To print on both sides of the paper from the manual feed slot, Caution

To print on both sides of the paper from the manual feed slot
Before re-inserting the sheets, you have to straighten them, or you may get paper
feed errors.
The use of very thin or very thick paper is not recommended.
When you use the Manual Duplex function, it is possible that paper jams may
occur or print quality might not be satisfactory.  If a paper jam has occurred,
please refer  to “PAPER JAMS and how to clear them” in Chapter 4.

Select the required manual duplex printing mode and manual feed mode from the

Using both hands, insert the paper into the manual feed slot with the side to be
printed first facing upwards.
Follow the instructions on the computer screen.
Repeat this until you have printed all the even numbered pages.

Remove the printed even numbered pages from the output tray and re-insert them in
order into the manual feed slot, loading the paper with the side to be printed (blank
side) face up, and the top of the printed side towards the printer.  Follow the
instructions on the computer screen.
Fig. 1-22  Paper operation for the manual feed slot

Repeat action 3 until you have printed all the odd numbered pages on the reverse
side of the paper.