# US 9,870,524 B2 · Image forming apparatus and computer program product for performing color adjustment based on color shift and tendency for color shift over time

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- Number: US 9,870,524 B2
- Document ID: US9870524B2
- Status: Granted
- Kind: B2
- Application number: 14/933,791
- Filed: 2015-11-05
- Published: 2016-12-29
- Granted: 2018-01-16
- Earliest claimed: 2015-06-24
- Assignees: Fuji Xerox Co., Ltd.
- Applicants: Fuji Xerox Co., Ltd.
- Inventors: Takuhiro Togashi
- Web page: https://patentgrep.com/patent/US9870524B2

## CPC

- G06K 15/1878: {Adjusting colours (image colour correction or control for documents in general H04N1/60)}
- G06K 15/027: {Test patterns and calibration (arrangements for controlling or analysing printing mechanisms of typewriters or selective printing units B41J29/393 takes precedence; colour correction using test pattern analysis in general H04N1/6033)}
- H04N 1/00005: {relating to image data}
- H04N 1/00015: {Reproducing apparatus}
- H04N 1/00023: {Colour systems}
- H04N 1/00031: {Testing, i.e. determining the result of a trial (H04N1/00029 takes precedence; using test signals for transmission mode changing H04N2201/33371)}
- H04N 1/00045: {using a reference pattern designed for the purpose, e.g. a test chart}
- H04N 1/00055: {automatically on a periodic basis}
- H04N 1/00087: {Setting or calibrating (picture signal circuits H04N1/40)}
- H04N 1/6036: {involving periodic tests or tests during use of the machine}
- H04N 1/6044: {involving a sensor integrated in the machine or otherwise specifically adapted to read the test pattern}
- G06K 15/102: {using ink jet print heads}
- G06K 15/14: by electrographic printing, e.g. xerography; by magnetographic printing {(G06K15/12 takes precedence)}
- H04N 1/29: involving production of an electrostatic intermediate picture
- H04N 2201/0094: Multifunctional device, i.e. a device capable of all of reading, reproducing, copying, facsimile transception, file transception
- G06K: GRAPHICAL DATA READING (image or video recognition or understanding G06V); PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Provided is an image forming apparatus including an image forming section that periodically forms a color calibration image which is used for color adjustment along with an image on a recording material, a color information obtaining section that periodically obtains color information of the color calibration image which is formed on the recording material before color adjustment which is periodically performed, and a color adjusting section that, based on plural pieces of the color information that is obtained by the color information obtaining section, performs color adjustment on an image formed by the image forming section such that a difference between a color of an image which is supposed to be output and a color of an image which is output is reduced by a next color adjustment.

## Claims

### Claim 1

An image forming apparatus comprising:
a processor configured to execute:
an image forming section configured to periodically form a plurality of color calibration images which is used for color adjustment on a recording material;
a color information obtaining section configured to obtain a first color information of a first color calibration image which is formed on the recording material at a first time and obtain a second color information of a second color calibration image which is formed on the recording material at a second time, the first color information and the second color information being obtained before color adjustment which is periodically performed; and
a color adjusting section configured to:
determine a first correction value based on a color shift from a reference value, based on the second color information that is obtained by the color information obtaining section;
determine a temporal change value based on the first color information obtained at the first time and the second color information obtained at the second time, the temporal change value indicating a tendency of the color shift in relation to a change in time;
determine a second corrected value based on the temporal change value;
generate a third correction value generated by adding the first correction value and the second correction value; and
perform color adjustment on an image formed by the image forming section based on the a third correction value, such that a difference between a color of an image which is supposed to be output and a color of an image which is output is adjusted based on both the color shift and the tendency of the color shift.

### Claim 2 (depends on 1)

The image forming apparatus according to claim 1,
wherein the color adjusting section is further configured to perform color adjustment with using color information that is obtained by the color information obtaining section and previous color information that corresponds to the color information.

### Claim 3 (depends on 1)

The image forming apparatus according to claim 1,
wherein the color adjusting section is further configured to determine a fourth correction value based on previous color information that corresponds to the color information, and perform color adjustment based on the third correction value and the fourth correction value.

### Claim 4 (depends on 1)

The image forming apparatus according to claim 1,
wherein the color adjusting section is further configured to perform color adjustment on an image with a value that is smaller than a predetermined value in a stepwise manner when a difference between the color of an image formed by the image forming section before color adjustment and the color of an image formed after color adjustment exceeds a predetermined value.

### Claim 5 (depends on 2)

The image forming apparatus according to claim 2,
wherein the color adjusting section is further configured to perform color adjustment on an image with a value that is smaller than a predetermined value in a stepwise manner when a difference between the color of an image formed by the image forming section before color adjustment and the color of an image formed after color adjustment exceeds a predetermined value.

### Claim 6 (depends on 3)

The image forming apparatus according to claim 3,
wherein the color adjusting section is further configured to perform color adjustment on an image with a value that is smaller than a predetermined value in a stepwise manner when a difference between the color of an image formed by the image forming section before color adjustment and the color of an image formed after color adjustment exceeds a predetermined value.

### Claim 7

A non-transitory computer readable medium storing a program causing a computer to execute a process for image formation, the process comprising:
periodically forming a plurality of color calibration images which is used for color adjustment on a recording material;
obtaining a first color information of a first color calibration image which is formed on the recording material at a first time and obtaining a second color information of a second color calibration image which is formed on the recording material at a second time, the first color information and the second color information being obtained before color adjustment which is periodically performed;
determining a first correction value based on a color shift from a reference value based on the second color information that is obtained;
determining, a temporal change value based on the first color information obtained at the first time and the second color information obtained at the second time, the temporal change value indicating a tendency of the color shift in relation to a change in time;
determining a second corrected value based on the temporal change value;
generating a third correction value generated by adding the first correction value and the second correction value; and
performing color adjustment on an image formed based on the third correction value such that a difference between a color of an image which is supposed to be output and a color of an image which is output is adjusted based on both the color shift and the tendency of the color shift.