| 摘要 |
PROBLEM TO BE SOLVED: To prevent deterioration in picture quality due to dirt on a pressure roller over a long term. SOLUTION: The temp. rising rate ΔT/Δt is calculated at every 100 msec based on a detection temp. of a thermistor. This is compared with the temp. rising rate (a) measured beforehand by a 100 V input (S4), and when the ΔT/Δt is smaller than (a), the wavenumber or the phase angle of an input control is changed, and power is increased (S5). On the other hand, when the ΔT/Δt exceeds (a) in S4, the wavenumber or the phase angle of the input control is changed, and the power is reduced (S6). Thereafter, until the ΔT/Δt becomes (a) or below (S7), the power reduction (S6) is repeated, and when the ΔT/Δt becomes (a) or below, the increase/decrease in the power is adjusted, and when a count t of a timer exceeds t' (S8), and the input control is changed to the control at a first control temp. T1. Thus, since a temp. difference between a fixing film and the pressure roller is reduced, the dirt transferred from the fixing film to the pressure roller is prevented. |
