Patent ID: 6584298
Filing Date: 2003-06-24
Classification: G03G,H05B

Abstract:
A fixing device comprising:(a) a cylindrical fixing roller to be heated; (b) a coil supporting member disposed along an inside of the fixing roller; (c) a heat applying coil formed by winding a wire around a circumference of the coil supporting member for heating the fixing roller by inducing an induced current in the fixing roller; and (d) a pressing roller for forming a nip portion with the fixing roller, and for conveying a transfer material which is gripped by the nip portion between the fixing roller and the pressing roller, so that a toner image formed on the transfer material is fixed by heat energy from the fixing roller, wherein the heat applying coil is formed by winding the wire in a longitudinal direction of the coil supporting member so as to have a shape which has parts lying parallel to the longitudinal direction of the coil supporting member and parts lying along the circumference of the coil supporting member, and so that a winding density of the parts lying along the circumference of the coil supporting member is made higher than a winding density of the parts lying parallel to the longitudinal direction of the coil supporting member; and wherein the wire of the heat applying coil has a cross-sectional shape such that a length of a major axis and a length of a minor axis intersecting each other perpendicularly at a center of the cross-sectional shape are different from each other, and the heat applying coil is formed by winding the wire so that adjoining major axes of the cross-sectional shape face each other in the parts lying parallel to the longitudinal direction of the coil supporting member, and so that adjoining minor axes of the cross-sectional shape face each other in the parts lying along the circumference of the heat applying coil.