| 摘要 |
PROBLEM TO BE SOLVED: To provide a fixing device which most suitably controls a fixing process by changing a roll pressure in accordance with the type of toner for use. SOLUTION: Three press-fixing springs 37a to 37c and press-fixing force switching cams 38a to 38c corresponding to these springs respectively are attached to one side of the fixing device. When a press-fixing release lever 39 is in the perpendicular state, a pair of fixing rolls are in the press-fixing state. When the press-fixing release lever 39 is turned clockwise at 45 deg., an arm 40a in the endmost part rises due to the shape of the left part of the cam 38a, and the press-fixing spring 37a is elongated up to a maximum load in accordance with this rise. Since the arm 40a is separated from a bearing 41a at this time, the spring load dependent upon the arm position is released. When the press-fixing release lever 39 is turned clockwise at 45 deg. furthermore, an arm 40b rises due to the shape of the center part of the cam 38b and is separated from a bearing 41b, and therefore the spring load is released. When the press-fixing release lever 39 is turned clockwise at 90 deg. furthermore, press-fixing is released.
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