Abstract: The fixing device includes a fixing member, a heat source, a pressure member, a nip forming member, and a heat equalizing member. The heat equalizing member covers a face of the nip forming member, the face facing the fixing member, and transfers heat in an axial direction of the fixing member. The fixing member includes at least a tubular base made of metal and a sliding layer made of heat resistant resin on an inner circumferential surface of the base. The heat equalizing member made of aluminum or an aluminum alloy includes an alumite layer on a surface facing an inner circumferential surface of the fixing member. A plurality of micropores in the alumite layer is filled with a solid lubricant having a coefficient of friction lower than that of the alumite layer. The alumite layer has a thickness smaller than that of the sliding layer of the fixing member.

Abstract: A nip formation pad includes a base, a high thermal conduction member, and an attachment. The high thermal conduction member has a thermal conductivity greater than a thermal conductivity of the base. The attachment is attached to the high thermal conduction member by elastic deformation of the attachment on the base held between the high thermal conduction member and the attachment.

Abstract: The fixing device includes a fixing member, a heat source, a pressure member, a nip forming member, and a heat equalizing member. The heat equalizing member covers a face of the nip forming member, the face facing the fixing member, and transfers heat in an axial direction of the fixing member. The fixing member includes at least a tubular base made of metal and a sliding layer made of heat resistant resin on an inner circumferential surface of the base. The heat equalizing member made of aluminum or an aluminum alloy includes an alumite layer on a surface facing an inner circumferential surface of the fixing member. A plurality of micropores in the alumite layer is filled with a solid lubricant having a coefficient of friction lower than that of the alumite layer. The alumite layer has a thickness smaller than that of the sliding layer of the fixing member.

Abstract: A nip formation pad includes a base, a high thermal conduction member, and an attachment. The high thermal conduction member has a thermal conductivity greater than a thermal conductivity of the base. The attachment is attached to the high thermal conduction member by elastic deformation of the attachment on the base held between the high thermal conduction member and the attachment.

Abstract: A heating device includes a tubular rotator that rotates and a heat source that heats the tubular rotator. A thermal conductor includes a first face that contacts the tubular rotator and a second face that is opposite the first face. A first thickness portion is disposed in a first span of the thermal conductor in a longitudinal direction of the thermal conductor. The first thickness portion has a first thickness. A second thickness portion is disposed in at least a part of a second span of the thermal conductor in the longitudinal direction of the thermal conductor. The second span is different from the first span. The second thickness portion has a second thickness that is greater than the first thickness of the first thickness portion. The second thickness portion includes a folded portion that is disposed on the second face.

Abstract: A heating device includes a tubular rotator that rotates and a heat source that heats the tubular rotator. A thermal conductor includes a first face that contacts the tubular rotator and a second face that is opposite the first face. A first thickness portion is disposed in a first span of the thermal conductor in a longitudinal direction of the thermal conductor. The first thickness portion has a first thickness. A second thickness portion is disposed in at least a part of a second span of the thermal conductor in the longitudinal direction of the thermal conductor. The second span is different from the first span. The second thickness portion has a second thickness that is greater than the first thickness of the first thickness portion. The second thickness portion includes a folded portion that is disposed on the second face.

Abstract: A fixing device includes an endless belt that rotates and is heated by a heat source. A thermal conduction aid includes a contact portion, an upstream bent portion, and a downstream bent portion. The contact portion contacts the endless belt. The upstream bent portion and the downstream bent portion are disposed upstream and downstream from the contact portion in a rotation direction of the endless belt, respectively, and are extended in a longitudinal direction of the thermal conduction aid. A recess is disposed in at least one of the upstream bent portion and the downstream bent portion. The recess spans a center of the thermal conduction aid in the longitudinal direction thereof and is recessed from an edge of the at least one of the upstream bent portion and the downstream bent portion in a short direction thereof.

Abstract: A nip forming member includes a base material and a thermal conductive member that overlaps the base material and has a higher thermal conductivity than a thermal conductivity of the base material. The base material has protrusions projecting to one side or another side in a short direction on a part of a longitudinal direction on both sides in the short direction. The thermal conductive member has fitting holes into which the protrusions are fitted in both sides in the short direction.

Abstract: A fixing device includes an endless belt that rotates and is heated by a heat source. A thermal conduction aid includes a contact portion, an upstream bent portion, and a downstream bent portion. The contact portion contacts the endless belt. The upstream bent portion and the downstream bent portion are disposed upstream and downstream from the contact portion in a rotation direction of the endless belt, respectively, and are extended in a longitudinal direction of the thermal conduction aid. A recess is disposed in at least one of the upstream bent portion and the downstream bent portion. The recess spans a center of the thermal conduction aid in the longitudinal direction thereof and is recessed from an edge of the at least one of the upstream bent portion and the downstream bent portion in a short direction thereof.

Abstract: A heating device includes a first rotator, a heater, a second rotator to contact an outer surface of the first rotator, a nip formation pad inside a loop of the first rotator to form a nip, a thermal equalizer to cover a surface of the nip formation pad opposite the first rotator and transport heat in an axial direction of the first rotator, and a lubricant disposed between the thermal equalizer and the first rotator. The thermal equalizer has a plurality of concave portions on a surface opposite the inner surface of the first rotator. The concave portion has a shape substantially symmetrical with respect to a first center line extending in a longitudinal direction of the thermal equalizer and a second center line in a cross section of the concave portion viewed from a direction perpendicular to a direction of movement of the first rotator.

Abstract: A fixing device includes a fixing rotator that rotates and includes an inner face. A pressure rotator is disposed opposite the fixing rotator and rotates. A nip former sandwiches the fixing rotator together with the pressure rotator to form a nip between the fixing rotator and the pressure rotator. The nip former includes an outer face disposed opposite the inner face of the fixing rotator. The inner face of the fixing rotator and the outer face of the nip former sandwich a lubricant. At least one of the inner face of the fixing rotator and the outer face of the nip former includes a projection having a volume smaller than 0.3 ml/m2 and a recess having a spatial volume greater than 0.08 ml/m2. The volume and the spatial volume are three-dimensional surface roughness parameters, respectively, defined by the International Organization for Standardization 25178 standard in an initial state before the fixing rotator rotates.

Abstract: A fixing device includes a fixing rotator that rotates and includes an inner face. A pressure rotator is disposed opposite the fixing rotator and rotates. A nip former sandwiches the fixing rotator together with the pressure rotator to form a nip between the fixing rotator and the pressure rotator. The nip former includes an outer face disposed opposite the inner face of the fixing rotator. The inner face of the fixing rotator and the outer face of the nip former sandwich a lubricant. At least one of the inner face of the fixing rotator and the outer face of the nip former includes a projection having a volume smaller than 0.3 ml/m2 and a recess having a spatial volume greater than 0.08 ml/m2. The volume and the spatial volume are three-dimensional surface roughness parameters, respectively, defined by the International Organization for Standardization 25178 standard in an initial state before the fixing rotator rotates.

Abstract: A fixing device includes a fixing rotator, a pressure rotator, a heat source, a nip formation pad, and a support. The nip formation pad presses against the pressure rotator to form a fixing nip between the fixing rotator and the pressure rotator. The support supports the nip formation pad toward the fixing nip. A longitudinal end portion of the pressure rotator has an outer diameter greater than that of a longitudinal center portion of the pressure rotator. The pressure rotator includes a grip that contacts the nip formation pad via the fixing rotator outside a recording medium with a maximum width conveyable passing through the fixing nip and applies a frictional force to the fixing rotator. The nip formation pad includes a nip face having an inflection point from which a longitudinal direction of the nip face is curved toward the support within an area opposite the grip.

Abstract: A fixing device includes a fixing rotator, a pressure rotator, a heat source, a nip formation pad, and a support. The nip formation pad presses against the pressure rotator to form a fixing nip between the fixing rotator and the pressure rotator. The support supports the nip formation pad toward the fixing nip. A longitudinal end portion of the pressure rotator has an outer diameter greater than that of a longitudinal center portion of the pressure rotator. The pressure rotator includes a grip that contacts the nip formation pad via the fixing rotator outside a recording medium with a maximum width conveyable passing through the fixing nip and applies a frictional force to the fixing rotator. The nip formation pad includes a nip face having an inflection point from which a longitudinal direction of the nip face is curved toward the support within an area opposite the grip.

Abstract: A fixing device includes a fixing rotator and a pressure rotator that is disposed opposite the fixing rotator. A nip former is disposed inside a loop formed by the fixing rotator and disposed opposite the pressure rotator via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator. The fixing rotator slides over the nip former. A flange supports the fixing rotator at both lateral ends of the fixing rotator in a longitudinal direction of the fixing rotator. The nip former includes a base and a thermal conductor that has a thermal conductivity greater than a thermal conductivity of the base. The base is greater than the thermal conductor in the longitudinal direction of the fixing rotator. The base includes a groove that is disposed outboard at least from the thermal conductor in the longitudinal direction of the fixing rotator.

Abstract: A fixing device includes a fixing rotator that is flexible, endless, and rotatable. A heater heats the fixing rotator. A pressure rotator is disposed opposite the fixing rotator. A nip former defines a fixing nip between the fixing rotator and the pressure rotator. A support supports the nip former. The nip former includes a back face that contacts the support and has a nonlinear shape in a longitudinal direction of the nip former.

Abstract: A fixing device includes a fixing rotator and a pressure rotator that is disposed opposite the fixing rotator. A nip former is disposed inside a loop formed by the fixing rotator and disposed opposite the pressure rotator via the fixing rotator to form a fixing nip between the fixing rotator and the pressure rotator. The fixing rotator slides over the nip former. A flange supports the fixing rotator at both lateral ends of the fixing rotator in a longitudinal direction of the fixing rotator. The nip former includes a base and a thermal conductor that has a thermal conductivity greater than a thermal conductivity of the base. The base is greater than the thermal conductor in the longitudinal direction of the fixing rotator. The base includes a groove that is disposed outboard at least from the thermal conductor in the longitudinal direction of the fixing rotator.

Abstract: A fixing device includes an endless fixing rotator, a heater, a nip formation assembly, and an opposed rotator. The endless fixing rotator is rotatable in a direction of rotation. The heater heats the fixing rotator. The nip formation assembly is disposed opposite an inner circumferential surface of the fixing rotator. The opposed rotator is pressed against the nip formation assembly via the fixing rotator to form a fixing nip between the fixing rotator and the opposed rotator. The nip formation assembly includes a nip former to contact the inner circumferential surface of the fixing rotator, maintain a constant thickness against pressure from the opposed rotator, and transfer heat. The opposed rotator is shorter than the nip former in a longitudinal direction of the opposed rotator. The opposed rotator is disposed within an area opposite the nip former.

Abstract: An image forming apparatus includes a fixing device that includes a heater to heat a fixing rotator, an opposed rotator to press against the fixing rotator to form a fixing nip therebetween, and at least one rotary body to convey a recording medium to the fixing nip. A controller rotates the fixing rotator in a forward direction to fix a toner image on the recording medium. The controller stops the heater and rotates the fixing rotator in a predetermined rotation direction when a failure occurs while the fixing device is activated. The controller determines that the predetermined rotation direction is the forward direction or a backward direction according to the at least one rotary body that sandwiches the recording medium, if the fixing nip and the at least one rotary body sandwich the recording medium simultaneously when the failure occurs while the fixing device is activated.

Abstract: A fixing device includes a fixing rotator and a lateral end heater to heat a lateral end span of the fixing rotator in an axial direction thereof. A thermal conduction aid contacts the fixing rotator. A nip formation pad contacts the thermal conduction aid. A lateral end temperature detector detects a temperature of the fixing rotator in a lateral end detection span in the axial direction of the fixing rotator. The thermal conduction aid contacts the nip formation pad in a first span including the lateral end detection span in the axial direction of the fixing rotator with a first contact area. The thermal conduction aid contacts the nip formation pad in a second span disposed outboard from the first span in the axial direction of the fixing rotator with a second contact area smaller than the first contact area.