Slidable Sheet Separator for an Image Forming Device

Abstract

A sheet separator and apparatus utilizing the same for separating media sheets in an image forming device. The apparatus includes a supporting member for supporting a stack of media sheets, a pick assembly to pick media sheets and to feed the media sheets to a processing assembly of the image forming device, and a media dam having at least one sheet separator. Each sheet separator includes a casing inclined at a predetermined angle to the supporting member, a biasing member and a base member slidable within the casing. A plurality of detents in the form of steps or teeth are provided on a sheet receiving surface of the base member and the biasing member act to separate a top most media sheet from an adjacent media sheet to prevent double feeding of media sheets.

1 . An apparatus for separating media sheets in an image forming device, the apparatus comprising:
 a supporting member for supporting a stack of media sheets;   a pick assembly disposed upon the stack of media sheets for picking media sheets from the stack of media sheets and feeding the media sheets into a feed path to a processing assembly of the image forming device; and   a media dam positioned at a predetermined angle with respect to the supporting member, the media dam positioned adjacent to both the leading edges of the media sheets in the stack and to the pick assembly, the media dam having at least one slidable sheet separator, the at least one slidable sheet separator comprising:
 a casing; 
 a biasing member for applying a biasing force at the predetermined angle to the base member; 
 a base member positioned within the casing by the biasing member at an initial position with respect to the stack of media sheets, the base member slidable within the casing from a resultant force applied by one of the biasing member and one or more media sheets fed from the stack of media sheet by the pick assembly; and 
 a plurality of detents in the form of steps on a sheet-receiving surface of the base member, at least one of the plurality of detents engaging and separating a topmost media sheet from an adjacent fed media sheet when picked by the pick assembly allowing the topmost media sheet to be fed into the feed path to the processing assembly while resisting movement of the adjacent fed media sheet into the feed path. 
   
     
     
         2 . The apparatus of  claim 1 , wherein each of the at least one sheet separator is detachably attached to the media dam. 
     
     
         3 . The apparatus of  claim 1 , wherein the casing of the at least one sheet separator is molded within the media dam. 
     
     
         4 . The apparatus of  claim 1 , wherein the biasing member comprises a compression spring for returning the base member to the initial position after the top most media sheet is separated from the adjacent media sheet. 
     
     
         5 . The apparatus of  claim 1 , wherein a riser of each detent of the plurality of detents is oriented vertically relative to a respective leading edge of each fed media sheet when each fed media sheet arrives at the at least one sheet separator. 
     
     
         6 . The apparatus of  claim 1 , wherein the base member facilitates bubble formation at respective leading edges of the top most media sheet and the adjacent media sheet when the top most media sheet and the adjacent media sheet arrive at the base member. 
     
     
         7 . The sheet separator of  claim 1 , wherein each riser of each detent of the plurality of detents has a height that is greater than the thickness of the media sheet being fed. 
     
     
         8 . The apparatus of  claim 7 , wherein each riser of each detent of the plurality of detents has a height of about 0.5 mm. 
     
     
         9 . The apparatus of  claim 1 , wherein a tread of each detent of the plurality of detents has a depth of about 0.3 mm. 
     
     
         10 . The apparatus of  claim 1 , wherein an interior angle a between the riser and the tread of each detent produces a minimum resisting force by the base member on the adjacent media sheet that is always higher than a driving force by the pick assembly applied to the adjacent media sheet. 
     
     
         11 . The apparatus of  claim 10 , wherein the interior angle α is in the range of 50 degrees to 70 degrees. 
     
     
         12 . The apparatus of  claim 1 , wherein the height of the base member of the at least one sheet separator is longer than a height of stack of media sheets. 
     
     
         13 . The apparatus of  claim 1 , wherein the base member and the plurality of detents of the each sheet separator are composed of glass bead filled polyoxymethylene. 
     
     
         14 . A sheet separator for a media dam for separating media sheets being fed by a pick assembly from a stack of media sheets into the media dam and then to a processing assembly in an image forming device, the sheet separator comprising:
 a casing inclinable at a predetermined angle with respect to the leading edges of the media sheets in the stack;   a base member slidably received in the casing and positioned at an initial position with respect to the leading edges of the media sheets of the stack, the base member having a plurality of stepped detents forming a sheet receiving surface on the base member; and   a biasing spring for applying a biasing force at the predetermined angle to the base member at the initial position;   the base member being slidable upwards at the predetermined angle within the casing by a driving force applied by the fed media sheet, at least one of the plurality of stepped detents being struck by and engaging a leading edge of a top most fed media sheet and when present a leading edge of an adjacent fed media sheet, the struck at least one detent and the biasing spring facilitating the separation of the top most fed media sheet from the adjacent fed media sheet for feeding to the processing assembly with the biasing spring returning the base member to the initial position after the leading edge of top most fed media disengages with the struck at least one detent.   
     
     
         15 . A sheet separator in a media dam for separating media sheets being fed from a stack of media sheets to a processing assembly in an image forming device, the sheet separator comprising:
 a base member positionable with the media dam and inclinable at a predetermined angle with respect to the stack of media sheets;   a biasing member for applying a biasing force to the base member at the predetermined angle to place the base member in a first position when positioned with the media dam; and   a plurality of detents in the form of steps on a sheet-receiving surface of the base member, for engaging a leading edge of a fed media sheet.   
     
     
         16 . The sheet separator of  claim 15 , wherein a riser of each detent of the plurality of detents is oriented vertically relative to a respective leading edge of each fed media sheet when each fed media sheet arrives at the at least one sheet separator. 
     
     
         17 . The sheet separator of  claim 16 , wherein the plurality of detents of the base member facilitate bubble formation at respective leading edges of the top most media sheet and the adjacent media sheet when the top most media sheet and the adjacent media sheet arrive at the base member. 
     
     
         18 . The sheet separator of  claim 15 , wherein each riser of each detent of the plurality of detents has a height that is greater than the thickness of the media sheet being fed. 
     
     
         19 . The sheet separator of  claim 18 , wherein each riser of each detent of the plurality of detents has a height of about 0.5 mm. 
     
     
         20 . The sheet separator of  claim 15 , wherein a tread of each detent of the plurality of detents has a depth of about 0.3 mm. 
     
     
         21 . The sheet separator of  claim 15 , wherein an interior angle α between the riser and the tread of each detent produces a minimum resisting force by the base member on the adjacent media sheet that is always higher than a driving force by the pick assembly applied to the adjacent media sheet. 
     
     
         22 . The sheet separator of  claim 21 , wherein the interior angle α is in the range of 50 degrees to 70 degrees. 
     
     
         23 . The sheet separator of  claim 15 , wherein the height of the base member of the at least one sheet separator is longer than a height of stack of media sheets. 
     
     
         24 . The sheet separator of  claim 15 , wherein the base member and the plurality of detents of the each sheet separator are composed of glass bead filled polyoxymethylene.