Claims
- 1. A system for separating charge-bearing particles from fluid dispersant of a liquid toner, said system comprising,
- a particle-accumulating surface,
- means for moving said particle-accumulating surface in a first direction,
- an electrode having a surface spaced from said particle-accumulating surface to define a channel therebetween,
- biasing means in communication with said electrode for creating an electric field between said surfaces and within said channel,
- means for supplying liquid toner into said channel such that said liquid toner has a tendency to flow in a second direction opposite said first direction, charge-bearing particles of said liquid toner within said channel moving in said electric field to form a concentration of particles proximate to said particle-accumulating surface, said concentration of particles adhering to said moving particle-accumulating surface to provide a particle rich slime moving in said first direction, thereby leaving a substantially particle-free flow of fluid dispersant in said second direction,
- means for removing said slime from said particle-accumulating surface at a location remote from said electrode and,
- a reservoir of charge-bearing particles in containment association with the means for removing and in contact with the particle-accumulating surface, whereby the reservoir is in fluid isolation from the channel.
- 2. The system of claim 1 wherein said particle-accumulating surface is a surface of a rotatably mounted drum and said channel has a mouth inlet in gravity-feed relation to an outlet.
- 3. The system of claim 1 wherein said electrode surface is complementary in shape to said particle accumulating surface.
- 4. The system of claim 1 wherein said means for removing said charge-bearing particles from said particle-accumulating surface is a rotary wiper having a plurality of radially extending blades disposed to serially contact said particle-accumulating surface during rotation of said wiper.
- 5. The system of claim 1 wherein said channel has first and second opposed lateral ends defined by seals, said seals being in frictional contact with said particle-accumulating surface to prevent fluid flow therebetween.
- 6. A system for removing charge-bearing solid pigment particles from a fluid dispersant in a liquid toner comprising,
- an accumulation surface,
- an electrode having a surface facing said accumulation surface in spaced apart relation thereto forming a channel therebetween, said accumulation surface and electrode being positioned relative to each other to define a mouth and an outlet such that fluid tends to flow in a first direction from said mouth to said outlet, said mouth being positioned at a level above the outlet so that the mouth is in gravity feed relation to the outlet, the outlet being in fluid communication with a fluid dispersant drain line which defines a flow path from the outlet to a trap level above the outlet,
- means for introducing said liquid toner at said mouth,
- means for applying an electric potential between said electrode surface and said accumulation surface to cause the charge-bearing pigment particles to move in an electric field established by the potential in a direction whereby said pigment particles collect on said accumulation surface,
- means for moving said accumulation surface relative to the electrode surface in a direction opposite the first direction thereby separating the pigment particles collecting thereon from liquid toner entering into said channel, and
- means for removing said pigment particles from the accumulation surface.
- 7. The system of claim 6 wherein said accumulation surface is an endless loop.
- 8. The system of claim 6 wherein said accumulation surface is the surface of a drum.
- 9. The system of claim 8 wherein said electrode surface is arcuate having a curvature such that said channel is a uniform gap between said electrode and said accumulation surface.
- 10. The system of claim 9 wherein said electrode surface has an angular extent of at least 30.degree..
- 11. The system of claim 6 wherein said means for removing said pigment particles from said accumulating surface is a rotary wiper having a plurality of radially extending blades.
- 12. The system of claim 6 wherein said trap level of the flow path is below the level of said mouth.
- 13. A method of separating charge-bearing solid pigment particles from a liquid toner comprising,
- introducing and maintaining a flow of liquid toner from an upstream end and toward a downstream end of a channel formed between an electrode and a particle-accumulating surface, said liquid toner having charge-bearing solid pigment particles dispersed in a fluid dispersant,
- moving said particle-accumulating surface past said electrode at a selected velocity in an upstream direction opposed to said flow of liquid toner,
- electrically biasing said electrode to repel said pigment particles so as to leave a stream of substantially particle-free fluid dispersant flowing through said channel adjacent to said electrode, said pigment particles thereby forming a pigment particle rich slime proximate to said particle-accumulating surface, said velocity selected to cause said slime to collect on said particle-accumulating surface moving upstream relative to said dispersant flow, thereby leaving substantially particle-free fluid dispersant at the downstream end of said channel,
- removing said substantially particle-free fluid dispersant from said downstream end, and
- removing said pigment particle-containing slime from said particle-accumulating surface after said movement past said electrode, said removing of said pigment particles being performed within a storage tank for said pigment particles.
- 14. The method of claim 13 wherein said removing of said pigment particles is performed by washing said particle accumulating surface with a rotary wiper having a plurality of radially extending blades.
- 15. The method of claim 13 wherein said removing of said particle-free fluid is accomplished by a dispersant fluid drain line in which a prescribed fluid level is maintained above said downstream end.
- 16. A system for removing charge-bearing solid pigment particles from a fluid dispersant in a liquid toner, the system comprising,
- a rotatable drum having a particle-accumulating surface,
- means for rotating the drum in a first direction,
- an electrode having a surface spaced apart from the particle-accumulating surface to define opposed sides of a channel therebetween, the electrode and drum positioned to define a mouth and an outlet to the channel,
- sealing members forming opposed lateral sides of the channel and being in frictional contact with the particle-accumulating surface to prevent fluid flow therebetween,
- means for supplying liquid toner at the mouth of the channel such that the liquid toner has a tendency to flow through the channel in a second direction opposite the first direction,
- biasing means in communication with the electrode for creating an electric field between the electrode and particle-accumulating surfaces, the electric field compelling the charge-bearing particles of the liquid toner to migrate towards the particle-accumulating surface forming a concentration of particles proximate to the particle-accumulating surface, the concentration of particles adhering to the rotating particle-accumulating surface to provide a particle rich slime moving in the first direction, thereby leaving a substantially particle-free flow of fluid dispersant in the second direction, and
- means for removing the slime from the particle-accumulating surface at a location remote from the electrode.
- 17. The system of claim 16 wherein said mouth is positioned at a level above said outlet so that said mouth is in gravity feed relation to said outlet, said outlet being in fluid communication with a fluid dispersant drain line which defines a flow path from said outlet to a trap level above said outlet.
CROSS-REFERENCE TO RELATED APPLICATION
The present application is a continuation-in-part application of U.S. application Ser. No. 077,104, filed July 23, 1987, now U.S. Pat. No. 4,799,452.
US Referenced Citations (14)
Foreign Referenced Citations (1)
Number |
Date |
Country |
54-143131 |
Nov 1979 |
JPX |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
77104 |
Jul 1987 |
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