Canon has developed a dual heater technology for controlling the temperature rise at non-paper regions for the on-demand fixing (ODF) system and has applied the technology to numerous laser-beam printer models. For the fuser heater, this technology uses a dual heater with two types of heating elements that differ in their lengthwise heat distribution. Further, the power applied to each of the two types of heating elements is varied according to the width of the paper to be printed on in order to control the heater's lengthwise heat distribution and thereby suppress the temperature rise at non-paper regions. In this study, the effect of the dual heater technology in suppressing the temperature rise at non-paper regions was estimated through comparison with the conventional ODF heater by using three dimensional heat transfer simulation. The temperature rise at non-paper regions in a prototype dual heater was found to be a close match to the estimation obtained through simulation, showing that the prototype operated as expected.