An image forming apparatus includes a motor, a first conveyer and a second conveyer to nip and convey a recordable medium, an urging member to urge one of the first and second conveyers toward the other, a cam member driven by a driving force from the motor to change intensities of pressure in a nipping area, a first gear system to transmit the driving force to the first conveyer, a second gear system to transmit the driving force to the cam member, an engaging member being engaged with a cam gear to rotate integrally and being one of a worm gear and a one-way gear, and a swing gear swingable between a first position, in which the swing gear transmits the driving force to the first gear system, and a second position, in which the swing gear transmits the driving force to the second gear system.