The green light is blinking constantly and the printer won't print

When the green lamp constantly blinking this mean one or both print head are defective.Here we can find which cartridge is defective.Open cover put out color cartridge then close cover.If blinking stops replace color cartridge.If blinking continues put out black cartridge and put in color.If blinking stops replace black cartridge, if not stop replace both cartridges.
This printer can work with only one cartridge.If you don't use color printing just remove the color cartridge.