A chip used for dispensing a fluid such as ink provides ink-dispensing ejectors having an ink cavity over a supporting substrate, and further provides a heater for heating the ink in the cavity. The heater can be interposed between the substrate and the ink cavity to provide direct heating of ink as it is being dispensed. Various embodiments further comprise the use of the heater structure as a temperature probe to measure the temperature of the ink in the ink cavity. Other embodiments provide a chip having both a temperature probe and a heater as separate structures interposed between the ink cavity and the substrate. Further described is a temperature probe and/or heater which traverses a majority of a width of a substrate, and surrounds each drop ejector on at least two sides.