Image forming apparatus having functional redundancy system

摘要

An image forming apparatus is provided comprising means (5) for storing an objective model of the apparatus. The model includes specification of states (S) defined by physical parameters of the operational components (33, 36) of the apparatus. Also specified are behaviours (B) defined as changes in the states and functions which result from the various behaviours. The model is referred to as a function-behaviour state (FBS) diagram. Control means operate the apparatus under a control sequence for a particular function. When the function of the apparatus is defect, a substitute control sequence is activated. Redundancy system control means (8 - 14) are adapted to operate the apparatus under the substitute control frequency, whereby a lost function of one component can be replaced by a substitute function provided in another component.