I have a CP4525 that prints a magenta background on all prints.
I have reseated the formatter (several times) - this seems to fix the fault initially, but after a couple of weeks the problem comes back, again reseat the formatter and hey presto, fault gone again. (for a couple of weeks)
There doesn't seem to be any pattern as to when it starts, the only time I managed to get it to start printing the full magenta background was after running a config page (black/white printing only), then running a PQ troubleshooting print. The next print after the PQ print had the full magenta background. I reseated the formatter and I couldn't reproduce the fault again - all seemed OK !!
Has anyone else seen the issue ? and if so how was it resolved ?