a pre - gripper driving device for a pre - gripper cyclically driven oscillatingly and serving for transporting individual sheets in a sheet - processing machine , includes sheet grippers disposed at a free end of a rocking lever pivotable about a pivot pin fixed to a frame , the sheet grippers being movable relative to a gripper support about a gripper shaft aligned parallel to the pivot pin , for closing and opening the sheet grippers , and an activatable and regulatable drive for producing the movement of the grippers , the drive , on one hand , being connected to the sheet grippers and , on the other hand , being supported on one of the rocking lever and the frame ; and a printing unit , a digital printing unit , a rotary printing machine and a multicolor rotary printing machine , respectively including the pre - gripper driving device .