Hellow rgetter,
Did you find a solution to this problem? We have the same issue. One of our computers loses connection constantly. I called Xerox and explained the situation. The computer in question is a laptop that is brought home every night. The Xerox rep said that's the issue and he couldn't do anything to help.
Problem is, it will lose connection during the day. We'll refresh the network scanner in the morning, scan something, and a couple hours later, that same computer won't be on the Network scan list on the machine.