A method and apparatus for performing an image forming job by maintaining a cover, which covers a scan area and has adjustable transparency, in a transparent state until a job for acquiring image data of a scan object starts in an image forming apparatus. If the job for acquiring the image data of the scan object positioned in the scan area starts, the image forming apparatus converts the cover into an opaque state and acquires the image data of the scan object. If the job for acquiring the image data of the scan object is ended, the image forming apparatus reconverts the cover into a transparent state. Therefore, efficiency of a job for acquiring image data of a scan object is improved.