Install brother-cups-wrapper-mfc9420cn by entering the following commands in the terminal:
sudo apt update sudo apt install brother-cups-wrapper-mfc9420cn
Description:
Cups Wrapper drivers for mfc9420cn brother printers
This package provides all cups wrapper drivers for models
Homepage: http://solutions.brother.com/linux/en_us/
Version: 1.0.0-1-0ubuntu7
Section: multiverse/text