When all else fails, try honesty.
I don't mean that you have to tell the professor to his face that you think his field is toxic and that the paper is garbage. But if your honest opinion is that the paper is too trivial to be worth publishing and that you're worried that it might hurt your career, then I would tell the professor that.
If you can suppress your name from the paper more easily, just by declining to work on it, then by all means do that. But it sounds like you've already worked on the paper and can't extricate yourself that easily at this point. In that case I'd recommend just telling the professor that you have had second thoughts and would like to remove your name from the paper, and explain why. The fact that you're a student and he's a professor makes this a scarier prospect, but I don't think your difference in social status should stop you from giving your honest professional opinion on the quality of the work. Intellectual honesty is what we are all striving for in our profession, after all. What's the point in being a scholar if you have to sacrifice honesty?
And maybe you're wrong after all and the paper is more interesting than you think. You won't find this out unless you give the professor an opportunity to openly defend the paper against honest criticism.
Honesty is so rare that it tends to confuse people, who are more accustomed to dealing with lies and excuses than with the straight dope. I know from experience that being honest does risk being misunderstood by people who assume that I can't possibly be telling the truth, so there is some risk of misunderstanding. In the long run, though, I believe that developing a reputation for honesty pays off handsomely, in terms of inner peace if nothing else.