Scanner base for optical scanners

Claim 1

A scanner base for an optical scanner, comprising: a first end plate having a sliding slot, an upright mounting flange, an upright shaft, a locating post, and two upright female screws; a second end plate having a sliding slot, a mounting flange, and a locating post; a roller connected between the sliding slot on said first end plate and the sliding slot on said second end plate and turned on its own axis; a contact image sensor connected between the upright mounting flange of said first end plate and the upright mounting flange of said second end plate and disposed in parallel to said roller to pick up the image of a document passing through the gap between said contact image sensor and said roller; a first bushing mounted within the sliding slot on said first end plate and coupled to one end of said roller; a second bushing mounted within the sliding slot on said second end plate and coupled to one end of said roller opposite to said first bushing; a first torsional spring mounted around the locating post on said first end plate, having one end fastened to said first end plate and an opposite end fastened to said first bushing to hold said roller in place; a second torsional spring mounted around the locating post on said second end plate, having one end fastened to said second end plate and an opposite end fastened to said second bushing to hold said roller in place; a step motor fixedly mounted on the upright female screws of said first end plate, having an output shaft fixedly mounted with a pinion; a stepped transmission gear mounted around the stepped shaft of said first end plate and turned by said step motor through said pinion; and a drive gear coupled to said first bushing and driven by said stepped transmission gear to turn said roller.