Sometimes this will happen on refurbished cartridges.
You can usually gain some life from your toner carts by using this procedure, but not always.
<Should work on Brother 5340, 5250, 5450 and other models too>
1. Turn Printer OFF and OPEN the toner door
2. Hold the GO button as you turn on the printer until all lights are ON
3. Keep holding the GO button until status light goes OFF
4. Press the GO button 2 times
5. The Paper, Drum & Toner light will come ON
6. Press the GO button 6 times
7. Status light will turn RED
8. Close the front
Good Job! You are now a CPT (Certified Printer Technician)