Fixing Vertical Lines on a Scanner

My Epson Perfection 1640SU scanner recently started behaving slightly less than perfectly… I had a pronounced light vertical line appearing down the length of each scanned image.

Really annoying.

Here’s how I diagnosed and fixed it…

Firstly I just tried power cycling the thing, hoping it maybe was some kind of glitch cured by the standard fix.  No joy.

A quick Google brought up no immediate suggestions, but the overall consensus was that vertical lines like this are either caused by bad pixels on the CCD or a fault in the calibration.

Faulty pixels seemed unlikely to me – the line down the pages that were being scanned was a couple of millimetres wide, and detail was visible within it, but everything was just a lot lighter.

I figured it was therefore calibration that was the issue.  From the little I’d read from Googling the issue, it appears that the scanner does some kind of “white balance” before each scan.  Maybe there was dirt on wherever the scanner CCD was calibrating?

Getting into my scanner was easy – disconnect the mains (of course), three screws on the back, two at the front and the top pops off reasonably easily.  Looking underneath the top, I could see that the glass extended a little under the case, at the top, where the CCD normally sits when it’s not scanning.  There was a piece of white plastic or card under the glass (not visible from the outside) where presumably the CCD did its white balance calibration before each scan.

And lo, and behold, there was a little blob of dirt, which looked exactly lined up with the vertical line on the output.  Quite how it got there was anybody’s guess, as it was sandwiched between the white plastic and the glass.  And the glass is glued into place.  Maybe it was always there and just recently shifted.  My theory was that scanner was calibrating itself, and the CCD’s exposure was bumped up on that section because the dirt was making it think that that section was underexposing.

So as the glass was glued in place, I figured my best bet was simply to stick a white strip of paper along the top of the glass where the CCD comes to rest, obscuring that pesky piece of dirt. Worth a try, I thought.

Problem solved.  Reassembled the scanner, no vertical lines at all any more.

Alternatively, if all else fails, this is a good, inexpensive scanner to replace your faulty one:

55 Replies to “Fixing Vertical Lines on a Scanner”

  1. Victory! I managed to gently clean the internal mirrors with lens cloths (wipe with one damp, then with one dry). My scanner’s now working like new. Phew! Thanks for the advice, and apologies for my stress-postings.

  2. Hi there!

    I’m having a similar problem which is really annoying:(
    I have an Epson V37 Perfection (https://www.epson.co.uk/products/scanners/consumer-scanners/perfection-v37) an am an Illustrator, so I frequently need to scan in artwork.

    Is there a method to fix this annoying problem for this scanner? I can’t seem to find any screws at the back of the scanner to open it up, only by the hinges.
    If anyone has a fix for this, please do let me know!
    Regards,
    Rik

  3. I’m having the same problem. I opened up the top and yep – piece of dust between the glass and calibration strip right in the place I’m getting a light strip when I scan.

    I tried putting a piece of paper over the CCD, but I heard a knocking and crunching. Opened up the scanner and the paper was crumpled. How did you apply the paper?

  4. Hey Leslie, I just used a thin piece of paper and some double-backed sticky tape. If your scan head is too close maybe something like Tippex might be an alternative?

  5. Following up on this. I ended up ordering a new Upper Housing Assembly (the part that holds the glass). It cost me less than $50.00 and did the trick.

    I thought about using some double-backed tape, but you know, it’s really hard to find paper that is the same white as the calibration strip. Since I use my scans professionally to create graphics to sell, I decided it was important enough to order the new part.

    This solved my problem. You saved me almost $900! I was all set to buy a new scanner when I decided to do some research first and found your post. Big thanks!

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