Have a PHASER 850 that prints with the center of the page wiped out. In other words, only the left and right hand edges have print on them. I ran the eliminate light stripes process a few times and it started printing normally. The next day I tried to print again and it was back like before with the center missing. I cannot find any thing in the paper path that might be wiping the print from the page and so suspect a bad printhead. Any other ideas?