Induktive Tintenpegelerfassungsvorrichtung für Tintenvorräte

摘要

An ink level detection mechanism 14 comprises a flexible ink container 16, e.g. in the form of a collapsible bag contained within a cartridge (10, Fig. 1), for storing an ink supply used by an inkjet pen. The ink container has opposing sides which move relative to one another depending upon an amount of ink held therein and which carry a pair of electrically conductive coils 30, 32 formed on the opposing sides of the container. The coils 30, 32 move relative to one another in conjunction with the movement of the container sides, and an ink level sensing circuit 50 connected to the coils generates a signal which induces a magnetic field between the pair of coils. The circuit 50 senses the level of ink within the container 16 by detecting change in the field as the coils 30, 32 are moved relative to one another. The field strength increases as the coils 30, 32 are moved closer together, thereby improving the quality of the measurement as the ink is used from the container.