Used to be that printing a text file was just `cat myfile.txt > /dev/lp0` .
It has been a while since I printed a plain text file, but I guess there's still a similar command available with some research.
Since then printers progressively forgot how to cope with such "documents", though IIRC good-old HP "PCL" should only require about a bare minimum of framing/job control to get a modern printer to handle ASCII plain text.