Image forming apparatus for regulating removal of developer storing portion, and regulation releasing method

An image forming apparatus includes an image forming portion, a supply processing portion, and a second release processing portion. The image forming portion includes a storing portion that stores developer, and forms an image by using the developer stored in the storing portion. The supply processing portion supplies the developer to the storing portion from a developer storing portion attached to an attachment portion, when a storage amount of the developer in the storing portion is less than or equal to a first threshold. The second release processing portion releases regulation on a removal of the developer storing portion when an expected amount of developer to be used by a user is greater than or equal to a reference value that is determined based on a remaining amount of the developer in the developer storing portion attached to the attachment portion.