A driving mechanism includes: a first contacting member that comes into contact with a contacted member; a supporting member that supports the first contacting member and is reciprocatably provided, the supporting member moving the first contacting member into contact with or retracts from the contacted member; a cam that reciprocates the supporting member; and a driving force transmission member that is provided to transmit a driving force to the cam, the driving force transmission member is engaged with the cam by transmit a first driving force, and is disengaged from the cam by a second driving force. In the driving mechanism, the second driving force is applied to the driving force transmission member after the cam is stopped in a state where the cam comes into contact with the supporting member on a small radius end of the cam.