In order for printers ink to set it needs a carrier. Liquin is a fine carrier, as are other oil painting media. The liquid that separates from enamel metallic paint works well too.
I use Grumbacher Oil Painting Medium #1 as a carrier for printer's inks myself. All listed above work as well. It is very important to use these and experimentation will prove which works best for you. The point is to get the inks on in an even application and dry as smooth as possible. You will know when you get the right mix.
Jim