Developing device having gears with moveable positions

1. A developing device comprising:

a developing housing that supports a developer carrier; and

a developer cartridge comprising:

a cartridge housing that is configured to accommodate developer;

an agitator that is provided in the cartridge housing and is configured to agitate the developer by a driving force;

a transmission gear that is configured to transmit the driving force to the agitator and the transmission gear is configured to rotate about a rotation axis of the transmission gear; and

an agitator gear that is provided on a rotating shaft of the agitator and meshes with the transmission gear,

wherein the developing housing comprises a moving gear that is movable between a meshing position in which the moving gear meshes with the transmission gear and a spaced-apart position in which the moving gear is spaced apart from the meshing position,

wherein the moving gear is configured to transmit the driving force from the transmission gear to the agitator, and

wherein the rotation axis of the transmission gear is pivotable about the rotating shaft of the agitator.

2. The developing device according to claim 1 , wherein:

the transmission gear comprises gear teeth on an end face thereof in a perpendicular direction to a longitudinal direction of the developer carrier;

the developer cartridge is attachable to and detachable from the developing housing along the perpendicular direction; and

the moving gear comprises gear teeth formed on an end face thereof in the perpendicular direction.

3. The developing device according to claim 1 ,

wherein the moving gear moves to the meshing position when the driving force is transmitted thereto, and

wherein the moving gear moves to the spaced-apart position when the transmission of the driving force is stopped.

4. The developing device according to claim 1 ,

wherein the developing housing further comprises a guide portion for guiding the moving gear between the meshing position and the spaced-apart position.

5. The developing device according to claim 4 ,

wherein the guide portion comprises a hole for supporting the moving gear, the hole extending continuously so as to guide the moving gear between the meshing position and the spaced-apart position.

6. The developing device according to claim 4 ,

wherein the guide portion comprises a groove for supporting the moving gear, the groove extending continuously so as to guide the moving gear between the meshing position and the spaced-apart position.

7. The developing device according to claim 1 , further comprising:

a pressing gear that is configured to mesh with the moving gear to transmit the driving force to the moving gear and is configured to press the moving gear to the meshing position when transmitting the driving force to the moving gear.

8. The developing device according to claim 1 ,

wherein the transmission gear is provided outside of the cartridge housing.

9. The developing device according to claim 1 ,

wherein the cartridge housing further comprises:

a first housing; and

a second housing rotatably accommodated in the first housing,

wherein the transmission gear is provided between the first housing and the second housing.

10. The developing device according to claim 1 , wherein the developer cartridge further comprises:

a supporting member for supporting the transmission gear movably with respect to the agitation gear in a meshing state between the transmission gear and the agitation gear.

11. The developing device according to claim 1 , further comprising:

an actuating member that is configured to move the moving gear to the spaced-apart position when the transmission of the driving force is stopped.

12. The developing device according to claim 11 ,

wherein the actuating member comprises an elastic body for pressing the moving gear to the spaced-apart position.