An industrial printhead (100) comprising a flow channel enclosed in a chamber, wherein the flow channel (102) has at least one fluid inlet (102a) and at least one fluid outlet (102b), wherein the flow channel is resonated, in use, by a vibration distributor (104) comprising a mass resonator (103), piezoelectric exciter (108) and wave concentrator (110) arranged in an axial configuration.

A grayscale inkjet printing method including the steps of: a) supplying a pigmented inkjet ink to a grayscale print head having nozzles with an outer nozzle surface area smaller than 500 μm.sup.2 and having an acoustic resonance period ARP of not more than 5.5 μs; and b) applying a voltage wave form for ejecting pigmented inkjet ink from a nozzle of the grayscale print head within one jetting cycle; wherein the pigmented inkjet ink has a viscosity of at least 3.8 mPa.Math.s at jetting temperature and a shear rate of 1,000 s.sup.−1; wherein the voltage wave form for ejecting the largest ink droplet includes, in chronological order, a first ejecting pulse having an amplitude A1 and a second ejecting pulse having an amplitude A3 with the amplitude A1 complying with the relationship: 0.50×A3<A1<1.40×A3; and wherein a time period between the end time of the first ejecting pulse and the end time of the second ejecting pulse defines an idle time period including no other ejecting pulse, the time period having a duration between 1.5 to 2.5 times the acoustic resonance period ARP; and wherein any non-ejecting pulse having an amplitude A2 present during the idle time period complies with the relationship: A2≤0.15×A3. An inkjet printing system is also disclosed.

Provided is a liquid droplet generation method capable of generating liquid droplets having a diameter of 100 .Math.m or more. The liquid droplet generation method for generating liquid droplets from a liquid layer 20 by using a plurality of transducers 18, the method including irradiating the liquid layer 20 with a plurality of ultrasonic waves from the plurality of transducers 18 to scatter primary liquid droplets 21A and 21B from the liquid layer 20, and causing the primary liquid droplets 21A and 21B being scattered to aggregate and grow into a secondary liquid droplet 22A.

Methods of ejecting droplets containing a non-Newtonian fluid by an acoustic droplet ejector can include applying a tone burst of focused acoustic energy to a fluid reservoir containing a non-Newtonian fluid at sufficient amplitude to effect droplet ejection according to a tone burst pattern. The tone burst pattern may include three discrete tone burst segments, the first tone burst segment having greater duration than the second and third segments, and third segment having greater duration than the second segment. The exact durations and amplitudes of the tone burst segments can be tuned to influence the ejection properties.

An industrial printhead (100) comprising a flow channel enclosed in a chamber, wherein the flow channel (102) has at least one fluid inlet (102a) and at least one fluid outlet (102b), wherein the flow channel is resonated, in use, by a vibration distributor (104) comprising a mass resonator (103), piezoelectric exciter (108) and wave concentrator (110) arranged in an axial configuration.

A jetting device configured to jet one or more droplets of a viscous medium through a nozzle may include an acoustic transducer configured to emit an acoustic signal that transfers acoustic waves into at least a portion of the viscous medium located in a viscous medium conduit a viscous medium conduit configured to direct a flow of the viscous medium to an outlet of the nozzle. The acoustic signal may be an ultrasonic signal. The acoustic signal may adjust one or more rheological properties of the viscous medium, based on acoustic actuation. The acoustic transducer may be implemented by an actuator of the device that is configured to move through an eject chamber to cause viscous medium to be jetted through the outlet of the nozzle as one or more droplets.

An acoustic droplet ejection apparatus comprises an acoustic actuator and a fluid well having abase and at least one side wall. The actuator is arranged to couple acoustic energy into the fluid well through the side wall.

Devices and methods are provided for ejecting a droplet from a reservoir using focused acoustic radiation having a plurality of nonsimultaneous and discrete frequency ranges. Such frequency ranges may be used to control droplet volume and/or velocity. Optionally, satellite fluid ejection from the reservoir is suppressed.

A jetting device configured to jet one or more droplets of a viscous medium through a nozzle may include an acoustic transducer configured to emit an acoustic signal that transfers acoustic waves into at least a portion of the viscous medium located in a viscous medium conduit a viscous medium conduit configured to direct a flow of the viscous medium to an outlet of the nozzle. The acoustic signal may be an ultrasonic signal. The acoustic signal may adjust one or more rheological properties of the viscous medium, based on acoustic actuation. The acoustic transducer may be implemented by an actuator of the device that is configured to move through an eject chamber to cause viscous medium to be jetted through the outlet of the nozzle as one or more droplets.

Methods of ejecting droplets containing a non-Newtonian fluid by an acoustic droplet ejector can include applying a tone burst of focused acoustic energy to a fluid reservoir containing a non-Newtonian fluid at sufficient amplitude to effect droplet ejection according to a tone burst pattern. The tone burst pattern may include three discrete tone burst segments, the first tone burst segment having greater duration than the second and third segments, and third segment having greater duration than the second segment. The exact durations and amplitudes of the tone burst segments can be tuned to influence the ejection properties.