Patent ID: 7460800

Claim:
An image forming apparatus comprising: a paper feed portion for storing paper and selectively feeding and conveying the paper, sheet by sheet, from a stack of paper stored therein; a printing portion for performing a printing process for transferring image information of an unfixed developer to paper; a fixing portion for fusing and fixing the image information formed of the unfixed developer to the paper; a paper discharge portion for discharging the paper with the image information fused and fixed thereon to the outside of the apparatus; a history storage portion configured to store a usage history involving a number of prints of the image forming apparatus; and, a processing time controller configured to change a time of the pre-processing operation before or a time of a post-processing operation after a printing process of the printing portion, based on the stored usage history so as to exclude the influence of the unfixed developer on the printing process, wherein the usage history stored in the history storage portion is defined by separately counting the number of times the image forming apparatus has been used for printing operations for a single print and the number of times the apparatus has been used for printing operations for multiple prints, wherein, in comparison between the printing process operation time of the image forming apparatus calculated based on the usage history stored in the history storage and a reference time for change, the processing time controller sums up the printing process operation time (T 1 ), the pre-processing operation time (T 2 ) and the post-processing operation time (T 3 ) of image forming apparatus separately and makes comparison based on the following formulae, and determines whether the pre-processing operation time or post-processing operation time should be made longer or shorter than the normal processing operation time: Σ( T 1)≦(Σ( T 2)+Σ( T 3)) (1) Σ( T 1)>(Σ( T 2)+Σ( T 3)) (2) where when the relation (1) holds, the printing process operation time is determined to be equal to or longer than the predetermined reference time for change; and when the relation (2) holds, the printing process operation time is determined to be shorter than the predetermined reference time for change.