DIAGNOSIS That grinding is the scanner carriage motor straining because something is blocking its path. The most common culprit is a small object—a paperclip, staple, or bit of crumpled paper—that fell onto the glass and got under the scanning assembly.
FIX 1) Unplug the printer from the wall. 2) Lift the scanner lid and look closely at the white scanner strip (the bar that spans the width under the glass) and the rails it moves on. 3) Using a flashlight, check for any foreign debris. If you see something, use a pair of tweezers or a cotton swab to carefully remove it. 4) Gently try to move the scanner assembly by hand from one side to the other; it should move smoothly. 5) Plug the printer back in and try a copy.
IF THAT DIDN'T WORK If the carriage moves freely but still grinds when powered on, the scanner assembly might have jumped its track. This is a more involved fix that usually requires opening the scanner unit's housing to reseat the belt and carriage—if you're not comfortable with that, it's time to contact HP support.
HEADS UP Always close the scanner lid when not in use. An open lid is an invitation for dust and small items to fall onto the glass and cause this exact issue.