| 摘要 |
<p>DOCUMENT FEEDER WITH IMPROVED VACUUM SYSTEM A document feeder defines a sheet path along which a document sheet is fed across a platen of a copier/duplicator, for example, in order to copy the sheet. An oscillating vacuum tube feeds sheets from a supply into the sheet path. The feeder includes a platen vacuum transport having vacuum belts that move the sheet across the platen. The vacuum transport has a first vacuum plenum and a second vacuum plenum located along the sheet path. The first vacuum plenum has a relatively high level of vacuum to insure lifting of the sheet onto the vacuum belts. The sheet is then transported into the area where it comes under the influence of the second vacuum plenum, The second vacuum plenum has a somewhat lower level of vacuum, but it is sufficient to retain the sheet on the belts as the belts drive the sheet into engagement with a registration member. One vacuum blower is used to establish a vacuum in the vacuum tube and another such blower establishes vacuum in the two plenums. Two control valves regulate the flow of air to the blowers from the vacuum tube and one of the plenums. The vacuum system provides good control and usage of applied vacuums with small fluctuations in vacuum levels in the vacuum conduits.</p> |
