connectable a connector to which predetermined ic cards are detachably applied a rewritable program memory for a main body to store a control program of the main body a cpu for controlling the respective devices and for processing input image data on the basis of the control program of the main body and an image control unit to achieve control based on control of the cpu for recording and outputting the image data which have been processed and outputting them to any one of the extension devices the extension devices interface includes control data lines for transferring and receiving control data with the extension devices and down load exclusive lines for down loading a control program of the extension device of the extension devices application_number US 7545802 A description hereinafter the preferred embodiments of the present invention will be described with reference to the attached drawings herein because the embodiments hereinafter described are mere examples of preferred embodiments of the present invention technically desirable restrictions are added to it however it is not intended to limit scopes of the present invention to the aspect of these embodiments as far as no special mention to restrict the present invention is given in the following description referring to fig1 and 2 one example of an image forming apparatus including a data control apparatus according to the present invention is shown in fig1 a digital copy machine 1 as an image forming apparatus has a main body 10 in which a printer option 40 and a facsimile option 50 are installed as optional devices extension peripheral devices 30 through an extension peripheral device interface 11 f the main body 10 includes a.