calibration printer 121 transmitted the results of the calibration process at an appropriate time for example when the processing of a new page is started s 205 if the results have not been transmitted the processing process is continued s 204 then if the results of the calibration process that is density converted characteristic information has been transmitted by the calibration printer 121 in step s 205 then previous density converted characteristic information is updated s 206 if the density converted characteristic information is changed when the processing of the new page is started then for example the unchanged density converted characteristic information is used to process a certain number of pages on which the same image is being printed then the changed density converted characteristic information is used for the remaining pages as a result even though the same image is being printed the reproduced colors may be changed when the density converted characteristic information is changed to prevent this the density converted characteristic information may be switched when the job received and continuously processed by the printer 101 is switched instead of immediately changing upon reception the density converted characteristic information transmitted by the calibration printer 121 since the job has been switched the switched density converted characteristic information is used for a different image now operations of the calibration printer 121 will be described in step s 203 the printer 101 requests a calibration process from the calibration printer 121 then.