| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high-grade color image, in which the concentration of the image is constant from the begining of the image formation, by detecting the concentration of a reference image in order to obtain the quantity of the supply of the toner and feeding back this result to other controllers, thereby maintaining the concentration of the toner at a constant value. SOLUTION: A patch image as a reference image for detecting the concentration is formed on a photo sensitive material drum 40. The light is irradiated from a light emitting part 73a of an LED of a concentration sensor 73, and the reflected light received by a light receiving part 73b made up of a photoelectric transfer element or the like in order to detect the actual concentration of the patch image. The output signal thus detected is supplied to an input port on one side of a comparator 75 and compared with the standard signal, which comes from a standard voltage signal source 76, which corresponds to the standard concentration of the patch image, and which is supplied to the other side of the comparator 75, in order to obtain the difference between the two and to supply the output signal on the difference of the concentration to the CPU 67. The output signal on the difference of the concentration is used for the control of the supply of the toner to a developer 43 within a developing machine 44, which is conducted by both a developer reflecting ATR and a video-count ATR. |
