摘要 |
To permit, selectively, multi-color prime printing or prime and verso printing on printing machines having plate blanket, and printing cylinders of the same diameter, the printing cylinders (8,9;51,52,53;77) have a rubber blanket thereon to receive printing information from the blanket cylinders (6,7;48,49,50;75,76) during one phase of operation and transferring this information to the sheet by engagement with the sheet supply or transport cylinders (12,60,78) which are formed with surfaces permitting them to operate as impression or printing cylinders, sheet supply being arranged to provide sheets in this mode of operation for every two revolutions of the cylinders only, to permit information transfer during the intervening idle, or non-printing phase or revolution. To prevent smearing, or transfer of unwanted ink, the blanket cylinders are supported in bearings which can rock about the center of rotation of the associated plate cylinders, under control of a control unit (C) to be placed in, or out of engagement with the printing or impression cylinders, in dependence on desired operation - multi-color prime printing or prime-and-verso printing under control of the control unit (C).
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