Printhead module for expelling ink from nozzles in groups, alternately, starting at outside nozzles of each group

1. A printhead module used in conjunction with a printer controller for supplying fire signals to the printhead module, the printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to the fire signals, such that, for each set of nozzles, a fire signal is provided by the printer controller in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n−1), . . . , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

2. A printhead module according to claim 1 , wherein the nozzle at each given position within the set is fired simultaneously with the nozzles in the other sets at respective corresponding positions.

3. A printhead module according to claim 1 , wherein the printhead module includes a plurality of the rows of nozzles, the printhead module being configured to fire all the nozzles on each row prior to firing any nozzles from a subsequent row.

4. A printhead module according to claim 2 , wherein the rows are disposed in pairs.

5. A printhead module according to claim 3 , wherein the rows in each pair of rows are offset relative to each other.

6. A printhead module according to claim 4 , wherein each pair of rows is configured to print the same color ink.

7. A printhead module according to claim 5 , wherein each pair of rows is connected to a common ink source.

8. A printhead module according to claim 1 , wherein the sets of nozzles are adjacent each other.

9. A printhead module according to claim 1 , wherein the sets of nozzles are separated by an intermediate nozzle, the intermediate nozzle being fired either prior to the nozzle at position 1 in each set, or following the nozzle at position n.

10. A printhead comprising a plurality of printhead modules according to claim 1 .

11. A printhead according to claim 10 , wherein the printhead is a pagewidth printhead.

12. A printhead module according to claim 1 , configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising providing, for each set of nozzles, a fire signal in accordance with the sequence: [nozzle position 1, nozzle position n, nozzle position 2, nozzle position (n−1), . . . , nozzle position x], wherein nozzle position x is at or adjacent the centre of the set of nozzles.

13. A printhead module according to claim 1 , configured to receive dot data to which a method of expelling ink has been applied, the method being applied to a printhead module including at least one row that comprises a plurality of sets of n adjacent nozzles, each of the nozzles being configured to expel ink in response to a fire signal, the method comprising the steps of:

(a) providing a fire signal to nozzles at a first and nth position in each set of nozzles;

(b) providing a fire signal to the next inward pair of nozzles in each set;

(c) in the event n is an even number, repeating step (b) until all of the nozzles in each set has been fired; and

(d) in the event n is an odd number, repeating step (b) until all of the nozzles but a central nozzle in each set have been fired, and then firing the central nozzle.

14. A printhead module according to claim 1 , in communication with a printer controller for controlling a head comprising at least one monolithic printhead module, the at least one printhead module having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth of the printhead, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row, wherein the printer controller is configured to provide one or more control signals that control the order of firing of the nozzles.

15. A printhead module according to claim 1 , wherein each of the nozzles are configured to expel ink in response to a fire signal, such that:

(a) a fire signal is provided to nozzles at a first and nth position in each set of nozzles;

(b) a fire signal is provided to the next inward pair of nozzles in each set;

(c) in the event n is an even number, step (b) is repeated until all of the nozzles in each set has been fired; and

(d) in the event n is an odd number, step (b) is repeated until all of the nozzles but a central nozzle in each set have been fired, and then the central nozzle is fired.

16. A printhead module according to claim 1 , including at least one row that comprises a plurality of adjacent sets of n adjacent nozzles, each of the nozzles being configured to expel the ink in response to a fire signal, the printhead being configured to output ink from nozzles at a first and nth position in each set of nozzles, and then each next inward pair of nozzles in each set, until:

in the event n is an even number, all of the nozzles in each set has been fired; and

in the event n is an odd number, all of the nozzles but a central nozzle in each set have been fired, and then to fire the central nozzle.

17. A printhead module according to claim 1 , having a plurality of rows of nozzles configured to extend, in use, across at least part of a printable pagewidth, the nozzles in each row being grouped into at least first and second fire groups, the printhead module being configured to sequentially fire, for each row, the nozzles of each fire group, such that each nozzle in the sequence from each fire group is fired simultaneously with respective corresponding nozzles in the sequence in the other fire groups, wherein the nozzles are fired row by row such that the nozzles of each row are all fired before the nozzles of each subsequent row.

18. A printhead module according to claim 1 , comprising a plurality of the rows, the printhead module being configured to fire each nozzle in each row simultaneously with the nozzle or nozzles at the same position in the other rows.

19. A printhead module according to claim 1 , including a plurality of pairs of the rows, each pair of rows including an odd row and an even row, the odd and even rows in each pair being offset from each other in both x and y directions relative to an intended direction of print media movement relative to the printhead, the printhead module being configured to cause firing of at least a plurality of the odd rows prior to firing any of the even rows, or vice versa.

20. A printhead module according to claim 19 , wherein all the odd rows are fired before any of the even rows are fired, or vice versa.

21. A printhead module according to claim 19 , wherein all the odd rows, or the even rows, or both, are fired in a predetermined order.

22. A printhead module according to claim 21 , configurable such that the predetermined order is selectable from a plurality of predetermined available orders.

23. A printhead module according to claim 19 , wherein the predetermined order is sequential.

24. A printhead module according to claim 23 , configurable such that the predetermined order can commence at any of a plurality of the rows.