Quantitative easing didn't work the same way that literally printing money does, something that many who don't have a solid grasp of economics don't understand. QE has kept the money circulating within a very limited span, and was used in part to purchase weak loan assets from banks. While those banks held them, they created significant risk and could impact the minimum holdings required by law. The Fed doesn't have the same kind of problem, and by purchasing the assets (which, collectively, are profitable) it could strengthen the banks and increase its own profit levels. Those profits are then largely sent to the federal government.
QE was also used to purchase a lot of Treasury bonds, but that's much more an accounting maneuver. When the Fed purchases the bonds from the Treasury, it holds them until maturity. When they mature, they're cashed in and the Treasury pays out to the Fed, which becomes part of the Fed's profits, the lion's share of which are turned over to the federal government. However, that part is closer to printing money because it increases the amount of money available to the federal government to spend in the more general economy.
This has turned into an important revenue stream for the federal government. In 2014, the Fed sent $97 billion of its $101 billion in profits to the Treasury. That number may continue to climb for a couple of years, but will decline over time as assets draw down; of the $4.5 trillion in assets held by the Fed, some $800 billion of that is in Treasury bonds that mature by the end of 2016. Other bonds will continue to mature, and loans will be paid off. The money created by the Fed will enter circulation eventually, but it will do so over time, and not in the same way as literally printing the money would have.