Jogging and normal force for sheet feeding

In a copier sheet feeder with a sheet stack holder adapted to retain a stack of sheets thereon, with front and rear ends, and with a sheet aligning front stack stop adjacent said front end, wherein intermittently operable bottom sheet feeding means are provided for feeding individual sheets from the bottom of a stack of sheets in said sheet stack holder in a sheet feeding direction past said front stack stop from said front end of said stack holder, and wherein sheet input means are provided to feed sheets into said sheet stack holder onto the top of a stack of sheets therein, and wherein a normal force applicator is provided to engage the top of a stack of sheets in said stack holder adjacent said front stack stop to urge said sheets downwardly against said bottom sheet feeding means, and wherein a jogger is provided to jog individual top sheets fed by said sheet input means into said sheet feeding holder up against said front stack stop, the improvement comprising:

• an integral combined normal force applicator and jogger,
• including deformable jogging roller means rotatably mounted adjacent said front stack stop for continuously engaging the top of a stack of sheets in said sheet stack holder and for frictionally driving the top sheet of a stack of sheets in said sheet stack holder against said front stack stop,
• further including drive means for continuously rotatably driving said jogging roller means, and
• further including pressure means for lightly continuously pressing said jogging roller means against the top of a stack of sheets in said sheet stack holder with sufficient force to provide a normal force for said bottom sheet feeding means and with sufficient force for said jogging roller means to frictionally drive a top sheet against said front stack stop but with a sufficiently low force to allow said jogging roller means to continuously slip on a top sheet which is against said stack stop without buckling or driving the top sheet beyond said front stack stop,
• whereby a continuous stacking of incoming top sheets to said sheet stack holder and a continuous normal force is simultaneously provided by said jogging roller means;
• wherein said bottom sheet feeding means includes a frictional sheet feeding member extending under said sheet stack and slightly above the plane of said sheet stack holder, and
• wherein said jogging roller means comprises a spaced plurality of top sheet engaging wheels extending across said sheet stack holder transversely of, but not overlying, said frictional sheet feeding member with two of said wheels positioned adjacent opposite edges of said frictional sheet feeding member to buckle sheets thereover and to concentrate said normal force at said edges of said frictional sheet feeding member.

In a copier sheet feeder with a sheet stack holder adapted to retain a stack of sheets thereon, with front and rear ends, and with a sheet aligning front stack stop adjacent said front end, wherein intermittently operable bottom sheet feeding means are provided for feeding individual sheets from the bottom of a stack of sheets in said sheet stack holder in a sheet feeding direction past said front stack stop from said front end of said stack holder, and wherein sheet input means are provided to feed sheets into said sheet stack holder onto the top of a stack of sheets therein, and wherein normal force applicator means are provided to engage sheets in said stack holder adjacent said front stack stop to urge said sheets downwardly against said bottom sheet feeding means, the improvement wherein:

• said bottom sheet feeding means includes a frictional sheet feeding belt member extending under said sheet stack and slightly above the plane of said sheet stack holder, with exposed opposite edges extending in said sheet feeding direction, and
• wherein said normal force applicator means extends across transversely of said sheet stack holder, but not overlying said frictional sheet feeding member, and said normal force applicator means presses said sheets downwardly against said opposite edges of said frictional sheet feeding member and buckles said sheets thereover to concentrate said normal force at said opposite edges of said frictional sheet feeding member.