Patent ID: 7509062
Filing Date: 2009-03-24
Classification: G03G

Abstract:
1. An image forming apparatus comprising: an image forming unit detachably provided in the image forming apparatus, the image forming unit including: the image forming apparatus further including a central processing unit configured to compare the guarantee information with the operation information for each one of the plurality of replaceable devices and to determine that a replaceable device is at an end of its lifetime when guarantee information corresponding to the replaceable device is approximately equal to the operation information, the control circuit being further configured to erase, from the volatile memory, the guarantee information and the operation information of the replaceable device when the replaceable device is at the end of its lifetime and to write guarantee information of a new replaceable device into the nonvolatile memory when the replaceable device determined to be at an end of its lifetime is replaced with the new replaceable device; the control circuit being further configured to read the guarantee information of the new replaceable device from the nonvolatile memory; read the operation information of the image forming unit from the nonvolatile memory; generate new guarantee information for the image forming unit based on guarantee information of the new replaceable device and an operation date of the image forming unit; overwrite the guarantee information of the image forming unit with the new guarantee information; and erase the operation information of the image forming unit in the nonvolatile memory.