1. A control device for an image forming apparatus with plural loads, comprising: a program memory for storing a plurality of programs; plural control execution units, COP0, COP1, COP2. .. COPn, for executing plural processes in accordance with at least one of the plurality of programs stored in said program memory; a monitor unit, CPU, for controlling an image forming sequence and monitoring processing operations of said plural control execution units in accordance with at least one of the plurality of programs stored in said program memory; an input unit for inputting data required for the operations of said plural control execution units; a system-bus to which said plural control execution units and said monitor unit access; and a memory unit, contents of which can be read out and written in by said plural control execution units and said monitor unit, said memory unit having a plurality of dedicated memory areas to which said plural control execution units access, respectively, and wherein said monitor unit can access each of the dedicated memory areas of the memory unit, wherein said monitor unit and said plural control execution units access said system-bus in a time-divisional manner such that said monitor unit and said plural control execution units appear to be operated in turn such that an order of access to the system bus is CPU--COP0--CPU--COP1--CPU. .. COPn, and said monitor unit selects fewer of said execution units when a task to be allocated requires a quick processing response time, wherein said monitor unit determines tasks to be executed in the image forming sequence, identifies an idle control execution unit and allocates the determined tasks to the idle control execution unit for execution, and wherein said monitor unit communicates with said plural execution control units by accessing said plurality of dedicated memory areas.