Method for jetting droplets of an electrically conductive fluid

Patent metadata

Field	Value
Publication number	US-9744763-B2
Application number	US-201514978771-A
Country	US
Kind code	B2
Filing date	Dec 22, 2015
Priority date	Jul 11, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

In a method for jetting a droplet of an electrically conductive fluid, a Lorentz force is generated in the electrically conductive fluid. The Lorentz force is directed into an actuation direction. The actuation direction is a direction opposite to the droplet ejection direction. A jetting device is provided for printing a droplet of an electrically conductive fluid.

First claim

The invention claimed is:

1. A method for jetting a droplet of an electrically conductive fluid using a jetting device, the jetting device comprising a fluid chamber body defining a fluid chamber and having an orifice operatively coupled to the fluid chamber for ejecting a droplet in a droplet ejection direction, and an actuator, the actuator comprising:
a magnetic field generator configured to generate a magnetic field in at least a part of the fluid chamber; and
an electrical current generator configured to generate an electrical current in the electrically conductive fluid in the part of the fluid chamber provided with the magnetic field,
the method comprising the steps of:
a) applying an electrical current to the electrically conductive fluid positioned in the magnetic field to generate a Lorentz force in an actuation direction that is an opposite direction compared to the droplet ejection direction,
wherein the Lorentz force is such that the electrically conductive fluid is retracted in the actuation direction and moved into the fluid chamber, and
b) as a result of the Lorentz force generated in step a), ejecting a droplet of the electrically conductive fluid in the droplet ejection direction.

2. The method according to claim 1 , wherein at least an inner surface of the fluid chamber body is provided with a wetting coating.

3. The method according to claim 2 , wherein the wetting coating comprises at least one of the group consisting of mono-tungsten-carbide (WC), di-tungsten-carbide W 2 C), tri-tungsten-carbide (W 3 C) and boron-nitride (BN).

4. The method according to claim 1 , wherein the electrically conductive fluid is a molten metal.

5. The method according to claim 4 , wherein the molten metal is selected from the group consisting of molten silver, molten copper and molten gold.

6. The method according to claim 1 for jetting a series of droplets of the electrically conductive fluid, the series of droplets comprising at least one small droplet and at least one large droplet, wherein the at least one small droplet is jetted in step a), and wherein,
in step a), the actuation direction is a first actuation direction and the droplet ejected is a small droplet,
and wherein the method further comprises the step of:
c) applying an electrical current to the electrically conductive fluid positioned in the magnetic field, thereby generating a Lorentz force in the electrically conductive fluid, the Lorentz force being directed in a second actuation direction, the second actuation direction being in a direction parallel to the droplet ejection direction,
as a result of the Lorentz force generated in step c), ejecting a large droplet of the electrically conductive fluid in the droplet ejection direction.

7. A jetting device for printing a droplet of an electrically conductive fluid, the jetting device comprising:
a fluid chamber body defining a fluid chamber for holding an amount of the electrically conductive fluid;
an actuation assembly configured to expel droplets of the electrically conductive fluid from the chamber through an orifice in the droplet ejection direction, the actuation assembly comprising
a magnetic field generator configured to generate a magnetic field in at least a part of the fluid chamber; and
an electrical current generator configured to generate an electrical current in the electrically conductive fluid in the part of the fluid chamber provided with the magnetic field; and
a controller configured to control at least one of the electrical current and the magnetic field to generate a Lorentz force in an actuation direction that is an opposite direction compared to the droplet ejection direction, wherein the Lorentz force is such that the electrically conductive fluid is retracted in the actuation direction and moved into the fluid chamber, and a result of the generated Lorentz force is at least one droplet being jetted in the droplet ejection direction.

Assignees

• Océ-Technologies B V

Inventors

• Joppen Sandor H G
• Wijshoff Hermanus M A

Classifications

• B22F2009/084

  combination of methods · CPC title

• B22F2009/0892

  casting nozzle; controlling metal stream in or after the casting nozzle · CPC title

• B22F9/08

  by casting, e.g. through sieves or in water, by atomising or spraying (using electric discharge B22F9/14) · CPC title

• B41J2202/04

  Heads using conductive ink · CPC title

• H05K2203/105

  Using an electrical field; Special methods of applying an electric potential · CPC title