JPS57146280A - Fixing roller for electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To reduce the quantity of heat carried away by a copy paper and the quantity of heat radiated to the air, by forming the surface part of a roller, which is brought into contact with a toner image, with a thin layer such as a metallic layer and forming a heat insulating layer, where a power source is arranged internally, under this thin layer. CONSTITUTION:A heater H is provided as a heat source in the center of a fixing roller 4, and the heater H is covered with a core bar 5. The outside of the core bar 5 is covered with a heat insulating layer 6 such as Teflon rubber, and the outside of the heat insulating layer 6 is covered with a metallic thin layer 7 or a thin layer consisting of a substance which has a heat capacity approximately equal to that of a metal. The surface of a pressure roller 8 facing to the roller 4 is covered with a heat insulating rubber layer 9. Thus, the temperature of the face brought into contact with the roller 4 is high in the initial nipping stage of a copy form S at a fixing time, and fixing is performed sufficiently. In the final nipping stage, the temperature of this face is lowered because the heat capacity of the thin film 7 due to the metal is small, and the heat transfer loss is reduced by components corresponding to this lowering of the temperature.