An image formation device has an image carrier in which is formed a latent
image and a development device in which are detachably mounted a
plurality of development units housing a developing agent. When
development units of a plurality of colors, used to form color images are
mounted in respectively predetermined mounting positions of the
development device, operation is in color printing mode; and, a
development unit of a single color among the development units of the
plurality of colors is mountable in any mounting position of the
plurality of mounting positions, and when the development unit of a
single color is mounted in any of the positions of the plurality of
mounting positions, operation is in monochrome printing mode.