You may wish to remove the ink cartridges if you are planning a radical disassembly, though this is not necessary for the purposes of this guide. Follow the instructions in the User Manual, and place them in a polythene bag, both to prevent them drying out and to avoid ink stains on your work surface or clothes.
Switch off the printer if it's on, by pressing the power button and waiting for the power light to stop flashing. Now unplug the power cable and USB lead (if connected).
Lift the scanner lid as far as it will go. Squeeze the finger in the centre of each hinge in order to detach it.