| 摘要 |
PURPOSE:To hold toner concentration always at the preset reference value by adding compensation to toner concentration controlling based on the stains of toner concentrating detecting pars. CONSTITUTION:The output voltage of an electric circuit 4 which amplifies the difference of the holding voltage of a sample holding circuit 3 and preset voltage and applies the same to a light emitting element 1b is applied to the base of the FET18 which is interposed between a photoelectric transducer 1a and resistance R1 and connects resistance R18 in a toner concentration detecting circuit 1. As a result, when the stains of the toner concentration detecting parts 1a, 1b increase, the output voltage level of the circuit 4 lowers and the conductivity of the FET18 increases, resulting in the decreased output voltage A of the circuit A and therefore the compensation for the stained components is applied to the output of the circuit 1 from the circuit 2 according to the reference voltage of the electric circuit 2. Thereby, the toner concentration may be held at the preset reference value. |
