Patent ID: 8050583

Claim:
A fixing device, comprising: a fixing roller; a heat roller including a first heat source and a second heat source, the first heat source including a first halogen heater configured to primarily irradiate a center portion of a paper feed area and the second heat source including a second halogen heater configured to primarily irradiate an end portion of the paper feed area; a fixing belt stretched around the fixing roller and the heat roller; a pressure roller comprising a pressure heat source including a third halogen heater and configured to rotate in press contact with the fixing roller; a first temperature detector configured to detect a temperature of the center portion of the paper feed area on the fixing belt, which is used to control activation of the first heat source based on a first set temperature of the center portion; a second temperature detector configured to detect a temperature of the end portion of the paper feed area on the fixing belt or a temperature of the fixing belt outside the paper feed area, which is used to control activation of the second heat source based on a second set temperature of the end portion; and a pressure temperature detector configured to detect a temperature of the paper feed area on the pressure roller, which is used to control activation of the pressure heat source based on a third set temperature of the paper feed area, wherein the halogen heaters are configured to be switched on and off at regular intervals according to a cycle to reduce power consumption, and at least one of the halogen heaters is controlled according to the cycle during paper feed; a duty ratio of the first heat source is increased by an amount corresponding to a wattage used for the second heat source when the temperature detected by the second temperature detector is at or above the second set temperature during paper feed; and a duty ratio of one of the second heat source and the pressure heat source is increased by an amount corresponding to a wattage used for the first heat source when the temperature detected by the first temperature detector is at or above the first set temperature during paper feed.