Canon Typestar 10-II electronic typewriter main board. CPU is a Renesas 3806-family, directly controlling keyboard matrix, LCD display, paper feeding and indirectly controlling printing head. i wanted to make it into a serial printer by emulating the keyboard matrix but no luck

turns out emulating a matrix keyboard is a bit more involved than just pulling a wire high or low, and would require quite a few ancillary ICs than just a microcontroller. unfortunately i see no other point of attack to automate keypresses on this rn, defeating my plan for now

the typewriter itself is neat but clearly a very cost-cut model about a decade into the typestar line. earlier models had options such as serial and typeface cartridges, which this lacks. it can print on regular paper, provided you have the rare thermal tape, or any thermal paper

incidentally, these types of thermal ink tape typewriters are infamous for being notorious security liabilities. the way they print on regular paper is thru melting off ink similar to toner onto paper, leaving a very clear negative of whatever you wrote onto the disposable tape

however, this presents an interesting hack: those ink tape cartridges are not supposed to be reusable, but since so much ink is left on them, if you're careful enough you can take it apart and re-spool the tape anew. the print will be far from perfect, but it works

by the way before someone corrects me yeah i know it's not exactly ink that's on those tapes, it's more like a layer of toner adhered to a plastic film tape, which then melts with the printing head, forming letters on the paper. i'm just using "ink" to work around character limit