Patent ID: 7697163

Claim:
An image processing apparatus comprising: a conversion execution section that converts input image data pixels, including red, green, and blue components, pixel by pixel, into output image data pixels, including cyan, magenta, yellow, and black components, by executing a first color conversion suitable for a black edge and by executing a second color conversion not suitable for the black edge; a black edge determination section that determines whether each input image data pixel of the input image data pixels is a black edge pixel forming the black edge, based on peripheral pixels of an input image data pixel, by determining whether the input image data pixel satisfies both a condition that the input image data pixel forms an edge and a condition that a color of the input image data pixel is black; a dot detection section that determines whether each input image data pixel is a dot pixel, by detecting dot information of the input image data pixel based on the peripheral pixels of the input image data pixel; and a conversion instruction section that instructs the conversion execution section, based on a result determined by the black edge determination section and a result determined by the dot detection section, to convert the color components of the input image data pixel determined as the black edge pixel by executing the first color conversion suitable for the black edge; wherein: when the input image data pixel is determined as the black edge pixel and is determined as the dot pixel, the conversion instruction section instructs the conversion execution section to execute the second conversion not suitable for the black edge and to not execute the first conversion suitable for the black edge, the first color conversion converts the image data of the cyan, magenta and yellow components into the image data of the cyan, magenta, yellow and black components, and the second color conversion converts the image data of the cyan, magenta and yellow components into the image data of the cyan, magenta, yellow and black components, the first color conversion generates a black component from the cyan, magenta and yellow components and subtracts a product of the black component multiplied by a coefficient of 1 or more from the cyan, macienta and yellow components, the second color conversion generates a black component from the cyan, magenta and yellow components, and the second color conversion subtracts the black component from the cyan, magenta and yellow components, and an amount of the cyan, magenta and yellow components that is generated by the first color conversion is zero or smaller than that of an amount of the cyan, magenta and yellow components generated by the second color conversion.