Blockchain.info has two different ways of printing a paper wallet

- A paper "backup" which prints the private keys and keeps the keys in the wallet. The funds will still be accessible online so does not improve security, its purpose is so you can still access you coins if something happens to the website or you forget your password.

- A "cold storage" paper wallet which prints a new private key and does not store it in the online wallet. A new address will be added to the wallet labelled (Watch Only) and can only be accessed using the key from the paper.

You want the second way, follow this tutorial https://blockchain.info/wallet/paper-wallet-tutorial-web