Patent ID: 8075128

Claim:
An image transfer mechanism for pressing a print medium against an imaging element, the image transfer mechanism comprising: a pressure element; a lever system for pressing the pressure element toward the imaging element; wherein the lever system has a load attachment point that has a range of positions dependent on the thickness of a print medium positioned between the imaging element and the pressure element; and a load mechanism comprising a load connector having a proximal end and having a distal end attached to the load attachment point of the lever system so that displacement of the attachment point of the lever system causes longitudinal movement of the load connector; wherein the load mechanism applies a load force at the load attachment point of the lever system that is substantially constant throughout the range of positions of the load attachment point; wherein the load mechanism additionally comprises a spring; wherein the load mechanism additionally comprises a crank attached to the spring and to the proximal end of the load connector so that longitudinal movement of the load connector causes a change in the length of the spring and thereby a change in the spring force; and wherein the crank is configured so that the change in the spring force due to longitudinal movement of the load connector produces a lesser change in the load force at the distal end of the load connector than the change in the spring force due to the change in length of the spring.