Patent ID: 7265880
Filing Date: 2007-09-04
Classification: H04N

Abstract:
1. A system for determining a return of a photo sensor in a scanner with two end positions, comprising: a photo sensor, which scans a document and converts an analog signal obtained from the scanning into a digital signal; a first base position sensing unit, which is installed on one end base position in a scanning region of the scanner; a second base position sensing unit, which is installed on the other end base position in the scanning region of the scanner; a metal component, which is provided under the photo sensor, moves along with the photo sensor, and is charged with positive charges; a line resistance material, which is provided under the metal component for the metal component to slide thereon, the position where the metal component stays being taken as a boundary to divide the line resistance material into two sections; and an electrical current meter, which measures a first current in a first section of resistance between the metal component and the first base position sensing unit and a second current in a second section of resistance between the metal component and the second base position sensing unit; wherein magnitudes of the measured currents are used to determine a position for the photo sensor to return.