Ughh, my bad. I had CMYK in my head, and the toner/drums go in KCMY.
End result is the same though, the drum you moved from R1 to R3 is bad and needs to be replaced.
My xerox 7845i is making 4 black dots at the end of every pages... What can I do to fix this ? I already try to clean the printhead and to pull out and reset the drum cartrige...
Thanks in advance and sorry for my poor English.