I now have three Xerox Docuprint m750 printers that have failed in the same manner. They fail to print ink on some strokes in "Draft", "Express" and "Normal" modes, but will fill the page with good color & Black when in "best", except it takes about two minutes to printout a page of text !
Does anybody know how to get a service manual otr a service tech. who can fix these machines. I'm convinced (by tests) that it is a system electronics failure, not the print-heads or the ink cartridges.