Dell 2155cn/cdn Color Laser Printer - Manual (Page 642)

640 Maintaining Your Printer
8 Insert the standard 250-sheet tray into the printer, and push until it stops.
Cleaning the Scanner
Keeping the scanner clean helps ensure the best possible copies. It is
recommended to clean the scanner at the start of each day and during the day, as
needed.
1 Slightly dampen a soft lint-free cloth or paper towel with water.
2 Open the document cover.