My uninformed guess is an RFID tag in each refill bag. The printer will scan for Genuine Authorized Original Virtuous Toner, and only then allow the fill port to open. Once open you have one hour before that tag ID is burned and can't be used further.

Or maybe you need to use the app and do this? (https://ssl-product-images.www8-hp.com/pub/msc/C26A0B64-54DB...)

Whatever the mechanism, reviews are not good: https://www.hp.com/us-en/shop/pdp/hp-143a-black-original-nev...

If this is how it works, then I don't think they'd burn a tag. People will inevitably do a partial fill or maybe even just open it up to see how it works. And if there are multiple tags, which one does it burn?

The bottles also do not appear to be one time use.

I love how they market that as protecting the end user from counterfeit.

Seems like an interesting reverse engineering project.

I can't speak for this printer, but I have an HP Neverstop 1001NW which uses a similar tank-based system. The container of toner that came with it appeared to be entirely dumb.

uhh.. or maybe just chemistry? you can fill the tank with urine if you want but YMMV.

That's fine for the magenta but what about the cyan, yellow, and black?

You might be eating too many beets ;)

Methylene blue works both as a nootropic and a cyan urine ink source! (Dosing is often roughly "keep going until you pee blue all the time"...)