Sheet Discharge Roller Assembly For An Automatic Document Feeding Apparatus

Abstract

A sheet discharge roller assembly for a sheet feeding apparatus includes an upper cylindrical exit roller mounted on a rotatable drive shaft and a lower cylindrical pinch roller having a wheel attached to one end. The pinch roller has a length that is longer than the length of the exit roller and is moveable into contact with the exit roller so as to form a nip for gripping a print media to be discharged. The wheel has a diameter that is larger than that of the pinch roller and an outer circumferential edge composed of a plurality of protruding contact portions arranged in a radial pattern. The wheel is positioned so that the wheel can contact the media sheet being gripped and cause the sheet to deform temporarily, thereby making the sheet more rigid.

1 . A sheet discharge roller assembly comprising:
 an upper cylindrical exit roller mounted on a rotatable drive shaft; and   a lower cylindrical pinch roller having a wheel attached to only one end so as to rotate synchronously with said pinch roller, said wheel having a diameter that is larger than that of the pinch roller and an outer circumferential edge composed of a plurality of protruding contact portions arranged in a radial pattern,   wherein said pinch roller has a length that is longer than the length of the exit roller and is moveable into contact with said exit roller so as to form a nip for gripping a print media to be discharged, and   said wheel is positioned so that said wheel can contact the media sheet being gripped and cause the sheet to deform temporarily, thereby making the sheet more rigid.   
     
     
         2 . The sheet discharge roller assembly of  claim 1 , wherein the outer circumferential edge of the wheel has a scalloped edge configuration. 
     
     
         3 . The sheet discharge roller assembly of  claim 1 , wherein the outer circumferential edge of the wheel has a serrated edge configuration. 
     
     
         4 . The sheet discharge roller assembly of  claim 1 , wherein the pinch roller is rotatably mounted to a housing, and is maintained in a spring-biased position by a U-shaped wire spring such that the pinch roller can be spring biased against the exit roller to define a nip therebetween. 
     
     
         5 . A sheet discharge roller assembly comprising:
 two upper cylindrical exit rollers mounted on a rotatable drive shaft; and   two lower cylindrical pinch rollers opposing said exit rollers, each pinch roller having a wheel attached to only one end so as to rotate synchronously with said pinch roller, said wheel having a diameter that is larger than that of the pinch roller and an outer circumferential edge composed of a plurality of protruding contact portions arranged in a radial pattern,   wherein each pinch roller is moveable into contact with a corresponding exit roller so as to form a nip for gripping a print media to be discharged, each pinch roller has a length that is greater than the length of the corresponding exit roller, and the pinch rollers are arranged so that the ends without the wheels are facing each other and the distance between the wheels is greater than the combined lengths of the exit rollers plus the distance between the exit rollers, whereby the wheels can contact the media sheet being gripped near the side edges of the sheet and cause the sheet to deform temporarily, thereby making the sheet more rigid.   
     
     
         6 . The sheet discharge roller assembly of  claim 5 , wherein the outer circumferential edge of the wheel has a scalloped edge configuration. 
     
     
         7 . The sheet discharge roller assembly of  claim 5 , wherein the outer circumferential edge of the wheel has a serrated edge configuration. 
     
     
         8 . The sheet discharge roller assembly of  claim 5 , wherein each pinch roller is rotatably mounted to a housing, and is maintained in a spring-biased position by a U-shaped wire spring such that the pinch roller can be spring biased against the corresponding exit roller to define a nip there between. 
     
     
         9 . An automatic document feeder comprising:
 an input tray for supporting a stack of media sheets;   an output tray;   a main media path for guiding a media sheet from the input tray to a scanning region and from the scanning region to the output tray;   a pickup unit for picking a sheet, one by one, from the stack of media sheets in the input tray and feeding the sheet into the main media path; and   a sheet discharge roller assembly configured to discharge the sheet onto the output tray, said sheet discharge roller assembly comprising:
 (a) at least one upper cylindrical exit roller mounted on a rotatable drive shaft; and 
 (b) at least one lower cylindrical pinch roller having a wheel attached to only one end so as to rotate synchronously with said pinch roller, said wheel having a diameter that is larger than that of the pinch roller and an outer circumferential edge composed of a plurality of protruding contact portions arranged in a radial pattern,
 wherein said pinch roller has a length that is longer than the length of the exit roller and is moveable into contact with said exit roller so as to form a nip for gripping a print media to be discharged, and said wheel is positioned so that said wheel can contact the media sheet being gripped and cause the sheet to temporarily deform, thereby making the sheet more rigid. 
 
   
     
     
         10 . The automatic document feeder of  claim 9 , wherein there are two spaced-apart upper cylindrical exit rollers mounted on the drive shaft and there are two lower cylindrical pinch rollers in opposing relationship to the exit rollers, each pinch roller being moveable into contact with a corresponding exit roller so as to form a nip, and
 wherein the pinch rollers are arranged so that the ends without the wheels are facing each other, and the distance between the wheels is greater than the combined lengths of the exit rollers plus the distance between the exit rollers, whereby the wheels can contact the media sheet being gripped near the side edges of the sheet and cause the sheet to deform temporarily, thereby making the sheet more rigid.   
     
     
         11 . The automatic document feeder of  claim 10 , wherein each pinch roller is rotatably mounted to a housing, and is maintained in a spring-biased position by a U-shaped wire spring such that the pinch roller can be spring biased against the corresponding exit roller to define a nip there between.