Drive transmission device and image forming apparatus including the same

A drive transmission device including a driving rotational body, a driven rotational body that rotates by engaging with the driving rotational body, a driven member that is driven by the rotation of the driven rotational body, and an elastic member that rotates the driven rotational body by an elastic force when the driven rotational body does not engage with the driving rotational body, the drive transmission device comprising:

• a first rotational body and a second rotational body arranged downstream of the driven rotational body in a drive train that transmits a driving force from the driving rotational body to the driven member, the first rotational body being configured to rotate in synchronization with the driven rotational body, the second rotational body being configured to be rotated by the first rotational body and drive the driven member,
• wherein, when the driven rotational body rotates by the elastic force of the elastic member, a case in which the first rotational body rotates without rotating the second rotational body, and a case in which the first rotational body rotates while rotating the second rotational body are provided,
• wherein the driven member can move to a first position and a second position as a result that the driven member is driven by the second rotational body and moves, and a load required for the driven member to move is larger when the driven member is displaced to the first position than a load required when the driven member is displaced to the second position, and
• wherein the first rotational body rotates without rotating the second rotational body by the elastic force of the elastic member when the driven member is at the first position, and the first rotational body rotates while rotating the second rotational body by the elastic force of the elastic member when the driven member is at the second position.