Ink containment system and ink level sensing system for an inkjet cartridge

An inkjet cartridge and ink level sensing system, comprising:

• a cartridge housing within which a collapsible ink reservoir is disposed;
• a flexible membrane affixed to an internal surface of the housing and to a rigid moveable plate forming the ink reservoir;
• wherein the flexible membrane has an annular configuration having a first peripheral edge affixed adjacent to the internal surface of the housing and a second peripheral edge affixed to the moveable plate;
• a spring biasing mechanism disposed between the moveable plate and the inner surface of the housing for biasing the plate away from the housing surface generating a negative pressure in the ink reservoir and the housing surface remains stationary relative to movement of the moveable plate;
• an aperture in a side of the housing aligned with a portion of the moveable plate not covered by the flexible membrane;
• wherein the ink level sensing system comprises a light source that transmits light through the aperture that is reflected off of the portion of the moveable plate not covered by the flexible membrane and through the aperture or another aperture on the same side of the housing;
• a position sensing device that detects the light reflected off the moveable plate and transmits a signal indicative of the position of the plate in the cartridge, which represents a volume of ink remaining in the ink reservoir.