Brother MFC-L5915DW prints faded, streaked, banded or with missing colors

The checks in more detail

If the toner is not low, take the toner and drum out together and rock the cartridge gently from side to side to spread the powder, then put it back. Do this over paper in case any spills. Check that the toner is seated and that the orange protective parts have been removed from a new cartridge. Vertical streaks and thin lines usually point to the corona wire inside the drum unit. A dirty wire causes a line that runs down the page. Brother puts a cleaning tab on the drum unit:

with the printer off and the drum out, slide the green tab back and forth several times and return it to its home position, which is a step the user guide describes. A streak that stays after cleaning may be a worn drum or a damaged roller, and replacing the drum unit is the cure. Also look at the scanner glass if the streak appears only on copies and not on prints, because dirt there produces the same line. If the page is faded evenly, check the print settings: Toner Save mode lightens print on purpose, and it is in the driver's advanced settings and in the printer's menu.

Check the paper type setting, because thick paper set as plain will fuse badly and fade. Damp paper also prints poorly, so use a fresh ream. Run the printer's built-in print quality check page and look at the pattern. Brother's drum counter reset is done only after a new drum is fitted. Use genuine or quality toner, since refilled cartridges can leak and streak. If problems continue after a fresh toner and a cleaned drum, contact Brother with the serial number, as the fuser or the laser unit may need service.