Automatic feed gives a white line in copy or scan

There is something on your scan glass. My guess is you are getting the line on your copies when you run the original through the document feeder. If you get lines through the document feeder but not on copies made off the glass then it is a dirty scan glass. There is a thin glass strip where the document feeder feeds the original. Usually something like white out that did not dry smears off an original and ends up on this thin strip of glass. Scratch it off with your finger nail and use some glass cleaner to resolve the problem. The scan glass is about 1/2 an inch to an inch wide and will be on the same side of the machine that the copier feeds the originals in on.

There is something on your scan glass. If you get lines through the document feeder but not on copies made off the glass then it is a dirty scan glass. There is a thin glass strip where the document feeder feeds the original. Usually something like white out that did not dry smears off an original and ends up on this thin strip of glass. Scratch it off with your finger nail and use some glass cleaner to resolve the problem. The scan glass is about 1/2 an inch to an inch wide and will be on the same side of the machine that the copier feeds the originals in on. Once the glass is clean your problem is solved!

If the problem only happens on copies or sent faxes then no it is not your drum. There is something on your scan glass. My guess is you are getting the line on your copies when you run the original through the document feeder. If you get lines through the document feeder but not on copies made off the glass then it is a dirty scan glass. There is a thin glass strip where the document feeder feeds the original. Usually something like white out that did not dry smears off an original and ends up on this thin strip of glass. Scratch it off with your finger nail and use some glass cleaner to resolve the problem. The scan glass is about 1/2 an inch to an inch wide and will be on the same side of the machine that the copier feeds the originals in on

You need to clean small exposure glass located on the left of the main exposure glass.If this doesn't help,it can be a dust under the glass or on the mirrors that causing lines.

I have the exact same problem. It was there since I first bought the MFC-7840W.
Vertical line appears in scans using the automatic document feeder (ADF).
Vertical line does not appear when scanning single page (placing it directly on the glass -- i.e. not using the ADF).
Cleaning the glass strip for the ADF (or the white pressure bar overhead) does not solve the problem.
The problem does not occur with copies using the ADF (using the COPY button which is basically a scan and print). This would suggest that dust and dirt is not to blame because that would also appear on the copies.
But since I believe a copy is basically a scan plus print, they should be using the same electronics -- a hardware problem on the scan would likely appear on a copy also -- there is some difference between how they accomplish this.
It's definitely not a software issue since it occurs on all versions of Windows and Mac OS X (and multiple computers). It also does not matter whether I "push" the scan to the computer by using the scan button on the MFC... or "pull" the scan from the MFC using the Brother Control Center software.

BLANK or BLACK?, if it's Black, clean the SCANNER GLASS.

If the lines are vertical (in the direction the ADF feeds, 11in long for 8 1/2 by 11) You can try cleaning the glass the scanner uses when it's using the document feeder. Pull up the top left part of the printer where the documents feed, there's a little rib in the middle of the side to help you do this, then simply pull up the assembly underneath with all the rollers in it, you should see about an inch of glass underneath and a centimeter long strip of white plastic on the assembly (this serves as the white background when feeding slimmer papers) Clean them both. I'd recomend any glass cleaner, just don't spray it in there, spray it onto a cloth.

The problem is that that there a small piece of glass that the doc feeder use's to scan the orginal. You will have to clean the small glass it's about a half of a inch piece and is normally under the doc feeder unit. It will either be to the right side of the main copy board glass or it is under the doc feed unit where the paper goes down through the feeder. It is mostly some white out on the glass, just clean with a dam cloth with water or windex..... Good Luck

you don't mention whether the document you are copying also appears on the paper.If it does you could have 1 of 2 problems-
The drum cleaning system could be at fault or-
the fuser roller has picked up some **** easy test...... run copies and when the 1st copy edge appears switch OFF. This is a crash stop.Now examine the sheets in there.Is the stripe on the copy before the fuser (Heat) roller? If yes you could have a drum cleaning problem, usually fixed by changing the drum module.If no and the stripe appears after the heat roll, the problem is with the fuser system,dirty rolls etc. There are a number of other problems with stripes, but you have to start somewhere! If the document does NOT appear on the copy, forget all above, could be scan or ROS problem

If the lines only appear when using the top feeder, then theres probably white-out or something on the thin strip (called a slit glass) of glass on the left of the large glass.

If it appears when you put a document on the large glass, then it is another problem.