PURPOSE: To prevent the thermal deterioration of a sensitive body by providing such a constitution as situating a part of a protective member for protecting the sensitive body at the time of separating a replacing kit including the sensitive body from an image forming device between the sensitive body and a fixing device, when installed to a body.

CONSTITUTION: A replacing kit is formed of, for example, a sensitive body 12 consisting of an OPC (organic photoconductor) and a cleaning means 16, and opening parts as windows are provided in positions where transfer, electricity removal, electrification and development are conducted. When the electrifying and developing positions are turned down in the state where the replacing kit is placed, shutters 30, 31 are provided only in the transferring and electricity removing positions, and the electricity removing shutter 31 is moved on a fixing means side, when installed to the body, to protect the sensitive body 12. The arm 32 of the shutter 31 is pushed up by a rib provided on a body to open the electricity removing opening part. The pushed shutter 31 is moved between the sensitive body 12 and the fixing means to ease the heat from the fixing means.