1. An image processing apparatus capable of executing at least one of a plurality of image processing jobs including a copy job, a FAX job, a print job, and a scan job, the image processing apparatus comprising: a first receiver operable to receive one or more of the plurality of image processing jobs; a second receiver operable to receive one or more maintenance jobs necessary for maintaining the image processing apparatus; a job register operable to register therein the received image processing jobs and the received maintenance jobs; and a controller operable to control execution of the registered image processing jobs and the registered maintenance jobs, with reference to the job register, wherein if a maintenance job and an image processing job that are executable in parallel with each other are registered in the job register, the controller executes the maintenance job and the image processing job in parallel with each other.