Patent ID: 7599582

Claim:
A scanning mechanism for moving a mobile optical device between a first end and a second end along a main scanning direction that comprises: means for maintaining substantially the same total bend length and radius as the mobile optical device moves along the main scanning direction; means for maintaining substantially the same tension on a cable as the mobile optical device moves along the main scanning direction, wherein the optical device is operatively connected to the cable; means for driving the mobile optical device along the main scanning direction; a first stationary turning pulley that is positioned adjacent the first end of the main scanning direction; a second stationary turning pulley that is positioned adjacent the second end of the main scanning direction; a cable that is partially wound around the first and second stationary pulleys, wherein the cable has a first end that is secured and a second end that is secured and the mobile optical device that positioned between the first and second stationary turning pulleys, wherein the means for maintaining substantially the same tension, same total bend length and radius on the cable comprises: (a) a first compensating pulley; and (b) a second compensating pulley, wherein the cable that is partially wound around the first and second compensating pulleys, wherein the first and second compensating pulleys are linked to move in unison along a path that is between the first and second stationary turning pulleys, and wherein the first compensating pulley is closer to the first stationary turning pulley than is the second compensating pulley and wherein the means for driving the mobile optical device moves the mobile optical device in a first direction and simultaneously moves the linked first and second compensating pulleys in a second direction that is opposite to the first direction.