An image forming apparatus includes an engine unit performing an image forming job; an engine controller to perform the image forming job; and a main controller controlling an operation of the engine unit by communicating with the engine controller in a normal mode and being inactivated if the image forming apparatus changes the mode to a low-power mode. The engine controller performs the image forming job by driving the engine unit in the normal mode under the control of the main controller, and provides a service that corresponds to the low-power mode if the image forming apparatus changes the mode to the low-power mode.