Luggage storage at tokyo station

I will be traveling from toyama to tokyo station by shinkansen, estimate reach before noon, walk around tokyo station and then head to narita JR station in the evening.
1) any locker/luggage storage at tokyo station maybe for the half day?
2)any place to place luggage(20inch) in JR train from tokyo to narita?

1. There are lots of them spreading across the station.

2. NEX has lots of spaces for large luggage.

Yes, there are coin lockers. Eg: http://www.tokyostationcity.com/en/information/locker.html

If you take NEX to Narita it has a dedicated luggage area in each car at the entrance for larger suitcases.

Enjoy your afternoon in Tokyo!

There is a luggage room also at Tokyo station if you cannot find a suitable size locker.