HP 3500 - Manual (Page 244)

TCP/IP
An internet protocol (developed by the U.S. Department of Defense) that has
become the global standard for communications.
toner
The fine black or colored powder that forms the image on the printed media.
transfer unit
The black plastic belt that transports the paper inside the printer and transfers
the toner from the print cartridges onto the paper.
tray
A receptacle for holding blank paper.
232 Glossary ENWW