Dell Computer is one of the first to offer Ubuntu as an alternative OS on their machines. So when I updated to Ubuntu, printer computability was the last thing on my mind. If you have Dell A940 (All In One) printer, chances are it will be very hard to get it working with Ubuntu. For me it proved to be impossible. It would be wise to partition your machine and keep your Windows on it in case you will need to work with Dell A940.
This is the first ever frustration I have experienced with Ubuntu- and it is still my preferred OS.