Sheet separating mechanism of an auto document feeder

Abstract

A sheet separating mechanism of an auto document feeding (ADF) device includes an ADF roller, two separating rollers and one pressing element. The pressing element is disposed between the separating rollers to form an assembly, and the pressing element and the separating rollers contact the ADF roller. A sheet is fed under the cooperation of the assembly and the ADF roller. The separating rollers rotate to provide a friction force for sheet separating. The pressing element presses a surface of the sheet such that the sheet may be smoothly fed without bulginess.

1 . A sheet separating mechanism disposed at a sheet-feeding end of an auto document feeding (ADF) device, the mechanism separating a plurality of sheets from one another and feeding each of the sheets into the ADF device, the mechanism comprising: 
 an ADF roller;    at least two separating rollers disposed at a side of the ADF roller to face the ADF roller, wherein surfaces of the at least two separating rollers contact a surface of the ADF roller; and    a pressing element disposed between the at least two separating rollers, wherein:    the pressing element contacts the ADF roller by gravity; and    when the sheet is fed, the at least two separating rollers and the ADF roller rotate, and the pressing element and the at least two separating rollers press against a surface of the sheet.    
   
   
       2 . The mechanism according to  claim 1 , wherein the pressing element and the at least two separating rollers are not moved synchronously.  
   
   
       3 . The mechanism according to  claim 1 , wherein the pressing element and the at least two separating rollers are moved synchronously.  
   
   
       4 . The mechanism according to  claim 3 , further comprising a shaft passing through the at least two separating rollers and the pressing element, wherein the shaft provides a friction force for moving the pressing element on contact surfaces between the pressing element and the shaft.  
   
   
       5 . The mechanism according to  claim 4 , wherein the friction force is provided by engaging teeth between the pressing element and the shaft.  
   
   
       6 . The mechanism according to  claim 4 , wherein the friction force is provided by contacting rough surfaces between the pressing element and the shaft.  
   
   
       7 . The mechanism according to  claim 4 , wherein each of the contact surfaces between the pressing element and the shaft is made of a material with a large friction coefficient.  
   
   
       8 . The mechanism according to  claim 1 , further comprising a shaft passing through the pressing element and the at least two separating rollers, wherein the pressing element is a pickup roller having an axial through hole, and the through hole has a diameter greater than a diameter of the shaft.  
   
   
       9 . The mechanism according to  claim 1 , further comprising a shaft passing through the pressing element and the at least two separating rollers, wherein the pressing element is a presser having one end movably covering the shaft and the other end pressing against the surface of the ADF roller by gravity.  
   
   
       10 . A sheet separating mechanism disposed at a sheet-feeding end of an auto document feeding (ADF) device, the mechanism separating a plurality of sheets from one another and feeding each of the sheets into the auto document feeder, the mechanism comprising: 
 an ADF roller;    at least two separating rollers disposed at one side of the ADF roller to face the ADF roller, wherein surfaces of the separating rollers contact a surface of the ADF roller;    a pressing element disposed between the at least two separating rollers, wherein:    the pressing element and the at least two separating rollers are moved synchronously, and the pressing element has a soft portion contacting the ADF roller; and    when the sheet is fed, the at least two separating rollers, the pressing element and the ADF roller rotate, and the pressing element and the at least two separating rollers press against a surface of the sheet.    
   
   
       11 . The mechanism according to  claim 10 , further comprising a shaft passing through the pressing element and the at least two separating rollers, wherein the pressing element is a sponge cover fixedly covering the shaft.  
   
   
       12 . The mechanism according to  claim 11 , wherein a surface of the sponge cover serves as the soft portion.  
   
   
       13 . The mechanism according to  claim 10 , further comprising a shaft passing through the pressing element and the separating rollers, wherein the pressing element is an annular brush fixedly covering the shaft, and the annular brush has projecting bristles on a surface of the annular brush.  
   
   
       14 . The mechanism according to  claim 13 , wherein the bristles serve as the soft portion.