An image forming apparatus including a plurality of developers and optical scanners, each of the optical scanners having a light source and a light reflecting unit and forming an electrostatic latent image on a photo conductor of each of the developers. The optical scanners have the same focusing distance from the light source to the photo conductor. The light reflecting unit of one of the optical scanners is arranged at a position different from the light reflecting unit of another optical scanner, such that intervals between the developers vary. The plurality of developers include a yellow (Y) developer, a magenta (M) developer, a cyan (C) developer, and a black (K) developer. The optical scanners include a first optical scanner, which forms electrostatic latent images on two of the developers including the black (K) developer, and a second optical scanner, which forms electrostatic latent images on the other two developers.