Power transmission method and apparatus, medium discharging apparatus using the same, and image forming device having the medium discharging apparatus

A medium discharging apparatus of an image forming device comprising:

• a medium discharging frame;
• a driving roller assembly rotatably disposed to the discharging frame, and having a driving axis, and a plurality of driving rollers disposed on the driving axis;
• a driven roller assembly rotatably disposed to the discharging frame to be spaced apart from the driving roller assembly, and having a driven axis, and a plurality of driven rollers disposed on the driven axis;
• and
• a friction roller disposed above a line connecting between centers of the driving roller assembly and the driven roller assembly to transmit a driving force from the driving roller assembly to the driven roller assembly.

A medium discharging apparatus of an image forming device comprising:

• a medium discharging frame;
• a driving roller assembly disposed to the discharging frame to be rotatable in forward and backward directions, and having a driving axis, and a plurality of driving rollers disposed on the driving axis;
• a driven roller assembly rotatably disposed to the discharging frame to be spaced apart from the driving roller assembly, and having a driven axis, and a plurality of driven rollers disposed on the driven axis;
• and
• a friction roller placed on the driving roller assembly and the driven roller assembly to rotate according to a rotation of the driving roller assembly,
• wherein in a forward rotation of the driving roller assembly, the friction roller rotates in a state of being interposed between the driving rollers and the driven rollers to transmit a driving force, and in a backward rotation of the driving roller assembly rises up from the driving rollers and the driven rollers to block the driving force from being transmitted to the driven rollers.

An image forming device comprising:

• a medium supplying unit;
• an image forming unit to form a toner image on a printing medium supplied from the medium supplying unit;
• a fixing unit to fix the toner image on the printing medium;
• and
• a medium discharging apparatus to discharge the printing medium on which the toner image is fixed, the medium discharging apparatus comprising:
• a medium discharging frame,
• a driving roller assembly rotatably disposed at the discharging frame, and having a driving axis, and a plurality of driving rollers disposed on the driving axis,
• a driven roller assembly rotatably disposed to the discharging frame to be spaced apart from the driving roller assembly, and having a driven axis, and a plurality of driven rollers disposed on the driven axis, and
• a friction roller disposed above a line connecting centers of the driving roller assembly and the driven roller assembly to transmit a driving force from the driving roller assembly to the driven roller assembly.

An image forming device comprising:

• a medium supplying unit;
• an image forming unit to form a toner image on a printing medium supplied from the medium supplying unit;
• a fixing unit to fix the toner image on the printing medium;
• and
• a medium discharging apparatus to discharge the printing medium on which the toner image is fixed, the medium discharging apparatus comprising:
• a medium discharging frame,
• a driving roller assembly disposed to the discharging frame to be rotatable in forward and backward directions, and having a driving axis, and a plurality of driving rollers disposed on the driving axis,
• a driven roller assembly rotatably disposed to the discharging frame to be spaced apart from the driving roller assembly, and having a driven axis, and a plurality of driven rollers disposed on the driven axis, and
• a friction roller placed on the driving roller assembly and the driven roller assembly to rotate according to a rotation of the driving roller assembly,
• wherein in a forward rotation of the driving roller assembly, the friction roller rotates in a state of being interposed between the driving rollers and the driven rollers to transmit a driving force, and in a backward rotation of the driving roller assembly floats up from the driving rollers and the driven rollers to block the driving force from being transmitted to the driven rollers.

A power transmission apparatus, comprising:

• a driving roller;
• a driven roller spaced apart from the driving roller;
• and
• a friction roller having a center disposed above a line connecting centers of the driving roller and the driven roller to transmit a driving force from the driving roller to the driven roller when the driving roller rotates in a predetermined direction only.

An image forming device, comprising:

• a medium supplying unit;
• an image forming unit to form a toner image on a printing medium supplied from the medium supplying unit;
• a fixing unit to fix the toner image on the printing medium;
• and
• a medium discharging apparatus to discharge the printing medium on which the toner image is fixed, the medium discharging apparatus comprising:
• a medium discharging frame,
• a driving roller assembly rotatably disposed at the discharging frame, and having a driving axis, and a plurality of driving rollers disposed on the driving axis,
• a driven roller assembly rotatably disposed at the discharging frame to be spaced apart from the driving roller assembly, and having a driven axis, and a plurality of driven rollers disposed on the driven axis, and
• a friction roller having a center disposed above a line connecting centers of the driving roller assembly and the driven roller assembly to transmit a driving force from the driving roller assembly to the driven roller assembly when the driving rollers are rotated in a predetermined direction.