I have a Fujitsu S1300, and a MacBook Pro 15″ with Yosemite.
My patience is running thin. I can scan using Fujitsu's software. But I can't using Preview.
But when I look at Preview > File > Import from Scanner, it's greyed out.
I've done all the things listed here.
And... there is paper in the loader. I'm connected directly to usb (no hub).
PS: I was inspired to use preview to scan from this article.