You can check the amount remaining in the toner cartridge according to the following, whenever you want to. It is recommended that you check the level before you start to print a large job.
<Device Information> <Cartridge Level> Check the amount remaining in the toner cartridge
Cartridge Level
Displays the amount remaining in the toner cartridges. Other internal parts may reach the end of their lifetime before the toner runs out.
NOTE
The displayed amount remaining in the toner cartridge can be used only as a guide and may differ from the actual amount.
<Device Information> 
Cartridge Level