Power transmission device and image forming apparatus having the same

1. A power transmission device of an image forming apparatus, which intermittently transmits power to a driven component from a driving source, comprising:

a shaft;

a first intermittent gear to receive power from the driving source and to rotate on the shaft;

a second intermittent gear arranged so as to move between a first position in which the second intermittent gear is directly connected to the first intermittent gear along an axial direction of the shaft and a second position in which the second intermittent gear is disconnected from the first intermittent gear;

a sliding unit arranged so as to slide along the shaft and to move the second intermittent gear in the axial direction of the shaft; and

a driving unit arranged perpendiculary to the axial direction of the shaft to drive the sliding unit,

wherein the sliding unit includes a hollow sliding body through which the shaft is inserted and a power transforming part incorporated into the hollow sliding body to transform a rotational motion of the driving unit into a linear motion, and

wherein the second intermittent gear is rotatably disposed on an outer peripheral surface of the hollow sliding body to move together with the sliding unit.

2. The power transmission device according to claim 1 , wherein the driving unit includes a motor that rotates in a forward direction and a reverse direction.

3. The power transmission device according to claim 1 , wherein the power transforming part includes a rack gear.

4. The power transmission device according to claim 1 , wherein the second intermittent gear is rotatably mounted to the sliding unit.

5. The power transmission device according to claim 1 , wherein:

the first intermittent gear comprises a first coupling part arranged along the axial direction of the shaft; and

the second intermittent gear comprises a second coupling part arranged along the axial direction of the shaft opposite the first coupling part so as to engage the second intermittent gear with the first intermittent gear.

6. A power transmission device of an image forming apparatus to intermittently transmits power to a driven component from a driving source, comprising:

a shaft;

a first intermittent gear to receive power from the driving source and arranged so as to rotate on the shaft;

a sliding unit slidably mounted to the shaft, the sliding unit including a hollow sliding body through which the shaft is inserted and a rack gear incorporated into the hollow sliding body;

a second intermittent gear rotatably mounted to an outer peripheral surface of the hollow sliding body of the sliding unit so as to transmit power to the driven component while moving together with the sliding unit; and

a motor arranged perpendicularly to an axial direction of the shaft to move the sliding unit between a first position in which the second intermittent gear is directly connected to the first intermittent gear and a second position in which the second intermittent gear is disconnected from the first intermittent gear.

7. The power transmission device according to claim 6 , wherein

a rack gear provided on the a hollow sliding body as part of the power transforming part.

8. The power transmission device according to claim 6 , wherein:

the first intermittent gear comprises a first coupling part arranged along the axial direction of the shaft; and

the second intermittent gear comprises a second coupling part arranged along the axial direction of the shaft opposite the first coupling part so as to engage the second intermittent gear with the first intermittent gear.

9. An image forming apparatus including a driving source, a power transmission gear to receive power from the driving source and arranged so as to rotate, and a power transmission device to intermittently transmit power to a driven component from the driving source, the power transmission device comprising:

a shaft;

a first intermittent gear engaged with the power transmission gear so as to rotate on the shaft;

a second intermittent gear arranged so as to rotate on the shaft to receive power from the first intermittent gear, and to transmit power to the driven component;

a sliding unit arranged so as to slide along the shaft in an axial direction of the shaft and to move the second intermittent gear between a first position in which the second intermittent gear is directly connected to the first intermittent gear and a second position in which the second intermittent gear is disconnected from the first intermittent gear; and

a driving unit arranged perpendicularly to the axial direction of the shaft to drive the sliding unit,

wherein the sliding unit includes a hollow sliding body through which the shaft is inserted and a power transforming part incorporated into the hollow sliding body to transform a rotational motion of the driving unit into a linear motion, and

wherein the second intermittent gear is rotatably disposed on an outer peripheral surface of the hollow sliding body to move together with the sliding unit.

10. The image forming apparatus according to claim 9 , wherein the driving unit includes a motor to rotate in a forward direction and a reverse direction.

11. The image forming apparatus according to claim 9 , wherein the power transforming part includes a rack gear.

12. The image forming apparatus according to claim 11 , wherein the driving unit comprises a pinion to engage with the rack gear.

13. The image forming apparatus according to claim 9 , wherein:

the sliding unit includes a cylindrical sliding body through which the shaft is inserted, and

the second intermittent gear is rotatably mounted to the cylindrical sliding body