Patent ID: 7693439
Filing Date: 2010-04-06
Classification: G03G,G05D

Abstract:
1. A fixing device, comprising: a pair of rotating members forming a nip therebetween to fix a toner image on a recording medium by transferring the recording medium through the nip; a heater to heat at least one of the pair of rotating members to a process temperature when driven with an alternating current supplied from a current source; a detector to detect a process temperature and to output a detection signal indicating the process temperature; a calculator to calculate an amount of heat to adjust the process temperature to a reference temperature according to the detection signal and to output a signal indicating the calculated amount of heat thereafter being output; a pulse width modulation circuit to generate, according to the signal output from the calculator, a drive signal having a pulse width modulation cycle divided into a first off time, a second off time, and an on time between the first and second off times, the first and second off times each being a period in which the alternating current remains unsupplied to drive the heater, and the on time being a period in which the alternating current is supplied to drive the heater; and a controller to control operation of the heater according to the drive signal, wherein the signal output from the calculator is a pulse signal having a pulse width proportional to the calculated amount of heat.