Air purge system for an ink-jet printer

A method of priming an inkjet pen with ink, comprising the steps of:

• providing an ink jet pen body having a containment chamber for holding ink, and printhead orifices in free fluid communication with the containment chamber;
• providing a supply of ink remote from and not carried by the ink jet pen body;
• providing a supply line between the containment chamber and supply of ink through which supply line ink is hydraulically drawn from the supply of ink during printing as ink is expelled from the printhead orifices;
• introducing the ink under positive pressure from the remote supply of ink into the ink supply line and containment chamber to flush air from the supply line and containment chamber prior to beginning printing;
• and
• in response to a preselected signal introducing the ink under positive pressure into the supply line and the containment chamber to remove air that enters the supply line and the containment chamber.

An ink jet printer, comprising:

• a chassis;
• a docking bay having a pump actuator and a fluid inlet coupled to a supply line;
• an ink jet pen comprising an ink containment chamber with a printhead having an orifice coupled with a droplet generator for expelling droplets of ink through the orifice, and the orifice communicates with a firing chamber that in turn communicates with the containment chamber through a capillary supply line;
• a reservoir coupled to the chassis for containing a quantity of ink;
• a flexible supply line between the reservoir and containment chamber that establishes an uninterrupted fluid pathway from a supply of ink to the firing chamber, such that ink is drawn into the firing chamber by capillary action as the droplets of ink are expelled through the orifice, which in turn draws ink into the containment chamber from the supply line without passing through a pressure regulator;
• further wherein the reservoir is at a sufficiently lower elevation than the firing chamber to establish through the supply line a negative pressure on ink in the containment chamber relative to ink in the reservoir to inhibit drooling of ink out of the orifice when the reservoir, supply line and containment chamber contain ink;
• a fluid outlet from the reservoir that couples with the fluid inlet in the chassis and establishes a fluid connection therewith when the ink supply is in a docked position, and the supply line communicates with the reservoir through the fluid outlet;
• a variable volume pump carried on the chassis, wherein the pump has a pump chamber in fluid communication with the reservoir and fluid outlet, and the pump chamber communicates with the reservoir through a one-way valve that allows ink to flow only from the reservoir to the pump chamber;
• and
• a supply line occluder that is activated when the ink jet printer is inactive to occlude the supply line and inhibit drooling of ink from the orifice:
• wherein the pump is actuatable by the actuator when the ink supply is in the docked position to enlarge a pump chamber volume and to draw ink from the reservoir through the one-way valve, then subsequently to supply the ink under positive pressure through the fluid outlet to the supply line and containment chamber by reducing the pump chamber volume.

A method of priming an ink jet pen with ink, comprising the steps of:

• providing an ink jet pen body having a containment chamber for holding ink, and printhead orifices in free fluid communication with the containment chamber;
• providing a supply of ink remote from and not carried by the ink jet pen body;
• providing a supply line between the containment chamber and supply of ink, through which supply line ink is hydraulically drawn from the supply of ink during printing as ink is expelled from the printhead orifices;
• introducing the ink under positive pressure from the remote supply of ink into the ink supply line and containment chamber to flush air from the supply line and containment chamber prior to beginning printing;
• the step of maintaining a back pressure from the supply of ink to the containment chamber, with a relatively negative pressure at the supply of ink, to prevent drooling of ink from the printhead orifice;
• and
• the step of maintaining the back pressure at the supply of ink including using the pump to maintain a negative pressure on the ink in the supply line and containment chamber relative to the ink in the supply of ink.

A method of supplying ink for an ink jet printer having a docking station with a pump actuator and a fluid inlet coupled to a supply line for providing the ink to a movable printhead, the method comprising the steps of:

• providing a replaceable ink supply comprising a chassis, a reservoir containing a quantity of ink coupled to the chassis, a fluid outlet carried on the chassis, a pump carried on the chassis and having a variable volume chamber, a pump inlet in fluid communication with the reservoir and the variable volume chamber, and a pump outlet in fluid communication with the variable volume chamber and fluid outlet, and a valve positioned in the pump inlet for allowing a flow of ink into the variable volume chamber and limiting the flow of ink from the variable volume chamber to the reservoir;
• providing an ink jet pen comprising an ink containment chamber in direct fluid communication, through the supply line, with the fluid outlet, wherein a printhead of the ink jet pen has a plurality of orifices, with associated firing chambers in fluid communication through capillary supply lines with the ink containment chamber, wherein ink is drawn into the firing chambers by capillary action from the ink containment chamber as ink is expelled in droplets through the printhead orifice;
• providing a purge valve that vents air from the ink containment chamber;
• inserting a replaceable ink supply into a docking position within the docking station with the fluid outlet of the chassis in fluid communication with the pump outlet;
• expanding the variable volume chamber of the pump to draw the ink from the reservoir into the pump;
• then reducing the volume of the variable volume chamber to expel the ink from the pump into the fluid outlet and the supply line, until the ink containment chamber is filled with the ink, and all air in the supply line and the ink containment chamber is vented out of the check valve;
• and
• expelling droplets of ink from the firing chambers of the printhead to reduce the volume of ink in the ink containment chamber, which draws the ink into the firing chamber by capillary action, which in turn draws the ink into the containment chamber through an uninterrupted contiguous liquid line of ink from the ink supply to the supply line into the containment chamber and firing chamber.