PURPOSE: To uniformize the temp. distribution of a heat roll and to prevent the exfoliation of a heating resistor layer, etc., by providing a low expansion layer made of iron or iron alloy between the outside periphery of a cylindrical base body and insulating layer.
CONSTITUTION: The low expansion layer 2 made of the iron or iron alloy is provided on the outside periphery of the cylindrical base body 1 and further, the insulating layer 3, the heating resistor layer 4 made of ceramics and a protective layer 5 consisting of fluoroplastic, etc., are successively provided on the outside periphery thereof, by which the heat roll is formed. The heat roll is heated when electric power is supplied through electrodes 6 provided at both ends of the heating resistor layer 4. Since the cylindrical base body 1 is made of an aluminum or copper alloy and has good heat conductivity, the heat distribution of the heat roll can be uniformized. However, this cylindrical base body 1 has a large coefft. of thermal expansion and, therefore, the thermal expansion is limited by the low expansion layer 2 and the exfoliation of the heating resistor layer 4 of the outside peripheral insulating layer 3 is prevented.
KASAGOE TOSHIYUKI
IIMURA TSUTOMU
