Sometimes when we the machine does not work, the first thing that pops into our mind is that maybe it is time to replace the old machine by the new one. Likewise, when the warning light of "Toner Low", "Replace Toner" or "Toner Ended" keep popping up but you find that the printer cartridge is still lying in your printer, you cannot help yourself from questioning the quality of the toner and start to scold the printer seller. However, maybe the printer seller does not deserve your scold because usually, this kind of problem has nothing to do with the quality of the toner or the printer. A few steps to reset the ink cartridges can help you to get rid of those annoying "toner low" signals.

For the Brother DCP/MFC Series printers:
1. Open the front toner compartment door.
2. The printer screen should read "front cover is open".
3. Press the "clear" button on the printer's front panel.
4. Printer will say "Replace Drum?"
5. Here do not press 1 but instead type in "*00" on the keypad. Star zero zero.
6. The screen will say "Accepted". Close the door and it will reset the low toner message.

For the Brother HL Series printers:
1. Open front door.
2. Turn off printer.
3. While holding down the GO button, turn printer back on.
4. When all four LEDs light up release GO button. All LEDs will turn off.
5. Press the GO button 2 times. The 3 LEDs (toner, drum, paper) will light up solid.
6. Press the GO button 5 times.
7. Paper light will be blinking.
8. At this point the toner end-of-life condition has been reset. Close front door.

Here is a little tip for you: timing is important here so don't pause between button presses. Besides, different printers and toners should be reset with different methods. The above method is suitable for the printer of Brother DCP/MFC/HL Series which should work with toner brother tn450 and brother tn 660.