Image processing apparatus and method, dither mask set, and image recording apparatus

Patent metadata

Field	Value
Publication number	US-10814641-B2
Application number	US-201916598977-A
Country	US
Kind code	B2
Filing date	Oct 10, 2019
Priority date	Jun 21, 2017
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

Provided are an image processing apparatus, an image processing method, a dither mask set, and an image recording apparatus capable of suppressing occurrence of banding and color unevenness without productivity decrease. Halftone processing is performed with respect to image data of a first color, in a range of a part of a recording duty, using a dither mask that realizes a first nozzle jetting rate in which a nozzle jetting rate of an end part nozzle is suppressed to be smaller than a nozzle jetting rate of a central nozzle. Further, halftone processing is performed with respect to image data of a second color different from the first color, using a dither mask that realizes a second nozzle jetting rate having smaller difference between the nozzle jetting rate of the end part nozzle and the nozzle jetting rate of the central nozzle than that in the first nozzle jetting rate.

First claim

What is claimed is:

1. An image processing apparatus that generates dot data indicating a disposition pattern of dots for each color for recording an image on a recording medium, while relatively moving a recording head having a nozzle row in which a plurality of nozzles that jet, for each of a plurality of colors of ink, each ink are arranged in a sub scan direction, in a main scan direction perpendicular to the sub scan direction and the sub scan direction with respect to the recording medium, comprising:
a halftone processing unit that performs halftone processing with respect to image data of a first color among the plurality of colors, in a range of at least a part of a recording duty, using a dither mask that realizes a first nozzle jetting rate in which a nozzle jetting rate of an end part nozzle located at each of both end parts of the nozzle row is suppressed to be smaller than a nozzle jetting rate of a central nozzle located at a central part of the nozzle row, and performs halftone processing with respect to image data of a second color different from the first color among the plurality of colors, in the range of the recording duty, using a dither mask that realizes a second nozzle jetting rate having smaller difference between the nozzle jetting rate of the end part nozzle and the nozzle jetting rate of the central nozzle than that in the first nozzle jetting rate.

2. The image processing apparatus according to claim 1 ,
wherein the nozzle jetting rate of an end nozzle located at an end of the nozzle row at the first nozzle jetting rate is lower than the nozzle jetting rate of an end nozzle located at an end of the nozzle row at the second nozzle jetting rate.

3. The image processing apparatus according to claim 1 ,
wherein the first color has higher banding visibility than that of the second color.

4. The image processing apparatus according to claim 1 ,
wherein the first color has lower visibility of color unevenness in a case where the first color overlaps a different color than that of the second color.

5. The image processing apparatus according to claim 1 ,
wherein the first color has higher density than that of the second color.

6. The image processing apparatus according to claim 1 ,
wherein the first color has lower saturation than that of the second color.

7. The image processing apparatus according to claim 1 ,
wherein the nozzle jetting rate of each nozzle of the nozzle row at the second nozzle jetting rate is constant.

8. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include four colors of cyan, magenta, yellow, and black,
wherein a dither mask that realizes the first nozzle jetting rate is used for black image data, and
wherein the dither mask that realizes the second nozzle jetting rate is used for image data of at least one of cyan, magenta, or yellow.

9. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include three colors of cyan, magenta, and yellow,
wherein the dither mask that realizes the first nozzle jetting rate is used for image data of at least one of cyan or magenta, and
wherein the dither mask that realizes the second nozzle jetting rate is used for yellow image data.

10. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include two colors of cyan and magenta,
wherein the dither mask that realizes the first nozzle jetting rate is used for image data of one color among cyan and magenta, and
wherein the dither mask that realizes the second nozzle jetting rate is used for image data of the other color among cyan and magenta.

11. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include four colors of cyan, magenta, yellow, and black, and
wherein a nozzle jetting rate of each nozzle that jets black ink is set so that the nozzle jetting rate of the end nozzle located at the end of the nozzle row is lowest, compared with a nozzle jetting rate of each nozzle that jets ink of the other colors.

12. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include four colors of cyan, magenta, yellow, and black, and
wherein a nozzle jetting rate of each nozzle that jets black ink is set so that difference between the nozzle jetting rate of the end part nozzle and the nozzle jetting rate of the central nozzle is largest, compared with a nozzle jetting rate of each nozzle that jets ink of the other colors.

13. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include four colors of cyan, magenta, yellow, and black, and
wherein a nozzle jetting rate of each nozzle that jets at least one ink of cyan or magenta has a higher nozzle jetting rate of the end nozzle located at the end of the nozzle row, compared with a nozzle jetting rate of each nozzle that jets black ink.

14. The image processing apparatus according to claim 13 ,
wherein a nozzle jetting rate of each nozzle that jets cyan ink and a nozzle jetting rate of each nozzle that jets magenta ink are different from each other.

15. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include four colors of cyan, magenta, yellow, and black, and
wherein a nozzle jetting rate of each nozzle that jets ink of at least one of cyan or magenta is set so that difference between the nozzle jetting rate of the end part nozzle and the nozzle jetting rate of the central nozzle is smaller, compared with a nozzle jetting rate of each nozzle that jets black ink.

16. The image processing apparatus according to claim 14 ,
wherein a nozzle jetting rate of each nozzle that jets cyan ink and a nozzle jetting rate of each nozzle that jets magenta ink are different from each other.

17. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include yellow, and
wherein a nozzle jetting rate of each nozzle that jets yellow ink is set so that the nozzle jetting rate of the end nozzle located at the end of the nozzle row is largest, compared with a nozzle jetting rate of each nozzle that jets ink of the other colors.

18. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include yellow, and
wherein a nozzle jetting rate of each nozzle that jets yellow ink is set so that difference between the nozzle jetting rate of the end part nozzle and the nozzle jetting rate of the central nozzle is smallest, compared with a nozzle jetting rate of each nozzle that jets ink of the other colors.

19. The image processing apparatus according to claim 1 ,
wherein the plurality of colors include yellow, and
wherein a dither mask applied to yellow image data is a dither mask that realizes a uniform nozzle jetting rate in which a nozzle jetting rate of each nozzle that jets yellow ink is constant.

20. The image processing apparatus according to claim 1 , further comprising:
a dither mask storage section that stores plural kinds of dither masks including the dither mask that realizes the first nozzle jetting rate and the dither mask that realizes the second nozzle jetting rate; and
a dither mask selecting section that selects a dither mask to be used for the halftone processing from the plural kinds of dither masks, in accordance with a color type of image data that is a target of the halftone processing.

21. The image processing apparatus according to claim 1 ,
wherein the halftone processing unit

Assignees

• Fujifilm Corp

Inventors

• Katsuyama Kimito

Classifications

• B41J2/52

  Arrangement for printing a discrete number of tones, not covered by group B41J2/205, e.g. applicable to two or more kinds of printing or marking process (B41J2/525 takes precedence) · CPC title

• G06K15/1876

  Decreasing spatial resolution; Dithering · CPC title

• B41J2/465

  using masks, e.g. light-switching masks · CPC title

• B41J2/15

  for serial printing · CPC title

• B41J2/512

  Adjustment of the dot disposition by adjustment of the arrangement of the dot printing elements of a print head, e.g. nozzles, needles · CPC title