US Patent 7642024 Image-forming apparatus and image-forming process

An image-forming apparatus comprises: an image carrier; a charging unit; a latent image forming unit; a developing unit that uses a toner maintaining a non-color-developing state when provided with coloring information through exposure to light; a coloring information providing unit that provides the toner image with coloring information by exposing the toner image to light having a predetermined wavelength determined depending on the color not to be developed based on color component information of image data; a transfer unit; a fixing unit; a color-developing unit that develops a color of the toner image provided with the coloring information; and a control unit that controls the coloring information providing unit to expose a background region on the image carrier to light having a predetermined wavelength for preventing color development of the toner.