The article linked in the OP was not really too specific on the technology. It said "Using 3-D printing and human cells", which is not quite as clear on the overall process of creating tiny livers. The second link I provided was much more clear in that the human cells was the material used for printing:
"Like other forms of 3D printing, bio-printing lays down layer after layer of material -- in this case, live cells -- to form a solid physical entity -- in this case, human tissue."
Really, that's what they whole mix up for me was at first. From what little I know of 3D printing, most to this point use polymers as the printing material. I was then going with this, because the original article was not all that clear, and then trying to envision where in the process the human cells came into play. Again, the two links I provided cleared it up for me.