What should I avoid using to prevent damage to the printer?

Do not use paper or print media designed for inkjet printers, as HP LaserJet products use fusers to bond dry toner particles at extreme heat, and inkjet paper could damage the product. Also avoid using envelopes with clasps, snaps, windows, wrinkled labels, or raised/metallic letterhead. Using non-HP media that does not meet specifications may require repairs not covered by the Hewlett-Packard warranty.