SHEET-FED MACHINE Russian patent published in 2000 - IPC

FIELD: manufacture of printing machines. SUBSTANCE: impression cylinder 2 forming together with image printing cylinder 1 of printing gap is engageable with two offset cylinders 3 and 4 which feed or withdraw sheets, and has essentially closed cylindrical surface in which suction head-piece 5, 6 is installed at beginning of each printing segment for inflow of sheet front edge. Both offset cylinders 3 and 4 are similarly provided with suction head-pieces 8, 8; 13, 14 which are located with accurate observation of registration with suction head-pieces 5, 6 of impression cylinder 2 and have in addition, immersion grippers 10, 12; 16, 18 which are located in gaps of immersion head-pieces. Sheets are transferred onto impression cylinder 2, and from it they transferred with help of mutual engagement of exhaust ventilation to respective suction head-pieces and its disengagement. During passage of printing gap, immersion grippers of transfer cylinder assume their immersed position, whereas they assume their raised position when being out of printing gap to fix sheets during disengagement of exhaust ventilation of respective suction head piece. EFFECT: avoided defects occurring in impression cylinders with recesses. 10 cl, 11 dwg