I remember when I was younger watching a cartoon movie but I can't remember whether it was from the 80's or early 90's. I remember it started with people working in a mine and some guy uncovered a handle to some kind of sword. I think the guy who found it was a slave. I think the handle developed an invisible blade to stab bad guys but it wouldn't work on good pope. When he got free from the mine I vaguely remember a ship looking a little like the one Hans Solo (a star wars ship) in the movie. I think there were robots in this film and mutants (or just deformed villains) in the movie.

Other little things I remember:

One bad guy seemed to be half person half robot

I think the main good guy went in a prison or cell more pat of the movie.

Starchaser: The Legend of Orin (1985) (http://www.imdb.com/title/tt0090065/)

Omfg I was JUST thinking about this today (I suffered a blunt trauma to the head, resulting in partial amnesia and I get REALLY excited about remembering stuff from my childhood!) and it's bugging the hell out of me! Did you ever find out?