparatus, In order to prevent exposure to external light, even if the gap is eliminated from the process cartridge, that is, the shutter and the electrophotographic photosensitive member are in contact with each other, the shutter and It is an object of the present invention to provide a process cartridge that does not cause problems such as scratches and rubbing memory even when in contact with an electrophotographic photosensitive member, and to provide an electrophotographic apparatus on which the process cartridge is mounted.

The present invention provides a process cartridge that integrally supports an electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and is detachable from an electrophotographic apparatus main body. Because
A shutter for protecting the electrophotographic photosensitive member;
The shutter moves to a position in contact with the electrophotographic photosensitive member in the image forming area of the electrophotographic photosensitive member when the process cartridge is not attached to the main body of the electrophotographic photosensitive member. A shutter that moves to an open position to open the electrophotographic photoreceptor when mounted;
The elastic deformation rate of the shutter is 48% or more and 53% or less,
F _(S) is the maximum coefficient of static friction of the shutter when measured with a urethane rubber blade having a Wallace hardness of 73 ° and a dimension of 5 mm wide × 10 mm long × 2 mm thick in contact with the shutter. The maximum surface of the electrophotographic photosensitive member when measured by bringing a urethane rubber blade having a Wallace hardness of 73 ° and dimensions of 5 mm in width × 10 mm in length × 2 mm in thickness into contact with the electrophotographic photosensitive member. When the coefficient of static friction is F _(D) , the process cartridge is characterized by satisfying a condition represented by the following formula (1) or a condition represented by the following formula (2).
F _(S) × F _(D) ≦ 0.85 (1)
F _(S) × F _(D) ≧ 1.25 (2)
The present invention is also an electrophotographic apparatus provided with the above process cartridge.

  According to the present invention, in order to reduce the size of a process cartridge having a shutter and an electrophotographic apparatus to which the process cartridge is attached, and when the process cartridge is not attached to the main body of the electrophotographic apparatus, In order to prevent exposure to external light, even if the gap is eliminated from the process cartridge, that is, the shutter and the electrophotographic photosensitive member are in contact with each other, the shutter and A process cartridge that does not cause problems such as scratches and rubbing memory even when it is in contact with the electrophotographic photosensitive member can be provided, and an electrophotographic apparatus equipped with the process cartridge can be provided.

  Hereinafter, the present invention will be described in detail.

  The electrophotographic photosensitive member and the shutter protecting it vibrate when the shutter is closed and in contact with the electrophotographic photosensitive member, and the process cartridge vibrates, and the outside of the shutter (the electrophotographic photosensitive member and the shutter are in contact with each other). When an external force is applied from the opposite side of the surface, the force causing the shutter and the electrophotographic photosensitive member to shift and the force to rub against each other works. As a result, scratches and rubbing memory are generated on the electrophotographic photosensitive member. appear.

As a result of the study by the present inventors, the maximum static friction coefficient F _{(S) of} the shutter and the maximum static friction coefficient F _(D) of the surface of the electrophotographic photosensitive member are the conditions represented by the following formula (1) or It was found that the above-mentioned problems such as scratches and rubbing memory do not occur by satisfying the condition represented by the following formula (2).
F _(S) × F _(D) ≦ 0.85 (1)
F _(S) × F _(D) ≧ 1.25 (2)

  The above problems such as scratches and rubbing memory may cause the process cartridge to be electrophotographic before the process cartridge is attached to the electrophotographic apparatus main body or during maintenance of the electrophotographic apparatus rather than when the process cartridge is attached to or detached from the electrophotographic apparatus main body. This occurs more prominently when out of the main body. This is because the electrophotographic apparatus is often provided with guide means (guides and rails) for mounting the process cartridge in the correct position, and the shutter is opened and closed only once for each attachment / detachment. When the cartridge is attached or detached, the shutter and the electrophotographic photosensitive member rub against each other only once, whereas the process cartridge is electrophotographic before the process cartridge is attached to the main body of the electrophotographic apparatus or maintenance of the electrophotographic apparatus. This is because when the toner is taken out of the apparatus main body, friction between the shutter and the electrophotographic photosensitive member due to vibration is likely to occur.

When the maximum static friction coefficient F _{(S) of the} shutter and the maximum static friction coefficient F _{( D)} of the surface of the electrophotographic photosensitive member satisfy the condition expressed by the following formula (1), the shutter and the electrophotographic photosensitive member Although they slide with each other and friction occurs to some extent, the electrophotographic photosensitive member is not damaged because the torque load due to friction is small. In addition, when a large amount of heat is generated due to friction, electrons are generated by thermal excitation, which causes a sliding memory on the electrophotographic photosensitive member, but the shutter and the electrophotographic photosensitive member slide well with each other, Since the amount of heat generated by friction is small, no rubbing memory is generated on the electrophotographic photosensitive member.

On the other hand, if the maximum static friction coefficient F _{(S) of} the shutter and the maximum static friction coefficient F _{( D)} of the surface of the electrophotographic photosensitive member satisfy the condition expressed by the following formula (2), the shutter and the electrophotographic Since the photosensitive members do not slide with each other and no friction occurs between the shutter and the electrophotographic photosensitive member, no scratches or rubbing memory occurs on the electrophotographic photosensitive member.

Note that the maximum static friction coefficient F _{(S) of} the shutter and the maximum static friction coefficient F _{( D)} of the surface of the electrophotographic photosensitive member are represented by the conditions shown by the following formula (3) or the following formula (4). It is more preferable to satisfy the conditions.
F _(S) × F _(D) ≦ 0.65 (3)
F _(S) × F _(D) ≧ 1.50 (4)

The universal hardness of the shutter is HU _(S) [N / mm ² ], the universal hardness of the surface of the electrophotographic photosensitive member is HU _(D) [N / mm ² ], and the elastic deformation rate of the shutter is We% _{( S)} [%], where the elastic deformation rate of the surface of the electrophotographic photosensitive member is We% _(D) [%], the condition shown by the following formula (5), the condition shown by the following formula (6), It is more preferable that the condition shown by the following formula (7) and the condition shown by the following formula (8) are satisfied from the viewpoint of suppressing the generation of the scratches and the rubbing memory.
HU _(D) −HU _(S) ≧ 80 (5)
30 ≦ HU _(S) ≦ 120 (6)
We% _(S) ≥ We% _(D) (7)
45 ≦ We% _(S) ≦ 60 (8)

As shown in the above formula (5), the generation of scratches on the electrophotographic photosensitive member can be further suppressed when the universal hardness of the surface of the electrophotographic photosensitive member is larger than the universal hardness of the shutter. It is preferable that it is [N / mm ² ] or more. In particular, the difference is more preferably 100 [N / mm ² ] or more.

As indicated by the above formula (6), the universal hardness of the shutter is preferably 30 [N / mm ² ] or more and 120 [N / mm ² ] or less. If the universal hardness of the shutter is too small, the strength of the shutter becomes weak, and scratches and rubbing memory may occur due to deformation of the shutter due to external impact. On the other hand, if the universal hardness of the shutter is too large, the surface of the electrophotographic photosensitive member may be damaged by the too hard shutter.

  Further, as shown by the above formula (7), the generation of scratches on the electrophotographic photosensitive member can be further suppressed when the elastic deformation rate of the shutter is larger than the elastic deformation rate of the surface of the electrophotographic photosensitive member. This is presumably because the shutter absorbs the external shock by deformation before the electrophotographic photosensitive member against the external shock.

  As indicated by the above formula (8), the elastic deformation rate of the shutter is preferably 45% or more and 60% or less. If the elastic deformation rate of the shutter is too small, the shutter is difficult to deform, and the external shock absorbing effect of the shutter may be difficult to obtain. On the other hand, if the elastic deformation rate of the shutter is too large, a minute rubbing between the electrophotographic photosensitive member and the shutter occurs, and scratches or rubbing memory may occur on the electrophotographic photosensitive member.

  FIG. 1 shows an example of a schematic configuration of a process cartridge according to the present invention.

  The process cartridge having the configuration shown in FIG. 1 includes an electrophotographic photosensitive member 1, a charging unit (charging roller) 3, a developing unit having a toner carrier 5s and a toner 5t, and a cleaning unit (cleaning blade) 7. In particular, it is configured to be attached to the frame body 9 to form a cartridge and to be detachable from the main body of the electrophotographic apparatus.

  A shutter 20 protects the surface of the electrophotographic photosensitive member 1 when the process cartridge is taken out from the main body of the electrophotographic apparatus. In FIG. 1, the shutter 20 is in contact with the surface of the electrophotographic photosensitive member 1 in the image forming area of the electrophotographic photosensitive member 1. When the process cartridge is mounted on the electrophotographic apparatus main body, the shutter 20 is opened (moved to a position indicated by 20 'in FIG. 1) to transfer the toner image onto a transfer material (paper or the like). Not disturb.

  The shape of the shutter may be any shape that contacts the electrophotographic photosensitive member in the image forming area of the electrophotographic photosensitive member when the process cartridge is not mounted on the main body of the electrophotographic apparatus. The thickness of the portion of the shutter in contact with the electrophotographic photosensitive member, that is, the distance between the surface in contact with the electrophotographic photosensitive member and the surface opposite to the surface (also simply referred to as the thickness of the shutter) is 1 mm or more. It is preferable that When the thickness of the shutter is 1 mm or more, the degree of deformation due to an external impact of the shutter itself is reduced, and thus the effect of the present invention can be obtained more remarkably.

  FIG. 2 shows an example of a schematic configuration of an electrophotographic apparatus equipped with the process cartridge having the configuration shown in FIG.

  The electrophotographic photoreceptor 1 is driven to rotate at a predetermined peripheral speed in the direction of the arrow about the shaft 2.

  The surface of the rotationally driven electrophotographic photosensitive member 1 is uniformly charged to a predetermined positive or negative potential by a charging means (charging roller) 3 and then exposed to exposure means (not shown) such as slit exposure or laser beam scanning exposure. ) From the exposure light (image exposure light) 4 output. In this way, electrostatic latent images corresponding to the target image are sequentially formed on the surface of the electrophotographic photosensitive member 1.

  The electrostatic latent image formed on the surface of the electrophotographic photosensitive member 1 is developed with the toner 5t carried on the toner carrying member 5s of the developing means to become a toner image. Next, the toner image formed and supported on the surface of the electrophotographic photosensitive member 1 is transferred from the transfer material supply unit (not shown) by the transfer bias from the transfer unit (transfer roller) 6 to the electrophotographic photosensitive member 1 and the transfer unit 6. Are sequentially transferred to a transfer material (paper or the like) P that is taken out and fed in synchronization with the rotation of the electrophotographic photosensitive member 1.

  The transfer material P that has received the transfer of the toner image is separated from the surface of the electrophotographic photosensitive member 1 and introduced into the fixing means 8 to receive the image fixing, and is printed out as an image formed product (print, copy). Is done.

  The surface of the electrophotographic photosensitive member 1 after the transfer of the toner image is cleaned by a cleaning means (cleaning blade) 7 after removal of the transfer residual toner, and is further subjected to pre-exposure light (not shown) from pre-exposure means (not shown). After being subjected to static elimination processing (not shown), it is repeatedly used for image formation. As shown in FIG. 2, when the charging unit 3 is a contact charging unit using a charging roller or the like, pre-exposure is not necessarily required.

  In FIG. 2, a process cartridge in which an electrophotographic photosensitive member 1, a charging unit (charging roller) 3, a developing unit having a toner carrier 5s and a toner 5t, and a cleaning unit (cleaning blade) 7 are integrally formed into a cartridge. Is configured to be detachable from the main body of the electrophotographic apparatus using a guide means 10 such as a rail.

  Next, the configuration of the electrophotographic photosensitive member used in the process cartridge of the present invention will be described.

  As an electrophotographic photoreceptor, an electrophotographic photoreceptor having a support and a photosensitive layer provided on the support is generally used.

  The photosensitive layer is separated into a charge generating layer containing a charge generating material and a charge transporting layer containing a charge transporting material even if it is a single layer type photosensitive layer containing the charge transporting material and the charge generating material in the same layer. A laminated type (functional separation type) photosensitive layer may be used, but a laminated type photosensitive layer is preferred from the viewpoint of electrophotographic characteristics. The laminated photosensitive layer has a normal layer type photosensitive layer laminated in the order of the charge generation layer and the charge transport layer from the support side, and a reverse layer type photosensitive layer laminated in the order of the charge transport layer and the charge generation layer from the support side. However, a normal photosensitive layer is preferred from the viewpoint of electrophotographic characteristics.

  As a support body, what is necessary is just to have electroconductivity (conductive support body), for example, metal supports, such as aluminum, an aluminum alloy, and stainless steel, can be used. Moreover, the said metal support body and plastic support body which have the layer in which aluminum, an aluminum alloy, an indium oxide tin oxide alloy etc. were formed into a film by vacuum deposition can also be used. In addition, a support in which conductive particles such as carbon black, tin oxide particles, titanium oxide particles, and silver particles are impregnated into plastic or paper together with an appropriate binder resin, or a plastic support having a conductive binder resin, etc. Can also be used. In addition, examples of the shape of the support include a cylindrical shape and a belt shape, and a cylindrical shape is preferable.

  Between the support and the photosensitive layer (charge generation layer, charge transport layer) or an intermediate layer described later, there is a conductive layer for the purpose of preventing interference fringes due to scattering of laser light or the like and covering the scratches on the support. It may be provided. The conductive layer can be formed by dispersing conductive particles such as carbon black and metal particles in a binder resin. The thickness of the conductive layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  Further, an intermediate layer having a barrier function or an adhesive function may be provided between the support or the conductive layer and the photosensitive layer (charge generation layer, charge transport layer). The intermediate layer is formed for the purpose of improving the adhesion of the photosensitive layer, improving the coating property, improving the charge injection property from the support, and protecting the photosensitive layer from electrical breakdown. The intermediate layer can be formed using materials such as casein resin, polyvinyl alcohol resin, ethyl cellulose resin, ethylene-acrylic acid copolymer, polyamide resin, modified polyamide resin, polyurethane resin, gelatin resin, and aluminum oxide. The thickness of the intermediate layer is preferably 0.05 to 5 μm, and more preferably 0.3 to 1 μm.

  Examples of the charge generating material used in the electrophotographic photosensitive member of the present invention include azo pigments such as monoazo, disazo and trisazo, phthalocyanine pigments such as metal phthalocyanine and nonmetal phthalocyanine, indigo pigments such as indigo and thioindigo, Perylene pigments such as perylene anhydride and perylene imide, polycyclic quinone pigments such as anthraquinone and pyrenequinone, squarylium dyes, pyrylium salts and thiapyrylium salts, triphenylmethane dyes, selenium, selenium-tellurium, amorphous Examples thereof include inorganic substances such as silicon, quinacridone pigments, azulenium salt pigments, cyanine dyes, xanthene dyes, quinoneimine dyes, styryl dyes, cadmium sulfide, and zinc oxide. These charge generation materials may be used alone or in combination of two or more.

  When the photosensitive layer is a laminated photosensitive layer, examples of the binder resin used for the charge generation layer include polycarbonate resin, polyester resin, polyarylate resin, butyral resin, polystyrene resin, polyvinyl acetal resin, diallyl phthalate resin, and acrylic resin. Methacrylic resin, vinyl acetate resin, phenol resin, silicone resin, polysulfone resin, styrene-butadiene copolymer resin, alkyd resin, epoxy resin, urea resin, vinyl chloride-vinyl acetate copolymer resin, and the like. In particular, a butyral resin is preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

  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 binder resin and a solvent and drying the coating solution. Examples of the dispersion method include a method using a homogenizer, an ultrasonic disperser, a ball mill, a sand mill, a roll mill, a vibration mill, an attritor, a liquid collision type high-speed disperser, and the like. The ratio between the charge generating material and the binder resin is preferably in the range of 0.25: 1 to 1.5: 1 (mass ratio).

  The solvent used in the coating solution for the charge generation layer is selected from the solubility and dispersion stability of the binder resin and charge generation material used, and the organic solvents include alcohols, sulfoxides, ketones, ethers, esters, aliphatic halogens. Hydrocarbons and aromatic compounds.

  The thickness of the charge generation layer is preferably 5 μm or less, and more preferably 0.01 to 1 μm.

  In addition, various sensitizers, antioxidants, ultraviolet absorbers, plasticizers, and the like can be added to the charge generation layer as necessary.

  Examples of the charge transport material used in the electrophotographic photoreceptor of the present invention include triarylamine compounds, hydrazone compounds, styryl compounds, stilbene compounds, pyrazoline compounds, oxazole compounds, thiazole compounds, and triarylmethane compounds. These charge transport materials may be used alone or in combination of two or more.

  Note that it is preferable to use a charge transport material having a high oxidation potential in order to prevent the phenomenon of so-called image blur, where the image is crushed and characters cannot be distinguished. The oxidation potential is preferably 0.6 eV or more, more preferably 0.7 eV or more.

  When the photosensitive layer is a laminated photosensitive layer, examples of the binder resin used for the charge transport layer include acrylic resin, methacrylic resin, polyacrylamide resin, acrylonitrile resin, polyamide resin, polyvinyl butyral resin, vinyl chloride resin, vinyl acetate. Examples include resins, phenoxy resins, phenol resins, polystyrene resins, polyester resins, polycarbonate resins, polyarylate resins, polysulfone resins, polyphenylene oxide resins, epoxy resins, polyurethane resins, alkyd resins, and unsaturated resins. In particular, polycarbonate resin, polyarylate resin and the like are preferable. These can be used singly or in combination of two or more as a mixture or copolymer.

  The charge transport layer can be formed by applying a charge transport layer coating solution obtained by dissolving a charge transport material and a binder resin in a solvent and drying it. The ratio of the charge transport material and the binder resin is preferably in the range of 0.1: 1 to 5: 1 (mass ratio).

  Solvents used in the charge transport layer coating solution include ketones such as acetone and methyl ethyl ketone, esters such as methyl acetate and ethyl acetate, aromatic hydrocarbons such as toluene and xylene, ethers such as 1,4-dioxane and tetrahydrofuran, and chlorobenzene. , Hydrocarbons substituted with halogen atoms such as chloroform and carbon tetrachloride are used.

  The thickness of the charge transport layer is preferably 5 to 40 μm, and more preferably 10 to 30 μm.

  In addition, an antioxidant, an ultraviolet absorber, a plasticizer, and the like can be added to the charge transport layer as necessary.

  When the photosensitive layer is a single-layer type photosensitive layer, the single-layer type photosensitive layer is a coating for a single-layer type photosensitive layer obtained by dispersing the charge generation material and the charge transport material together with the binder resin and the solvent. It can be formed by applying a liquid and drying it.

  Further, a protective layer may be provided on the photosensitive layer for the purpose of protecting the photosensitive layer. The protective layer can be formed by applying a protective layer coating solution obtained by dissolving the various binder resins described above in a solvent and drying the coating solution.

  As the binder resin used for the protective layer, for example, phenol resin, acrylic resin, polystyrene resin, polyester resin, polycarbonate resin, polyarylate resin, polysulfone resin, polyphenylene oxide resin, epoxy resin, polyurethane resin, alkyd resin, siloxane resin, Examples thereof include unsaturated resins. In particular, phenol resin, acrylic resin, epoxy resin, polyurethane resin, siloxane resin and the like are preferable.

  The thickness of the protective layer is preferably 0.5 to 7 μm, particularly preferably 0.5 to 5.5 μm.

  When applying the coating liquid for each of the above layers, for example, a coating method such as a dip coating method (a dip coating method), a spray coating method, a spinner coating method, a roller coating method, a Meyer bar coating method, a blade coating method, or the like is used. Can do.

  Of the above layers, the layer serving as the surface layer of the electrophotographic photoreceptor preferably contains fluorine atom-containing resin particles. Examples of the fluorine atom-containing resin include tetrafluoroethylene resin, trifluorinated ethylene chloride resin, hexafluoroethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin and ethylene difluoride dichloride resin, and these Copolymers, fluorine-based graft polymers obtained by copolymerizing macromonomers composed of oligomers having a molecular weight of about 1000 to 10,000 having a polymerizable functional group at one end of each molecular chain, and fluorine-based polymerizable monomers, etc. Is mentioned.

  In addition, the surface layer of the electrophotographic photosensitive member includes an acrylic ester or methacrylic ester in which a silicone unit is grafted on a side chain, and a vinyl polymerizable monomer such as acrylic ester, methacrylic ester or styrene. It is preferable to contain a resin obtained by copolymerization.

  Further, an antioxidant may be contained in the layer that becomes the surface layer of the electrophotographic photosensitive member. Antioxidants include, for example, antioxidants for plastics, rubber, petroleum, fats and oils, and hindered amine compounds and hindered phenol compounds are particularly preferable.

  When the protective layer is provided, the protective layer is the surface layer of the electrophotographic photosensitive member, and when the protective layer is not provided, the photosensitive layer is the surface layer of the electrophotographic photosensitive member. Further, when the photosensitive layer is a surface layer of an electrophotographic photosensitive member, when the photosensitive layer is a single layer type photosensitive layer, the single layer type photosensitive layer is a surface layer of the electrophotographic photosensitive member, and the photosensitive layer is In the case of the normal type photosensitive layer, the charge transport layer is the surface layer of the electrophotographic photosensitive member, and in the case of the reverse layer type photosensitive layer, the charge generating layer is the surface layer of the electrophotographic photosensitive member.

  Next, the configuration of the shutter used in the process cartridge of the present invention will be described.

  The shutter manufacturing method may be the same as the conventional shutter manufacturing method. However, the shutter used in the process cartridge of the present invention needs to move to a position in contact with the electrophotographic photosensitive member in the image forming area of the electrophotographic photosensitive member when the process cartridge is not attached to the main body of the electrophotographic apparatus. The shape of the surface in contact with the electrophotographic photosensitive member is preferably a shape along the shape of the electrophotographic photosensitive member. For example, when the electrophotographic photosensitive member is cylindrical, the shape of the surface of the shutter that comes into contact with the electrophotographic photosensitive member is preferably a shape that matches the curved surface of the surface of the cylindrical electrophotographic photosensitive member.

  The shutter material may be selected so as to satisfy the condition represented by the above formula (1) or the condition represented by the above formula (2), but the main component is preferably a resin such as polypropylene resin. Moreover, you may contain a flame retardant from a safety viewpoint with respect to a fire. Examples of the flame retardant include halogen flame retardants such as bromine flame retardant and chlorine flame retardant, phosphorus flame retardants such as phosphate ester flame retardant, other inorganic flame retardants, polyphenylene ether and the like.

  The flame retardant will be described in more detail. Halogen flame retardants are roughly classified into bromine flame retardants and chlorine flame retardants. Typical brominated flame retardants include tetrabromobisphenol A (TBA), 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, hexabromocyclododecane, tris (2,3- And dibromopropyl) isocyanurate, tribromophenol, decabromodiphenyl oxide, halogen-containing polyphosphate, and the like. Examples of the chlorinated flame retardant include chlorinated paraffin. Phosphorus flame retardants include ammonium phosphate, tricresyl phosphate, trischloroethyl phosphate, tris (β-chloroethyl) phosphate, cresyl diphenyl phosphate, xylenyl diphenyl phosphate, acidic phosphate ester, nitrogen-containing phosphorus compounds, etc. Is mentioned. When the antimony trioxide is used in combination with the brominated flame retardant and the polyphenylene ether is used in combination with the phosphate ester flame retardant, a higher flame retardant effect can be obtained. However, in recent years, inorganic flame retardants other than phosphorus flame retardants and antimony trioxide are preferably used from the viewpoint of the environment. Inorganic flame retardants include red phosphorus, tin oxide, antimony trioxide, zirconium hydroxide, barium metaborate, aluminum hydroxide, magnesium hydroxide, and other chemicals between the layers of natural phosphorus pen graphite. Intercalated (inserted) expanded graphite is also preferably used. In particular, a flame retardant that can also be used as a colorant such as expanded graphite is preferable for parts that require light shielding as in the present invention. Moreover, Si powder which has a methacryl group as a reactive group as a flame retardant is also preferably used. As the flame retardant, those other than those listed above may be used, or two or more kinds may be used in combination.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to these. In the examples, “part” means “part by mass”. Examples 3 and 5-8 are reference examples.

(Measurement method of maximum static friction coefficient)
In the present invention, the maximum static friction coefficient can be measured using a Haydon surface property measuring machine TYPE-14 (manufactured by Shinto Kagaku Co., Ltd.) in a 23 ° C./55% RH environment. Measurements were made using a modified machine modified. A schematic configuration of this measuring machine is shown in FIG.

  As a member to be brought into contact with an object to be measured at the time of measuring the maximum static friction coefficient, a urethane rubber molded into a blade shape (urethane rubber blade 303) was used. The wallet hardness of the urethane rubber blade 303 is 73 °, and the dimensions are 5 mm wide × 10 mm long × 2 mm thick.

  As shown in FIG. 4, the urethane rubber blade 303 is sandwiched between the upper holder 311 and the lower holder 312 in the thickness direction, and is fixed so that the length from the holder is 8 mm in the length direction. The contact angle between the DUT 302 and the urethane rubber blade 303 is set to 22.5 °. Reference numeral 313 denotes a screw.

  Next, an equilibrium is obtained at a position where the DUT 302 and the urethane rubber blade 303 are just in contact, and a weight 306 is placed on the plate 305 and a load is applied. Then, the object 302 to be measured placed on the table 301 is moved at a speed of 100 mm / min in the direction of the arrow in FIG.

  Next, the maximum torque at the moment when the urethane rubber blade 303 starts to move with respect to the object to be measured 302 is converted into a friction force by the mechanism of the load converter 304 via the lateral arm 304 and read.

  Regarding the load on the urethane rubber blade 303, the mass of the weight 306 is changed to 10 g, 20 g, 30 g, 50 g, and 100 g, and the frictional force at each load is measured.

  Before changing the load, the urethane rubber blade 303 is wiped dry with a nonwoven fabric or the like.

The maximum static friction coefficient is generally obtained from the following formula (A), but depending on the shape of the object to be measured 302, the frictional force changes even with the same load.
Maximum static friction coefficient (*) = Friction force / Load (A)
Therefore, as shown by the following formula (B), the maximum static friction coefficient (*) obtained from the above formula (A) is divided by the maximum static friction coefficient of the standard substance, and this value is the maximum static friction coefficient in the present invention. It was.

Maximum static friction coefficient in the present invention = maximum static friction coefficient (*) ÷ maximum static friction coefficient of reference material (B)
As the standard substance, a polyethylene terephthalate film (PET film) having a thickness of 20 to 300 μm was used. When the object to be measured for the maximum static friction coefficient is an electrophotographic photosensitive member, the PET film is wound around a member having the same shape as the electrophotographic photosensitive member so as not to have wrinkles or slack. When the object to be measured for static friction coefficient measurement is a shutter, the maximum static friction is the same as the object to be measured for the PET film wrapped around the same shape as the shutter so that there is no wrinkle or slack. The coefficient was measured.

In this way, the maximum static friction coefficient F _{(S) of} the shutter and the maximum static friction coefficient F _(D) of the surface of the electrophotographic photosensitive member were obtained.

  3 and 4 are summarized as follows: 301 is a table on which an object 302 is placed; 302 is an object to be measured; 303 is a urethane rubber blade; 304 is a horizontal arm; 305 is a plate on which a weight 306 is placed; Is a weight, 307 is a vertical arm, 308 is a balance weight, 309 is a load converter, 310 is a table moving device, 311 is an upper holder, 312 is a lower holder, and 313 is a screw.

(Measurement method of universal hardness HU and elastic deformation rate We%)
In the present invention, the universal hardness HU and the elastic deformation ratio We% are modified machines in which the table for the object to be measured of the hardness scale Fisherscope H100 (manufactured by Fischer, Germany) is remodeled in an environment of 23 ° C./55% RH. It measured using. A schematic configuration of this measuring machine is shown in FIG. FIG. 5 shows an electrophotographic photoreceptor 501 using an aluminum cylinder as a support as an example of the object to be measured. Reference numeral 502 denotes a mount for the electrophotographic photosensitive member 501, 503 denotes an indenter, 504 denotes a movable table, and 505 denotes a microscope position.

  The measurement method employed by the present invention can measure the hardness of thin films, cured films, organic films, etc., and if the thickness / film thickness of the object to be measured is 10 μm or more, it is not affected by the base, Whether it is a shutter that is often the main component or an electrophotographic photosensitive member in which a resin film is formed on a metal support such as aluminum, it can be measured and evaluated under the same conditions. .

  As the indenter 503, a diamond indenter having a quadrangular pyramid shape and a facing angle of 136 ° was used. When the indenter 503 is pushed into the object to be measured while applying a load, the indentation depth h with the load applied is electrically detected and read.

As shown in the following formula (C), the universal hardness HU is a surface area S of an indentation (calculated from the geometric shape of the indenter) on the measurement object caused by the load F [N] applied to the indenter. It is the value divided by [mm ² ].

Universal hardness HU [N / mm ² ] = load F [N] ÷ indenter surface area S [mm ² ] = load F [N] / (26.43 × (indentation depth h under load h [ mm]) ² ) (C)
A measurement example of universal hardness is shown in FIG. The horizontal axis of the graph of FIG. 6 is the indentation depth h [× 10 ⁻³ mm], and the vertical axis is the load F [× 10 ⁻³ N].

  The elastic deformation rate We% is obtained as follows.

  That is, the indenter 503 to which a load is applied is pushed into the object to be measured to a depth of 1 μm, and then the indentation depth and the load until the load becomes zero are measured by reducing the load. In FIG. 6 of the example, A → B → C. Further, the elastic deformation work We [nJ] is represented by an area surrounded by C-B-D-C in FIG. 6, and the plastic deformation work Wr [nJ] is A-B-C in FIG. It is represented by the area surrounded by -A. By substituting these elastic deformation work We and plastic deformation work Wr into the following equation (D), the elastic deformation rate We% is obtained.

Elastic deformation rate We% [%] = {elastic deformation work We [nJ] ÷ (elastic deformation work We [nJ] + plastic deformation work Wr [nJ])} × 100 (D)
Thus, the universal hardness HU _(S) [N / mm ² ] of the shutter, the universal hardness HU _(D) [N / mm ² ] of the surface of the electrophotographic photosensitive member, and the elastic deformation rate We% _{(S) of the} shutter. [%] And the elastic deformation rate We% _(D) [%] of the surface of the electrophotographic photosensitive member were obtained.

Example 1
-Preparation of electrophotographic photosensitive member An aluminum cylinder having a diameter of 30.0 mm and a length of 260.5 mm was used as a support.

  Next, a 5% by mass methanol solution of polyamide resin (trade name: Amilan CM8000, manufactured by Toray Industries, Inc.) was prepared as an intermediate layer coating solution, and this intermediate layer coating solution was dip coated on the support. This was dried at 90 ° C. for 10 minutes (hot air drying) to form an intermediate layer having a thickness of 0.5 μm.

  Next, 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 4 parts of a crystalline form of hydroxygallium phthalocyanine (charge generating substance) having 2 parts, 2 parts of polyvinyl butyral resin (trade name: BX-1, manufactured by Sekisui Chemical Co., Ltd.) and 80 parts of cyclohexanone were used with glass beads having a diameter of 1 mm. A charge generation layer coating solution was prepared by dispersing for 4 hours in a sand mill.

X-ray diffraction was measured using CuKα rays under the following conditions.
Measuring instrument: Fully automatic X-ray diffractometer MXP18 manufactured by Mac Science
X-ray tube: Cu
Tube voltage: 50 kV
Tube current: 300mA
Scan method: 2θ / θ scan Scan speed: 2 deg. / Min
Sampling interval: 0.020 deg.
Start angle (2θ): 5 deg.
Stop angle (2θ): 40 deg.
Divergence slit: 0.5 deg.
Scattering slit: 0.5 deg.
Receiving slit: 0.3mm
Using a curved monochromator This charge generation layer coating solution was dip coated on the intermediate layer and dried at 100 ° C. for 10 minutes (hot air drying) to form a charge generation layer having a thickness of 0.2 μm. .

  Next, 8 parts of a compound (charge transport material) having a structure represented by the following formula:

2 parts of a compound (charge transport material) having a structure represented by the following formula,

And 10 parts of polycarbonate resin (trade name: Iupilon Z-200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was dissolved in 100 parts of monochlorobenzene to prepare a coating solution for charge transport layer.

  This charge transport layer coating solution was dip-coated on the charge generation layer and dried at 105 ° C. for 1 hour to form a charge transport layer having a thickness of 21 μm.

  Next, an epoxy compound having a structure represented by the following formula at a ratio of 15% of the number of phenolic hydroxyl groups of the phenol-aldehyde resol resin (prepolymer of phenol resin)

And 10 parts of an epoxy-modified phenolic resin obtained by adding the compound, and 7 parts of a compound (charge transport material) having a structure represented by the following formula

Was dissolved in 40 parts of ethyl alcohol to prepare a coating solution for a protective layer (second charge transport layer).

  This coating solution for the protective layer (second charge transport layer) is dip-coated on the charge transport layer and dried (thermoset) at 145 ° C. for 1 hour to thereby form a protective layer (second layer) having a thickness of 3 μm. A coating solution for charge transport layer) was formed.

  In this way, a cylindrical electrophotographic photosensitive member having a protective layer (second charge transport layer) as a surface layer was produced.

Table 1 shows the maximum static friction coefficient, universal hardness HU _(D), and elastic deformation rate We% _(D) of the surface of the electrophotographic photosensitive member produced. In addition, the measurement of each physical property was performed 5 times and each took the average.

-Preparation of shutter A shutter was prepared by an injection molding method using a resin composition in which 11.5 parts of cresyl diphenyl phosphate (a flame retardant) was added to 100 parts of polypropylene resin as a shutter material.

  Regarding the shape of the shutter, the surface on the side in contact with the electrophotographic photosensitive member is a curved surface matching the curved surface of the surface of the electrophotographic photosensitive member, and the opposite surface is on the side in contact with the electrophotographic photosensitive member. It is a curved surface concentric with the surface. The thickness of the shutter was 0.8 mm.

Table 1 shows the maximum static friction coefficient, universal hardness HU _(S), and elastic deformation rate We% _(S) of the manufactured shutter. In addition, the measurement of each physical property was performed 5 times and each took the average.

Production of process cartridge A process cartridge having the structure shown in FIG. 1 was produced using the electrophotographic photosensitive member and the shutter. The manufactured process cartridge moves to a position where the shutter is in contact with the electrophotographic photosensitive member in the image forming area of the electrophotographic photosensitive member when the process cartridge is not attached to the main body of the electrophotographic photosensitive member. When it is mounted, the electrophotographic photosensitive member is moved to an open position in order to open it.

  Further, the portion where the electrophotographic photosensitive member and the shutter are in contact is marked in advance so that it can be identified later.

-Evaluation First, the produced process cartridge was put in the resin bag, and it accommodated in the box of the corrugated cardboard with the packing material. 20 pieces of the same were prepared. These were left for 15 hours in an environment of 45 ° C./10% RH.

  Next, 20 boxes containing process cartridges were dropped 30 times from a height of 100 cm in that environment. The process cartridge that gave the fall history was removed from the box and bag.

  Further, a laser beam printer / laser jet 4000 (evaluator) manufactured by Hewlett-Packard Co. was left in an environment of 45 ° C./10% RH for 20 hours.

  Next, the process cartridge which has been allowed to stand for 15 hours in an environment of 45 ° C./10% RH and given a fall history is mounted on the laser beam printer which has been left for 20 hours in an environment of 45 ° C./10% RH. The output image was evaluated as follows.

  First, one halftone image by laser emission of one dot and one space in A4 size and one solid black image of full emission were output (initial).

  Next, 5000 A4 size horizontal line images with a printing ratio of 2% were output in an intermittent mode (a mode in which the printing is stopped for 1 second after one printing and the next printing is performed). After outputting 5000 sheets, one halftone image and one solid black image were output in the same manner as described above.

  For the halftone image and solid black image after the initial output and 5000 sheets, the density difference between the part where the electrophotographic photosensitive member and the shutter were in contact with each other when the process cartridge was given a fall history It was visually determined whether there was any. Further, whether or not the electrophotographic photosensitive member was damaged due to friction between the electrophotographic photosensitive member and the shutter was visually determined from the output image.

  Of the 20 process cartridges evaluated, those having an image defect due to a density difference or a flaw in the output image were counted. That is, the smaller the count, the better. The evaluation results are shown in Table 1.

(Example 2)
In Example 1, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 1 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Preparation of electrophotographic photoreceptor In Example 1, the temperature when drying (thermosetting) the coating solution for the protective layer (second charge transport layer) dip-coated on the charge transport layer was changed from 145 ° C to 155 ° C. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that.

-Production of shutter A shutter was produced in the same manner as in Example 1 except that the polypropylene resin as a material was changed to polyethylene resin.

(Example 3)
In Example 1, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 1 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Preparation of electrophotographic photosensitive member An aluminum cylinder having a diameter of 30.0 mm and a length of 260.5 mm was used as a support.

  Next, this support was immersed in nitric acid and washed with water, and an anodized film having a thickness of 7 μm was formed on the support using sulfuric acid as an electrolyte. This was washed with water, sealed with nickel acetate as a sealing agent, washed with water, immersed in hot water and dried.

  Next, 10 parts of crystalline oxytitanium phthalocyanine (charge generating substance) having strong peaks at 9.5 °, 24.1 °, and 27.3 ° with a Bragg angle 2θ ± 0.2 ° in CuKα characteristic X-ray diffraction To this, 200 parts of n-propanol was added, followed by pulverization and atomization dispersion treatment. A 10% n-propanol solution containing 5 parts of polyvinyl butyral resin (trade name: Denka Butyral # -6000, manufactured by Denki Kagaku Kogyo Co., Ltd.) was added thereto to prepare a charge generation layer coating solution.

  The charge generation layer coating solution is dip coated on the anodized film after the sealing treatment, and dried at 100 ° C. for 10 minutes (hot air drying), thereby forming a charge generation layer having a thickness of 0.2 μm. Formed.

  Next, 60 parts of a compound (charge transport material) having a structure represented by the following formula:

5 parts of a compound (charge transport material) having a structure represented by the following formula:

And 100 parts of polycarbonate resins (trade name: Iupilon Z-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) were dissolved in 1000 parts of 1,4-dioxane to prepare a charge transport layer coating solution.

  The charge transport layer coating solution was dip-coated on the charge generation layer and dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 21 μm.

  In this way, a cylindrical electrophotographic photosensitive member having a charge transport layer as a surface layer was produced.

-Production of shutter A shutter was produced in the same manner as in Example 1 except that the flame retardant of the material was changed from 11.5 parts of cresyl diphenyl phosphate to 15 parts of triphenyl phosphate.

Example 4
In Example 3, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 3 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Preparation of electrophotographic photosensitive member In Example 3, polycarbonate resin (trade name: Iupilon Z-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) in the charge transport layer coating solution was converted to polycarbonate resin (trade name: Iupilon Z-800). (Mitsubishi Gas Chemical Co., Ltd.) and similar to Example 3 except that the temperature for drying the charge transport layer coating solution dip coated on the charge generation layer was changed from 110 ° C. to 95 ° C. Thus, an electrophotographic photosensitive member was produced.

-Production of shutter A shutter was produced in the same manner as in Example 3, except that the material flame retardant was changed from 15 parts of triphenyl phosphate to 10 parts of octyl diphenyl phosphate and 10 parts of polyphenylene ether.

(Example 5)
In Example 1, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 1 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Production of electrophotographic photoreceptor An electrophotographic photoreceptor was produced in the same manner as in Example 1 except that the protective layer (second charge transport layer) was not provided. That is, the surface layer is a charge transport layer.

-Production of shutter A shutter was produced in the same manner as in Example 1 except that the flame retardant of the material was changed from 11.5 parts of cresyl diphenyl phosphate to 9 parts of triethyl phosphate.

(Example 6)
In Example 5, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 5 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Preparation of electrophotographic photoreceptor In Example 5, except that the temperature for drying the charge transport layer coating solution dip-coated on the charge generation layer was changed from 105 ° C to 115 ° C. Thus, an electrophotographic photosensitive member was produced.

-Production of shutter A shutter was produced in the same manner as in Example 1 except that the material flame retardant was changed from 9 parts of triethyl phosphate to 10 parts of expanded graphite.

(Example 7)
In Example 3, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 3 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Preparation of electrophotographic photosensitive member In Example 3, 52 parts of a compound (charge transporting substance) having a structure represented by the following formula is used as the charge transporting substance (65 parts in total) in the coating liquid for charge transporting layer

3 parts of a compound (charge transport material) having a structure represented by the following formula,

And 10 parts of a compound (charge transport material) having a structure represented by the following formula

An electrophotographic photosensitive member was produced in the same manner as in Example 3 except that the above was changed.

-Preparation of shutter In Example 3, the flame retardant of the material was changed from 15 parts of triphenyl phosphate to 11.5 parts of melamine polyphosphate, and 0.2 parts of polytetrafluoroethylene resin particles with respect to 100 parts of polypropylene resin. A shutter was produced in the same manner as in Example 3 except for the addition.

(Example 8)
In Example 1, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 1 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Preparation of electrophotographic photosensitive member In Example 1, the amount of the epoxy-modified phenol resin in the coating solution for the protective layer (second charge transport layer) was changed from 10 parts to 5 parts, and dip coated on the charge transport layer. An electrophotographic photosensitive member was produced in the same manner as in Example 1 except that the temperature for drying (thermosetting) the coating solution for the protective layer (second charge transport layer) was changed from 145 ° C. to 140 ° C.

-Production of shutter A shutter was produced in the same manner as in Example 1, except that the material flame retardant was changed from 11.5 parts of cresyl diphenyl phosphate to 18 parts of ammonium phosphate.

Example 9
In Example 1, except that the thickness of the shutter was changed from 0.8 mm to 1.1 mm, an electrophotographic photosensitive member, a shutter, and a process cartridge were produced and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Example 10)
In Example 4, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 4 except that the thickness of the shutter was changed from 0.8 mm to 1.1 mm. The evaluation results are shown in Table 1.

(Comparative Example 1)
In Example 3, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 3 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Production of electrophotographic photosensitive member An electrophotographic photosensitive member was produced in the same manner as in Example 3, except that the charge transport layer was formed as follows.

  That is, 75 parts of a compound (charge transport material) having a structure represented by the following formula:

And 100 parts of polycarbonate resins (trade name: Iupilon Z-200, manufactured by Mitsubishi Gas Chemical Co., Ltd.) were dissolved in 1000 parts of 1,4-dioxane to prepare a coating solution for a charge transport layer.

  The charge transport layer coating solution was dip-coated on the charge generation layer and dried at 110 ° C. for 1 hour to form a charge transport layer having a thickness of 21 μm.

-Production of shutter In Example 3, the material was changed from polypropylene resin to melamine resin, and the amount of the flame retardant triphenyl phosphate was changed from 15 parts to 11.5 parts. Was made.

(Comparative Example 2)
In Example 4, an electrophotographic photosensitive member, a shutter, and a process cartridge were produced and evaluated in the same manner as in Example 4 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Preparation of electrophotographic photosensitive member In Example 4, 100 parts of polycarbonate resin (trade name: Iupilon Z-800, manufactured by Mitsubishi Gas Chemical Co., Ltd.) in the coating solution for the charge transport layer was converted to polycarbonate resin (trade name: Iupilon Z). -050, Mitsubishi Gas Chemical Co., Ltd.) 20 parts and polycarbonate resin (trade name: Iupilon Z-200, Mitsubishi Gas Chemical Co., Ltd.) 100 parts, charge transport layer dip coated on the charge generation layer An electrophotographic photosensitive member was produced in the same manner as in Example 4 except that the temperature at which the coating liquid for drying was changed from 95 ° C. to 120 ° C.

-Preparation of shutter In Example 4, except that the polypropylene resin of the material was changed to a phenol resin, and the flame retardant of the material was changed from 10 parts of octyl diphenyl phosphate and 10 parts of polyphenylene ether to 11.5 parts of cresyl diphenyl phosphate, A shutter was produced in the same manner as in Example 4.

(Comparative Example 3)
In Example 3, an electrophotographic photosensitive member, a shutter, and a process cartridge were prepared and evaluated in the same manner as in Example 3 except that the electrophotographic photosensitive member and the shutter were changed as follows. The evaluation results are shown in Table 1.

-Production of electrophotographic photosensitive member An electrophotographic photosensitive member was produced in the same manner as in Example 3, except that the charge transport layer was formed as follows.

  That is, 50 parts of a compound (charge transport material) having a structure represented by the following formula:

15 parts of a compound (charge transport material) having a structure represented by the following formula,

And 100 parts of polycarbonate resins (trade name: Iupilon Z-400, manufactured by Mitsubishi Gas Chemical Co., Ltd.) were dissolved in 1000 parts of 1,4-dioxane to prepare a charge transport layer coating solution.

  This charge transport layer coating solution was dip-coated on the charge generation layer and dried at 135 ° C. for 1 hour to form a charge transport layer having a thickness of 21 μm.

-Preparation of shutter In Example 3, the material was changed from polypropylene resin to polystyrene resin, and the amount of flame retardant triphenyl phosphate was changed from 15 parts to 11.5 parts. Was made.

The viscosity average molecular weight (Mv) of the polycarbonate resin manufactured by Mitsubishi Gas Chemical Co., Ltd. used in this example and the comparative example is as follows.
Product Name: Iupilon Z-050 Mv = 5.50 × 10 ³
Product name: Iupilon Z-200 Mv = 2.12 × 10 ⁴
Product name: Iupilon Z-400 Mv = 4.00 × 10 ⁴
Product name: Iupilon Z-800 Mv = 7.92 × 10 ⁴

It is a figure which shows an example of schematic structure of the process cartridge of this invention. FIG. 2 is a diagram illustrating an example of a schematic configuration of an electrophotographic apparatus in which the process cartridge having the configuration illustrated in FIG. 1 is mounted. It is a figure which shows schematic structure of the measuring machine of a maximum static friction coefficient. It is a figure which shows schematic structure of the holder which clamps a urethane rubber blade. It is a figure which shows schematic structure of the measuring machine of universal hardness HU and elastic deformation rate We%. It is a figure which shows the example of a measurement of universal hardness.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrophotographic photoreceptor 2 Axis 3 Charging means 4 Exposure light 5s Toner carrier 5t Toner 6 Transfer means 7 Cleaning means 8 Fixing means 9 Frame body 10 Guide means 20 Shutter 20 'When the process cartridge is mounted on the electrophotographic apparatus main body The position at which the shutter moves P Transfer material 301 Table 302 Object to be measured 303 Urethane rubber blade 304 Horizontal arm 305 Dish 306 Weight 307 Vertical arm 308 Balance weight 309 Load converter 310 Stand moving device 311 Upper holder 312 Lower holder 313 Screw 501 Electron Photosensitive member 502 Placement table 503 Indenter 504 Moving table 505 Microscope position

Claims (4)

A process cartridge that integrally supports an electrophotographic photosensitive member and at least one means selected from the group consisting of a charging means, a developing means, a transfer means, and a cleaning means, and is detachable from the electrophotographic apparatus main body,
A shutter for protecting the electrophotographic photosensitive member;
The shutter moves to a position in contact with the electrophotographic photosensitive member in the image forming area of the electrophotographic photosensitive member when the process cartridge is not attached to the main body of the electrophotographic photosensitive member. A shutter that moves to an open position to open the electrophotographic photoreceptor when mounted;
The elastic deformation rate of the shutter is 48% or more and 53% or less,
F _(S) is the maximum coefficient of static friction of the shutter when measured with a urethane rubber blade having a Wallace hardness of 73 ° and a dimension of 5 mm wide × 10 mm long × 2 mm thick in contact with the shutter. The maximum surface of the electrophotographic photosensitive member when measured by bringing a urethane rubber blade having a Wallace hardness of 73 ° and dimensions of 5 mm in width × 10 mm in length × 2 mm in thickness into contact with the electrophotographic photosensitive member. A process cartridge characterized by satisfying a condition represented by the following formula (1) or a condition represented by the following formula (2) when the static friction coefficient is F _(D) .
F _(S) × F _(D) ≦ 0.85 (1)
F _(S) × F _(D) ≧ 1.25 (2) F _(S) is the maximum coefficient of static friction of the shutter when measured with a urethane rubber blade having a Wallace hardness of 73 °, a width of 5 mm, a length of 10 mm, and a thickness of 2 mm in contact with the shutter. The maximum surface of the electrophotographic photosensitive member measured when a urethane rubber blade having a Wallace hardness of 73 ° and a dimension of 5 mm wide × 10 mm long × 2 mm thick is brought into contact with the electrophotographic photosensitive member. 2. The process cartridge according to claim 1, wherein when the static friction coefficient is F _(D) , the condition represented by the following formula (3) or the condition represented by the following formula (4) is satisfied.
F _(S) × F _(D) ≦ 0.65 (3)
F _(S) × F _(D) ≧ 1.50 (4) A process cartridge according to claim 1 or 2 the thickness of the shutter is 1mm or more. Electrophotographic apparatus comprising: a process cartridge according to any one of claims 1-3.

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