US Patent 7738818 Developer supply container

In order to stabilize opening/closing operations of an apparatus shutter of a toner receiving apparatus utilizing rotation of a toner supply container, the toner supply container is provided, at a peripheral surface thereof, with a snap lock portion, which is engaged with the apparatus shutter to effect opening/closing operations of the apparatus shutter by rotation of the toner supply container. A release force F(N) required for releasing snap lock engagement of the snap lock portion with the apparatus shutter and an elastic repulsive force P(N) of the snap lock portion are set to satisfy the following relationship:P=kF where 0.25≦k≦1.