Developer transport apparatus and image forming apparatus

1. A developer transport apparatus comprising:

a first developer-containing unit that contains a developer;

a first developer transport member disposed in the first developer-containing unit, the first developer transport member transporting the developer in a first direction;

a second developer transport member disposed downstream from the first developer transport member in the first direction, the second developer transport member transporting the developer in the first direction and having a lower capability of transporting the developer than that of the first developer transport member;

a developer discharge unit disposed in the first developer-containing unit, the developer discharge unit discharging the developer transported by the second developer transport member from the first developer-containing unit; and

a second developer-containing unit that contains the developer discharged from the developer discharge unit; wherein

the first developer transport member and the second developer transport member rotate in the same axis;

the first developer transport member and the second developer transport member are overlapped in a direction of transporting the developer in the first developer-containing unit; and

the second developer transport member is disposed more downstream than a downstream end portion of the first developer transport member in the first direction of the first developer transport member.

2. A developer transport apparatus comprising:

a first developer-containing unit that contains a developer;

a first developer transport member disposed in the first developer-containing unit, the first developer transport member comprising a first transport unit having a first rotation diameter and rotating so as to transport the developer in a first direction;

a second developer transport member disposed downstream from the first developer transport member in the first direction, the second developer transport member comprising a second transport unit having a second rotation diameter that is smaller than the first rotation diameter, the second transport unit rotating so as to transport the developer in the first direction;

a developer discharge unit disposed in the first developer-containing unit, the developer discharge unit discharging the developer transported by the second developer transport member from the first developer-containing unit; and

a second developer-containing unit that contains the developer discharged from the developer discharge unit; wherein

the second developer transport member is disposed more downstream than a downstream end portion of the first developer transport member in the first direction of the first developer transport member.

3. A developer transport apparatus comprising:

a first developer-containing unit that contains a developer;

a first developer transport member disposed in the first developer-containing unit, the first developer transport member transporting the developer in a first direction;

a second developer transport member disposed downstream from the first developer transport member in the first direction, the second developer transport member transporting the developer in the first direction and having a lower capability of transporting the developer than that of the first developer transport member;

a developer discharge unit disposed in the first developer-containing unit, the developer discharge unit discharging the developer transported by the second developer transport member from the first developer-containing unit; and

a second developer-containing unit that contains the developer discharged from the developer discharge unit, the first developer transport member having such a shape that enables the developer retained between the first developer transport member and the second developer transport member to flow back; wherein

the second developer transport member is disposed more downstream than a downstream end portion of the first developer transport member in the first direction of the first developer transport member.

4. A developer transport apparatus comprising:

a first developer-containing unit that contains a developer;

a first developer transport member disposed in the first developer-containing unit, the first developer transport member comprising a first transport unit having a first rotation diameter and rotating so as to transport the developer in a first direction;

a second developer transport member disposed downstream from the first developer transport member in the first direction, the second developer transport member comprising a second transport unit having a second rotation diameter that is smaller than the first rotation diameter, the second transport unit rotating so as to transport the developer in the first direction;

a developer discharge unit disposed in the first developer-containing unit, the developer discharge unit discharging the developer transported by the second developer transport member from the first developer-containing unit; and

a second developer-containing unit that contains the developer discharged from the developer discharge unit, the first developer transport member being a rotational transport member comprising a wire formed into a helical form; wherein

the first developer transport member and the second developer transport member rotate in the same axis;

an inner diameter of the first developer transport member is larger than an outer diameter of the second developer transport member; and

the second developer transport member is disposed more downstream than a downstream end portion of the first developer transport member in the first direction of the first developer transport member.

5. The developer transport apparatus according to claim 3 , further comprising a retention unit disposed in the developer discharge unit, the retention unit retaining the developer.

6. The developer transport apparatus according to claim 4 , further comprising a retention unit disposed in the developer discharge unit, the retention unit retaining the developer.

7. The developer transport apparatus according to claim 3 , wherein the first developer transport member and the second developer transport member are overlapped in a direction of transporting the developer in the first developer-containing unit.

8. The developer transport apparatus according to claim 4 , wherein the first developer transport member and the second developer transport member are overlapped in a direction of transporting the developer in the first developer-containing unit.

9. An image forming apparatus comprising:

a developer supply vessel containing a developer and being detachable from the image forming apparatus;

a developer discharging unit that discharges the developer to outside of the developer supply vessel;

a first developer-containing unit that contains a developer;

a first developer transport member disposed in the first developer-containing unit, the first developer transport member transporting the developer in a first direction;

a second developer transport member disposed downstream from the first developer transport member in the first direction, the second developer transport member transporting the developer in the first direction and having a lower capability of transporting the developer than that of the first developer transport member;

a developer discharge unit disposed in the first developer-containing unit, the developer discharge unit discharging the developer transported by the second developer transport member from the first developer-containing unit;

a second developer-containing unit that contains the developer discharged from the developer discharge unit;

a detector disposed in the first developer-containing unit, the detector detecting an amount of the developer at a position of the first developer-containing unit;

a controller that controls the discharging of the developer by the developer discharging unit, depending on a detection result of the detector; and

a developing device containing at least a n toner and a carrier, the developing device developing a toner image on an image retainer by using the developer discharged from the developer discharge unit; wherein

the first developer transport member and the second developer transport member rotate in the same axis;

the first developer transport member and the second developer transport member are overlapped in a direction of transporting the developer in the first developer-containing unit; and

the second developer transport member is disposed more downstream than a downstream end portion of the first developer transport member in the first direction of the first developer transport member.

10. An image forming apparatus comprising:

a developer supply vessel containing a developer and being detachable from the image forming apparatus;

a developer discharging unit that discharges the developer to outside of the developer supply vessel;

a first developer-containing unit that contains a developer;

a first developer transport member disposed in the first developer-containing unit, the first developer transport member comprising a first transport unit having a first rotation diameter and rotating so as to transport the developer in a first direction;

a second developer transport member disposed downstream from the first developer transport member in the first direction, the second developer transport member comprising a second transport unit having a second rotation diameter that is smaller than the first rotation diameter, the second transport unit rotating so as to transport the developer in the first direction;

a developer discharge unit disposed in the first developer-containing unit, the developer discharge unit discharging the developer transported by the second developer transport member from the first developer-containing unit; and

a second developer-containing unit that contains the developer discharged from the developer discharge unit;

a detector disposed in the first developer-containing unit, the detector detecting an amount of the developer at a position of the first developer-containing unit;

a controller that controls the discharging of the developer by the developer discharging unit, depending on a detection result of the detector; and

a developing device containing at least a toner and a carrier, the developing device developing a toner image on an image retainer by using the developer discharged from the developer discharge unit; wherein

the second developer transport member is disposed more downstream than a downstream end portion of the first developer transport member in the first direction of the first developer transport member.

11. The image forming apparatus according to claim 9 , further comprising a manual paper feeder capable of being disposed inside the apparatus main body.

12. The image forming apparatus according to claim 10 , further comprising a manual paper feeder capable of being disposed inside the apparatus main body.