Example embodiments are directed to an apparatus and method of image processing. Moving speed control processing performed by a control unit causes an image reading portion to move the position of a reading line in a sub-scanning direction of a document, to read an image on the document in the main scanning direction, and to output the image data on the read line. A read image correction portion converts the image data characteristics to data characteristics that are predetermined at the time of accumulation of the image data, and accumulates the converted image data. Then, an image processing portion converts the accumulated image data characteristics into device characteristics of a device to which the image data is output, and outputs the converted image data to an image writing portion or to the device to which the image data is output, via an external I/F control unit.