A fluid delivery system for use with ink jet printers, the system comprising: a) a chamber housing a fluid suitable for ink jet printing; b) a conduit comprising a distal end fluidly connected to the chamber and a proximal end configured for fluid connection to an ink jet cartridge for delivering the fluid to an inkjet printer; and characterized by c) a magnetic valve assembly positioned inline between the opposing ends of the conduit, to regulate flow of the fluid to the proximal end, wherein the magnetic valve assembly comprises: i) a hollow body; ii) a collar positioned within the body; iii) a flap configured to engage the collar by a force of magnetic attraction (Fm), wherein the engagement is suitable for closing the flap to prevent passage of fluid through the body and disengagement is suitable for opening the flap to permit passage of the fluid through the body, further wherein the force of magnetic attraction (Fm) is configured to be greater than a force of positive pressure (Fp) applied by the fluid from the chamber and less than a combined force of the force of positive pressure (Fp) and an applied force of negative pressure (Fn) through the proximal end of the conduit thereby biasing the flap closed prior to applying the force of negative pressure; and iv) a float configured to move proximally when applying the force of negative pressure (Fn) to permit the flap to open and configured to float distally against the flap when the force of negative pressure (Fn) is released to reposition the flap next to the collar to induce magnetic attraction with the collar thereby closing the flap. a) a chamber housing a fluid suitable for ink jet printing; b) a conduit comprising a distal end fluidly connected to the chamber and a proximal end configured for fluid connection to an ink jet cartridge for delivering the fluid to an inkjet printer; and characterized by c) a magnetic valve assembly positioned inline between the opposing ends of the conduit, to regulate flow of the fluid to the proximal end, wherein the magnetic valve assembly comprises: i) a hollow body; ii) a collar positioned within the body; iii) a flap configured to engage the collar by a force of magnetic attraction (Fm), wherein the engagement is suitable for closing the flap to prevent passage of fluid through the body and disengagement is suitable for opening the flap to permit passage of the fluid through the body, further wherein the force of magnetic attraction (Fm) is configured to be greater than a force of positive pressure (Fp) applied by the fluid from the chamber and less than a combined force of the force of positive pressure (Fp) and an applied force of negative pressure (Fn) through the proximal end of the conduit thereby biasing the flap closed prior to applying the force of negative pressure; and iv) a float configured to move proximally when applying the force of negative pressure (Fn) to permit the flap to open and configured to float distally against the flap when the force of negative pressure (Fn) is released to reposition the flap next to the collar to induce magnetic attraction with the collar thereby closing the flap. i) a hollow body; ii) a collar positioned within the body; iii) a flap configured to engage the collar by a force of magnetic attraction (Fm), wherein the engagement is suitable for closing the flap to prevent passage of fluid through the body and disengagement is suitable for opening the flap to permit passage of the fluid through the body, further wherein the force of magnetic attraction (Fm) is configured to be greater than a force of positive pressure (Fp) applied by the fluid from the chamber and less than a combined force of the force of positive pressure (Fp) and an applied force of negative pressure (Fn) through the proximal end of the conduit thereby biasing the flap closed prior to applying the force of negative pressure; and iv) a float configured to move proximally when applying the force of negative pressure (Fn) to permit the flap to open and configured to float distally against the flap when the force of negative pressure (Fn) is released to reposition the flap next to the collar to induce magnetic attraction with the collar thereby closing the flap.