Scanner stopped working (the scanner isn't available) - how to diagnose properly?

I have a HP 2320fxi that was running perfectly, all of a sudden scanning has stopped working. Printing is still OK. I am running Windows 8.1, connected over network (printer on static IP). Can anyone please advise the proper fault finding routine with scanners? So far I do: Checked i can ping and print to the printer - I can. Checked Windows Image Aquisition (WIA) service is running - it is. Control Panel -> View Scanners and Cameras, I can see the device listed. I click on the properties button, and a warning is displayed The scanner isn't available. Make sure the device is turn on and is con

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