AN INK CONTAINMENT SYSTEM AND INK LEVEL SENSING SYSTEM FOR AN INKJET CARTRIDGE
An ink containment system for an inkjet cartridge, for storing ink for printing, comprises a rigid basin member and a rigid moveable plate. A flexible membrane is affixed to a surface of the basin member and to a surface of the plate forming an ink reservoir within the basin member, plate and flexible membrane. A spring-biased mechanism is disposed between the basin member and plate, for biasing the plate apart from the basin member, generating a negative pressure within the ink reservoir and the basin member remaining stationary relative to the movement of the plate. The basin member has a bowl-like configuration and the spring is seated within the reservoir in such a way that when the ink reservoir has collapsed due to depletion of ink, the flexible membrane and moveable plate are substantially flush with surfaces of the basin member. The cartridge may also include an ink level sensing system that utilizes an optical sensing system to detect movement or position of the moveable plate to determine a remaining ink volume. In addition, the cartridge includes a standpipe that places the ink reservoir in fluid communication with printhead and has a longitudinal axis that is disposed at an acute angle relative to the printhead, so that gas bubbles at the printhead may travel toward the reservoir in a horizontal or vertical printing position.