Multi-link hinge

1. A multi-link hinge for facilitating opening and closing of a door with respect to a main body of an apparatus, the multi-link hinge comprising:

a cam rotatably coupled to the main body of the apparatus with a cam pivot shaft affixed to the main body;

an arm link rotatably coupled to the door;

an outer link having a first side portion rotatably coupled to the cam and a second side portion rotatably coupled to the arm link;

an inner link disposed at a lower portion of the outer link and having a first side portion rotatably coupled to the main body and a second side portion rotatably coupled to the arm link;

a connection link having a first side portion rotatably coupled to the cam and a second side portion rotatably coupled to the inner link to transmit a force rotating the inner link in a direction opposite to a rotating direction of the cam; and

an elastic member provided at a lower portion of the cam, and having a first side portion rotatably coupled to the main body with an elastic member pivot shaft affixed to the main body and a second side portion rotatably coupled to the cam with an elastic member connection shaft affixed to cam, wherein the elastic member is configured to provide an elastic pushing force between the elastic member pivot shaft and the elastic member connection shaft and toward the cam so as to bias the cam clockwise in response to a door opening motion and to bias the cam counterclockwise in response to a door closing motion,

wherein, in a closed state of the door, a force transmitting direction of the elastic pushing force of the elastic member is in a slight right direction from a straight line between a center the elastic member pivot shaft and a center of the elastic member connection shaft to facilitate maintaining the door to be in closed state, and the force transmitting direction of the elastic pushing force is gradually moved to a leftward direction as the door is progressively opened by the door opening motion by operation of the cam and the elastic member, and vice versa, as the door is progressively closed by the door closing motion.

2. The multi-link hinge of claim 1 , further comprising:

a tray driving part configured to operate a tray to slide into and out of the main body in conjunction with the door motions,

wherein a cam profile is formed on an outer circumferential surface of the cam,

wherein the cam profile includes a try driving cam profile, which is defined at the cam profile between a portion of the cam coupled to the outer link and a portion of the cam coupled to the elastic member, the tray driving cam profile including a concave portion and a convex portion.

3. The multi-link hinge of claim 2 , wherein the tray driving part comprises:

a connector having a first side portion rotatably coupled to the main body and a second side portion coupled to the tray;

a cam link having a first side portion coupled to the connector and a second side portion connected to the cam to be rollably moved along the tray driving cam profile; and

a tray spring having a first side portion coupled to the connector and a second side portion coupled to the main body, and configured to provide a force pulling the connector toward the cam.

4. The multi-link hinge of claim 3 , wherein the convex portion of the tray driving cam profile includes a recessed portion, and the second side portion of the cam link in a rollably moved state is seated on the recessed portion to detect that the door is in a full open state.

5. The multi-link hinge of claim 2 , further comprising: a damper provided at one side of the elastic member, wherein the damper is configured to be brought into contact with the convex portion of the tray driving cam profile when the cam is rotated counterclockwise due to the door closing motion so that the damper prevents the door from being suddenly closed.

6. The multi-link hinge of claim 1 , wherein the elastic member comprises a main spring, a spring guide inserted in the main spring, and a spring cover coupled to the spring guide.