Conveyors for box making machines

摘要

A vacuum belt conveyor sequentially delivers sheet articles to a digital printer. The sheets are held in position by vacuum on the underside of the sheets through apertures in the belts and covered by the sheets. A plurality of independent plenums on the underside of the belt have chambers respectively communicating with rows of apertures extending along the belt. Vacuum is selectively applied from a manifold only to the plenum chambers that supply apertures that are covered by the sheets so that the ink from the printer will not be directed from its intended position on the sheet by vacuum from adjacent uncovered belt apertures. The sheets are fed to the conveyor in synchronism with the conveyor speed by a timed feeder so that the sheets are carried by the conveyor with a predetermined gap between the sheets and no belt apertures in the gap. A sensor counts the apertures in the belt and activates the feeder at predetermined time intervals.

主权项

1. Apparatus for digital printing of planar articles comprising in combination:
a digital printer, a conveyor having a conveyor belt movable along a generally horizontal path for moving planar articles along said path to said printer, said belt having a plurality of apertures for introducing a vacuum to the underside of articles on said belt to hold the articles on the belt, and means for opening a number of said apertures to a source of vacuum and for closing other apertures in the belt to a source of vacuum while said first number of apertures are open to said vacuum source, and means for successively feeding articles on the conveyor belt such that there are gaps between successive articles on the belt and said gaps do not contain any apertures.