You can load
envelopes in Cassette 2 (lower cassette) as described here. You can
print on plain paper envelopes in this size:
No.
10 (4.1 × 9.5 inches
[105 × 241 mm]).
You can also load a single envelope in the rear paper
feed slot, as described in that section.
Note: Do not
remove or insert the paper cassette during printing.