| 摘要 |
PURPOSE:To provide a toner concentration controlling method by which toner concentration is accurately maintained even when the carrier of two-component type developer is changed with the lapse of time. CONSTITUTION:In an image recorder where an electrostatic latent image formed on a photosensitive drum 8 is developed with the two-component type developer 23 and then recorded on a copying paper 12, magnetic field is generated and applied to the developer 23, and the toner concentration is controlled by using a toner concentration sensor 28 for detecting the change of the magnetic permeability of the developer 23, then control voltage Vcont for controlling the intensity of the generated magnetic field to the sensor 28 is changed by specified voltage Vcont every time the recorded number of copying papers 12 is increased by specified number. |
