HP Color LaserJet 3800 Printer series - Manual (Page 34)

The supplies gauge shows the consumption levels of print cartridges (black, cyan, magenta, and yellow).
When a non-HP print cartridge is installed, a ? might appear instead of the consumption level. The
supplies gauge appears whenever the printer shows the Ready state, and whenever the printer shows
a warning or error message concerning a cartridge.
20 Chapter 2 Control panel ENWW