A signaling method for a printhead with nozzles for ejecting ink, and associated drive circuitry for operating the nozzles that receives drive signals from a print engine controller. The print engine controller generates the drive signals in accordance with print data defining a print job for the printhead. A pre-heating determination unit selectively provides the printhead with a pre-heat signal derived from a combination of signals, at least one of the signals in the combination being the drive signals from the print engine controller. Processing within the controller is more efficient if determining whether pre-heating is necessary is restricted only to those nozzles which are to receive print data.