Desktop inkjet printers take both black and color inks for the full spectrum of image production. In any given inkjet cartridge you'll find one or more reservoirs. Thermal remanufactured ink cartridges operate the same way new ones do:
Inside each partitioned reservoir is a heating element with a small metal plate or resistor.
When the printer gives a signal, a current runs through the plate or resistor to warm it up.
The printing fluid surrounding the heated plate is immediately vaporized into a tint air bubble inside the nozzle.
Because there's more liquid at this point than there is room in the nozzle, a droplet is forced out onto the paper.
This process, which takes only milliseconds, is the microcosm of printing around which the larger macrocosm of supply and demand cycle of bulk ink manufacturers takes place.
Stores and printers now offer to refill inkjet cartridges for their customers. However, sometimes the cartridges can't be re-used. When the supply in a cartridge is depleted and printing is attempted anyway, the small metal plate or resistor which is the heating element can burn out and permanently damage the print head. This is why consumers who wish to have the products of bulk ink manufacturers in their used cartridges should not continue to use a cartridge once a low level is indicated. Of course, remanufactured ink cartridges are given new replacement heads in addition to fresh ink supplies. It's an environmentally sound response to the presence of millions of plastic cartridges used worldwide.