HP Color LaserJet 8550 Multifunction Printer series - Manual (Page 289)

EN
Replacing the drum cartridge 289
Replacing the drum cartridge
When the imaging drum needs to be replaced, the
REPLACE THE
DRUM CARTRIDGE
message appears in the copy module touch panel
display. The copy module is still able to produce copies with this
message displayed. However, copy and print quality may begin to
degrade. Hewlett-Packard recommends replacing the drum when the
message appears.
Figure 59 Drum cartridge message - Basic Features screen
Figure 60 Drum cartridge message - instructions