Epson AcuLaser MX20DNF - Manual (Page 39)

4. Insert the loaded paper cassette back into the printer.
5. Raise the stopper.
Note:
When you use the paper that is longer than A4 size, do not raise the stopper. To prevent printouts
from being stacked and pushed out of the output tray, every time the printer ejects a couple of the
printouts, remove them from the tray.
Epson AcuLaser MX21/MX20 Series User's Guide
Paper Handling 39