Patent ID: 8177219

Claim:
A transmission mechanism, for transmitting power to a transmission shaft of a sheet feeding mechanism, comprising: a transmission gear train for transmitting the power; an output gear for driving the transmission shaft of the sheet feeding mechanism in order to transport a sheet of a document; and a switch element, disposed between the transmission gear train and the output gear, for switching the power transmitted from the transmission gear train to the output gear, the switch element comprising: a movable arm; a driving gear driven by the transmission gear train to rotate in a forward direction or a reverse direction; a switching gear set, attached to the arm and meshing with the driving gear, the switching gear set changing its rotational direction corresponding to a rotational direction of the driving gear; and a clutch device for restricting movement of the arm to enable the switching gear set to be disengaged from the output gear; wherein when the output gear meshes with the switching gear set, the output gear changes its rotational direction according to the rotational direction of the switching gear set and thus changes a rotational direction of the transmission shaft of the sheet feeding mechanism; and when the output gear is disengaged from the switching gear set, the output gear and the transmission shaft of the sheet feeding mechanism are not driven by the power.