My scan is too light to read, The source is inkjet printed.

What print quality setting are you using? Some printers are so conservative on draft mode, it's useless beyond a proof - probably by design. I would rerun it in normal, and see what happens. I use Epson scanners generally speaking, and they do fine with draft scans, but I can properly tweak the final image to work around any lightness issues - I think the NeatDesk is fully automatic, so you need to adjust the image you are scanning.

The other thing I would check is the scanning element - it might be dirty. Get a microfiber, clean it and see if the issue remains.