we have a lexmark c540n laser printer. have had it for a few years now.

this morning it started printing lighter than usual. the black toner cartridge was changed but no change in the printing.

recent history: yellow toner cartridge was changed yesterday and waste toner bottle was changed 2 weeks ago.

i printed a test page and the microsoft "windows" were not printing their correct colors (red one was yellow). i also printed a document that has black and red characters and noticed the red were printing mostly yellow. i changed the magenta toner cartridge.

so now we have new black, magenta and yellow toner cartridges but printing is still faint and colors are not correct.

i see no way to "clean" the way inkjets clean their nozzles. i'm at a loss how to proceed.

any suggestions?

thanks in advance.