Acoustophoretic printing apparatus and method
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 3 a 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 8 a 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.
1. A printing apparatus comprising:
an emitter arranged within a first fluid and configured to oscillate for generating an acoustic field in said first fluid;
a nozzle with a nozzle tip placed at a predetermined position within said acoustic field;
a second fluid within the nozzle, and
a driving means configured to drive a predetermined volume of the second fluid out of the nozzle,
wherein the emitter is configured to oscillate with a frequency of 1 Hz to 1 GHz.
2. The printing apparatus according to claim 1 , characterized in that a reflector is arranged between the emitter and a printing substrate.
3. The printing apparatus according to claim 2 , characterized in that a surface of the reflector is positioned at a distance (H) to the emitter, wherein the distance (H) is a multiple of λ/2±0.2λ, with λ being the wavelength of sound waves of a first acoustic field between the emitter and the reflector surface.
4. The printing apparatus according to claim 2 , characterized in that the reflector has a reflectorless chamber which is arranged along a printing axis (A) between the nozzle tip and the printing substrate, wherein the reflectorless chamber is a through-hole in a body of the reflector.
5. The printing apparatus according to claim 4 , characterized in that the predetermined position of the nozzle tip is within the reflectorless chamber in a region from an exit of the reflectorless chamber to Hh/3, with Hh being a height of the reflectorless chamber.
6. The printing apparatus according to claim 1 , characterized in that the printing apparatus comprises a plurality of emitters, wherein the emitters are arranged such that emitted sound waves are focused on a predetermined point in space within the acoustic field, and the predetermined position of the nozzle tip is at said predetermined point in space or in the vicinity thereof.
7. The printing apparatus according to claim 1 , characterized in that the acoustic field has a force gradient of acoustic forces, and the predetermined position of the nozzle tip is at a point or in the vicinity of a net force that pulls at the droplet pendant at the nozzle tip.
8. The printing apparatus according to claim 1 , characterized in that a plurality of nozzles and/or reflectorless chambers are arrayed for forming a multi-nozzle print head.
9. The printing apparatus according to claim 1 , characterized in that the nozzle has a heating means and/or a cooling means for heating/cooling the second fluid to a predetermined temperature.
10. The printing apparatus according to claim 1 , characterized in that a print head, which can be the emitter or the reflector, comprises a plurality of reflectorless chambers.
11. The printing apparatus according to claim 1 , characterized in that the nozzle and the drive means are connected via a tubing, wherein the tubing is introduced into the printing apparatus at a side surface thereof below the emitter or through a hole in the emitter.
12. The printing apparatus according to claim 1 , characterized in that the predetermined volume ranges from nl to μl.
13. The printing apparatus according to claim 1 , characterized by further comprising a control means configured to control at least the oscillation of the emitter, the pressure application of the drive means and/or a driving of the printing apparatus to a printing position in relation to a printing substrate.
14. A printing apparatus comprising:
an emitter arranged within a first fluid and configured to oscillate for generating an acoustic field in said first fluid;
a nozzle with a nozzle tip placed at a predetermined position within said acoustic field;
a second fluid within the nozzle; and
a driving means configured to drive a predetermined volume of the second fluid out of the nozzle,
wherein the acoustic field has a force gradient of acoustic forces, and the predetermined position of the nozzle tip is at a point or in the vicinity of a net force that pulls at a droplet pendant at the nozzle tip.
15. A printing apparatus comprising:
an emitter arranged within a first fluid and configured to oscillate for generating an acoustic field in said first fluid;
a nozzle with a nozzle tip placed at a predetermined position within said acoustic field;
a second fluid within the nozzle;
a driving means configured to drive a predetermined volume of the second fluid out of the nozzle; and
a control means configured to control at least an oscillation of the emitter, a pressure application of the drive means, and/or a driving of the printing apparatus to a printing position in relation to a printing substrate.