Use Epson L350 (or L300 / L200 Series Scanner) on Ubuntu 16.04/Linux Mint 18 and above

Credit: http://www.linuxquestions.org/questions/linux-hardware-18/scanner-not-detected-4175578422/ (Pedroski and hazel)

To run Epson L350 Scanner on Ubuntu 16.04 / Linux Mint 18 and above, follow the steps below:
  1. Make sure your Epson L350 Printer is fully functional and is printing the documents. Only the Scanner is not working.
  2. Download the Image Scan! for Linux from http://support.epson.net/linux/en/iscan_c.html
  3. Extract the zip file. Open a console, go into that directory and then run sudo ./install.sh
  4. Connect your printer. In the console, enter “lsusb” command. You should see one of the printers listed. In my setup it was
    Bus 002 Device 006: ID 04b8:08a1 Seiko Epson Corp.
  5. Because you installed iscan, you will now find a new file /etc/sane.d/epkowa.conf available. Edit that file through
    sudo gedit /etc/sane.d/epkowa.conf (You can use xed or vi)
  6. After the line “#usb 0x04b8 0x0110“, enter the line “usb 04b8 08a1“. Save it. (change it based on the device ID you see in lsusb. Note that the colon “:” is no longer there).
  7. In the other /etc/sane.d/epson* files, comment out all lines with a # (or remove those files altogether).
  8. Disconnect the printer, and reconnect. On the console, run sudo scanimage -L and see if the scanner is visible.
  9. Open Simple Scan, and it should scan properly.
Reason why the Scanner is not working is because in Ubuntu 16.04
“SANE requires either a usb vendor/model code or a scanner device created by a kernel module but not both. They interfere with each other. And the kernel scanner module is deprecated now. You’re supposed to use libusb.”.