| 摘要 |
<p>Disclosed herein is a vacuum transport means for feeding sheets along a predetermined path into abutment with a registration member. To minimize damage to the leading edge of the sheet by the registration member, yet assure reliable transport of the sheets to the registration member, the vacuum transport means is provided with two vacuum plenums (82, 84), one upstream in the sheet path relative to the other. Vacuum control means are provided to control the relative level of vacuum supplied to the respective plenums so that the upstream plenum applies a relatively high vacuum force to a sheet presented to the transport means for feeding, and so that the downstream plenum applies a lesser vacuum force to the sheet during transport, thereby a sheet can slip relative to the vacuum transport belt when the sheet's leading edge engages the registration member (34). The vacuum control additionally functions to decrease the vacuum supplied to the upstream plenum at a time when a sheet is transported under the influence of the downstream plenum.</p> |
