Inkjet printing apparatus and inkjet printing method

Patent metadata

Field	Value
Publication number	US-10293620-B2
Application number	US-201715657512-A
Country	US
Kind code	B2
Filing date	Jul 24, 2017
Priority date	Aug 9, 2016
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

An inkjet printing apparatus uses a printing head including a plurality of nozzle arrays each including a plurality of nozzles arrayed in a first direction, the nozzle arrays being arranged in a second direction. A compensating unit compensates for an ejection failure of a defective nozzle by causing a compensating nozzle to eject ink to a predetermined pixel area in a case where the print data corresponding to the defective nozzle indicates ink ejection to the predetermined pixel area. The compensating unit determines the compensating nozzle such that the compensating nozzle satisfies both a first condition that the compensating nozzle is not a defective nozzle and a second condition that the print data indicates that nozzles belonging to the nozzle array including the compensating nozzle do not eject ink to a pixel area corresponding to N pixels (N is a positive integer) around the predetermined pixel area in the first direction.

First claim

What is claimed is:

1. An inkjet printing apparatus using a printing head including a plurality of nozzle arrays each including a plurality of nozzles configured to eject ink and arrayed in a first direction, the nozzle arrays being arranged in a second direction intersecting with the first direction, to print an image on a print medium while relatively moving at least one of the printing head and the print medium in the second direction, the inkjet printing apparatus comprising one or more processors and one or more computer-readable media functioning as:
a generation unit configured to generate a plurality of items of print data corresponding to the plurality of the nozzle arrays, respectively, by allocating print data indicating whether or not to eject ink to each pixel on the print medium to the plurality of the nozzle arrays;
an acquisition unit configured to acquire information on a defective nozzle included in the printing head; and
a compensating unit configured to compensate for an ejection failure of the defective nozzle by causing a compensating nozzle different from the defective nozzle to eject ink to a pixel area, on the print medium, to which ink is indicated to be ejected onto by the defective nozzle,
wherein the compensating unit determines the compensating nozzle such that the following conditions are satisfied:
i) a first condition that the compensating nozzle is not a defective nozzle, and
ii) a second condition that nozzles belonging to the nozzle array including the compensating nozzle do not eject ink to a pixel area corresponding to N pixels (N is a positive integer) around any pixel area to which ink is indicated to be ejected onto by the defective nozzle in the first direction.

2. The inkjet printing apparatus according to claim 1 , wherein the compensating unit determines the compensating nozzle such that the following condition is further satisfied:
iii) a third condition that the compensating nozzle does not eject ink to M pixels (M is a positive integer) around any pixel area which ink is indicated to be ejected onto by the defective nozzle in the second direction.

3. The inkjet printing apparatus according to claim 1 , wherein the compensating unit determines a plurality of compensating nozzle candidates from the plurality of nozzle arrays such that the first and second conditions are satisfied, and selects one of the compensating nozzle candidates as the compensating nozzle.

4. The inkjet printing apparatus according to claim 3 , wherein the compensating unit selects one of the compensating nozzle candidates as the compensating nozzle based on priority information which defines priorities for the compensating nozzle.

5. The inkjet printing apparatus according to claim 4 , wherein several of the nozzle arrays are located along the first direction and other nozzle arrays are located at different positions with respect to the first direction, and
the priority information defines the priorities for the compensating nozzle such that a nozzle in a nozzle array located along the first direction with a nozzle array including the defective nozzle has a higher priority.

6. The inkjet printing apparatus according to claim 4 , wherein the priority information defines the priorities for the compensating nozzle such that a nozzle in a nozzle array close to a nozzle array including the defective nozzle with respect to the second direction has a higher priority.

7. The inkjet printing apparatus according to claim 1 , wherein after the compensating unit compensates for the ejection failure, the print data is defined such that a drive rate of each nozzle is less than 1/(N+1).

8. An inkjet printing apparatus using a printing head including a plurality of nozzle arrays each including a plurality of nozzles configured to eject ink and arrayed in a first direction, the nozzle arrays being arranged in a second direction intersecting with the first direction, to print an image on a print medium while relatively moving at least one of the printing head and the print medium in the second direction, the inkjet printing apparatus comprising one or more processors and one or more computer-readable media functioning as:
a generation unit configured to generate a plurality of items of print data corresponding to the plurality of the nozzle arrays, respectively, by allocating print data indicating whether or not to eject ink to each pixel on the print medium to any of the plurality of the nozzle arrays;
an acquisition unit configured to acquire information on a defective nozzle included in the printing head; and
a compensating unit configured to compensate for an ejection failure of the defective nozzle by causing a compensating nozzle different from the defective nozzle to eject ink to a pixel area, on the print medium, to which ink is indicated to be ejected onto by the defective nozzle,
wherein the compensating unit determines the compensating nozzle such that the following conditions are satisfied:
i) a first condition that the compensating nozzle is not a defective nozzle, and
ii) a second condition that the compensating nozzle does not eject ink to M pixels (M is a positive integer) around any pixel area to which ink is indicated to be ejected onto by the defective nozzle in the second direction.

9. The inkjet printing apparatus according to claim 8 , wherein the compensating unit determines a plurality of compensating nozzle candidates from the plurality of nozzle arrays such that the first and second conditions are satisfied, and selects one of the compensating nozzle candidates as the compensating nozzle.

10. The inkjet printing apparatus according to claim 9 , wherein the compensating unit selects one of the compensating nozzle candidates as the compensating nozzle based on priority information which defines priorities for the compensating nozzle.

11. The inkjet printing apparatus according to claim 10 , wherein several of the nozzle arrays are located along the first direction and the other nozzle arrays are located at different positions with respect to the first direction, and
the priority information defines the priorities for the compensating nozzle such that a nozzle in a nozzle array located along the first direction with a nozzle array including the defective nozzle has a higher priority.

12. The inkjet printing apparatus according to claim 10 , wherein the priority information defines the priorities for the compensating nozzle such that a nozzle in a nozzle array close to a nozzle array including the defective nozzle with respect to the second direction has a higher priority.

13. The inkjet printing apparatus according to claim 8 , wherein after the compensating unit compensates for the ejection failure, the print data is defined such that a drive rate of each nozzle is less than 1/(M+1).

14. An inkjet printing method using a printing head including a plurality of nozzle arrays each including a plurality of nozzles configured to eject ink and arrayed in a first direction, the nozzle arrays being arranged in a second direction intersecting with the first direction, to print an image on a print medium while relatively moving at least one of the printing head and the print medium in the second direction, the inkjet printing method comprising the steps of:
generating a plurality of items of print data corresponding to the plurality of the nozzle arrays, respectively, by allocating print data indicating whether or not to eject ink to each pixel on the print medium to the plurality of the nozzle arrays;
acquiring information on a defective nozzle included in the printing head; and
compensating for an ejection failure

Assignees

• Canon Kk

Inventors

• Murayama Yoshiaki
• Kitai Satoshi
• Umezawa Masahiko

Classifications

• B41J2/2139 Primary

  Compensation for malfunctioning nozzles creating dot place or dot size errors (generating single droplets or particles on demand by pressure, e.g. electromechanical transducers B41J2/045) · CPC title

• B41J2/04525

  reducing occurrence of cross talk · CPC title

• B41J2/2107

  characterised by the ink properties (supplying ink in a solid state B41J2/17593) · CPC title

• B41J2/15

  for serial printing · CPC title

• B41J2/2146

  for line print heads · CPC title