Image reading apparatus, image forming apparatus and computer readable information recording medium

A non-transitory computer readable information recording medium tangibly embodying an image data processing program which, when executed by a computer processor, performs an image data processing method used by an image reading apparatus, which comprises an image reading part having image sensors disposed in such a manner that reading parts of adjacent ones of the image sensor overlap in a main scan direction each other by a predetermined number of pixels in a staggering manner, said image processing method comprises:

• a joint part correcting step of correcting image data obtained from the reading parts of the image sensors in a range in which the reading parts of the adjacent image sensors overlap in the main scan direction, wherein:
• the joint part correcting step comprises a first step of calculating corrected image data for each pixel in the range in which the reading parts of the adjacent image sensors overlaps in the main scan direction, for correcting the image data for a position shift less than an amount corresponding to one pixel in the main scan direction of the image sensor, wherein a correcting method is determined in such a manner that a position shift amount to be corrected increases in a step-by-step manner as a position moves from a base portion to an end portion in the range in which the adjacent image sensors overlap in the main scan direction;
• a second step of multiplying the image data corrected by the thus-determined correcting method by a weighting factor which is determined according to a position in the main scan direction in the adjacent image sensors;
• and
• a third step of adding the image data obtained from the first part and the second part, together between the adjacent image sensors for each corresponding pixel to generate image data of the range in which the adjacent image sensors overlap in the main scan direction.