| 摘要 |
<p>A powder level indicator free from malfunction due to deposition of powder, which indicates a level (capacity) of powder steplessly by using only one sensor. The indicator is disposed inside a powder tank. It includes an ultrasonic sensor attached to an upper cover in such a manner as to face downward inside the powder tank, and a protective pipe provided at the distal end of the ultrasonic sensor. The protective pipe comprises a metallic protective pipe whose inner surface is mirror-finished. The lower end portion of the inner surface of this protective pipe is smoothly rounded.</p> |
