Dell 1130 Laser Mono Printer Troubleshooting Manual page 42

When selecting envelopes, consider the following factors:
Weight: The weight of the envelope paper should not exceed 90 g/m
Construction: Prior to printing, envelopes should lie flat with less than 6 mm curl, and should not contain air.
Condition: Envelopes should not be wrinkled, nicked, nor damaged.
Temperature: Use envelopes that are compatible with the heat and pressure of the machine during operation.
Use only well-constructed envelopes with sharp-and well-creased folds.
Do not use stamped envelopes.
Do not use envelopes with clasps, snaps, windows, coated lining, self-adhesive seals, or other synthetic materials.
Do not use damaged or poorly made envelopes.
Be sure the seam at both ends of the envelope extends all the way to the corner of the envelope.
Acceptable
1.
Unacceptable
2.
Envelopes with a peel-off adhesive strip or with more than one flap that folds over to seal must use adhesives
compatible with the machine's fusing temperature about 170°C (338 °F) for 0.1 second. The extra flaps and strips
might cause wrinkling, creasing, or jams, and may even damage the fuser.
For the best print quality, position margins no closer than 15 mm from the edges of the envelope.
Avoid printing over the area where the envelope's seams meet.
Transparency
To avoid damaging the machine, only use transparencies designed for use in laser printers.
Transparencies used in the machine must be able to withstand machine's fusing temperature.
Place them on a flat surface after removing them from the machine.
Do not leave unused transparencies in the paper tray for long periods of time. Dust and dirt may accumulate on
them, resulting in spotty printing.
To avoid smudging caused by fingerprints, handle them carefully.
2
otherwise, jam may occur.