Image forming apparatus
AssigneeCanon Kabushiki Kaisha
InventorYoshiro Tsukada
Life of this patent
Estimating the term…
Abstract
A developing sleeve is configured to be driven separately from a conveyance screw facing a developer discharge port for discharging a developer. When the driving speed of the developing sleeve is changed, the rotational speed ratio of conveyance members respectively disposed in a developing chamber and an agitation chamber is changed accordingly.
Claims6
An image forming apparatus capable of executing a first mode in which an image forming speed is a first speed, and a second mode in which an image forming speed is a second speed lower than the first speed, the image forming apparatus comprising:
- an image bearing member rotatably disposed, and configured to bear an image;
- a developer bearing member rotatably disposed, and configured to bear a developer containing toner and a carrier to develop a latent image formed on the image bearing member;
- a first chamber configured to supply the developer to the developer bearing member at a position facing the developer bearing member;
- a second chamber connected with the first chamber to form a circulation path for circulating the developer between the first and second chambers, and configured to collect the developer from the developer bearing member at a position facing the developer bearing member;
- a partition wall separating the first and the second chambers;
- a discharge port configured to discharge the developer in a developing device;
- a first conveyance member rotatably disposed in the first chamber so as to face the discharge port, and configured to convey the developer in the first chamber,
- wherein the first conveyance member has no blade in an area corresponding to the discharge port, or a diameter of blades in the area is smaller than that of blades in front and rear areas in a conveyance direction;
- a second conveyance member rotatably disposed in the second chamber, and configured to convey the developer in the second chamber;
- a first drive source configured to drive the first conveyance member;
- a second drive source configured to drive the second conveyance member;
- and
- a control unit configured to control the first and the second drive sources so that, when the first mode is changed to the second mode, a speed change amount of the first conveyance member is smaller than a speed change amount of the second conveyance member.
An image forming apparatus capable of executing a first mode in which an image forming speed is a first speed, and a second mode in which an image forming speed is a second speed lower than the first speed, the image forming apparatus comprising:
- an image bearing member rotatably disposed, and configured to bear an image;
- a developer bearing member rotatably disposed, and configured to bear a developer containing toner and a carrier to develop a latent image formed on the image bearing member;
- a first chamber configured to supply the developer to the developer bearing member at a position facing the developer bearing member;
- a second chamber connected with the first chamber to form a circulation path for circulating the developer between the first and second chambers, and configured to collect the developer from the developer bearing member at a position facing the developer bearing member;
- a partition wall separating the first and the second chambers;
- a discharge port configured to discharge the developer in a developing device;
- a first conveyance member rotatably disposed in the first chamber, and configured to convey the developer in the first chamber;
- a second conveyance member rotatably disposed in the second chamber so as to face the discharge port, and configured to convey the developer in the second chamber,
- wherein the second conveyance member has no blade in an area corresponding to the discharge port, or a diameter of blades in the area is smaller than that of blades in front and rear areas in a conveyance direction;
- a first drive source configured to drive the first conveyance member;
- a second drive source configured to drive the second conveyance member;
- and
- a control unit configured to control the first and the second drive sources so that, when the first mode is changed to the second mode, a speed change amount of the second conveyance member is smaller than a speed change amount of the first conveyance member.
Dependencies are inferred from the claim text.