After upgrading from Fedora 28 the scanner was not working anymore. Here some hints to fix this:
1. Download the Driver Install Tool from the Brother Support Webpage
2. Run the install script
linux-brprinter-installer-2.2.sh
(in my case I specified a Device URI and entered the IP adress)
3. Install libnsl by running
dnf install libnsl
4. The scanner should now work. You can check this by running
scanimage -L
. It should be listed