Abstract: An ink pen is provided with a hydrophobic membrane to control the leakage of ink. The ink pen has a vent, such as a bubble generator, to allow the ingress of air into the ink reservoir and thereby regulate the backpressure within the reservoir. The hydrophobic membrane which allows the flow of air but prevents the flow of ink is positioned within the vent to control leakage of ink from the ink pen through the vent.

Abstract: The ink-jet print cartridge, which has an internal accumulator for maintaining appropriate back pressure within the pen reservoir, and a bubble generator for providing additional regulation, is refilled by a process that provides for the reestablishment of the necessary back pressure upon refilling and that prevents leakage arising as a result of the refilling operation.

Abstract: The back pressure of an ink pen is maintained by providing a capillary member adjacent a bubble generator. Regardless of the orientation of the pen, the capillary member maintains a quantity of ink adjacent an orifice defined by the bubble generator. The quantity of ink serves to supply a liquid seal formed in the orifice. As the back pressure within the ink pen rises to its maximum level, the liquid seal within the orifice is overcome and ambient air bubbles into the reservoir to lower the back pressure. As the back pressure returns to a desirable point, ink trapped by the capillary member enters the orifice to reseal the orifice.

Abstract: The accumulator regulates changes in the back pressure of an ink-jet pen reservoir so that ink does not leak from the pen print head and so that the print head is able to completely empty the reservoir of ink. The accumulator includes a flexible bag that is mounted to a flat curved spring. The elasticity of the spring tends to contract the bag as the bag expands in response to back pressure reduction in the reservoir.

Abstract: The accumulator regulates changes in the back pressure of an ink-jet pen reservoir so that ink does not leak from the pen print head and so that the print head is able to completely empty the reservoir of ink. The accumulator includes a flexible bag that is mounted to a flat curved spring. The elasticity of the spring tends to contract the bag as the bag expands in response to back pressure reduction in the reservoir.

Abstract: The valve is operable with a bubble generator that provides a restricted flow of air bubbles into a reservoir of an ink-jet pen to relieve excessive back pressure in the pen. The valve includes housed operating liquid that closes the valve in the event that the pen is tipped out of an upright orientation. A hydrophobic air-porous vent is provided for permitting passage of air bubbles through the valve into the reservoir while prohibiting the flow of the operating liquid through the vent.