An image forming apparatus includes: an image carrier; a light source configured to emit light for exposing the image carrier; a controller configured to control a light intensity of the light source; a reference current generator configured to generate a reference current based on a target light intensity of the light source, the target light intensity being set by the controller; a correction current generator configured to generate a correction current for correcting the reference current based on an amount of correction that is set by the controller, and on the target light intensity; and a driver configured to drive the light source using a drive current that corresponds to a difference between the reference current and the correction current.

A setting unit of a controller mounted on a control board sets a first mode for generating, from image data, PWM data indicating a pattern for causing an LD to emit light and transmitting to a laser driving board, or a second mode for transmitting to the laser driving board image data prior to generation of the PWM data. A data conversion unit, in the first mode, converts inputted image data into N pieces of PWM data respectively corresponding to N LDs, and in the second mode, converts inputted image data into image data for each scanning line. A P/S conversion unit converts data outputted from the data conversion unit from a serial format into a parallel format, and transmits the converted data to the laser driving board as control data.