An image forming apparatus includes a transporter for transporting a transfer medium to a plurality of image forming stations for transferring images in sequence onto the transfer medium. Each of the plurality of image forming stations has a recording medium onto which a transferred image is formed, an image forming device for forming the image on the recording medium, and a detector for detecting a state of the image formed on the recording medium. A controller operates in first and second modes, wherein the first mode operating conditions of the image forming device are determined based on a detected state of the image formed on the recording medium, and wherein in the second mode, the image forming device is controlled based on the operating conditions determined in the first mode. The controller operates each image forming device in the plurality of image forming stations simultaneously during first mode, and operates the image forming devices in sequence, at predetermined time intervals, during the second mode.