| 摘要 |
PROBLEM TO BE SOLVED: To control the concn. of toner, based on an input control voltage, in a region except a clear region where the output of a toner sensor is reduced in a linear proportional relation to T/D(toner/developer), as well, even if the clear region is narrow. SOLUTION: In a toner concentration controller for detecting the T/D in a developing tank by the toner sensor, to control the concn. of the toner, in the clear region where the output of the toner sensor is reduced in the linear proportional relation to the T/D, the input control voltage to the toner sensor is made a prescribed value and the concn. of the toner is controlled with the output of the toner sensor. On the other hand, in an unclear region where the output of the toner sensor and the T/D show a nonlinear proportional relation, the input control voltage to the toner sensor is changed to control the concn. of the toner, based on the input control voltage, so that the output of the toner sensor of the upper or lower limit of the clear region can be obtained. |
