An image forming apparatus, such as a laser printer, may use high levels of heat to form images, and some elements may expand and contract with changing temperatures. An apparatus may include a heat roller disposed against a pressure roller, with an endless belt member enclosing the pressure roller. The belt member may also have different frictional characteristics on an inside and outside of the roller, such that when peripheral speeds change due to expansion of the pressure roller, the belt member may be configured to slip against the pressure roller, and maintain a frictional relationship with the heat roller (or a printing medium, such as paper, that is pinched between the rollers). Additionally, the rotational speed of an axis of the pressure roller may be adjusted to compensate for the thermal expansion.