JPS5729068A - Heating roll for fixing of electrophotographic copier - Google Patents

Abstract

PURPOSE:To make the surface temp. of a heating roll body formed of metal into a cylindrical shape uniformly and reduce the rate of occurrence of fixing defects by providing a sheathed wire in said roll body. CONSTITUTION:Plural through-holes 2 are pierced on the cylinder of a metal-made roll body 1 assuming a cylindrical shape along its axial line at equal intervals, and a sheathed wire 3 is inserted through these holes 2. The wire 3 is of the construction wherein the surface of a nichrome wire is insulated with magnesium oxide powder after which said surface is further coated with a protecting tube consisting of stainless steel. After the wire is folded back into the adjacent through-holes 2 at the end faces on one end side of the body 1, these operations are repeated until one piece of the wire 3 is inserted through all the holes 2. Electric power is applied to both ends of the wire 3. Since the heat generated by the sheathed wire directly heats the surface of the heating roll body, the surface temp. is uniform, and the rate of occurrence of fixing defect is reduced considerably.