but you need some kind of OCR (Optical Character Recognition) software to get from the scan to word format. There are a few that does a decent job of English but I assume Japanese is harder. There is usually also a fair bit of proofreading involved.
http://www.makeuseof.com/tag/top-5-free-ocr-software-tools-to-convert-your-images-into-text-nb/
- martin
