Fluid end of life sensors

Abstract

In a liquid level monitor for use with a liquid container of a liquid-consuming device, a light source transmits a light beam into the liquid container at a non-normal angle of incidence respective to a wall of the liquid container. A photodetector is positioned in the path of one of (i) the light beam after passing through the liquid container when the light beam is not refracted by liquid in the liquid container and (ii) the light beam after passing through the liquid container when the light beam is refracted by liquid in the liquid container. In another approach, the sensor for detecting empty includes a vibrator and a vibration sensor, and an electronic processor is programmed to determine whether the liquid container is empty of liquid based on the detected vibration of the liquid container.

Dependencies are inferred from the claim text.