Sheet stack pre-feeder

Device for feeding a stack of sheets, the device comprising:

• a stack support including a substantially horizontal stack support surface, said stack support surface including a first end and a second end;
• guide wall means extending from said stack support surface and for containing the stack of sheets with a edge of each of the sheets being in contact with said stack support surface and the planes of the stack of sheets in a substantially vertical position;
• guide means positioned in said stack support surface and for stepwise moving the stack of sheets in contact with said stack support surface from said first end to said second end of said stack support surface, said guide means moving the sheets in a direction substantially perpendicular to the edge of each of the sheets and to a plane of each of said sheets, and said guide means includes a guide belt having a strand positioned in and substantially parallel to said stack support surface, said strand of the guide belt being in contact with the edges of the sheets of the stack and said guide belt moving substantially perpendicular to the edges of the sheets;
• sheet feed means positioned at said second end of said stack support surface and for individually removing a single sheet from the stack of sheets and also feeding said removed sheet into a deflecting device and onto a substantially horizontal transport device, said sheet feed means including a feed conveyer having a side substantially parallel to the single sheet and in contact with a side of the single sheet, said feed conveyer traveling around a decollating deflecting roller, said decollating deflecting roller being positioned adjacent said second end of said stack support surface, said feed conveyer also travelling around a drive roller, said drive roller being positioned at a spaced distance away from the stack, downstream of said removing of the single sheet and above the sheet stack, also said side of said conveyor travelling around an articulating roller positioned adjacent to an upper third section of the sheets of the stack, said side of said conveyer including a decollating section between said decollating deflecting roller and said articulating roller, said decollation section of said feed conveyer being in a plane positioned at an angle greater than 5 degrees and less than 30 degrees from vertical and brings about a continuous sheet feed upward to said deflecting device due to frictionally engaged contact with the single sheet, said side of said feed conveyer also including a feed section between said drive roller and said articulating roller, said feed section of said feed conveyer being more angled with respect to vertical than said decollation section, and said articulated rollers being eccentrically mounted on an articulated shaft.

A method for feeding a stack of sheets, the method comprising the steps of:

• moving the stack of sheets against a feed conveyor, said moving being in a substantially horizontal direction with the planes of the sheets being substantially vertical, and said feed conveyor having a substantially vertical surface coming into contact with the stack of sheets, said substantially vertical surface having a decollating section, and a feed section above said decollating section, an angle of said feed section being offset from said decollating section to cause the sheets to fan-out during said moving against said feed conveyor;
• moving said surface of said feed conveyor substantially upwards to also move a single sheet of the stack to a position away from the stack, said moving of said surface of said feed conveyer being in pulse-like acceleration steps to cause the single sheet to break loose from frictional contact with the stack;
• providing an articulating roller positioned against said surface of said feed conveyor and between said feed section and said decollating section;
• and
• oscillating said articulating roller in and out of one of a plane of said feed section and said decollating section to also cause the single sheet to break loose from frictional contact with the stack.