With iX1600/iX1500/iX1400/iX1300/iX500/S1300i, which support Automatic Document Feeder (ADF), you can load multiple documents in the ADF paper chute (cover) and scan them together.
If the paper weight is about the same as standard copy paper (80g/m2 [20 lb]), you can load up to the following number of sheets.
iX1600/iX500/iX1400/iX500: 50 sheets
iX1300: 20 sheets
S1300i: 10 sheets
To scan more documents than the amount that can be loaded on the ADF paper chute (cover), divide the documents into multiple batches and scan them so that the scanned images are combined into a single multi-page image.
For details:
ScanSnap Help
(Select the model name of the ScanSnap at the top of the page)