| 摘要 |
PURPOSE:To monitor imperfect collation with high reliability without any influence of variations in distance between folded leaves of paper and a sensor, by using a sensor having two light sources and a photodetector. CONSTITUTION:A paper surface to be measured is irradiated by two light sources, and its reflected light is received by a photodetector to cancel variations in sensitivity due to fluctuations of a paper surface position. For example, when imperfect collation is monitored by using a sensor a fitted under the stack table 3 of a collating machine, two light sources B and B' are used in the sensor A to irradiate irradiated surfaces (d)-(c) among irradiated surfaces (f)-(g) with light from both the light sources, obtaining double brightness. When the paper surface moves as shown by an arrow 4, the distance between a photodetector (not shown in figure) near the light sources and the paper surface increases, but area having double brightness also increases, so that the both cancel mutually. Consequently, the quantity of light that the sensor A receives is unchanged, and imperfect collation is monitored with high reliability. |
