I have an Epson Stylus NX635 (listed compatible Air printer) which is connected to my apple airport extreme. The Airport is a base station for my iMac. I also have an iphone 4s and ipad and these can not find my network printer.
AirPrint only works with a Wi-Fi network connection to an AirPrint-capable printer. A printer connected using Bluetooth or to the USB port of a Mac, PC, AirPort Base Station, or Time Capsule is not supported.