An image forming apparatus including a conveying unit for conveying a document, on which an image is recorded, along a predetermined conveying path, a scan unit that is disposed on the conveying path of the document for scanning the image recorded on the document, and a control unit for controlling the conveying unit and the scan unit. The control unit includes a main circuit board that controls operations of the scan unit and converts the scanned image into digital image information, and a sub-circuit board that controls operations of the conveying unit, and wherein the sub-circuit board includes a high voltage signal area on which a high voltage signal is routed, and a low voltage signal area on which a low voltage signal is routed.