Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorsMasaru Ohno, Shinji Katagiri, Yuji Kawaguchi
Life of this patent
Estimating the term…
Abstract
A control unit is provided which controls at least one of a first power supply unit (a secondary transfer power supply connected to a secondary transfer roller) and a second power supply unit (high-voltage power supplies connected to a conductive brush and a conductive roller) so that a current supplied to a primary transfer region from a beginning of primary transfer until a beginning of secondary transfer has a magnitude larger than a magnitude of a current supplied to the primary transfer region from a beginning of image formation until the beginning of the primary transfer.
Claims13
An image forming apparatus comprising:
- an image bearing member on which a toner image is formed;
- an intermediate transfer member that is endless and rotatable, the intermediate transfer member being disposed in contact with the image bearing member and forming a primary transfer region between the intermediate transfer member and the image bearing member, the toner image being primarily transferred, at the primary transfer region, to the intermediate transfer member;
- a transfer member disposed in contact with the intermediate transfer member and forming a secondary transfer region between the transfer member and the intermediate transfer member;
- a first power supply unit connected to the transfer member;
- a charging member provided downstream of the secondary transfer region in a rotating direction of the intermediate transfer member and upstream of the primary transfer region to charge a residual toner remaining on the intermediate transfer member;
- a second power supply unit connected to the charging member;
- and
- a control unit controlling at least one of the first power supply unit and the second power supply unit,
- wherein the control unit controls at least one of the first power supply unit and the second power supply unit so that a current supplied to the primary transfer region from a beginning of primary transfer until a beginning of secondary transfer has a magnitude larger than a magnitude of a current supplied to the primary transfer region from a beginning of image formation until the beginning of the primary transfer, and
- the first power supply unit and the second power supply unit pass a current from the transfer member and the charging member to the image bearing member via the intermediate transfer belt to carry out the primary transfer.
Dependencies are inferred from the claim text.