METHOD AND APPARATUS APPLICABLE TO MULTICOLOR DEVELOPING DEVICE FOR DETECTING IMAGE DENSITY

A light absorbing body is located to adjoin the back of an image carrier which is made of a light transmitting member. A latent image representative of an exclusive pattern for density detection is formed in a non-image region of the image carrier and developed by toner of any of multiple colors to become a toner image adapted for density detection. The toner image is illuminated so that image density is detected in terms of the intensity of light which is reflected by the toner image. The light absorbing body is made up of a plurality of absorbing members each having predetermined absorptivity. The absorbing members are selectively used in association with the spectral reflectivity characteristic of toner.