Yoshiro Nakamatsu
Among Nakamatsu's early inventions is the Shoyu Churu Churu, a siphon pump used in the home to move soy sauce from large containers to smaller vessels for cooking and serving. His patented inventions include:
Based upon a patent issued in 1952, Nakamatsu claims to have invented the first floppy disk well before IBM's floppy disk patent was filed in 1969. However, what Nakamatsu patented in 1952 was a paper for optical sound player. In contrast to a floppy disk, this Nakamatsu patent discloses the use of printed paper for storage instead of the magnetic material of a floppy disk. It is not rewritable and lacks most elements of the IBM floppy disk patent. Since the paper was 'floppy' material, he claims he had invented the floppy disk (sometimes he uses the phrase "floppy media"); however, it should be noted that flexible magnetic recording media was well known prior to 1952, in tape and wire recording.
History of the floppy disk
Like the -inch, the -inch disk underwent an evolution of its own. When Apple introduced the Macintosh in 1984, it used single-sided -inch disk drives with an advertised capacity of 400 kB. The encoding technique used by these drives was known as GCR, or Group Coded Recording (similar recording methods were used by Commodore on its -inch drives and Sirius Systems Technology in its Victor 9000 non-PC-compatible MS-DOS machine). 
Somewhat later, PC-compatible machines began using single-sided -inch disks with an advertised capacity of 360 kB (the same as a double-sided -inch disk), and a different, incompatible recording format called MFM (Modified Frequency Modulation). GCR and MFM drives (and their formatted disks) were incompatible, although the physical disks were the same. In 1986, Apple introduced double-sided, 800 kB disks, still using GCR, and soon after, IBM began using 720 kB double-sided double-density MFM disks in PCs like the IBM PC Convertible. IBM PC compatibles adopted it too, while the Amiga used MFM encoding on the same disks to give a capacity of 1 MB (880 KB available once formatted).