Image forming apparatus with image adding function

Claim 1

An image forming apparatus with an image adding function, said apparatus comprising: an original table on which an original is placed, the original being capable of transmitting light therethrough; light-transmitting means for emitting the light onto the original placed on said original table while the light is moved therealong; additional image formation specifying means for specifying a desired additional image formation, an additional image formed by the additional image formation being comprised of pixel elements having a variable width and length which are determined at a desired portion of the original on said original table when the light emitted from said light-transmitting means moves; image forming color specifying means for specifying at least a preselected first image forming color other than black and a second image forming color of black in correspondence with formation of first and second images; first controlling means for calculating positional data of an image area outside the desired additional image formation specified by said additional image formation specifying means, based on movement of the light emitted by said light-transmitting means, and for storing the calculated positional data; second controlling means for receiving and storing data of the first and second image forming colors which are specified by said image forming color specifying means in correspondence with formation of the first and second images; original scanning means, movable along said original table, for optically scanning the original placed on said original table and for forming a reflected light image thereof; image forming means for focusing the reflected light image obtained by said original scanning means, developing the image, and forming a corresponding image on an image forming medium by selectively driving a plurality of developing units of different colors; image forming medium feed-back means for selectively feeding back said image forming medium on which an image is formed by said image forming means; image erasing means for selectively erasing the image formed by said image forming means; third controlling means for enabling said image erasing means and said image forming means, and disabling said image forming medium feed-back means and said original scanning means during formation of the first image; fourth controlling means, operable during formation of the second image, for reading out positional data of an image portion outside the desired additional image formation from said first controlling means and the data of the first image forming color from said second controlling means, and for supplying the readout data to said image erasing means, thereby allowing said image forming means to form a desired additional image in a corresponding portion on said image forming medium; fifth controlling means for disabling said image erasing means and enabling said image forming medium feedback means, said original scanning means, and said image forming means during formation of the second image; and sixth controlling means, operable during formation of the second image, for reading out the data of the second image forming color from said second controlling means and for supplying the readout data to said image forming means, thereby allowing said image forming means to form the image of the original in the second image of the original in the second image forming color on the image forming medium, which has been fed back.