Patent ID: 8979227
Filing Date: 2015-03-17
Classification: B41J

Abstract:
1. A method for measuring the volume of printing liquid in a fluid container for an ink jet printer comprising the steps of: i) providing a container for storing and dispensing printing liquid, the container comprising a reservoir with walls enclosing an internal space having a variable volume for storage of the liquid and a port for dispensing the liquid; ii) connecting the port to an inlet of a pump of the printer by a fluid-tight connection; iii) operating the pump to form a withdrawal pressure at the exterior of the port; iv) measuring the minimum withdrawal pressure required to allow dispensing of liquid through the port; and v) determining the volume of liquid from the measured minimum withdrawal pressure, wherein the container is for storing and dispensing ink or solvent for use with a continuous inkjet printer, wherein the reservoir is adapted to support a reduction in pressure of the internal space whereby the equilibrium pressure difference between the internal space and the surrounding atmosphere increased substantially monotonically in magnitude as liquid is dispended; wherein the port is adapted to allow liquid to be dispensed when a withdrawal pressure at the exterior of the port is less than the equilibrium pressure of the internal space; and wherein the port is adapted to prevent air from entering the internal space from outside the reservoir as liquid is dispensed, the container comprising a volume of liquid substantially filling the volume of the internal space.