Abstract: A fixing device includes a fixing rotator and a slider that slides over the fixing rotator. A cam presses the slider against the fixing rotator. The cam includes a cam rear disposed opposite a rear end of the fixing rotator in an axial direction thereof and a cam front disposed opposite a front end of the fixing rotator in the axial direction thereof. A controller rotates the cam to a first slide position where the cam rear presses the slider against the fixing rotator, a second slide position where the cam rear and the cam front press the slider against the fixing rotator, a third slide position where the cam front presses the slider against the fixing rotator, and an isolation position where the cam rear and the cam front do not press the slider against the fixing rotator.

Abstract: Heat-equalizing rotation of a fixing member and a pressing member for equalizing the distribution of the temperature of a surface of the fixing member in a width direction is performed after a recording medium having a size less than or equal to a predetermined size in the width direction passes a nip portion and before a recording medium having a size greater than the predetermined size in the width direction passes the nip portion. Further, a termination condition of the heat-equalizing rotation is selected from among a plurality of different kinds of termination conditions, based on image formation related information related to next image formation performed after the heat-equalizing rotation.

Abstract: An image forming apparatus includes paper trays to contain and feed a recording sheet on which a toner image is transferred; status sensors to detect a storage status of the recording sheet contained in the paper trays; a sheet sensor to detect a smoothness of the recording sheet; a memory to store detection values of the smoothness detected by the sheet sensor; a fixing device to heat and press the toner image transferred onto the recording sheet and fix it onto the recording sheet; and a control circuit to determine a target fixing temperature of the fixing device based on the detection values stored in the memory. The control circuit determines the target fixing temperature for successive recording sheets depending on the detected smoothness, and resets the detection values stored in the memory to zero when the status sensors detect a change in the storage status of the paper trays.

Abstract: A fixing device includes a heat source; a fixing member looped into a generally cylindrical shape to rotate in a circumferential direction thereof and partially heated by the heat source and to heat a surface of a recording medium bearing an unfixed toner image to fix the unfixed toner image thereon in a fixing process; a rotary pressing member disposed facing the fixing member to form a nip therebetween, through which the recording medium is transported in a transport direction; and a rotation driver to rotate one of the fixing member and the pressing member. In a case in which the fixing member is halted for a reason other than the fixing process while power of the fixing device is on, electric power is not supplied to the heat source and the fixing member is rotated by a predetermined amount or more after the fixing member is halted.

Abstract: An image forming apparatus includes a fixing device. The fixing device includes a rotatable endless fixing member, a nip forming member arranged inside the fixing member, a pressing member in contact with the nip forming member via the fixing member, and a heating source configured to heat the fixing member. When an abnormality occurs in at least one of the fixing device and other devices included in the image forming apparatus, a rotation of the fixing member is stopped prior to stopping a rotation driving of a discharging unit and, after stopping, the fixing member is controlled to rotate.

Abstract: A fixing device includes a heat source; a fixing member looped into a generally cylindrical shape to rotate in a circumferential direction thereof and partially heated by the heat source and to heat a surface of a recording medium bearing an unfixed toner image to fix the unfixed toner image thereon in a fixing process; a rotary pressing member disposed facing the fixing member to form a nip therebetween, through which the recording medium is transported in a transport direction; and a rotation driver to rotate one of the fixing member and the pressing member. In a case in which the fixing member is halted for a reason other than the fixing process while power of the fixing device is on, electric power is not supplied to the heat source and the fixing member is rotated by a predetermined amount or more after the fixing member is halted.

Abstract: An image forming apparatus includes a fixing device. The fixing device includes a rotatable endless fixing member, a nip forming member arranged inside the fixing member, a pressing member in contact with the nip forming member via the fixing member, and a heating source configured to heat the fixing member. When an abnormality occurs in at least one of the fixing device and other devices included in the image forming apparatus, a rotation of the fixing member is stopped prior to stopping a rotation driving of a discharging unit and, after stopping, the fixing member is controlled to rotate.

Abstract: When calculating an actual turn-on duty based on a required duty according to a feedback control, the actual turn-on duty is corrected using a correction table or a correction conversion formula such that a required turn-on duty and the actual turn-on duty coincide with each other. A fixing heater is controlled according to the corrected actual turn-on duty.

Abstract: A fixing device capable of shifting to a sleep state includes a heat source; a rotatable fixing member that is partly heated by the heat source to heat an unfixed image carrying surface of a recording medium; a rotatable pressing member that is in pressure contact with the fixing member to form a nip portion between the pressing member and the fixing member; a rotation drive unit that directly or indirectly rotates the fixing member; a temperature detecting unit that detects a temperature of the fixing member; and a controller configured to prohibit the fixing device from shifting to the sleep state when the temperature of the fixing member in a region facing the heat source is equal to or more than a predetermined temperature T1 at a point when a predetermined time period t1 has elapsed from the stop of rotation drive of the rotation drive unit.

Abstract: A fixing device, corresponding to a plurality of sheet passing widths, includes a rotating member configured to convey a recording medium, rise in temperature, and fix toner; temperature sensors configured to detect the surface temperature of the rotating member; heating members including at least one heat generating unit, provided inside the rotating member; and a control unit configured to control a heating state obtained by the heating members. The heat generating units are provided not to overlap each other in the direction of the sheet passing width orthogonal to the recording medium conveying direction. The temperature sensors are only placed at positions corresponding to the heat generating units used when printing on the recording medium having a minimum width. The control unit controls the heating state in accordance with the surface temperature, a sheet passing width, and an operational state of the rotating member that changes with time.

Abstract: A fixing device capable of shifting to a sleep state includes a heat source; a rotatable fixing member that is partly heated by the heat source to heat an unfixed image carrying surface of a recording medium; a rotatable pressing member that is in pressure contact with the fixing member to form a nip portion between the pressing member and the fixing member; a rotation drive unit that directly or indirectly rotates the fixing member; a temperature detecting unit that detects a temperature of the fixing member; and a controller configured to prohibit the fixing device from shifting to the sleep state when the temperature of the fixing member in a region facing the heat source is equal to or more than a predetermined temperature T1 at a point when a predetermined time period t1 has elapsed from the stop of rotation drive of the rotation drive unit.

Abstract: A fixing device capable of shifting to a sleep state includes a heat source; a rotatable fixing member that is partly heated by the heat source to heat an unfixed image carrying surface of a recording medium; a rotatable pressing member that is in pressure contact with the fixing member to form a nip portion between the pressing member and the fixing member; a rotation drive unit that directly or indirectly rotates the fixing member; a temperature detecting unit that detects a temperature of the fixing member; and a controller configured to prohibit the fixing device from shifting to the sleep state when the temperature of the fixing member in a region facing the heat source is equal to or more than a predetermined temperature T1 at a point when a predetermined time period t1 has elapsed from the stop of rotation drive of the rotation drive unit.

Abstract: An optical sensor includes a light-emitting unit to emit light onto a measuring object, a regular reflection light receiver to receive regular reflection light from the measuring object out of the light emitted by the light-emitting unit, and a diffuse reflection light receiver to receive diffuse reflection light from the measuring object out of the light emitted by the light-emitting unit. An angle of incidence of the light emitted onto a surface of the measuring object is not smaller than 75° and not larger than 85°. The diffuse reflection light receiver receives, out of the diffuse reflection light from the measuring object, diffuse reflection light having an angle of reflection with respect to a perpendicular to the surface of the measuring object larger than 0° and smaller than an angle of reflection of the regular reflection light with respect to the perpendicular to the surface of the measuring object.

Abstract: An image forming apparatus includes paper trays to contain and feed a recording sheet on which a toner image is transferred; status sensors to detect a storage status of the recording sheet contained in the paper trays; a sheet sensor to detect a smoothness of the recording sheet; a memory to store detection values of the smoothness detected by the sheet sensor; a fixing device to heat and press the toner image transferred onto the recording sheet and fix it onto the recording sheet; and a control circuit to determine a target fixing temperature of the fixing device based on the detection values stored in the memory. The control circuit determines the target fixing temperature for successive recording sheets depending on the detected smoothness, and resets the detection values stored in the memory to zero when the status sensors detect a change in the storage status of the paper trays.

Abstract: A fixing device includes a controller connected to a heater and at least one of a pressing rotary body and an endless rotary body. The controller performs a first fixing operation, a first transition operation, a second fixing operation, and a second transition operation. The first fixing operation fixes a toner image on a first recording medium after the fixing device is powered on. The first transition operation rotates the pressing rotary body and the endless rotary body while controlling the heater to maintain the endless rotary body at a predetermined temperature for a first duration time. The second fixing operation fixes a toner image on a second recording medium. The second transition operation rotates the pressing rotary body and the endless rotary body while controlling the heater to maintain the endless rotary body at the predetermined temperature for a second duration time smaller than the first duration time.

Abstract: A fixing device includes a rotational member configured to convey and heat a sheet-shaped recording medium, the rotational member including a first heating member and a second heating member provided in parallel to a rotational axis of the rotational member in an interior thereof, the first heating member including a first heat generation part, the second heating member including a second heat generation part and an auxiliary heat generation part adjacent to the second heat generation part, a common temperature sensor configured to sense a temperature of the first heating member and a temperature of the second heating member, and a control part configured to control a ratio of a rate of lighting of the first heating member and a rate of lighting of the second heating member based on the temperature of the first heating member and the temperature of the second heating member.

Abstract: An image forming apparatus includes a fixing device. The fixing device includes a rotatable endless fixing member, a nip forming member arranged inside the fixing member, a pressing member in contact with the nip forming member via the fixing member, and a heating source configured to heat the fixing member. When an abnormality occurs in at least one of the fixing device and other devices included in the image forming apparatus, a rotation of the fixing member is stopped prior to stopping a rotation driving of a discharging unit and, after stopping, the fixing member is controlled to rotate.

Abstract: An image forming apparatus includes a fixing device. The fixing device includes a rotatable endless fixing member, a nip forming member arranged inside the fixing member, a pressing member in contact with the nip forming member via the fixing member, and a heating source configured to heat the fixing member. When an abnormality occurs in at least one of the fixing device and other devices included in the image forming apparatus, a rotation of the fixing member is stopped prior to stopping a rotation driving of a discharging unit and, after stopping, the fixing member is controlled to rotate.

Abstract: A fixing device, corresponding to a plurality of sheet passing widths, includes a rotating member configured to convey a recording medium, rise in temperature, and fix toner; temperature sensors configured to detect the surface temperature of the rotating member; heating members including at least one heat generating unit, provided inside the rotating member; and a control unit configured to control a heating state obtained by the heating members. The heat generating units are provided not to overlap each other in the direction of the sheet passing width orthogonal to the recording medium conveying direction. The temperature sensors are only placed at positions corresponding to the heat generating units used when printing on the recording medium having a minimum width. The control unit controls the heating state in accordance with the surface temperature, a sheet passing width, and an operational state of the rotating member that changes with time.

Abstract: A fixing device includes a heating device to heat an endless rotary body with radiant heat, a power source to supply power to the heating device, a first heat source to heat a region on the endless rotary body corresponding to a width of the small size sheet, and a second heat source to heat regions on the endless rotary body corresponding to both widthwise ends of the large size sheet outside the width of the small size sheet. The power source supplies power only to the first heat source when the small size sheet is printed and to both the first and second heat sources when the large size sheet is printed. The power source supplies more power to the first heat source when the small size sheet is printed than when the large size sheet is printed within a maximum power available to the fixing device.