Abstract: The present disclosure provides a bioprinting system (100) for printing a liquid directly onto a subject. The bioprinting system (100) comprises a bioprinting assembly (102). Optionally, a robotic arm (104) and a control system (150) are provided. The bioprinting assembly (102) may be coupled to the robotic arm (104) to be positionable relative to the subject. The bioprinting assembly (102) is configured to dispense the liquid onto the subject and comprises a reservoir (120) for holding the liquid and a loading mechanism (134) to prime the reservoir (120) with the liquid directly prior to printing. The loading mechanism (134) has a one way inlet to permit liquid to be loaded into the reservoir (120) and prevent fluid from exiting the reservoir via the one way inlet. There is also provided associated methods.

Abstract: A bioprinter for fabricating three-dimensional (3D) cell constructs, the bioprinter comprising one or more holding reservoirs for holding a fluid sample; a printstage for holding a sample container and supporting a substrate on which a 3D cell construct is to be printed; a sample loading system in fluid communication with the one or more holding reservoirs, the sample loading system configured to load a sample from a sample container into the one or more holding reservoirs; a pump in fluid communication with the sample loading system, the pump configured to draw the sample out of a sample container and pump the sample into the one or more holding reservoirs; and a droplet dispensing system in fluid communication with the one or more reservoirs, the droplet dispensing system configured to print sample droplets from the one or more reservoirs onto a substrate supported by the printstage.

Abstract: A method of operating an inkjet printhead having a plurality of ink chambers, each ink chamber including a heater element for generating a bubble and causing ejection of ink droplets from a nozzle defined in the ink chamber. The method includes the steps of: operating the printhead in a normal printing mode whereby relatively shorter drive pulses are delivered to the heater elements to eject ink droplets used in normal printing; and operating the printhead in a maintenance mode whereby relatively longer drive pulses are delivered to the heater elements. The relatively longer drive pulses generate high impulse bubbles for recovering nozzles affected by decap.

Abstract: A method of operating an inkjet printhead having a plurality of ink chambers, each ink chamber including a heater element for generating a bubble and causing ejection of ink droplets from a nozzle defined in the ink chamber. The method includes the steps of: operating the printhead in a normal printing mode whereby relatively shorter drive pulses are delivered to the heater elements to eject ink droplets used in normal printing; and operating the printhead in a maintenance mode whereby relatively longer drive pulses are delivered to the heater elements. The relatively longer drive pulses generate high impulse bubbles for recovering nozzles affected by decap.

Abstract: An inkjet nozzle assembly includes: a nozzle chamber having a planar roof spaced apart from a floor, the roof having a nozzle aperture defined therein; and a heater element disposed in the nozzle chamber, the heater element being configured as a planar beam extending longitudinally and parallel with a plane of the roof. The nozzle aperture is elliptical having a centroid, a major axis and a minor axis, the major axis of the nozzle aperture is parallel with a longitudinal axis of the beam, the centroid of the nozzle aperture is offset from a longitudinal centroid of the planar beam, and the minor axis of the nozzle aperture overlaps with a whole width of the beam.

Abstract: A printhead is provided having fluid ejection nozzles, heaters corresponding to each of the nozzles respectively, with each heater heating printing fluid to cause ejection of a drop of the printing fluid through the corresponding nozzle, and circuitry for generating electrical drive pulses having variable power and length for energizing the heaters. The drive pulses are generated to have less energy than the energy required to heat a volume of the printing fluid equivalent to the drop volume, from the temperature at which the printing fluid enters the printhead to the heterogeneous boiling point of the printing fluid.

Abstract: An inkjet nozzle assembly includes a nozzle chamber having a planar roof spaced apart from a floor. A heater element is suspended in the nozzle chamber and is configured as a planar beam extending longitudinally and parallel with a plane of the roof. A nozzle aperture defined in the roof has a centroid offset from a longitudinal centroid of the planar beam.

Abstract: An inkjet printer that has a printhead with a nozzle array for ejecting droplets of ink onto a media substrate, a media feed assembly for feeding media passed the printhead in a media feed direction such that the nozzle array and the media substrate are separated by a print gap and, an air flow generation mechanism for generating an air flow in the print gap opposite to the media feed direction.

Abstract: An inkjet printer that has a printhead with a nozzle array for ejecting droplets of ink onto a media substrate, a media feed assembly for feeding media passed the printhead in a media feed direction such that the nozzle array and the media substrate are separated by a print gap and, an air flow generation mechanism for generating an air flow in the print gap opposite to the media feed direction.

Abstract: A printhead is provided having vapor bubble generators which each have a chamber having a fluid ejection port and a heater, and circuitry configured to provide current pulses to the heater to generate vapor bubbles in fluid within the chamber. The pulses have a heating pulse of a first voltage and duration immediately followed by an ejection pulse of a second voltage and duration, the second voltage being higher than the first voltage.

Abstract: A printhead is provided having fluid ejection nozzles, heaters corresponding to each of the nozzles respectively, with each heater heating printing fluid to cause ejection of a drop of the printing fluid through the corresponding nozzle, and circuitry for generating electrical drive pulses having variable power and length for energizing the heaters. The drive pulses are generated to have less energy than the energy required to heat a volume of the printing fluid equivalent to the drop volume, from the temperature at which the printing fluid enters the printhead to the heterogeneous boiling point of the printing fluid.

Abstract: The invention provides for an inkjet printhead having a plurality of micro-electromechanical vapor bubble generators. Each bubble generator includes a nozzle in fluid communication with an ink chamber, and a heater positioned in thermal contact with ink in the chamber. Each generator also includes drive circuitry configured to provide a modulated pulse to the heater to generate a vapor bubble in the ink in said chamber, the pulse comprising a pre-heat series of a predetermined number of pulses separated by a predetermined period, followed by a trigger pulse of a period twice that of said predetermined period.

Abstract: An inkjet printhead with an array of nozzles 26 and corresponding heaters 10 configured for heating printing fluid 20 to nucleate a vapor bubble 12 that ejects a drop 24 of the printing fluid through the nozzle. Drive circuitry 22 generates an electrical drive pulse to energize the heaters 10 and is configured to adjust the drive pulse power to vary the vapor bubble nucleation time. By varying the power of the pulse used to generate the bubble, the printhead can operate with small, efficiently generated bubbles during normal printing, or it can briefly operate with large high energy bubbles if it needs to recover decapped nozzles.

Abstract: An inkjet nozzle assembly includes a nozzle chamber having a planar roof spaced apart from a floor. A heater element is suspended in the nozzle chamber and is configured as a planar beam extending longitudinally and parallel with a plane of the roof. A nozzle aperture defined in the roof has a centroid offset from a longitudinal centroid of the planar beam.

Abstract: A thermal inkjet printhead of the roof shooter type that slightly offsets the nozzle aperture centroid from the heater element centroid to correct drop trajectory misdirection caused by vapor bubble asymmetries.

Abstract: An inkjet printhead with an array of nozzles 26 and corresponding heaters 10 configured for heating printing fluid 20 to nucleate a vapor bubble 12 that ejects a drop 24 of the printing fluid through the nozzle. Drive circuitry 22 generates an electrical drive pulse to energize the heaters 10 and is configured to adjust the drive pulse power to vary the vapor bubble nucleation time. By varying the power of the pulse used to generate the bubble, the printhead can operate with small, efficiently generated bubbles during normal printing, or it can briefly operate with large high energy bubbles if it needs to recover decapped nozzles.

Abstract: A MEMS vapour bubble generator that uses a heater in thermal contact with a liquid to generate a bubble. The heater is energized by an electrical pulse that is shaped to have a relatively low power, sub-nucleating portion and a high power portion that nucleates the bubble. The thermal energy transferred to the liquid by the sub-nucleating portion speeds up the nucleation of the bubble across the surface of the heater during the nucleating portion. This produces larger, more stable bubble having a regular shape.

Abstract: A thermal inkjet printhead of the roof shooter type that slightly offsets the nozzle aperture centroid from the heater element centroid to correct drop trajectory misdirection caused by vapor bubble asymmetries.

Abstract: The invention provides for an inkjet printhead having a plurality of micro-electromechanical vapor bubble generators. Each bubble generator includes a nozzle in fluid communication with an ink chamber, and a heater positioned in thermal contact with ink in the chamber. Each generator also includes drive circuitry configured to provide a modulated pulse to the heater to generate a vapor bubble in the ink in said chamber, the pulse comprising a pre-heat series of a predetermined number of pulses separated by a predetermined period, followed by a trigger pulse of a period twice that of said predetermined period.