| 摘要 |
PURPOSE:To detect toner density with high precision on a certain measurement condition by changing the oscillation characteristic of a detector in a developer vessel in accordance with a specific gravity of the developer to detect the toner density. CONSTITUTION:A detector 9 consisting of an electrostrictive oscillator is arranged in a developer vessel 4 where a developer 2 containing a carrier and a toner is stored. The oscillation characteristic of the detector 9 is changed in accordance with a specific gravity of the developer 2, which is brought into contact with the oscillating face, to detect the density of the toner included in the developer on a basis of the change of the oscillation characteristic. |
