To be more precise, you are using the moniker "money printing" to confuse the issue. See, inflation isn't caused by printing money, inflation is caused by spending. If there is too much spending power going around and the productive capacity of the economy cannot keep up, then prices are going to be bid up.

QE isn't going to cause much more spending, because as grandparent correctly stated, nobody's total amount of assets is going to be changed by QE. After all, suppose you hold long term treasury bonds. Now the Fed offers to buy them at a higher price. Maybe you will take that offer. And maybe you'll use that money to buy some other class of assets. But will you now actually put that money into the real economy, buying some produced goods or services that you would not otherwise have bought?

Most people won't do the latter, and that's why QE isn't going to cause additional spending, and this is why it isn't going to cause inflation.

Note that this is very different from historical episodes where money was printed by the government for direct spending, e.g. by the southern US states during the civil war.