An alternative to consider are dot matrix / impact printers.

They are used in kitchens, as heat sensitive paper doesn't work well there. It's just plain paper and an ink ribbon.

Same underlying protocol as thermal printers, so the code is mostly plug and play.

They often can print in two colours (red and black). And sound like the 1980s.

I... thought dot matrix printers were some of the worst for releasing particulate matter into the air? Especially ultra fine particles?

I can't find any information regarding this.

Thanks, you're right, a quick google shows nothing... I could've sworn reading about how they're very bad... perhaps I was misremembering with standard printers?

You can buy phenol free paper

https://www.pca.state.mn.us/business-with-us/bpa-and-bps-in-...

There's also this which works using a purely physical process: https://www.koehlerpaper.com/en/products/Thermal-paper/TH_Bl...

Check out some results here: https://thermalprintcameras.wordpress.com/blue4est-paper/

I use Niimbot M2_H which uses thermal transfer technology, and it’s more durable and lasts longer than thermal ones, BPA free as well.