Some black cartridges contain a metal bellow that gradually expands when ink is injected and gradually contracts as the ink is consumed during printing. Pressure on the other side of the bellows regulates the dispensation of the ink. HP cartridges are remanufactured industrially and the process is identical to that employed by the refill kit. This has to do with heat. The drier the cartridge the hotter the metal electrodes which are part of the printhead.
Excessive heat tends to damage the electrodes.
Faulty electrode pairs break the chain. They are extensively used in office, libraries etc. For these we have designed the Jet-Express. You snap in the cartridge into the Jet Express and pressure feed the ink via the printhead into the reservoir. Lower the lever once and the job is completed.