Developer supplier operable in developer supply pipe and electrophotographic image forming apparatus using the same

1. A developer supplier for delivering a developer in a supply pipe, the developer supplier comprising:

a rotation shaft including:

a first rotation shaft that is rigid, and

a second rotation shaft that is flexible, has a smaller bending strength than the first rotation shaft, and connectable to the first rotation shaft; and

a spiral wing formed around the rotation shaft, wherein at least a portion of the spiral wing formed around the second rotation shaft is flexible.

2. The developer supplier of claim 1 , wherein the first rotation shaft includes a rigid core, and

the second rotation shaft and the at least the portion of the spiral wing are formed by insert injection molding using the rigid core as an insertion material to be flexible.

3. The developer supplier of claim 1 , wherein the spiral wing includes a rigid spiral wing formed around the first rotation shaft and a flexible spiral wing formed around the second rotation shaft,

the first rotation shaft and the rigid spiral wing are integrally formed by plastic molding and form a rigid member, and

the second rotation shaft and the flexible spiral wing are formed on the rigid member by double injection molding.

4. The developer supplier of claim 1 , wherein the spiral wing includes a rigid spiral wing formed around the first rotation shaft and a flexible spiral wing formed around the second rotation shaft,

the first rotation shaft and the rigid spiral wing are integrally formed by insert injection molding using a metal rigid core as an insertion material and forming a rigid member, and

the second rotation shaft and the flexible spiral wing are formed on the rigid member by double injection molding.

5. The developer supplier of claim 1 , wherein the first rotation shaft includes a rigid core,

the second rotation shaft includes a flexible core that has a smaller bending strength than the rigid core, and

the spiral wing is formed around the rigid core and the flexible core by insert injection molding to be flexible.

6. The developer supplier of claim 1 , wherein the spiral wing includes a rigid spiral wing integrally formed around the first rotation shaft, and a flexible spiral wing integrally formed around the second rotation shaft, and

the first rotation shaft and the second rotation shaft are connectable to each other via a connector.

7. The developer supplier of claim 1 , wherein the spiral wing includes a rigid spiral wing integrally formed around the first rotation shaft, and a flexible spiral wing integrally formed around the second rotation shaft, and

an insertion hole is provided in an end of the first rotation shaft, and an end of the second rotation shaft is inserted into the insertion hole.

8. The developer supplier of claim 1 , wherein the supply pipe has a multi-curvature structure.

9. An image forming apparatus comprising:

a developer cartridge;

a developing device including a photoconductor;

a buffer unit between the developer cartridge and the developing device and including an inlet portion into which a developer is fed from the developer cartridge, and an outlet portion;

a supply pipe configured to connect the outlet portion to the developing device; and

developer supplier for delivering a developer in a supply pipe, the developer supplier including:

a rotation shaft including:

a first rotation shaft that is rigid, and

a second rotation shaft that is flexible, has a smaller bending strength than the first rotation shaft, and connectable to the first rotation shaft; and

a spiral wing formed around the rotation shaft, wherein at least a portion of the spiral wing formed around the second rotation shaft is flexible,

wherein the outlet portion protrudes from a side wall of the buffer unit, and

the first rotation shaft extends from an inner portion of the buffer unit beyond the side wall.

10. The image forming apparatus of claim 9 , wherein the first rotation shaft includes a rigid core, and

the second rotation shaft and the spiral wing are formed by insert injection molding using the rigid core as an insertion material to be flexible.

11. The image forming apparatus of claim 9 , wherein the spiral wing includes a rigid spiral wing formed around the first rotation shaft and a flexible spiral wing formed around the second rotation shaft,

the first rotation shaft and the rigid spiral wing are integrally formed by plastic injection molding and form a rigid member, and

the second rotation shaft and the flexible spiral wing are formed on the rigid member by double injection molding.

12. The image forming apparatus of claim 9 , wherein the spiral wing includes a rigid spiral wing formed around the first rotation shaft and a flexible spiral wing formed around the second rotation shaft,

the first rotation shaft and the rigid spiral wing are integrally formed by insert injection molding using a metal rigid core as an insertion material and thus form a rigid member, and

the second rotation shaft and the flexible spiral wing are formed on the rigid member by double injection molding.

13. The image forming apparatus of claim 9 , wherein the first rotation shaft includes a rigid core,

the second rotation shaft includes a flexible core that has a smaller bending strength than the rigid core, and

the spiral wing is flexible by being formed around the rigid core and the flexible core by insert injection molding.

14. The image forming apparatus of claim 9 , wherein the spiral wing includes a rigid spiral wing integrally formed around the first rotation shaft, and a flexible spiral wing integrally formed around the second rotation shaft, and

the first rotation shaft and the second rotation shaft are connected to each other via a connector.

15. The image forming apparatus of claim 9 , wherein the spiral wing includes a rigid spiral wing integrally formed around the first rotation shaft, and a flexible spiral wing integrally formed around the second rotation shaft, and

an insertion hole is provided in an end of the first rotation shaft, and an end of the second rotation shaft is inserted into the insertion hole.

16. The image forming apparatus of claim 9 , wherein a bending start location at which the supply pipe starts to bend is spaced apart from an end of the first rotation shaft near the supply pipe by at least about 10 mm.

17. The image forming apparatus of claim 9 , wherein the first rotation shaft extends into the supply pipe beyond the outlet portion.

18. The image forming apparatus of claim 9 , further comprising a driving motor configured to rotate the developer supplier,

wherein a rotation force of the driving motor is transmittable to the first rotation shaft.

19. An image forming apparatus comprising:

a developer cartridge;

a developing device comprising a photoconductor;

a buffer unit between the developer cartridge and the developing device and including:

an inlet portion into which a developer is feedable from the developer cartridge, and

an outlet portion;

a supply pipe configured to connect the outlet portion to the developing device; and

a developer supplier that extends into the supply pipe from the buffer unit, is configured to supply the developer from the buffer unit to the developing device, including:

a rotation shaft, and

a spiral wing,

wherein the outlet portion protrudes from a side wall of the buffer unit, and

the developer supplier includes:

a rigid body extending from an inner portion of the buffer unit beyond the side wall, and

a flexible body extending from the rigid body into the supply pipe and having a smaller bending strength than the rigid body.

20. The image forming apparatus of claim 19 , wherein a bending start location at which the supply pipe starts to bend is spaced apart from an end of the rigid body near the supply pipe by at least about 10 mm.

21. The image forming apparatus of claim 9 , wherein the rigid body extends into the supply pipe beyond the outlet portion.

22. The image forming apparatus of claim 19 , further comprising a driving motor configured to rotate the developer supplier,

wherein a rotation force of the driving motor is transmitted to the rigid body.

23. A supplier for delivering a material through a pipe, the supplier comprising:

a rotation shaft including:

a first rotation shaft that is rigid, and

a second rotation shaft that is flexible, has a smaller bending strength than the first rotation shaft, and is connectable to the first rotation shaft; and

a spiral wing formed around the rotation shaft, wherein at least a portion of the spiral wing formed around the second rotation shaft is flexible.