# US 7,465,005 B2 · Printer controller with dead nozzle compensation

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- Number: US 7,465,005 B2
- Document ID: US7465005B2
- Status: Granted
- Kind: B2
- Application number: 11/442,131
- Filed: 2006-05-30
- Published: 2006-09-28
- Granted: 2008-12-16
- Earliest claimed: 2002-12-02
- Assignees: Silverbrook Research Pty Ltd
- Inventors: Simon Robert Walmsley; Richard Thomas Plunkett
- Web page: https://patentgrep.com/patent/US7465005B2

## CPC

- G06F 21/73: by creating or determining hardware identification, e.g. serial numbers
- B41J 2/04505: {aiming at correcting alignment}
- B41J 2/04508: {aiming at correcting other parameters}
- B41J 2/0451: {for detecting failure, e.g. clogging, malfunctioning actuator}
- B41J 2/04528: {aiming at warming up the head}
- B41J 2/04541: {Specific driving circuit}
- B41J 2/04543: {Block driving}
- B41J 2/04563: {detecting head temperature; Ink temperature}
- B41J 2/04573: {Timing; Delays}
- B41J 2/04586: {controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type}
- G06F 21/554: {involving event detection and direct action}
- G06F 21/57: Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
- G06F 21/575: {Secure boot}
- G06F 21/64: Protecting data integrity, e.g. using checksums, certificates or signatures
- G06F 21/71: to assure secure computing or processing of information
- G06F 21/74: operating in dual or compartmented mode, i.e. at least one secure mode
- G06F 21/78: to assure secure storage of data (address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00)
- H03K 5/1252: Suppression or limitation of noise or interference (specially adapted for transmission systems H04B15/00, H04L25/08)
- H04N 1/405: Halftoning, i.e. converting the picture signal of a continuous-tone original into a corresponding signal showing only two levels
- B41J 2202/20: Modules
- Y10S 707/99933: Query processing, i.e. searching
- Y10S 707/99939: Privileged access
- Y10T 29/49401: Fluid pattern dispersing device making, e.g., ink jet
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A printer controller able to compensate for inoperative or dead nozzles in a printhead. The printhead includes a plurality of sets of nozzles for printing a corresponding plurality of channels of dot data. The printhead is operated or controlled by the printer controller able to determine one or more operative nozzles capable of printing a dot on print media near a position at which the inoperative nozzle would have printed a dot had it been operative. The printer controller may also compensate for an inoperative nozzle in the printhead by using color redundancy.

## Claims

### Claim 1

A printer controller for compensating for an inoperative nozzle in a printhead segmented as a bi-lithic printhead, the printhead including a plurality of nozzles associated with each pixel to be printed, the printer controller is operative to control one or more operative nozzles associated with the same pixel as the inoperative nozzle to increase the amount of printing substance expelled by the one or more operative nozzles and wherein the printer controller is further operative to:
[a] form a compressed bi-level layer for a given print line intended for the bi-lithic printhead;
[b] expand the compressed bi-level layer;
[c] composite the bi-level layer to produce bi-level dots;
[d] determine which combination of one or more available operative nozzles near the inoperative nozzle reduces perceived error in an image that the dot data forms part of, the determination being performed on the basis of a color model;
[e] map the dot data intended for the inoperative nozzle to the combination of one or more operative nozzles; and,
[f] pass resultant bi-level channel dot data to the bi-lithic printhead.

### Claim 2 (depends on 1)

The printer controller as claimed in claim 1, wherein the printer controller compensates for the inoperative nozzle by increasing the amount of printing substance expelled by one or more operative nozzles expelling printing substance with a color substantially similar to the color expelled by the inoperative nozzle.

### Claim 3 (depends on 1)

The printer controller as claimed in claim 1, wherein there are six nozzles associated with each pixel and the amount of printing substance expelled by each nozzle is bi-level.

### Claim 4 (depends on 1)

The printer controller as claimed in claim 1, wherein information indicating inoperative nozzles is stored in a table.

### Claim 5 (depends on 4)

The printer controller as claimed in claim 4, wherein the table is updated by performing an inoperative nozzle test including the steps of:
running a printhead nozzle test sequence;
converting inoperative nozzle information into an inoperative nozzle table; and,
writing the inoperative nozzle table to a memory of the printer controller.

### Claim 6 (depends on 1)

The printer controller as claimed in claim 1, wherein the inoperative nozzle is associated with a black print channel, and wherein dot data intended for the inoperative nozzle is mapped into a plurality of operative nozzles associated with the same pixel as the inoperative nozzle in other color channels to produce a process black output substantially at a location on print media where the inoperative nozzle would have deposited a dot of a black printing substance in accordance with the dot data.

### Claim 7 (depends on 1)

The printer controller as claimed in claim 1, wherein the increased amounts of printing substance expelled by the one or more operative nozzles forms a pixel with a color substantially similar to the color expelled by the inoperative nozzle.