Image forming apparatus

Patent metadata

Field	Value
Publication number	US-10915994-B2
Application number	US-202016887510-A
Country	US
Kind code	B2
Filing date	May 29, 2020
Priority date	Aug 30, 2018
Publication date	Feb 9, 2021
Grant date	Feb 9, 2021

Abstract

An image forming apparatus includes an image forming device to form a correction image, an image density detector to detect image densities of a plurality of areas in the correction image, and circuitry to correct an image formation condition of the image forming device based on detected image densities of the plurality of areas. The circuitry replaces a detected image density of an area of interest selected from the plurality of areas with an average value of detected image densities of two or more areas including adjacent areas adjacent to the area of interest and corrects the image formation condition of the image forming device based on the detected image densities of the plurality of areas after replacement when a difference between the detected image density of the area of interest and at least one of the detected image densities of the adjacent areas exceeds a predetermined threshold.

First claim

What is claimed is:

1. An image forming apparatus comprising:
an image forming device configured to form a correction image;
an image density detector configured to detect image densities of a plurality of areas in the correction image; and
circuitry configured to correct an image formation condition of the image forming device based on calculated correction amounts of the plurality of areas calculated from the image densities of the plurality of areas detected by the image density detector,
the circuitry configured to:
execute replacement processing to replace a calculated correction amount of an area of interest selected from the plurality of areas with an average value of calculated correction amounts of two or more areas including adjacent areas adjacent to the area of interest; and
correct the image formation condition of the image forming device based on the calculated correction amounts of the plurality of areas after the replacement processing,
when a difference between the calculated correction amount of the area of interest and at least one of the calculated correction amounts of the adjacent areas exceeds a predetermined threshold.

2. The image forming apparatus according to claim 1 ,
wherein the circuitry executes the replacement processing when either of the following conditional expressions expressed by Expression 5 or Expression 6 is satisfied:
C ( n )− C ( n− 1)< C _ L and C ( n+ 1)− C ( n )>0   Expression 5; or

C ( n )− C ( n− 1)<0 and C ( n+ 1)− C ( n )> C _ U   Expression 6,

where C(n) is the calculated correction amount of the area of interest, C(n−1) and C(n+1) are the calculated correction amounts of the adjacent areas, and C_L and C_U are predetermined thresholds including the predetermined threshold.

3. The image forming apparatus according to claim 2 ,
wherein the circuitry calculates the predetermined thresholds C_L and C_U based on a standard deviation of the calculated correction amounts of part or all of the plurality of areas before the replacement processing.

4. The image forming apparatus according to claim 1 ,
wherein the circuitry performs the replacement processing when either of the following conditional expressions expressed by Expression 7 or Expression 8 is satisfied:
C ( n )− C ( n− 1)> C _ U and C ( n+ 1)− C ( n )<0   Expression 7; or

C ( n )− C ( n− 1)>0 and C ( n+ 1)− C ( n )< C _ L   Expression 8,

where C(n) is the calculated correction amount of the area of interest, C(n−1) and C(n+1) are the calculated correction amounts of the adjacent areas, and C_L and C_U are predetermined thresholds including the predetermined threshold.

Assignees

• Yamamura Hiroki
• Yasuda Makoto
• Kobayashi Kazumi
• Ricoh Co Ltd

Inventors

• Yamamura Hiroki
• Yasuda Makoto
• Kobayashi Kazumi

Classifications

• G06T7/44

  using image operators, e.g. filters, edge density metrics or local histograms · CPC title

• G03G15/5062 Primary

  by measuring the characteristics of an image on the copy material · CPC title

• G03G15/556

  for toner consumption, e.g. pixel counting, toner coverage detection or toner density measurement · CPC title

• B41J2/473

  using multiple light beams, wavelengths or colours · CPC title

• G03G2215/00755

  of sheet toner density · CPC title