Dell 5210n Mono Laser Printer User Manual page 22

2. Remove all envelopes.
If the jammed envelope has entered the printer and cannot be pulled out, remove the envelope feeder.
a. Lift the envelope feeder up out of the printer, and then set it aside.
b. Remove the envelope from the printer.
NOTE: If you cannot remove the envelope, the print cartridge will have to be removed. See
information.
c. Reinstall the envelope feeder. Make sure it snaps into place.
3. Flex and stack the envelopes.
4. Load the envelope feeder.
5. Adjust the guide.
200 and 201 Paper Jam Remove Cartridge for more