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:
Rather than a moveable print carrier, these E.T.s have a fixed print unit and the same mechanical carriage escapement used in Brother’s electric typewriters.
There’s nothing surprising about the wheel itself, which is a conventional clip-on wheel.
What surprises me 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 …