Sheet feeder for printing bound sheets

Abstract

A sheet feeder for use with an offset printing device that is capable of feeding sheets that are bound together along a common edge is disclosed herein. The sheet feeder generally comprises a stack holder for holding a stack of bound sheets along their commonly bound edges, an endless conveyor formed from parallel chains that are driven between the top of the bound sheets and the impression cylinder of the offset printing device, a set of driving and pressure rollers connected between the parallel chains of the conveyor and rotating with it, and a suction gripper movable perpendicularly with respect to the sheet stack top for lifting the respective topmost sheet. In operation, the suction gripper lifts a sheet, and then one of the driving and pressure rollers slides under the sheet and carries it to the impression cylinder, whereupon it acts as a pressure roller during the printing process. After the sheet is printed, the driving and pressure roller automatically turns the sheet off of the stack so that the process can be repeated.

Dependencies are inferred from the claim text.