Inkjet printhead with drive circuitry controlling variable firing sequences
View Patent ↗An inkjet printhead includes: an array of ink ejection nozzles, an actuator for each nozzle and drive circuitry for receiving print data from a printhead controller and distributing fire signals to the actuators. The drive circuitry is configured to fire the actuators such that a first firing sequence for a first line of print is different to a second firing sequence for a subsequent second line of print.
1. An inkjet printhead comprising:
an array of ink ejection nozzles;
a plurality of actuators, each actuator being associated with a respective one of the nozzles for ejection of ink from said nozzle; and
drive circuitry for receiving print data from a printhead controller and distributing fire signals to the actuators;
wherein the drive circuitry is configured to fire the actuators such that a first firing sequence for a first line of print is different to a second firing sequence for a subsequent second line of print, and
wherein the drive circuitry has nozzle enable latches for each of the actuators respectively, each nozzle enable latch holding a fire signal for the nozzles selected to fire in the next line of print, and shift registers for loading the fire signals to the latches in accordance with the print data received from the printhead controller, the shift registers being configured to load the latches of the selected nozzles for one line of print while the nozzles selected for the previous line of print are firing.
2. A printhead according to claim 1 wherein the array of nozzles is supplied with different colored inks and the drive circuitry determines that nozzles of the same color selected to fire in one line of print, are maximally spaced from each other.
3. A printhead according to claim 2 wherein the nozzles of the same color selected to fire in one line of print are fired simultaneously.
4. A printhead according to claim 1 wherein the nozzles, the actuators and the drive circuitry are all fabricated on a single monolithic wafer substrate.
5. A printhead according to claim 1 wherein the printhead is a pagewidth printhead.
6. A printhead according to claim 2 wherein the drive circuitry ensures that a minimum spacing of five nozzles between simultaneously firing nozzles of the same color.
7. A printhead according to claim 2 wherein the drive circuitry divides the nozzles of the same color into groups of less than twenty, and only allows a maximum of one nozzle in each of the groups to fire when printing a single print line.
8. A printhead according to claim 7 wherein the drive circuitry indexes through all the nozzles in each group before firing any nozzle in one group twice.