| 摘要 |
PROBLEM TO BE SOLVED: To output an image with high quality by always optimizing a fixing nip pressure even if it is changed with time due to deterioration of a member or the like. SOLUTION: A fixing device includes endless pressure belt 120 and heating belt 130, and optimizes a pressurizing force by a fixing nip part between both belts. An adjustment mode is entered upon detection of a change in fixing nip pressure. A pressure sensitive sheet which shows a coloring reaction according to the pressurizing force is fed, and pressure information is read therefrom by an image reading means to obtain "density information ". A control means arithmetically compares a density reference value with a density measurement value obtained in the pressure sensitive sheet P, and transmits an operation signal according to the difference between both values to an adjustment means, whereby the adjustment means is operated to rotate a pressurizing cam 170 to a suitable phase angle position. The pressure contact force of a lever member 171 with the pressurizing roller 121 is changed by the rotation of the pressurizing cam 170 to readjust the fixing nip pressure with the heating belt 130 side to a set optimum pressure. COPYRIGHT: (C)2009,JPO&INPIT
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