LIQUID CONTAINER WITH PASSIVE CAPACITY STATE SENSING
A liquid container for supplying liquid to a printer, the liquid container having a body having an interior space for containing liquid to a predetermined capacity, a port through the body for delivery of liquid into the body to the predetermined capacity, an aperture through the body at which the interior space of the body is in communication with atmosphere external to the fluid container and a hydrophobic film between the aperture and the interior space of the body, the film being configured so that contact with the liquid being delivered via the port causes a change in the fluid pressure at the port.
1 . A liquid container for supplying liquid to a printer, the liquid container comprising:
a body having an interior space for containing liquid to a predetermined capacity;
a port through the body for delivery of liquid into the body to said predetermined capacity;
an aperture through the body at which the interior space of the body is in communication with atmosphere external to the fluid container; and
a hydrophobic film between the aperture and the interior space of the body, the film being configured so that contact with the liquid being delivered via the port causes a change in the fluid pressure at the port.
2 . A container according to claim 1 , wherein a material of the hydrophobic film is expanded polytetrafluoroethylene.
3 . A container according to claim 1 , wherein the aperture comprises a tortuous path to liquid.
4 . A container according to claim 3 , wherein the tortuous path is a serpentine channel formed through the body.
5 . A container according to claim 3 , wherein the tortuous path has a gas vent on an exterior surface of the body, the gas vent being covered by a piercable air impervious film.
6 . A container according to claim 1 , wherein the port and aperture are located through an upper surface of the body so that the liquid being delivered into the interior space of the body fills said interior space from a lower surface of the body to said upper surface.