Electrophotographic image forming apparatus, developing apparatus, and coupling member

1. An image forming apparatus cartridge comprising:

a casing;

a developer roller having an axis L 1 , the developer roller being rotatably supported in the casing to permit rotation about the axis L 1 ;

a coupling member having an axis L 2 , the coupling member having (i) a first end portion operatively connected to the developer roller, (ii) a second end portion, and (iii) a connecting portion connecting the first end portion and the second end portion; and

an urging member that biases the coupling member,

wherein the coupling member is movable between a first position in which the axis L 2 of the coupling member is substantially parallel to and offset from the axis L 1 of the developer roller, and a second position in which the axis L 2 of the coupling member is fully inclined with respect to the axis L 1 of the developing roller,

wherein the urging member biases the coupling member to the second position, and

wherein, when the coupling member is in the second position, a maximum angle of inclination of the axis L 2 with respect to the axis L 1 is about 20 degrees to about 60 degrees.

2. An image forming apparatus cartridge according to claim 1 , wherein the coupling member is movable to a third position in which the axis L 2 is inclined with respect to the axis L 1 in a direction different from the direction in which the coupling member is inclined when in the second position.

3. An image forming apparatus cartridge according to claim 2 , wherein, when the coupling member is in the third position, the axis L 2 is inclined with respect to the axis L 1 in a direction opposite to the direction in which the coupling member is inclined when in the second position.

4. An image forming apparatus cartridge according to claim 2 , wherein, when the coupling member is in the third position, a portion of the axis L 2 at the first end portion side of the coupling member is closer to the axis L 1 than a portion of the axis L 2 at the second end portion side of the coupling member.

5. An image forming apparatus cartridge according to claim 1 , wherein the casing comprises a guide portion capable of guiding the coupling member toward the second position.

6. An image forming apparatus cartridge according to claim 5 , further comprising a contact portion capable of contacting the coupling member to position the coupling member at the second position.

7. An image forming apparatus cartridge according to claim 6 , wherein the casing provides the contact portion.

8. An image forming apparatus cartridge according to claim 4 , wherein, when the coupling member is in the third position, the axis L 2 is inclined from about 20 degrees to about 60 degrees with respect to the axis L 1 .

9. An image forming apparatus cartridge according claim 1 , wherein the second end portion comprises a surface that is substantially perpendicular to the axis L 2 , with two projections extending from the surface at diametrically opposed positions.

10. An image forming apparatus cartridge according to claim 9 , wherein the surface includes an opening to a recess, with the recess including a surface facing away from the first end portion.

11. An image forming apparatus cartridge according to claim 9 , wherein each projection includes a surface at least a portion of which overhangs a portion of the second end portion.

12. An image forming apparatus cartridge according to claim 1 , further comprising:

a first gear connected to the developer roller; and

a second gear connected to the coupling member, the second gear being in meshing engagement with the first gear.

13. An image forming apparatus cartridge according to claim 12 , wherein the second gear is connected to the coupling member such that the coupling member can partially rotate about the axis L 2 without transmitting a force to the second gear.

14. An image forming apparatus cartridge according to claim 13 , wherein the second gear has a hollow portion, and at least part of the first end portion of the coupling member is positioned within the hollow portion of the second gear.

15. An image forming apparatus cartridge according to claim 14 , wherein at least the part of the first end portion of the coupling member is supported by the hollow portion.

16. An image forming apparatus cartridge according to claim 15 , wherein the first end portion of the coupling member comprises a part of a spherical shape.

17. An image forming apparatus cartridge according to claim 16 , wherein the connecting portion includes a shaft substantially along the axis L 2 .

18. An image forming apparatus cartridge according to claim 1 , wherein the urging member is a torsion spring that contacts the connecting portion of the coupling member.

19. An image forming apparatus cartridge according to claim 1 , wherein the coupling member can be inclined in substantially any direction relative to the first position.

20. An image forming apparatus cartridge according to claim 1 , wherein the coupling member is made from a resin material.

21. An image forming apparatus cartridge according to claim 20 , wherein the resin material is polyacetal.

22. An image forming apparatus cartridge according to claim 1 , wherein the coupling member is made from a metallic material.

23. An image forming apparatus cartridge according to claim 1 , wherein at least the second end portion of the coupling member is outside of the casing.