Fujitsu Fi-5110EOX2 - ScanSnap! - Document Scanner Operator's Manual page 54

HINT
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If you use the stacker, scanned document sheets will not be separated when
they have passed through the scanner. For details on how to attach the stacker
to the scanner, refer to "Names and Functions of Parts" on page 3.
Use the stacker as follows.
1. Pull out the stacker towards you while holding it by its handle.
Handle
2. Insert your finger into the indent and lift up the stacker extension to clap it
out.
Stacker
Indent