US 12,092,969 B2
Image-forming apparatus having charging potential control during non-image forming operation
Jun Hara, Kanagawa (JP); and Taichi Sato, Kanagawa (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Mar. 16, 2023, as Appl. No. 18/185,036.
Claims priority of application No. 2022-045083 (JP), filed on Mar. 22, 2022.
Prior Publication US 2023/0305423 A1, Sep. 28, 2023
Int. Cl. G03G 15/02 (2006.01); G03G 21/00 (2006.01); G03G 15/00 (2006.01)
CPC G03G 15/0266 (2013.01) [G03G 15/0225 (2013.01); G03G 21/0064 (2013.01); G03G 15/50 (2013.01)] 11 Claims
OG exemplary drawing
 
1. An image-forming apparatus configured to execute an image-forming operation to form an image on a recording material, the image-forming apparatus comprising:
an image bearing member;
a driving portion configured to rotationally drive the image bearing member;
a charging member to be in contact with a surface of the image bearing member to form a charging portion, the charging member being configured to charge the surface of the image bearing member at the charging portion;
a developing member configured to supply the surface of the image bearing member with developer;
a charging voltage application portion configured to apply a charging voltage to the charging member; and
a control unit configured to control the driving portion and the charging voltage application portion,
wherein the control unit controls the image-forming operation and a non-image-forming operation different from the image-forming operation to be executable, the non-image-forming operation being an operation to apply the charging voltage to the charging member in a state where the image bearing member is rotated, and
wherein, in the non-image-forming operation, the control unit executes the following control processing:
i) not discharging electric charge between the charging member and the image bearing member and applying a first charging voltage having a first polarity with respect to a surface potential on the surface of the image bearing member to the charging member;
ii) after performing the processing of i), not discharging electric charge between the charging member and the image bearing member and applying a second charging voltage to the charging member, the second charging voltage having a polarity opposite to the first polarity with respect to the surface potential; and
iii) after performing the processing of ii), controlling a third charging voltage having a second polarity with respect to the surface potential to be applied to the charging member and controlling a fourth charging voltage having a polarity opposite to the second polarity with respect to the surface potential to be applied to the charging member, and controlling electric charge to be discharged between the charging member and the image bearing member in a case where at least one of the third charging voltage and the fourth charging voltage is applied as the charging voltage.