I am still having the problem after several month, except, my printer goes off line for no apparant reason. If I leave it alone it will eventually come back on line and print whatever is in the que. It may take five minutes or several hours but it reconnects to my Wifi and prints. Cutting the printer off and on does not help. All of my computers and other devices are still on line when the printer drops off, so it is not my router or modem.
I did move the printer to a different place in the room and it seemed to reduce the number of times it drops off. (My printer is two rooms away from my router.) I read somewhere that other signals could knock it off line (other devices, microwave ovens, flourescent lights, etc.) but it dropped off line last night when there was no activity in my house.
My next move is to move it near the router, which is very inconvenient and defeats the idea of wireless.