Developer unit for an image forming apparatus

1. A developer unit for an image forming apparatus, comprising:

a developer device having a developer roller, which rotatably carries a developer agent on a surface thereof, a supplier roller, which supplies the developer agent to the developer roller, and a restricting member, which scrapes the surface of the developer roller to restrict thickness of the developer agent on the surface of the developer roller;

a developer agent container, which contains the developer agent; and

a plurality of conveyers, including a first conveyer and a second conveyer, to convey the developer agent in an axial direction of the supplier roller, both of the first conveyer and the second conveyer being disposed between the supplier roller and the developer agent container along a vertical direction of the image forming apparatus,

wherein a distance between the first conveyer and the supplier roller is substantially equal to a distance between the second conveyer and the supplier roller,

wherein the second conveyer is arranged along a circumference of the supplier roller and arranged in parallel with the first conveyer,

wherein the developer device is formed to have a first room to accommodate the first conveyer, a second room to accommodate the second conveyer, and a partition wall to divide the first room and the second room; and

wherein the developer device is configured to have a level of the developer agent in the first room to be lower than a level of the developer agent in the second room when the developer roller, the supplier roller, and the first and second conveyers are driven.

2. The developer unit according to claim 1 ,

wherein the restricting member is arranged in a position higher than the supplier roller;

wherein the developer agent container is arranged adjacent to the developer device in the developer unit; and

wherein the first conveyer is arranged in an upper position with respect to the supplier roller and adjacent to the restricting member.

3. The developer unit according to claim 1 ,

wherein the developer device is formed to have a feeding opening, through which the developer agent in the developer agent container is supplied to the second room;

wherein the partition wall of the developer device is formed to have a communication opening, through which the developer agent in the second room is transferred to the first room, in a downstream side of a developer agent conveying flow for the second conveyer;

wherein the first room of the developer device is formed to have a collecting opening, through which the developer agent in the first room is returned to the developer agent container, in a downstream side of a developer agent conveying flow for the first conveyer; and

wherein the communication opening is formed in an upper position with respect to the collecting opening.

4. The developer unit according to claim 1 ,

wherein the developer device is formed to have:

a first feeding opening, through which the developer agent is supplied from the developer agent container to the first room; and

a second feeding opening, through which the developer agent is supplied from the developer agent container to the second room,

wherein a size of the second feeding opening is larger than a size of the first feeding opening.

5. The developer unit according to claim 1 ,

wherein the developer device is formed to have:

a first collecting opening, through which the developer agent in the first room conveyed by the first conveyer to a downstream side for the first conveyer is returned to the developer agent container; and

a second collecting opening, through which the developer agent in the second room conveyed by the second conveyer to a downstream side for the second conveyer is returned to the developer agent container;

wherein a size of the second collecting opening is smaller than a size of the first collecting opening.

6. The developer unit according to claim 1 ,

wherein the developer device is formed to have a feeding opening, through which the developer agent in the developer agent container is supplied to the second room;

wherein the partition wall of the developer device is formed to have a communication opening, through which the developer agent in the second room is transferred to the first room, in a downstream side of a developer agent conveying flow for the second conveyer;

wherein the first room of the developer device is formed to have a collecting opening, through which the developer agent in the first room is returned to the developer agent container, in a downstream side of a developer agent conveying flow for the first conveyer; and

wherein the first conveyer has greater capability to convey the developer agent than capability of the second conveyer to convey the developer agent.

7. The developer unit according to claim 6 ,

wherein the first conveyer conveys a greater amount of developer agent than an amount of the developer agent to be conveyed by the second conveyer per unit of time.

8. The developer unit according to claim 1 ,

wherein the developer device is formed to have:

a first feeding opening, through which the developer agent is supplied from the developer agent container to the first room;

a second feeding opening, through which the developer agent is supplied from the developer agent container to the second room;

a first collecting opening, through which the developer agent in the first room conveyed by the first conveyer to a downstream side for the first conveyer is returned to the developer agent container; and

a second collecting opening, through which the developer agent in the second room conveyed by the second conveyer to a downstream side for the second conveyer is returned to the developer agent container;

wherein the first conveyer has greater capability to convey the developer agent than capability of the second conveyer to convey the developer agent.

9. The developer unit according to claim 8 ,

wherein the first conveyer conveys a greater amount of developer agent than an amount of the developer agent to be conveyed by the second conveyer per unit of time.