Powder recovery device and image forming apparatus

1. A powder recovery device comprising:

a powder storage container that stores powder recovered from a recovery port; and

at least two powder conveying members (i) that are disposed on upper and lower sides of the recovery port interposed therebetween in the powder storage container, (ii) that are disposed in a longitudinal direction of the powder storage container, and (iii) that are set so that the amount of powder conveyed near the recovery port is larger than the amount of powder conveyed to a back side which is on the opposite side of the recovery port in the longitudinal direction.

2. The powder recovery device according to claim 1 , wherein

the at least two powder conveying members include rotating shafts which are rotationally driven, and conveying blades which are formed in a spiral shape on an outer periphery of the rotating shafts, and

the amount of powder conveyed by the respective powder conveying members in axial directions thereof is set by forming the conveying blades only at a part of the rotating shafts in the axial directions.

3. The powder recovery device according to claim 1 , wherein

the at least two powder conveying members are set so that the amount of powder conveyed by the powder conveying member, which is disposed on the upper side of the recovery port, is larger than the amount of powder conveyed by the powder conveying member, which is disposed on the lower side of the recovery port.

4. The powder recovery device according to claim 1 , wherein

the powder conveying member, which is disposed on the upper side of the recovery port, of the at least two powder conveying members includes:

a first conveying blade that is provided in an axial direction of a rotating shaft of the powder conveying member in an area corresponding to the recovery port; and

at least a plurality of second and third conveying blades that are provided adjacent to the first conveying blade through bladeless areas, where conveying blades are not formed, interposed therebetween.

5. The powder recovery device according to claim 4 , wherein

the powder conveying member, which is disposed on the lower side of the recovery port, of the at least two powder conveying members includes:

a first conveying blade that corresponds to a first conveying blade of the powder conveying member disposed on the upper side of the recovery port and that is set to be shorter than the first conveying blade of the powder conveying member disposed on the upper side; and

a second conveying blade that is provided from an intermediate portion of a second conveying blade of the powder conveying member disposed on the upper side, over an end of a third conveying blade of the powder conveying member disposed on the upper side.

6. The powder recovery device according to claim 1 , wherein

the powder conveying member, which is disposed on the lower side of the recovery port, of the at least two powder conveying members includes:

a first conveying blade that corresponds to a first conveying blade of the powder conveying member disposed on the upper side of the recovery port and that is set to be shorter than the first conveying blade of the powder conveying member disposed on the upper side; and

a second conveying blade that is provided from an intermediate portion of a second conveying blade of the powder conveying member disposed on the upper side, over an end of a third conveying blade of the powder conveying member disposed on the upper side.

7. The powder recovery device according to claim 1 , wherein

the at least two powder conveying members include a plurality of grooves which extend in an axial direction of the at least two powder conveying members and is formed in a circumferential direction on outer peripheral surfaces of one end portions of a rotating shafts of the powder conveying members.

8. The powder recovery device according to claim 1 , wherein

at least one or more cutout portions, which extend in an axial direction of the powder conveying members, are formed in a circumferential direction at bearing members which support the rotating shafts of the at least two powder conveying members.

9. A powder recovery device comprising:

a powder storage container that stores powder recovered from a recovery port; and

at least two powder conveying members (i) that are disposed on upper and lower sides of the recovery port interposed therebetween in the powder storage container, (ii) that are disposed in a longitudinal direction of the powder storage container, (iii) that are set so that the amount of powder conveyed near the recovery port is larger than the amount of powder conveyed by a conveying unit for conveying powder to the recovery port from outside of the powder storage container, and (iv) that are set so that the amount of powder conveyed to a back side which is on the opposite side of the recovery port in the longitudinal direction is smaller than the amount of powder conveyed to the recovery port.

10. An image forming apparatus comprising:

a plurality of image forming sections that forms images having different colors;

a powder conveying section that conveys powder recovered from the plurality of image forming sections to a powder storage container;

the powder storage container that stores powder recovered from a recovery port; and

at least two powder conveying members (i) that are disposed on upper and lower sides of the recovery port interposed therebetween in the powder storage container, (ii) that are disposed in a longitudinal direction of the powder storage container, and (iii) that are set so that the amount of powder conveyed near the recovery port is larger than the amount of powder conveyed to a back side which is on the opposite side of the recovery port in the longitudinal direction of the powder storage container and is larger than the amount of powder conveyed by the powder conveying section.