| CPC G03G 15/0216 (2013.01) [G03G 9/097 (2013.01); G03G 15/065 (2013.01); G03G 15/5008 (2013.01)] | 16 Claims |
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1. An image forming apparatus comprising:
an image bearing member configured to rotate;
a charging member configured to contact with the image bearing member and to rotate while forming a charging portion, the charging member charging a surface of the image bearing member at the charging portion;
a charging voltage applying portion configured to apply charging voltage to the charging member;
an exposure unit configured to expose the surface of the image bearing member charged by the charging member;
a developer bearing member configured to bear developer, face the image bearing member at a development portion, and supply the developer to the surface of the image bearing member;
a developing voltage applying portion configured to apply developing voltage to the developer bearing member;
a transfer member configured to transfer the developer, which has been supplied to the surface of the image bearing member at a transfer portion, onto a transferred member;
a transfer voltage applying portion configured to apply transfer voltage to the transfer member;
a cleaning member configured to contact the image bearing member at a cleaning portion which is formed on a downstream side of the transfer portion and on an upstream side of the charging portion in a rotating direction of the image bearing member, wherein the cleaning member is a cleaning blade abutting against the image bearing member and configured to remove the developer before being transferred to the transfer portion; and
a control portion configured to control the charging voltage applying portion, the developing voltage applying portion, and the transfer voltage applying portion,
wherein the control portion is further configured to execute
a first operation to move the developer from a surface of the charging member to the surface of the image bearing member by controlling the charging voltage applying portion;
a second operation to move the developer from the surface of the image bearing member to the developer bearing member by controlling the charging voltage applying portion and the developing voltage applying portion; and
a third operation to supply the developer to the cleaning portion by controlling the charging voltage applying portion, the developing voltage applying portion, and the transfer voltage applying portion, wherein
in the first operation, between the charging member and the image bearing member, the control portion controls the charging voltage applying portion so as to generate
a first potential difference that generates an electrostatic force to move developer, which is charged to an opposite polarity to a normal charging polarity of the developer, from the charging member to the image bearing member, wherein
in the second operation, between the image bearing member and the developer bearing member, the control portion controls the developing voltage applying portion so as to generate
a second potential difference, that generates an electrostatic force to move developer, which is charged to an opposite polarity opposite to the normal charging polarity of the developer, from the image bearing member to the developer bearing member;
in the third operation, the control portion controls to apply the transfer voltage having a polarity corresponding to the normal charging polarity of the developer by the transfer voltage applying portion while the developer passes through the transfer portion; and
wherein a region on the surface of the image bearing member where the second potential difference is generated in the second operation includes a region where the first potential difference is generated in the first operation.
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