An image formation device has an image carrier in which are formed latent
images, and a development device into which development units housing
toner are detachably installed. When development units with a plurality
of colors are installed in respective installation positions of the
development device, the image formation device operates in color printing
mode, and when at least one black development unit is installed in any
among the plurality of installation positions, and at least one among the
development units with the colors other than black is not installed, even
if at least one development unit in the plurality of colors other than
black is installed, the image formation device operates in monochrome
printing mode. When any of the C, M, and Y development units is removed
from color mode state, the image formation device operates in monochrome
printing mode.