Door opening and closing unit to control door rotating speed and image forming apparatus having the same

1. A door opening and closing unit for an image forming apparatus, the image forming apparatus comprising a main body, and a door rotatably mounted on the main body, the door opening and closing unit comprising:

a door speed control unit coupling the door to the main body, the door speed control unit comprising:

a coupling boss;

a guide groove that engages the coupling boss and along which the coupling boss moves as the door rotates relative to the main body; and

a speed control groove provided on one side of the guide groove inclined at a predetermined angle with respect to a lengthwise direction of the guide groove,

wherein the door speed control unit controls a frictional force between the coupling boss and the guide groove according to a rotating angle of the door relative to the main body to control a rotating speed of the door as the door rotates relative to the main body,

wherein the door speed control unit gradually reduces a rotating speed of the door as the door rotates from a closed position in which the door is rotated against the main body to a fully open position in which the door is maximally rotated away from the main body.

2. The door opening and closing unit of claim 1 , wherein the guide groove comprises:

a starting point at which the coupling boss is positioned when the door is in the closed position; and

an ending point at which the coupling boss is positioned when the door is in the fully open position; and

wherein a width of the guide groove at the starting point is greater than a width of the coupling boss.

3. The door opening and closing unit of claim 2 , wherein the width of the guide groove decreases from the starting point to the ending point according to a distance along the guide groove from the starting point.

4. The door opening and closing unit of claim 2 , wherein the width of the guide groove at the ending point is less than the width of the coupling boss.

5. The door opening and closing unit of claim 2 , wherein the door speed control unit further comprises a frictional member disposed so that the coupling boss is in contact with the frictional member as the coupling boss moves along the guide groove as the door rotates relative to the main body; and

wherein a thickness of the frictional member increases from the starting point of the guide groove to the ending point of the guide groove according to a distance along the guide groove from the starting point.

6. The door closing and opening unit of claim 5 , wherein the frictional member is disposed on edges of the guide groove so that the coupling boss contacts the frictional member as the coupling boss moves along the guide groove as the door rotates relative to the main body; and

wherein the thickness of the frictional member increases in a width direction of the guide groove from the starting point of the guide groove to the ending point of the guide groove according to a distance along the guide groove from the starting point.

7. The door opening and closing unit of claim 5 , wherein the frictional member is one of a sponge member, a brush member, a fiber member, and a rubber member.

8. The door opening and closing unit of claim 1 , wherein the guide groove comprises:

a starting point at which the coupling boss is positioned when the door is in the closed position; and

an ending point at which the coupling boss is positioned when the door is in the fully open position; and

wherein the predetermined angle is an angle that causes a distance between the guide groove and the speed control groove to increase from the starting point to the ending point according to a distance along the guide groove from the starting point.

9. The door opening and closing unit of claim 1 , further comprising a link member rotatably mounted on the main body or the door;

wherein if the link member is rotatably mounted on the main body, the door speed control unit couples the link member to the door; and

wherein if the link member is rotatably mounted on the door, the door speed control unit couples the link member to the main body.

10. A door opening and closing unit for an image forming apparatus, the image forming apparatus comprising a main body, and a door rotatably mounted on the main body, the door opening and closing unit comprising:

a door speed control unit coupling the door to the main body, the door speed control unit comprising:

a coupling boss

a guide groove that engages the coupling boss and along which the coupling boss moves as the door rotates relative to the main body, the guide groove comprising a starting point at which the coupling boss is positioned when the door is in the closed position, and an ending point at which the coupling boss is positioned when the door is in the fully open position; and

a speed control groove provided on one side of the guide groove so that the speed control groove is farthest from the guide groove at the starting point of the guide groove, and is closest to the guide groove at the ending point of the guide groove,

wherein the guide groove is a straight groove or a curved groove; and

wherein the speed control groove is a straight groove or a curved groove,

wherein the door speed control unit controls a frictional force between the coupling boss and the guide groove according to a rotating angle of the door relative to the main body to control a rotating speed of the door as the door rotates relative to the main body,

wherein the door speed control unit gradually reduces a rotating speed of the door as the door rotates from a closed position in which the door is rotated against the main body to a fully open position in which the door is maximally rotated away from the main body.

11. A door opening and closing unit for an image forming apparatus, the image forming apparatus comprising a main body, and a door rotatably mounted on the main body, the door opening and closing unit comprising:

a door speed control unit coupling the door to the main body, the door speed control unit comprising:

a coupling boss;

a guide groove that engages the coupling boss and along which the coupling boss moves as the door rotates relative to the main body;

a first speed control groove provided on a first side of the guide groove inclined at a first predetermined angle with respect to a lengthwise direction of the guide groove; and

a second speed control groove provided on a second side of the guide groove inclined at a second predetermined angle with respect to the lengthwise direction of the guide groove,

wherein the door speed control unit controls a frictional force between the coupling boss and the guide groove according to a rotating angle of the door relative to the main body to control a rotating speed of the door as the door rotates relative to the main body, and

wherein the door speed control unit gradually reduces a rotating speed of the door as the door rotates from a closed position in which the door is rotated against the main body to a fully open position in which the door is maximally rotated away from the main body.

12. The door opening and closing unit of claim 11 , wherein the second predetermined angle is different from the first predetermined angle.

13. The door opening and closing unit of claim 11 , wherein the guide groove comprises:

a starting point at which the coupling boss is positioned when the door is in the closed position; and

an ending point at which the coupling boss is positioned when the door is in a fully open position in which the door is rotated as far away from the main body as it will go;

wherein the first predetermined angle is an angle that causes a distance between the guide groove and the first speed control groove to increase from the starting point to the ending point according to a distance along the guide groove from the starting point; and

wherein the second predetermined angle is an angle that causes a distance between the guide groove and the second speed control groove to increase from the starting point to the ending point according to a distance along the guide groove from the starting point.

14. The door opening and closing unit of claim 13 , wherein the distance between the guide groove and the second speed control groove is different from the distance between the guide groove and the first speed control groove at least one point along the guide groove.

15. A door speed control unit for use in an image forming unit having a door rotatably attached to a housing a hinge to enable the door to open and close by rotating relative to the housing, the door speed control unit comprising:

a boss connectable to the door or the housing; and

a surface comprising a groove into which the boss is slideably inserted to slide in an opening direction as the door opens and at least one additional groove defining an area between the additional groove and the groove, the area having an increasing area as a function of distance in the opening direction that increases an amount of friction applied to the boss as the boss slides in the opening direction;

wherein the surface comprising the groove is shaped to increasingly interfere with a sliding movement of the boss in the opening direction in proportion to a distance traveled by the boss in the opening direction so as to decrease a rotational rate at which the door rotates relative to the housing as the door opens.

16. The door speed control unit of claim 15 , wherein the groove is curved about a first radius to generally correspond to a direction of rotation of the door relative to the housing; and

wherein the at least one additional groove is curved about a second radius other than the first radius so as to define the area.

17. The door speed control unit of claim 15 , wherein the groove is curved to generally correspond to a direction of rotation of the door relative to the housing.

18. The door speed control unit of claim 15 , wherein the groove has a decreasing width as a function of distance in the opening direction that increases an amount of friction applied to the boss as the boss slides in the opening direction.