Patent ID: 8190039

Claim:
An image forming apparatus for forming an image using a replaceable image formation unit, comprising: an abnormality signal input device configured to input a signal representing occurrence of abnormality in one of an output image and the image forming apparatus recognized by an operator; a unit specifying device configured to specify a replacement unit to be replaced to resolve the abnormality upon receiving the signal from the abnormality signal input device; a notification device configured to notify the operator of information related to the replacement unit in accordance with a result of the specification executed by the unit specifying device; and a lock mechanism configured to lock and prohibit the replacement unit from being removed from the image forming apparatus, said lock mechanism including a moveable member, wherein a controller causes the moveable member to be disposed at a position that prohibits the replacement unit from being removed through an opening in the image forming apparatus while the replacement unit is aligned with the opening, and the controller causes the moveable member to be disposed at another position that allows the replacement unit to be removed through the opening in the image forming apparatus that is aligned with the replacement unit in response to the replacement unit being specified for replacement by the unit specifying device.