Patent ID: 7441763
Filing Date: 2008-10-28
Classification: B65H

Abstract:
1. An automatic document feeder for separating preloaded sheets of paper and transferring them to another side, comprising: a paper-picking roller, which rotates to move one of the sheets of paper; a paper-separating roller, which is coupled via a gear set with the paper-picking roller to rotate the paper-picking roller and receives the sheet of paper transferred from the paper-picking roller; a damping element, which is in constant contact at a contact position with the paper-separating roller, the contact position being the position for the paper-separating roller to receive the sheet of paper; a driving shaft, which provides a rotating force; a clutch, which comprises a first clutch element fixed on the driving shaft and a second clutch element fixed on the paper-separating roller, wherein the driving shaft rotates the paper-separating roller when the clutch is closed and does not rotate the paper-separating roller when the clutch is separate, wherein the first clutch element comprises a first tooth that projects in a radial direction from a surface of the driving shaft, and the second clutch element comprises a second tooth that projects in an axial direction from an end of the paper-separating roller, and wherein when the first tooth abuts against the second tooth, the clutch is closed, and when the first tooth is separated from the second tooth, the clutch is separate; and a paper-feeding roller, which receives and transfers the sheet of paper transferred from the paper-separating roller; wherein when the clutch is closed, a linear speed of the paper-feeding roller is larger than that of the paper-separating roller, and when the sheet of paper is transferred simultaneously by the paper-separating roller and the paper-feeding roller, the clutch is separate so that the paper-feeding roller and the paper-separating roller have the same linear speed.