| 摘要 |
PURPOSE:To obtain a toner layer having an optimum layer thickness on a donor by bringing a conductive member into contact with the toner layer, impressing a specified voltage between the member and the donor, detecting the current value in the thickness direction of the toner layer, and setting the reference current value threof at the value at which the optimum thickness of the toner layer is obtained. CONSTITUTION:If the current value in the thickness direction of a toner layer is larger than a reference current value, the toner layer is thinner than a reference thickness; therefore, the press-contact force of a doctor is weakened. Conversely, when the current value is smaller than the reference current value, the press-contact force of the doctor is increased. The doctor 3 which itself is conductive is used for this purpose as a conductive member to be brought into contact with the toner layer. The current flowing in the thickness direction of the toner layer from an electric power source E1 through the doctor 3 is detected with a current detection circuit 11, and a regulating mechanism for press-contact force, for example, a solenoid mechanism, is operated by the detected current value, and the press-contact force of the doctor 3 with the donor 1 is adjusted by the same so that the current value detected with the circuit 11 coincides with the reference set value. |
