-printtoconsole doesn't make it magically start mining. It's literally just an option that causes the debug messages that normally go into the debug.log to also be printed to stdout. It's the same as doing tail -f debug.log while your node is running.

Your node, or some other node in your network, is continuously mining and -printtoconsole has nothing to do with it except that now you are seeing the debug messages.

Are you sure that you are the only node on your network?

What block time did you choose?