Does anyone know how the printhead elements are able to heat and cool rapidly enough? Is it just a very thin amount of a particular alloy and a precise amount a

Does anyone know how the printhead elements are able to heat and cool rapidly enough? Is it just a very thin amount of a particular alloy and a precise amount and duration of voltage? Especially the cooling off part seems like it would require a really specific material. Unless all of the heat is someone removed as the paper scrolls.