Epson EPI-4000 User Manual page 114

Loading Paper
9. To print a single sheet, insert it into the manual feeding slot
using enough pressure so that the page bows slightly in the
middle, until it is drawn into the printer.
To print an envelope, insert it into the paper slot using enough
pressure so that the envelope bows slightly in the middle, until
it is drawn into the printer. Keep the envelope aligned against
the left paper guide.
Paper Handling
3-20