An apparatus for rapidly coupling and decoupling a remote source of ink supply to a disposable ink jet pen filled with a porous ink storage material. This is accomplished without requiring an air-tight seal at the connection of ink into the pen, and is characterized by the use of a capillary tube which extends from the remote source of ink supply to the pen. The capillary tube has a needle mounted at one end thereof for easy penetration into and removal from the porous material within a storage compartment of the pen. The capillary action of the porous material acting on the needle is used draw ink by capillary action from the remote source of ink supply into the pen. This action allows the free liquid surface of the remote ink supply to be positioned below an ink ejection plane of the pen, thereby preventing ink from drooling from the pen during ink jet printing.