Scanner streaks only on ADF — CIS line contamination fix
Joe B.
Reviewed for technical accuracy
Specialities: ADF/CIS scanners, narrow glass cleaning, calibration (shading), rollers & separator pads, HP/Brother/Canon/Epson/Lexmark
Vertical streaks from ADF only — clean CIS slit glass, narrow scanner glass, rollers/separator; shading calibration & scratch test
Technician
• Do lines appear only from the Automatic Document Feeder and not from the flatbed?
• Are the streaks thin grey/black lines in the same spot every page, or random bands?
• Brand/model and whether it’s a CIS or CCD scanner (most home/office MFPs are CIS).
• When was the last time the narrow slit glass and white calibration strip were cleaned?
Technician
Plan: 1) Clean narrow/slit glass + white reference strip. 2) Wipe ADF pickup/feed/exit rollers & separator. 3) Run shading calibration. 4) If a scratch exists, do a quick tape test and consider replacing the slit-glass.
Technician
• Lift the ADF; next to the main glass there’s a narrow strip of glass (the ADF/CIS window). That’s where the streaks start.
• Power off. Use a lint-free cloth slightly dampened with isopropyl alcohol (or approved glass cleaner). Wipe the entire slit glass edge-to-edge; then clean the white calibration strip on the ADF underside.
• Inspect under bright light for tiny dots, adhesive, or White-Out. Even a pin-speck causes a full-length line.
SEO notes woven in: clean ADF glass, remove vertical lines on scans, fix streaks on copies, narrow glass cleaning.
Technician
• Open the ADF path. Clean the pickup/feed/exit rollers and separator pad with alcohol. Toner dust on rollers re-contaminates the slit glass.
• If your model has ADF maintenance or scanner calibration (shading) in settings, run it now so the CIS black/white reference is rebuilt.
• Feed a blank sheet through ADF and check if the streak is still in exactly the same place → that means remaining debris or a micro-scratch.
Technician
• Shine a phone flashlight across the narrow glass at a low angle. A scratch shows as a thin groove you can’t wipe away.
• Tape test: place a tiny strip of clear tape over the exact spot (no bubbles), scan a blank page. If the line disappears or changes character, you’ve masked a scratch. Replace the slit-glass assembly when convenient.
• On DADF/RADF units, repeat for both scan paths.
Technician
• Use a maintenance sheet monthly: wipe slit glass + white strip + rollers.
• Avoid feeding pages with wet correction fluid, labels, or stapled edges — they leave adhesive/ink that creates vertical streaks.
• If your printer supports it, set a reminder for ADF cleaning after N pages.
Technician
• Duplex (DADF/RADF) one-sided lines: each side has its own slit glass/path. Clean both windows and both white strips.
• If banding moves between scans, it’s not CIS contamination — check driver settings or try another app to rule out software artifacts.
Technician
Quick answer: the accepted fix
Accepted fix when ADF scans show vertical streaks: thoroughly clean the CIS slit/narrow glass and white reference strip, wipe ADF rollers and separator pad with isopropyl alcohol, then run scanner calibration/shading. If a scratch is found, use a temporary tape mask and plan to replace the slit-glass.
Why streaks happen on ADF (CIS slit glass, debris & adhesive)
With CIS scanners, a tiny speck on the narrow glass stays in the sensor’s view while paper moves, so the mark becomes a full-length vertical line. Common sources: toner dust, label adhesive, dried correction fluid, roller transfer. Cleaning the slit glass, white strip, and rollers removes the artifact and prevents re-contamination.
How to verify the fix
Scan a blank page via ADF and via flatbed. If the line appears only from ADF and in the exact same position, the slit glass or white strip still has residue or a scratch. After cleaning, run the device’s scanner calibration/shading to rebuild reference values.
ADF streaks — quick troubleshooting tips
Most ADF-only lines come from CIS slit-glass debris or roller residue.
Quick path: clean narrow glass + white strip → wipe rollers & separator → run shading calibration → scratch tape test if the line persists. This resolves the majority of ADF vertical streaks across HP/Brother/Canon/Epson/Lexmark.
Disclaimer: This information is AI-generated and intended for general guidance only. For advice specific to your environment, please consult a verified expert on Whizz-Tech before making decisions.
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FAQ
Why do streaks appear only from the ADF, not the flatbed?
ADF uses a CIS slit glass. Debris on this narrow glass stays in the sensor’s view while paper moves, drawing a full-length vertical line. Cleaning the slit glass and the white calibration strip fixes it.
What should I use to clean the narrow glass and rollers?
A lint-free cloth with isopropyl alcohol or approved glass cleaner. Wipe the slit glass, white strip, and pickup/feed/exit rollers & separator pad. Avoid paper towels that shed fibers.
How do I know if the slit glass is scratched?
After cleaning, if a thin line remains at the same position, inspect with angled light. Use a clear tape test: if the line changes, you’ve masked a scratch — plan to replace the slit-glass.
Do duplex ADFs (DADF/RADF) need extra cleaning?
Yes. Duplex paths can have two slit glass windows and two white strips. Clean both sides and run scanner calibration/shading.
Sources
- HP — Vertical lines or streaks when copying or scanning from the ADF
- Brother — Vertical lines or streaks on copies, faxes, and scans (clean ADF scanner glass)
- Canon — Clean the ADF (Auto Document Feeder)
Filed under: Print quality & color
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