A method of acoustophoretic printing comprises generating an acoustic field at a first end of an acoustic chamber fully or partially enclosed by sound-reflecting walls. The acoustic field interacts with the sound-reflecting walls and travels through the acoustic chamber. The acoustic field is enhanced in a chamber outlet at a second end of the acoustic chamber. An ink is delivered into a nozzle positioned within the acoustic chamber. The nozzle has a nozzle opening projecting into the chamber outlet. The ink travels through the nozzle and is exposed to the enhanced acoustic field at the nozzle opening, and a predetermined volume of the ink is ejected from the nozzle opening and out of the acoustic chamber.

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.

A jetting device configured to jet one or more droplets of a viscous medium through the outlet of a nozzle includes an energy output device. The energy output device is configured to direct a quantum of energy into at least a portion of the volume of the viscous medium jetted through the outlet to control a breaking of the droplet from the nozzle. The energy output device may include an acoustic transducer or a piezoelectric material or a laser emitter or a heater.

The present invention contains a printing apparatus and a method, e.g., for ejecting inks (i.e., pure liquids, mixtures, colloids, etc.) for a very broad range of physical properties (such as viscosity). Acoustic forces 3a may be generated by an emitter 1 and a reflector 2 to detach droplets 10 from a nozzle 6. The ink may be advanced through the nozzle 6 by a standard back pressure system 5. A reflectorless chamber 7 may enhance acoustic forces 8a and the droplets 10 may be ejected at a bottom 9 of said chamber 7, so that droplets 10 may be deposited on any substrate 11.

A subwavelength resonator for acoustophoretic printing comprises a hollow resonator body for local enhancement of an acoustic field integrated with a nozzle body for delivery of an ink into the acoustic field. The nozzle body has a first end outside the hollow resonator body and a second end inside the hollow resonator body, and includes a fluid channel extending between a fluid inlet at the first end and a fluid outlet at the second end. The fluid channel passes through a side wall of the hollow resonator body and includes at least one bend. During acoustophoretic printing, an ink delivered through the fluid channel of the nozzle body and out of the fluid outlet is exposed to a high-intensity acoustic field.

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.

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 ?m.sup.2 and having an acoustic resonance period ARP of not more than 5.5 ?s; 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.

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.