| 摘要 |
PURPOSE:To improve the follow-up ability of developer concentration and to obtain an excellent image by predicting toner consuming quantity and correcting toner replenishing quantity. CONSTITUTION:When a copy button is depressed, reflected light from a part of an original on a platen glass is received by a photodetector 2 through an optical system 20. Then, an EE processing part 22 samples the reflected light quantity received by the photodetector 21, and a histogram is obtained by checking the sampled reflecting quantity with a judging standard one by one. The EE processing part 22 calculates the area of black character parts from the histogram and a blackening area rate which is the rate of whole original area to the area of the black character parts. The toner consuming quantity is predicted from the blackening area rate. A correcting means calculates corrected concentration data Vc which is corrected by mean concentration data Vs and blackening area rate data Ns from a blackening area detecting means. |
