Sheet separation using pressing force

Abstract

A sheet separation device includes a separating member to contact a feed roller and to separate sheet-type media transported between the feed roller and the separating member, the separating member movable to contact the feed roller at a plurality of contact points on the feed roller along the withdrawing direction to apply different pressing forces corresponding to the plurality of contact points.

1 . A sheet separation device comprising:
 a feed roller to transport a sheet-type medium in a withdrawing direction of the sheet-type medium;   a separating member movable to first or second contact points on the feed roller to separate a plurality of sheet-type media transported between the feed roller and the separating member; and   an elastic member to apply an elastic force in a direction to allow the separating member to move to contact the feed roller at the first or second contact points,   wherein the separating member is movable to,
 the first contact point on the feed roller to apply a first pressing force, and 
 the second contact point on the feed roller to apply a second pressing force greater than the first pressing force, the second contact point located at a downstream side of the first contact point in the withdrawing direction. 
   
     
     
         2 . The sheet separation device of  claim 1 , wherein the elastic member includes first and second elastic members,
 the first elastic member to apply a first elastic force in a first direction of the separating member to allow the separating member to contact the feed roller at the first or second contact points; and   the second elastic member to apply a second elastic force in a second direction to cause movement of the separating member to the first contact point from the second contact point.   
     
     
         3 . The sheet separation device of  claim 2 , further comprising:
 a holder to support the separating member and be rotatable; and   a hinge to rotatably support the holder and to be movable by the first elastic force to enable the separating member to move between the first and the second contact points.   
     
     
         4 . The sheet separation device of  claim 3 , wherein
 a second angle formed between a line through the second contact point and a center of the feed roller and a line through the second contact point and the hinge when the separating member is at the second contact point is greater than a first angle formed between a line through the first contact point and the center of the feed roller and a line through the first contact point and the hinge when the separating member is at the first contact point.   
     
     
         5 . The sheet separation device of  claim 3 , further comprising a guide member to
 guide a bottom side of the plurality of sheet-type media transported between the feed roller and the separating member, and   move along with the separating member.   
     
     
         6 . The sheet separation device of  claim 5 , wherein the guide member is coupled to the holder. 
     
     
         7 . The sheet separation device of  claim 3 , wherein the first elastic member applies the first elastic force to the holder so that the holder rotates in a direction to allow the separating member to contact the feed roller at the first or second contact points. 
     
     
         8 . The sheet separation device of  claim 3 , further comprising:
 a link to which the hinge is coupled; and   a rotation shaft to rotatably support the link.   
     
     
         9 . The sheet separation device of  claim 8 , wherein the second elastic member is to apply the second elastic force to the link. 
     
     
         10 . The sheet separation device of  claim 3 , wherein the second elastic member includes an elastic frame to support the hinge. 
     
     
         11 . The sheet separation device of  claim 10 , wherein the elastic frame extends in a length direction of the feed roller. 
     
     
         12 . The sheet separation device of  claim 1 , further comprising a torque limiter,
 wherein the separating member includes a retard roller, and   the torque limiter is to selectively enable, according to a size of a load torque applied to the retard roller, a rotation of the retard roller caused by a rotation of the feed roller.   
     
     
         13 . The sheet separation device of  claim 12 , further comprising a driving member to transfer a torque in a direction opposite to the withdrawing direction. 
     
     
         14 . The sheet separation device of  claim 1 , wherein the separating member includes a retard pad. 
     
     
         15 . A sheet separation device, comprising:
 a feed roller to transport a sheet-type medium in a withdrawing direction of the sheet-type medium; and   a separating member to separate a plurality of sheet-type media transported between the feed roller and the separating member,   the separating member movable to contact the feed roller at a plurality of contact points on the feed roller along the withdrawing direction to apply different pressing forces corresponding to the plurality of contact points.