For the Sharp MX-3070N, 2-sided (duplex) copying using the document glass typically involves manually flipping the original document to scan both sides. Here's a general guide on how to do it:
1. **Place the Document**: Open the document cover and place the first side of your document face-down on the document glass. Align it according to the markers.
2. **Select Copy Settings**: On the control panel, select the "Copy" function and adjust your settings, such as paper size, paper tray, and any other preferences.
3. **Choose 2-Sided Copying**: Navigate to the 2-sided (duplex) copying option on the control panel and select it.
4. **Scan First Side**: Press the "Start" button to scan the first side of the document.
5. **Flip the Document**: After the first side has been scanned, you'll be prompted to flip the document. Remove the original from the glass, flip it over, and place it back on the glass, aligning it as before.
6. **Scan Second Side**: Press the "Start" button again to scan the second side of the document.
7. **Complete the Copy**: After both sides have been scanned, the copier will automatically print out a 2-sided copy of your document.
8. **Retrieve the Copy**: Once the copy is done, retrieve it from the output tray.
9. **Close the Document Cover**: Don't forget to close the document cover when you're finished.
Please note that the exact steps may vary depending on the specific settings and software version of your Sharp MX-3070N. Always refer to your user manual for the most accurate instructions.