| 摘要 |
PURPOSE:To obtain the title apparatus not affected not only by the density or inclination of a registering mark but also by the change in the feed speed of the printed matter, by automatically extracting the registering mark on the basis of the differential signal of light receiving output obtained from each of light receiving parts. CONSTITUTION:When the light receiving parts 11-14 of a light receiving element 1 detect marks 20-23, signals (a)-(d) are outputted from a converter circuit 15 on the basis of the current outputs from the light receiving parts. The light receiving parts 11, 12 detect the same position of the marks with certain time difference. The light receiving parts 13, 14 also detect the other same position of the marks with certain time difference. These signals (a), (b) and (c), (d) are given to differential circuits 16, 16' to obtain values (b-a)=e and (d- c)=f. These signals (e), (f) are given to peak detection circuit 17, 17' to form pulses (g), (h) showing peak points. |
