Electrophotographic image forming apparatus, developing apparatus, and coupling member

摘要

A developing device usable with an electrophotographic image forming apparatus, and movable in a direction substantially perpendicular to an axial direction of a driving shaft comprising a coupling member for transmitting a rotating force to the developing roller, capable of taking a rotational force transmitting angular position for transmitting the rotational force, a pre-engagement angular position which is taken before the coupling member is engaged with the rotating force applying portion and in which the coupling member is inclined away from the rotational force transmitting angular position, and a disengaging angular position which is taken for the coupling member to disengage from the driving shaft and in which the coupling member i inclined away from the rotational force transmitting angular position in a direction opposite to the pre-engagement angular position; wherein in response to a movement of the developing device, the coupling member moves from the pre-engagement angular position to the rotational force transmitting angular position to be opposed to the driving shaft, and wherein when the movable member makes a further movement in the same direction, the coupling member is disengaged from the driving shaft by moving from the rotational force transmitting angular position to the disengaging angular position.