The hack is quite literally as simple as injecting a refillable printer ... including instant prototyping using nothing but scotch tape. If anyone can source some of this ink and try it out ...
Demand for the Instant Ink service has grown substantially during the pandemic amid the rise in needing to print at home. Subscriber count has doubled from the 5 million Instant Ink subscribers ...
Ofek, Elie, and Marco Bertini. "HP Instant Ink: (Self) Disrupting the Consumer Printing Market." Harvard Business School Teaching Note 521-084, February 2021.