1. An image forming apparatus, comprising: an image forming unit; and a surface reflection detector to detect reflection characteristics of a surface of a recording medium, the image forming unit including an image forming station to form a detection sample image and a toner image on the recording medium; a controller to set a detection sample image output mode to output the detection sample image; and a fixing device to fix the detection sample image and the toner image on the recording medium, the surface reflection detector connected to the controller and including a projector to project parallel light against a target; and an angular distribution detector to detect an angular distribution of light reflected by the target, the angular distribution detector detecting the angular distribution of reflected light on the recording medium and on the detection sample image formed on the recording medium, the image forming unit forming an output image on the recording medium by adjusting imaging conditions based on the angular distribution of reflected light on the recording medium and the detection sample image detected by the angular distribution detector.