Lexmark All in One Printer - Manual (Page 64)

64 Loading Print Materials
5 Flex a stack of envelopes back and forth.
6 Straighten the edges on a level surface. Press down the
corners to flatten them. Fan the envelopes. This prevents the
edges of the envelopes from sticking together and helps them
feed properly.
N OTE : When you load envelopes, do not exceed the
maximum stack height of 64.7 mm (2.55 in.).
The envelope feeder holds a maximum of 85
envelopes (75 g/m
2
, 20 lb bond).