Abstract: A fixing device includes a nip formation pad pressing against a pressure rotator via a fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator. The nip formation pad includes a base and a first thermal conductor sandwiched between the base and the fixing rotator at the fixing nip and having a first thermal conductivity greater than a basic thermal conductivity of the base. A first heater and a second heater are disposed opposite an inner circumferential surface of the fixing rotator to heat the fixing rotator. A rotatable light shield moves to a shield position where the light shield is interposed between the second heater and the fixing rotator to shield the fixing rotator from the second heater. The second heater is disposed at a location where the light shield screens the second heater more readily than the first heater.

Abstract: An image forming apparatus includes a fixing rotator and an opposed rotator pressed against the fixing rotator to form a fixing nip therebetween, through which a recording medium bearing a toner image is conveyed. A heater heats the fixing rotator. A temperature sensor contacts the opposed rotator to detect a temperature of the opposed rotator. A conveyor conveys the recording medium to the fixing nip. A driver drives the conveyor. A controller, operatively connected to the temperature sensor and the driver, controls the driver to drive the conveyor to convey the recording medium to the fixing nip based on the temperature of the opposed rotator detected by the temperature sensor. The controller causes the driver to be ready to drive the conveyor when a change in the detected temperature of the opposed rotator per unit time reaches a predetermined threshold.

Abstract: A fixing device includes a fixing rotator and an opposed rotator disposed opposite the fixing rotator to form a fixing nip therebetween through which a recording medium bearing a toner image is conveyed. A heater disposed opposite the fixing rotator heats the fixing rotator. A nip formation pad disposed opposite an inner circumferential surface of the fixing rotator includes a decreased thermal conduction portion having a decreased thermal conductivity to conduct heat in a thickness direction of the nip formation pad perpendicular to an axial direction of the fixing rotator and an increased thermal conduction portion having an increased thermal conductivity to conduct heat in the thickness direction of the nip formation pad. The increased thermal conduction portion is disposed opposite an overheating span of the fixing rotator in the axial direction thereof where the fixing rotator is susceptible to overheating.

Abstract: A fixing device includes: a rotatable fixing member formed as an endless belt; a heat source to heat the fixing member; a nip-forming member being not rotatable and arranged inside the fixing member; and a pressure member arranged outside the fixing member and forming a nip between the pressure member and the fixing member. The nip-forming member is formed of a first heat transmission unit and a sliding sheet. The first heat transmission unit includes an abutting part abutting the fixing member with the sliding sheet therebetween, and a bent part or bent parts extending inside the fixing member at upstream or upstream and downstream of the nip in a transport direction of a recording medium. A retaining part to catch and retain the sliding sheet is provided at a tip of at least the bent part at upstream of the nip in the transport direction.

Abstract: A fixing device includes a fixing rotator rotatable in a predetermined direction of rotation and an opposed rotator disposed opposite the fixing rotator to form a fixing nip therebetween through which a recording medium bearing a toner image is conveyed. A heater is disposed opposite the fixing rotator to heat the fixing rotator. A nip formation pad is disposed opposite an inner circumferential surface of the fixing rotator. The nip formation pad includes a base, a first thermal conductor sandwiched between the base and the fixing rotator and having a first thermal conductivity greater than a thermal conductivity of the base, and a bulge projecting from the first thermal conductor toward the opposed rotator at a downstream end of the first thermal conductor in a recording medium conveyance direction.

Abstract: An image forming apparatus includes a storage to store recording media, a smoothness detector to detect smoothness of the recording media, a memory unit to store smoothness values detected by the smoothness detector, a transfer device to transfer a toner image onto the recording media, a fixing device to fix the toner image onto the recording media, a temperature controller to determine a target fixing temperature for a second and subsequent recording media based on a predicted value calculated from the smoothness values, and a processor to reset the smoothness values in response to detection of an external factor that causes the smoothness detector to provide a smoothness value out of a predetermined range of the predicted value during an image forming operation from when the processor receives a sheet-feeding permission signal of one of the recording media stored in the storage until the recording medium is ejected.

Abstract: A fixing device includes: a rotatable fixing member formed as an endless belt; a heat source to heat the fixing member; a nip-forming member being not rotatable and arranged inside the fixing member; and a pressure member arranged outside the fixing member and forming a nip between the pressure member and the fixing member. The nip-forming member is formed of a first heat transmission unit and a sliding sheet. The first heat transmission unit includes an abutting part abutting the fixing member with the sliding sheet therebetween, and a bent part or bent parts extending inside the fixing member at upstream or upstream and downstream of the nip in a transport direction of a recording medium. A retaining part to catch and retain the sliding sheet is provided at a tip of at least the bent part at upstream of the nip in the transport direction.

Abstract: A recording media smoothness detector includes a sensor and a calculator. The sensor includes a light source to emit light toward a recording medium and a light-detecting device to detect an amount of light reflected by the recording medium. The calculator includes a first memory to store an initial output value of the sensor and a second memory to store a decreased output percentage of the sensor relative to the initial output value per number of recording media detected. The calculator is configured to calculate a decreased output amount of the sensor from the decreased output percentage of the sensor per number of recording media detected, according to number of recording media detected by the sensor, to adjust a luminosity of the sensor based on the calculated decreased output amount of the sensor and determine smoothness of the recording medium based on an output of the sensor after the adjustment.

Abstract: A fixing device includes: a fixing member that is rotatable and in an endless shape; a heat source that heats the fixing member; a nip forming member that is arranged inside the fixing member; and a pressurizing member that is pressurized to be in contact with the nip forming member through the fixing member, to form a fixing nip. The fixing device fixes an unfixed image on a recording medium by passing the recording medium that carries the unfixed image through the fixing nip. The nip forming member includes a base layer, and a high thermal-conductive layer that is arranged on a surface layer of the base layer on a fixing nip side, and that has higher thermal conductivity than the base layer, and in the high thermal-conductive layer, a low thermal-conductive portion is arranged near an end portion in an axial direction of the fixing member.

Abstract: An image forming apparatus includes a storage to store recording media, a smoothness detector to detect smoothness of the recording media, a memory unit to store smoothness values detected by the smoothness detector, a transfer device to transfer a toner image onto the recording media, a fixing device to fix the toner image onto the recording media, a temperature controller to determine a target fixing temperature for a second and subsequent recording media based on a predicted value calculated from the smoothness values, and a processor to reset the smoothness values in response to detection of an external factor that causes the smoothness detector to provide a smoothness value out of a predetermined range of the predicted value during an image forming operation from when the processor receives a sheet-feeding permission signal of one of the recording media stored in the storage until the recording medium is ejected.

Abstract: A fixing device includes a fixing rotator, a nip formation pad disposed opposite an inner circumferential surface of the fixing rotator, and a pressure rotator pressed against the nip formation pad via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator, through which a recording medium is conveyed. A support is disposed opposite the pressure rotator via the nip formation pad to support the nip formation pad against pressure from the pressure rotator. The nip formation pad conducts heat in a thickness direction thereof perpendicular to an axial direction of the fixing rotator and a recording medium conveyance direction. The nip formation pad includes a multi-conductivity layer having a thermal conductivity varying in the axial direction of the fixing rotator and a support side layer contacting the support and having a thermal conductivity greater than a thermal conductivity of the support.

Abstract: A fixing device includes a fixing rotator and a pressure rotator pressed against a nip formation pad via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator, through which a recording medium is conveyed. The nip formation pad includes an increased thermal conduction portion having an increased thermal conductivity and a decreased thermal conduction portion having a decreased thermal conductivity and being inboard from the increased thermal conduction portion in the axial direction of the fixing rotator. The increased thermal conduction portion is disposed opposite a non-conveyance span of the fixing rotator where the recording medium is not conveyed and includes an inboard edge inboard from a lateral edge of the recording medium toward a center of the recording medium in the axial direction of the fixing rotator by a predetermined first distance.

Abstract: A fixing device includes a fixing rotator rotatable in a predetermined direction of rotation and an opposed rotator disposed opposite the fixing rotator to form a fixing nip therebetween through which a recording medium bearing a toner image is conveyed. A heater is disposed opposite the fixing rotator to heat the fixing rotator. A nip formation pad is disposed opposite an inner circumferential surface of the fixing rotator. The nip formation pad includes a base, a first thermal conductor sandwiched between the base and the fixing rotator and having a first thermal conductivity greater than a thermal conductivity of the base, and a bulge projecting from the first thermal conductor toward the opposed rotator at a downstream end of the first thermal conductor in a recording medium conveyance direction.

Abstract: A fixing device includes a fixing rotator and an opposed rotator disposed opposite the fixing rotator to form a fixing nip therebetween through which a recording medium bearing a toner image is conveyed. A heater disposed opposite the fixing rotator heats the fixing rotator. A nip formation pad disposed opposite an inner circumferential surface of the fixing rotator includes a decreased thermal conduction portion having a decreased thermal conductivity to conduct heat in a thickness direction of the nip formation pad perpendicular to an axial direction of the fixing rotator and an increased thermal conduction portion having an increased thermal conductivity to conduct heat in the thickness direction of the nip formation pad. The increased thermal conduction portion is disposed opposite an overheating span of the fixing rotator in the axial direction thereof where the fixing rotator is susceptible to overheating.