Search the Designer Help for "Visible but don't print" and you'll find the "Setting object visibility" topic. It says the following:
If you want to make another object visible or invisible only for printing, you can do this through script written to the object's prePrint and postPrint events and set to run at the client. For example, if you have a visible object that you do not want to appear when the form is printed, you could add this JavaScript to the object's prePrint event:
this.presence = "invisible";
To make the object visible again after the form is printed, add this JavaScript to the object's postPrint event:
this.presence = "visible";
Note: If you use script to change the presence setting of an object for a PDF form, you should save the form as a dynamic PDF.
Regards,
Rob
Four Point Solutions