Air printing from my ipad was fine until today

hi!

this is from apple on airprint:

Additional Information

If you are unable to print, or if you see the message "No AirPrint Printers Found"

Verify that the printer:

1. Has power and is turned on. If it has power, turn the printer off and then on again to see if that resolves the issue.
2. Is connected to the same Wi-Fi network as the iOS device.
3. Has the latest firmware version installed.
4. Has paper with enough ink or toner installed.
5. Is free of any errors displayed on the printer's control panel.

If necessary, consult the printer documentation or contact the printer vendor for help with the above steps.Notes:

• Avoid connecting AirPrint-capable printers to the USB port of Apple AirPort Base Stations or Time Capsules. Doing so can enable traditional AirPort printing from a Mac, but it will not enable AirPrint functions for iOS devices. If you cannot use Wi-Fi networking to connect the AirPrint-capable printer, use an Ethernet connection from the AirPrint-capable printer to the Apple AirPort Base Station or Time Capsule.
• Wi-Fi printers can take several minutes to join a Wi-Fi network after being turned on. Ensure that the printer is connected to the Wi-Fi network before attempting to print.

failing that you could try and app like print n share which will let you print from pages and keynotes etc or the hp eprint app

also contact hp support if you can/post on the hp forum as well