It is hard to give a variegated Rubber Plant too much indoor light, so I don't think that is the cause of the leaf edge burning. Possible causes are improper watering, using hard water, over fertilizing and the leaves coming in contact with hot surfaces.
When you water, add enough so that a small amount trickles through the drain holes. Then water again as soon as the top half-inch of soil feels dry. If your tap water is hard, use filtered or distilled. If you have been fertilizing, stop.
It is possible the damage you are seeing now was caused by improper care prior to your getting it. It can take a while for symptoms to appears. So don't over-react.
If new leaves that come in are healthy, you know you are on the right track. The damaged leaves can be removed entirely or just trimmed to remove the brown edges. Pruning and trimming will have no effect on the overall health of the plant.
