Abstract: A fluid ejection device includes a fluid manifold, a substrate coupled to the fluid manifold, and a fluid distribution structure disposed between the fluid manifold and the substrate. The fluid manifold includes a fluid supply chamber and a fluid return chamber. The substrate defines a flow path including a flow path inlet for receiving fluid, a nozzle for ejecting fluid droplets, and a flow path outlet for channeling away un-ejected fluid. The fluid distribution structure includes a fluid supply channel including a supply inlet fluidically coupled to the fluid supply chamber and a supply outlet fluidically coupled to the flow path. The fluid distribution structure also includes a fluid bypass channel including a bypass inlet fluidically coupled to the fluid supply chamber, a bypass outlet fluidically coupled to the fluid return chamber, and a flow inhibitor between the bypass inlet and the bypass outlet providing a supplemental flow resistance to the fluid bypass channel.

Abstract: Among other things, a device for use in printing is described. The device comprises a first chamber for receiving a liquid and a first filter member in the first chamber. The first filter member separates the first chamber into a first part and a second part laterally adjacent to the first part. The first filter member comprises pores having an average size. The pores are configured to filter the liquid passing from the first part to the second part. The first filter member further comprises an opening adjacent to a top of the first chamber for air to pass from the first part to the second part. The opening has a size at least 10 times larger than the average size of the pores. There is a first inlet in fluid communication with the first part and a first outlet in fluid communication with the second part.

Abstract: Systems and apparatus for ejecting fluid. A fluid injection apparatus includes a fluid ejector unit for ejecting a droplet of fluid, an integrated circuit, and a conductive trace electrically coupling the fluid ejector unit and the integrated circuit. A portion of the conductive trace includes a fuse.

Abstract: A fluid ejection apparatus includes a substrate having a plurality of fluid passages for fluid flow and a plurality of nozzles fluidically connected to the fluid passages, a plurality of actuators positioned on top of the substrate to cause fluid in the plurality of fluid passages to be ejected from the plurality of nozzles, a housing component with a descending portion that projects down to the substrate, an integrated circuit chip supported on the substrate, a potting barrier secured to the housing component and positioned between the integrated circuit chip and the actuators, and a potting material between the integrated circuit chip and the barrier.

Abstract: A method of determining whether a flow path is ready for ejection includes supplying liquid to the flow path, which includes a pumping chamber and a nozzle, after supplying fluid to the flow path, applying energy to an actuator adjacent to the pumping chamber, measuring an electrical characteristic of the actuator to obtain a measured value, and comparing the measured value to a threshold value to determine if the flow path is ready for ejection.

Abstract: Methods, systems, and apparatus for drive a pumping chamber of a fluid ejection system are disclosed. In one implementation, the actuator for drive the pumping chamber includes a continuous piezoelectric layer between a pair of drive electrodes and a continuous reference electrode. The pair of drive electrodes includes an inner electrode and an outer electrode surrounding the inner electrode. The actuator is further coupled to a controller which, during a fluid ejection cycle, applies a negative voltage pulse differential to the outer electrode to expand the pumping chamber for a first time period, then applies another negative voltage pulse differential to the inner electrode during a second time period after the first time period to contract the pumping chamber to eject a fluid drop.

Abstract: A fluid ejection apparatus includes a substrate having a plurality of fluid passages for fluid flow and a plurality of nozzles fluidically connected to the fluid passages, a plurality of actuators positioned on top of the substrate to cause fluid in the plurality of fluid passages to be ejected from the plurality of nozzles, and a protective layer formed over at least a portion of the plurality of actuators, the protective layer having an intrinsic permeability to moisture less than 2.5×10?3 g/m·day.

Abstract: A system for ejecting droplets of a fluid is described. The system includes a substrate having a flow path body that includes a fluid pumping chamber, a descender fluidically connected to the fluid pumping chamber, and a nozzle fluidically connected to the descender. The nozzle is arranged to eject droplets of fluid through an outlet formed in an outer substrate surface. The flow path body also includes a recirculation passage fluidically connected to the descender. The system for ejecting droplets of a fluid also includes a fluid supply tank fluidically connected to the fluid pumping chamber, a fluid return tank fluidically connected to the recirculation passage, and a pump fluidically connecting the fluid return tank and the fluid supply tank. In some implementations, a flow of fluid through the flow path body is at a flow rate sufficient to force air bubbles or contaminants through the flow path body.

Abstract: A fluid ejector having an inner surface, an outer surface, and an orifice that allows fluid in contact with the inner surface to be ejected. The fluid ejector has a non-wetting monolayer covering at least a portion of the outer surface of the fluid ejector and surrounding an orifice in the fluid ejector. Fabrication of the non-wetting monolayer can include removing a non-wetting monolayer from a second region of a fluid ejector while leaving the non-wetting monolayer on a first region surrounding an orifice in the fluid ejector, or protecting a second region of a fluid ejector from having a non-wetting monolayer formed thereon, wherein the second region does not include a first region surrounding the orifice in the fluid ejector.

Abstract: An apparatus, method, and a fluid ejection system for detecting electrical shorts in piezoelectric printheads are described. An apparatus includes a piezoelectric actuator, a transistor whose drain is connected to the piezoelectric actuator, a diode that is connected to a source and the drain of the transistor, a detection circuit configured to detect whether a voltage at the drain of the transistor is above a predefined voltage, and a disabling circuit configured to turning off the transistor in response to detecting that voltage at the drain of the transistor is above the predefined voltage.

Abstract: A fluid ejector head includes a die with a plurality of fluid ejector units, each fluid ejector unit comprising a pumping actuator having a drive electrode, and a manifold that contacts the first side of the die to define a module volume in fluidic communication with a drainage volume. The module volume is defined in part between the manifold and at least a portion of plurality of fluid ejector units, and the drainage volume is located apart from the fluid ejector units. The module volume, in comparison to the drainage volume, has a greater ratio of interior surface area to volume or has a greater percentage of interior surface area covered by a non-wetting coating.

Abstract: Processes for forming an actuator having a curved piezoelectric membrane are disclosed. The processes utilize a profile-transferring substrate having a curved surface surrounded by a planar surface to form the curved piezoelectric membrane. The piezoelectric material used for the piezoelectric actuator is deposited on at least the curved surface of the profile-transferring substrate before the profile-transferring substrate is removed from the underside of the curved piezoelectric membrane. The resulting curved piezoelectric membrane includes grain structures that are columnar and aligned, and all or substantially all of the columnar grains are locally perpendicular to the curved surface of the piezoelectric membrane.

Abstract: A piezoelectric ink jet head that includes a polymer film, for example a flex print, located between the piezoelectric element and the reservoirs in the jet body. The film provides an efficient seal for the reservoirs and also positions the electrodes on the side of the piezoelectric element in which motion is effected, which can reduce the magnitude of the drive voltage. This location of the compliant flex print material also can enhance electrical and mechanical isolation between reservoirs, which improves jetting accuracy. The compliance of the polymer also reduces strain on the ink jet head.

Abstract: A method for driving a droplet ejection device having an actuator, including applying a primary drive pulse to the actuator to cause the droplet ejection device to eject a droplet of fluid in a jetting direction, and applying one or more secondary drive pulses to the actuator which reduce a length of the droplet in the jetting direction without substantially changing a volume of the droplet.

Abstract: In general, in one aspect, the invention features a method for driving a droplet ejection device having an actuator, including applying a multipulse waveform that includes two or more drive pulses to the actuator to cause the droplet ejection device to eject a single droplet of a fluid, wherein a frequency of the drive pulses is greater than a natural frequency, fj, of the droplet ejection device.

Abstract: A fluid ejection apparatus includes a substrate having a plurality of fluid passages for fluid flow and a plurality of nozzles fluidically connected to the fluid passages, a plurality of actuators positioned on top of the substrate to cause fluid in the plurality of fluid passages to be ejected from the plurality of nozzles, and a protective layer formed over at least a portion of the plurality of actuators, the protective layer having an intrinsic permeability to moisture less than 2.5×10?3 g/m·day.

Abstract: Methods, systems, and apparatus for drive a pumping chamber of a fluid ejection system are disclosed. In one implementation, the actuator for drive the pumping chamber includes a continuous piezoelectric layer between a pair of drive electrodes and a continuous reference electrode. The pair of drive electrodes includes an inner electrode and an outer electrode surrounding the inner electrode. The actuator is further coupled to a controller which, during a fluid ejection cycle, applies a negative voltage pulse differential to the outer electrode to expand the pumping chamber for a first time period, then applies another negative voltage pulse differential to the inner electrode during a second time period after the first time period to contract the pumping chamber to eject a fluid drop.

Abstract: A fluid droplet ejection apparatus includes a substrate having a fluid inlet passage, a plurality of nozzles, and a plurality of flow paths each fluidically connecting the fluid inlet passage to an associated nozzle of the plurality of nozzles. Each flow path includes a pumping chamber connected to the associated nozzle and an ascender fluidically connected between the fluid inlet passage and the pumping chamber. The ascender is located proximate to an outside edge of the fluid inlet passage.

Abstract: Techniques are provided for forming nozzles in a microelectromechanical device. The nozzles are formed in a layer prior to the layer being bonded onto another portion of the device. Forming the nozzles in the layer prior to bonding enables forming nozzles that have a desired depth and a desired geometry. Selecting a particular geometry for the nozzles can reduce the resistance to ink flow as well as improve the uniformity of the nozzles across the microelectromechanical device.

Abstract: A fluid ejection apparatus includes a substrate having a nozzle surface and a passage through the substrate for fluid flow, the passage having a nozzle that includes an opening in the nozzle surface of the substrate, and an actuator to cause fluid in the passage to be ejected from the nozzle. The nozzle includes side walls extending away from the opening, the side walls sloping outwardly as the side walls extend away. An aspect ratio of a length of the opening to a width of the opening is at least 2:1.