When I irimi in and atemi uke should be forced back my problem is I can,t keep him going back.any help is appreciated
I'd be thinking more in terms of disrupt - redirect than force back..
Disrupt the initial attack by entering before it gets too strong, then redirect uke's original forward intention off the line of attack.
Force back sounds more like a clash of energies to me, thereby causing uke to resist. Uke will resist subconsciously if you try to force him - it's an automatic reaction which I teach our students to be aware of