Abstract: An ink jet printhead nozzle arrangement includes a wafer substrate that defines side walls and an inlet opening of an ink chamber. Drive circuitry is arranged on the wafer substrate. A roof wall assembly defines a roof of the ink chamber and an ink ejection port in fluid communication with the ink chamber. The roof wall assembly includes a nozzle rim supported in general alignment with the inlet opening. A series of radially positioned actuators are each connected to the substrate to receive electrical drive signals, with free ends of the actuators terminating proximate the nozzle rim. The actuators are configured so that, on receipt of an electrical signal from the drive circuitry, said free ends of the actuators are displaced into the ink chamber to reduce a volume of the ink chamber and to eject ink from the ink ejection port.

Abstract: An ink jet printhead with a plurality of nozzles that each nozzle defining a planar nozzle aperture. A bubble forming chamber corresponds to each of the nozzles and a heater is positioned in each of the chambers respectively. The heater has a planar structure with a heater element extending between two electrodes, so that it is suspended by the electrodes in the bubble forming chamber for thermal contact with a printing fluid. The heater element is suspended so that the plane of the heater is parallel to the planar nozzle aperture.

Abstract: A thermoelastic device comprising an expansive element is disclosed. The expansive element is formed from a material, which is preselected by calculating a dimensionless constant for the material. The dimensionless constant is indicative of the potential effectiveness of the material in a particular application, such as a micro-electromechanical system.

Abstract: A method is provided for manufacturing an inkjet nozzle. The method includes the step of depositing a plastics material layer on a substrate incorporating heater actuator circuitry. The plastics material layer is etched to form a nozzle rim defining an ink port through which ink can be ejected and a plurality of elongate actuator arms extending radially with respect to the nozzle rim. A tapered ink chamber may be etched in the nozzle body so that the ink port and ink chamber are in fluid communication with each other.

Abstract: A method of fabricating a printhead integrated circuit includes the step of forming a first layer of a polymeric material on a substrate that incorporates drive circuitry. A heater element is formed on the first layer of polymeric material to be connected to the drive circuitry. A second layer of a polymeric material is formed on the heater element and the first layer such that the heater element is embedded in polymeric material. The polymeric layers are etched to define a plurality of radially extending bridging portions which terminate in a nozzle rim and a plurality of actuators which each extend between a respective pair of adjacent bridging portions and each terminate in a free end proximal to the rim. The substrate is etched so that the substrate and the actuators define a nozzle chamber in fluid communication with an ink ejection port defined by the nozzle rim.

Abstract: A method for manufacturing a micro-electromechanical printer nozzle arrangement on a substrate having a layer of integrated drive circuitry includes etching a nozzle region through the layer of integrated drive circuitry up to the substrate. Electrical contact regions are etched about the nozzle region. Metal and polytetrafluoroethylene (PTFE) layers are deposited and etched on the layer of integrated drive circuitry so that the metal layer defmes heater elements in electrical contact with the drive circuitry and embedded in PTFE structures disposed about the nozzle region. A nozzle chamber is etched in the substrate such that the nozzle chamber is in fluid communication with the nozzle region. The substrate is back-etched to define an ink channel in fluid communication with the nozzle chamber.

Abstract: A method suitable for etching hydrophilic trenches into a substrate, such as silicon, is provided. The method comprises etching and sidewall passivation processes for achieving anisotropy. Sidewalls of the etched trench are made hydrophilic during the etch by virtue of a hydrophilizing dopant in a passivating gas plasma. The method is useful for etching ink supply channels in inkjet printheads.

Abstract: A thermal inkjet printhead with heater elements disposed in respective bubble forming chambers for heating a water-based printing fluid to form a gas bubble for ejecting a drop of the printing fluid from the nozzle. The heater is separated from the nozzle by less than 5 ?m at their closest points and the nozzle length is less than 5 ?m. 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. By reducing the nozzle length, a lower bubble impulse is needed to eject a drop.

Abstract: A method is provided for manufacturing a printer nozzle. The method includes the step of depositing a metal layer upon a semi-conductor wafer. The metal layer defines a pair of protruding portions which each form a respective electrical contact. The method further includes the step of etching the metal layer through to the wafer to form a nozzle region and to electrically isolate the electrical contacts. In one embodiment, the nozzle region is defined by a circular wall.

Abstract: An inkjet printhead that has a plurality of nozzles and respective heater elements, together with drive circuitry that can send a pulse of electrical energy to each heater element to form a vapor bubble in the printing fluid that ejects a drop of printing fluid through the nozzle. The pulse of electrical energy is less than 200 nanoJoules so that the power consumption of the printhead is low. This configuration provides for very efficient operation.

Abstract: A nozzle arrangement includes a wafer defining a nozzle chamber which can be supplied with ink via an ink supply channel. A cover is provided which covers the nozzle chamber. The cover defines a plurality of radially extending bridging portions which terminate in a common rim through which ink in the chamber can be ejected. The cover further defines a plurality of thermal bend actuators which each extend between a respective pair of adjacent bridging portions and each terminate in a free end proximal to the rim. Each thermal bend actuator is configured to bend upon actuation so that its free end enters the nozzle chamber and ejects ink through the rim.

Abstract: A nozzle arrangement for an inkjet printhead, the nozzle arrangement including a substrate that incorporates drive circuitry and defines an ink chamber and an ink supply channel in fluid communication with the ink channel. A cover is fast with the substrate to cover the ink chamber. The cover defines an ink ejection port bounded by a nozzle rim through which ink can be ejected. The cover includes a plurality of actuators extending radially with respect to the rim. Each actuator has a free end located proximal to the rim, each actuator being configured so that, on receipt of a drive signal from the drive circuitry layer, its free end can move into the ink chamber to reduce a volume of the ink chamber and thereby eject ink within the ink chamber from the ink ejection port.

Abstract: An inkjet nozzle includes a substrate defining an ink chamber. A cover is mounted to the substrate and covers the ink chamber. The cover comprises a rim through which ink can be ejected. A plurality of fixed support arms supports the rim. A plurality of movable actuator arms are each located between an adjacent pair of fixed support arms. The actuator arms can move into the chamber to eject ink from the rim. The actuator arms extend radially outwardly from the rim and collectively have rotational symmetry.

Abstract: A thermoelastic actuator to be arranged in an inkjet printer comprises an active heater layer and at least one passive thermal conductor layer. A thermal insulator is located between the heater layer and said at least one thermal conductor layer. The at least one thermal conductor layer is also embedded in the thermal insulator.

Abstract: An inkjet printhead is provided comprising a substrate defining chambers for storing ink, with each chamber having an ink ejection port and actuators arranged to bend upon actuation to displace the port thereby ejecting ink therefrom. Each actuator incorporates a conductive resistive heating element encased within a material having a high coefficient of thermal expansion. Each heating element is configured to cause uneven expansion of the encasing material upon heating so that the actuator bends in a predetermined direction.

Abstract: A fluid sensor for detecting fluid in a chamber, has a MEMS sensing element of conductive material with a resistance that is a function of temperature, and electrical contacts for connection to an electrical power source for heating the sensing element with an electrical signal, so that control circuitry can measure the current passing through the sensing element during heating of the sensing element; and determine the temperature of the sensing element from the known applied voltage, the measured current and the known relationship between the current, resistance and temperature. As the temperature of the element will be greater if it is in the presence of gas rather than liquid, the sensor determines if there is liquid or gas in the chamber. This is particularly useful to detect if the chambers of an inkjet printhead are primed with ink.

Abstract: A method of fabricating an inkjet printhead IC is provided which includes etching a circuitry layer to define first regions, depositing thermally expandable material thereover, etching the thermally expandable material and circuitry layer to define second regions having via holes, forming heaters at the second regions electrically contacting the circuitry layer through the via holes, depositing thermally expandable material on the heaters, forming a nozzle at each second region by etching the thermally expandable material to define an arm suspended at one end from the circuitry layer and an inkjet port in the suspended end, and forming channels aligned with the nozzles by etching a substrate carrying the circuitry layer. Each arm is formed to have one of the heaters embedded in the thermally expandable material such that uneven expansion is caused upon heating resulting in displacement of the arm and associated inkjet port relative to the circuitry layer.

Abstract: A thermal inkjet printhead with a heater element disposed in each of the bubble forming chambers wherein, the heater element has a protective surface coating that is less than 0.1 ?m thick while still being capable of ejecting more than 1 billion drops without failure. Removing most or all of the protective coatings from the heater reduces or eliminates the thermal insulation between the heater and the ink. Nucleating a bubble in the ink chamber requires a much shorter pulse of less energy thereby improving printhead efficiency.

Abstract: A nozzle guard for a printhead is provided. The nozzle guard has a plurality of channels therethrough, each channel corresponding to a respective nozzle on the printhead such that, in use, ink droplets ejected from each nozzle pass through their respective channel towards a print medium. The channels have hydrophobic sidewalls such that ink droplets can rebound off them and be redirected.

Abstract: A thermal inkjet printhead with heater elements formed from a self passivating transition metal nitride, but it oxidizes readily. By introducing an additive that allows the metal nitride to self passivate, the heater element forms a surface oxide layer, where the oxide has a low diffusion coefficient for oxygen so as to provide a barrier to further oxidation. With enhanced oxidation resistance, coatings to protect the heater from oxidative failure become unnecessary and the energy needed to form a bubble is reduced.