HP 3550 - Manual (Page 97)

8. Go to the printer. When the MANUAL FEED prompt appears, remove any blank paper
from Tray 1. Insert the printed stack with the blank side up, top edge in first. You must
print the second side from Tray 1.
NOTE Do not discard any blank sheets from the printed stack.
9. If prompted by a message at the control panel, press .
NOTE If total sheets exceed the Tray 1 capacity for manual duplex jobs, feed the top 100 sheets
first and press . When prompted, feed the next 100 sheets and press . Repeat as
necessary until all the sheets from the output stack have been loaded into Tray 1.
ENWW 2-sided (duplex) printing 85