Epson Stylus 1500 Reference Manual page 30

5. If you are using the manual feed slot, position the right
edge guide to the right of the arrow mark on top of the
manual feed slot. Then slide the left edge guide to match
the envelope's width.
6. Load the envelope with the flap edge first and the printable
surface facing up.
The printer loads the envelope automatically. If the
envelope does not load straight, press the Load/Eject
button to eject it. Then try loading it again.
7. Change the printer driver settings so they are appropriate
for the envelopes you loaded. (See your Setup and Software
Guide.)
Note:
Before printing on envelopes from DOS using the sheet feeder, the
printer must be in the envelope printing mode. To enter this mode,
load a single envelope from the sheet feeder and then eject it by
pressing the Load/Eject button. The printer will now feed envelopes
correctly.
Paper Handling
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