By placing originals one by one, or by placing batches of same-sized originals in the ADF, you can send them as one fax document at their original sizes.
If you load a batch of mixed-size originals into the ADF, the originals are sent at the width of the widest original and the length of each original.
Place the first batch of same-sized originals.
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 select 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.