I’ve set up my Brother MFC-7820N ages ago to print and scan over the network from Kubuntu. Once in a while the router decides to change the IPs of my network devices. So just as a note to myself, here’s how to set up the scanner again:

• check the setup: brsaneconfig2 -q
• delete the old entry: brsaneconfig2 -r MFC-7820N
• determine new IP (as an exercise for the reader)
• set up new entry: brsaneconfig2 -a name=MFC-7820N model=MFC-7820N ip=192.168.1.35

See also Brother’s guide.