Abstract: With a sheet stacker to stack sheets cut by a sheet cutter into stacking station, sheets cut by a sheet cutter are transferred by a conveyor with a fixed sheet interval, a clamping device clamps a base position near the tail end of the sheet during transfer of the sheet, and the sheet transfer speed is reduced to an optimum speed needed for stacking the sheet into stacking station orderly. The clamping device has a rotating device having free rolls at its end and a slowdown roll, and clamps the sheet once during each revolution of the rotating device, by contact of the free rolls with the slowdown rolls.

Abstract: With a sheet feeding apparatus, to feed sheets piled up in a hopper, piece by piece, to a printing press from a suction conveyor installed at bottom of the hopper, having motor for driving the suction conveyor, sensor positioned above the suction conveyor to detect front edges of sheets, and a control unit to equalize speed of motor with speed of plate cylinder of the said printing press and to adjust phase of sheet to phase of the plate cylinder, sheet feeding accuracy is improved.

Abstract: With four CCD (charge coupled device) based cameras and flashing devices, each of which is installed with an angle against the optical axis of a camera, four corners of sheets being transferred line are photographed. Each of four corner detecting sections detects absolute coordinates of a corner based on differences in brightness of standstill picture of sheet corner taken by each camera. Then, based on the detected absolute coordinates of sheet corners, sheet dimensions computing section calculates lengths, widths and diagonal dimensions of sheets.