Please follow the steps below to solve the problem:

The Brother machine has separate consumables the toner cartridge and the drum unit. Verify you replace only the drum unit and not the toner cartridge. If you want to know their difference, refer to "What is the difference between the toner cartridge and the drum unit?"

NOTE: Illustrations shown below are from representative product and may differ from your Brother machine.

1. Make sure that the machine is turned on.
2. Open the front cover and leave the machine turned on for 10 minutes to cool down.

    

   

    

   After you have just used the machine, some internal parts of the machine will be extremely hot. When you open the front or back cover (back output tray) of the machine, DO NOT touch the shaded parts shown in the illustration. If you do this, you may burn yourself.

    

   

    

    

    

3. Take out the drum unit and toner cartridge assembly.
    
   
    
4. Push down the green lock lever and take the toner cartridge out of the drum unit.

   

    

   • To prevent damage to the machine from static electricity, DO NOT touch the electrodes shown in the illustration.
     
   • Handle the toner cartridge carefully. If toner scatters on your hands or clothes, immediately wipe or wash it off with cold water.
   • We recommend that you place the drum unit and/or the toner cartridge on a clean, flat surface with a sheet of disposable paper or cloth underneath it in case you accidentally spill or scatter toner.
   • To avoid print quality problems, DO NOT touch the shaded parts shown in the illustrations.

     

    

    

   • Be sure to seal up the used drum unit tightly in a bag so that toner powder does not spill out of the unit.
   • Go to http://www.brother.com/original/index.html for instructions on how to return your used consumable items to the Brother collection program. If you choose not to return your used consumable, please discard the used consumable according to local regulations, keeping it separate from domestic waste. If you have questions, call your local waste disposal office.

5. Unpack the new drum unit.
    

   • To avoid print quality problems, DO NOT touch the shaded parts shown in the illustrations.
     
   • Wait to unpack the new drum unit until immediately before you put it in the machine. Exposure to direct sunlight or room light may damage the drum unit.

    

    

6. Put the toner cartridge firmly into the new drum unit until you hear it lock into place. If you put the cartridge in properly, the green lock lever will lift automatically.

   

   Make sure that you put in the toner cartridge properly or it may separate from the drum unit.

7. Clean the corona wire of the drum unit by gently sliding the green tab from left to right and right to left several times.

   

   Be sure to return the green tab to the home position (1). If you do not, printed pages may have a vertical stripe.

8. Put the new drum unit and toner cartridge assembly in the machine.
   DO NOT close the front cover yet.

   

    

9. Press Clear to reset the drum counter before closing the front cover.

   Please reset the drum counter only when you replace the drum unit with a new one.

    

   For models with FAX functions:
   To confirm you are installing a new drum unit, press 1.
   
   For models without FAX functions:
   To confirm you are installing a new drum unit, press the Up Arrow Key.

    

10. When the LCD shows Accepted, close the front cover.