Underlapping sheet feeders

Abstract

A sheet feeder comprises a roller configured to rotate about an axis and an input drive configured to deliver single sheets to the roller such that a leading edge of each sheet is substantially parallel to the axis. The roller comprises a plurality of flexible fins extending along the axis. As the roller rotates, one of the sheets can be lifted by the rotating fins to pass over the roller, while the leading edge of a following sheet is delivered to the roller in an underlapping relationship with the first sheet.

1 .- 12 . (canceled) 
     
     
         13 . A sheet feeder comprising:
 a roller configured to rotate about an axis; and   an input drive configured to deliver single sheets to the roller along a direction substantially perpendicular to the axis;   wherein the roller comprises a plurality of flexible fins extending along the axis, whereby as the roller rotates a first one of the sheets can be lifted by the fins to pass over the roller and a leading edge of a second one of the sheets can be delivered to the roller in an underlapping relationship with the first sheet.   
     
     
         14 . A sheet feeder according to  claim 13 , comprising at least three fins disposed about the circumference of the roller. 
     
     
         15 . A sheet feeder according to  claim 13 , comprising up to ten fins disposed about the circumference of the roller. 
     
     
         16 . A sheet feeder according to  claim 13 , wherein the input drive delivers the sheets along the surface of a platen, an edge of the platen being positioned to come into contact with the fins during rotation of the roller. 
     
     
         17 . A sheet feeder according to  claim 13 , further comprising an output drive configured to withdraw sheets from the roller. 
     
     
         18 . A sheet feeder according to  claim 13 , further comprising a gate for controlling the withdrawal of sheets from the roller. 
     
     
         19 . A method of feeding sheets in an underlapping series, comprising:
 delivering a series of single sheets to a roller, the roller comprising a plurality of flexible fins extending along an axis of the roller and the sheets being delivered along a direction substantially perpendicular to the axis;   rotating the roller so that the fins lift a first one of the sheets to pass over the roller;   delivering a second one of the sheets to the roller while the first sheet remains above the roller; and   rotating the roller so that the fins lift the second sheet to pass over the roller in an underlapping relationship with the first sheet.   
     
     
         20 . A method according to  claim 19 , comprising rotating the roller continuously. 
     
     
         21 . A method according to  claim 20 , comprising rotating the roller at a rate such that a surface speed of the roller is faster than a delivery speed of the sheets. 
     
     
         22 . A method according to  claim 19 , comprising using a gate downstream from the roller to maintain the first sheet above the roller while the second sheet is delivered to the roller. 
     
     
         23 . A method according to  claim 19 , comprising operating an output drive to withdraw the sheets from the roller. 
     
     
         24 . A method according to  claim 19 , further comprising aligning the sheets such that they are delivered to the roller with a leading edge of each sheet substantially parallel to the axis.