| 摘要 |
To prevent uncontrolled movement or flutter of a trailing end of a sheet being removed by a chain conveyor from a delivery drum (7) of a printing system (1), the sheets are gripped by grippers (10) connected to cross struts (9) of two chains (8), and engaged by sheet engaging brushes (19, 22) or rollers or ducts (30, 34) with differential pressure application, such as compressed air, to urge the sheets against a sheet guide vane (13) or strip. To prevent interference with the grippers (10) on the chain conveyor, the sheet guide elements are lifted off from the sheets upon passage of the grippers by a cam-cam follower arrangement. The cams may be secured to the gripper structures in the form of cam curves (11), engaged by cam followers (17, 22) which pivot or tilt cross rods (15, 20) to lift the brushes off the sheets; or a cam (25; FIG. 2) can be placed on the delivery drum, controlling cam followers (27, 31) which, over a linkage, lift off the engagement elements (30, 34) when the grippers come therebeneath, but permit engagement thereof when the grippers have passed, to control movement of the trailing portions of the sheet.
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