US Patent 7664415 Fixer, image forming apparatus, and image forming method

A fixer for an image forming apparatus includes a fixing member configured to fuse a toner image with heat, a pressure member configured to press against the fixing member to form a nip therebetween, and a control unit configured to control a relative pressure of the pressure member against the fixing member. The control unit includes a cam configured to change a rotation position thereof to change the relative pressure of the pressure member against the fixing member, a driving source configured to drive the cam to rotate, and a controller configured to detect a rotation position of the cam by detecting changes in an electrical current that flows in the driving source when the cam is rotated, and control the rotation position of the cam.