Patent ID: 8862031

Claim:
An image forming apparatus comprising: a rotation driving source; a black developing unit comprising a black developing roller configured to carry a black developing agent; a color developing unit comprising a color developing roller configured to carry a color developing agent; a first gear configured to drive the black developing roller to rotate; a second gear configured to drive the color developing roller to rotate; a development drive transmission mechanism configured to transmit rotation driving force of a predetermined direction from the rotation driving source to the first gear and to the second gear; and a switching mechanism configured to switch modes between a first mode in which the rotation driving force is transmitted to the first gear and to the second gear, a second mode in which the rotation driving force is transmitted to the first gear but not transmitted to the second gear, and a third mode in which the rotation driving force is not transmitted to either the first gear or the second gear, wherein: the development drive transmission mechanism comprises: a first intermediate gear capable of engaging with and disengaging from the first gear, the rotation driving force being transmitted to the first intermediate gear, and a second intermediate gear capable of engaging with and disengaging from the second gear, the rotation driving force being transmitted via the first intermediate gear; and the switching mechanism comprises a linear cam member configured to move linearly and to move the first intermediate gear and the second intermediate gear such that: in the first mode, the first gear engages the first intermediate gear and the second gear engages the second intermediate gear; in the second mode, the first gear engages the first and second intermediate gears and the second gear is disengaged from the second intermediate gear; and in the third mode, the first gear is disengaged from the first intermediate gear.