Epson Stylus Photo 1280 Printer Basics Manual page 15

2. Set your printer's thickness lever to the + position. (Remember to move the
thickness lever back to the 0 position when you're done printing envelopes.)
3. Select
Plain paper
as the Paper Size setting. See page 16 (Windows), page 22 (Macintosh OS X), or
page 19 (Macintosh OS 8.5.1 to 9.x) for more information.
as the Media Type setting and choose the correct envelope size
9