I have a Epson Workforce 545 that has printed via airprint before, but now get a message that "can't find printer".
Have you tried to turn the printer on and off? Or, have you tried a restart or a reset of your iPad? To do (apologies if you know how):
Restart: Hold down the power button until the power off slider appears. Slide it off. When the iPad finishes shutting down, hold down the power button again until the Apple logo appears.
If that doesn't help, try this step...
Reset: Hold both the power and home buttons until the screen goes dark and the Apple logo then appears (the slide to unlock screen may or may not appear). Once the logo appears, release the buttons. After a time, your homescreen will appear. Please note that it may take some time for the Apple logo to appear or for your homescreen to appear (or both). This is normal. Eventually, the homescreen will appear.
Sometimes, the iPad just needs a swift kick in the software to get it to work as it did before. So, try this?
Good luck and let us know how you get on.
Marilyn