MODS: please move to CSS section
you can designate a separate stylesheet for printing when you link you css file (assuming you are linking an external css)
assuming you have a 'main' css file called main.css, and that you link it, you should have this in your html file:
copy your main css file, which i'm assuming gives a height to the table, to a new file, let's call it print.css. in the print.css file, take off the table height. now add this extra link line below the other css link:
when you "print preview" you should now see all rows for your table