Patent ID: 8112024

Claim:
A heat fixing apparatus for heating and fixing a toner image formed on a recording material onto the recording material, comprising: an endless belt; a heater that contacts an internal surface of the endless belt, the heater having a first heat generation member, and a second heat generation member whose ratio of the resistance value per a unit length at edge portions of the heater to the resistance value per the unit length at a center portion of the heater in a longitudinal direction is larger than the ratio of the resistance value per the unit length at edge portions of the heater to the resistance value per the unit length at a center portion of the heater in a longitudinal direction of the first heat generation member; a back-up member configured to form a fixing nip portion that pinches and conveys a recording material through the endless belt together with the heater; and a pressure change mechanism capable of setting the pressure applied to the fixing nip portion to a first pressure and a second pressure lower than the first pressure; wherein the apparatus has a first fixing process mode for performing a first fixing process under the first pressure and a second fixing process mode for performing a second fixing process under the second pressure; and wherein when the second fixing process is performed in the second fixing process mode, a heat proportion of the second heat generation member is set to be smaller than a heat proportion of the first heat generation member independently of the size of the recording material.