| 摘要 |
PROBLEM TO BE SOLVED: To select an optimal fixing mode even when information including the number of processed sheets which is necessary for selecting a fixing mode, is not determined before starting image processing.SOLUTION: After a lapse of warm-up time F1, a quick heat mode characteristic curve S retains a substantially directly proportional characteristic at a gradient depending on P1. After a lapse of warm-up time W+F2, a heat storage mode characteristic curve C retains a substantially directly proportional characteristic at a gradient depending on P2. The quick heat mode characteristic curve S has the larger gradient than the gradient of the heat storage mode characteristic curve C. Both the curves have different gradients P1 and P2 so as to cross with each other at a certain period. A cross-point K becomes a border line (the number of processed sheets N0 value) of selecting a fixing mode (substantially 10 sheets). When the number of processed sheets is known, the quick heat mode is selected till 10 sheets on the basis of an expression (1)', and the heat storage mode is selected from 11 sheets or more, (1)': F1+P1×N≤W+F2+P2×N. |
