Fujitsu fi-4220C Operator's Manual page 16

Do not use aerosol sprays near the scanner.
Disconnect the power plug from the power outlet when the
scanner is not used for a long period of time.
Do not install the scanner in the direct sunlight.
Be aware of the pick spring.
xiv
Do not use aerosol sprays to clean the scanner. Aerosol sprays cause dirt and dust to
enter the scanner, resulting scanner failure and malfunction.
When the scanner is not used for a long period of time, be sure to disconnect the
power plug from the power outlet for safety.
Do not install the scanner in the direct sunlight or near heating apparatus. Doing so
might cause excessive heat to build up inside the scanner, causing fire or scanner
trouble. Install the scanner in a well-ventilated location.
When you perform cleaning, make sure that the inside of the scanner is free of any
foreign object, and be careful not to get your hand or the cloth caught on the pick
spring (metal part) as a deformed pick spring (metal part) may cause injury.