US 12,189,319 B2
Image forming apparatus to perform phase matching control to match phases of image-density cycle fluctuations
Keita Sone, Tokyo (JP); Tomohide Takenaka, Kanagawa (JP); and Naoki Ohta, Kanagawa (JP)
Assigned to RICOH COMPANY, LTD., Tokyo (JP)
Filed by Keita Sone, Tokyo (JP); Tomohide Takenaka, Kanagawa (JP); and Naoki Ohta, Kanagawa (JP)
Filed on May 30, 2023, as Appl. No. 18/203,067.
Claims priority of application No. 2022-087782 (JP), filed on May 30, 2022.
Prior Publication US 2023/0384725 A1, Nov. 30, 2023
Int. Cl. G03G 15/00 (2006.01); G03G 15/02 (2006.01); G03G 15/043 (2006.01); G03G 15/06 (2006.01)
CPC G03G 15/5041 (2013.01) [G03G 15/0266 (2013.01); G03G 15/043 (2013.01); G03G 15/065 (2013.01); G03G 2215/00042 (2013.01); G03G 2215/0164 (2013.01)] 8 Claims
OG exemplary drawing
 
1. An image forming apparatus, comprising:
a plurality of image formers each including:
Y, M, C, and B (Yellow, Magenta, Cyan and Black) image bearers;
a plurality of chargers to uniformly charge each of the image bearers; and
a plurality of developer bearers corresponding to the image bearers to attach developer to an electrostatic latent image on each of the image bearers to form a visible image;
an irradiator to illuminate each of the image bearers charged by the chargers to form the electrostatic latent image on each of the image bearers; and
circuitry configured to:
acquire an image-density cycle fluctuation in the visible image for each of the plurality of image formers; and
perform image-density fluctuation-reduction control to cyclically change image forming conditions to reduce the image-density cycle fluctuation for each of the plurality of image formers on basis of the image-density cycle fluctuation of each of the plurality of image formers acquired by the circuitry,
the circuitry being further configured to perform:
first fluctuation-reduction control to correct a developing bias applied to the developer bearers, which is one of the image forming conditions, to cancel an image-density cycle fluctuation of a high-density image pattern acquired by the circuitry;
second fluctuation-reduction control to, after the first fluctuation-reduction control, correct a charging bias applied to the chargers, which is one of the image forming conditions, to cancel an image-density cycle fluctuation of a first low-density image pattern acquired by the circuitry; and
third fluctuation-reduction control to, after the first fluctuation-reduction control and the second fluctuation-reduction control, correct an exposure light amount of the irradiator, which is one of the image forming conditions, to cancel an image-density cycle fluctuation of a second low-density image pattern acquired by the circuitry, the high-density image pattern being higher in image density than each of the first low-density image pattern and the second low-density image pattern,
wherein:
the circuitry is configured to perform phase matching control which matches phases of image-density cycle fluctuations of the plurality of image formers on a recording medium, based on the image-density cycle fluctuations of the plurality of image formers acquired by the circuitry,
the circuitry rotates the Y, M, and C image bearers to match the phases of the Y, M, and C image-density cycle fluctuations, and
colors subjected to the phase matching control include the Y, M, and C colors.