Printing BOH reports in Aloha using OKI ML320

[KG602]

I know I'm using an old school workhorse but it works for me except I can't get the font/characters to print clearly on a consistent basis or in larger type. We're using a generic IBM 9 pin driver as the OKI driver(s) print #$@#%$@#^% - literally. I've adjusted the head gap which helped a little but distinguishing 3s, 8s, 6s, & 9s is still difficult. Any help would be appreciated.
Thanks!