Cartridge detachably mountable to main assembly of electrophotographic image forming apparatus, assembling method for drive transmitting device for photosensitive drum, and electrophotographic image forming apparatus

1. A coupling member for an image forming apparatus cartridge, the coupling member being configured to rotate about a rotational axis thereof, the coupling member comprising:

a first end portion including an outer surface and a plurality of surfaces forming a recess extending in a direction from the outer surface toward the rotational axis, the plurality of surfaces including a first surface, a second surface opposite to the first surface, and a third surface extending between the first surface and the second surface, wherein, as viewed in a direction toward the recess and perpendicular to the rotational axis, the third surface faces toward outside of the recess, and wherein both of the first and second surfaces are sloped with respect to a plane that is perpendicular to the rotational axis such that a distance measured along a direction of the rotational axis between the first and second surfaces decreases as a distance along the first and second surfaces from the outer surface increases; and

a second end portion opposite to the first end portion, the second end portion including at least one projection configured to receive a rotational force.

2. A coupling member according to claim 1 , further comprising a connecting portion that connects the first end portion and the second end portion.

3. A coupling member according to claim 1 , wherein, as measured along a line perpendicular to the rotational axis of the coupling member, a distance from the rotational axis to an outermost surface of the connecting portion is less than a distance from the rotational axis to at least part of an outermost surface of the second end portion.

4. A coupling member according to claim 1 , wherein the second end portion includes two projections that are positioned on opposite sides of the second end portion.

5. A coupling member according to claim 4 , wherein the second end portion includes a surface with a recess formed therein, with the two projections projecting from the surface.

6. A coupling member according to claim 1 , wherein the outer surface has a substantially spherical shape.

7. A coupling member for an image forming apparatus cartridge, the coupling member being configured to rotate about a rotational axis thereof, the coupling member comprising:

a first end portion including an outer surface, the first end portion including:

(i) a first plurality of surfaces forming a first recess, the first plurality of surfaces including (i-i) a first surface, (i-ii) a second surface opposite to the first surface, and (i-iii) a third surface extending between the first surface and the second surface, wherein, as viewed in a direction toward the recess and perpendicular to the rotational axis, the third surface faces toward outside of the recess, and wherein both of the first and second surfaces are sloped with respect to a plane that is perpendicular to the rotational axis such that a distance measured along a direction of the rotational axis between the surfaces decreases as a distance along the surfaces from the outer surface increases, and

(ii) a second plurality of surfaces forming a second recess, the second plurality of surfaces including (ii-i) a first surface, (ii-ii) a second surface opposite to the first surface, and (ii-iii) a third surface extending between the first surface and the second surface, wherein, as viewed in a direction toward the second recess and perpendicular to the rotational axis, the third surface faces toward outside of the second recess, and wherein both of the first and second surfaces are sloped with respect to a plane that is perpendicular to the rotational axis such that a distance measured along a direction of the rotational axis between the first and second surfaces decreases as a distance along the first and second surfaces from the outer surface increases; and

a second end portion opposite to the first end portion, the second end portion including at least one projection configured to receive a rotational force,

wherein, as viewed in a direction toward the first and second recesses and perpendicular to the rotational axis, and the first recess and second recess are open to opposite sides of the first end portion.

8. A coupling member according to claim 7 , further comprising a connecting portion that connects the first end portion and the second end portion.

9. A coupling member according to claim 7 , wherein, as measured along a line perpendicular to the rotational axis of the coupling member, a distance from the rotational axis to an outermost surface of the connecting portion is less than a distance from the rotational axis to at least part of an outermost surface of the second end portion.

10. A coupling member according to claim 7 , wherein the second end portion includes two projections that are positioned on opposite sides of the second end portion.

11. A coupling member according to claim 10 , wherein the second end portion includes a surface with a recess formed therein, with the two projections projecting from the surface.

12. A coupling member according to claim 7 , wherein the outer surface has a substantially spherical shape.