Patent ID: 7522851

Claim:
A developing device to which a developer container is detachably attached, said developer container having an outlet opening through which a developer is supplied and an opening-and-closing body that opens and closes said outlet opening, said developing device comprising: a storing portion in which said developer is stored; an agitating member provided in said storing portion for agitating said developer stored in said storing portion; a supply opening through which said developer is supplied from said developer container to said storing portion, said supply opening being provided on an upper part of said storing portion and being located at substantially a center of said storing portion in a longitudinal direction of said storing portion; and an adjusting mechanism for adjusting the supply of said developer to said storing portion through said supply opening, said adjusting mechanism opening said supply opening when an amount of said developer in said storing portion is less than a predetermined amount, said adjusting mechanism closing said supply opening when the amount of said developer in said storing portion is greater than or equal to the predetermined amount, to stop the supply of said developer to said storing portion, so that a predetermined space is formed in said storing portion.