I have a i550 printer which is not printing from the black cartridge.
I know about the "fix" of selecting a different media type and I know that is not an answer - the printer uses the 3 colour cartridges to mix black!
If I try to print a test page with only black text on it and try to print it, the print head does not scan across the page - the paper just runs straight through.
I assume from this that the commands to print in black are not getting through to the printer.
Have you come across this? If so, what do you recommend?