| 摘要 |
PURPOSE:To obtain a copy of a positive picture by measuring the quantity of light transmitted through a picture recorded on a microfilm, by comparing this measured value with a reference value to discriminate between the negative and positive of the recorded picture, and then by changing the polarity of the charge of a charger with the discrimination signal. CONSTITUTION:When the voltage of the output signal of photoelectric converting element 30 is higher than the voltage of the 1st reference signal generated by the 1st reference voltage generator 32, a signal of logic [1] is outputted. When the voltage of the output signal of element 30 is lower than the voltage of the 2nd reference signal generated by the 2nd reference voltage generator 34, a signal of logic [1] is generated. Namely, when the quantity of light inputted to element 30 is greater than a reference value, a decision on a microfilm with positive pictures is made to output the [1] signal from comparing circuit 33, and when less, a decision on a microfilm with negative pictures is made to output the [1] signal from comparing circuit 35. According to the discrimination signal, polarity change-over switch 41 is changed over and from high-voltage generation source 42, a high voltage of polarity equal to or different from that of developing toner of a processor is applied to charger 13 to charge copying paper. |
