Maybe one of your cartridges. I am not sure if your model can print with only one cartridge, but you can try removing one of them and see if the light is still blinking. If it is, try putting the other cartridge in. If it still won't work, try printing something from your pc. You will probably get a warning sign that will explain what is wrong. If it says: problem with black ink cartridge, or problem with right cartridge, then you should replace it.
If that doesn't work, please let me know, i wish to help solve your problem.