Q: HP Photosmart 5515 - doesn't work airprint

I have a hp photosmart 5515 wich works fine wireless with a windows laptop and a mac mini, but it does not work with the iphone and ipad.

Apperantly everything is right, i've tried all the solutions from apple and hp, but the ipad and iphone can never find the airprint printer.

All the devices are connected to the same wi-fi.... i don't what else to try.

Does anyone know what could be stopping the devices to detect the printer?

Thanks