| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent an occurrence of dead time in operating a fixing device by controlling separation amount between a pressure roller and a fixing roller in consideration of a case where the fixing device is used with a lower probability of occurrence for a toner blister. <P>SOLUTION: A stepping motor 26 for rotationally driving a cam 24 is stopped at any position between a nip pressurization state and a nip release state from a cam phase signal detection position. In the nip release state, a pressure roller 15 and a fixing roller 13 are separated from each other by a set separation amount t. The separation amount t is adjusted or set by changing the stop position of the cam 24. A sensor 31 for detecting a surface temperature of the pressure roller 15 is brought into contact with a surface of the pressure roller 15 to detect a surface temperature k of the pressure roller 15 except for a period of an image formation, and to adjust the separation amount t, thereby preventing temperature rise of the pressure roller 15 which is disadvantage to a toner blister, and preventing the first printing time from getting longer when the fixing device is used with a lower probability of occurence for the toner blister. <P>COPYRIGHT: (C)2012,JPO&INPIT |
