Image forming apparatus having locking device with failure detection

An image forming method comprising:

• obtaining a detection result of a remaining amount of a consumable contained in a replacement in an image forming apparatus;
• determining that the remaining amount of the consumable is not greater than a predetermined threshold;
• determining that the image forming apparatus is powered on;
• determining that a cover is closed;
• and
• detecting an unlocking failure of a locking device in the image forming apparatus by determining whether or not the locking device switches to an unlocking state in which the locking device unlocks an open-close member configured to open and close an opening of a storage storing the replacement, in response to detecting that the cover is closed and determining that an amount of the consumable contained in the replacement is not greater than the predetermined threshold.

An image forming method comprising:

• calculating a remaining amount of a consumable contained in a replacement in an image forming apparatus;
• determining that the remaining amount of the consumable contained in the replacement is not greater than a predetermined threshold;
• determining that the image forming apparatus is powered on;
• and
• in a case in which the image forming apparatus is powered on, detecting a locking failure of a locking device in the image forming apparatus by determining whether or not the locking device retains a locking state in which the locking device locks an open-close member configured to open and close an opening of a storage storing the replacement.