| 摘要 |
A duplex printer (or copier) 10 has a copy sheet output path 92 through output rollers 84, curved chute 96, and output rollers 67 into output tray 86. Commonly utilizing a substantial portion thereof is a duplexing path 94 for returning copy sheets to be imaged on their opposite sides to make duplex copies. Rollers 67 alternatively, with reversal, feeds copy sheets into the duplex path 94, aided by rollers 84 at the path separation. The distance between output rollers 84 and the reversible ejecting rollers 67 along the chute 96 is substantial, preferably approximately one half the sheet dimension in the sheet feeding direction of the shortest sheet to be duplexed. The rollers 84 feed copy sheets through the copy sheet output path 92 to the reversible rollers 67 until about one half of the sheet extends out of their nip of these rollers 67. A reversed sheet can then be uninterruptedly reverse fed by, outside, of another sheet moving in the opposite direction in the same arcuate chute 96, for a substantial time period. Thus, a subsequent copy sheet may be fed downstream (upwardly) in the output path 92 simultaneously with, for a substantial time period, the reverse (downward) feeding of the preceding copy sheet into the duplex path 94, to enable slow, uncritical, reversals of rollers 67 even if the sheets are closely spaced in the output path. The duplex path 94 has an even greater path distance between the reversible rollers 67 and the first duplex path feed nip 90, which is separate from the rollers 84.
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