PRINTHEAD IC WITH SUB EJECTION CONTROL
A printhead IC is provided having an array of ejection nozzles, sensing circuitry for sensing a temperature of the nozzle array which is de-activatable after a period of use, and drive circuitry for receiving print data and providing drive pulses to the nozzles to cause ejection in accordance with the print data. The drive circuitry is configured to set the duration of the drive pulses to a sub-ejection value for any nozzle which is not to eject in accordance with the print data.
1 . A printhead IC comprising:
an array of ejection nozzles;
sensing circuitry for sensing a temperature of the nozzle array, the sensing circuitry being de-activatable after a period of use; and
drive circuitry for receiving print data and providing drive pulses to the nozzles to cause ejection in accordance with the print data, the drive circuitry being configured to set the duration of the drive pulses to a sub-ejection value for any nozzle which is not to eject in accordance with the print data.
2 . A printhead IC according to claim 1 wherein the array is arranged into rows and columns of the nozzles, the drive circuitry being configured to provide drive pulses to the nozzles row by row.
3 . A printhead IC according to claim 1 wherein the drive circuitry provides the drive pulses to the nozzles to cause ejection in a predetermined sequence.
4 . A printhead IC according to claim 1 wherein the drive circuitry extracts a clock signal from the print data.
5 . A printhead IC according to claim 1 wherein the drive circuitry resets itself to a known state in response to receiving power from a power source after a period of not receiving power from the power source.
6 . A printhead IC according to claim 1 wherein the drive circuitry is configured to receive the print data in any one of a plurality of different data transmission protocols.