| 摘要 |
PROBLEM TO BE SOLVED: To provide a fixing device capable of accurately suppressing abnormal temperature rise in a no-paper passing region and an image forming apparatus using the fixing device.SOLUTION: A detected temperature T1 when starting warming-up, in the paper passing region of a heating roller and a detected temperature T2 after two seconds from the start of warming up are obtained (steps S12 and S15), to obtain a difference &Dgr;T=T2-T1 between the detected temperature T1 and the detected temperature T2 (step S16). An elapsed time from the start of warming up is clocked by an energization timer (step S13). When a print signal is received, the paper passing width of a recording sheet is obtained (step S19:YES and S20). The value of a threshold temperature in a demagnetization coil switching basic table is corrected based on the paper passing width of the recording sheet, the elapsed time from the start of warming up, and the value of the &Dgr;T (step S22). The ON/OFF control of a demagnetization coil is executed based on the corrected threshold temperature and the detected temperature in the non-paper passing region (step 24). |
