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 print jobs 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.
Instructions
3) Remove the new laser unit from its packaging.
4) Rock the laser unit from one side to the other six times so that the toner inside the cartridge is distributed evenly.
5) Pull the protective plastic part out from the new laser unit.
Recycle the used laser unit according to federal, state and city regulations.