the sheets on chain guided gripper bars the gripper bars are fixed respectively to two chain links arranged indirectly beside each other the forces acting on the gripper bars are more evenly distributed application_number US 5400308 A description referring now to the figures of the drawing in detail and first particularly to fig1 thereof there is seen a sheet processing machine represented here by a printing press 1 the machine has a feeder 2 at least one printing unit 3 and 4 and a delivery 6 sheets 7 are removed from a sheet stack 8 and separated or overlapping are fed over a feed table 9 to the printing units 3 and 4 the printing units each contain in a known way a plate cylinder 11 12 the plate cylinders 11 and 12 each have a device 13 14 for fixing flexible printing plates furthermore each plate cylinder 11 12 is assigned a device 16 17 for fully automatic or semiautomatic printing plate exchange the sheet stack 8 rests on a stack board 10 that can be raised under control the sheets 7 are removed from the top of the sheet stack 8 by means of what is known as a suction head 18 which inter alia has a number of lifting and dragging suckers 19 21 for separating the sheets 7 furthermore blowing devices 22 for loosening the upper sheet layers and sensing elements 23 for stack tracking are provided in order to align the sheet stack 8 in particular the upper sheets 7 of the sheet stack 8 a number of side and rear stops 24 are provided the sheets are transported though the machine by way of a number of sheet carrying cylinders equipped with gripper devices e g a feed.