HEATING DEVICE AND FUSER UTILIZING ELECTZROMAGNETIC INDUCTION

摘要

Heating utilizing electromagnetic induction is provided by an induction heating unit (180) that is opposed to a heating member (130, 150) and causes the heating member to heat through (130, 150) eddy currents. The induction heating unit has an exciting coil (220) for generating a magnetic field and a coil guid member (200) on which the exciting coil is wound. The exciting coil is formed in at least two layers in such a manner that a first layer is formed on a circumferential surface of the coil guide member by winding a plurality of turns and a second layer is formed around and outside the first layer on the side opposite to the coil guide member, and winding of each of the second layer and following layers is started from a position close to the winding start position of the first layer in order to decrease current leakage between the layers. Also, the exciting coil (220) is wound in more lares on a top portion of a pyramid-shaped support (190) than on a foot portion thereof, to provide efficiently a tight winding.