Brother HL 4150CDN - Manual (Page 22)

Printing Methods
16
1
d
Put envelopes in the MP tray and make sure:
 The envelopes stay under the maximum paper mark (1).
 The envelope edge positions between the arrows (2).
 The side to be printed on must be face up.
Note
Do not put more than 3 envelopes in the MP tray at any one time, as it may cause a jam.
e Open the back cover (face-up output tray).
f
Pull down the two gray levers, one on the left-hand side and one on the right-hand side, to the envelope
position as shown in the illustration below.
1
2