Sending faxes by placing originals one by one, or by placing originals by size in the ADF, you can send them as one document at their original sizes of A4 or A5 size.
If you place a mix of different-sized originals in the ADF, the originals are sent at the width of the widest sheet among them and the length of each original.
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 Continuous Scan(ADF) to set this to On.
You can also make settings such as the resolution and the sending method as necessary.
Tap 
(Send).
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, set the next originals, and then select Start Scanning.
If you leave the printer untouched for the time set in Wait Time for Next Original after you have been prompted to set the next originals, the printer stops storing and starts sending the document.