Approaching laying out body of revolution

摘要

PROBLEM TO BE SOLVED: To suppress an excessive temperature rise in a non-paper passing area on a fixing roller, regarding an electromagnetic induction-heating fixing device.;SOLUTION: An exciting coil 31 is disposed along the circumferential direction of the fixing roller 1 in an axial direction, and twelve main cores 34 are disposed at predetermined intervals outside the coil 31. Core heaters 37a to 37d are stuck to four main cores 34 located closer to each end of the roller among the main cores 34. Temperature sensors 61 and 63 for detecting the surface temperature of the fixing roller 1 are disposed. When each temperature detected by the temperature sensors 62 to 64 becomes equal to or higher than a predetermined upper limit temperature during fixation, the portions detected by the sensors as portions having the equal or higher temperature are estimated as the non-paper passing area, then, each core heater located on the corresponding position is turned on so as to heat up until the temperature of the corresponding main core 34 exceeds Curie temperature, and the magnetic flux density in the non-paper passing area is reduced, consequently, heating is suppressed.;COPYRIGHT: (C)2009,JPO&INPIT