removed by the ejected drop itself and the ink that is taken into the printhead from the ink reservoir not shown the result of this is that the net u201c movement u201d of heat will be outwards from the printhead to provide for automatic cooling under these circumstances the printhead does not require any other cooling systems as the ink drop 16 ejected and the amount of ink 11 drawn into the printhead to replace the ejected drop are constituted by the same type of liquid and will essentially be of the same mass it is convenient to express the net movement of energy as on the one hand the energy added by the heating of the element 10 and on the other hand the net removal of heat energy that results from ejecting the ink drop 16 and the intake of the replacement quantity of ink 11 assuming that the replacement quantity of ink 11 is at ambient temperature the change in energy due to net movement of the ejected and replacement quantities of ink can conveniently be expressed as the heat that would be required to raise the temperature of the ejected drop 16 if it were at ambient temperature to the actual temperature of the drop as it is ejected it will be appreciated that a determination of whether the above criteria are met depends on what constitutes the ambient temperature in the present case the temperature that is taken to be the ambient temperature is the temperature at which ink 11 enters the printhead from the ink storage reservoir not shown which is connected in fluid flow communication to the inlet passages 9 of the printhead typically the ambient temperature will be the room ambient temperature which is.