HP 2 - Manual (Page 58)

To prevent paper from falling out of the tray, pull out the Out tray extension, then
unfold the Out tray extension stop.
1. out tray extension and out tray extension stop
folding the paper trays
Follow these steps to refold the paper trays:
1. Remove paper or other media from the paper trays, then turn off the printer .
2. Raise the printer cover.
3. Fold the Out tray extension stop, then push the Out tray extension into the Out
tray.