If you're using Linux with the CUPS printing system, and you own a Brother MFC-7220 USB multifunction printer / scanner / fax machine, you may find the following information useful.
I'm posting this information here because it seems to be very difficult to find online, and took me months before I solved it. I had bought an MFC-7220 over a year ago (in 2013), and installed the drivers that Brother published on their website. Everything seemed to work well for a while.
However, sometime in late 2013, after upgrading CUPS, the printer drivers stopped working. It just stopped printing, and no matter what I did, nothing would happen. Print jobs get put into the queue and the printer did nothing. I dug in the error logs, searched online, turned on verbose CUPS logging, even dug into the source code, nothing. It was a very frustrating experience. Part of the problem could be related to the fact that the drivers on Brother's website date all the way back to, oh, 2007? ☺ Even if those drivers are currently working for you, you might want to consider a more robust solution, since they don't seem to be updating those drivers anymore, and you might find yourself in a similar situation as CUPS development continues and old APIs cease to be supported.
After a long, frustrating search, I finally found a clue in an obscure post somewhere in the Ubuntu forums, hinting that CUPS actually comes with a driver that works with the MFC-7220. It appears that the printer part of MFC-7220 is identical to Brother's HL-2060 printer; so all I had to do, was to uninstall the MFC-7220 drivers, delete the printer from the CUPS web interface, and then re-add the printer and select the HL-2060 driver for the printer. After this very non-obvious choice of printer driver, the printer started to work perfectly again.
So if you are running Linux (I'm using Debian) and are having trouble with the printer functions of the MFC-7220, try installing it as a HL-2060 instead. It might just be the thing you need. ☺