Cleaning the Scanning Glass and the Rollers
If scanned images contain streaks, or if the scanned documents become dirty, the scanning glass or rollers inside the scanner may be dirty. Clean them periodically.
Open the feed tray.
Open the feeder cover.
Use compressed air to remove dust and paper particles from the inside of the scanner.
Remove any dirt from the scanning glass, separation pad and rollers inside the scanner (parts 
shown in the figure).
Use a clean dry cloth to wipe off any dirt on the scanning glass.
Wipe off any dirt on the rollers with a cloth that has been dampened with water, and then wipe the rollers with a clean soft dry cloth.
Without needlessly rotating the roller, clean the exposed area.
Do not spray water or neutral detergent directly on the scanner. Precision mechanisms, such as the light source, may get wet, and cause a malfunction.
Scratches on the sensor glass may cause marks on the images, as well as feeding errors. If there are scratches on the sensor glass, contact your local authorized Canon dealer or service representative.
