Patent ID: 9651903
Date: 2017-05-16
CPC Classifications: G03G

Claim:
1. A fixing device comprising: an alternating current power supply; plural heaters each fixing an image on a sheet; a switching unit that switches from a turn-on state of the heaters in which the heaters are connected to the alternating current power supply to a turn-off state of the heaters in which the heaters are disconnected from the alternating current power supply or from the turn-off state of the heaters to the turn-on state of the heaters; and a control unit that controls the switching unit to switch under a turn-on/off pattern with a half wave interval of the alternating current power supply being constituted as a unit thereof and to turn on or off the plural heaters, wherein when changing the turn-on/off pattern, the control unit sets a control interval as a period of switching time in the turn-on/off pattern so as to be longer than a first period of time that does not exert any influence to a flicker value and to be shorter than a second period of time that does not exert any influence to a response to temperature control or the control unit selects a third turn-on/off pattern in which power difference between power of a first turn-on/off pattern before the change in the turn-on/off pattern and power of a second turn-on/off pattern after the change in the turn-on/off pattern is smaller than a set reference power difference.