Printhead integrated circuit for a pagewidth inkjet printhead
View Patent ↗A printhead integrated circuit for a pagewidth printhead includes an elongate substrate that defines a plurality of ink inlet passages. A drive circuitry layer is positioned on the substrate. A plurality of nozzle chamber structures is positioned on the substrate and defines nozzle chambers in fluid communication with respective ink inlet passages and ink ejection ports in fluid communication with respective nozzle chambers. A plurality of ink ejection members is received in respective nozzle chambers. The ink ejection members are reciprocally displaceable to eject ink from the ink ejection ports. Elongate actuators are each fast at a fixed end with the substrate and are attached to respective ink ejection members at a free end. The actuators are connected to the drive circuitry layer to displace respective ink ejection members on receipt of electrical pulses from the drive circuitry layer. The nozzle chamber structures and associated elongate actuators are positioned on the substrate to define at least one pair of longitudinally extending rows of nozzle chamber structures adjacent each other.
1. A printhead integrated circuit for a pagewidth printhead, the printhead integrated circuit comprising
an elongate substrate that defines a plurality of ink inlet passages;
a drive circuitry layer positioned on the substrate;
a plurality of nozzle chamber structures positioned on the substrate and defining nozzle chambers in fluid communication with respective ink inlet passages and ink ejection ports in fluid communication with respective nozzle chambers;
a plurality of ink ejection members received in respective nozzle chambers and reciprocally displaceable to eject ink from the ink ejection ports; and
a plurality of elongate actuators, each fast at a fixed end with the substrate and attached to respective ink ejection members at a free end, the actuators being connected to the drive circuitry layer to displace respective ink ejection members on receipt of electrical pulses from the drive circuitry layer, wherein
the nozzle chamber structures and associated elongate actuators are positioned on the substrate to define at least one pair of longitudinally extending rows of nozzle chamber structures adjacent each other.
2. A printhead integrated circuit as claimed in claim 1 , in which the nozzle chamber structures and associated elongate actuators are positioned on the substrate with at least two pairs of longitudinally extending rows of nozzle chamber structures, the elongate actuators of one of the rows of one pair interleaved with the elongate actuators of one of the rows of an adjacent pair.
3. A printhead integrated circuit as claimed in claim 2 , in which the elongate actuators are oriented at an angle with respect to an axis orthogonal to a longitudinal axis of the substrate.
4. A printhead integrated circuit as claimed in claim 2 , in which each actuator is a thermal actuator that includes a heater element formed in a structural material and connected to the drive circuitry layer to generate differential thermal expansion and contraction so that the actuator is deflected, thereby displacing the ink ejection member.
5. A printhead integrated circuit as claimed in claim 4 , in which the drive circuitry layer incorporates drive transistors for each elongate actuator, the drive transistors each including a series of traces interposed between respective actuators and the substrate, the traces extending substantially orthogonally to longitudinal axes of the respective actuators and each heater element defining a series of corrugations that correspond with the traces associated with that heater element.
6. A printhead integrated circuit as claimed in claim 5 , in which a cross-sectional area of each heater element is reduced at a distal region with respect to the nozzle chamber structure to amplify a heating effect of a current passing through the heater element.