Patent ID: 7221467

Claim:
An image forming apparatus comprising: an apparatus body; image forming means at least partly implemented by a replaceable part, which is removably mounted to said apparatus body; sensing means for sensing a condition of use of the replaceable part that varies in accordance with use of said apparatus body; first writable and readable non-volatile storing means in said apparatus body; second writable and readable non-volatile storing means in the replaceable part; accessing means for accessing said first storing means and said second storing means via a shared data bus; and control means for sensing, at a time of image formation, a variation of the condition of use of the replaceable part via said sensing means, obtaining information representative of a condition after use from a sensed variation, writing, among said information, information relating to in-use operation specifications of said apparatus body in said second storing means as well as in said first storing means, said control means configured to perform a comparison of the in-use operation specifications stored between the first and second storing means, and based on the comparison to determine whether the image forming means is in an operational state.