Developing device and image forming apparatus
AssigneeSharp Kabushiki Kaisha
InventorsShigeki Hayashi, Takafumi Nagai
Life of this patent
Estimating the term…
Abstract
A developing device comprises a first and a second developer conveyance path. A first conveyance member is provided in the first developer conveyance path in a freely rotatable manner and has a helical blade. A developing roller supplies the developer in the first developer conveyance path to a photoconductor drum. A developer collection path guides two-component developer left on a surface of the developing roller from the first developer conveyance path. A developer surface adjustment window comprises a predetermined level for allowing excess developer exceeding the level of the window to be guided from the first developer conveyance path to the developer collection path.
Claims13
A developing device comprising:
- a first developer conveyance path and a second developer conveyance path for conveying and circulating a two-component developer including a toner and a magnetic carrier;
- a first communicating path for guiding the two-component developer in the first developer conveyance path to the second developer conveyance path;
- a second communicating path for guiding the two-component developer in the second developer conveyance path to the first developer conveyance path;
- a first conveyance member being provided in the first developer conveyance path in a freely rotatable manner and having a helical blade for conveying the two-component developer in one direction, the helical blade having helical pitches decreasing toward a downstream side from an upstream side of a developer conveyance direction;
- a second conveyance member being provided in the second developer conveyance path in a freely rotatable manner for conveying the two-component developer in one direction;
- a developing roller for bearing and supplying the two-component developer in the first developer conveyance path to a photoconductor drum;
- a developer collection path for guiding the two-component developer left on a surface of the developing roller after the developer is supplied to the photoconductor drum in a direction away from the first developer conveyance path;
- a third developer conveyance path for containing the two-component developer guided to the developer collection path and conveying the developer in one direction;
- a third conveyance member being provided in the third developer conveyance path in a freely rotatable manner;
- a third communicating path for guiding the two-component developer in the third developer conveyance path to the second developer conveyance path;
- and
- a developer surface adjustment window being provided between the first developer conveyance path and the developer collection path and having a predetermined level for allowing excess developer exceeding the level of the window to be guided from the first developer conveyance path to the developer collection path.
Dependencies are inferred from the claim text.