An example image forming apparatus includes a light emitter to emit a plurality of light beams in a first direction perpendicular to a light emitting direction of a display and a second direction perpendicular to the first direction and the light emitting direction, a light receiver, a first processor to determine a touch input coordinate of a user based on a variation amount of each of the plurality of light beams received by the receiver, and a second processor to control the display and the image former using the determined touch input coordinate. The first processor may suspend determination of the touch input coordinate in response to an optical change being detected only in one direction within a preset first time. The example image forming apparatus may prevent a touch error, such as a touch error due to frustrated total internal reflection.