| 摘要 |
<p>PURPOSE:To provide a means which enables the presence of ink in an ink tank in an ink jet printer or the like to be detected by only one ink detecting device even when a plurality of colors are present and which enables the ink to be correctly detected at low cost without affecting the ink. CONSTITUTION:A prism portion 2 is formed integrally with a transparent ink tank 1, and light is made to impinge on the prism portion 2 from a light source 4 at an angle somewhere between two critical angles, i.e., the critical angle of total reflection as determined by the refractive index of the ink tank member 1 and the critical angle of total reflection as determined by the air refractive index of the tank member 1, and the reflected light is detected by a sensor 5 so as to detect whether or not ink 3 is in the tank 1.</p> |
