Image forming apparatus for forming a color image, and image forming method for forming a color image

An image forming apparatus configured (a) to charge uniformly an image bearing member once, (b) to form a latent image including n levels of electric potential on the image bearing member with a single exposure, (c) to adhere a first toner on a portion of the image bearing member which has the lowest electric potential, (d) to decrease the electric potential of a portion of the image bearing member not developed with the first toner by uniformly exposing light at a first wavelength whose transmission factor is lowest for the first toner, (e) to develop using a second toner a portion of the image bearing member which has the second lowest electric potential, (f) to perform a second uniform exposure at a wavelength whose transmission factor is lowest for both the first toner and the second toner, (g) to develop using a third toner a portion of the image bearing member which has the third lowest electric potential, (h) to perform a third uniform exposure at a wavelength whose transmission factor is lowest for each of the first toner, the second toner, and the third toner, and (i) to develop a portion of the image bearing member which has the fourth lowest electric potential.