Save part of a part, to STL for printing

I have a huge part part that has a lot of bodies .  My problem I want to print one of the bodies.  When I turn off visibility of all unwanted features and have only the part I want to print visible and save it to STL,  then when I import it into my printer graphics area ,  all the model shows up.  How do I save so I can only print this small portion of my file?

Thanks

JB

SolidworksParts And Features