An image forming apparatus includes: a pair of transport rollers that nip and transport a recording medium; an image forming device that is disposed on the downstream side of the pair of transport rollers in a recording-medium transport direction and forms an image on the recording medium; a pair of fixing members that are disposed on the downstream side of the image forming device in the recording-medium transport direction and fix the image formed on the recording medium while nipping and transporting the recording medium; a single driving source that rotationally drives both the pair of transport rollers and the pair of fixing members; and a releasing device that stops rotational driving of the pair of transport rollers by the driving source at a timing when the recording medium is transported while being nipped both between the pair of transport rollers and between the pair of fixing members.

An image forming apparatus includes an image bearing member, a transfer portion, a fixing portion, a first sheet feeding portion including a first belt portion for forming a first feeding surface, a second sheet feeding portion including a second belt portion for forming a second feeding surface, a height detecting portion for outputting a signal depending on a height of a sheet from the first feeding surface at a detecting position, and a controller for receiving the signal outputted from the height detecting portion and for controlling the fixing portion.

An image forming apparatus includes a control unit configured to perform a first mode, a second mode, and a third mode. The first mode is a mode in which a sheet conveyance unit is controlled so that an arrival time from a passage of a trailing edge of a preceding sheet through a nip portion to an arrival of a leading edge of a succeeding sheet succeeding to the preceding sheet at the nip portion becomes a first time. The second mode is a mode in which the sheet conveyance unit is controlled so that the arrival time becomes a second time. The third mode is a mode in which the sheet conveyance unit is controlled so that the arrival time becomes a third time. The second time is longer than the first time, and The third time is longer than the second time.

An image formation apparatus according to an embodiment may include a fixation device and a controller. The fixation device includes: a fixation member includes a first region and a second region located closer to a center in a longitudinal direction of the fixation member than the first region; a pressurizing member that forms a nip portion between the fixation member and the pressurizing member; first and second heat generating portions that heat the first and second regions, respectively; a first sensor that detects a first temperature of one of the pressurizing member and the fixation member at a position corresponding to the first region; and a second sensor that detects a second temperature of the one at a position corresponding to the second region. The controller controls a drive speed of the pressurizing member or the fixation member based on the first and second temperatures.

A fixing device includes a heated rotational body, a heating unit, a pressing rotational body, a drive unit, a light emitting unit, a light receiving unit, and a drive control part. The heated rotational body has a reflection member. The drive unit rotates the pressing rotational body. The light emitting unit emits infrared light. The light receiving unit receives the infrared light reflected on the reflection member, and receives radiation light of the heated rotational body. The light receiving unit detects a temperature of the heated rotational body based on a receiving of the radiation light. The drive control part obtains a rotational speed of the heated rotational body based on a light receiving period of the infrared light in the light receiving unit and a circumference determined depending on the temperature of the heated rotational body, and controls the drive unit based on the obtained rotational speed.

An image forming apparatus is provided with a sheet conveying device, a transfer device, a fixing device, a temperature sensor, a temperature control portion, and a conveyance control portion. The temperature control portion regulates power supplied to the heater by comparing between a temperature measured by the temperature sensor and a preset target temperature. The temperature control portion sets the target temperature to a first target temperature when an operation mode is a normal mode, and to a second target temperature lower than the first target temperature when the operation mode is a special mode. In a case in which the sequential printing process is performed, the conveyance control portion makes the sheet conveying device convey sheets at a longer interval when the operation mode is the special mode than when the operation mode is the normal mode.

A sliding member is a tubular member surrounding a base member, and allows, by rotation, its lubricant-coated inner surface to slide in a sheet conveyance direction with respect to a surface of the base member. A heater heats the sliding member. A pressure roller forms a nip between the pressure roller and the sliding member and makes, by rotation, the sliding member rotate following the rotation. A temperature sensor measures a temperature of the base member or the sliding member. A roller driving device rotates the pressure roller at a preset initial speed and subsequently at a normal speed higher than the initial speed, in a temperature-rise process in which the temperature measured by the temperature sensor is raised to a target temperature by operation of the heater.

A fixing device includes a heated rotational body, a heating unit, a pressing rotational body, a pressing mechanism, a drive unit, a position recognition part, a rotational state determination part, a drive control part, and a pressing control part. The heated rotational body has a pattern. The position recognition part is configured to recognize a specific point contained in the pattern at a prescribed period. The rotational state determination part is configured to determine a variation in a rotational speed of the heated rotational body and a meandering state of the heated rotational body based on a position of the specific point recognized at the prescribed period. The drive control part is configured to control the drive unit based on the variation in the rotational speed. The pressing control part is configured to control the pressing mechanism based on the meandering state.

An image forming apparatus includes: a first rotatable member; a second rotatable member that presses against the first rotatable member in a pressed state and separates from the first rotatable member in a separated state; and a hardware processor that sets a target speed of the second rotatable member based on a change in speed of the second rotatable member between a first speed in the separated state and a second speed in the pressed state.

The present invention relates to an electrostatic charge image developing toner having a ratio of TP2/TP1 of 1.47 to 2.35, wherein a first measurement value of a tan δ maximal value measured in 40° C. to 80° C. by a rheometer is set as the TP1, and a second measurement value of a tan δ maximal value measured in 40° C. to 80° C. by the rheometer is set as the TP2.