That's
because it was... there is a different command to display the
output rather than print it...
I believe that command was 'disp'.
The disp command on the HP71 and HP75 was just like print only it used
the display rather than the printer.
And there are statements something like "printer is" and "display is"
that
allow you to reassign the I/O devices. Unfortunately I don't remember
the details, and I don't have my -71 manuals handy.