1. An image forming apparatus comprising: a plurality of image carriers on each surface of which an electrostatic latent image is formed, each of the image carriers being attachable and detachable; a plurality of development units each adhering a toner to the electrostatic latent image carried on a corresponding one of the image carriers, the development units adhering toners that are different from each other, a plurality of transfer units that transfer the toners adhering to the image carriers to a recording medium; an order detection unit that detects an arrangement order of the loaded image carriers; an image formation condition setting unit that sets an image formation condition for at least one of the developing units and each of the image carriers based on the arrangement order detected by the order detection unit; a mode setting unit that sets a mode of image formation; an arrangement order setting unit that sets an expected arrangement order of the image carriers based on the mode set by the mode setting unit; and an alerting unit that informs of an abnormality in a case where the arrangement order detected by the order detection unit and the expected arrangement order set by the arrangement order setting unit are different.