Patent ID: 8620188

Claim:
An image forming apparatus to form an image on a recording medium, comprising: a first image carrier on which a toner image using black toner is formed; a plurality of second image carriers on each of which a toner image using color toner forming a color image is formed; a third image carrier on which a toner image of a special color different from the black toner and the color toner is formed; an endless rotary transfer target member, disposed opposite each of the first to third image carriers, on which the toner images formed by the first to third image carriers are superimposed; a first detachment unit to detach only the third image carrier from the transfer target member; a second detachment unit to detach the plurality of second image carriers and the third image carrier from the transfer target member; and a controller configured to selectively switch the image forming apparatus between a monochrome image mode, a normal color image mode, and a special color image mode, wherein the first detachment unit and the second detachment unit control a detachment operation based on a number of recording media continuously printed in the normal color image mode or the monochrome image mode, when switching from the special color image mode to either the normal color image mode or the monochrome image mode is performed during continuous printing of the recording media; the special color image mode is a mode in which the toner images formed respectively on the first image carrier, the plurality of second image carriers, and the third image carrier are totally, superimposedly transferred to the transfer target member; the normal color image mode is a mode in which the toner images formed respectively on the first image carrier and the plurality of second image carriers are superimposedly transferred to the transfer target member; the monochrome image mode is a mode in which the toner image formed on the first image carrier is transferred to the transfer target member and when switching from the special color image mode to the normal color image mode is performed during the continuous printing of the recording media and the first detachment unit does not perform detachment operation, a developing section to develop a latent image formed on the third image carrier is stopped.