1. An image processing apparatus for processing pieces of color image data each including a plurality of sub-pieces of color image data pertaining to the plurality of color components respectively comprising: initial color image inputting means for inputting an initial color image data to be processed; data dividing means responsive to the initial color image data for dividing it in respect of color components and for providing pieces of mono-color image data each corresponding to one of the sub-pieces of color image data of the piece of initial color image data, the number of the pieces of mono-color image data being equal to or larger than the number of the color components; data processing means for effecting a predetermined processing on each piece of mono-color image data to provide secondary image data; and secondary image data outputting means for providing the secondary image data, one or more pieces of mono-color image data, which belong to one of the plurality of color components, being included in the pieces of mono-color image data of the number equal to or larger than the number of the color components; and the total number of the data points of the pieces of mono-color image data being equal to the number of the data points of the piece of initial color image data while the number of the pieces of mono-color image data being equal to or larger than the number of the color components.