Cheap restaurant chains?

I wonder what kind of restaurant chains I will find in Japan, Tokyo specifically, that aren't too expensive?

I'm thinking something less like McDonald's, were you have to get in line for your food, but something that is more like a casual family restaurant, with free water and buttons you press to summon the waiter. Pictures of the food on the menu is a plus, but not necessary.

The most important thing is that it's casual, not too expensive, and if possible the food should be more on the Japanese side rather than European.

The following page contains a list of the family restaurant chains in Japan:
http://de.wikipedia.org/wiki/Familien-Restaurant

And the following contains a list of Izakaya (drinking restaurants) Chains, some of which are also cheap, e.g. Watami:
http://ja.wikipedia.org/wiki/%E5%B1%85%E9%85%92%E5%B1%8B

You can eat at Saizeriya's for less than 1000 yen. It's sort of like Japanese food mixed with Italian cuisine. I highly recommend the doria - it's very cheap (299 yen), delicious and filling.

Yes, saizeria for Italian, but my fave is Gusto/Skylark. They have burgers, but steak, and a good mix of stuff thats Japanese. Denny's is also good. Yoshinoya, Sukiyaki or Matsuya for gyudon/ beef bowls. Oh and Bikkuri Donki :)

Or this, stamina taro. All you can eat for around a thousand yen. http://edo-ichi.jp/stamina/new-menu/