JPS649475A - Multicolor image forming device - Google Patents

Abstract

PURPOSE:To make the density of image plane and gradation proper even if any developing is executed by setting a gap between the developing sleeve of a developing unit which executes color developing and an image carrier smaller than a gap between the developing sleeve of a developing unit which executes black developing and the image carrier at the time of developing. CONSTITUTION:A developing device 10 is a two-color developing device and an upper developing unit 11A and a lower developing unit 11B are integrated and made to be rocked. When the motor of the developing unit selected in the selection of color specifying buttons is turned, a cam 13 fixed to a shaft 12 is turned with the turning of the motor. The cam 13 presses the abutting part 14A or 14B of the device 10 so as to rock the device 10 through a spring member 15 and the developing sleeve of the developing unit 11 is stopped with a small gap previously set between the developing sleeve and the surface of a drum 2. The gap between the developing sleeve of the developing unit 11A which executes the color developing and the drum 2 is set smaller than the gap between the developing sleeve of the developing unit 11B which executes the black developing and the drum 2 at the time of developing. Thus, the density of image plane and gradation can be made proper even if any developing is executed.