I have a Lexmark XS463de mono laser printer. It has been having print quality issues with prints appearing dirty. I removed the cartridge and cleaned the drum which was pretty dirty. Put it back in and no improvement. I remove the drum and clean it again and no improvement. It seems to get soiled immediately. Also, when I fit the cartridge into the drum mechanism the 4 round wheels don't fully seat into the drum mechanism though there doesn't seem to be any way to mate them more closely and the printer seems to work fine otherwise. If the cartridge wasn't seated properly with the drum I don't think it would print at all. Any thoughts? Thanks.