Sheet feeding apparatus and image forming apparatus

Abstract

A sheet feeding apparatus includes a stacking portion, a rotary feeding member configured to feed the sheet in a sheet feeding direction, a first separation portion including a separation surface, the detachable unit including a second separation portion. A direction that intersects both the sheet feeding direction and a rotation-axis direction of the rotary feeding member, and that extends from the separation surface toward the rotary feeding member is defined as a projection direction. The second separation portion is positioned downstream of the separation surface in the projection direction in a state where the detachable unit is attached to the first separation portion. Another portion of the detachable unit other than the second separation portion is positioned upstream of the separation surface in the projection direction in a state where the detachable unit is attached to the first separation portion.

What is claimed is: 
     
         1 . A sheet feeding apparatus comprising: 
  a stacking portion on which a sheet is stacked;    a rotary feeding member configured to feed the sheet stacked on the stacking portion, toward an image forming portion in a sheet feeding direction;    a first separation portion including a separation surface disposed so as to contact the sheet fed by the rotary feeding member; and    a detachable unit detachably attached to the first separation portion, the detachable unit including a second separation portion that contacts a sheet fed by the rotary feeding member so as to separate the sheet, together with the separation surface, one by one,    wherein a direction that intersects both the sheet feeding direction and a rotation-axis direction of the rotary feeding member, and that extends from the separation surface toward the rotary feeding member is defined as a projection direction,    the second separation portion is positioned downstream of the separation surface in the projection direction in a state where the detachable unit is attached to the first separation portion, and    another portion of the detachable unit other than the second separation portion is positioned upstream of the separation surface in the projection direction in a state where the detachable unit is attached to the first separation portion.   
     
     
         2 . The sheet feeding apparatus according to  claim 1 , wherein the first separation portion includes an opening portion into which the detachable unit to be attached to the first separation portion is inserted. 
     
     
         3 . The sheet feeding apparatus according to  claim 2 , wherein the opening portion is opened toward a downstream side in the projection direction. 
     
     
         4 . The sheet feeding apparatus according to  claim 2 , wherein the opening portion is opened toward an upstream side in the projection direction. 
     
     
         5 . The sheet feeding apparatus according to  claim 2 , wherein the opening portion is opened in a vertical direction. 
     
     
         6 . The sheet feeding apparatus according to  claim 2 , wherein the detachable unit includes a first end and a second end in the rotation-axis direction, 
        the second separation portion includes: 
  a first sheet-separation portion disposed at a position closer to the first end than to the second end in the rotation-axis direction; and 
  a second sheet-separation portion disposed at a position closer to the second end than to the first end in the rotation-axis direction, and 
  a width of the opening portion is longer than a distance between the first sheet-separation portion and the second sheet-separation portion in the rotation-axis direction. 
 
     
     
         7 . The sheet feeding apparatus according to  claim 2 , further comprising a restricting member configured to restrict the detachable unit, inserted in the opening portion, from being detached from the first separation portion. 
     
     
         8 . The sheet feeding apparatus according to  claim 7 , wherein the restricting member is configured to move between a restricting position and an allowable position, the restricting position being a position at which the restricting member restricts the detachable unit from being detached from the first separation portion, the allowable position being a position at which the restricting member allows the detachable unit to be detached from the first separation portion. 
     
     
         9 . The sheet feeding apparatus according to  claim 8 , wherein the restricting member covers a part of the opening portion at the restricting position, and increases an opening area of the opening portion by moving from the restricting position to the allowable position. 
     
     
         10 . The sheet feeding apparatus according to  claim 7 , wherein the restricting member is configured to be detachably fixed to the first separation portion. 
     
     
         11 . The sheet feeding apparatus according to  claim 2 , wherein the first separation portion includes an abutment portion, 
        the detachable unit includes an abutted portion configured to abut against the abutment portion, and 
        the sheet feeding apparatus further includes an urging member configured to position the detachable unit with respect to the first separation portion by urging the detachable unit such that the abutted portion abuts against the abutment portion in a state where the detachable unit is attached to the first separation portion. 
     
     
         12 . The sheet feeding apparatus according to  claim 11 , wherein the urging member is configured to urge the detachable unit in the projection direction in a state where the detachable unit is attached to the first separation portion, and 
        the abutted portion is positioned upstream of the abutment portion in the projection direction in a state where the detachable unit is attached to the first separation portion. 
     
     
         13 . The sheet feeding apparatus according to  claim 11 , wherein the detachable unit is configured to move upstream in the projection direction against an urging force of the urging member while the second separation portion is pushed by a sheet fed by the rotary feeding member. 
     
     
         14 . The sheet feeding apparatus according to  claim 11 , wherein the abutted portion is configured to restrict the detachable unit from being detached from the first separation portion by being locked by the abutment portion in a state where the detachable unit is inserted in the opening portion. 
     
     
         15 . The sheet feeding apparatus according to  claim 2 , further comprising a cover configured to open and close the opening portion. 
     
     
         16 . The sheet feeding apparatus according to  claim 15 , wherein the opening portion is a first opening portion, 
        the cover includes a second opening portion, and 
        the second separation portion projects from the second opening portion in the projection direction when the cover is closed after the detachable unit is inserted into the first opening portion. 
     
     
         17 . The sheet feeding apparatus according to  claim 1 , wherein at least a portion of the second separation portion has a coefficient of friction higher than that of the separation surface. 
     
     
         18 . An image forming apparatus comprising: 
  the sheet feeding apparatus according to  claim 1 ; and    the image forming portion configured to form an image on a sheet fed from the sheet feeding apparatus.   
     
     
         19 . A sheet feeding apparatus comprising: 
  a stacking portion on which a sheet is stacked;    a rotary feeding member configured to feed the sheet stacked on the stacking portion, toward an image forming portion in a sheet feeding direction;    a first separation portion including a separation surface disposed so as to contact the sheet fed by the rotary feeding member; and    a detachable unit detachably attached to the first separation portion, the detachable unit including a second separation portion that contacts a sheet fed by the rotary feeding member so as to separate the sheet, together with the separation surface, one by one,    wherein a direction that intersects both the sheet feeding direction and a rotation-axis direction of the rotary feeding member, and that extends from the separation surface toward the rotary feeding member is defined as a projection direction,    the second separation portion is positioned downstream of the separation surface in the projection direction in a state where the detachable unit is attached to the first separation portion, and    another portion of the detachable unit other than the second separation portion is configured not to contact the sheet fed by the rotary feeding member in a state where the detachable unit is attached to the first separation portion.   
     
     
         20 . An image forming apparatus comprising: 
  the sheet feeding apparatus according to  claim 19 ; and    the image forming portion configured to form an image on a sheet fed from the sheet feeding apparatus.