1. Make sure the printer is turned on.
2. Make sure the document cover is closed, then closed, then open the scanner.
(Do not open the scanner when the document cover is open).
3. Press and release the ink button. The 'On' and 'Ink' lights flash.
If one of the cartridges is low or empty the printer moves that cartridge to the 'ink out' mark. Go to step 4.
If no cartridges are low or empty the ink cartridge holder moves to the ink replacement position. Go to step 5.
4. Pree the 'ink' button again.
If more than one cartridge is empty or low the next cartridge moves to the 'ink out' mark.
Once the printer identifies all the empty or low ink cartridges the print head moves to the ink cartridge replacement position.
5. Open the cartridge cover, squeeze the tab at the back of the empty cartridge and lift it out.
6. Before you open the new cartridge package shake it four or five times and remove it from the package .
(Don't remove or tear the label on the cartridge otherwise ink will leak out) .
(Don't touch the green chip on the front of the ink cartridge - you could damage the cartridge).
7. Place the new ink cartridge into the cartridge holder and push it down till it clicks into place.
8. Replace any other cartridges that need replacing.
9. Close the ink cartridge cover and press it until it clicks into place.
10. Close the scanner.
11. Press the 'ink' button. The printer starts charging ink and the 'on' light starts flashing . This takes about a minute . When it's finished the 'on' light stops flashing and remains on and the 'ink' light goes out.
You'll see all the above, with helpful pictures, at this Epson support page