Color adjustment determination method and information processing apparatus

• US 10,477,074 B2
• Filed: 01/23/2019
• Issued: 11/12/2019
• Est. Priority Date: 08/05/2016
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Konishi, Yohsuke, Ishii, Yoko
• Primary Examiner(s): Vo, Quang N
• Application Number:
  US16/254,784
• Publication Number:
  US 20190158705A1
• Time in Patent Office: 293 Days
• CPC Class Codes: B41J 2/21 for multi-colour printing
• CPC Class Codes: B41J 2/2146 for line print heads
• CPC Class Codes: G01J 2003/466 Coded colour; Recognition of predetermined colour; Determining proximity to predetermined colour
• CPC Class Codes: G01J 3/462 Computing operations in or between colour spaces; Colour management systems
• CPC Class Codes: G01J 3/463 Colour matching
• CPC Class Codes: G01J 3/506 measuring the colour produced by screens, monitors, displays or CRTs
• CPC Class Codes: H04N 1/6008 with primary colour signals, e.g. RGB or CMY(K)
• CPC Class Codes: H04N 1/6041 for controlling uniformity of color across image area

Abstract

A color adjustment determination method is provided that includes forming a color adjustment image on a recording medium by moving a plurality of heads including a plurality of nozzles relative to the recording medium in a relative moving direction and ejecting liquid from the plurality of heads that are arranged in an orthogonal direction orthogonal to the relative moving direction, acquiring colorimetric values of a plurality of portions of the color adjustment image formed by the plurality of heads that are arranged at different positions in the orthogonal direction, calculating a color difference between at least two portions of the plurality of portions of the color adjustment image based on the colorimetric values of the plurality of portions, and determining whether at least one of the plurality of heads that have ejected the liquid requires adjustment based on the calculated color difference.

Claims

1. A color adjustment determination method comprising:

forming a color adjustment image on a recording medium by ejecting liquid from a plurality of heads that are arranged in a line, each head of the plurality of heads including a plurality of nozzles;

acquiring colorimetric values of at least two portions of the color adjustment image formed by the plurality of heads that are arranged at different positions in the line;

calculating a color difference between the at least two portions of the color adjustment image based on the colorimetric values of the at least two portions of the color adjustment image; and

determining whether adjustment of at least one of the plurality of heads that have ejected the liquid is required based on the calculated color difference.

2. The color adjustment determination method according to claim 1, wherein

an acceptable color difference to be compared with the calculated color difference is stored in advance;

and

in determining whether adjustment of at least one of the plurality of heads is required, one of two heads of the plurality of heads that have formed two specific portions of the at least two portions of the color adjustment image is determined to require adjustment in a case where the calculated color difference between the two specific portions is greater than the acceptable color difference.

3. The color adjustment determination method according to claim 2, further comprising:

acquiring density information of the color adjustment image;

calculating a density difference between density information of a desired target color and the density information of the two specific portions of the color adjustment image that have been formed by the two heads; and

determining which head from among the two heads is to be adjusted based on the calculated density difference.

4. The color adjustment determination method according to claim 3, wherein

in determining which head from among the two heads is to be adjusted, the head among the two heads that has formed the portion from among the two specific portions having a greater density difference is determined to be the head to be adjusted.

5. The color adjustment determination method according to claim 3, wherein

the density information of the desired target color is an average value of the density information of a region of the color adjustment image that has been formed by the plurality of heads and corresponds to original image data having the same gradation information.

6. The color adjustment determination method according to claim 1, wherein

the plurality of heads form a plurality of head columns, each head column having more than one of the heads arranged in a relative moving direction;

the plurality of head columns are arranged in an orthogonal direction orthogonal to the relative moving direction; and

the plurality of head columns eject liquids in different colors from more than one of the heads included in the plurality of head columns to form an image in a color formed by the liquids in the different colors on the recording medium.

7. The color adjustment determination method according to claim 6, wherein

in forming the color adjustment image, the liquids in the different colors are ejected from more than one of the heads included in each of the plurality of head columns to form the color adjustment image in the color formed by the liquids in the different colors on the recording medium;

and

in calculating the color difference, a color difference between two portions of the color adjustment image formed by two head columns of the plurality of head columns that are arranged at different positions in the orthogonal direction is calculated.

8. The color adjustment determination method according to claim 7, wherein

an acceptable color difference to be compared with the calculated color difference is stored in advance;

and

in determining whether adjustment of at least one of the plurality of heads is required, one of the two head columns that have formed the two portions of the color adjustment image is determined to require adjustment in a case where the calculated color difference between the two portions is greater than the acceptable color difference;

the color adjustment determination method further including

acquiring a hue angle of the color adjustment image;

calculating a hue angle difference between a hue angle of a desired target color and a hue angle of each of the two portions of the color adjustment image formed by the two head columns; and

determining the head column from among the two head columns that is to be adjusted based on the calculated hue angle difference.

9. The color adjustment determination method according to claim 8, wherein

in determining which head column among the two head columns is to be adjusted, the head column from among the two head columns that has formed the portion from among the two portions of the color adjustment image having a greater hue angle difference is determined to be the head column to be adjusted.

10. The color adjustment determination method according to claim 9, further comprising:

forming, based on the hue angle, a first color checking image in which an ejection amount of a first head of the head column to be adjusted is increased and a second color checking image in which an ejection amount of a second head of the head column to be adjusted is decreased;

wherein

the first head and the second head correspond to the heads included in the head column to be adjusted that have ejected the liquids in the different colors to form the portion of the color adjustment image with the greater hue angle difference.

11. The color adjustment determination method according to claim 10, further comprising:

calculating the color difference for the first color checking image and the color difference for the second color checking image, and determining which head among the first head and the second head is to be adjusted based on the color differences calculated for the first color checking image and the second color checking image.

12. The color adjustment determination method according to claim 7, wherein

the hue angle of the desired target color is an average value of hue angles of a region of the color adjustment image that has been formed by the plurality of head columns and corresponds to original image data having the same gradation information.

13. A color adjustment determination method comprising:

acquiring colorimetric values of at least two portions of a color adjustment image formed on a recording medium by ejecting liquid from a plurality of heads that are arranged at different positions in a line, each head of the plurality of heads including a plurality of nozzles;

calculating a color difference between the at least two portions of the color adjustment image based on the colorimetric values of the at least two portions of the color adjustment image; and

determining whether adjustment of at least one of the plurality of heads that have ejected the liquid is required based on the calculated color difference.

14. A non-transitory computer-readable medium storing a program that, when executed, causes a computer to perform the color adjustment determination method according to claim 13.

15. An information processing apparatus comprising:

a processor; and

a memory storing program instructions that cause the processor to implement processes of

acquiring colorimetric values of at least two portions of a color adjustment image formed on a recording medium by ejecting liquid from a plurality of heads that are arranged at different positions in a line, each head of the plurality of heads including a plurality of nozzles;

calculating a color difference between the at least two portions of the color adjustment image based on the colorimetric values of the at least two portions of the color adjustment image; and

determining whether adjustment of at least one of the plurality of heads that have ejected the liquid is required based on the calculated color difference.