Brother mfc9460 how do I remove a horizontal blue line on paper

Most lines will either come from laser cartridges, or and most likly the fuser. If you can see the fuser rollers, see if they have wear marks. If so fuser or rollers need replacing. If a multifunction copier with a top glass check the what is called slit glass(small glass where paper goes over when fed from the document feeder.

More likely than not, it's either the imaging drum or the toner causing these lines, and not left over toner on the rollers. Try replacing the toner and see if that works, if not, put the old toner back in and try replacing the imaging drum

toner drum is faulty replace it

Hello. Your cartridge, probably, just needs cleaning. Remove the cartridges from the printer. Take a warm, damp paper
towel. Set one ink cartridge on
the paper towel like how it is
placed in the printer - nozzles
facing down. Drag the cartridge
lightly across the paper towel in
one direction (left to right)
until the bottom of the cartridge
looks clean. Do the same thing to
the other cartridge. Place them back in the printer. If problem persists, try to check this link to the Lexmark website. http://bit.ly/a8KP8M . It gives you another way of cleaning the cartridge nozzles. Hope these resolves the problem. Good luck!

This is an indication the scanner is dirty. Try cleaning the scanner. There are products that have cleaner in them where you simply have to send the treated paper through the scanner.

try moving the small blue slider on top of the drum cartridge side to side 10 times.

on the drum unit that you put your toner inn, There is a blue or green slide lever move the slide back and fourth 10-15 times. If you have some van air blow that area out ( F.Y.I. if you do this some toner will fly out ) if this does not take care of it the drum unit my be bad,

do a 1/2 print test. copier something with a lot of print. open front cover when the paper is 1/2 way through the machine remove drum. Look art the paper and the green drum if the marks are on the paper & drum then the drum is bad. If not the fuser asm is bad, the part that gits hot when melting the toner on the paper,

Hold the rear cover so that the top is horizontal and the rear is vertical. Line it up with the hole in the back and push straight in.

In Lexmark printers the ink cartridges can get clogged sometimes. Re-cleaning the nozzles might help fix your problem. Make sure your ink cartridge is not getting empty.
Hope this helps.

If you are using non brother toner then that's the problem, if not it is the drum unit.