Off axis inkjet printing system and method

A printer, comprising:

• a movable carriage;
• a print head assembly (PHA) including
• a PHA body structure mounted in the movable carriage;
• an air-fluid separator structure;
• an air vent region in communication with the separator structure;
• a printhead for ejecting droplets of fluid;
• a fluid plenum in fluid communication with the printhead and the air-fluid separator structure;
• a PHA free fluid reservoir;
• a fluid re-circulation path disposed within said PHA body structure and passing through said separator structure, said plenum and said free fluid reservoir;
• a pump structure supported by said PHA body structure for re-circulating fluid through said re-circulation path during a pump mode;
• a PHA fluid interconnect;
• and
• an fluid supply mounted off the carriage and including a supply reservoir for holding a supply of free fluid and a supply fluid interconnect adapted to connect to said PHA fluid interconnect during a replenishment mode to provide a fluid connection between the supply reservoir and the PHA fluid reservoir when a pressure differential between the PHA and the supply reservoir is sufficient to draw fluid through the fluid interconnect to replenish the fluid in the PHA fluid reservoir.

A fluid delivery system, comprising:

• a print head assembly (PHA) including
• a PHA body structure;
• an air-fluid separator structure within the PHA body structure;
• an air vent region in communication with the separator structure;
• a printhead mounted to the PHA body structure;
• a fluid plenum within the PHA body structure in fluid communication with the printhead and the air-fluid separator structure;
• a PHA free fluid reservoir in the PHA body structure;
• a fluid re-circulation path disposed within said PHA body structure and passing through said separator structure, said plenum and said free fluid reservoir;
• a pump structure supported by said PHA body structure for re-circulating fluid through said re-circulation path;
• and
• an fluid supply for mounting off the carriage and including a supply reservoir for holding a supply of fluid adapted to intermittently connect to said PHA through a fluid connection during a replenishment mode while the pump structure is actuated to draw fluid through the fluid connection to replenish the fluid in the PHA fluid reservoir only when a pressure differential between the PHA and the supply reservoir is sufficient to draw fluid through the fluid connection.

A method for supplying fluid to a print head assembly (PHA), comprising:

• mounting the PHA on a movable carriage of a printing system;
• positioning an fluid supply at a supply location off the carriage including a supply reservoir holding a supply quantity of free fluid;
• bringing the print cartridge and fluid supply into mating contact so that a PHA fluid interconnect is engaged with a supply fluid interconnect to provide a fluid interconnect path;
• pumping fluid through a closed re-circulation path within a PHA housing structure to pump fluid from a PHA free fluid chamber to a PHA capillary structure to a PHA fluid plenum in fluid communication with a PHA printhead and to the free fluid chamber;
• with the capillary structure in a fluid-depleted state, using a dynamic pressure differential between said fluid plenum and said free fluid chamber to draw fluid from the fluid supply reservoir through the fluid interconnect path until the capillary structure reaches a less depleted state.

A method for supplying fluid to a print head assembly (PHA) comprising:

• mounting a PHA including a PHA housing structure, a capillary structure for holding a supply of fluid under negative pressure, a free fluid chamber, a printhead and a fluid plenum in fluidic communication between the capillary structure and the printhead on a movable carriage of a printing system;
• positioning an fluid supply at a supply location off the carriage including a supply reservoir holding a supply quantity of free fluid;
• bringing the print cartridge and fluid supply into mating contact so that a PHA fluid interconnect is engaged with a supply fluid interconnect to provide a fluid interconnect path;
• pumping fluid through a closed re-circulation path within the PHA housing structure to pump fluid from the free fluid chamber to the capillary structure to the plenum and to the free fluid chamber;
• with the capillary structure in a fluid-depleted state, using a dynamic pressure differential between said fluid plenum and said free fluid chamber to draw fluid from the fluid supply reservoir through the fluid interconnect path until the capillary structure reaches a less depleted state.

A fluid delivery system, comprising:

• a multicolor print head assembly (PHA) including
• a PHA body structure for mounting in a movable carriage of a printing system;
• a plurality of PHA units, each assembled in said PHA body structure, each PHA unit comprising:
• an air-fluid separator structure;
• an air vent region in communication with the separator structure;
• a printhead;
• a fluid plenum in fluid communication with the printhead and the air-fluid separator structure;
• a PHA free fluid reservoir;
• a fluid re-circulation path disposed within said PHA body structure and passing through said separator structure, said plenum and said free fluid reservoir;
• a pump structure supported by said PHA body structure for re-circulating fluid through said re-circulation path during a pump mode;
• a PHA fluid interconnect;
• and
• an fluid supply for mounting off the carriage and including for each PHA unit a supply reservoir for holding a supply of free fluid and a supply fluid interconnect adapted to connect to said PHA fluid interconnect during a replenishment mode to provide a fluid connection between the supply reservoir and the PHA fluid reservoir when a pressure differential between the PHA and the supply reservoir is sufficient to draw fluid through the fluid interconnect to replenish the fluid in the PHA fluid reservoir.