Developer supply container and developer supplying system

1. A developer supply container comprising:

a developer container body configured to accommodate developer;

a gear portion configured and positioned to receive a force for rotating the developer container body;

a pump portion configured and positioned to act upon the developer container body to discharge the developer out of the developer supply container, the pump portion having a volume that changes with reciprocation of the pump portion; and

a weight configured and positioned to reciprocate the pump portion with a rotation of the developer container body by the force received by the gear.

2. A developer supply container according to claim 1 , wherein the pump portion is connected with the developer container body, and the weight is provided on the pump portion.

3. A developer supply container according to claim 2 , wherein the pump portion includes a flexible bellow-like pump.

4. A developer supply container according to claim 3 , wherein the weight acts upon the pump portion such that a suction action and a delivery action are alternately carried out with the rotation of the developer container body.

5. A developer supply container according to claim 2 , further comprising a developer discharging chamber provided with an opening configured to permit discharging of the developer accommodated in the developer container body, the developer discharging chamber being in fluid communication with a longitudinal end of the developer container body.

6. A developer supply container according to claim 1 , wherein the developer in the developer container body has a fluidity energy of not less than 4.3×10 −4 kg·m 2 /s 2 and not more than 4.14×10 −3 kg·m 2 /s 2 , and

wherein the opening has an area of not more than 12.6 mm 2 .