Patent ID: 7469821

Claim:
An image forming apparatus, comprising: a reading section which reads out information stored in a storage medium of a replaceable processing unit, which is mounted to the image forming apparatus as a part of image forming function; a display section for displaying information; reading controlling means for causing the reading section to read display information regarding product liability, which is stored in the storage medium; a first storage section which at least stores comparison information used for identification of the display information read by the reading section; comparing means for comparing the display information read by the reading section with the comparison information stored in the first storage section; display controlling means for displaying in the display section one or both of the display information and a comparison result given by the comparing means; operating means for carrying out a predetermined operation according to the comparison result given by the comparing means; and estimating means for estimating exchange timing of the processing unit, wherein when the processing unit is an unauthorized product, the operating means causes estimation for exchange timing to be earlier than that of the authorized product so as to prompt the user to replace the processing unit early.