Scanner drive system having minimum rotational error carriage suspension

摘要

The scanner includes a transmissive object focal plane which is positioned parallel to and at a vertical distance below a reflective object focal plane. A device allows selection between the focal planes. An original document is positioned in the selected object focal plane so as to be stationary w.r.t. to the scanner during scanning. A scan carriage can be moved linearly along a scanning axis. An illumination source is positioned between the focal planes to illuminate a scan line of the original document positioned in the selected focal plane. The scan carriage also includes an optical imaging and sensor device positioned below the transmissive object focal plane to obtain a digitised representation of the scan line. The scan carriage moves along the scanning axis to obtain digitised representations of successive scan lines of the original document and together with the digitised representations of the successive scan lines form a digital representation of the original document. The scanning carriage is suspended along an axis of rotation parallel to, and coincident with, the scan line.