Here’s a rare find: This Brother M8300/9300 compatible print wheel came up on German eBay …
These print wheels were used in Brother’s (JP-16) M-series 8300/Correctronic and 9300/Executron portable electronic typewriters:
There’s nothing surprising about the wheel itself. It’s a conventional clip-on wheel:
The M8300/9300, however, is an unconventional daisy wheel typewriter with a fixed print unit; one that can be tilted back (once the ribbon cartridge is removed) for wheel removal and insertion.
The Electronic 9300 has the same mechanical carriage escapement used in electric typewriters, which means when you buy one of these typewriters you choose between a 10 pitch or a 12 pitch machine. The wheel that comes with it will either be a 10 pitch or a 12 pitch wheel, depending on the machine you have, plus a 10/12 pitch (typically Script as pictured) wheel that can be used in either machine.
What surprises me MORE is the fact that Brother’s FIRST office electronic typewriter takes the same drop-in cassette wheel used in all future Brother E.T.s (the M8300/9300 excepted).
Given these early E.T.s (the EM-1 was first released in 1980) take a Selectric ribbon, I would have expected them to also take a rudimentary clip-on wheel.
However, this online image, taken at the Brother Museum in Nagoya, Japan, tells me otherwise …
A tabbed cassette wheel is prominently positioned against the platen of an EM-1.
“Interchangeable cassette print wheels” are also mentioned in advertising of the time …