1. An image processing device comprising: a detecting unit to detect and distinguish a character image region from non-character image regions in input image data having a first resolution by analyzing the input image data; a generating unit to generate, only for the detected character image region, color information of a pixel converted into a second resolution from the first resolution for each N×M pixel in the character image region, the second resolution being lower than the first resolution, and generate, only for the detected character image region, shape information having the first resolution and indicating an internal arrangement pattern for the character image region constituting micropixels within the N×M pixel, wherein both of N and M are integers, and at least one of N and M is not less than 2; a first storage unit to store therein the color information; a second storage unit to store therein the shape information; and a resolution-converting unit to convert the character image region into a third resolution based on the color information stored in the first storage unit and the shape information stored in the second storage unit, the third resolution being higher than the second resolution, wherein each of the first, second, and third resolutions are correlated with a specific dots per inch (dpi) ratio for each pixel included in the character image region.