Abstract: A charging device includes: a charging roller to charge a surface of the image carrier by rotating in contact with an image carrier; a cleaning roller to clean a surface of the charging roller by rotating in contact with the charging roller; a bearing to hold the charging roller and the cleaning roller so that a distance between an axis of the charging roller and an axis of the cleaning roller is constant; and a biaser to apply a biasing force to the bearing in a direction to bring the charging roller into press contact with the image carrier, wherein the bearing has a first bearing to support the axis of the cleaning roller and a second bearing to support the axis of the charging roller, and the first bearing is disposed inward from the second bearing in a roller axial direction of the cleaning roller and the charging roller.

Abstract: A charging device includes a charging member that is rotatable and contacts and electrically charges a surface of a charging target member; and a cleaning member that is rotatable and cleans a surface of the charging member, wherein the cleaning member includes a core bar extending in a lengthwise direction, a foam member that is helically wound around the core bar while forming a gap in the lengthwise direction and contacts the charging member, and a first adhesive agent that is provided between the foam member and the core bar, the first adhesive agent contacting a part of the foam member and another part of the foam member that are formed to adjoin each other in the lengthwise direction via the gap.

Abstract: A cleaning body includes a core, a foam elastic layer that is disposed to be wound around an outer peripheral surface of the core in a helical shape from one end to the other end of the core, and an adhesive layer that adheres the core and the foam elastic layer, in which a diameter of a tip portion of a cell skeleton protruding on a surface of the foam elastic layer is equal to or less than 50 ?m, and in a case where an inner peripheral length of the foam elastic layer in a cross section of the core in a radial direction is X (mm) and a thickness of the foam elastic layer is Y (mm), a value of X×Y2 is equal to or greater than 45.

Abstract: A cleaning device cleans a discharge wire that discharges electric charge onto a discharge target. The cleaning device moves in a longitudinal direction oldie discharge wire. The cleaning device includes a first contact portion that contacts and cleans the discharge wire and a second contact portion that contacts and cleans the discharge wire. When the first contact portion and the second contact portion clean the discharge wire, the first contact portion and the second contact portion sandwich the discharge wire in a discharge direction in which the discharge wire discharges the electric charge onto the discharge target. The discharge direction is parallel to a radial direction of the discharge wire.

Abstract: A charging device for electrically charging a rotatable image bearing member includes a corona charger including a discharging wire, a rotatable rotation shaft provided along the discharging wire and provided with a helical groove on an outer peripheral surface thereof, a motor configured to rotate the rotation shaft, and a movable member including a projected portion engaging with the helical groove and mounted on the rotation shaft so as to be movable along the rotation shaft with rotation of the rotation shaft. In addition, a cleaning member is provided on the movable member to clean the discharging wire, and a brush member is provided on the movable member and configured to brush the helical groove.

Abstract: A housing includes a first side wall having a first opening and a second side wall arranged spaced away from the first side wall in a first direction. A drawer detachably supports a drum unit. The drawer moves through the first opening between an inside position at which the drawer is located inside the housing and an outside position at which the drawer is located outside the housing. An LED unit moves between: a first position at which the LED unit exposes the photosensitive drum; and a second position at which the LED unit is farther away from the photosensitive drum than at the first position and the LED unit is closer to the first side wall in the first direction than at the first position.

Abstract: A discharger includes a first electrode, a second electrode, a tensioning member, a protrusion, and a pressing member. The first electrode extends in a longitudinal direction. The second electrode is disposed between the first electrode and an image carrier member, and includes a netlike portion including multiple openings through which electric charges discharged from the first electrode pass. The tensioning member supports the second electrode while exerting a tension on the second electrode in the longitudinal direction. The protrusion is disposed on the second electrode on an outer side of the netlike portion in the longitudinal direction. The protrusion protrudes beyond the netlike portion in a thickness direction of the second electrode. The pressing member presses the second electrode in the thickness direction. The pressing member is noncontact with the protrusion.

Abstract: An image carrier unit includes an image carrier, a charging device including a charging member, a cleaning member, a pair of bearing members rotatably supporting the charging member and the cleaning member, a biasing member biasing the bearing members in an approaching direction to the image carrier, and a charging housing holding the charging member and the cleaning member, and a pair of separation members. The bearing members each include a first bearing portion supporting a first rotary shaft of the charging member, a second bearing portion supporting a second rotary shaft of the cleaning member, and an engaged portion. The first bearing portion has an elongated hole shape having a greater inner diameter in an approach/separation direction. The separation members are each inserted between the charging housing and the engaged portion, thus causing the bearing members to move in such a direction as to separate from the image carrier.

Abstract: An image forming apparatus includes: an intermediate transfer belt that carries a toner image first transferred and is rotated to transport the toner image to a second transfer position; a second transfer belt that is rotated to come into contact with the intermediate transfer belt and pass through the second transfer position of the intermediate transfer belt; a plate-like cleaning unit that comes into contact with an outer circumferential surface of the second transfer belt to clean the outer circumferential surface; and a dispersion unit that comes into contact with a portion of the outer circumferential surface of the second transfer belt to disperse toner which passes through the portion on a downstream side of the cleaning unit and on an upstream side of the second transfer position.

Abstract: A cleaning body includes a core and a foamed elastic layer spirally wound around an outer circumferential surface of the core from one end of the core to the other end. An end portion of a cell skeleton protruding from a surface of the foamed elastic layer has an equivalent circle diameter of 50 ?m or less. The foamed elastic layer has a spiral pitch R2 of 5 mm or less and a spiral angle ? of 15° or less.

Abstract: A drum cartridge is mountable in and dismountable from an image forming apparatus without including a developing device. The drum cartridge includes an image bearing member, a charging member, and a cleaning member. The cleaning member includes an elastic layer contacting the charging member. The elastic layer includes a foam member and is made of a material having Asker-C hardness of 5-30 degrees.

Abstract: Provided is a silicone foam sheet that expresses excellent bubble removability, that has satisfactory adhesiveness with an adherend and satisfactory sealability, that maintains the expression of these effects even when its thickness is reduced, that preferably expresses a stable modulus of elasticity over a region from a low-temperature region to a high-temperature region, and that suppresses both of its compression set in the low-temperature region and its compression set in the high-temperature region to low levels. Also provided is a method of producing such silicone foam sheet. The silicone foam sheet comprises an open-cell structure having a thickness of from 10 ?m to 3,000 ?m, wherein an open-cell ratio is 90% or more, an average cell diameter of the silicone foam sheet is from 1 ?m to 50 ?m, and 90% or more of all cells therein each has a cell diameter of 80 ?m or less.

Abstract: An image forming apparatus includes an intermediate transfer member that contacts an image bearing member to form a primary transfer portion, contacts a secondary transfer member to form a secondary transfer portion, and contacts a charging member that can receive a voltage from a charging power source, to form a charging portion. A toner image borne on the image bearing member is primarily transferred to the intermediate transfer member and secondarily transferred to a transfer material. If toner remains on the intermediate transfer member, the charging member electrically charges the remaining toner. If driving of the intermediate transfer member causes toner to drop onto the intermediate transfer member from the charging member, The timing at which to start image formation is controlled to prevent the dropped toner from moving to a transfer material conveyed to the secondary transfer portion.

Abstract: The pixels counting unit divides an area in a main-scanning direction of a recording material on which image formation is performed into a plurality of areas 1 to n based on a width that is a length in the main-scanning direction of the recording material, and measures a pixels count with respect to each area among the plurality of areas 1 to n defined by dividing the area in the main-scanning direction of the recording material.

Abstract: An image forming apparatus includes a photoconductive drum, a charging roller, and a cleaning member. The charging roller is positioned to contact a surface of the photoconductive drum and configured to charge the surface of the photoconductive drum. The cleaning member is configured to contact a surface of the charging roller. The cleaning member includes a shaft extending along a rotational axis and a spiral portion spiraling around the shaft along a length of the shaft parallel to the rotational axis. A width of the spiral portion at a central region of the cleaning member is greater than a width of the spiral portion at an end region of the cleaning member.

Abstract: A charging device includes: a charging member that is rotatable and has a peripheral surface to be in contact with a charging target and to which a voltage is to be applied for charging the charging target; a removing member that includes a core and a removing material spirally wound one to less than two times around the core and rotates and comes into contact with the charging member to remove an unnecessary material from the peripheral surface of the charging member; and a detecting unit that detects a current flowing between the charging member and the removing member.

Abstract: A charging device includes a charging roller and a cleaning roller that includes a core and a foamed elastic layer disposed on an outer circumferential surface of the core and that rotates in contact with a surface of the charging roller. The number of ends of a cell skeleton that protrude from a surface of the foamed elastic layer is 25 ends/mm2 or more and 50 ends/mm2 or less. The cleaning roller is disposed in contact with the charging roller such that the compression ratio of the foamed elastic layer is 30% or less. The compression ratio is represented by Equation (1): compression ratio (%)=(r1/2+r2/2?d)/t1×100??Equation (1): where r1 is the outer diameter (mm) of the cleaning roller, r2 is the outer diameter (mm) of the charging roller, d is the interaxial distance (mm) between the charging roller and the cleaning roller, and t1 is the thickness (mm) of the foamed elastic layer of the cleaning roller.

Abstract: A charging device includes a charging member and a cleaning member. The charging member electrically charges a surface of a charging target member and is rotatable while being in contact with the surface of the charging target member. The cleaning member is in contact with a surface of the charging member and removes a foreign object attached to the surface of the charging member. Surface free energy of the surface of the charging member is 5.00 dynes per centimeter or more. A dynamic friction coefficient of the surface of the charging member and a surface of the cleaning member falls within a range from 0.48 to 0.88 both inclusive. The surface free energy and the dynamic friction coefficient satisfy a relation represented by the following expression (1). E??63?+69??(1) “E” is the surface free energy in dynes per centimeter, and “?” is the dynamic friction coefficient.

Abstract: An image forming apparatus includes a photosensitive member and a charging roller to which a direct current voltage is applied. A difference between a first potential (before charging) and a second potential (after charging) of a surface of the photosensitive member in an image forming operation is smaller than 100 V. The charging roller includes a shaft portion, an elastic layer provided on an outer periphery of the shaft portion, and a surface layer provided on an outer periphery of the elastic layer. A ten point height of roughness profile Rz (?m) and a root mean square slope R?q with respected to a surface of the charging roller satisfy Rz?7 and R?q?0.1.

Abstract: A charging device includes: a charging member that charges an image holding member according to a contact charging method, and includes a conductive substrate and a surface layer provided on the conductive substrate; and a clean member that cleans the charging member while contacting the charging member, and includes a shaft and a foamed elastic layer provided on the shaft, wherein a ratio of a distance between irregularities in an axial direction of the surface layer in the charging member (Sm) to a width of a nodal section of a foam cell wall surface protruding from a surface of the foamed elastic layer in the clean member (W) satisfies 2.4?Sm/W?5.9.

Abstract: A cleaning body includes a shaft and an elastic layer disposed by being spirally wound around an outer circumferential surface of the shaft from one end to the other end of the shaft, wherein a relationship between line roughness of a protruding portion formed at an end portion of the elastic layer in a width direction (RaE) and line roughness of a center portion of the elastic layer in the width direction (RaV) satisfies 5?RaE/RaV.

Abstract: A transmission for a developer unit that includes a developer roller to apply LEP ink to a photoconductor, a cleaner roller to clean the developer roller, and a squeegee roller to squeegee ink on the developer roller. In one example, the transmission includes a mechanical drive train to, with the cleaner roller, simultaneously drive the developer roller at a first surface speed and the squeegee roller at a second surface speed slower than the first surface speed.

Abstract: A cartridge is detachably provided to a main body of an image forming apparatus. The cartridge includes an image bearing member which is rotatable, a charging roller which contacts and charges the image bearing member, and a cleaning member which cleans the charging roller with the brush portion. In a section substantially orthogonal to a rotational axis of the charging roller, a contact point between a surface of the image bearing member and a tangent crossing a downstream end of an abutment region of the brush portion against the charging roller in a rotation direction of the charging roller among tangents to the image bearing member is vertically above a horizontal line passing through a center of the image bearing member, and an upstream end of the abutment region in the rotation direction of the charging roller is vertically above the downstream end in the rotation direction.

Abstract: An image forming apparatus executes charging, exposure, toner-supply suspension, and electric-field generation while a photosensitive member rotates at least a full turn. In the charging, a charger charges a portion of a circumferential surface of the photosensitive member. In the exposure, an exposure device exposes the portion, which has been charged in the charging, of the circumferential surface. In the toner-supply suspension, before the portion, which has been exposed in the exposure, of the circumferential surface passes a position at which developer from a developing unit is configured to initially adhere to the circumferential surface, a developing unit stops supplying developer to the photosensitive member. In the electric-field generation, an electric field is generated in a portion of the photosensitive layer of the photosensitive member corresponding to the portion, which has been exposed by the exposure device, of the circumferential surface.

Abstract: A rubber member for coating a developing roll which is obtained by coating a coating layer component around a developing roll having a rubber substrate layer and curing the coating layer component is described. The coating layer component contains: (A) a liquid binder containing at least a polyol, an isocyanate compound and reactive silicone oil; (B) silicone rubber particles having a hardness according to JIS K6253: 1997 by Durometer A, measured instantaneously, of 20 to 80 degrees, and a rubber particle size of 0.2 to 10 pm; and a diluting solvent. A ratio of a thickness of the coating layer after curing and a particle size of the rubber satisfies: the rubber particle size/a coating layer thickness <0.3.

Abstract: A corona discharge device including a corona electrode provided with multiple sharpened tip portions in a row includes a cleaning member which cleans the tip portions of the corona electrode while reciprocating along a predetermined movement direction set in advance with the tip portions biting into the cleaning member. A cleaning position at a surface of the cleaning member is different in a direction intersecting a longitudinal direction of the corona electrode between when the cleaning member moves toward one side in the movement direction and when the cleaning member moves toward another side in the movement direction.

Abstract: An image forming method includes when an image forming device is in a non-image-forming stage, applying voltages to a surface of a photosensitive element and a surface of a developer element of the image forming device to form an electric field. Applying the voltages includes: forming a first potential difference between the photosensitive element and the developer element in a first stage, and forming a second potential difference between the photosensitive element and the developer element in a second stage. When a developer used by the developer element is a negatively charged developer, a direction of the first potential difference and a direction of the second potential difference are in a direction from the developer element to the photosensitive element. When positively charged, the direction of the first potential difference and the direction of the second potential difference are in a direction from the photosensitive element to the developer element.

Abstract: A cleaning member includes a core and first and second foamed elastic layers wound around an outer peripheral surface of the core in a double-helical pattern. The compressive stress F1 of the first foamed elastic layer is greater than the compressive stress F2 of the second foamed elastic layer. The cleaning member cleans a member to be cleaned with the first and second foamed elastic layers in contact with a surface of the member to be cleaned.

Abstract: It is intended to provide a charging member capable of maintaining high charging performance even when used over a long period. The charging member has an electroconductive support and an electroconductive elastic layer as a surface layer, wherein the electroconductive elastic layer has a roughened surface, and the electroconductive elastic layer has an average Martens' hardness Mc of 2 N/mm2 or larger and 20 N/mm2 or smaller measured with an indentation strength of 0.04 mN at a core surface defined according to a three dimensional surface texture standard (ISO 25178-2:2012), and has an average viscosity Vc of 70×10?3 V or smaller measured in a square of 2 ?m long×2 ?m wide field of view under a scanning probe microscope.

Abstract: To provide a charging device that allows a discharging electrode to be cleaned without damaging a protruding portion at an end portion of the discharging electrode. The device is provided with: a discharging electrode including a plurality of protruding portions arranged along a predetermined direction, the discharging electrode discharging electricity from at least part of the protruding portions; a cleaner for cleaning at least some protruding portions included in the plurality of protruding portions; a cleaner conveyance mechanism for conveying the cleaner along the predetermined direction for performing the cleaning, such that the cleaner interferes with at least some protruding portions included in the plurality of protruding portions; and a cleaner height adjustment mechanism for adjusting a height of the cleaner in a vicinity of the protruding portion where the cleaner reaches at first.

Abstract: An electrophotographic image forming apparatus includes: an electrophotographic photosensitive body including an electroconductive substrate, and a charge generating layer, a charge transfer layer and a surface protective layer laminated on the substrate in this order, and a charging roller for causing contact electrification on the surface of the electrophotographic photosensitive body, wherein at least the surface protective layer contains inorganic microparticles having a fluorine compound on the surfaces and a binder resin, and the surface of the charging roller has a maximum height roughness Rz?0.5 ?m.

Abstract: A cleaning device includes a cleaning member, a first bearing member, a second bearing member, and a moving mechanism. The cleaning member includes a shaft portion and an elastic layer disposed around the shaft portion. The elastic layer is brought into contact with a rotating charging body. The cleaning member cleans the charging body while rotating. The first bearing member supports a first end portion of the shaft portion while rendering the shaft portion rotatable. The second bearing member supports a second end portion of the shaft portion while rendering the shaft portion rotatable. The moving mechanism is supported by the first bearing member and the second bearing member. The moving mechanism periodically moves the shaft portion in an axial direction of the shaft portion together with a rotation of the cleaning member.

Abstract: A cleaning device includes a cleaning roller, a cleaning blade, a toner layer forming member and a regulating member. The cleaning roller comes into contact with a surface of a rotating image carrier and rotates. The cleaning blade comes into contact with the image carrier at a downstream side from the cleaning roller in a rotating direction of the image carrier and scrapes toner adhered to the image carrier. The toner layer forming member receives and collects the toner scraped by the cleaning blade and feeds the toner to the cleaning roller to form a toner layer on the cleaning roller. The regulating member comes into contact with the cleaning roller to regulate thickness of the toner layer. The regulating member is controlled so as to thicken thickness of the toner layer formed on the cleaning roller as rotating rate of the image carrier becomes slower.

Abstract: A charging device includes a first cleaning member that cleans a surface of a charging wire by moving along the wire while being in contact with the wire at a first side; and a second cleaning member that cleans the surface of the wire by moving while being in contact with the wire at a second side, and moving relative to the first cleaning member in a crossing direction that crosses a wire length direction.

Abstract: A cleaning body includes a shaft and an elastic layer that is helically wound around the shaft from one end side to the other end side of the shaft and fixed on the shaft and that cleans a body to be cleaned while the elastic layer rotates. The elastic layer includes a division portion having plural divided segments and having a length of from 20% to 70% of the full length of the elastic layer. The division portion is located in a longitudinal central portion of the elastic layer. In the sectional view perpendicular to the axial direction of the shaft, a minimum thickness part in the longitudinal central portion of the elastic layer is from 5% to 12% thicker than a minimum thickness part in each longitudinal end portion of the elastic layer.

Abstract: A corona discharge device including a corona electrode provided with multiple sharpened tip portions in a row includes a cleaning member which cleans the tip portions of the corona electrode while reciprocating along a predetermined movement direction set in advance with the tip portions biting into the cleaning member. A cleaning position at a surface of the cleaning member is different in a direction intersecting a longitudinal direction of the corona electrode between when the cleaning member moves toward one side in the movement direction and when the cleaning member moves toward another side in the movement direction.

Abstract: An image forming apparatus according to an embodiment includes a photoconductive drum and a charging roller facing the photoconductive drum. The charging roller receives a potential bias. A controller performs an electrostatic cleaning operation by alternately applying, to the charging roller, a first bias and a second bias of opposite polarity to the first bias so that contaminants repelled by the first bias and contaminants repelled by the second bias are transferred from the charging roller to the photoconductive drum.

Abstract: A cleaning roller includes a shaft and an elastic body. The shaft extends in an axial direction where a center axis of the shaft extends. The shaft defines a radial direction and has a circumferential surface. The elastic body is helically wound about the shaft and defines a helical direction. The elastic body has a widthwise dimension in a widthwise direction orthogonal to the helical direction and to the radial direction. The elastic body has a base end portion extending in the helical direction and a distal end portion extending in the helical direction. The base end portion is in contact with the circumferential surface and fixed thereto. The distal end portion has a sharp edge and is positioned farthest from the circumferential surface in the radial direction. The widthwise dimension is gradually reduced from the base end portion to the distal end portion in the radial direction.

Abstract: A cleaning roller including a shaft including a rotational axis extending in an axial direction and an elastic layer covering the shaft. The elastic layer includes a base covering the shaft and a first helical protrusion protruding from the base and having a first helical ridge.

Abstract: Image carrying member units are each provided with an image carrying member, a charging device, and a pair of support frames. The charging device has: a charging roller that charges the image carrying member by rotation driven by the image carrying member; a cleaning member for cleaning the charging roller; a pair of bearing members for rotatably supporting both end parts of the cleaning member and the charging roller; and biasing members for biasing the bearing members in a direction in which the same moves closer to the image carrying member. An image carrying member bearing part and a first cleaning member bearing part for rotatably supporting one end part of the rotating shaft for the cleaning member where an input side gear is provided, are formed integrally on a first support frame for supporting one end part of the image carrying member where an output side gear is provided.

Abstract: An image forming apparatus includes a cleaning device located, in a direction in which an intermediate transfer belt rotates, downstream of a second transfer position and upstream of a first transfer position, at which a first transfer device transfers a toner image onto the intermediate transfer belt, the cleaning device cleaning the intermediate transfer belt; and a charging member located upstream of the first transfer position and downstream of the cleaning device in the direction in which the intermediate transfer belt rotates, the charging member having a shape of a roller having a diameter smaller than a diameter of a driving roller that drives the intermediate transfer belt to rotate the intermediate transfer belt, the charging member charging the intermediate transfer belt by holding the intermediate transfer belt between the charging member and the driving roller and touching an outer surface of the intermediate transfer belt.

Abstract: A charging device includes an electrode, a cleaning member that moves along the electrode and cleans the electrode, a rotating member that is disposed along the electrode, includes a spiral protruding portion on an outer circumferential surface thereof, and circumferentially rotates, and a movable member to which the cleaning member is attached. The movable member includes a first through hole through which the rotating member passes, a first pressed portion that is provided on an inner circumferential surface of the first through hole and pressed by the protruding portion of the rotating member, and a second pressed portion that is disposed at a different position from a position of the first pressed portion in an axial direction of the rotating member and that is disposed such that one or more turns of the protruding portion are positioned between the second pressed portion and the first pressed portion.

Abstract: A cleaning member includes a core and an elastic layer helically wound around an outer peripheral surface of the core so as to extend from one end to the other end of the core. When the cleaning member is rotated by a member to be cleaned, a non-contact region in which a first end portion and a second end portion of the elastic layer in an axial direction of the core are not in contact with the member to be cleaned is in a range from approximately 0° to approximately 60° in terms of a rotation angle of the cleaning member viewed from one side in the axial direction of the core.

Abstract: A charging device includes a first cleaning member, a first electrode, a second cleaning member, a second electrode, and a movable body. The first cleaning member moves in one direction. The first electrode is cleaned by the first cleaning member moving in the one direction. The second cleaning member moves in the one direction together with the first cleaning member and moves so that a downstream end portion thereof, which is located downstream in the one direction, serves as a leading portion and an upstream end portion thereof comes after the downstream end portion. The second electrode includes a first region and a second region. The first region is cleaned by the second cleaning member moving in the one direction. The second region is located downstream in comparison with the first region in the one direction.

Abstract: A charging device includes: an electrode; a cleaning member that cleans the electrode; a moving body that moves along the electrode, the cleaning member that is attached to the moving body; and a rotation member that is disposed along the electrode and that includes a spiral protrusion on an outer circumferential surface thereof to move the moving body, the rotation member that is rotated in a circumferential direction. A plurality of kinds of pitch intervals of the protrusion are provided on at least a central portion of the rotation member in a longitudinal direction.

Abstract: A cleaning member includes a core and an elastic layer disposed on an outer peripheral surface of the core. A circumferential cover length over which the elastic layer covers the core in a circumferential direction is greater at least at one of first and second end portions in an axial direction of the core than at a central portion in the axial direction. The central portion in the axial direction extends from one end to the other end of the core in the axial direction. When the cleaning member is rotated by a member to be cleaned, a non-contact region in which the first and second end portions in the axial direction are not in contact with the member to be cleaned is in a range from approximately 0° to approximately 15° in terms of a rotation angle of the cleaning member viewed from one side in the axial direction.

Abstract: An image forming apparatus includes an image bearer to bear a latent electrostatic image thereon, a developing device to supply a development agent to the latent electrostatic image to obtain a visible image, a transfer roller to contact the image bearer to transfer the visible image to a recording medium, a replenishing device to replenish the developing device with the development agent when a density value read from a density detection pattern formed on the image bearer by the developing device is equal to or less than a threshold, a processing device to conduct a predetermined processing to reduce attachment of the development agent to the transfer roller, and a control device to control the number of times the predetermined processing is performed or processing time in performing the predetermined processing for the processing device, based on whether there is replenishment of the development agent to the developing device.

Abstract: A cleaning device includes a cleaning member, which includes a shaft portion and an elastic layer. The shaft portion is disposed so as to extend in a rotation axis direction of a rotating object that is to be cleaned. The elastic layer is helically disposed on an outer circumferential surface of the shaft portion from one end portion to the other end portion in an axial direction. The elastic layer touches an outer circumferential surface of the object and at least one end surface of the object in the rotation axis direction. A relationship between a cross-sectional area Sa of the object taken perpendicular to an axis of the object and a cumulative total contact area Sb of a portion of the end surface of the object in the rotation axis direction touched by the elastic layer during one rotation of the object satisfies 0.11?Sb/Sa<0.30.

Abstract: A charging unit includes: a charging member that contacts with an image holding body holding an image and charges a surface of the image holding body; a support member that supports the charging member; and a pressing member that has plural springs that expand and contract in a direction from the support member to the image holding body, and pushes the support member toward the image holding body, and at least two of the plural springs of the pressing member are formed by a single metal wire.

Abstract: An image forming apparatus includes an image carrier that carries a developer image formed by a developer including external additives, a charging member for charging the image carrier, a developer carrier that carries the developer, a developer supply member to which a supply voltage is applied for supplying the developer to the developer carrier, a main controller that controls an image formation mode for developing the developer image and controls a cleaning sequence mode for cleaning the charging member, and a voltage controller that changes outputs of the charging voltage, the development voltage and the supply voltage, and executes the cleaning sequence mode based on instructions of the main controller. When executing the cleaning sequence mode, the voltage controller makes an absolute value of the charging voltage larger than that in the image forming mode, and afterwards sets the output of the charging voltage to an OFF state.