Hi, I found these two for you:
http://www.miyazaki-town.com/mypage/mz020239/
3-16-15 Higashi-Omiya
Miyazaki-shi
&
http://www.miyazaki-town.com/mypage/mz020161/
2-2-14 Segashira
Miyazaki-shi
On a side note, I think that japanese coin laundries are far below what I'm used with from Europe (at least all the ones I've tried in Tokyo).