Brother TN450 Compatible High Yield Black Toner Cartridge

Toner sensor needs to be reset. Please do the following steps to reset the toner sensor.

Open the front cover and leave open while completing the following steps.
Turn the printer off.
Hold the 'go' button (or "start' button) while turning the printer on. All panel lights should be on.
Release the 'go' button (or "start' button).
Press the 'go' button (or "start' button) 2 times.
Pause.
Press the 'go' button (or "start' button) 5 times.
The toner light should be off.
The paper light should be on or flashing.
Close cover. The ready light should be the only light on.