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 . additionally , the rotational speed of an axis of the pressure roller may be adjusted to compensate for the thermal expansion .