Abstract: An electrophotographic image forming system forms an electrostatic latent image on at least a photoreceptor, develops an image using an electrostatic charge image developing toner, and removes the toner using a cleaning blade. A tip ridge of the cleaning blade is pressed against a surface of the photoreceptor. The system includes a photosensitive layer of the photoreceptor and a surface protecting layer that is provided on a surface of the photosensitive layer. The surface protecting layer includes a polymerizable monomer having at least two polymerizable groups in a molecule and a polymer of a hole transporting compound having a polymerizable group represented by General formula (1). The tip ridge of the cleaning blade has an edge angle that is obtuse and less than 120° and is pressed against the surface of the photoreceptor at an effective contact angle that is in a range of 8 to 20°.

Abstract: An imaging system includes a belt roller extending in an axial direction, an endless belt to rotate about the belt roller, a steering roller located inside the endless belt and extending in the axial direction, a steering roller actuator located at an end portion of the belt roller in the axial direction to contact the endless belt, and a support. The steering roller actuator is displaceable in the axial direction in response to a shifting of the endless belt so as to tilt the steering roller with respect to the axial direction. The support supports the endless belt in a gap formed between the belt roller and the steering roller actuator when the steering roller actuator is displaced in the axial direction.

Abstract: The object of the present invention is to provide a decorative film excellent in moldability and tensile strength; and a method for producing a three-dimensionally molded article with a decorative film. The decorative film of the present invention is used for decorating a three-dimensionally molded article. It is a decorative film comprising at least a substrate film layer and a clear layer, wherein the clear layer is made of a fluorinated polymer comprising units based on a fluoroolefin, units based on a monomer having no crosslinkable group, which is at least one member selected from the group consisting of a vinyl ether, a vinyl ester, an allyl ether, an allyl ester and a (meth)acrylic acid ester, and units having a crosslinkable group; and the content of the units based on a fluoroolefin is from 20 to 70 mol % to all units which the fluorinated polymer comprises.

Abstract: A process cartridge removably disposed in an imaging device provided with a rotational force output head. The process cartridge (100) includes a cartridge body, a rotation component having a rotation axis L1, and a driving force receiving assembly. The driving force receiving assembly is disposed at an end of the cartridge body, and includes a rotational force receiving member and a position adjusting mechanism. The rotational force receiving member is provided with a rotational force receiving portion, a connection portion, and a rotational force transmitting portion. The position adjusting mechanism enables the rotational force receiving member to rotate in a preset direction.

Abstract: In a photosensitive drum, a drum flange is press-fitted to each end of a drum element tube. The drum flange includes a flange facing the drum element tube, and a press-in boss formed on a drum-facing surface side of the flange and press-fitted to the inner circumferential side of the drum element tube. The outer circumferential surface of the press-in boss is configured so that partial cylindrical surfaces to be in contact with the inner circumferential surface of the drum element tube and oppositely-facing partial cylindrical surfaces not to be in contact with the inner circumferential surface of the drum element tube are alternately formed along the circumferential direction. First openings formed to penetrate at least a part of the press-in boss are respectively provided on the proximal end side of the partial cylindrical surfaces in the press-in boss.

Abstract: A driving device for photosensitive members and developing rollers includes a clutch for selectively transmitting a rotational force from a driving source to the rollers. The clutch includes a rotatable driving member having a first engaging portion together with the first portion, a follower having a second engaging portion engageable with the first portion, and a rotatable member changeable, by rotation in a direction opposite from a rotational direction of the driving member, from a first state in which the driving force from the driving source is not transmitted without engagement between the first portion and the second engaging portion to a second state in which the rotor rotates by engagement therebetween. The rotor urges the follower in the opposite direction when the first engageable member and the second engageable member are not engaged with each other, by the opposite rotation.

Abstract: Provided are a developing roller which includes a shaft, and a base layer and a surface layer sequentially formed on an outer peripheral portion of the shaft in a radial direction, where 1) a low-resilience layer is disposed between the base layer and the surface layer, 2) the low-resilience layer has a loss tangent tan ? value that is larger than a loss tangent tan ? value of any of the base layer and the surface layer when measured under conditions of a temperature of 23° C., an amplitude of ±20 ?m, and a frequency of 6 Hz, and 3) the developing roller has an Asker C hardness and thickness value of 500 or less, which is defined by the following formula (1): Asker C hardness and thickness value of the developing roller=Asker C hardness of the developing roller×(thickness of the developing roller+6)??(1).

Abstract: An image forming apparatus includes a photoconductor, light emitting elements, a developing device, a fixing device, and a controller. The photoconductor is charged. The light emitting elements form light spots on the photoconductor in order to form an electrostatic latent image on the photoconductor, and are provided to have a first distance with each other in a main scanning direction. The developing device develops an electrostatic latent image on the photoconductor to a toner image. The fixing device fixes the toner image to a sheet. The controller causes the light emitting elements to form first light spots on the photoconductor, causes the photoconductor to move toward the light emitting elements by a second distance shorter than the first distance in a sub-scanning direction orthogonal to the main scanning direction, and causes the light emitting elements to form second light spots on the photoconductor.

Abstract: Provided is an electrophotographic photoreceptor, which is excellent in abrasion resistance and scratch resistance, has excellent electrical characteristics, and is capable of inhibiting an image defect, a manufacturing method of an electrophotographic photoreceptor, a process cartridge, and an electrophotographic apparatus. A surface layer of the electrophotographic photoreceptor contains a copolymer of a composition which contains resin particles containing fluorine atoms, a charge transport compound having 2 or more polymerizable functional groups, a compound represented by General Formula (1), and a resin having a structure represented by General Formula (2) and a structure represented by General Formula (3). The polymerizable functional groups t are independently selected from an acryloyloxy group and a methacryloyloxy group, and a content of the compound represented by General Formula (1) in the composition is 0.10% by mass or more.

Abstract: An image forming apparatus includes a plurality of image bearers and a rotatable transferor. Images borne on the plurality of image bearers are transferred to the transferor. The transferor has an elastic power larger than an elastic power of each of the plurality of image bearers, and a difference in elastic power between the transferor and a most upstream image bearer in a rotation direction of the transferor is smaller than a difference in elastic power between the transferor and any other image bearer except the most upstream image bearer of the plurality of image bearers.

Abstract: Various variable gloss reduction techniques are disclosed. In one embodiment, a gloss reduction technique is disclosed using a textured roller and a wiper impregnated with fuser oil to create a differential gloss pattern that reduces the gloss of an image printed on a substrate. In one embodiment, a gloss reduction technique is disclosed using a combination of heat and pressure to create a differential gloss pattern that reduces the gloss in specific regions of an image printed on a substrate. In one embodiment, a gloss reduction technique is disclosed using a differential gloss pattern to generate a security mark on a printed image to prevent against copying or fraudulent misrepresentation of the image.

Abstract: An electrophotographic photosensitive member includes, in sequence, a support, a conductive layer, an undercoat layer, a charge generation layer, and a charge transport layer. The conductive layer is a cured film, and the cured film contains titanium oxide particles doped with niobium. The undercoat layer contains a cured product of a composition that contains an electron transport material having a polymerizable functional group and a resin functionalized with a carboxylic acid derivative.

Abstract: The present disclosure provides an electrophotographic photosensitive member that reduces the accumulation of charge and the leakage which are caused by a repeated use in a long period of time. The electrophotographic photosensitive member has a support, an undercoat layer, a charge generation layer and a charge transport layer in this order, wherein the undercoat layer contains a polyamide resin, and a titanium oxide particle, wherein the titanium oxide particle has been surfacetreated with an organosilicon compound, wherein the undercoat layer satisfies 10???70, where ? represents a degree [%] of hydrophobicity of the titanium oxide particle which has been surfacetreated with the organosilicon compound; and the undercoat layer satisfies 0.015?(?×?)?0.040, where ? represents an average primary particle size [?m] of the titanium oxide particles, and ? represents a weight percentage [wt %] of an Si element of the organosilicon compound with respect to the titanium oxide particle.

Abstract: A method for producing an electrophotographic photosensitive member having a photosensitive layer and a protective layer above a support in this order includes: forming a coating film for a protective layer by coating a coating liquid for the protective layer for forming the protective layer on the photosensitive layer and curing the coating film for the protective layer, in which the coating liquid for the protective layer contains a solvent, a compound represented by a general formula (1), a compound represented by a general formula (2), and a compound represented by a general formula (3) at a specific ratio. In addition, in an electrophotographic photosensitive member having a photosensitive layer and a protective layer above a support in this order, the protective layer is obtained by curing a coating liquid for the protective layer.

Abstract: A charging roller for an image forming apparatus is provided, which includes a shaft, an elastic layer disposed around the shaft, and a coating layer formed on the elastic layer, wherein the coating layer includes a urethane resin formed by crosslinking of a polyol mixture with polyisocyanate, and the polyol mixture includes polyester polyol and polyether polyol having 60% by weight or more and 90% by weight or less of an ethylene oxide content.

Abstract: To provide an electrophotographic photosensitive member which does not cause film exfoliation in long-term use. An electrophotographic photosensitive member, having: a support; a layered photosensitive layer; and a protective layer in this order, wherein the protective layer is a single layer, the protective layer includes: at least two specific structures, the two specific structures are included in the protective layer at a mass ratio of 20% or more and 240% or less, and a peak area based on in-plane deformation vibration of terminal olefin (CH2?) of the protective layer and a peak area based on stretching vibration of C?O of acryloyloxy groups, the peak areas being determined by total reflection Fourier transform infrared spectroscopy under conditions where an internal reflection element is Ge, and an incidence angle is 45°, have a fixed relationship.

Abstract: A photosensitive drum is rotatably supported in a main body. A developing cartridge is detachably mountable on the main body in a state where the photosensitive drum is supported in the main body. The developing cartridge includes a developing device and a frame. The developing device includes a developing roller disposed in confrontation with the photosensitive drum to supply developer to the photosensitive drum when the developing cartridge is mounted in the main body, and a developer-accommodating portion configured to accommodate developer. The frame includes a waste-developer-accommodating portion configured to accommodate waste developer and supports the developing device that is movable relative to the frame. The frame is disposed on an opposite side of the developing roller from the photosensitive drum. An urging member is disposed between the frame and the developing device to urge the developing roller toward the photosensitive drum.

Abstract: In one example, a system for transferring an image from a photoconductor to a print substrate includes a transfer member having a removable blanket wrapped around a rotatable drum and a laser. The blanket has a light absorbing exterior surface to receive a liquid LEP ink image from the photoconductor and to release a layer of molten toner to a print substrate. As the drum rotates, the laser exposes a width of the exterior surface of the blanket carrying a liquid LEP ink image to a beam of coherent light that delivers enough power to transform the liquid LEP ink image into molten toner.

Abstract: An electrophotographic photosensitive member (1) includes a conductive substrate (2) and a photosensitive layer (3). The photosensitive layer (3) is a single-layer photosensitive layer (3c) and contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The binder resin includes a polyarylate resin represented by general formula (1). In general formula (1), Q1, Q2, Q3, and Q4 each represent a methyl group or a hydrogen atom. r, s, t, and u each represent a number greater than or equal to 15 and less than or equal to 35.

Abstract: Provided is a toner including a crystalline polyester resin including a constitutional unit derived from saturated aliphatic dicarboxylic acid and a constitutional unit derived from saturated aliphatic diol, an amorphous hybrid resin, an amorphous polyester resin, a release agent, and a colorant, wherein the crystalline polyester resin includes a constitutional unit derived from sebacic acid as the constitutional unit derived from the saturated aliphatic dicarboxylic acid, and the amorphous hybrid resin is a composite resin including a polyester-based resin unit and a styrene-based resin unit.

Abstract: An electrophotographic photosensitive member (1) includes a conductive substrate (2) and a photosensitive layer (3). The photosensitive layer (3) is a single-layer photosensitive layer (3c) containing a charge generating material and an electron transport material. The electron transport material includes a compound represented by general formula (1) shown below. An amount of charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer (3) is at least +7.0 ?C/g. In general formula (1), R1 and R2 each represent, independently of each other, a halogen atom, for example. Further, m, n, and Y are as described in the description.

Abstract: An electrically conductive support for use in an electrophotographic photoreceptor includes a cylindrical main body having a first end and a second end opposite to the first end in an axial direction of the main body. The main body contains an aluminum alloy and has an internal stress in a range of ?30 MPa to 5 MPa. A method of producing the electrically conductive support includes preparing a substrate containing an aluminum alloy obtained at least through an extrusion step, and heat treating the substrate to obtain the electrically conductive support. The heat treating is carried out such that, when a temperature of the heat treating is defined as T (° C.) and a time of the heat treating is defined as H (hours), an amount of the heat treating Q defined by Q=T×H is 800 or less.

Abstract: A cleaning blade, which is to be brought into contact with a surface of a photosensitive drum, satisfies the following condition. First, the cleaning blade having a free length of 8 mm is brought into contact with an opposed object for measurement having a plurality of measurement recesses each having a partially spherical shape with a depth of 0.7 ?m and a radius of 15 ?m on a surface so that a linear pressure is 0.196 N/cm and 0.490 N/cm, and a contact angle with respect to the opposed object for measurement is 25°. In this case, a contact width of the cleaning blade in each of the measurement recesses is 4 ?m or more and 8 ?m or less when the linear pressure is 0.196 N/cm and is 4 ?m or more and 13.5 ?m or less when the linear pressure is 0.490 N/cm.

Abstract: An electrophotographic photosensitive member includes a conductive substrate and a single-layer photosensitive layer. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, an additive, and a binder resin. An optical response time is in a range from 0.05 milliseconds to 0.85 milliseconds. The optical response time is a time from irradiation of a surface of the photosensitive layer charged to +800 V with pulse light having a wavelength of 780 nm to surface potential decay of the photosensitive layer from +800 V to +400 V. An optical intensity of the pulse light is set so that the surface potential of the photosensitive layer becomes +200 V from +800 V after 400 milliseconds from pulse light irradiation of the surface of the photosensitive layer charged to the +800 V. The additive includes either of both an ultraviolet absorbing agent and an antioxidant.

Abstract: An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer having a single-layer structure. The photosensitive layer contains a charge generating material, an electron transport material, a polycarbonate resin, and a hole transport material. The electron transport material includes a compound having a halogen atom and represented by general formula (1), (2), (3), (4), or (5). The polycarbonate resin has a terminal group having a fluoro group and represented by general formula (10). The hole transport material includes a compound represented by general formula (20), (21), (22), (23), (24), (25), (26), or (27). A charge of calcium carbonate as measured by charging the calcium carbonate through friction with the photosensitive layer is at least +6.5 ?C/g. The photosensitive layer has a Vickers hardness of at least 17.0 HV at 45° C.

Abstract: A photoconductor unit includes a photoconductor and an electrode. The photoconductor includes a base member that is cylindrical and has a hardness that decreases with increasing distance from a first end toward a second end in an axial direction, and a photosensitive layer formed on an outer peripheral surface of the base member. The electrode is in contact with an inner peripheral surface of an open end portion of the base member at the first end.

Abstract: A cylindrical base body of the disclosure includes an outer peripheral surface and an end surface which is connected to the outer peripheral surface. The outer peripheral surface includes a first inclined surface which is inclined inwardly toward the end surface, the end surface includes a second inclined surface which is inclined inwardly toward the outer peripheral surface and is connected to the first inclined surface, and a connecting portion of the first inclined surface and the second inclined surface has a radiused surface.

Abstract: An image forming method includes forming an image with a toner using a photoconductor in which an intermediate layer and a photosensitive layer including a charge generating layer and a charge transport layer are formed overlying an electroconductive substrate, wherein the ionization potential of the surface of the photoconductor and the ionization potential of the surface of the toner satisfy the following relations 1 and 2, |Ip (the surface of the photoconductor)?Ip (the surface of the toner)|?0.18 (eV)?? Relation 1 5.45 (eV)?Ip (the surface of the photoconductor)?5.53 (eV)?? Relation 2 where Ip (the surface of the photoconductor) represents the ionization potential of the surface of the photoconductor and Ip (the surface of the toner) represents the ionization potential of the surface of the toner.

Abstract: An electrophotographic photoreceptor includes a conductive support, a charge generation layer disposed on the conductive support, and a charge transport layer disposed on the charge generation layer. The charge generation layer includes a charge generating material and a vinyl copolymer. The vinyl copolymer includes a structural unit including a chlorine atom, a structural unit including an acyloxy group, and a structural unit including two or more carboxyl groups. The proportion of the structural unit including an acyloxy group to all of the structural units is 13.4 mol % or more and 20.0 mol % or less. The charge transport layer includes a charge transporting material and a binder resin.

Abstract: A photoconductor unit includes a photoconductor and an electrode. The photoconductor includes a base member that is cylindrical and has a hardness that decreases with increasing distance from a first end toward a second end in an axial direction, and a photosensitive layer formed on an outer peripheral surface of the base member. The electrode is in contact with an inner peripheral surface of an open end portion of the base member at the first end.

Abstract: An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer includes a charge generating layer and a charge transport layer. The charge generating layer contains a charge generating material. The charge transport layer contains a hole transport material and a binder resin. The charge transport layer further contains an electron acceptor compound. The hole transport material includes a compound represented by general formula (1). In general formula (1), R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 each represent, independently of one another, a hydrogen atom or a methyl group.

Abstract: Provided is an image forming apparatus capable of estimating lives of components more accurately than before. The image forming apparatus includes an ion conductive component, and a processor for estimating a life of the conductive component. The processor acquires an index value related to energization of the conductive component, and estimates the life of the conductive component based on the index value per unit time.

Abstract: Provided is an electrophotographic roller including a cylindrical base and an elastic layer on an outer peripheral surface of the base, the base having a joint extending from one end to the other end in a longitudinal direction thereof, at least a part of the joint has a gap penetrating the joint in a thickness direction of the base, and a part of a material for the elastic layer entering the gap and covering a portion of an inner peripheral surface of the base near the gap to form an anchor portion of the elastic layer.

Abstract: An electrophotographic photosensitive member includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains a charge generating material, a hole transport material, an electron transport material, and a binder resin. The photosensitive layer has a scratch resistance depth of no greater than 0.50 ?m.

Abstract: There is provided an electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus that are excellent in charging properties and can suppress residual potential in the case where a strontium titanate particle is used as a metal oxide particle in an undercoat layer of the electrophotographic photosensitive member. An electrophotographic photosensitive member in which an undercoat layer contains a strontium titanate particle having a maximum peak at a position of 2?=32.20±0.20 (? represents a Bragg angle) in a CuK? characteristic X-ray diffraction pattern, the maximum peak having a half-value width of 0.10 deg or more and 0.50 deg or less, and a process cartridge and an electrophotographic apparatus each provided with the electrophotographic photosensitive member.

Abstract: An electrophotographic photosensitive drum unit usable in a process cartridge includes a cylinder having a photosensitive layer at an outer periphery thereof and an axis L1. A drum flange is provided at one end of the cylinder, with the drum flange including a recess formed on an inside thereof and a gear portion provided along an outer surface of the drum flange. A detachable member is detachably attached to the drum flange and overlaps parts of the recess as seen along a direction of the axis L1, with the detachable member being provided within the drum flange in the direction of the axis L1.

Abstract: An image forming apparatus in which a developer bearing member is disposed below a cleaning member, which cleans a charging member, so as to overlap with the cleaning member when viewed in a vertical direction and includes a base body and an elastic layer covering the base body and having a width in a longitudinal direction of the developer bearing member that accommodates the entire region of the cleaning member in the longitudinal direction. In the longitudinal direction, the cleaning member is disposed at a position where the entire region thereof in the longitudinal direction is accommodated in the width of the elastic layer.

Abstract: This electrophotographic photosensitive body (20) comprises a supporting body (20a) and a photosensitive layer (20b) that is formed on the surface of the supporting body (20a). The surface of the photosensitive layer (20b) has an arithmetic mean roughness Ra within the range of from 20 nm to 100 nm (inclusive), a ten-point average roughness Rz within the range of from 0.2 ?m to 1.0 ?m (inclusive) and a mean spacing of profile irregularities Sm of 20 ?m or less in the initial stage of use.

Abstract: An electrophotographic photoreceptor includes a conductive substrate and a photosensitive layer of a single-layer type disposed on the conductive substrate. The photosensitive layer has an absorption coefficient of 0.008 or less at a wavelength of 1000 nm and contains a binder resin, a charge generating material, an electron transporting material, and a hole transporting material. The charge generating material is at least one selected from a hydroxygallium phthalocyanine pigment and a chlorogallium phthalocyanine pigment and is contained in an amount of 0.9% by weight or more and 1.8% by weight or less relative to the binder resin.

Abstract: Provided is an electrographic photoconductor resistant to surface discharge and having good wear resistance. The electrographic photoconductor has a conductive support and a photosensitive layer disposed on the conductive support, the photosensitive layer containing a charge generation material and a charge transport material. A layer forming the surface of the electrographic photoconductor contains a resin binder forming the layer and a layered carbide dispersed in the resin binder. The layer forming the surface has a light transmittance in the range of 20 to 98% at a wavelength of 350 to 800 nm.

Abstract: A photoconductor is provided. The photoconductor includes a cylindrical conductive support, a water-repellent resin film, a coating film, and a flange. The cylindrical conductive support has an end part having an inner circumferential surface having a surface roughness Rz of from 3 to 10 ?m. The water-repellent resin film is on the inner circumferential surface of the end part of the cylindrical conductive support. The coating film is on an outer circumferential surface of the cylindrical conductive support. The flange has a cylindrical fitting part having an outer circumferential surface secured to the inner circumferential surface of the end part of the cylindrical conductive support.

Abstract: A conductive support is formed of a bottomless hollow cylindrical member being made of metal and having a thickness t of equal to or less than 0.5 mm, the conductive support including: a chamfer portion on an outer peripheral surface side of at least one end of the conductive support over an entire circumferential direction, wherein the chamfer portion has a chamfer angle a of equal to or greater than 10° and less than 30° with respect to the outer peripheral surface, and a chamfer width b equal to or greater than 0.05 mm in an end surface, and wherein an end surface width c is equal to or greater than 0.1 mm in the end surface including the chamfer portion.

Abstract: The object of the present invention is to provide a toner for development of electrostatic images (hereinafter referred to as toner) which, while preventing dust during fixation, secures improved hot offset resistance and is excellent in providing good image quality. The invention relates to the toner that comprises a binder resin, a colorant and a wax, wherein the wax has, while in a state of being contained in the toner, a melting point of from 55° C. to 90° C., and the value Dt of the toner satisfies a specific formula.

Abstract: In an electrophotographic photosensitive member, a circumferential surface has concave portions that are independent one another; each of the concave portions has an opening, a contour of the opening has an apex having an angle ? of more than 0° and 90° or less on at least an upstream side of a rotational direction of the electrophotographic photosensitive member, and has a largest width in an axial direction of the electrophotographic photosensitive member of 20 ?m or more and 80 ?m or less, a width of the contour in the axial direction of the electrophotographic photosensitive member decreasing from a portion having the largest width toward the apex, when viewing each of the concave portions in the axial direction, each of the concave portions has a depth that decreases from a deepest point of each of the concave portions toward the apex.

Abstract: An endless belt includes a polyimide resin layer in which a content of at least one solvent selected from a solvent group A consisting of a urea solvent, an alkoxy group-containing amide solvent, and an ester group-containing amide solvent is from 50 ppm to 2,000 ppm.

Abstract: Provided is an electrophotographic apparatus, including an electrophotographic photosensitive member, a charging unit arranged in a non-abutment manner with respect to the electrophotographic photosensitive member, a cleaning unit or a developing unit arranged in abutment against the electrophotographic photosensitive member, and a transferring unit.

Abstract: A developing roller includes a conductive axis body; a conductive elastic layer overlying the conductive axis body; and a toner bearing layer overlying the conductive elastic layer and having a surface dispersed with particles having an average particle diameter of from 11 nm to 40 nm. The rotary torque is from 2.5 N to 3.5 N.

Abstract: Organic EL elements are configured so that at least a hole injection layer and a light-emitting layer are laminated between a first electrode and a second electrode, and a bank defines an area in which the light-emitting layer is to be formed. An inner portion of the hole injection layer is depressed to define a recess. An upper peripheral edge of the recess is covered with a part of the bank.

Abstract: A flywheel includes a rotation shaft, a flywheel body, and a protruding body. A first end of the rotation shaft is supported by a rotating body. The flywheel body is provided at a second end of the rotation shaft and rotates together with the rotation shaft. The protruding body protrudes from a surface at a rotating-body side of the flywheel body and extends in a circumferential direction of the rotation shaft.

Abstract: To reduce the influence of a coupling pin that fixes a shaft to a photoreceptor drum on rotation of a photoreceptor drum. To provide photoreceptor device including: a photoreceptor drum having an insertion hole formed along a lengthwise direction; and a flange that is provided at a lengthwise end portion of the photoreceptor drum and has a through hole formed thereon at a position to overlap the insertion hole, wherein the flange has a first protruding portion and a second protruding portion that: are provided on an end surface at which the through hole is provided and around the through hole; and protrude from the end surface, the first protruding portion has a first opening at a position facing the through hole, and the second protruding portion is provided at a position opposite to the first opening across a center of the through hole on the end surface.