Patent ID: 8727467

Claim:
A liquid consumption device comprising: a liquid container configured to supply liquid to the liquid consumption device; a prism provided to the liquid container, and configured to receive light that is made incident from outside and to emit the incident light again toward the outside according to a liquid residual state inside the liquid container; a light emitting unit configured to radiate the light to the prism; a light receiving unit configured to receive the light emitted from the prism; and a control unit configured to control the light emitting unit to radiate the light, and to determine the liquid residual state based on a light volume of the light received by the light receiving unit, wherein, before the liquid residual state is determined, the control unit is configured to determine a threshold value of the liquid container that is used for determining the liquid residual state, and/or is configured to determine a light radiation volume by the light emitting unit, based on a light volume of reflected light that is reflected by an outer surface of the prism and received by the light receiving unit upon radiation of the light by the light emitting unit.