GATELESS SHEET INVERTERS FOR DUPLEX PROCESSING

摘要

A device for inverting a sheet along a path in an electric photographic printing machine. A gateless sheet inverter is provided in which a curved portion of a sheet path branch intersects a second portion of the sheet path to form a curved inverter throat. As the sheet is driven from the curved branch portion of the path into the throat portion the beam strength of the sheet causes the trail edge of the sheet to flip toward a second nip leading to the second sheet path. A pair of reversing rolls captures the lead edge of the sheet to be inverted and then reverses to drive the sheets out of the second nip formed by a tri-roll arrangement. A sheet having a radius of curvature equal to or greater than the radius of curvature of the throat will be guided along the throat baffle and fed through the second nip. To further assist in assuring the trail edge flips to the second sheet path an air knife can be added at the intersection of the path branches to assist in moving the trail edge into the second path branch. A fixed deflector can also be added and configured so that the trail edge of the sheet is guided into the second branch of the sheet path to increase the latitude of sheet curvature that can be handled by the device, the deflector further having a curved radius on the portion of the deflector contacting the sheet so that coated sheets are not damaged.