US 2019/0101859 A1Published application

Image forming apparatus

AssigneeCanon Kabushiki Kaisha

InventorsTaisuke Minagawa, Yusaku Iwasawa

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Abstract

Provided is an image forming apparatus, including: an image bearing member on which an electrostatic latent image is formed; an image bearing member charging unit which applies image bearing member charging voltage; a developer bearing member to which developing voltage for developing the electrostatic latent image on the image bearing member is applied and which bears and transports a developer; a primary transfer unit which transfers a developer image on the image bearing member to an intermediate transfer member; and a charging member which charges a developer on the intermediate transfer member, the developer image being first primarily transferred and then secondarily transferred to a recording material, wherein the image forming apparatus operates in: a first mode in which a residual developer on the intermediate transfer member after the secondary transfer is electrostatically removed from the intermediate transfer member; and a second mode.

Claims25

Dependent claims

An image forming apparatus, comprising:

an image bearing member on which an electrostatic latent image is formed;
an image bearing member charging unit which applies image bearing member charging voltage for charging the image bearing member;
a developer bearing member to which developing voltage is applied and which bears and transports a developer in order to develop the electrostatic latent image formed on the image bearing member;
a primary transfer unit which primarily transfers a developer image developed on the image bearing member to an intermediate transfer member;
and
a charging member which applies voltage to the intermediate transfer member so that a developer on the intermediate transfer member can be charged,
the developer image being first primarily transferred to the intermediate transfer member by the primary transfer unit and then secondarily transferred to a recording material from the intermediate transfer member to form an image on the recording material, wherein
the image forming apparatus operates in:
a first mode in which a developer remaining on the intermediate transfer member after the developer image is secondarily transferred to the recording material is charged by the charging member and electrostatically removed from the intermediate transfer member;
and
a second mode in which the intermediate transfer member is driven in a state in which an absolute value of voltage applied to the charging member is smaller than in the first mode, and in which the developer bearing member and the image bearing member are in contact with each other, and
a difference in potential between developing voltage and image bearing member charging voltage in the second mode differs from a difference in potential between developing voltage and image bearing member charging voltage in the first mode.

9 more elements

An image forming apparatus, comprising:

an image bearing member on which an electrostatic latent image is formed;
a developer bearing member which bears a developer for developing the electrostatic latent image formed on the image bearing member;
a developer control member which controls an amount of the developer on the developer bearing member;
an intermediate transfer member which is provided with a transfer unit and in which a developer image developed on the image bearing member is primarily transferred to the transfer unit due to the transfer unit and the image bearing member coming into contact with each other and the developer image is further secondarily transferred from the transfer unit to a recording material due to the transfer unit and the recording material coming into contact with each other;
a charging member which charges a developer on the intermediate transfer member;
and
a cleaning unit capable of executing a cleaning mode in which a developer remaining on the intermediate transfer member after being secondarily transferred from the intermediate transfer member to the recording material is charged by the charging member and removed from the intermediate transfer member, wherein
when executing the cleaning mode during a non-image formation period in which an image is not formed, the cleaning unit reduces an absolute value of voltage applied to the charging member and, at the same time, sets a difference in potential ΔVb of voltage applied to the developer control member relative to voltage applied to the developer bearing member to a value on a side of a same polarity as a normal charging polarity of the developer, as compared to when executing the cleaning mode during an image formation period in which an image is formed.

5 more elements

An image forming apparatus, comprising:

an image bearing member on which an electrostatic latent image is formed;
a developer bearing member which bears a developer for developing the electrostatic latent image formed on the image bearing member;
a developer supplying member which supplies the developer to the developer bearing member;
an intermediate transfer member which is provided with a transfer unit and in which a developer image developed on the image bearing member is primarily transferred to the transfer unit due to the transfer unit and the image bearing member coming into contact with each other and the developer image is further secondarily transferred from the transfer unit to a recording material due to the transfer unit and the recording material coming into contact with each other;
a charging member which charges a developer on the intermediate transfer member;
and
a cleaning unit capable of executing a cleaning mode in which a developer remaining on the intermediate transfer member after being secondarily transferred from the intermediate transfer member to the recording material is charged by the charging member and removed from the intermediate transfer member, wherein
when executing the cleaning mode during a non-image formation period in which an image is not formed, the cleaning unit reduces an absolute value of voltage applied to the charging member and, at the same time, sets a difference in potential ΔVs of voltage applied to the developer supplying member relative to voltage applied to the developer bearing member to a value on a side of an opposite polarity to a normal charging polarity of the developer, as compared to when executing the cleaning mode during an image formation period in which an image is formed.

5 more elements

An image forming apparatus, comprising:

an image bearing member on which an electrostatic latent image is formed after a surface of the image bearing member is charged;
a developer bearing member which bears a developer for developing the electrostatic latent image formed on the image bearing member;
an intermediate transfer member which is provided with a transfer unit and in which a developer image developed on the image bearing member is primarily transferred to the transfer unit due to the transfer unit and the image bearing member coming into contact with each other and the developer image is further secondarily transferred from the transfer unit to a recording material due to the transfer unit and the recording material coming into contact with each other;
a transfer member for primarily transferring the developer image from the image bearing member to the intermediate transfer member;
a charging member which charges a developer on the intermediate transfer member;
and
a cleaning unit capable of executing a cleaning mode in which a developer remaining on the intermediate transfer member after being secondarily transferred from the intermediate transfer member to the recording material is charged by the charging member and removed from the intermediate transfer member, wherein
when executing the cleaning mode during a non-image formation period in which an image is not formed, the cleaning unit reduces an absolute value of voltage applied to the charging member and, at the same time, varies an absolute value of a difference in potential Vback between voltage applied to the developer bearing member and surface voltage prior to formation of an electrostatic latent image on the charged image bearing member, as compared to when executing the cleaning mode during an image formation period in which an image is formed.

5 more elements

Dependencies are inferred from the claim text.