I've owned this printer for nearly 10 years but recently the printouts are coming out smudged, along with the photocopies . What is the cause of this ? I've replaced the toner several times and am currently using a copy toner - not the original samsung branded toner. I think this has now been discontinued. Is it the quality of the toner im using or dust building up inside the printer ? I want to make sure I troubleshoot it as much as i can before i buy another printer.