Patent ID: 8547412

Claim:
An image forming apparatus comprising: a light source configured to emit a light beam; a photosensitive member configured to carry a toner image; a brushless motor comprising: a stator in which a plurality of coils are placed; and a rotor in which a plurality of magnets are placed; a rotary polygon mirror, which is rotated by the brushless motor, and which is configured to periodically deflect the light beam emitted from the light source to sequentially form scanning lines on the photosensitive member; an energization switching unit configured to turn on and off energizations of the coils; a voltage detecting unit configured to output a detection signal based on induced voltages that are generated in the coils by rotation of the rotor; a motor controlling unit configured to control the turning on/off of the energizations by the energization switching unit based on the detection signal; a fixing unit configured to thermally fix the toner image transferred to a recording medium from the photosensitive member; and a heat controlling unit that is configured to: perform a fixing temperature control, during the image forming operation, in which a temperature of the fixing unit is maintained at a fixable temperature; and stop the fixing temperature control in a non-image forming period, wherein, in a non-image forming period after one image forming operation is ended, the motor controlling unit performs a low-speed process, and wherein, in the low-speed process, the motor controlling unit is configured to maintain a rotation speed of the brushless motor at a speed, which is less than a speed in the image forming operation, and at which the induced voltages are detectable by the voltage detecting unit, wherein, in the low-speed process, the motor controlling unit is further configured to: maintain the rotation speed of the brushless motor at a first rotation speed, which is less than the speed in the image forming operation, until the temperature of the fixing unit becomes less than a first temperature; decrease the rotation speed of the brushless motor, when the temperature of the fixing unit becomes less than the first temperature, from the first rotation speed to a second rotation speed at which the induced voltages are detectable by the voltage detecting unit; and maintain the rotation speed of the brushless motor at the second rotation speed until the temperature of the fixing unit becomes less than a second temperature.