| 摘要 |
PURPOSE:To make a slice level correspond to magnetic powder content in magnetic ink by determining the slice level of a pulse signal obtained by scanning a pattern formed by magnetic ink, in accordance with the quantity of light of infrared rays which transmits the pattern. CONSTITUTION:Paper sheet, etc. to be inspected 1 run in the direction X, a pattern 4 formed in magnetic ink on the paper sheet etc. 1 is detected as to transmission infrared rays by a transmission infrared ray sensor 2, and its output is amplified and is inputted to a binary-coding circuit 9 through a delaying circuit 6. Subsequently, the pattern 4 passes through on a magnetic sensor 3, and a pulse corresponding to passing of the magnetic powder material particles of the pattern 4 is outputted from the sensor 3, is amplified 7, and is inputted to the circuit 9 through a BPF 8. The circuit 9 slices the output pulse of the BPF8 by a reference level corresponding to the output level of the circuit 6, binary- codes a pulse exceeding the reference level and inputs it to a CPU10. The CPU10 compares an input binary signal with a reference data of a dictionary memory 11, and verifies the validity of the pattern 4. |
