An apparatus for controlling image processing comprises means for receiving printing jobs, means for spooling the jobs received, means for joining jobs to make a plurality of the printing jobs retained in the spooling means one printing job by joining them, and means for transferring the joined printing job to a printer side. With a structure thus arranged, the various processes, which have been applied per job in a conventional art, can be applied to a plurality of printing jobs as a whole by joining and regarding them as one job.