Concentrating substances

Patent metadata

Field	Value
Publication number	US-9327295-B2
Application number	US-201214416850-A
Country	US
Kind code	B2
Filing date	Jul 24, 2012
Priority date	Jul 24, 2012
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

The present disclosure relates to a method for concentrating a substance, which may be an electrostatic printing ink. An apparatus for concentrating a substance is also described.

First claim

The invention claimed is:

1. A method for concentrating a substance, wherein the method comprises the steps of:
(a) providing the substance, the substance comprising chargeable particles in a liquid carrier;
(b) passing the substance between a conveyor and a first electrode, wherein a potential is applied between the conveyor and the first electrode such that the substance becomes adhered to the conveyor, and wherein some liquid carrier may be removed from the substance on the conveyor;
(c) passing the substance on the conveyor past a moving surface, wherein the substance contacts the moving surface and a potential is applied between the conveyor and the moving surface, such that the chargeable particles are disposed to move toward the conveyor and some of the liquid carrier is removed to increase the concentration of the chargeable particles in the liquid carrier on the conveyor to form a concentrated substance on the conveyor, the conveyor and the moving surface then diverging from one another;
(d) removing at least some of the concentrated substance from the conveyor; and
(e) wherein at least some of the liquid carrier removed from the conveyor in step (b) or step (c) is passed between a second electrode and the conveyor without being returned to a source of the substance, and a potential is applied between the conveyor and the second electrode such that the chargeable particles are disposed to move toward the conveyor, and some liquid carrier is removed.

2. The method according to claim 1 , wherein the second electrode is stationary relative to the conveyor, and is separated therefrom by a gap through which liquid carrier is passed in step (e), and in at least part of a region of the gap, has a shape that corresponds to a shape of the nearest surface of the conveyor.

3. The method according to claim 1 , wherein a gap is provided between the second electrode and conveyor, and the liquid carrier in step (e) is fed into the gap in a direction substantially opposite to the direction of movement of the conveyor past the second electrode.

4. The method according to claim 1 , wherein a potential difference applied between the conveyor and the second electrode is 500 V to 6000 V.

5. The method according to claim 4 , wherein the shortest distance between the second electrode and the conveyor is from 0.5 to 2 mm.

6. The method according to claim 1 , wherein the substance is an electrostatic ink composition comprising the chargeable particles in the liquid carrier.

7. The method according to claim 1 , wherein liquid carrier removed from the conveyor in step (b) or step (c) is passed between the second electrode and the conveyor if it has a solids content at or below a threshold value.

8. The method according to claim 1 , wherein a plurality of moving surfaces are provided in series at or near an outer surface of the conveyor, and each moving surface forms part of a moving body in the form of a rotatable drum, and wherein the liquid carrier removed from the drum closest to the first electrode is recirculated to the first electrode, and at least some of the liquid carrier removed from the other drum or drums is passed between the second electrode and the conveyor in step (e).

9. The method according to claim 8 , wherein each of the plurality of drums has a metal core with an outer surface layer comprising an elastomeric material.

10. The method according to claim 1 , wherein the conveyor comprises a metal core having a surface covering of a non-metallic, elastomeric or non-elastomeric material.

11. The method according to claim 1 , wherein the conveyor comprises an aluminium core, which has a Type III anodised surface covering.

12. The method according to claim 1 , wherein the chargeable particles comprises a resin comprising a polymer that is a copolymer of ethylene or propylene and an ethylenically unsaturated acid of either acrylic acid or methacrylic acid.

13. An apparatus for concentrating a substance, the apparatus comprising a conveyor, a first electrode, a moving surface, a concentrated substance removal means, and a second electrode, wherein a gap is provided between the second electrode and the conveyor, and wherein the apparatus is adapted to carry out a method comprising the steps of:
(a) passing the substance between the conveyor and the first electrode, wherein the substance comprises chargeable particles in a liquid carrier, and a potential is applied between the conveyor and the first electrode such that the substance becomes adhered to the conveyor, and some liquid carrier may be removed from the substance on the conveyor;
(b) passing the substance on the conveyor past the moving surface, wherein the substance contacts the moving surface and a potential is applied between the conveyor and the moving surface, such that the chargeable particles are disposed to move toward the conveyor and some of the liquid carrier is removed to increase the concentration of the chargeable particles in the liquid carrier on the conveyor to form a concentrated substance on the conveyor, the conveyor and the moving surface then diverging from one another, such that at least some of the concentrated substance remains on the conveyor;
(c) removing at least some of the concentrated substance from the conveyor by the concentrated substance removal means; and
(d) wherein at least some of the liquid carrier that is removed from the conveyor in step (a) or step (b) is passed between the second electrode and the conveyor, wherein a potential is applied between the conveyor and second electrode such that the chargeable particles are disposed to move toward the conveyor, and some carrier liquid is removed, and wherein the apparatus can feed the liquid carrier in step (d) into the gap in a direction substantially opposite to the direction of movement of the conveyor past the second electrode.

14. A method for concentrating a substance, wherein the method comprises the steps of:
(a) providing the substance, the substance comprising chargeable particles in a liquid carrier;
(b) passing the substance between a conveyor and a first electrode, wherein a potential is applied between the conveyor and the first electrode such that the substance becomes adhered to the conveyor, and wherein some liquid carrier may be removed from the substance on the conveyor;
(c) passing the substance on the conveyor past a moving surface, wherein the substance contacts the moving surface and a potential is applied between the conveyor and the moving surface, such that the chargeable particles are disposed to move toward the conveyor and some of the liquid carrier is removed to increase the concentration of the chargeable particles in the liquid carrier on the conveyor to form a concentrated substance on the conveyor, the conveyor and the moving surface then diverging from one another; and
(d) removing at least some of the concentrated substance from the conveyor;
wherein a gap is provided between a second electrode and the conveyor, and at least some of the liquid carrier removed from the conveyor in step (b) or step (c) is fed into the gap in a direction substantially opposite to the direction of movement of the conveyor past the second electrode, and a potential is applied between the conveyor and the second electrode such that the chargeable particles are disposed to move toward the conveyor, and some liquid carrier is removed.

15. The method according to claim 14 , wherein liquid carrier is collected after it has travelled a length of the second electrode in a direction opposite to the direction of movement of the conveyor past the second electrode.

Assignees

• Lior Shai
• Schneider Avner
• Sandler Mark
• Peri Yaron
• Hewlett Packard Indigo Bv

Inventors

• Lior Shai
• Schneider Avner
• Sandler Mark
• Peri Yaron

Classifications

• G03G9/0804

  whereby the components are brought together in a liquid dispersing medium · CPC title

• G03G15/105 Primary

  Detection or control means for the toner concentration · CPC title

• B03C5/026

  using open-gradient differential dielectric separation, i.e. using electrodes of special shapes for non-uniform field creation, e.g. Fluid Integrated Circuit [FIC] · CPC title

• G03G9/0802 Primary

  Preparation methods · CPC title

• G03G15/11

  Removing excess liquid developer, e.g. by heat · CPC title