We have a Lexmark T620 that we use as our main B&W printer. We were having an issue where when we printed our letterhead our logo would come out missing almost all of the black in our logo (logo is all black with white words). We replaced the toner and now we have almost all the black back but on each print it leaves white spots in the black area. I think it may be the drum but not sure.
I'm a complete dope when it comes to printers, I'm used to having support and maintenance contracts and not having to worry.