4 Use a commercially available cotton swab to gently wipe dirt off of the sensor glass.
There are two sensor glass areas, one on each side. Use a cotton swab to wipe dirt from the entire surface of each.
Sensor Glass
IMPORTANT
Scratches on the sensor glass may cause marks on the images and could cause feeding errors. If there are scratches on the sensor glass, contact your local authorized Canon dealer or service representative.
5 Gently close the reading unit until it clicks into place.
6 Gently close the maintenance cover until it clicks into place.
48Regular Maintenance