If the USB port on the printer is used to trasfer printing data between the PC and the printer using a standard cable, then I can't see why the adaptor wouldn't work... However you'd need two bluetooth adaptors so that they could communicate. It might require that your printer natively supports an optional adaptor for it to work, but with a bit of tweaking you could probably bridge the connections anyway... I'd have to think on this :damn:
In the meantime, if you wanted to test if the adaptor was compatible, you could try plugging it into your printer and then do a bluetooth scan on your phone. If the phone picks up the printer, try sending a picture to it and see what happens. I dunno if they still do it, but Sony Ericsson put a HP print program in the 'applications' section of some of their phones. You could try using that and see if it finds the printer. If it can't pick it up, the chances are that the Bluetooth adaptor won't work with the printer. Not natively anyway. If that was the case, you'd have to somehow bridge the connection between that adaptor and another bluetooth adaptor on your PC and effectively 'trick' the PC and printer into thinking they were connected by cable. I'm still not sure about this though...