A Question

I keep reading and hearing that the reason we aren't having more inflation now is that banks are keeping the money the Fed pays them for purchasing securities in their reserve accounts and not spending or investing it. So I wonder, where are the banks getting the trillions they are spending to purchase these securities in the first place, and why isn't this spending causing inflation? (I have supposed the commercial banks are just creating the money themselves via fractional reserve banking using the Fed money in their reserves as the required reserves for this money creation.) I think we are really in a severe recession or even a depression, which is being papered over by the Fed's money printing. And this is the real reason for the lower inflation.