IMAGE FORMING APPARATUS, IMAGE FORMING METHOD, AND PROGRAM

PROBLEM TO BE SOLVED: To ensure the number of samples of detected concentration values to improve the accuracy of detection of toner concentration, as well as eliminate influence on continuous printing operation to maintain the productivity, even when the intermediate transfer body is transferred at a low rate.SOLUTION: An image forming apparatus includes: a Y-pattern generation section 60 that forms a reference toner pattern for each photoreceptor and transfers the pattern onto an intermediate transfer belt 2; an M-pattern generation section 61; a C-pattern generation section 62; a Y-pattern detection sensor 10 that detects the concentration of a reference toner pattern formed through transfer onto the intermediate transfer belt 2; an M-pattern detection sensor 11; a C-pattern detection sensor 12; a rate control section 63 that changes a motion rate of the intermediate transfer belt 2 to a predetermined rate; and a concentration adjustment control section 52 that detects the concentration of the reference toner pattern after the motion rate of the intermediate transfer belt 2 is changed to the predetermined rate by the rate control section 63, and corrects the detected concentration value.