US 12,117,755 B2
Control device, image forming apparatus, image forming method, and storage medium
Kanji Ubukata, Kanagawa (JP); Koji Kiryu, Tokyo (JP); Masashi Kasamai, Kanagawa (JP); Jumpei Yamaguchi, Kanagawa (JP); Masahiro Ashikawa, Kanagawa (JP); and Nagisa Nakamura, Shizuoka (JP)
Assigned to Ricoh Company, Ltd., Tokyo (JP)
Filed by Kanji Ubukata, Kanagawa (JP); Koji Kiryu, Tokyo (JP); Masashi Kasamai, Kanagawa (JP); Jumpei Yamaguchi, Kanagawa (JP); Masahiro Ashikawa, Kanagawa (JP); and Nagisa Nakamura, Shizuoka (JP)
Filed on Oct. 13, 2022, as Appl. No. 18/046,207.
Claims priority of application No. 2021-176789 (JP), filed on Oct. 28, 2021; and application No. 2022-140572 (JP), filed on Sep. 5, 2022.
Prior Publication US 2023/0134616 A1, May 4, 2023
Int. Cl. G03G 15/00 (2006.01); G03G 15/01 (2006.01)
CPC G03G 15/5025 (2013.01) [G03G 15/01 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A control device for controlling a rotation of a plurality of rotatable image bearers corresponding to different colors respectively, the control device comprising circuitry configured to:
receive a density of a toner image formed on each of the plurality of image bearers, the density detected by a toner density sensor;
receive a rotation phase of each of the plurality of image bearers relative to a rotation origin of the each of the plurality of the image bearers, the rotation phase detected by a rotation-phase detector;
determine a first density unevenness of the toner image occurring according to a rotation of a first image bearer for a first color among the plurality of rotatable image bearers, based on the rotation phase of the first image bearer relative to the rotation origin and a variation in the density of the toner image formed on the first image bearer;
determine a second density unevenness of the toner image occurring according to a rotation of a second image bearer for a second color among the plurality of image bearers, based on the rotation phase of the second image bearer relative to the rotation origin and a variation in the density of the toner image formed on the second image bearer;
correct the rotation phase of the first image bearer based on the first density unevenness and a rotation speed of the first image bearer;
correct the rotation phase of the second image bearer based on the second density unevenness and a rotation speed of the second image bearer;
control the rotation speeds of the first image bearer and the second image bearer to be a specified rotation speed; and
start detecting the rotation phase of each of the plurality of image bearers after a difference between each of the rotation speeds of the first image bearer and the second image bearer and the specified rotation speed falls within a specified range.