Ricoh Aficio Color 4006 Operating Instructions Manual page 76

Reference
For functions that cannot be used together with this function,
The resulting copy image will differ according to the direction in which you set your original (lengthwise p or
widthwise l).
Originals
*1 The illustrations show the directions of copied images on the front and back, not the directions of delivery.
1
Press the [Duplex/Combine] key.
2
Press the [1 Sided → 2 Sided] key.
see page 88.
Orientation
Duplex—Making 2 Sided Copies
Result*1
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