Patent ID: 7283769

Claim:
A driving apparatus of a detachable developing apparatus to transfer driving power of a driving element of the developing apparatus to a developing element, comprising: a shaft; a coupling member comprising: a coupling drive which is connected to the driving element and to which the driving power is transferred from the driving element, a coupling gear to which the driving power is transferred from the coupling drive, and a coupling disc positioned between the coupling drive and the coupling gear to flexibly connect the coupling drive and the coupling gear to each other, and correcting an eccentricity of the shaft between the driving element and the coupling gear; and a power transferring portion including a plurality of gears so as to transfer the driving power from the coupling member to the developing element, wherein at least one of the plurality of gears is a reduction gear to reduce a load applied to the coupling member from the developing element, and a speed reduction ratio between the developing element and the coupling member is greater than 1:1, a rotation speed of the coupling member is higher than a rotation speed of the developing element, and a torsional moment applied to the coupling member is smaller than a torsional moment applied to the developing element.