Patent ID: 7339708

Claim:
An image forming apparatus for performing at least a copying function, comprising: an engine board configured to perform image data control; an image reading unit configured to read an image of an original document to obtain image data and configured to transfer the image data to the engine board; an image forming unit configured to receive the image data from the engine board and to form the image on a transfer sheet based on the image data; a controller board detachably connected to the engine board and configured to add at least one application function to the copying function of the image forming apparatus; an operation unit configured to receive an operational instruction input by an operator of the image forming apparatus and to display information of at least the copying function of the image forming apparatus; and a parallel bus configured to connect the controller board to the engine board and to notify the engine board that the controller board is connected to the engine board when the controller board is connected to the engine board, wherein the operation unit displays the information of the copying function and the at least one application function when the controller board is connected to the engine board, and the operation unit displays the information of the copying function when the controller board is detached from the engine board, and wherein each of a plurality of display layouts of the operation unit for the copying function is substantially identical between when the controller board is connected to the engine board and when the controller board is detached from the engine board.