Sheet feeding apparatus and image forming apparatus

Abstract

A sheet feeding apparatus including: a separating roller which abuts against a feed roller and is rotated in association with the feed roller; and a torque-limiter for allowing the separating roller to rotate in association with the feed roller when a rotation torque larger than a predetermined torque is acted on the separating roller and for preventing the separating roller from rotating in association with the feed roller when the rotation torque equal to or smaller than the predetermined torque is acted on the separating roller, in which sheets fed from a sheet feed cassette are separated one by one by the feed roller and the separating roller, the separating roller urged against the feed roller is supported by a guide member in a slidable manner, and the separating roller is guided with a predetermined angle in a direction different from a direction in which the feed roller is opposed to the separating roller.

1 . A sheet feeding apparatus comprising: 
 a sheet stacking member configure to support sheets;    a sheet feeding member configure to feed the sheet from said sheet stacking member;    a sheet separating portion including a separating roller provided so as to abut against said sheet feeding member and a torque-limiter for allowing said separating roller to rotate in association with said sheet feeding member when a rotation torque larger than a predetermined torque is acted on said separating roller and for preventing said separating roller from rotating in association with said sheet feeding member when the rotation torque equal to or smaller than the predetermined torque is acted on said separating roller;    a guide member configure to support said sheet separating portion in a slidable manner and guiding said sheet separating portion with a predetermined angle in a direction different from a direction along which said sheet feeding member is opposed to said separating roller; and    an urging member configure to urge said sheet separating portion so that said separating roller is in pressure contact with said sheet feeding member.    
   
   
       2 . A sheet feeding apparatus according to  claim 1 , wherein said sheet separating portion further comprising a supporting member for integrally supporting said separating roller and said torque-limiter, and said supporting member is supported by said guiding member in a slidable manner and is urged against said sheet feeding member by said urging member.  
   
   
       3 . A sheet feeding apparatus according to  claim 1 , wherein an angle formed by the direction along which said sheet feeding member is opposed to said separating roller and a direction along which said sheet separating portion slides is equal to or lower than  
     
       
         
           
             
               tan 
               
                 - 
                 1 
               
             
             ⁡ 
             
               ( 
               
                 1 
                 
                   μ 
                   ⁢ 
                   s 
                 
               
               ) 
             
           
         
       
     
     where a coefficient of friction between sheets is given as μs.  
   
   
       4 . A sheet feeding apparatus according to  claim 1 , wherein said guide member comprises a flat guide surface, and said supporting member is supported so that said supporting member is slide-able along said guide surface.  
   
   
       5 . A sheet feeding apparatus according to  claim 4 , wherein said supporting member comprises a rib, and said supporting member slides while bringing said rib into contact with said guide surface.  
   
   
       6 . A sheet feeding apparatus according to  claim 4 , wherein said supporting member comprises a rotatable roller, and said supporting member slides along said guide surface while rotating said roller.  
   
   
       7 . A sheet feeding apparatus according to  claim 1 , wherein said guide member comprises a rib, and said supporting member slides while being in contact with said rib.  
   
   
       8 . A sheet feeding apparatus according to  claim 1 , wherein said guide member comprises a rotatable roller, and said supporting member slides while rotating said roller.  
   
   
       9 . An image forming apparatus, comprising: 
 a sheet feeding apparatus as recited in claims  1 ; and    an image forming portion for forming an image on a sheet fed from said sheet feeding apparatus.