Printhead system for modulating printhead peak power requirement using redundant nozzles
View Patent ↗A printhead system comprising an inkjet printhead and a printer controller for supplying dot data to the printhead is provided. The printhead comprises a plurality of first nozzles and a plurality of second nozzles supplied with a same colored ink. The first nozzles and second nozzles are configured in a plurality of sets, wherein each set of nozzles comprises one first nozzle and one corresponding second nozzle. Each nozzle in a set is configurable by the printer controller to print a dot of the ink onto a substantially same position on a print medium. The printer controller is programmed to supply dot data such that the first nozzles and the second nozzles each contribute dots to a line of printing.
1. A printhead system comprising a stationary pagewidth inkjet printhead and a printer controller for supplying dot data to said printhead,
said printhead comprising a plurality of first nozzles and a plurality of second nozzles supplied with a same colored ink, said first nozzles and second nozzles being configured in a plurality of sets, wherein each set of nozzles comprises one first nozzle from the plurality of first nozzles and one corresponding second nozzle from the plurality of second nozzles, all nozzles in a set being configurable by said printer controller to print a dot of said ink into a same position on a print medium fed transversely past said printhead,
said printer controller being programmed to supply dot data such that said first nozzles and said second nozzles each contribute dots to a line of printing, wherein said printhead comprises a plurality of transversely aligned color channels, each color channel comprising at least one nozzle row extending longitudinally along said printhead, each nozzle in a color channel ejecting the same colored ink,
wherein said first nozzles are contained in a first color channel and said second nozzles are contained in a second color channel,
wherein said printhead is comprised of a plurality of printhead modules, each printhead module comprising a respective segment of each nozzle row, and said printer controller is further programmed to supply dot data such that each of said printhead modules fires a respective segment within a predetermined segment-time, wherein at least one of said fired segments is contained in a different color channel from at least one other of said fired segments,
wherein said segment-time is a predetermined fraction of one line-time, all segments in a nozzle row being fired within one line-time, and wherein said line-time is defined as the time taken for said print medium to advance past said printhead by one line,
wherein said printer controller is programmed to supply dot data for firing sequentially a segment from each color channel on the same printhead module, such that all said segments are fired within one line-time.
2. The printhead system of claim 1 , wherein each set is a pair of nozzles, said pair consisting of one first nozzle and one corresponding second nozzle.
3. The printhead system of claim 1 , wherein said printer controller is programmed such that said first nozzles print about half of said line and said second nozzles print about half of said line.
4. The printhead system of claim 1 , wherein said printer controller is programmed such that alternate first nozzles are used to print about half of said line and alternate second nozzles are used to print about half of said line.
5. The printhead system of claim 1 , wherein each color channel comprises a pair of nozzle rows.
6. The printhead system of claim 5 , wherein said pairs of nozzle rows are transversely offset from each other.
7. The printhead system of claim 1 , wherein each set of nozzles comprises one first nozzle aligned transversely with one corresponding second nozzle, thereby allowing either of said first or second nozzles to print at the same position on said print medium.
8. The printhead system of claim 1 , wherein said printer controller is programmed to supply dot data such that a peak power requirement for said printhead is modulated.
9. The printhead system of claim 8 , wherein said peak power requirement is reduced by about 50% for printing said line, compared to printing said line using only first nozzles or only second nozzles.
10. The printhead system of claim 1 , wherein said printer controller is programmed to supply dot data such that a visual effect of misdirected ink droplets is reduced.
11. The printhead system of claim 1 , wherein said printer controller is programmed to supply dot data such that a visual effect of unknown malfunctioning nozzles is reduced.
12. The printhead system of claim 1 , wherein said color is magenta, cyan or black.
13. The printhead system of claim 1 , wherein said printhead comprises first and second magenta nozzles and first and second cyan nozzles.
14. The printhead system of claim 1 , wherein at least one nozzle row has a different peak power requirement for firing nozzles from other nozzle rows.
15. The printhead system of claim 1 , wherein said printer controller is programmed to supply dot data in accordance with a predetermined firing sequence for modulating a peak power requirement of said printhead.
16. The printhead system of claim 15 , wherein said firing sequence modulates said peak power requirement such that said peak power requirement is within 10% of an average power requirement.
17. The printhead system of claim 1 , wherein said segment-time is less than or equal to said line-time divided by the number of nozzle rows.
18. The printhead system of claim 1 , wherein the number of color channels is equal to the number of printhead modules.
19. The printhead system of claim 18 , wherein said printer controller is programmed to supply dot data such that each of said printhead modules fires a segment from a different color channel, within said predetermined segment-time.