Signaling method for printhead
View Patent ↗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.
1. A signaling method for a printhead, the method comprising the steps of:
providing a printhead comprising a plurality of nozzles, each nozzle having an associated actuator for ejecting ink and associated drive circuitry for operating the actuator;
providing a print engine controller for generating drive signals in accordance with print data defining a print job for the printhead; and
selectively providing each of the actuators 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.
2. A signaling method according to claim 1 wherein the printhead has a temperature sensor for sensing the temperature of the ink at one or more of the nozzles, and one of the signals in the combination of signals is output from the temperature sensor.
3. A signaling method according to claim 2 wherein the printhead has one of the temperature sensors for each of the nozzles respectively.
4. A signaling method according to claim 1 wherein the print engine controller monitors the time period since one or more of the nozzles last ejected ink.
5. A signaling method according to claim 4 wherein one of the signals in the combination of signals relates to the time period since one or more of the nozzles last ejected ink.
6. A signaling method according to claim 1 wherein the printhead has thermal bend actuators for each of the nozzles respectively, each of the thermal bend actuators configured to impart kinetic energy to the ink such that it ejects from the corresponding nozzle.
7. A signaling method according to claim 6 wherein the drive signal has a series of clock pulses, each clock pulse having sufficient energy for one of the actuators to eject ink from the corresponding nozzle.
8. A signaling method according to claim 7 wherein the pre-heat signal has a series of heat pulses, each heat pulse having insufficient energy for one of the actuators to eject ink from a corresponding nozzle.