Contact heat fusing apparatus

Claim 1

A contact fusing apparatus for fusing a toner image carried on a support, comprising a fuser roller having an elastically deformable surface and having associated heating means for heating such roller to a temperature sufficient to cause fusion of toner, an opposed pressure roller forming with said fuser roller a bite through which a support carrying a toner image can pass, means for transmitting a driving torque to at least one of such rollers, clamping means operative to apply a clamping force to at least one of such rollers to maintain the two rollers in an operative position with a clamping pressure in the bite thereof sufficient to cause elastic deformation of said roller surface, separate frame means each having two opposite sides for supporting the opposite ends of said fuser and pressure rollers respectively and means mounting one of said frame means for differential relative limited free bodily movement of its opposite sides, and of the roller ends supported thereby, away from and towards the corresponding sides of the other frame while the rollers are maintained in said operative position, the axis of the roller supported by said movably mounted frame means remaining during its movement generally within a plane perpendicular to a tangent through said bite, whereby the separation between said roller axes while the rollers are in said operative position can vary nonuniformly along the length of said bite in response to instantaneous variations in the thickness of the toner image across the support.