Brother HL-3400CN Series User Manual page 65

Note
If you use paper that does not meet the specifications listed in this User's
Guide the life of the various consumables and parts may be reduced.
!
Caution
When you feed thin paper in the Long Edge Feed direction, paper jams
may occur. If a paper jam occurs, feed the paper in the Short Edge Feed
Direction.
Using Transparencies
When you print on transparencies which have a line tape on the edge, be
sure to remove the tape before loading.
If you do not remove the tape, the transparency may skew.
CHAPTER 3 BEFORE WORKING WITH THE PRINTER
3–11