Provided is an image forming apparatus capable of reducing power consumption by optimizing preliminary operation of a sensor. In the image forming apparatus, when tone characteristics adjustment is instructed (Step S1003: Y), tone characteristics adjustment (Step S1006) is executed after calibration (Step S1004), while when mixed-color correction is instructed (Step S1007: Y), mixed-color correction processing (Step S1009) is executed after calibration (Step S1008). Further, in the case where mixed-color correction is executed after tone characteristics adjustment, the preliminary light emission time in calibration is set shorter than when mixed-color correction is executed without performing gray adjustment first.