I have the Epson R800. I can do basic printing through the Airport Express without any problems, however, I could not install the Epson drivers which allowed me to do borderless printing or use the roll feeder. Also, I could not access the Epson utilities to check ink levels and clean and align the cartridges. Once, I plugged it in directly via USB, all the drivers and the utilities were available.
So, it will probably work, but you won't have full functionality.