The toner laser drum assembly unit has a fairly long life cycle, as it lasts through 20,000 pages before it must be replaced. Even so, certain factors will affect its true usage limits. For example, the quality of the toner, the ambient temperature and paper type used most often in printjobs can either increase or decrease the average length of service. You will know when the laser unit's time is really up when the "CHANGE DRUM SOON" message appears on the control panel display and degraded quality is evident on your printouts.
1) Open the front cover on the multifunction printer.