If envelops were creased after they have been printed, please take the following countermeasures:
Firstly, please change a paper size setting to "DL Long Edge" at printer driver properties. And then put in envelopes sideways, and print again.
At the back of the printer, open the back output tray and push down the blue tabs at the left and right hand sides (as shown in the figure below). When you have finished printing your envelopes, close the back output tray to reset the two blue tabs back to their original position.
