PURPOSE: To constantly attain a stable fixing operation by switching the press- contacting force of a heat roller and a press-fixing roller to low when a set number of recording sheets of a prescribed size are fixed.
CONSTITUTION: If the surface temperature of a heat roller is high at a point S and fixing is started at the press-contacting force PI, the surface temperature of the heat roller is gradually lowered as the recording sheets of the prescribed size are continuously fixed. Finally a set number n1 of recording sheets are fixed and the temperature arrives at a point C. Then, the press-contacting force is switched to a low pressure P2 at the point C. Thus since the press- contacting force when the recording sheet passes between the heat roller and a press-fixing roller is reduced, heat quantity taken away by the recording sheet is reduced. Resultantly, temperature lowering on a heat roller surface is stopped and the temperature on the heat roller surface is again in a rising condition. Therefore, the fixing operation is performed to the last (a point F) at the press-contacting force of the low pressure P2.
| JP3678060 | TONER AND IMAGE FORMING METHOD |
| JPH06130848 | FIXING DEVICE |
SASAKI HIROBUMI
SAITO TAKU
MIWA TADASHI
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