I have an HP C4280 printer happily printing wirelessly through an AirPort Express from iMac but I can't find it from my iPhone 4S or iPad. All the devices are on the same BT home-hub network. Any ideas?
It does not appear as if the C4280 is AirPrint compatible. Check this Apple support document to verify:
An App like Print Central installed on the iPhone and iPad might allow you to print to the HP printer.
PrintCentral Pro for iPhone/iPod Touch - iTunes - Apple
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