Scanner Leaving Lines, Streaks, and Marks on Scans

Line and streak defects on scans tend to create a lot of confusion because they can look like software corruption, dirty originals, or random image-processing problems. In practice, these issues often repeat with surprising consistency. A line may appear in exactly the same place on every scan, or a mark may follow the path the paper takes through the scanner rather than anything in the file itself. 

That kind of repeat behavior usually points away from the software side and toward something physical in the glass path or the way documents move through the device.

The examples below focus on scanners and multifunction devices that continued to capture images, but added lines, marks, or streaks that stayed visible across jobs and did not disappear just because the software was reinstalled.

Problem: Thin line appears on every scanned item in the same place

What users observed: On the Ricoh fi-8170, a thin line or surface marking appeared on the same side of every scanned item. This happened even when the originals were sleeved, which made it less likely that the source documents themselves were causing the mark.

What was tried: Compressed air cleaning and extensive scan-setting changes were tried, but the line remained.

How this played out: The line stopped only after low-speed feed mode was enabled. The change did not come from reinstalling software or adjusting image settings. It came from changing how the item moved through the scanner.

Problem: Lines on scanned or copied pages across the same narrow area

What users observed: On the Ricoh IM 550 and related MP-series cases, lines appeared on pages during scanning or copying. The issue affected output quality consistently enough that it pointed to a repeated physical defect rather than a one-off job problem.

What was tried: Users inspected the scanner glass and feeder areas, focusing especially on the narrow glass strip used by the document feeder path.

How this played out: Cleaning the glass surfaces restored normal output. The marks were linked to buildup on the scanner readers rather than to the scan software or driver.

Problem: Marking follows feeder transport 

What users observed: In the Fujitsu fi-8170 case, the same physical marking behavior stayed present despite major changes to scan settings. This made it clear that image-processing options were not changing the defect.

What was tried: Users changed scan settings extensively and cleaned the device, expecting the mark to respond if it were being introduced digitally.

How this played out: The marks only changed when feeder speed changed. That showed the defect was tied to transport and contact conditions during scanning, not to the way the image was being processed afterward.

Problem: Line or streak remains even when scanning software changes

What users observed: In line-related scanner cases, the defect usually stayed in the same place even when the software path or scan configuration changed. That gave the impression that the scanner was “working,” but always contaminating the image the same way.

What was tried: Cleaning attempts, scan option changes, and repeated rescans under different conditions were used to see whether the line would move or disappear.

How this played out: The line only cleared when the physical cause was addressed, such as cleaning the feeder glass strip or altering how the document moved through the scanner. Software changes on their own did not remove the defect.

Problem: The issue affects both scan and copy output, not just one workflow

What users observed: On multifunction Ricoh devices, the same line behavior could appear on copied pages as well as scanned pages. That mattered because it ruled out application-level scan problems and narrowed the issue to the scanner path itself.

What was tried: Users compared copying behavior against scanning behavior and then focused on the physical reader surfaces.

How this played out: Once the relevant glass areas were cleaned, both scan and copy quality returned to normal. The defect did not require software reconfiguration to disappear.