Developer guide device and image forming apparatus including the same

1. A developer guide device comprising:

a conveying pipe portion configured to guide a developer in a predetermined conveyance direction;

a light-emitting portion configured to emit light into an interior of the conveying pipe portion through a light projection window provided in a peripheral wall of the conveying pipe portion;

a light-receiving portion capable of receiving light from the interior of the conveying pipe portion through a light reception window provided in the peripheral wall of the conveying pipe portion;

a cleaning mechanism including a cleaning member configured to receive a predetermined drive force to be displaced thereby to come into contact with inner surfaces of the light projection window and the light reception window to clean the inner surfaces; and

a conveying member configured to be rotationally driven about a rotational axis thereof thereby to convey the developer having passed through the conveying pipe portion, wherein

the cleaning mechanism further includes a power transmission portion configured to transmit rotational power of the conveying member to the cleaning member to displace the cleaning member, and

the power transmission portion converts the rotational power of the conveying member to power in a direction parallel to the conveyance direction and transmits the power to the cleaning member to cause the cleaning member to reciprocate in the direction parallel to the conveyance direction in a state where the cleaning member is in contact with the inner surfaces.

2. The developer guide device according to claim 1 , wherein the power transmission portion includes:

an eccentric shaft portion provided at a position eccentric from a rotation center of the conveying member and configured to rotate around the rotation center with rotation of the conveying member; and

a connection portion connected at one end thereof to the cleaning member and at another end thereof to the eccentric shaft portion and configured to receive a force from the eccentric shaft portion along with rotation of the eccentric shaft portion to reciprocate in the direction parallel to the conveyance direction.

3. The developer guide device according to claim 2 , wherein

the light projection window and the light reception window are provided in the peripheral wall of the conveying pipe portion and at positions opposed to each other,

the cleaning member includes: a first contact member provided in corresponding relation to the inner surface of the light projection window and configured to come into contact with the inner surface of the light projection window to clean the inner surface; and a second contact member provided in corresponding relation to the inner surface of the light reception window and configured to come into contact with the inner surface of the light reception window to clean the inner surface, and

the connection portion includes: a first support portion configured to support the first contact member at a side including the light projection window; and a second support portion configured to support the second contact member at a side including the light reception window.

4. The developer guide device according to claim 2 , wherein the cleaning member is a sheet-like elastic member which has elasticity and is contactable with the inner surfaces in a bent state.

5. The developer guide device according to claim 4 , wherein

the conveying pipe portion has a cylindrical shape,

the connection portion includes a base which has a bottom surface connected to the eccentric shaft portion and has a circular truncated cone shape which widens from the bottom surface toward an upstream side in the conveyance direction of the developer in the conveying pipe portion, and

the cleaning member is mounted on an outer circumferential surface of the connection portion and at positions corresponding to the light projection window and the light reception window, respectively, and includes a projection portion projecting upward from an upper edge portion of the connection portion.

6. The developer guide device according to claim 1 , wherein the cleaning mechanism displaces the cleaning member in the direction parallel to the conveyance direction, between a facing position at which the cleaning member faces the inner surfaces and a retracting position at which the cleaning member has retracted from the facing position.

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

a determination portion configured to determine whether the conveying pipe portion is in an empty state where the developer is not present in the conveying pipe portion, on the basis of an amount of the light received by the light-receiving portion; and

a drive control portion configured to control a predetermined driving source to supply the drive force for causing the cleaning mechanism to perform a cleaning operation, if the determination portion determines that the conveying pipe portion is not in the empty state.

8. The developer guide device according to claim 7 , wherein after the cleaning mechanism is caused to perform the cleaning operation, if the determination portion determines that the conveying pipe portion is in the empty state, the drive control portion stops the cleaning operation of the cleaning mechanism.

9. An image forming apparatus comprising:

the developer guide device according to claim 1 ;

a developer storage portion configured to store the developer therein and capable of supplying the developer to the conveying pipe portion of the developer guide device; and

a developing portion configured to supply the developer conveyed by the developer guide device, to a photosensitive body thereby to develop an electrostatic latent image.