So beside the printer I need to use the cable, but in the rest of the house I can use wireless. The Mac beside the printer somehow monopolises or interferes with the signal (like when you have a poor FM reception on the radio, and the sound is clear when you're near the radio, but move to the wrong place and white noise breaks in). I therefore deduce that the wireless receiver in the printer is weaker than in the Mac. When I'm away from my desk, for some reason it does seem to work. When I'm at my desk (printer beside MacBook Pro), the wireless rarely works.
OK, it's a bit bizarre, but I have an idea.
