Quantitative easing (sometimes mistaking called "money printing") isn't directly inflationary. Because when central banks buy bonds, they do not pay with normal money. Instead, they pay with a special type of money that can never enter the real economy (as to not create inflation). This special type of money are called "bank reserves". And bank reserves can only be used to 1) settle interbank transfers and 2) buy more bonds. They can never leave the loop of the banking system. So the next time you see scary looking charts showing that the total amount of money increased a lot in the last two years, keep in mind that that "money" includes bank reserves that are stuck in a closed loop. This is also why Japan, who is the king of QE and "money printing", barely has any inflation.
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