Here are 2 things that may resolve the problem.
First, as only AirPrint fails, try setting the iPhone/iPad's proxy to Auto, as shown here.
Go to settings on your iPad. Select wifi. Press the blue arrow next to the network name in the list your printer is currently on. When the network settings page comes up, make sure the http proxy setting is set to auto. This solved the same issue I had with the 8600 printer. Hope this helps!
If you use a Mac, go to System Settings > Network > WiFi
If that does not work, try resetting the printer to factory defaults, as shown here.
Performing a reset
Follow these steps to perform a reset of the product.
- Press the Power button ( ) to turn on the product.
- With the product turned on, disconnect the power cord from the rear of the product.
- Unplug the power cord from the wall outlet.
Wait at least 15 seconds.
- Plug the power cord back into the wall outlet.
- Reconnect the power cord to the rear of the product.
- If the product does not turn on by itself, press the Power button ( ) to turn it on.