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Under Hardware > USB, you should see your Epson scanner device in the USB Device Tree, you can unplug and replug the USB connection to make sure it is the scanner device (as it should disappear and reappear). This is one way to make sure you are making a physical connection. If not check it with another a known working USB cable.
If you do not see your peripheral connected, it could mean that the device is not working or is not supported on your computer.