Patent ID: 6907203

Claim:
A method of controlling a fusing temperature of a fusing roller in an electrophotographic imaging apparatus, the fusing roller having a cylindrical roller, a heater heating the cylindrical roller, and a rubber layer formed on a surface of the cylindrical roller with a predetermined thickness, the method comprising: determining whether a predetermined new power control period starts; upon determining that the new power control period starts, calculating a power supply ratio corresponding to a power to be supplied to the heater during the new power control period with respect to a maximum power that can be supplied to the heater; upon determining that the calculated power supply ratio is greater than zero, supplying the power to the heater during the new power control period according to the power supply ratio; and upon determining that the calculated power supply ratio is not greater than zero, repeating the operations of determining whether the predetermined power control period starts, calculating the power supply ratio, and supplying the power to the heater, wherein the power supply ratio is calculated by adding a predetermined offset value β to a control value that is a product of a predetermined coefficient α and a subtraction of a measured temperature of the fusing roller from a target fusing temperature, and the offset value β is smaller than or equal to a ratio of a power supply with respect to the maximum power supplied to the heater for the new power control period to maintain the measured temperature of the fusing roller at the target fusing temperature when the fusing temperature is around the target fusing temperature.