Calling stations with the best hand

I play smaller stakes aggressively and am a winning player. One thing that hurts my profit is when some one has me beat and only calls my raises. For example if I have A-J (which I obviously led out with) and am against A-k with an A on the board I will raise. If the board is not coordinated so I have no reason to suspect a sandbag, I generally keep pushing.

Here and there, I am beat by the passive caller after pumping in 2.5 more big bets. Am I playing right? I think so, but I am wondering if there is anything else I can do to get a passive player to tell me more about his or her hand?