HP 3800 - Manual (Page 73)

Printing envelopes from tray 1
Many types of envelopes can be printed from tray 1. Up to 10 envelopes can be stacked in the tray.
Printing performance depends on the construction of the envelope.
In the software, set margins at least 15 mm (0.6 in) from the edge of the envelope.
CAUTION Envelopes that contain clasps, snaps, windows, coated linings, exposed self-stick
adhesives, or other synthetic materials can severely damage the printer. To avoid jams and
possible printer damage, never try to print on both sides of an envelope. Before you load
envelopes, make sure that they are flat, undamaged, and not stuck together. Do not use
envelopes that contain pressure-sensitive adhesive. To avoid jams, do not remove or insert
envelopes during printing.
To load envelopes into tray 1
1. Open tray 1.
2. Slide out the tray extender and, if necessary, open the additional tray extender.
ENWW Configuring trays 59