Induction heating device with orthogonal coils

Abstract

There are provided a first excitation coil that is wound so as to have an axis in the same direction as that of a shaft of a heating roller and that is connected to a first power source, and a second excitation coil that is wound so as to have an axis in a direction substantially orthogonal to the shaft of the heating roller and that is connected to a second power source. The second excitation coil has parallel portions that extend in parallel to an axial direction of the first excitation coil and two folded sections provided at respective ends of the parallel portions. The two folded sections are provided along a circumference of the first excitation coil in such a way that circular arcs of the respective folded sections become opposite in direction to each other. Thus, the maximum available power is increased. When rapid warm-up is required, heating is caused by a coil connected to the auxiliary power source, to thus shorten a warm-up time. Occurrence of a temperature drop at the ends of the heating roller is prevented, to thus enhance energy efficiency. In ordinary situations other than the rapid warm-up operation, recharging can be performed by use of the coil.