Printhead IC with more than 10000 nozzles in the exposure area of a photo-imaging device
View Patent ↗A printhead integrated circuit for an inkjet printer that has a monolithic wafer substrate supporting an array of droplet ejectors for ejecting drops of printing fluid onto print media. Each droplet ejector has nozzle and an actuator for ejecting a drop of printing fluid the nozzle. The array is formed on the monolithic wafer substrate by a succession of photolithographic etching and deposition steps involving a photo-imaging device that exposes an exposure area to light focused to project a pattern onto the monolithic substrate. The array has more than 10000 of the droplet ejectors configured to be encompassed by the exposure area. The invention arranges the nozzle array such that the droplet ejector density is very high and the number of exposure steps required is reduced.
1. A printhead integrated circuit for an inkjet printer, the printhead integrated circuit comprising:
a monolithic wafer substrate supporting an array of droplet ejectors for ejecting drops of printing fluid onto print media, each droplet ejector having a nozzle and an actuator for ejecting a drop of printing fluid through the nozzle, the array being formed on the monolithic wafer substrate by a succession of photolithographic etching and deposition steps involving a photo-imaging device that exposes an exposure area to light focused to project a pattern onto the monolithic substrate; wherein,
the array has more than 10000 of the droplet ejectors configured to be encompassed by the exposure area and the array has more than 700 of the droplet ejectors per square millimeter.
2. A printhead integrated circuit according to claim 1 wherein the exposure area is less than 900 mm 2 .
3. A printhead integrated circuit according to claim 1 wherein the monolithic wafer substrate is encompassed by the exposure area.
4. A printhead integrated circuit according to claim 1 wherein the photo-imaging device is a stepper that exposes an entire reticle simultaneously.
5. A printhead integrated circuit according to claim 1 wherein the photo-imaging device is a scanner that scans a narrow band of light across the exposure area to expose a reticle.
6. A printhead integrated circuit according to claim 1 wherein the monolithic wafer substrate supports more than 12000 of the droplet ejectors.
7. A printhead integrated circuit according to claim 1 assembled onto a pagewidth printhead with other like printhead ICs, for ejecting drops of printing fluid onto print media fed passed the printhead in a media feed direction, wherein,
the printhead has more than 100000 of the droplet ejectors and extends in a direction transverse to the media feed direct between 200 mm and 330 mm.
8. A printhead integrated circuit according to claim 7 wherein the nozzles are spaced apart from each other by less than 10 microns in the direction perpendicular to the media feed direction.
9. A printhead integrated circuit according to claim 7 wherein the printhead has more than 140000 of the droplet ejectors.
10. A printhead integrated circuit according to claim 7 wherein the nozzles that are spaced apart from each other by less than 10 microns in the direction perpendicular to the media feed direction, are also spaced apart from each other in the media feed direction by less than 150 microns.
11. A printhead integrated circuit according to claim 1 wherein the actuators are arranged in adjacent rows, each having electrodes spaced from each other in a direction transverse to the rows for connection to respective drive transistors and a power supply; wherein,
the electrodes of the actuators in adjacent rows have opposing polarities such that the actuators in adjacent rows have opposing current flow directions.
12. A printhead integrated circuit according to claim 11 wherein the electrodes in each row are offset from its adjacent actuators in a direction transverse to the row such that the electrodes of every second actuator are collinear.
13. A printhead integrated circuit according to claim 11 wherein the droplet ejectors are fabricated on an elongate wafer substrate extending parallel to the rows of the actuators, and power and data supplied along a long edge of the wafer substrate.
14. A printhead integrated circuit according to claim 7 wherein the printhead has a print engine controller (PEC) for sending print data to the array of nozzles; wherein,
during use the print engine controller can selectively reduce the print resolution by apportioning print data for a single nozzle between at least two nozzles of the array.
15. A printhead integrated circuit according to claim 14 wherein the two nozzles are positioned in the array such that they are nearest neighbours in a direction transverse to the movement of the printhead relative to a print media substrate.
16. A printhead integrated circuit according to claim 15 wherein the PEC shares the print data equally between the two nozzles in the array.
17. A printhead integrated circuit according to claim 15 wherein the two nozzles are spaced at less than 40 micron centers.
18. A printhead integrated circuit according to claim 15 wherein the printhead has a nozzle pitch greater than 1600 nozzle per inch (npi) in a direction transverse to a media feed direction.
19. A printhead integrated circuit according to claim 15 wherein the nozzle pitch is greater than 3000 npi.