Brother Printer Black Smudges On Paper are mostly caused by foreign materials sticking to the drum of the machine. These could be stapled clips, paper dust, dry glue particles from labels or envelops that severely interfere with the quality of print when you want it the best. Brother Printer Leaving Black Marks On Edge Of Paper typically happens when your printer toner builds up or sticks to these areas on the printer drum resulting in these black dots on the pages that you print.