I'm wondering if there is a way to print using only 1 of the 2 print heads (A & B) on our XR-640. We've got a bad head (B) and are working on budgets to get it replaced, but it would be really awesome if we could limp along on 1 head for the time being. We can do this on our Epson S80600. I've scoured the interwebs, but I am not finding this info. Can anyone help?