Brother HL-1435 User Manual page 33

Make sure the envelope is straight as you insert it sideways in the manual feed slot. If it is not,
the envelope may not be fed properly, resulting in a skewed printout or a jam.
Do not put more than one envelope in the manual feed slot at any one time, or it may cause a
jam.
Put the envelope in the manual feed slot with the side to be printed face up.
6
After the printed envelope comes out of the printer, the printer will wait until you put in the next
envelope. Repeat Step 5 for each envelope you want to print.
7
After you finish the print job, close the rear cover.
Envelope joints that are sealed by the manufacturer should be secure.
All sides should be properly folded without wrinkles or creases.
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