With respect to a job input to a printer, a job information management unit in a computer obtains information about a ratio of a color area in each page of the input job from the printer before the information is overwritten and stores the obtained information together with job identification information in a job information storage unit. Further, if information which is not recorded by another computer is included in a color information list of the printer regarding a copy job or a FAX job, the job information management unit obtains the information about a ratio of a color area in each page of the copy job of the FAX job from the printer.