According to http://www.samsbusinessmachines.com/help2.htm your copier may have worn "Fuser Rollers". These are heating rollers which fuse the toner to the paper and if worn will produce poor quality copies and cause paper jams too.
Your copier may also have dirty "Corona Charge Wire Assemblies". Theory of these can be found at: home.maine.rr.com/randylinscott/copier.htm
These are units that produce an electrical reaction with the drum in your copier and if dirty will affect copy quality. Make sure you don't touch the drum as it can be easily damaged beyond repair. Clean the Corona units with a can of compressed air, then use a Q-tip moistened with Isopropanol to gently clean the Corona unit wires.
Suggestions to be used at own risk and are courtesy Samsbusinessmachines.com.
Ian
November 2006