Patent ID: 6466335
Filing Date: 2002-10-15
Classification: H04N

Abstract:
An image forming apparatus having a recording head on which a plurality of recording elements are arranged, to record pixel dots on a recording medium relatively moved in a direction substantially orthogonal with a direction of arrangement of the recording elements of the recording head and to thereby form two-dimensional images, comprising:setting means for setting a plurality of kinds of pairs of control signals to be used to change a size of the dot on the basis of gradation information, in response to a kind of an image to be formed on the recording medium; selecting means for selecting a desired pair of control signals set by the setting means in response to the kind of image to be formed on the recording medium; a head driving unit for changing a size of the pixel dot recorded on the recording medium by driving the recording head in accordance with one control signal corresponding to the gradation information, of the pair of control signals output from the selecting means; and edge portion interpolating means for interpolating an edge portion of input image data, wherein the pairs of control signals are set by the setting means in response to the formed image, which is any one of an image of a character, a line drawing and the like, and a natural image, and wherein when the image to be formed on the recording medium is a natural image, the head driving unit changes a size of the pixel dot of the natural image on the basis of each pair of control signals selected by the selecting means, and when the image to be formed on the recording medium is an image of a character, a nine drawing and the like, the head driving unit changes a size of the pixel dot of the image subjected to the interpolation of the edge portion by the edge portion interpolating means on the basis of each pair of control signals selected by the selecting means.