초록 ▼

To permit, selectively, multi color prime printing or prime-and-verso printing, two rubber blanket cylinders (5, 6) each in engagement with a respective cylinder (3, 4) cooperate with a single printing or impression cylinder (7), and an engagement element (23, 24, 28) such as a roller (23, 24) or a

To permit, selectively, multi color prime printing or prime-and-verso printing, two rubber blanket cylinders (5, 6) each in engagement with a respective cylinder (3, 4) cooperate with a single printing or impression cylinder (7), and an engagement element (23, 24, 28) such as a roller (23, 24) or a compressed air supply (28); the rubber cylinder can be engaged with the impression cylinder or, respectively, separated therefrom. The impression cylinder carries a rubber blanket to receive printing information from one (5) of the blanket cylinders to effect verso printing during one operation phase, when the engagement element controls engagement of a sheet about the impression cylinder the other rubber blanket cylinder being engaged when the sheet reaches the printing line for verso printing; during a subsequent operation phase of the machine, the second rubber blanket cylinder (6) is separated from the impression cylinder to prevent smearing contact therewith, while the first rubber blanket cylinder (5) transfers printing information from its associated plate cylinder (3) to the rubber blanket on the impression cylinder. The sheet feed mechanism feeds a sheet only for every alternate operating phase. In normal operation, with a sheet fed for each revolution, the impression cylinder receives no ink and multi color prime printing can be effected by the two rubber blanket cylinders (5, 6). Double inking can be obtained by selectively lifting off both rubber blanket cylinders for alternate revolutions and feeding a sheet, only for every other revolution of the printing system, with, then, both rubber blanket cylinders engaging the sheet looped about the impression cylinder.

대표청구항 ▼

Method of printing in prime and verso printing mode on a substrate sheet by a printing machine having two plate cylinders (3,4; 41, 42); two rubber blanket cylinders (5, 6; 43, 44) in continuous surface engagement with an associated respective plate cylinder; a printing or impression cylinder (7, 45

Method of printing in prime and verso printing mode on a substrate sheet by a printing machine having two plate cylinders (3,4; 41, 42); two rubber blanket cylinders (5, 6; 43, 44) in continuous surface engagement with an associated respective plate cylinder; a printing or impression cylinder (7, 45) carrying a rubber blanket capable of receiving printing information, all said cylinders having essentially the same diameter comprising: controlling, respectively, engagement and disengagement of said rubber blanket cylinders and the impression cylinder by (a) separating one (5) of the rubber blanket cylinders and the impression cylinder (7,45) during a first or printing phase of revolution of the impression cylinder while engaging a substrate sheet against the impression cylinder; (a1) engaging said rubber blanket cylinder with the rubber blanket of the impression cylinder for transferring of printed information from the rubber blanket cylinder to the rubber blanket of the impression cylinder during a second phase of operation and when no substrate sheet is positioned between the rubber blanket cylinder and the impression cylinder to effect verso printing on said substrate sheet; (a2) transferring printing information from the rubber blanket cylinder to the rubber surface of the impression cylinder by engagement of said rubber blanket cylinder (5, 43) with the impression cylinder (7, 45) during a second, or non-printing operating phase of the machine; (b) engaging the other (6, 44) rubber blanket cylinder against the printing or impression cylinder (7, 45) with the substrate sheet therebetween for prime printing on said substrate sheet during said first operating phase; (b1) separating the other rubber blanket cylinder (6, 44) from the printing or impression cylinder (7, 45) during said second operating phase to prevent ink smear by the second rubber blanket cylinder on the printing information transferred to the rubber surface of the impression cylinder by the first rubber blanket cylinder (5,43).