Resetting the toner on a Brother laser printer occurs automatically when you change the toner cartridge. However, there are instances where you may need to reset the toner level without actually changing the cartridge. If you cover the holes of your toner cartridge, it keeps the printer from checking the toner level. The Brother utilities on your computer will perceive it as reset and the toner cartridge is full. Covering the toner level sensors on your cartridge allows you to print additional documents after the Brother printer has warned you that the toner is low and has stopped printing additional documents.
Turn off the Brother printer.
Open the front panel of the printer to access the toner cartridge.
Remove the toner cartridge and carrier from the Brother printer by pulling it straight out of the printer.
Press the release tab in the bottom-left corner of the toner carrier and pull the cartridge from the carrier.
Locate the round toner level sensor holes on the both the left and right sides of the cartridge. They are near the middle of each side of the cartridge.
Cover both holes with white address labels that are cut to fit. Alternatively, you can use black electrical tape to cover the holes. The goal is to cover the holes so that light is blocked from entering the toner cartridge through the holes.
Push the toner cartridge back in to its carrier until it clicks.
Slide the toner back into the printer and close the front panel.
Turn the Brother printer on and verify that the low toner warning light is no longer active.
Be sure to change the toner cartridge when you start noticing prints becoming more and more faint. Failure to do so could damage your Brother printer by running it out of toner.