Abstract: An image processing apparatus is provided that can accurately and rapidly perform color/monochrome judgment for print image data. In the image forming apparatus, a command analyzing unit interprets externally received PDL data, and a first color/monochrome judging unit performs the color/monochrome judgment based on an attribute of an image object. When a data type of the attribute is not raster image data and color information is monochrome, it is immediately judged that the image is monochrome. Only when the first color/monochrome judging unit judges that the image is color, a second color/monochrome judging unit performs the color/monochrome judgment every time a rendering unit generates band data. If at least one pixel of color data exists, it is judged that the image is color. With such a configuration, the color/monochrome judgment can be performed accurately and rapidly.

Abstract: An image processing apparatus is provided that can accurately and rapidly perform color/monochrome judgment for print image data. In the image forming apparatus, a command analyzing unit interprets externally received PDL data, and a first color/monochrome judging unit performs the color/monochrome judgment based on an attribute of an image object. When a data type of the attribute is not raster image data and color information is monochrome, it is immediately judged that the image is monochrome. Only when the first color/monochrome judging unit judges that the image is color, a second color/monochrome judging unit performs the color/monochrome judgment every time a rendering unit generates band data. If at least one pixel of color data exists, it is judged that the image is color. With such a configuration, the color/monochrome judgment can be performed accurately and rapidly.

Abstract: An image forming apparatus including a bit map data generating section for generating binary dot data for each color from image data, an image memory for storing the dot data, an edge dot discriminating section for discriminating edge dots positioned in an edge section, such as a curved-line section, a slanted-line section of characters, graphics, photo images, etc. in dot data for black stored in the image memory, and a dot modulating circuit for modulating the dot data so that the edge dots and printing dots other than black ones become smaller than black printing dots other than the edge dots. With this arrangement, since linear tone can be obtained even in a section with a deep color, excellent tone can be obtained in multi-color printing such as full-color printing. Therefore, reproducibility of tone of binarized image data can be improved, and jaggedness in an edge section can be improved so as to have a smooth line.