Canon imageFORMULA DR-4010C Reference Manual page 40

Note
The location of the sensor glass and various rollers are shown
below.
Sensor Glasses
2
Use compressed air to keep the interior of the scanner free of dust
and paper particles.
3
Use a clean dry cloth to wipe dirt off the sensor glass.
Wipe both the top and bottom sensor glasses.
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.
36 Maintenance
Roller Unit
Rollers
Retard Roller