Q: It does print out colour. What can be wrong?
A: Is there anything wrong with the "color" that is printed? Maybe a shade or 2 off? Maybe your black cartridge is empty or clogged. Check your settings. If the cartridge is 1/4 full, maybe something (or someone) caused a change in the settings. You may want to replace the cartridge anyway since it may be empty or close to it. Afterall the pc only gives you an estimate of the ink in the cartridge.