My printer started printing everything too light so I purchased new toner cartridges and replaced them, however that did not fix the problem.  I checked setting in printing preferences based on another suggestion in the forum about this issue and everything is correct.  Drivers are up to date. I've unplugged and plugged back in.  I've used the cleaning rod per the instruction manual.  The manual does not provide any further cleaning instructions.  What is the next step?