COIL, HEATING DEVICE, AND IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide a coil formed by winding a conductive wire overlapped from the inner circle to outer circle side, with an increased number of magnetic fluxes passing in a zone of a surface enclosed by the conductive wire on the inner circle side and with an extended length of a magnetic path extending along a shorter side of the zone.SOLUTION: A coil 53 is formed by winding a stranded wire around an air core zone Rv for plural turns so as to internally form the air core zone Rv. The stranded wire constituting the coil 53 has a cross-section with its width greater than the thickness. When being wound in a longitudinal direction of the air core zone Rv, the stranded wire is wound in overlap in the width direction. As a result, the length of the overlap in a part where the wire is wound in the longitudinal direction is Lr that is proportional to the number and width of the stranded wire. When being wound in the shorter direction of the air core zone Rv, the stranded wire is wound in overlap in the direction of thickness. As a result, the length of overlapping the stranded wire is Lx that is proportional to the number and thickness of the stranded wire in a part where the wire is wound along the shorter direction.