I have an HP F4580 printer, I used to use it with my Pc and it was fine, no problems. I swapped to a Mac, and it picked up the printer wirelessly, again no problem. But if I want to use the scanner, it has to be connected by USB - I've done this but the Mac doesn't seem to recognise the scanner. It doesn't show up anywhere, and when I press the scan button nothing happens. I don't really know where to start - anybody got any ideas?