Patent ID: 7324244

Claim:
An image forming apparatus, comprising: a first image reading portion including a plurality of line sensors used to read a color image at a first reading density and output red, green and blue image signals having a first density; a second image reading portion including at least one line sensor used to read a monochrome image at a second reading density higher than the first reading density and output a monochrome image signal having a second density higher than the first density; a first image processing portion which processes the red, green and blue image signals processed and outputted by the first image reading portion, the first image processing portion including a color conversion portion which converts the red, green and blue image signals to cyan, magenta and yellow color signals representing densities of recording color toner; a second image processing portion which processes the monochrome image signal processed and outputted by the second image reading portion; a segmentation portion which includes an edge detection portion that detects whether an edge is present for each of color components of the cyan, magenta and yellow color signals, a dot detection portion that detects whether a dot component is present from the monochrome image signal, and a chroma judgment portion that judges chroma from the red, green and blue image signals, and which discriminates a segment based on outputs from the edge detection portion, the dot detection portion and the chroma judgment portion, and outputs a segmentation signal indicative of an attribute of an image; and a signal switching portion which outputs at least one of a first image signal processed and outputted by the first image processing portion and a second image signal processed and outputted by the second image processing portion based on the segmentation signal.