| 摘要 |
PURPOSE:To stably form a toner layer with a fixed layer thickness by detecting the thickness of the toner layer carried into an electrode facing part from the quantity of light reflected by the layer and controlling the magnitude of a toner layer forming bias voltage. CONSTITUTION:A photosensor 13 is disposed on a position moved by a prescribed distance X away from a position where a toner supplier 2 supplies a magnetic toner (t) to form a toner layer. The toner layer tc is irradiated with light to detect the quantity of the reflected light. A reflection density is outputted as a function of the reflected light quantity, and goes to a high level as the toner layer becomes thicker. Consequently, the reflection density is substituted for the thickness of the toner layer. An automatic voltage controller 14 controls the magnitude of a bias voltage applied to the toner supplier 2 according to data on the reflection density of the toner layer tc, which is inputted and detected by the photosensor 13. Thus, the toner layer with a fixed thickness can be stably formed all the time. |
