Patent ID: 7605953

Claim:
A method to compensate for imperfect scanner motion in a scanning apparatus having a moveable scanner, comprising: generating an error array by measuring errors in a scanner position at each of a plurality of spaced positions along a direction of travel of said scanner; generating an error compensation array from said error array based on a low frequency component of said error array; interpolating data contained in said error compensation array to provide continuous error correction of said scanner along a scanning range of said scanner, wherein a scan motor is coupled to said scanner via a drive train, said low frequency error component being associated with errors in said scan position occurring within about one revolution of gear in said drive train, and wherein said drive train includes a toothed drive belt which engages a toothed pulley associated with said scanner, said scanning apparatus including a belt guard to prevent said toothed pulley from jumping teeth with respect to said toothed drive belt.