Automatic document feeder

Abstract

The invention is an automatic document feeder (ADF) that includes an opening for feeding paper. The automatic document feeder is used for feeding papers from a paper holder through the opening in the feed direction. The automatic document feeder includes at least an inert-wheel holder, an inert wheel, a transmission shaft, a rolling wheel, and a paper-wiping element. The inert-wheel holder is installed at the opening and includes a holding shaft, an inert-wheel trough, and a paper-wiping trough, where the holding shaft is vertical to the feed direction. The inert wheel, which is installed in the inert-wheel trough, is capable of rolling in the direction of the holding shaft, and the inert wheel has an inert-wheel surface projecting off the inert-wheel trough. The transmission shaft is capable of rolling in the direction of the holding shaft. The rolling wheel is installed on the transmission shaft coaxially, and the rolling wheel has a rolling-wheel surface in contact with the inert-wheel surface. The paper-wiping element is installed on the transmission shaft with a position corresponding to the paper-wiping trough.

What is claimed is:  
     
         1 . An automatic document feeder (ADF), comprising an opening for feeding papers, the automatic document feeder feeding papers from a paper holder through the opening in a feed direction, the automatic document feeder comprising at least: 
 an inert-wheel holder, installed at the opening, the inert-wheel holder comprising a holding shaft, an inert-wheel trough, and a paper-wiping trough, wherein the holding shaft is vertical to the feed direction;    an inert wheel, installed in the inert-wheel trough, capable of rolling in the direction of the holding shaft, the inert wheel having an inert-wheel surface projecting off the inert-wheel trough;    a transmission shaft, capable of rolling in the direction of the holding shaft;    a rolling wheel, installed on the transmission shaft coaxially, the rolling wheel having a rolling-wheel surface in contact with the inert-wheel surface; and    a paper-wiping element, installed on the transmission shaft with a position corresponding to the paper-wiping trough;    wherein the transmission shaft drives the rolling wheel and causes the paper-wiping element to roll; the rolling wheel, as driven, applies a first force to the inert wheel to roll in an opposite direction of the rolling wheel, thereby feeding papers into the opening between the rolling wheel and the inert wheel in the feed direction, and the paper-wiping element, as driven, applies a second force to the feed paper, which is parallel to the feed direction.    
     
     
         2 . The automatic document feeder according to  claim 1 , wherein the paper holder is a flatbed of a scanner.  
     
     
         3 . The automatic document feeder according to  claim 1 , wherein the paper-wiping element is made of a flexible film.  
     
     
         4 . The automatic document feeder according to  claim 3 , wherein the film is mylar.  
     
     
         5 . The automatic document feeder according to  claim 4 , wherein the paper holder is a flatbed of a scanner.  
     
     
         6 . A scanner, comprising an automatic document feeder, the automatic document feeder comprising an opening for feeding papers, the automatic document feeder feeding papers from a paper holder through an opening in a feed direction, the scanner comprising at least: 
 an inert-wheel holder, installed at the opening, the inert-wheel holder comprising a holding shaft, an inert-wheel trough, and a paper-wiping trough, wherein the holding shaft is vertical to the feed direction;    an inert wheel, installed in the inert-wheel trough, capable of rolling in the direction of the holding shaft, the inert wheel having an inert-wheel surface projecting off the inert-wheel trough;    a transmission shaft, capable of rolling in the direction of the holding shaft;    a rolling wheel, installed on the transmission shaft coaxially, the rolling wheel having a rolling-wheel surface in contact with the inert-wheel surface; and    a paper-wiping element, installed on the transmission shaft with a position corresponding to the paper-wiping trough;    wherein the transmission shaft drives the rolling wheel and causes the paper-wiping element to roll; the rolling wheel, as driven, applies a first force on the inert wheel to roll in an opposite direction of the rolling wheel, thereby feeding the feed papers into the opening between the rolling wheel and the inert wheel in the feed direction; and the paper-wiping element, as driven, applies a second force to the feed paper, which is parallel to the feed direction.    
     
     
         7 . The automatic document feeder according to  claim 6 , wherein the paper-wiping element is made of a flexible film.  
     
     
         8 . The automatic document feeder according to  claim 7 , wherein the film is mylar.