Abstract: A method of redirecting ejected ink droplets from a printhead is provided. The method compries the steps of: (a) providing a printhead assembly comprising: a printhead including a plurality of nozzles for ejecting ink droplets onto a print medium, the plurality of nozzles being formed on an ink ejection surface of the printhead; and a nozzle guard positioned over the ink ejection surface, the nozzle guard having a corresponding plurality of channels therethrough, the channels being aligned with the nozzles such that ejected ink droplets pass through respective channels towards the print medium; and (b) ejecting ink droplets from the nozzles. The channels have hydrophobic sidewalls, such that misdirected ink droplets rebound off the sidewalls and continue through the channels towards the print medium.

Abstract: A printhead assembly suitable for redirecting ejected ink droplets is provided. The printhead assembly comprises: a printhead including a plurality of nozzles for ejecting ink droplets onto a print medium, the plurality of nozzles being formed on an ink ejection surface of the printhead; and a nozzle guard positioned over the ink ejection surface, the nozzle guard having a corresponding plurality of channels therethrough, the channels being aligned with the nozzles such that ejected ink droplets pass through respective channels towards the print medium. The channels have hydrophobic sidewalls, such that ejected ink droplets can rebound and be redirected.

Abstract: A thermal inkjet printhead with bubble forming heater elements formed from a material with a nanocrystalline composite structure. Nanocrystalline composite films can be superhard and can facilitate removal of the SiC and Ta anti-cavitation wear coatings. Improved oxidation resistance can also be achieved with some nanocrystalline composites, facilitating removal of the Si3N4 oxidation prevention coating. By removing or reducing the protective coatings, the heater element requires much less energy to form a bubble in the ink. A further benefit is improved crack resistance, which can extend the lifetime of uncoated heaters.

Abstract: An inkjet printhead with a plurality of nozzles, a bubble forming chamber corresponding to each of the nozzles respectively, the bubble forming chambers adapted to contain ejectable liquid, a heater element positioned in each of the bubble forming chambers respectively for heating the ejectable liquid to form a gas bubble that causes the ejection of a drop of the ejectable liquid from the nozzle; and, a print engine controller for controlling the operation of the heater elements; wherein during use, the print engine controller heats the ejectable liquid with the heater element to lower its viscosity prior to a print job; and during printing, the print engine controller ensures that the time interval between successive actuations of each of the heater elements is less than a predetermined time in which the viscosity of the ejectable liquid in the increases to a threshold.

Abstract: A thermal inkjet printhead with generally planar heater elements disposed in respective bubble forming chambers such that they are bonded on one side to the chamber so that the other side faces into the chamber. Each heater element receives an energizing pulse to heat ejectable liquid above its boiling point to form a gas bubble on the side facing into the chamber, whereby the gas bubble causes the ejection of a drop of the ejectable liquid from the nozzle. The chamber has a dielectric layer proximate the side of the heater element bonded to the chamber. The dielectric layer has a thermal product less than 1495 Jm?2K?1s?1/2, the thermal product being (?Ck)1/2, where ? is the density of the layer, C is specific heat of the layer and k is thermal conductivity of the layer. The present invention reduces the drop ejection energy and the heat dissipation into the printhead IC by improving the thermal isolation between the heater and the substrate.

Abstract: The present invention relates to a nozzle for ejecting ink. The nozzle includes an ink chamber in which the ink can be provided and a plurality of elements located adjacent the ink chamber. An actuator is provided for moving the elements into the chamber in a first direction so that ink can be ejected from the ink chamber in a second and opposite direction.

Abstract: A micro-electromechanical actuator includes a pair of elongate layers capable of being heated with an electrical current to thermally expand and to perform work. A pair of spacers separates the elongate layers from each other. The spacers are arranged at respective opposite ends of the elongate layers and are fast with the layers so that the actuator is deflected when one of the layers is heated.

Abstract: A printhead suitable for minimizing cross-contamination between nozzles is provided. The printhead comprises a substrate, which includes a plurality of nozzles for ejecting ink droplets onto a print medium. Each nozzle has a nozzle aperture, which is defined in an ink ejection surface of the substrate. The printhead also comprises a plurality of formations on the ink ejection surface. The surface formations are configured to isolate each nozzle from at least one adjacent nozzle, and typically take the form of enclosures surrounding each nozzle.

Abstract: A method of printing from a printhead, whilst minimizing cross-contamination of ink between adjacent nozzles is provided. The method comprises the steps of: (a) providing a printhead comprising a substrate, which includes a plurality of nozzles for ejecting ink droplets onto a print medium, each nozzle having a nozzle aperture defined in an ink ejection surface of the substrate; the printhead also includes a plurality of formations on the ink ejection surface, the surface formations being configured to isolate each nozzle from at least one adjacent nozzle; and (b) printing onto a print medium using the printhead.

Abstract: A method of fabricating a printhead having isolated nozzles is provided. The method comprises the steps of: (a) providing a substrate, the substrate including a plurality of nozzles for ejecting ink droplets onto a print medium, each nozzle having a nozzle aperture defined in an ink ejection surface of the substrate; (b) depositing a layer of photoresist over the ink ejection surface; (c) defining recesses in the photoresist, each recess revealing a portion of the ink ejection surface surrounding a respective nozzle aperture; (d) depositing a roof material over the photoresist and into the recesses; (e) etching the roof material to define a nozzle enclosure around each nozzle aperture, each nozzle enclosure having an opening defined in a roof and sidewalls extending from the roof to the ink ejection surface; and (f) removing the photoresist.

Abstract: There is disclosed an ink jet printhead which comprises a plurality of nozzles (3) and one or more heater elements (10) corresponding to each nozzle. Each heater element is configured to heat a bubble (12) forming liquid in the printhead to a temperature above its boiling point to form a gas bubble therein. The generation of the bubble causes the ejection of a drop (16) of an ejectable liquid (such as ink) through respective corresponding nozzle, to effect printing. Each heater element is in the form of a beam suspended over at least a portion of the bubble forming liquid so as to be in thermal contact therewith. This configuration of printhead provides for a relatively high efficiency of operation.

Abstract: There is disclosed an inkjet printhead which comprises a plurality of nozzles (3) and one or more heater elements (10) corresponding to each nozzle (3). Each heater element is configured to heat a bubble forming liquid in the printhead to a temperature above its boiling point to form a gas bubble (12) therein. The generation of the bubble causes the ejection of a drop of an ejectable liquid (such as ink) through the respective corresponding nozzle, to effect printing. Each heater element is configured such that an actuation energy of less than 500 nanojoules (nJ) is required to be applied to that element to heat it sufficiently to form such a bubble (12) in the bubble forming liquid (which liquid can also be the ink). This configuration thus provides for a high efficiency printhead.

Abstract: An inkjet printhead (1) which a plurality of nozzles (3) and one or more heater elements (10) corresponding to each nozzle. Each heater is configured to heat a bubble forming liquid in the printhead to a temperature above its boiling. Each heater element has two opposite sides and is suspended within the chamber (7) below the nozzle. The gas bubble is formed at both sides of the heater.

Abstract: A micro-electromechanical actuator assembly includes a substrate that defines a fluid reservoir. An actuator is positioned in the reservoir and has a region of bend material and a heater. The heater is positioned so that heating of the actuator results in differential thermal expansion of the actuator to generate movement and subsequent ejection of ink. The actuator has at least one region of heat conductive material that is positioned to conduct heat from the actuator to facilitate cooling of the actuator.

Abstract: An ink jet printing device includes a substrate that defines a plurality of ink supply passages. Drive circuitry is positioned on the substrate. A plurality of nozzle chamber structures is arranged on the substrate. Each nozzle chamber structure defines a nozzle chamber and an ink ejection port in fluid communication with the nozzle chamber. Each nozzle chamber structure has a wall that incorporates a number of actuators. Each of the actuators is displaceable, on receipt of an electrical signal from the drive circuitry, into and out of the nozzle chamber to eject ink from the ink ejection port.

Abstract: There is disclosed an inkjet printhead integrated which comprises drive circuitry, a plurality of nozzles and one or more heater elements corresponding to each nozzle. Each heater element is configured to heat a bubble forming liquid in the printhead to a temperature above its boiling point to form a gas bubble therein. The generation of the bubble causes the ejection of a drop of an ejectable liquid (such as ink) through respective corresponding nozzle, to effect printing. Each heater element has a surface area to volume ratio greater than 4:1. This configuration ensures that heat is quickly transferred from the elements to the ink for efficient operation and minimal heating of the printhead substrate.

Abstract: A micro-electromechanical fluid ejection device includes a substrate. Drive circuitry is arranged on an outlet side of the substrate. A plurality of nozzle chambers and corresponding fluid inlets is etched into the substrate. A plurality of support structures is positioned on the substrate to cover respective nozzle chambers. Each support structure defines a fluid ejection nozzle in fluid communication with the respective nozzle chamber. A plurality of fluid ejecting members is arranged in respective support structures. The fluid ejecting members are displaceable into and out of the nozzle chambers to eject fluid from respective fluid ejection nozzles. A plurality of actuators is connected to the drive circuitry and to respective fluid ejecting members to displace respective fluid ejecting members into and out of each nozzle chamber on receipt of electrical signals from the drive circuitry to eject ink from each fluid ejection nozzle.

Abstract: A thermal inkjet printhead with heater elements disposed in respective bubble forming chambers for heating part of the ejectable liquid above its boiling point to form a gas bubble that causes the ejection of a drop of the ejectable liquid from the nozzle, wherein, the heater is separated from the nozzle by less than 5 ?m at their closest points; the nozzle length is less than 5 ?m; and the ejectable liquid has a viscosity less than 5 cP. The volume of liquid between the heater and the nozzle determines the inertia of the liquid and its acceleration in response to bubble formation. Moving the heater closer to the nozzle reduces the inertia of the liquid and increases its acceleration, so a lower bubble impulse is needed to eject a drop. This allows the printhead to use smaller heater elements with lower power requirements. Viscous drag in the nozzle reduces the momentum of fluid flowing through the nozzle. The viscous drag increases as the nozzle length (in the direction of fluid flow) increases.

Abstract: An ink jet nozzle arrangement for a printhead is provided. The nozzle arrangement comprises a nozzle chamber for storing ink to be ejected, at least one moveable actuator paddle forming at least a portion of a first wall of said nozzle chamber, and an ink ejection nozzle defined in the first wall. Actuation of the actuator paddle causes ejection of ink from the nozzle.

Abstract: An inkjet printhead chip includes a substrate that defines a plurality of ink supply channels. A drive circuitry layer is positioned in the substrate. A plurality of nozzle arrangements is positioned on the substrate. Each nozzle arrangement includes a nozzle chamber structure arranged on the substrate and defining walls of a nozzle chamber in fluid communication with a respective ink supply channel. A deformable roof structure is arranged on the nozzle chamber structure. The roof structure is deformable on receipt of an actuating signal from the drive circuitry, reciprocally to reduce and enlarge a volume of the nozzle chamber. The roof structure defines an ink ejection port such that, upon such reduction and enlargement, a drop of ink is ejected from the ink ejection port.