Hi LeandroA,
The WorkCentre 3335 would need the to have a duplex document feeder to do two sided scanning. From the user guide:
2-Sided Scanning scans both sides of the original document.
Note: 2-Sided Scanning is only available on devices that have a duplex document feeder.
- At the printer control panel, press Clear All , then press Services Home .
- Touch Scan To, then touch and hold the Right Arrow button until Scan To...Features appears.
- Touch 2-Sided Scanning.
- Select an option.
- Touch OK.
If your machines do not have the Duplex Document Feeder then you need to order one or only do one sided scans. Please consider contacting your support centre for further assistance.