A scanner image-processing unit includes a scanner-property adjusting unit that converts image data from a scanner unit into normalized image data and a first image processing unit that performs a first image processing on the normalized image data to generate output image data. If a controller image-processing unit that performs a second image processing on the image data from the scanner unit is connected, a configuration control unit disables an operation of the first image processing unit and controls the controller image-processing unit to perform the second image processing on the normalized image data to generate the output image data.