Patent US5815178A successfully refreshed from Google Patents.
US5815178A
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Printing method and apparatus employing electrostatic drop separation
Assignee: Eastman Kodak Co
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Filing: 1996-04-09
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Granted: 1998-09-29
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Expires: 2016-04-09
Abstract
Abstract A constant electric field is applied to a drop on demand print head using coincident force address of selected ink drops. This field can be generated by applying one electric potential to the print head, and a different electric potential to a platen which lies on the opposite side of the recording medium. This field does not need to be modulated, or turned on for each drop to be ejected. As a result, a simple high voltage power supply can be used to generate the electric field. No high voltage switching equipment is required. Also, the spacing between nozzles can be small, as the field applied to a nozzle does not need to be separated from fields applied to adjacent nozzles. The electric field is set to be insufficient to cause ink drops to be drawn from the print head when the ink in the nozzles in the quiescent position. The drop selection method causes the ink meniscus of selected drops to protrude from the front surface of the print head. Charge accumulates at the meniscus of the protruding drop, because the drop radius is small, and because the drop meniscus is the closest point to the opposite electrode. This charge concentrates the force produced by the electric potential field onto the selected drop. This force, in combination with the ink pressure, overcomes the surface tension of the ink, and causes the selected drop to separate from the body of ink. The selected drop then accelerates towards the platen, striking the recording medium. By this means, a drop of can be printed on a print medium even when the drop selection method does not impart sufficient kinetic energy to the selected drop to cause the selected drop to overcome surface tension forces and separate from the body of ink.
Inventors
- 👤 Kia Silverbrook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 17:01
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/135; B41J2/14; B41J2/14451; B41J2/015; B41J2/04; B41J2/06; B41J2/065
Claims Analysis
Total Claims: 46
Claim 1
Independent Claim
163 words
A drop on demand printing apparatus comprising: (a) nozzle means including an array of closely spaced drop ejection orifices; (b) manifold means for supplying a body of ink in common communication with the orifices of said nozzle means; (c) means for applying a positive pressure to the body of ink in said manifold means, sufficient to cause ink to protrude from said orifices; (d) address means for energizing ink in selected orifices to cause the energized ink to protrude further from the selected orifices under the influence of the positive pressure applied to the body of ink; and (e) means for producing an electric field between ink in said orifices and a print station spaced opposite said nozzle means, said electric field being sufficient to attractively separate an ink drop from such further protruding ink in selected orifices, said address mean being capable of causing the energized ink to protrude further from the selected orifices even in the absence of the electric field.
Claim 2
Dependent Claim
163 words
A drop on demand printing apparatus comprising: (a) nozzle means including an array of closely spaced drop ejection orifices; (b) manifold means for supplying a body of ink in common communication with the orifices of said nozzle means; (c) means for applying a positive pressure to the body of ink in said manifold means, sufficient to cause ink to protrude from said orifices; (d) address means for energizing ink in selected orifices to cause the energized ink to protrude further from the selected orifices under the influence of the positive pressure applied to the body of ink; and (e) means for producing an electric field between ink in said orifices and a print station spaced opposite said nozzle means, said electric field being sufficient to attractively separate an ink drop from such further protruding ink in selected orifices, said address mean being capable of causing the energized ink to protrude further from the selected orifices even in the absence of the electric field.
Claim 3
Dependent Claim
36 words
The invention defined in claim 1 wherein the magnitude of said positive pressure and said electric field are selected to be insufficient to cause separation of an ink drop from said ink body in unselected orifices.
Claim 4
Dependent Claim
23 words
The invention defined in claim 2 wherein said address comprises means for heating ink at a position proximate the egress of selected orifices.
Claim 5
Dependent Claim
22 words
The invention defined in claim 3 wherein energy applied by said address means is less than about 2 microjoules per drop separation.
Claim 6
Dependent Claim
21 words
The invention defined in claim 1 wherein said electric field is in the range of between about 500V/mm and about 2,000V/mm.
Claim 7
Dependent Claim
26 words
The invention defined in claim 5 wherein the spacing between said orifices and said print station is in the range from about 0.3 to 1.0 mm.
Claim 8
Dependent Claim
16 words
The invention defined in claim 6 wherein the orifices have a radius of about 20 μm.
Claim 9
Dependent Claim
16 words
The invention defined in claim 2 wherein said positive pressure is at least 2% above ambient.
Claim 10
Dependent Claim
13 words
The invention defined in claim 2 wherein said pressure is approximately 1.1 atmospheres.
Claim 11
Dependent Claim
21 words
The invention defined in claim 3 wherein said address means has a pulse power of about 6 mA per selected orifice.
Claim 12
Dependent Claim
17 words
The invention defined in claim 3 wherein said address means has a pulse voltage of about 10V.
Claim 13
Dependent Claim
17 words
The invention defined in claim 3 wherein said address means applies about 1 μJ per drop separation.
Claim 14
Independent Claim
170 words
A method of separating selected drops from a body of ink in a print head having an array of orifices and an ink manifold communication with each orifice, said method including the steps of: (a) applying a positive pressure to ink in the manifold sufficient to cause ink to protrude from all of the orifices to a first position; (b) causing said ink to protrude further than said first position from selected ones of the orifices of said print head under the influence of the positive pressure under the influence of the positive pressure; and (c) applying a uniform electrostatic field to ink in both the selected and unselected orifices, the field strength of said electrostatic field being sufficient to move drops of ink from the selected orifices far enough from said body of ink so that drop separation occurs, said field strength also being insufficient to cause drops to separate from said body of ink at unselected orifices, step (b) being effective even in the absence of step (c).
Claim 15
Independent Claim
170 words
A method of separating selected drops from a body of ink in a print head having an array of orifices and an ink manifold communication with each orifice, said method including the steps of: (a) applying a positive pressure to ink in the manifold sufficient to cause ink to protrude from all of the orifices to a first position; (b) causing said ink to protrude further than said first position from selected ones of the orifices of said print head under the influence of the positive pressure under the influence of the positive pressure; and (c) applying a uniform electrostatic field to ink in both the selected and unselected orifices, the field strength of said electrostatic field being sufficient to move drops of ink from the selected orifices far enough from said body of ink so that drop separation occurs, said field strength also being insufficient to cause drops to separate from said body of ink at unselected orifices, step (b) being effective even in the absence of step (c).
Claim 16
Dependent Claim
35 words
The method as claimed in claim 13 where said causing step comprises applying a positive pressure of about 1.1 atmospheres to ink in said manifold and heating ink in said orifices with about 1 μJ.
Claim 17
Dependent Claim
20 words
The method defined in claim 13 wherein said electric field has a strength of between about 500V/mm and about 2,000V/mm.
Claim 18
Dependent Claim
159 words
A drop on demand printer which includes an array of nozzles and means for supplying a body of ink to said nozzles, said printer comprising: (a) ink pressurizing means for causing ink to protrude from unselected ones of said nozzles to a first region; (b) selection means, cooperating with the ink pressurizing means, for causing ink to protrude from selected ones of said nozzles to a second, further region; and (c) means for applying an electric field to selected ink protruding from unselected nozzles, the electric field having a field strength sufficient to move ink protruding from selected nozzles far enough from said body of ink so that drop separation occurs, said field strength being insufficient to cause ink protruding from unselected nozzles to separate from said body of ink, said selection means being capable of causing ink to protrude to the second region from the selected ones of said nozzles even in the absence of the electric field.
Claim 19
Dependent Claim
159 words
A drop on demand printer which includes an array of nozzles and means for supplying a body of ink to said nozzles, said printer comprising: (a) ink pressurizing means for causing ink to protrude from unselected ones of said nozzles to a first region; (b) selection means, cooperating with the ink pressurizing means, for causing ink to protrude from selected ones of said nozzles to a second, further region; and (c) means for applying an electric field to selected ink protruding from unselected nozzles, the electric field having a field strength sufficient to move ink protruding from selected nozzles far enough from said body of ink so that drop separation occurs, said field strength being insufficient to cause ink protruding from unselected nozzles to separate from said body of ink, said selection means being capable of causing ink to protrude to the second region from the selected ones of said nozzles even in the absence of the electric field.
Claim 20
Dependent Claim
161 words
A drop on demand printing apparatus comprising: (a) a print head including an array of closely spaced drop ejection orifices; (b) a manifold adapted to supply a body of ink in common communication with the orifices of said print head, the ink being supplied under positive pressure sufficient to cause ink to protrude from the orifices; (c) an addressable control adapted to energize ink in selected ones of said orifices to cause the ink to protrude further from selected ones of said orifices under the influence of the positive pressure of the ink; and (d) a power supply adapted to produce an electric field between ink in said orifices and a print station spaced opposite the print head sufficient to attractively separate and ink drop from such further protruding ink in selected nozzles, said addressable control being capable of causing the energized ink to protrude further from the selected ones of said orifices even in the absence of the electric field.
Claim 21
Dependent Claim
161 words
A drop on demand printing apparatus comprising: (a) a print head including an array of closely spaced drop ejection orifices; (b) a manifold adapted to supply a body of ink in common communication with the orifices of said print head, the ink being supplied under positive pressure sufficient to cause ink to protrude from the orifices; (c) an addressable control adapted to energize ink in selected ones of said orifices to cause the ink to protrude further from selected ones of said orifices under the influence of the positive pressure of the ink; and (d) a power supply adapted to produce an electric field between ink in said orifices and a print station spaced opposite the print head sufficient to attractively separate and ink drop from such further protruding ink in selected nozzles, said addressable control being capable of causing the energized ink to protrude further from the selected ones of said orifices even in the absence of the electric field.
Claim 22
Dependent Claim
41 words
The invention defined in claim 17 wherein the magnitude of said positive pressure and said electric field are selected to be insufficient to cause separation of an ink drop from said ink body in absence of energization by said addressable control.
Claim 23
Dependent Claim
25 words
The invention defined in claim 18 wherein said addressable control comprises a plurality of selectively energized heaters in thermal contact with ink in selected orifices.
Claim 24
Dependent Claim
22 words
The invention defined in claim 19 wherein energy applied by said addressable control is less than about 2 microjoules per drop ejection.
Claim 25
Dependent Claim
21 words
The invention defined in claim 17 wherein said electric field is in the range of between about 500V/mm and about 2,000V/mm.
Claim 26
Dependent Claim
26 words
The invention defined in claim 21 wherein the spacing between said orifices and said print station is in the range from about 0.3 to 1.0 mm.
Claim 27
Dependent Claim
18 words
The invention defined in claim 22 wherein the orifices are round, with a radius of about 20 μm.
Claim 28
Dependent Claim
16 words
The invention defined in claim 17 wherein said positive pressure is at least 2% above ambient.
Claim 29
Dependent Claim
13 words
The invention defined in claim 17 wherein said pressure is approximately 1.1 atmospheres.
Claim 30
Dependent Claim
20 words
The invention defined in claim 19 wherein said addressable control has a pulse power of about 6 mA per heater.
Claim 31
Dependent Claim
17 words
The invention defined in claim 19 wherein said addressable control has a pulse voltage of about 10V.
Claim 32
Dependent Claim
17 words
The invention defined in claim 19 wherein said addressable control applies about 1 μJ per drop separation.
Claim 33
Dependent Claim
121 words
A drop on demand printer which includes an array of nozzles and a supply of ink to said array, said printer comprising: (a) a pressure source for applying sufficient above ambient pressure to the ink supply to cause ink to protrude from all nozzles to a first region to form a meniscus with an air/ink interface; (b) a control operable upon the air/ink interface to cause the meniscus to protrude from selected ones of the nozzles to a second, further region; and (c) a power supply adapted to produce an electric field between ink in said orifices and a print station spaced opposite the nozzle array sufficient to attractively separate an ink drop from such further protruding ink in selected nozzles.
Claim 34
Dependent Claim
121 words
A drop on demand printer which includes an array of nozzles and a supply of ink to said array, said printer comprising: (a) a pressure source for applying sufficient above ambient pressure to the ink supply to cause ink to protrude from all nozzles to a first region to form a meniscus with an air/ink interface; (b) a control operable upon the air/ink interface to cause the meniscus to protrude from selected ones of the nozzles to a second, further region; and (c) a power supply adapted to produce an electric field between ink in said orifices and a print station spaced opposite the nozzle array sufficient to attractively separate an ink drop from such further protruding ink in selected nozzles.
Claim 35
Dependent Claim
136 words
A printer comprising: (a) a plurality of drop-emitter nozzles; (b) a body of ink associated with said nozzles; (c) a pressurizing device adapted to subject ink in said body of ink to a pressure of at least 2% above ambient pressure, at least during drop selection and separation to form a meniscus with an air/ink interface; (d) drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (e) drop separation apparatus, including a power supply adapted to produce an electric field between ink in said nozzles and a print station spaced opposite the nozzles, to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles.
Claim 36
Dependent Claim
136 words
A printer comprising: (a) a plurality of drop-emitter nozzles; (b) a body of ink associated with said nozzles; (c) a pressurizing device adapted to subject ink in said body of ink to a pressure of at least 2% above ambient pressure, at least during drop selection and separation to form a meniscus with an air/ink interface; (d) drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (e) drop separation apparatus, including a power supply adapted to produce an electric field between ink in said nozzles and a print station spaced opposite the nozzles, to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles.
Claim 37
Dependent Claim
103 words
A printing method comprising: (a) providing a body of ink associated with said nozzles; (b) subjecting ink in said body of ink to a pressure of at least 2% above ambient pressure to form a meniscus with an air/ink interface; (c) operating upon the air/ink interface of selected nozzles to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (d) producing an electric field between ink in said nozzles and a print station spaced opposite the nozzles to cause ink from selected nozzles to separate as drops from the body of ink, while retaining ink in non-selected nozzles.
Claim 38
Dependent Claim
103 words
A printing method comprising: (a) providing a body of ink associated with said nozzles; (b) subjecting ink in said body of ink to a pressure of at least 2% above ambient pressure to form a meniscus with an air/ink interface; (c) operating upon the air/ink interface of selected nozzles to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (d) producing an electric field between ink in said nozzles and a print station spaced opposite the nozzles to cause ink from selected nozzles to separate as drops from the body of ink, while retaining ink in non-selected nozzles.
Claim 39
Dependent Claim
133 words
A printer comprising: (a) a plurality of drop-emitter nozzles; (b) a body of ink associated with said nozzles, said body of ink forming a meniscus with an air/ink interface at each nozzle; (c) drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (d) drop separation apparatus, including a power supply adapted to produce an electric field between ink in said nozzles and a print station spaced opposite the nozzles, to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles, said drop selection apparatus being capable of producing said difference in meniscus position in the absence of said drop separation apparatus.
Claim 40
Dependent Claim
133 words
A printer comprising: (a) a plurality of drop-emitter nozzles; (b) a body of ink associated with said nozzles, said body of ink forming a meniscus with an air/ink interface at each nozzle; (c) drop selection apparatus operable upon the air/ink interface to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (d) drop separation apparatus, including a power supply adapted to produce an electric field between ink in said nozzles and a print station spaced opposite the nozzles, to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles, said drop selection apparatus being capable of producing said difference in meniscus position in the absence of said drop separation apparatus.
Claim 41
Dependent Claim
109 words
A printing method comprising: (a) providing a body of ink associated with said nozzles to form a meniscus with an air/ink interface at each nozzle; (b) selecting predetermined nozzles by operation on its air/link interface to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (c) producing an electric field between ink in said nozzles and a print station spaced opposite the nozzles to cause ink from selected nozzles to separate as drops from the body of ink, while retaining ink in non-selected nozzles, said drop selecting step being capable of producing said difference in meniscus position in the absence of said electric field.
Claim 42
Dependent Claim
109 words
A printing method comprising: (a) providing a body of ink associated with said nozzles to form a meniscus with an air/ink interface at each nozzle; (b) selecting predetermined nozzles by operation on its air/link interface to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (c) producing an electric field between ink in said nozzles and a print station spaced opposite the nozzles to cause ink from selected nozzles to separate as drops from the body of ink, while retaining ink in non-selected nozzles, said drop selecting step being capable of producing said difference in meniscus position in the absence of said electric field.
Claim 43
Dependent Claim
142 words
A printer comprising: (a) a plurality of drop-emitter nozzles; (b) a body of ink associated with said nozzles, said body of ink forming a meniscus with an air/ink interface at each nozzle and said ink exhibiting a surface tension decrease of at least 10 mN/m over a 30° C. temperature range; (c) drop selection apparatus operable upon the air/ink interface to apply a heat pulse of less than about 50 μsec. to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (d) drop separation apparatus, including a power supply adapted to produce an electric field between ink in said nozzles and a print station spaced opposite the nozzles, to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles.
Claim 44
Dependent Claim
142 words
A printer comprising: (a) a plurality of drop-emitter nozzles; (b) a body of ink associated with said nozzles, said body of ink forming a meniscus with an air/ink interface at each nozzle and said ink exhibiting a surface tension decrease of at least 10 mN/m over a 30° C. temperature range; (c) drop selection apparatus operable upon the air/ink interface to apply a heat pulse of less than about 50 μsec. to select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (d) drop separation apparatus, including a power supply adapted to produce an electric field between ink in said nozzles and a print station spaced opposite the nozzles, to cause ink from selected nozzles to separate as drops from the body of ink, while allowing ink to be retained in non-selected nozzles.
Claim 45
Dependent Claim
112 words
A printing method comprising: (a) providing a body of ink associated with said nozzles to form a meniscus with an air/ink interface at each nozzle, said ink exhibiting a surface tension decrease of at least 10 mN/m over a 30° C. temperature range; (b) selecting predetermined nozzles by applying a heat pulse of less than about 50 μsec. to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (c) producing an electric field between ink in said nozzles and a print station spaced opposite the nozzles to cause ink from selected nozzles to separate as drops from the body of ink, while retaining ink in non-selected nozzles.
Claim 46
Dependent Claim
112 words
A printing method comprising: (a) providing a body of ink associated with said nozzles to form a meniscus with an air/ink interface at each nozzle, said ink exhibiting a surface tension decrease of at least 10 mN/m over a 30° C. temperature range; (b) selecting predetermined nozzles by applying a heat pulse of less than about 50 μsec. to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (c) producing an electric field between ink in said nozzles and a print station spaced opposite the nozzles to cause ink from selected nozzles to separate as drops from the body of ink, while retaining ink in non-selected nozzles.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-09-28 | 2002-03-30 | 2002-09-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-09-28 | 2006-03-30 | 2006-09-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-09-28 | 2010-03-30 | 2010-09-29 | $7700.00 | Window Closed / Lapsed |