A drive-force transmitting mechanism includes a drive disk and a driven disk that are rotatable about an axis. The driven disk has two diametrically opposing engagement portions. The drive disk has two levers pivotally mounted thereon, each lever having a clutch pin formed thereon. The two disks are disposed so that the levers are sandwiched between the two disks. The levers are operatively coupled through a coupling member such that rotation of one lever is transmitted to the other. A cam member has a groove that guides a pin member of one lever such that when the drive disk rotates through a first angle, the pins move toward the axis to engage the engagement portions to transmit rotation of the drive disk to the driven disk, and when the drive disk rotates through another angle, the pins move away from the axis to disengage from the engagement portions.