| 摘要 |
PURPOSE:To perform setting of proper developing bias voltage by disposing members which detect the colors and densities of the ground colors of an original to a photodetecting part. CONSTITUTION:The output signals of level discriminating circuits 7A, 7B respectively emit high levels to the terminals L, H' alone and emit low levels to all the other terminals M, H, etc.; therefore, these signals are inputted via latching circuits 8A-8F to selecting logic circuits 9, so that only the output of the logic circuit 9C is made the signal of a high level and the outputs of all the other logic circuits are made the signals of a low level. Hence, the combinations of the output signals of the circuits 9 corresponding to the kinds and varying densities of the colors of the original ground colors placed on an original platen are obtained from a series of operations. ON and off of switching transistors 10A-10I of a developing bias voltage selecting circuit 10 are accomplished by these combined output signals. Thereby, proper developing bias voltage can be set. |
