I find that you have to make sure the window is narrow enough to fit into the page size.
Hi Steve,
What did you do to get that 2nd printout? (I presume that is exactly the same problem that larryknight49 has described)
When you say “window”, I presume you mean the Score Editor on screen? Here, on screen, I actually got 4 bars of 16th-notes, which, in Print Preview, changed to 3 bars (with Page Setup set to A4 of course 
)