Patent ID: 7040728
Filing Date: 2006-05-09
Classification: B41J

Abstract:
1. A sensor target usable to determine a level of a liquid in a fluid reservoir having a top surface and a bottom surface, the sensor target comprising: a low prism extending in the fluid reservoir from a transmission surface on at least one of the top surface and the bottom surface to a low position from the bottom surface, the low prism having a low incident surface and a low reflecting surface; and a high prism extending in the fluid reservoir from the transmission surface on the one of the top and bottom surfaces to a high position from the bottom surface, the high prism having a high incident surface and a high reflecting surface, wherein: light is projected from a single source through the transmission surface into the low prism to the low incident surface and the high prism to the high incident surface, the light is reflected from the low reflecting surface of the low prism through the transmission surface when the level of the fluid is below the low prism, the light is reflected from the high reflecting surface of the high prism through the transmission surface when the level of the fluid is below the high prism, and the light is projected through the low and high prisms at separate time intervals.