Vacuum transfer apparatus for rotary sheet-fed printing presses

摘要

A vacuum assisted sheet transfer assembly has an array of support bars which support the unprinted side of a freshly printed sheet along a sheet transfer path. The support bars overlie the airflow inlet of a manifold housing, with the longitudinal axis of each support bar extending across the sheet transfer path. The support bars provide smooth surfaces for engaging and supporting the unprinted side of the sheet material as it is pulled along the transfer path while simultaneously limiting the flow of inlet air through elongated inlet apertures. As air is drawn through the inlet apertures, the unprinted side of the sheet is sucked into engagement with the support bars as it moves along the sheet transfer path. The sheet transfer assembly eliminates the need for conventional skeleton wheels and the like. Marking, smearing and smudging are prevented since the printed side of the sheet is not handled or contacted in any way as the sheet is conveyed along the sheet transfer path.