Patent ID: 8113500
Filing Date: 2012-02-14
Classification: B65H,H04N

Abstract:
1. A duplex automatic document feeder adapted for use in an image-formation device, the image-formation device having a scanning module for scanning a document, said duplex automatic document feeder comprising: a feeding tray adapted for feeding the document; a first path adapted to extend from said feeding tray to the scanning module so as to invert the document when the document is moved along said first path; a separation roller adapted for moving the document from said feeding tray onto said first path; an ejecting tray; a first reversing roller unit disposed in proximity to said ejecting tray and adapted for allowing the document to move in a direction onto said ejecting tray and in an opposite direction to reverse the document; a second path adapted to extend from the scanning module to said first reversing roller unit and adapted for guiding movement of the document just after a first scanning operation is performed on the document; a third path in spatial communication with said first and second paths and adapted for guiding movement of the reversed document from said first reversing roller unit onto an intermediate portion of said first path; a second reversing roller unit disposed in proximity to said first reversing roller unit and adapted for reversing the document; a fourth path in spatial communication with said second path and said second reversing roller unit and adapted for guiding movement of the document just after a second scanning operation is performed on the document; a housing unit; an ejecting path adapted for guiding movement of the document from said second reversing roller unit onto an intermediate portion of said second path; and a first guide unit adapted to be controlled to guide movement of the document along a selected one of said second and fourth paths; wherein said first guide unit includes a switching gate disposed pivotally in said housing unit at a junction between said second and fourth paths, said switching gate being pivotable between a first position whereat said switching gate closes said fourth path to limit movement of the document into said first reversing roller unit via said second path, and a second position whereat said switching gate closes said second path to limit movement of the document into said second reversing roller unit via said fourth path; wherein said ejecting path is in spatial communication with said junction between said second and fourth paths, said switching gate being configured as a curved rod having a curved guiding surface, said switching gate being further pivotable to a third position, wherein, when said switching gate is disposed in said first position, said curved guiding surface guides the document to move from said second path into said first reversing roller unit; when said switching gate is disposed in said second position, said curved guiding surface guides the document to move from said second path into said second reversing roller unit via said fourth path; and when said switching gate is disposed in said third position, said curved guiding surface guides the document to move from said ejecting path into said first reversing roller unit; and wherein said first guide unit further includes: a rotary disk disposed pivotally in said housing unit and having an outer periphery formed with first, second, and third positioning notches, said switching gate being connected fixedly to said rotary disk, and a solenoid valve including an engaging member biased to move into said first positioning notch when said switching gate is disposed in said first position, into said second positioning notch when said switching gate is disposed in said second position, and into said third positioning notch when said switching gate is disposed in said third position, said solenoid valve being activated so as to remove said engaging member from said switching gate just before said switching gate is rotated in said housing unit.