| 摘要 |
<p>PURPOSE:To prevent the generation of curling on printed paper sheets by changing a fixing nip pressure in accordance of the curling tendency of the printed paper sheets. CONSTITUTION:A fixing nip pressure changing means 4 for changing a pressure between a heating roller 1 and a backup roller 2 is provided. By reducing a fixing nip pressure applied to a printed paper sheet 3 on the heating roller 1 and the backup roller 2 by means of this fixing nip pressure changing means 4, the generation of curls of the printed paper sheet to be easily curled is limited. Then, when printing is made on another paper sheet difficult to be curled or having no curls, a fixing nip pressure is only to be returned to a normal value. When fixing of a toner image is sufficient, or when it is necessary to fix it strongly, the fixing pressure is increased. For a part where curls are easily generated to a printed paper sheet 3 the fixing nip pressure is made small and for a part where there is no problem of curls, the fixing nip pressure is added as usual.</p> |
