Brother MFC-9450CDN - Manual (Page 139)

Troubleshooting and routine maintenance
123
C
Envelope Creases
a
Open the back cover.
b
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.
c
Close the back cover and re-send the print job.
Note
When you have finished printing, open the back cover and reset the
two gray levers back to the original position.
Examples of poor print
quality Recommendation
ABCDEFG
EFGHIJKLMN