Developing device having movable coupling member for engagement to electrophotographic image forming apparatus

An electrophotographic image forming apparatus for forming an image on a recording material, said electrophotographic image forming apparatus comprising:

• i) a driving shaft rotatable by a motor and having a rotating force applying portion, wherein said driving shaft is not movable in a direction perpendicular to an axis thereof;
• ii) a movable member;
• iii) a developing device which is movable in a direction substantially perpendicular to an axial direction of said driving shaft in response to movement of said movable member in a state that said developing device is mounted to said movable member, in response to the moment of said movable member, said developing device including:
• a frame,
• a developing roller, provided in said frame, for developing an electrostatic latent image formed on an electrophotographic photosensitive drum, said developing roller being rotatable about an axis, wherein said developing roller is contacted to and separated from said electrophotographic photosensitive member drum in response to movement of said movable member, and
• a coupling member for transmitting a rotating force to said developing roller, said coupling member including a rotating force receiving portion engageable with said rotating force applying portion to receive a rotating force from said driving shaft, and a rotating force transmitting portion for transmitting the rotating force received through said rotating force receiving portion to said developing roller,
• iv) a cylindrical member movably supporting one end portion of said coupling member inside of the cylindrical member so that said coupling member is capable of taking (a) a rotational force transmitting angular position for transmitting the rotational force for rotating said developing roller to said developing roller, (b) a pre-engagement angular position which is taken before said coupling member is engaged with said rotating force applying portion and in which said coupling member is inclined away from the rotational force transmitting angular position, and (c) a disengaging angular position which is taken for said coupling member to disengage from said driving shaft and in which said coupling member is inclined away from the rotational force transmitting angular position in a direction opposite to the pre-engagement angular position to disengage from said driving shaft said cylindrical member being configured to transmit the rotational force from said coupling member to said developing roller,
• wherein said frame includes (i) a supporting portion configured to support said cylindrical member rotatably and (ii) a regulating portion capable of regulating said coupling member at the pre-engagement angular position,
• wherein said supporting portion encompasses said regulating portion as seen along a rotational axis of cylindrical member;
• and
• wherein in response to a movement of said developing device when said movable member moves in the one direction, said coupling member moves from the pre-engagement angular position to the rotational force transmitting angular position, and wherein when said movable member makes a further movement in said the direction, in response to the further movement, said coupling member is moved from the rotational force transmitting angular position to the disengaging angular position to disengage said coupling member from said driving shaft, and
• wherein, when said coupling member moves from the pre-engagement angular position to the rotational force transmitting angular position in response to the movement of said developing device, said developing roller is contacted to said electrophotographic photosensitive member in a state that said developing roller is rotated through engagement between said coupling member and said rotating force applying portion.