| 摘要 |
<p>The invention relates to an ink level sensing apparatus including ink and having at least one substantially transparent side panel adjacent the ink chamber (20). A fluorescent material is disposed in the ink chamber, the fluorescent material being substantially insoluble in the ink and having a specific gravity which is sufficiently lower than ink to provide an interface between the ink and the fluorescent material. A relatively narrow band light source for emitting panel of the ink cartridge is provided for exciting the fluorescent material. A photosensor for receiving light emitted from a fluorescent material at a second wavelength when the excited fluorescent material (30) crosses the light path is provided, wherein the first and second wavelengths are substantially different. The apparatus provides a means for sensing ink level in an ink cartridge in a reliably relatively inexpensive way.</p> |
