ELECTROMAGNETIC INDUCTION TYPE HEATING DEVICE

PURPOSE:To enhance the heating efficiency by installing rolls of ferro-magnetic substance as a guide for sheets between magnetic poles which are situated oppositely with the sheet interposed, and thereby precluding the sheet from warping in the direction across the width. CONSTITUTION:Rolls 4a-4d as a guide for sheets 1 transported are installed between magnetic poles 21, 31, and sheets are guided zigzagged. Each roll 4 has a roll part 41 in laminate of ferro-magnetic substance, and its length shall be greater than the width of sheet 1, to prevent it from warping in the direction across the width while lying within this heater device concerned. Forming each roll member 41 from ferro-magnetic substance allows the rolls 4a-4b to work as yoke in the magnetic circuit, which should decrease greatly the inter-mag. pole distance in magnetical terms. Further the heating efficiency for the sheet 1 becomes higher with decreasing inter-mag. pole distance in magnetical terms. this accomplishes elimination of warps of sheet 1 and enhances the heating efficiency.