IMAGE PROCESSING APPARATUS, CONTROL METHOD THEREOF, AND COMPUTER PROGRAM
FIG3 is a diagram illustrating a recording head according to a first embodiment  FIG2 is a block diagram illustrating a halftone processing unit according to the first embodiment
On the basis of the halftone image data, which is received from the image processing apparatus 10 through an input terminal 201, the image forming apparatus 20 forms an image on a recording medium such as recording paper by forming dots on the recording medium while moving the recording medium relative to a recording head 203. Here, the recording head 203 uses an ink jet recording method, and includes a recording-element array in which a plurality of recording elements capable of ejecting ink are arranged. FIG3 is a diagram illustrating an example of the configuration of the recording head 203. Although the recording head typically includes nozzles for four types of ink, namely cyan (C), magenta (M), yellow (Y), and black (K), only black (K) is illustrated for the sake of simplicity. The recording head is a long line head in which the nozzle arrangement covers the entire range of the rendering region in the recording medium width direction (the x direction), which is perpendicular to the recording medium feed direction (the y direction), and a printed image is formed by ejecting ink while moving the recording medium relative to the head once. A head drive unit 202 generates a drive signal for controlling the recording head 203 on the basis of the halftone image data. The recording head 203 records the actual ink dots on the recording medium, on the basis of the drive signal. It is assumed that the recording elements in the cyan (C), magenta (M), and yellow (Y) recording heads are arranged parallel to the black head that is illustrated.  FIG2 is a block diagram illustrating the configuration of the halftone processing unit 103 in detail. The halftone processing unit 103 converts the image data stored in the input image buffer 102 into binary (1-bit) data for each nozzle group, and outputs the converted data. To achieve this processing, the halftone processing unit 103 includes a comparator 1031, a dither matrix 1032 (constituted by ROM or the like), and an output data generator 1033.
block diagram, diagram
103
halftone processing unit
1031
comparator
1033
output data generator
1032
dither matrix
102
input image buffer
['1. An image processing apparatus that generates image data for an image forming apparatus, the image forming apparatus having a recording head in which a plurality of recording elements are arranged in a first direction, and that forms an image on a recording medium by ejecting ink from the recording elements of the recording head toward the recording medium while the recording medium is fed relatively in a second direction that is perpendicular to the first direction, the image processing apparatus comprising: acquiring means for acquiring multi-valued input image data; correction processing means for executing a density unevenness correction process in accordance with properties of each of the recording elements; and conversion means for converting the input image data into halftone image data indicating the presence/absence of a dot, by using a dither matrix, wherein the dither matrix is a dispersive dither matrix, and has characteristics in which when input image data having a uniform tone is converted into binary halftone image data, the same number of dots are present at each of locations in the first direction, in a predetermined range in the second direction, for a tone, among the tones which the input image data can take on, that is subject to the density unevenness correction process.']