There have been a few good threads on this
You are their homeroom teacher
You have a Japanese teacher license?
I find it best to be honest with yourself and with the kids. I tend to take a no nonsense approach with them and also let them know i'll respect them if they'll respect me. We can both make each other's lives a little better.
Of course those daily notebooks are a waste of everyone's time, but can you leverage those notebooks in some way to get them to hand them in some of the time? Maybe allow them to paste in their cram school work to get credit. After all, they did study.
Then increase the value of those notebooks toward their scores and thus penalize them if they don't do it. But more than that reward them more for that daily effort.
All in all, it's about getting them to do what they need to do for their own benefit. Since there isn't any discipline structure in Japan and you are responsibile for their future, not them, I think it requires some creative thinking.
The other option is just, again be honest, and let them know you will allow them to hang themselves. It's often very frightening for Japanese children to hear that someone isn't going to look after them. Write all of their behavior issues in their records and let the truth speak for itself. That might get you in some trouble with your administration but also might be a good chance to have them actually step in and give you some other alternatives (other than take it on the chin
and just awit them out till graduation - then you're all doing time)