If the printer is out of ink in one or more cartridges (the ink light is steady), then with the printer on, lift the scanner unit and use the support to prop it up. Press the Stop button and the (first) empty cartridge will line up with the No Ink symbol on the printer. Press Stop again and the next empty cartridge will be moved to this symbol. Continue to press Stop until the cartridge carrier moves to the ink replacement position (depends on how many cartridges are empty). This is on the right side of the printer. Wait for the cartridge carrier to stop moving. Do not touch the white cable while changing the ink.
Next remove the first ink cartridge by pressing the two tabs towards the center of cartridge and pulling it straight up. (One tab is close to you and the other is closest to the printer.) Take your new cartridge for the slot and shake it four or five times. Then remove the cartridge from the package. Do not touch the green chip. Remove the yellow tape from the bottom of the cartridge. Next rotate the cartridge so that the nozzle is down and facing towards the inside of the printer. Then push it straight down into the slot until it snaps into place. Repeat these steps for the rest of the empty cartridges.
Once all of the empty cartridges have been replaced, lift the scanner unit and push the support to fold it. Close the scanner unit. Press Stop to start charging the ink system. Wait until the Power light stops flashing and remains on before turning off the printer or sending a print job to the unit.
If the Ink light continues to flash, open the scanner unit and press Stop. Press down on the cartridges to make sure that they are completely seated in the cartridge carrier.
If the ink out light is flashing or not lit, you need to use the Epson Utility to change the ink. This is part of the full software from Epson. For Windows right click on the printer icon in the taskbar (bottom right of the screen). Then select Printer Settings and click on the Maintenance tab. For a Mac, open the Applications folder and open Epson Printer Utility 3. Select your printer (if you have several Epson printers listed). Then click OK. (You will need to launch the utility before you open the scanner unit.)
The documentation for the Epson NX110 is available here: http://www.epson.com/cgi-bin/Store/support/supDetail.jsp?BV_SessionID=@@@@1663277658.1305218830@@@@&BV_EngineID=cceeadfdielfldicfngcfkmdhjidfmh.0&cookies=no&infoType=Doc&oid=128284&prodoid=63084353
I hope this helps.