Method and apparatus for reducing surface temperature variation of an externally-heated fusing roller

In an electrophotographic machine, a method of reducing variation in the surface temperature of an externally-heated fuser that typically occurs during the beginning of a fusing run, at least one heater associated with and engaging said fuser at a heater engagement level to thereby heat said fuser, said method comprising:

• detecting the beginning of a fusing run;
• applying a modified fusing temperature set-point characteristic to the fuser during the beginning of a fusing run;
• checking the mode of the electrophotographic machine to determine whether the machine remains in a fusing mode of operation;
• and
• ceasing said applying step when the electrophotographic machine is no longer operating in the fusing mode.

A method for controlling the temperature of an externally-heated fusing roller in an electrophotographic machine, said machine having at least one heating roller associated with and heating said fusing roller, by controlling the force with which the heating roller engages the fusing roller, said method comprising:

• sensing the surface temperature of the fusing roller to thereby obtain a sensed surface temperature;
• comparing the sensed surface temperature with a target surface temperature;
• calculating an updated heating roller engagement value dependent at least in part upon said comparing step;
• and
• setting the heating roller engagement level to the updated heating roller engagement value.

An electrophotographic machine, including:

• a fusing roller;
• at least one heating roller associated with and heating said fusing roller;
• and
• means for controlling a fusing temperature of a fusing roller, said means providing for adjustment of an engagement force with which said at least one heating roller engages said fusing roller to thereby control said fusing temperature, said adjustment said engagement force being within predetermined limits.