You can check the level of remaining toner 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 Status> <Cartridge Level> Check the toner level
Toner Level
Displays the amount of remaining toner. Depending on the environment in which your machine is located, other parts may reach the end of their lifetime before the toner runs out.
<Device Status> 
Toner Level