PURPOSE: To prevent the noise at the time of the release operation of pinch roll press-fixing by providing a pinch cam with the first cam curve and the second cam curve which are continuous and constituting the connection part between two cam curves with an arc connecting both cam curves.

CONSTITUTION: The press-fixing cam part of a pinch cam 5 consists of a minimum cam radius part 5a, the first cam curve 5b1, an arc part 5r1, the second cam curve 5b2, and a maximum cam radius part 5c. Consequently, a conventional angular part formed at the intersection between the first cam curve 5b1 and the second cam curve 5b2 is substituted with the arc part 5r1, and the arc part 5r1 smoothly connects both cam curves because being brought into contact with the first cam curve 5b1 and the second cam curve 5b2. A slide part 7a of a press-fixing cam follower 7 is smoothly slided because of the arc part 5r1 even in case of switching from the first cam curve to the second cam curve when the slide part 7a is slided along the press-fixing cam part of the pinch cam 5, and thus, the influence of pressing force due to a press- fixing spring 8 is reduced to prevent the occurrence of noise in a driving gear part, the quick change of a load, the abnormal operation, etc.