FIXING DEVICE AND IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide a fixing device of an electromagnetic induction heating system having high heat generating efficiency at a low cost.SOLUTION: A side core 44 is disposed along a straight line extending in the radial direction from the shaft of a heating roller 51 and the end surface 44a of the side core 44 opposed to the outer peripheral face of the heating roller 51 is roughly perpendicular to the straight line. Thus, a magnetic flux B, which diffuses so as to form a parabola as is away from the core, substantially passes through the heating roller 51. In this manner, the area of the side core 44 facing to the heating roller 51 may easily increased by using an I-shaped side core capable of obtaining a constant dimensional precision and the heat generation efficiency may be increased by reducing leakage magnetic flux which does not pass through the heating roller 51.