COLOR BALANCE CONTROL METHOD FOR MULTICOLOR IMAGE FORMING DEVICE

摘要

PURPOSE:To obtain excellent color balance even in case of the fluctuation of environment and to prevent the occurrence of mechanical abnormality by controlling exposure so that the detected value of toner adhesion quantity to an original on a half tone part by a photoelectric sensor is adjusted to the reference concentration of respective colors. CONSTITUTION:The pattern 19a of the half tone part and the pattern 19b of a high concentration part are provided. By lighting with a lighting device 3, as pattern image is formed on a photosensitive body 8 by means of an optical device 7 under exposing conditions actually used and turned into a toner image by means of a developing device 10. The concentration of the toner image in an unfixed state is detected by the photoelectric sensor 18 arranged on the downstream side of a transferring position so as to obtain the output of a voltage corresponding to the concentration. In case of the fluctuation of concentration, the output from the photoelectric sensor is controlled by an exposure control circuit and the developing condition of the developing device is corrected if necessary. Thus, the image density can be stabilized under all the conditions and the image with good color balance can be obtained. The mechanical abnormality and an abnormal image can be prevented.