| 摘要 |
<p>An adjustable optical ribbon edge sensor (40) having a relatively short throat (60) for ease of loading a towel ribbon (22) in a high-speed line printer (10) includes one or more pairs of photosensitive switches (66), coupled through a variable resistor (74), to a comparator (76) facilitates accurate and repeated detection of the ribbon (22) edge regardless of the color of the ribbon (22). By adjusting the variable resistor (74), the comparator (76) is biased for the particular color ribbon (22) in use.</p> |
