Abstract: The temperature of the ejector (12) of a thermal ink jet print head (10) is maintained within acceptable operating limits by measuring the current temperature, predicting the heat loading on a subsequent pass over a printing medium (32), and adjusting the temperature of the ejector (12), as necessary, by heating the ejector (12) or modifying the operation of the printer (60) to permit cooling of the ejector (12). The temperature of the ejector (12) is preferably measured by a thin film temperature measurement resistor (94) codeposited onto a substrate (14) with the thin film ejection resistors (22) that generate the droplets ejected from the ejector (12). Heating of the ejector (12) is preferably accomplished by passing a low level current through the ejection resistors (22). Cooling is preferably accomplished without the use of a fan by delaying the printing pass, or reducing the heat load during the printing pass by slowing the printing rate during that pass only.