1. An optical writing controller that controls multiple light sources corresponding to different colors to expose multiple photoconductors and form an electrostatic latent image on the photoconductor, comprising: a light emitting controller to control the multiple light sources based on pixel information that comprises an image to be output and to expose the multiple photoconductors corresponding to different colors, and to control the multiple light sources to draw a predetermined pattern repeatedly in the sub-scanning direction to form stepwise patterns whose width in the main scanning direction varies with repetition; a correction value calculator to obtain a detection signal generated based on the stepwise patterns, and to determine the width in the main scanning direction of patterns for correcting based on the strength of the detection signal generated based on the stepwise patterns, and a detection signal acquisition unit to acquire a detection signal generated based on the patterns for correcting having the determined width, wherein the correction value calculator calculates a correction value for correcting a superimposing position where developed images for different colors of each of the electrostatic latent images formed on each of the multiple photoconductors are superimposed based on the detection signal generated based on the patterns for correcting having the determined width.