large classification a read processing system a an operating system b a control processing system c and a printing process system d the read processing system a comprises a reader 3 having an image sensor a contraction processor 4 performing a contraction process a pseudo half tone processor 5 converting data into pseudo half tone data a simple binarization processor 6 converting data into simple binarization data and an enlarging processor 7 performing an enlarging process in this arrangement the reader 3 reads documents by the image sensor and after necessary processes such as a d converting the image data is output the image data are fed to the control processing system c through the contraction processor 4 the pseudo half tone processor 5 or the simple binarization processor 6 and the enlarging processor 7 in the foregoing when the equal multiplying factors are selected by a multiplying factor selection key 10 which is described later then the image data passes through the contraction processor 4 and the enlarging processor 7 as it is on the other hand when an enlarging factor for multiplying by an integer number is selected then the image data pass through the contraction processor 4 as it is and are enlarged and processed by the enlarging processor 7 when an enlarging factor of multiplying by a non integer number is.