Patent ID: 7751757

Claim:
A developer cartridge usable with an image forming apparatus, the developer cartridge comprising: a housing having a developer storage chamber; a first stirring unit rotatably mounted in the housing, the first stirring unit having a first rotary shaft; a second stirring unit rotatably mounted in the housing, the second stirring unit having a second rotary shaft; a rotary member coaxially coupled to the second rotary shaft of the second stirring unit to transmit a rotary force to the second stirring unit, the rotary member having an interference portion; a power transmission member coaxially disposed on the second rotary shaft of the second stirring unit such that the power transmission member is rotatably coupled to the rotary member, the power transmission member having a gear portion formed at an outer circumference thereof and a catching portion located such that the interference portion of the rotary member interferes with the catching portion after a rotation of the power transmission member by a predetermined angle; a connection gear disposed to engage with the gear portion of the power transmission member; and a power transmission gear disposed to engage with the connection gear, the power transmission gear being coaxially coupled to the first rotary shaft of the first stirring unit to transmit a rotary force to the first stirring unit, wherein a rotary force of the power transmission member is continuously transmitted to the first stirring unit via the connection gear and the power transmission gear, and the power transmission member transmits the rotary force to the second stirring unit at a point of time when the interference portion of the rotary member interferes with the catching portion of the power transmission member after an idling of the power transmission member relative to the rotary member for a predetermined time.