US 7,529,515 B2
Image forming apparatus and fixing apparatus
Yoshinori Tsueda, Fuji (Japan); Satoshi Kinouchi, Tokyo (Japan); Osamu Takagi, Chofu (Japan); and Toshihiro Sone, Yokohama (Japan)
Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan); and Toshiba Tec Kabushiki Kaisha, Tokyo (Japan)
Filed on Apr. 30, 2008, as Appl. No. 12/112,663.
Application 12/112663 is a division of application No. 11/080833, filed on Mar. 16, 2005, granted, now 7,369,801.
Prior Publication US 2008/0247790 A1, Oct. 09, 2008
Int. Cl. G03G 15/20 (2006.01); G03G 15/16 (2006.01)
U.S. Cl. 399—328  [399/33; 399/122] 12 Claims
OG exemplary drawing
 
1. An image forming apparatus comprising:
an image carrier which holds a developer image in an electrostatic manner; and
a fixing apparatus which fixes the developer image onto a recording medium to which the developing material image has been transferred, the fixing apparatus comprising:
a heating unit including a first roller fixed at a predetermined position and rotated by a drive mechanism;
a pressuring unit including a second roller being pressed against the heating unit;
an elastic layer formed at least at one of the first roller and the second roller;
a conductive layer formed outside of the elastic layer;
an inductive heating device including a coil, the inductive heating device supplying inductive heating to the conductive layer by a magnetic field generated from the coil, thereby heating the conductive layer; and
a hardness change detecting mechanism which detects a hardness change of the first roller or the second roller, the hardness change detecting mechanism including a switch configured to be depressed to detect an expansion of the first roller or the second roller.