| 摘要 |
The impression cylinder (2), which together with the cylinder (1) that prints the image, forms the printing nip, co-operates with two transfer cylinders (3, 4) which feed or remove the sheets, and has an essentially closed cylindrical circumferential surface, into which, at the beginning of each impression segment, a suction strip (5, 6) is inset to apply suction to the front edge of a shee t. The two transfer cylinders (3, 4) are similarly provided with suction strips (7, 8; 13, 14) which are arranged in good register with the suction strips (5, 6) of the impression cylinder (2), and moreover have dipping grippers (10, 12; 16, 18), which are located in gaps in the dipping strips. Sheet transfer to and from the impression cylinder (2) is effected by alternately switching on and off the suction air at the relevant suction strips. As they pass the printing nip, the dipping grippers of the transfer cylinders occupy their lowered position, whilst away from the printing nip, they occupy their raised position, in order to hold the sheets while th e suction air of the relevant suction strip is switched off.
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