We're trying to print white font onto black paper for invitations.
However, the printer is just receiving the paper, but leaving the page blank with no text.
So....
What do we do??

I don't know of any ink jet printer that will print white characters. Normally to print a white font the printer will print everything "but" the font, leaving you with what is essentially white characters. (You'd still have to do it white paper.) That would cost a small fortune in ink if doing more than a few print jobs.

My guess is the best you can do is pick some bright color that the printer can actually print. Say yellow or pink maybe. Even then I'm not too sure how good it would come out on black paper.