An image forming apparatus includes a photoconductor, an optical scanner, a developing device, a density detector, and an exposure corrector. The photoconductor is rotatable in a direction of rotation. The optical scanner includes a light source, and drives the light source to form a latent image on a surface of the photoconductor. The developing device develops the latent image to form an image. The density detector detects variation in density of the image in the direction of rotation of the photoconductor. The exposure corrector generates exposure correction data for the optical scanner to reduce the variation in density. The exposure corrector adjusts output of the optical scanner according to the exposure correction data at a time different from a time when the exposure corrector updates the exposure correction data.