Sending faxes by placing originals one by one, or by placing originals by size, you can send them as one document at their original sizes.
If you place different sized originals in the ADF, all of the originals are sent at the largest size among them. To send originals at their original sizes, do not place originals with mixed sizes.
Place the first batch of originals at the same size.
Select Fax on the home screen.
Specify the recipient.
Select the Fax Settings tab, and then tap ADF Continuous Scan to set this to On.
You can also make settings such as the resolution and the sending method as necessary.
Tap 
(Send) on the Recipient tab.
When scanning the first set of originals is complete and a message is displayed on the control panel asking you to scan the next set of originals, select Yes, set the next originals, and then select Start Scanning.
If you leave the printer untouched for the time set in Settings > General Settings > Fax Settings > Send Settings > Wait Time for Next Original after you have been prompted to set the next originals, the printer stops storing and starts sending the document.