PRINTING SYSTEM WITH DATUM FEATURES ON PRINTHEAD CARRIAGE

1 . A printing system comprising:

a print zone;

a media path extending through the print zone along a paper axis;

a printhead carriage for mounting a plurality of printhead modules adjacent the print zone such that the printhead modules collectively span the media path and are staggered with respect to the paper axis, the printhead modules each having nozzles arranged in parallel rows; and,

a plurality of datum features for holding the printhead carriage such that the parallel rows extend normal to the paper feed axis.

2 . The printing system according to claim 1 wherein the printhead carriage has a floor section for supporting the printhead modules and the datum features are secured to the floor section.

3 . The printing system according to claim 2 wherein the printheads modules are staggered with respect to the paper feed axis as well as a direction transverse to the paper feed axis to span the media path.

4 . The printing system according to claim 3 wherein each of the printhead modules has a series of elongate printhead integrated circuits positioned end to end and extending parallel to the direction transverse to the paper axis.

5 . The printing system according to claim 3 wherein the printhead cartridge has three of the datum features, two of the datum features being positioned to one side of the printhead modules and the remaining datum feature being positioned on the opposing side of the printhead modules with respect to the direction transverse to the paper axis.

6 . The printing system according to claim 5 further comprising three datum points for engaging the datum features, two of the datum points are positioned on one side of the media path and the remaining datum point positioned on the opposite side of the media path.

7 . The printing system according to claim 1 further comprising:

an ink supply;

a feed line coupled to the ink supply;

a return line coupled to the ink supply; wherein,

the printhead modules are each fluidically coupled to the feed and the return lines;

a bypass line coupling the feed line to the return line; and,

a pumping system configured to initially prime ink through the feed line, the return line, and the bypass line before priming each of the printhead modules.

8 . The printing system according to claim 7 further comprises a feed valve for closing fluid communication between the feed line and the ink supply as well as the return line and the ink supply.

9 . The printing system according to claim 8 further comprises a bypass valve in the bypass line.

10 . The printing system according to claim 9 wherein the feed line, the return line, and the bypass line form a closed loop when the feed valve is closed and the bypass valve is open.

10 . The printing system according to claim 1 wherein during use the pumping system is configured to purge bubbles from any of the printheads through the return line.

11 . The printing system according to claim 10 further comprising a plurality of accumulator reservoirs, one of the accumulator reservoirs being connected to each of the printhead modules respectively, wherein during use, the accumulator reservoirs receive air from the respective printhead modules during a priming operation.

12 . The printing system according to claim 11 further comprising valves coupling each of the accumulator reservoirs to the ink supply, each of the valves being configured to open when the ink level in the accumulator reservoir reaches a lower limit of a predetermined ink level range, and close when the ink level in the accumulator reservoir reaches an upper limit of the ink level range, wherein each of the printheads has nozzles for ejecting ink onto media and the accumulator reservoir is fixed relative to the printheads such that hydrostatic ink pressure at the nozzles is generated by the elevation of the ink level in the accumulator reservoir relative to the elevation of the of the nozzles.

13 . The printing system according to claim 12 wherein the valves are float valves with a float that is buoyant on the ink in the accumulator reservoir to open the valve when the ink level reaches the lower limit and close the valve as the ink level approaches the upper limit.

14 . The printing system according to claim 13 wherein the feed line and the return line are coupled to each of the accumulator reservoirs via separate couplings.

15 . The printing system according to claim 1 further comprising:

a drive roller for feeding different sizes of media along a media path; and,

an ink aerosol collection system for removing ink aerosol from areas adjacent the media path; wherein,

the ink aerosol collection system is configured to remove aerosol at a greater rate in response to an increase in the media size.

16 . The printing system according to claim 15 wherein the printheads are positioned on a first side of the media path and the aerosol collection system has a first aerosol collection opening positioned on the first side of the media path and a second aerosol collection opening positioned on a second side of the media path.

17 . The printing system according to claim 16 wherein the media path has a width corresponding to a maximum width of media that can be printed by the printing system and the aerosol collection system is configured to collect ink aerosol from the first and second aerosol collection openings when the media being printed is less than the maximum width.

18 . The printing system according to claim 17 further comprising:

a platen for supporting the media during printing; wherein,

the platen has a spittoon system for collecting non-printing drops of ink ejected from the printheads.

19 . The printing system according to claim 17 further comprising a plurality of service modules, one of the service modules corresponding to each of the printheads respectively, the service modules being configured to operate in a spittoon mode to provide the spittoon system.

20 . The printing system according to claim 17 wherein any of the printheads not fully required to print media that is less than the maximum width, have the corresponding service module operating in the spittoon mode.