Hi and welcome to Just Answer. My name is XXXXX XXXXX have been repairing Electronics Professionally for over 13+ years and currently own a Shop in FL.
The error 4F indicates a bad Print Head. This can also be a purge count issue as well. The following instructions to reset it below have been known to fix this issue if it's not the Print Head:
1. Press the Menu, then Mono Start key then press the UP arrow key 4 times to make the machine enter the maintenance mode and "ERROR 46" pops-up in the display.2. Enter maintenance mode 80: Select 8 by pressing the UP/DOWN arrow key and push OK key and select 0 and push OK key3. Now Press MONO arrow key several times until you see PURGE:XXXXX4. Select 2 and push OK, Select 7 and push OK, 8 and push OK, select 3 and push OK and the purge counter is now reset to 00000.5. Press STOP/EXIT key to go to root of maintenance mode6. Enter code 99 to exit maintenance mode: Select 9 and push OK, Select 9 and push OK.
You have to press these in order fairly quickly without stopping or it wont work.
I've now managed to follow all the instructions but it still has the same error.
Alright, yeah the Print Head is definitely bad in it. I just wanted to be sure by resetting the purge counter first. The Print Head on your model was not deigned to be replaced. The only options you have at this point is if you still have a warranty on it, Brother will replace it for free or you'll need to get a new printer because the cost to repair the Print Head is much more than buying a new one. Hope this helps my friend.