When scanning/copying from the document feeder, scanes often have blank strip all the way down the center of the page

When copying from the feeder the page is fed across a fixed point at the head of the flatbed. Any dirt etc on the glass at this point can present as a dark line running vertically down the printed page. When copying from the flatbed, the scan head is moved down the page so any dirt on the glass will only appear as specs. Try cleaning the glass, especially at the head of the flatbed where the feeder is loading the page to be copied.

Check your flat bed and Document feeder scanning glass need to be clean, if any dot or dust in scanning glass of document feeder it will appear a line, check this points first
1- Check printouts from computer or FAX if it is clean problem in scanning section
2- Check using Copying a blank paper using only Flatbed if it prints without any line its problem from document feeder Scanning glass
So solution is clean the Document feeder scanning glass using wet cloth, note careful about wet cloth switch off the machine and clean it

Clean the scanner strip glass. This is the thinner strip of glass that runs from front to back right next to the large glass. This glass is only used when scanning/copying using the document feeder. The line you are seeing is because something has become stuck to the glass so when the documents are fed over the strip of glass, the scanner reads the stationary spot of debris as a solid line. Clean the glass very well using a cloth and some glass cleaner. I have seen something get under the glass as well but this is very rare. Rest assured tho that the line is being caused by something on this strip of glass.
Good Luck and Thank You for using Fixya.
WheatlandServices

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.

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 have white out or some other white substance blocking your scanner optics. I am assuming this is a thin blank line. What you need to do is make a copy of a document with your machine. You should see the very same blank line on your copy that your customer is seeing on their received fax. Now take this copy and place it in the document feeder the same way you placed the document when you made your copy. Now imagine this document going thru the feeder. The strip that is blank will "match up" with the white out or whatever is causing the blank line. You just need to open up the feeder section where the documents go in to be scanned and look for the thin strip of glass that runs from one side to the other. Using the copy you made with the blank line, use it to see exactly where the glass should have something stuck to it and clean it off with a soft clotch with a little glass cleaner on it. Go ahead and clean the while glass while you are in there. Once clean you can close it back up and run another copy to insure that all the lines are gone.
Good Luck and Thank You for using Fixya.

The most common cause of blank (void) lines on a scanned document is from whiteout on the glass where the page is scanned when using the document feeder.
If there is a clear mylar sheet on the bottom of the document feeder, the whiteout may be there instead.

If there was dirt or a dark smudge on the glass (or mylar), it would show up as a black line, but whiteout is white, and shows up as a void (blank) line.

You need to clean the scanner glass. Also known as the strip glass. It is a 1 inch wide strip of glass that runs from the front to the back. Your documents pass over this glass when they are scanned. Some of the wax crayon probably smeared off onto the glass and now when you scan the scanner sees these marks as stationary and thus records them as solid lines. Just look into the scanner section where your documents are fed in or depending on model, some are just to the left of the large original glass.
Good Luck and thank you for using Fixya.

If you open to document feeder and look at the glass when scanning via flatbed, just to the left will be a smaller piece of glass. That is the glass used when scanning through the feeder. Clean that glass as there is probably a couple of spots on it.

There is a small strip of glass under the feeder.Not the main glass, but look where the lamp is sittting in the start position.
You have something on that section of glass.
It may be very tiny, but that is what causes that. Best way I have found to get that clean is with some alcohol and just a plain piece of copy paper crumpled and used as your cleaning towel.
The reason it is there only when you copy through the feeder is this. When you copy off the glass, the lamp moves and scans the original end to end. So a spot is simply a spot.
When you run through the feeder, the lamp parks and the document passes over the lamp scanning that way. So any mark between the lamp and document will repeat and be line down the page.