| 摘要 |
PURPOSE:To make the heat generation efficiency and heating distribution of the titled device uniform by providing an electric insulating layer which has a difference of >=10<1> order in volume-resistance ratio from the in-use volume resistance of a heating layer having positive resistance temperature characteristics(PTC). CONSTITUTION:Heating layers 4 and 4 which have PTC characteristics after being sintered and have electrodes 5A and 5B formed on their surface are provided in the axial direction of a roller. Then, the insulating layer 49 which has a difference of >=10<1> order in volume-resistance ratio from the in-use volume resistance of the PTC heating layers 4 and 4 are provided outside it. Further, the insulating layer 49 is provided on a metallic cylindrical roller 50. The upper heating layer 4 and an internal surface layer 7 are insulated electrically from the base body of the roller 50. This insulating layer 49 increases the heating efficiency of the PTC ceramic of the upper layer. Thus, irregularity in heating is prevented and the heat conversion efficiency of electric power is improved. |
