Brother printers that use toner instead of ink can print thousands of pages from a single cartridge. But toner printers also are inclined to display a "low on toner" message and stop functioning. If you want to overcome this issue, you need to reset the toner.
Take out your Brother's toner cartridge. To do this, press the tab next to your device's cartridge and remove the cartridge.
Place opaque tape on the printer's sensor light. To find this sensor, look on the side portion of your printer. Put the cartridge back in. Check to see if the printer works.
Put the cartridge of your toner in and take it out five times. This fools your device into believing you've installed a fresh toner cartridge. Once your printer senses something that functions as a fresh cartridge, it begins to print in a normal manner once again.