| 摘要 |
PURPOSE:To detect accurately the density of each kind of particles in a developer and detect the density of each kind of toner by measuring the potential of the developer on a sleeve and detecting the mixing ratio of respective particles in the developer. CONSTITUTION:A device performs dichroic development on magnetic brush basis. The developer consists of black magnetic toner T1 electrostatically charged positively and red magnetic toner T2 electrostatically charged negatively. A toner density reference value is set to a 1:1 mixing ratio; the toner T1 is stored in a tank 15b and the toner T2 is stored in a tank 15a. The potential of the developer is measured by a surface potential detector 17 during the operation of the device and the measured value is integrated by an integration circuit 18 for 80sec. This integral value is compared with the reference value when the mixing ratio of the toner T1 and toner T2 is 1:1; when the value is larger than the reference value, a decision on a decrease in the density of the toner T2 is made to rotate a supplement roller 16a by a specific extent by a control driving system 19, and when not, a roller 16b is rotated similarly to supplement fresh toner into a developing tank 10. |
