Developer supply container, developer supplying system and image forming apparatus having filtered venting

A developer supplying system comprising a developer receiving apparatus, and a developer supply container detachably mountable to said developer receiving apparatus, wherein:

• said developer receiving apparatus includes a developer receiving portion for receiving a developer, a filter for permitting venting of air into and out of said developer receiving portion, and a driver for applying a driving force to said developer supply container;
• and
• said developer supply container includes a developer accommodating portion for accommodating the developer having a fluidity energy of not less than 4.3×10−4 kg·m2/s2 and not more than 4.14×10−3 kg·m2/s2;
• a discharge opening for permitting discharge of the developer out of said developer accommodating portion, said discharge opening having an area not more than 12.6 mm2;
• a driving force receiving portion for receiving a driving force from said driver;
• and an air flow generating mechanism for generating repeated and alternating inward and outward air flow through the discharge opening while venting into and out of said developer receiving portion through said filter.

A developer supplying system comprising a developer receiving apparatus, and a developer supply container detachably mountable to said developer receiving apparatus, wherein:

• said developer receiving apparatus includes a developer receiving portion defining a developer receiving opening for receiving a developer, a filter for permitting venting of air into and out of said developer receiving portion without substantially discharging the toner out of said developer receiving portion, and a driver for applying a driving force to said developer supply container;
• and
• said developer supply container includes a developer accommodating portion configured to accommodate the developer, a discharge opening configured to permit discharging of the developer from said developer accommodating portion toward said developer receiving portion, a driving force receiving portion configured to receive a driving force from said driver, and a pump portion capable of being driven by the driving force received by said driving force receiving portion to alternate repeatedly an air discharging operation and an air suction operation through said discharge opening and said filter, with the discharging operation supplying the developer from said developer supply container to said developer receiving portion while discharging the air out of said developer receiving apparatus through said filter and sucking air into said developer receiving apparatus through said filter,
• wherein said discharge opening has an area not more than 12.6 mm2.