| 摘要 |
<p>A light projecting section (21) irradiates light into a yarn running space (13) via a light projecting surface (32). Light exits the yarn running space (13) from a light receiving surface (33). A first light receiving section (41) receives the light that has passed through the yarn running space (13), and a second light receiving section (51) receives the light that does not pass through the yarn running space (13). A controller (61) controls a control value for driving the light projecting section (21). The controller (61) identifies a fluctuation factor of the first light receiving section and/or the second light receiving section based on an amount of light received by the first light receiving section (41), an amount of light received by the second light receiving section (51), and the control value for driving. Most Illustrative Drawing: FIG. 1</p> |
