Lines appear on scanned documents

Symptoms

• Straight lines appear on every scanned page in the same position
• Lines don't appear when printing, only when scanning or copying
• Problem is worse when using the automatic document feeder (ADF) versus the flatbed
• Line position matches a specific spot on the glass

Likely causes

• CommonDust, dirt, or smudges on the scanner glassAny debris on the glass directly under the scan sensor's path appears as a line on every scan.
• CommonDebris on the automatic document feeder's narrow scan glass stripADF scanning uses a thin strip of glass that collects dust and paper debris easily, causing a very consistent line.
• PossibleScratch or damage to the glassA scratch will produce a similar line that cleaning won't remove.
• Less commonDust on the scan sensor itself, out of easy reachInternal dust beyond the glass is less common but possible on older units.

What to do

1. Lift the scanner lid and clean the entire flatbed glass surface with a soft, lint-free cloth, using a little glass cleaner on the cloth (not sprayed directly on the glass).
2. If using the automatic document feeder, open its cover and locate the narrow strip of glass, cleaning it thoroughly since this is the most common source of a consistent line.
3. Run a test scan or copy after cleaning to check if the line has disappeared.
4. Check the same spot on the glass under good light for a scratch, which cleaning won't remove.
5. Try switching between the flatbed and the ADF (if both are available) to confirm whether the line is specific to one method.
6. Clean any felt or white backing strip opposite the ADF glass, since debris there can also cause visible marks.

Tools and parts

• Lint-free cloth
• Glass cleaner

When to call a pro

If a thorough cleaning of both the flatbed and ADF glass doesn't remove the line, a scratch or internal sensor issue is likely, and a technician can assess whether the glass or sensor needs replacement.

Safety