Patent ID: 7215447

Claim:
A method of optimal focusing for a document scanner, wherein the scanner comprises an optical module movable to perform a scanning operation over an area of a document under control of a control unit, the method comprising the steps of: (a) moving the optical module in a first direction substantially parallel to the document to a starting scan line of the document; (b) moving the optical module in a second direction substantially perpendicular to the document for adjusting a focus position of the optical module with respect to the document in accordance with a best focus value corresponding to the selected scan line; (c) temporarily suspending the optical module for a predetermined time period until a vibration of the optical module is damped out; (d) scanning the selected scan line of the document; and (e) moving the optical module to a next one of the scan lines of the document in the first direction and repeating steps (b) to (d) until all scan lines are done.