I sent a photo of the cartridge with the kanji label to my son who lives in Tokyo and is a scholar in Japanese. Here is his response: "I think it says “Tsuji” which is just a family name. I can tell you it
has no functional meaning in terms of what the cartridge can do. It’s
also so roughly written (like a signature) that I’m not 100% sure that
it it is the character for “Tsuji”'.
I hope that helps someone.
I hope that helps someone.