Cleaning the Scanning Glass of the Sensing Unit-B 

If the scanning glass becomes dirty, the scanning process cannot be performed correctly, which results in errors.
1
Open the front cover of the "Sensing Unit-B."
2
Raise the handle of the A3 guide and open the guide.
3
Clean the glass section.
Use the supplied glass cleaning sheet to wipe the surface. If you cannot remove the dirt, soak a soft cloth in water, wring it out well, and use it to wipe the surface. Finally, wipe the surface with a dry soft cloth.
Proceed to the next step after the surface have got dry completely.
4
Lower the handle of the A3 guide and close the guide.
If you continue experiencing errors after cleaning the scanning sensor
Contact your local authorized Canon dealer.
5
Lower the handle of the A2 guide and open the guide.
6
Clean the glass section.
Use the supplied glass cleaning sheet to wipe the surface. If you cannot remove the dirt, soak a soft cloth in water, wring it out well, and use it to wipe the surface. Finally, wipe the surface with a dry soft cloth.
Proceed to the next step after the surface have got dry completely.
7
Raise the handle of the A2 guide and close the guide.
If you continue experiencing errors after cleaning the scanning sensor
Contact your local authorized Canon dealer.
8
Close the front cover of the "Sensing Unit-B."
9Y3E-026