| 摘要 |
PURPOSE:To eliminate the need for adjustments for the variance of elements of a phtoelectric converting circuit and for their secular changes, by inspecting paper thickness after correcting the quantity of light from a light source so that every time a form is conveyed, the photoelectric converting circuit is irradiated with a constant quantity of light. CONSTITUTION:When a form 5 conveyed reaches a form detecting circuit and is detected, a circuit 7 switching input impedance lowers the input impedance of a photoelectric converting circuit 2, which becomes hard to saturate. At the same time, a circuit 8 which controls the quantity of light varies the quantity of light from a light source 1 until an input voltage level discriminating circuit 4 the output of the photoelectric converting circuit 2 coinciding with a certain reference voltage, and the light quantity control value is held equal to a value when it is detected. After a series of said operations, the form 5 is conveyed to between the light source 1 and photoelectric converting circuit 2 to inspect and discriminate the paper thickness. |
