Last week my printer began printing large smudges on the paper. I have ran the following cleaning settings: clean fixing assembly plus reduce back side stain, clean ITB, and clean feeder with no luck on fixing the issue. Please any trouble shooting or repair suggestions!
If cleaning the ITB and fixing assembly did not resolve the issue, it looks like the printer might need service. In this situation, you can also try removing all of the toner cartridges and check the inside of the printer for any loose toner powder that you can wipe up with a damp cloth. Once the inside of the printer has been cleaned, you can try cleaning the fixing assembly and ITB again. If that does not resolve the issue, you can log into your MyCanon account to check your available service options.