Patent ID: 8089639

Claim:
An image forming apparatus, comprising: an image acquisition portion which acquires image data on an image including a character; a character-periphery detection portion which detects a peripheral part of the character in the image data acquired by the image acquisition portion; an outline emphasis portion which sets the density of an image data acquired by the image acquisition portion, so that the density of the peripheral part of the character detected by the character-periphery detection portion becomes higher than the density indicated by this image data; a density change portion which sets the density of the image data so that this density gradually becomes lower from the peripheral part of the character detected by the character-periphery detection portion toward an inside thereof; an image formation portion which forms an image on a sheet of recording paper on the basis of the image data whose density is set by the outline emphasis portion and the density change portion, the image forming portion forming the image using four colored toners of black, cyan, magenta and yellow, respectively; and a toner-ratio setting portion that sets a ratio of each colored toner so that the ratio of the black toner decreases in increments, each increment being defined by a selected number of pixels, from the peripheral part of the character detected by the character-periphery detection portion toward the inside thereof, on the basis of the image data whose density is set by the outline emphasis portion and the density change portion.