Ink distribution structure for a printhead

1. A laminated ink distribution structure for an inkjet printhead, the printhead having an ink supply molding for supplying a plurality of different colored inks to the laminated ink distribution structure, and printhead integrated circuit (IC) with an array of ink ejection nozzles for ejecting ink supplied by the laminated ink distribution molding, the laminated ink distribution structure comprising:

a plurality of layers in the form of elongate strips each having an array of ink feed apertures formed therethrough, such that each aperture in one of the layers connects with at least one aperture in an adjacent layer to establish separate fluid paths from the ink supply molding to the printhead IC for each of the different colored inks, the layers having an outermost layer defining ink inlets for connection to the supply molding and another outermost layer defining ink outlets for connection to the printhead IC, the ink inlets defining an elongate rectangular array and the ink outlets defining a comparatively narrow rectangular array aligned with a longitudinal centre line of the rectangular array of the ink inlets; and,

in at least one of the layers, at least some of the apertures have openings in one side of the layer of a different size to their corresponding openings in the other side of the layer.

2. A laminated ink distribution structure according to claim 1 wherein the openings in said one side of the layer are holes and their corresponding openings in the other side of the layer are channels.

3. A laminated ink distribution structure according to claim 1 wherein all the layers have at least some of the apertures with openings in one side of the layer that have a different size to the corresponding openings in the other side of the layer.

4. A laminated ink distribution structure according to claim 1 wherein the ink inlets are arranged in longitudinal rows of holes on both sides of the longitudinal centre line, the holes in the rows closest the mid-line correspond to channels in the other side of the outermost layer, the holes in the rows second closest to the longitudinal centre line are in fluid communication with channels in the layer adjacent the outermost layer, and so on with each pair of rows successively farther from the centre line being in communication with channels in successive layers, such that the channels direct ink towards the longitudinal centre line where corresponding rows of smaller holes feed ink to the array of ink outlets.

5. A laminated ink distribution structure according to claim 4 wherein the ink supply molding has a series of elongate channels for holding the different colored inks respectively, the outermost layer of the laminate structure sealing the open top of each channel to avoid ink leakage.

6. A laminated ink distribution structure according to claim 1 wherein one of the layers is a tape automated bond (TAB) film for connecting power and control signals to the printhead IC.

7. A laminated ink distribution structure according to claim 6 wherein the structure includes ducts for directing a flow of air to the printhead IC to purge particulate contaminants that could potentially clog the nozzles.

8. A laminated ink distribution structure according to claim 1 wherein the structure supports a series of printhead ICs in overlapping relationship.

9. A laminated ink distribution structure according to claim 8 wherein one of the layers has slots receiving the printhead ICs.

10. A laminated ink distribution structure according to claim 1 wherein at least some of the layers of the structure are precision micro-moldings of Acetal type material.