There is used an image forming apparatus including a fixing unit configured to heat a recording material at a fixing nip portion to fix a toner image, and a control unit configured to switch a target temperature, wherein, in the case where the target temperature of preceding recording material is first temperature, the target temperature of subsequent recording material is second temperature which is higher than the first temperature, and a difference between the second temperature and the first temperature has a first value, the control unit performs switching from timing which is earlier than reaching of the second recording material to the fixing nip portion by a predetermined period, and, the higher the target temperature of the preceding recording material, the shorter the predetermined period.

An image forming apparatus includes an accommodating portion, an image forming unit, a skew correcting portion, a conveyance unit, a detection unit, a re-conveyance unit, and a control unit. The control unit controls the re-conveyance unit such that the re-conveyance unit stops a sheet in the second conveyance path temporarily and starts to convey the sheet at a first timing after a second timing and before a third timing, where the second timing is a timing such that if the sheet is started to convey to the first conveyance path at the second timing, the conveyance unit decelerates the conveyance speed when the sheet reaches to the detection unit, and the third timing is a timing such that if the sheet is started to convey to the first conveyance path at the third timing, the conveyance unit decelerates the conveyance speed when the sheet reaches to the skew correcting portion.

An image forming apparatus includes an image bearing member, an image forming portion, an endless belt, a plurality of stretching rollers including an inner roller, an outer roller, a position changing mechanism capable of changing a position of the inner roller to a first position and a second position positioned downstream of the first position with respect to a rotational direction of the endless belt, a feeding member, a feeding member driving portion, and a controller. A feeding start timing of a recording material by the feeding member depends on the position of the inner roller during transfer of a toner image onto the recording material.

A transport apparatus includes: a transport mechanism that transports a medium manually inserted; and a control unit that changes, depending on a type of the medium, a start timing of transporting the medium.

An image forming apparatus includes a conveying unit, an image forming unit, a fixing unit, a first driving unit, a second driving unit, a transmission unit to transmit an ultrasonic wave, and a reception unit. Where a determination is made that a timing at which excitation of the first driving unit is switched or a timing at which excitation of the second driving unit is switched overlaps with a timing to obtain a value of the ultrasonic wave received by the reception unit, the transmission unit does not transmit an ultrasonic wave. Where a determination is made that the timing at which the excitation of the first driving unit is switched or the timing at which the excitation of the second driving unit is switched does not overlap with the timing to obtain the value of the received ultrasonic wave, the transmission unit transmits an ultrasonic wave.

An image forming device includes a sheet feeding device, an image forming part, a fixing device, a conveyance path, a first sensor and a second sensor. The first sensor is disposed on the conveyance path on a downstream side of the fixing device in the conveyance direction and detects the sheet passed along the conveyance path. The second sensor is disposed on the conveyance path on an upstream side of the fixing device in a conveyance direction and detects the sheet passed along the conveyance path. The fixing device stops a driving of a heating source and stops a rotation of a fixing belt when the first sensor does not detect the sheet passing properly. The fixing device stops the driving of the heating source and stops the rotation of the fixing belt after a predetermined period when the second sensor do not detect the sheet passing properly.

An image forming apparatus includes a conveying unit, an image forming unit, a fixing unit, a first driving unit, a second driving unit, a transmission unit to transmit an ultrasonic wave, and a reception unit. Where a determination is made that a timing at which excitation of the first driving unit is switched or a timing at which excitation of the second driving unit is switched overlaps with a timing to obtain a value of the ultrasonic wave received by the reception unit, the transmission unit does not transmit an ultrasonic wave. Where a determination is made that the timing at which the excitation of the first driving unit is switched or the timing at which the excitation of the second driving unit is switched does not overlap with the timing to obtain the value of the received ultrasonic wave, the transmission unit transmits an ultrasonic wave.

In an image forming apparatus, when a first sheet and a second sheet are subjected to printing and the second sheet is being conveyed at a particular timing after a sheet sensor detected passage of a trailing end of the first sheet, and when a sheet interval between the first sheet and the second sheet is equal to or greater than a particular threshold interval, a controller positions first and second developing rollers to first and second separated positions, respectively, after developing of images to be transferred onto the first sheet has been completed, positions the developing rollers to be used for printing on the second sheet to respective contact positions, and starts developing images to be transferred on the second sheet. The controller is further configured to perform a color printing using both the first and second developing rollers, and a monochromatic printing using only the second developing roller.

An image forming apparatus includes an image forming unit, a storage portion to which a heating unit configured to heat the sheet stored in the storage portion is detachably attached, a conveyance unit, a detection unit configured to detect attachment of the heating unit to the storage portion, and a control unit configured to control the conveyance unit such that a standby time by which conveyance of the sheet fed from the storage portion is stopped is shorter when the detection unit detects the heating unit than when the detection unit does not detect the heating unit.

According to one embodiment, an image forming apparatus includes: a registration roller; a motor configured to drive the roller; and a controller configured to control the motor. The roller is disposed at a first position on a conveyance path of paper on which an image is to be formed, and sends out the paper toward a second position on the conveyance path. The second position is downstream from the first position on the conveyance path and is an image transfer position on the paper. The controller controls the motor by using both speed control and position control when the leading end of the paper is at a position from the first position to the second position, and controls the motor by using only the speed control when the leading end of the paper reaches the second position.