Automatic document feeding apparatus

Abstract

An automatic document feeding apparatus includes a shaft, an ADF roller for feeding documents piece by piece by cooperating with a separating member, and a power switching member for selectively connecting a driving member with the shaft. The power switching member is installed on the shaft. The ADF roller is also mounted on the shaft such that the ADF roller can rotate by receiving a torque only in a first direction.

1 . An automatic document feeding apparatus comprising: 
 a shaft;    an ADF roller which feeds documents sheet by sheet by cooperating with separating means, the ADF roller being mounted on the shaft such that the ADF roller can rotate by receiving a torque only in a first direction from the shaft;    power switching means which selectively connects driving means with the shaft, the power switching means being installed on the shaft; and    power coupling means comprising a first coupling portion that slides axially on the shaft to selectively couple the shaft to the ADF roller.    
     
     
         2 . The automatic document feeding apparatus of  claim 1 , wherein the power coupling means further comprises opposing saw tooth shape members.  
     
     
         3 . The automatic document feeding apparatus of  claim 2 , wherein the power coupling means further comprises a spiral concave portion in which a lever is inserted, the lever and spiral concave portions cooperating to slide said first coupling portion to selectively couple the shaft to the ADF roller.  
     
     
         4 . An automatic document feeding apparatus comprising: 
 a shaft;    a pickup roller rotated by receiving a torque from the shaft and picking up a sheet of a document on a feeding base;    a second shaft on which the pickup roller is installed;    an ADF roller to feed the document picked up by the pickup roller;    a separating member engaged with the ADF roller to separate the document sheets individually; and    a bracket on which the pickup roller and ADF roller are installed, and wherein the pickup roller rotates by selectively receiving the torque only in a first direction from the shaft.    
     
     
         5 . The automatic document feeding apparatus of  claim 4 , wherein the ADF roller rotates by selectively receiving a torque only in a first direction from the shaft.  
     
     
         6 . The automatic document feeding apparatus of  claim 4 , further comprising: 
 a first power coupling portion rotated by the torque;    a second power coupling portion installed on at least one of the ADF roller and the pickup roller, the second power coupling portion connected to the first power coupling portion; and    wherein one of the first power coupling portion and the second power coupling portion slides to engage/separate with/from each other.    
     
     
         7 . The automatic document feeding apparatus of  claim 6 , wherein each of the first power coupling portion and the second power coupling portion comprises a saw tooth defined by opposing sections and incline sections to selectively connect with each other when the shaft rotates in the first direction.  
     
     
         8 . The automatic document feeding apparatus of  claim 4 , wherein when the shaft rotates in the first direction, the torque of the shaft is transferred to the bracket and when the shaft rotates in a second direction, the torque of the shaft is not transferred to the bracket.  
     
     
         9 . The automatic document feeding apparatus of  claim 8 , wherein the bracket is rotatable with respect to the shaft.  
     
     
         10 . The automatic document feeding apparatus of  claim 9 , further comprising an elastic member which biases the bracket to rotate in the second direction.