Abstract: A drum unit includes: a frame; a first photosensitive drum; a second photosensitive drum; a charger; and a storage medium. The frame includes: a first frame plate; a second frame plate spaced apart from the first frame plate in a first direction; a third frame plate connecting one end of the first frame plate to one end of the second frame plate; and a fourth frame plate connecting another end of the first frame plate to another end of the second frame plate. The first photosensitive drum and the second photosensitive drum are rotatably supported by the frame. The second photosensitive drum is spaced apart from the first photosensitive drum and positioned closer to the third frame plate than the first photosensitive drum to the third frame plate in a second direction. The storage medium has an electrical contact surface positioned at an outer surface of the third frame plate.

Abstract: A fixing device incorporated in a main body of an image forming apparatus includes a heater, a rotatable body, and a pressure roller. The rotatable body is configured to be heated by the heater. The pressure roller is configured to form a nip region in cooperation with the rotatable body to nip a sheet at the nip region between the pressure roller and the rotatable body. The pressure roller includes a shaft, and an elastic layer covering a peripheral surface of the shaft. The elastic layer has a thickness of at least 1 millimeter to at most 3 millimeters. The pressure roller has a peripheral surface whose hardness is in a range of at least 60 to at most 67 on the Asker C scale.

Abstract: A drum unit includes: a frame; a first photosensitive drum; a second photosensitive drum; a charger; and a storage medium. The frame includes: a first frame plate; a second frame plate spaced apart from the first frame plate in a first direction; a third frame plate connecting one end of the first frame plate to one end of the second frame plate; and a fourth frame plate connecting another end of the first frame plate to another end of the second frame plate. The first photosensitive drum and the second photosensitive drum are rotatably supported by the frame. The second photosensitive drum is spaced apart from the first photosensitive drum and positioned closer to the third frame plate than the first photosensitive drum to the third frame plate in a second direction. The storage medium has an electrical contact surface positioned at an outer surface of the third frame plate.

Abstract: A fixing device includes a heater, an endless belt, a holder, a temperature detector, and a partition sheet. The heater includes a substrate, and a resistance heating element provided on the substrate, and has a frontside surface and a backside surface opposite to the frontside surface. The endless belt is configured to rotate around the heater and has an inner peripheral surface in contact with the frontside surface of the heater. The holder holds the heater. The temperature detector is configured to detect a temperature of the heater and has a detection surface that detects a temperature. The partition sheet is located between the backside surface of the heater and the holder, and is in contact with the detection surface. A length of the partition sheet in a direction of conveyance of a recording material is longer than a length of the heater in the direction of conveyance.

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: 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: A fixing unit includes a heater including a substrate and a resistance heating element disposed on the substrate, an endless belt configured to move about the heater and having an inner peripheral surface in contact with the heater, and a holder holding the heater in a hole of the holder, a metal sheet in contact with the substrate and a temperature sensor configured to detect a temperature of the heater. The temperature sensor is in contact with the metal sheet through the hole, and an end portion of the metal sheet in a lateral direction of the substrate is inserted into the hole so that the metal sheet is positioned with respect to the heater in the lateral direction.

Abstract: A heating unit includes a heater, a temperature sensor, an endless belt, a holder, a first heat conductive member, and a second heat conductive member. The first heat conductive member includes a first heater-side surface facing the heater, a first opposite surface, and an opening. The first heat conductive member has a heat conductivity higher than that of the substrate. The second heat conductive member includes a second heater-side surface facing the heater and a second opposite surface. The second heat conductive member is positioned at a position corresponding to the opening when viewed in an orthogonal direction orthogonal to the first opposite surface. The temperature sensor is in contact with the second opposite surface of the second heat conductive member.

Abstract: An image forming apparatus includes a sheet-supplier, a photoconductor, a fuser and a controller. The controller is configured to, in a case where the number of sheets to be printed indicated by a printing job is less than a first predetermined number of sheets, start supplying a sheet by a sheet-supplier at a timing when a second period of time has been passed from a timing when the temperature in the fuser has reached a second temperature, and, in a case where the number of sheets to be printed is equal to or greater than the first predetermined number of sheets, start supplying the sheet by the sheet-supplier at a timing when the second period of time has been passed from a timing when the temperature in the fuser has reached a first temperature larger than the second temperature.

Abstract: A fixing device includes a heater, an endless belt, a holder, a temperature detector, and a partition sheet. The heater includes a substrate, and a resistance heating element provided on the substrate, and has a frontside surface and a backside surface opposite to the frontside surface. The endless belt is configured to rotate around the heater and has an inner peripheral surface in contact with the frontside surface of the heater. The holder holds the heater. The temperature detector is configured to detect a temperature of the heater and has a detection surface that detects a temperature. The partition sheet is located between the backside surface of the heater and the holder, and is in contact with the detection surface. A length of the partition sheet in a direction of conveyance of a recording material is longer than a length of the heater in the direction of conveyance.

Abstract: A heating unit includes a heater, a temperature sensor, an endless belt, a holder, a first heat conductive member, and a second heat conductive member. The first heat conductive member includes a first heater-side surface facing the heater, a first opposite surface, and an opening. The first heat conductive member has a heat conductivity higher than that of the substrate. The second heat conductive member includes a second heater-side surface facing the heater and a second opposite surface. The second heat conductive member is positioned at a position corresponding to the opening when viewed in an orthogonal direction orthogonal to the first opposite surface. The temperature sensor is in contact with the second opposite surface of the second heat conductive member.

Abstract: A drum unit includes: a frame; a first photosensitive drum; a second photosensitive drum; a charger; and a storage medium. The frame includes: a first frame plate; a second frame plate spaced apart from the first frame plate in a first direction; a third frame plate connecting one end of the first frame plate to one end of the second frame plate; and a fourth frame plate connecting another end of the first frame plate to another end of the second frame plate. The first photosensitive drum and the second photosensitive drum are rotatably supported by the frame. The second photosensitive drum is spaced apart from the first photosensitive drum and positioned closer to the third frame plate than the first photosensitive drum to the third frame plate in a second direction. The storage medium has an electrical contact surface positioned at an outer surface of the third frame plate.

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: A drum unit includes: a frame; a first photosensitive drum; a second photosensitive drum; a charger; and a storage medium. The frame includes: a first frame plate; a second frame plate spaced apart from the first frame plate in a first direction; a third frame plate connecting one end of the first frame plate to one end of the second frame plate; and a fourth frame plate connecting another end of the first frame plate to another end of the second frame plate. The first photosensitive drum and the second photosensitive drum are rotatably supported by the frame. The second photosensitive drum is spaced apart from the first photosensitive drum and positioned closer to the third frame plate than the first photosensitive drum to the third frame plate in a second direction. The storage medium has an electrical contact surface positioned at an outer surface of the third frame plate.

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: An electronic module includes a circuit board having a mounting surface; a heat generating component mounted on the mounting surface; a frame supporting the circuit board; a cover covering the heat generating component and the mounting surface; and a heatsink mounted on the mounting surface. The heatsink includes at least one wall including a particular wall to which the heat generating component is attached. The heatsink further includes a shade portion provided at the at least one wall. The shade portion is located between the cover and the heat generating component in a direction perpendicular to the mounting surface.

Abstract: A fixing device includes: a heater including a substrate, and a heating pattern; an endless belt configured to rotate around the heater; and a pressure roller. The endless belt is nipped between the pressure roller and the heater. The endless belt is nipped by the substrate and the pressure roller to form a nip portion including a first portion and a second portion. The length of the first portion in a moving direction of the endless belt at the nip portion is less than that of the second portion in the moving direction. The substrate includes: a third portion located corresponding to the first portion in a longitudinal direction of the substrate; and a fourth portion located corresponding to the second portion in the longitudinal direction. The length of the third portion in the moving direction is less than that of the fourth portion in the moving direction.

Abstract: A drum unit includes: a frame; a first photosensitive drum; a second photosensitive drum; a charger; and a storage medium. The frame includes: a first frame plate; a second frame plate spaced apart from the first frame plate in a first direction; a third frame plate connecting one end of the first frame plate to one end of the second frame plate; and a fourth frame plate connecting another end of the first frame plate to another end of the second frame plate. The first photosensitive drum and the second photosensitive drum are rotatably supported by the frame. The second photosensitive drum is spaced apart from the first photosensitive drum and positioned closer to the third frame plate than the first photosensitive drum to the third frame plate in a second direction. The storage medium has an electrical contact surface positioned at an outer surface of the third frame plate.

Abstract: A fixing device includes: a heater including a substrate, and a heating pattern; an endless belt configured to rotate around the heater; and a pressure roller. The endless belt is nipped between the pressure roller and the heater. The endless belt is nipped by the substrate and the pressure roller to form a nip portion including a first portion and a second portion. The length of the first portion in a moving direction of the endless belt at the nip portion is less than that of the second portion in the moving direction. The substrate includes: a third portion located corresponding to the first portion in a longitudinal direction of the substrate; and a fourth portion located corresponding to the second portion in the longitudinal direction. The length of the third portion in the moving direction is less than that of the fourth portion in the moving direction.

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.