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US 2021/0373453 A1Published application
Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorKohei Okayasu
Life of this patent
Estimating the term…
Abstract
A region of an image bearing member that comes into contact with a recording material at a nip in a state in which the recording material is held by the nip is a first region, and a region of the image bearing member that does not come into contact with the recording material at the nip in a state in which the recording material is not held by the nip is a second region. A controller controls to apply a first developing voltage to a developer bearing member when the first region in which a first surface potential has been formed faces a developer bearing member and apply a second developing voltage smaller than an absolute value of the first developing voltage to the developer bearing member when the second region in which a second surface potential has been formed faces the developer bearing member.
Claims19
An image forming apparatus comprising:
- an image bearing member that is rotatable;
- a charging member that charges a surface of the image bearing member at a charging portion;
- an exposure portion that exposes the image bearing member to form an electrostatic latent image on the surface of the image bearing member;
- a developer bearing member that bears a developer charged to have a normal polarity and supplies the developer to the electrostatic latent image formed on the surface of the image bearing member to form a developer image on the surface of the image bearing member;
- a transfer member that comes into contact with the image bearing member to form a nip and transfers the developer image onto a recording material conveyed to the nip;
- a charging voltage application portion that applies a charging voltage to the charging member;
- a developing voltage application portion that applies a developing voltage to the developer bearing member;
- a transfer voltage application portion that applies a transfer voltage to the transfer member;
- and
- a controller that controls the charging voltage application portion, the developing voltage application portion, and the transfer voltage application portion,
- wherein, when a region of the image bearing member that comes into contact with the recording material at the nip in a state in which the transfer voltage is applied to the transfer member and the recording material is held by the nip is assumed as a first region and a region of the image bearing member that does not come into contact with the recording material at the nip in a state in which the transfer voltage is applied to the transfer member and the recording material is not held by the nip is assumed as a second region,
- the controller controls to apply a first developing voltage to the developer bearing member when the first region in which a first surface potential has been formed at the charging portion faces the developer bearing member and apply a second developing voltage smaller than an absolute value of the first developing voltage to the developer bearing member when the second region in which a second surface potential has been formed at the charging portion faces the developer bearing member after the recording material passes through the nip.
9 more elements
An image forming apparatus comprising:
- an image bearing member that is rotatable;
- a charging member that charges a surface of the image bearing member at a charging portion;
- an exposure portion that exposes the image bearing member to form an electrostatic latent image on the surface of the image bearing member;
- a developer bearing member that bears a developer charged to have a normal polarity and supplies the developer to the electrostatic latent image formed on the surface of the image bearing member to form a developer image on the surface of the image bearing member;
- a transfer member that comes into contact with the image bearing member to form a nip and transfers the developer image onto a recording material conveyed to the nip;
- a charging voltage application portion that applies a charging voltage to the charging member;
- a developing voltage application portion that applies a developing voltage to the developer bearing member;
- a transfer voltage application portion that applies a transfer voltage to the transfer member;
- and
- a controller that controls the charging voltage application portion, the developing voltage application portion, and the transfer voltage application portion,
- wherein, when a region of the image bearing member that comes into contact with the recording material at the nip in a state in which the transfer voltage is applied to the transfer member and the recording material is held by the nip is assumed as a first region, a region of the image bearing member that does not come into contact with the recording material at the nip in a state in which the transfer voltage is applied to the transfer member and the recording material is not held by the nip is assumed as a second region, and a region of the image bearing member that is positioned between the first region and the second region and comes into contact with the recording material at the nip in a state in which the transfer voltage is applied to the transfer member and the recording material is held by the nip is assumed as a third region,
- the controller controls to apply a first developing voltage to the developer bearing member when the first region in which a first surface potential has been formed at the charging portion faces the developer bearing member and apply a second developing voltage smaller than an absolute value of the first developing voltage to the developer bearing member when the second region in which a second surface potential has been formed at the charging portion faces the developer bearing member after the recording material passes through the nip,
- a developing potential formed in the developer bearing member overshoots when the third region in which a third surface potential has been formed at the charging portion faces the developer bearing member and when the second developing voltage is switched to the first developing voltage, and
- an absolute value of the developing potential due to an overshoot of the developing potential is larger than an absolute value of the developing potential formed when the first developing voltage is applied to the developer bearing member.
11 more elements
Dependencies are inferred from the claim text.