| 摘要 |
PURPOSE: To provide an image forming device capable of preventing fluctuations of a developing density by uniformly controlling the concn, of toner in a developing device, without increasing cost and the method for controlling the concn. of the toner in the developing device. CONSTITUTION: The differences between the potential by electrification of an image carrier 1 and a developing bias voltage and between a latent image potential and a developing bias potential are controlled to a prescribed value by both of a charging voltage controller 19 and a bias voltage controller 22 or a light quantity controller 20 controlling the light quantity of image light emitted from an exposing device 3. After that, the image carrier 1 is irradiated with the image light for forming the reference patch of a prescribed area ratio from the exposing device 3 and the reference patch is developed by the developing device 4, to measure the potential of the formed toner layer by a potential measuring means 11. Further, the value of the measurement is compared with a reference value by a CPU 23 and operation for supplying the toner into the developing device or consuming the toner is controlled based on the result of the comparison. Thus, the concn. of the toner in the developing device can be kept almost constant. |
