Three comments here:
1. I don't think this is a Word issue but printer.
2. Does the printer do duplex (double-sided) printing? Check the printer
manual for instruction on how to set up the printer to do this, or how to do
it manually.
3. Are you saying that the landscape page is not printing in landscape but
cut off along the right side of the page?
Check the printer driver settings for something along the lines of
'autorotate'. Check your printer manual or contact the manufacturer.
Best of luck
DeanH