Canon Pixma MX520 Series Online Manual page 748

Note
You can save up to 50 pages of fax as one PDF file.
You can save up to 2000 PDF files on a USB flash drive.
Faxes are saved according to the order of the transaction number when Save all documents is
selected.
If the USB flash drive is removed or becomes full while saving faxes is in progress, the error message
is displayed on the LCD. Press the OK button to dismiss the error.
The folder and file name of faxes saved on the USB flash drive is as follows:
Folder name: CANON_SC\FAXDOC\0001
File name (file extension: PDF): Running numbers, starting from FAX_0001
File date: The date and time of saving as set in the machine.
For details on how to set the date and time:
Setting the Date and Time
• Importing Faxes Saved on a USB Flash Drive to the Computer
You can import faxes saved on a USB flash drive to the computer.
After saving faxes, connect the USB flash drive to the computer, then import the data.