In an image forming apparatus mountable a detachable unit mounting a memory in a main body of the apparatus, a memory-access-reservation control unit for accepting a request of an access with respect to a nonvolatile memory provided in a process cartridge in which a photosensitive drum, a toner and the...http://www.google.de/patents/US6634817?utm_source=gb-gplus-sharePatent US6634817 - Image forming apparatus
