How to solve vertical lines in scanned documents on Brother MFC 9330CDW

Written by Claudio Kuenzler - 0 comments

Published on August 24th 2021 - Listed in Hardware

For the last couple of weeks I came across a very annoying problem: Whenever I scanned (or copied) a document using the ADF (Automatic Document Feeder) on my Brother MFC 9330 CDW, vertical lines showed up in the scanned document (or the copy)!

Although I braced myself for some heavy maintenance work including screwdrivers, the solution was surprisingly easy. But let's start at the beginning.

Vertical lines in the output

First I created a simple A4 paper, which I would then use as original for scanning tests. Now this piece of paper is placed into the ADF and scanned (into a network share):

Original paper for Brother MFC 9330 CDW scan tests

The result contains these mentioned vertical lines:

Clean it, duh!

On my research why this actually happens, an official video from Brother turned up. In this video Brother simply suggest to clean the scanning glass. I really did not think this would do the job, but the video mentions something important:

Run your finger along the glass strip and check for debris. If debris is found, concentrate cleaning on that area.

I did so. And I felt something at the top (towards the rear) of the glass strip. I would not have called this "debris" but rather some dirt stuck on the glass. However by just visually looking at the glass, everything seemed to be clean.