US5805178A
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US
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Ink jet halftoning with different ink concentrations
Assignee: Eastman Kodak Co
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Filing: 1996-04-10
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Granted: 1998-09-08
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Expires: 2016-04-10
Abstract
Abstract PCT No. PCT/US96/04781 Sec. 371 Date Dec. 4, 1996 Sec. 102(e) Date Dec. 4, 1996 PCT Filed Apr. 10, 1996 PCT Pub. No. WO96/32812 PCT Pub. Date Oct. 17, 1996Cyan and magenta (and black for CC'MM'YK printing) are halftoned with four levels per pixel by dividing the range of pixel intensities into three equal bands. In the darkest band, a +E,fra 2/3+EE intensity ink drop is always present, and a +E,fra 1/3+EE intensity ink drop is halftoned. The middle band is halftoned between the +E,fra 1/3+EE intensity ink drop and the +E,fra 2/3+EE intensity ink drop. The lightest band is halftoned between no ink drop and the +E,fra 1/3+EE intensity ink drop. The band around +E,fra 1/3+EE pixel intensity is eliminated by maintaining the probability of a +E,fra 1/3+EE intensity ink drop at the pixel location constant for the pixel intensities within the band, and halftoning the remaining pixel locations between no ink drop and a drop of +E,fra 2/3+EE ink intensity. The band around +E,fra 2/3+EE pixel intensity is eliminated by maintaining the probability of a +E,fra 2/3+EE intensity ink drop at the pixel location constant for the pixel intensities within the band, and halftoning the remaining pixel locations between a drop of +E,fra 2/3+EE ink intensity and both +E,fra 1/3+EE ink intensity and +E,fra 2/3+EE ink intensity drops present simultaneously.
Inventors
- 👤 Kia Silverbrook
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 15:43
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40087; B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/21; B41J2/2121; B41J2/2128
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
473 words
A method of halftoning images to be printed using bi-level print mechanisms where two differing concentrations of ink or drop size of one or more color components is to be used, and where one of four combinations of ink drop for said color component may be present at each pixel location, said four combinations being: no ink drop; a drop of the ink color component with lesser ink concentration or drop size; a drop of the ink color component with greater ink concentration or drop size, and a drop of both the ink color component with lesser ink concentration or drop size and the ink color component with greater ink concentration or drop size; said method being characterised by the pixel intensity being divided into three regions: (a) the first region being the pixel intensities lying between the pixel intensity representing the optical density resulting when no ink drop is printed, and the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed, wherein ink drops of said lesser ink intensity are printed when the pixel intensity is greater than a dither value; (b) the second region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed, and the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed, wherein ink drops of said greater ink intensity are printed when the pixel intensity is greater than a dither value, and ink drops of said lesser ink intensity are printed at all other pixel locations where the pixel intensity falls within said second region; and (c) the third region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed, and the pixel intensity representing the optical density resulting when ink drops of both said lesser and said greater ink concentration or drop sizes are printed, wherein ink drops of said lesser ink intensity are printed when the pixel intensity is greater than a dither value, and ink drops of said greater ink intensity are printed at all pixel locations where the pixel intensity falls within said third region, said method being further characterised by: (1) said dither values being scaled so that the minimum dither value is substantially equal to the minimum pixel intensity in the corresponding region, and the maximum dither value is substantially equal to the maximum pixel intensity in said corresponding region; and (2) said dither values being determined by indexing a stored table of dither values with the horizontal and vertical pixel addresses, modulo the dither matrix horizontal and vertical sizes respectively.
Claim 2
Independent Claim
473 words
A method of halftoning images to be printed using bi-level print mechanisms where two differing concentrations of ink or drop size of one or more color components is to be used, and where one of four combinations of ink drop for said color component may be present at each pixel location, said four combinations being: no ink drop; a drop of the ink color component with lesser ink concentration or drop size; a drop of the ink color component with greater ink concentration or drop size, and a drop of both the ink color component with lesser ink concentration or drop size and the ink color component with greater ink concentration or drop size; said method being characterised by the pixel intensity being divided into three regions: (a) the first region being the pixel intensities lying between the pixel intensity representing the optical density resulting when no ink drop is printed, and the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed, wherein ink drops of said lesser ink intensity are printed when the pixel intensity is greater than a dither value; (b) the second region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed, and the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed, wherein ink drops of said greater ink intensity are printed when the pixel intensity is greater than a dither value, and ink drops of said lesser ink intensity are printed at all other pixel locations where the pixel intensity falls within said second region; and (c) the third region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed, and the pixel intensity representing the optical density resulting when ink drops of both said lesser and said greater ink concentration or drop sizes are printed, wherein ink drops of said lesser ink intensity are printed when the pixel intensity is greater than a dither value, and ink drops of said greater ink intensity are printed at all pixel locations where the pixel intensity falls within said third region, said method being further characterised by: (1) said dither values being scaled so that the minimum dither value is substantially equal to the minimum pixel intensity in the corresponding region, and the maximum dither value is substantially equal to the maximum pixel intensity in said corresponding region; and (2) said dither values being determined by indexing a stored table of dither values with the horizontal and vertical pixel addresses, modulo the dither matrix horizontal and vertical sizes respectively.
Claim 3
Dependent Claim
24 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 1 where the ink system used is CC'MM'YK.
Claim 4
Dependent Claim
24 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 1 where the ink system used is CC'MM'YK'.
Claim 5
Dependent Claim
138 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 1, wherein said halftoning method is used in printing devices 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 adapted 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 6
Dependent Claim
135 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 1, wherein said halftoning method is used in printing devices 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 adapted 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 7
Dependent Claim
133 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 1, wherein said halftoning method is used in printing devices 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 select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (d) drop separation apparatus adapted 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 8
Independent Claim
794 words
A method of halftoning images to be printed using bi-level print mechanisms where two differing concentrations of ink or drop size of one or more color components is to be used, and where one of four combinations of ink drop for said color component may be present at each pixel location, said four combinations being: no ink drop; a drop of the ink color component with lesser ink concentration or drop size; a drop of the ink color component with greater ink concentration or drop size, and a drop of both the ink color component with lesser ink concentration or drop size and the ink color component with greater ink concentration or drop size; said method being characterised by the pixel intensity being divided into five regions; (a) the first region being the pixel intensities lying between the pixel intensity representing the optical density resulting when no ink drop is printed, and the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed minus an overlap quantity, wherein ink drops of said lesser ink intensity are printed when the pixel intensity is greater than a dither value; (b) the second region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed minus said overlap quantity, and the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed plus said overlap quantity, wherein ink drops of said lesser ink concentration or drop size are printed in a number of pixel locations in said second region substantially equal to one hundred percent minus three times said overlap quantity, ink drops of said greater ink intensity are printed in remaining pixel locations when the pixel intensity is greater than a dither value, and no ink drop is printed at all other pixel locations where the pixel intensity falls within said second region; (c) the third region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed plus said overlap quantity, and the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed minus said overlap quantity, wherein ink drops of said greater ink intensity are printed when the pixel intensity is greater than a dither value, and ink drops of said lesser ink intensity are printed at all other pixel locations where the pixel intensity falls within said third region; (d) the fourth region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed minus said overlap quantity, and the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed plus said overlap quantity, wherein ink drops of said greater ink concentration or drop size are printed in a number of pixel locations in said second region substantially equal to one hundred percent minus three times said overlap quantity, ink drops of said lesser ink intensity are printed at all other pixel locations where the pixel intensity falls within said fourth region, and ink drops of said greater ink intensity are also printed at said other pixel locations when the pixel intensity is greater than a dither value; and (e) the fifth region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed plus said overlap quantity, and the pixel intensity representing the optical density resulting when ink drops of both said lesser and said greater ink concentration or drop sizes are printed, wherein ink drops of said lesser ink intensity are printed when the pixel intensity is greater than a dither value, and ink drops of said greater ink intensity are printed at all pixel locations where the pixel intensity falls within said fifth region, said method being further characterised by: (1) said dither values being scaled so that the minimum dither value is substantially equal to the minimum pixel intensity in the corresponding region, and the maximum dither value is substantially equal to the maximum pixel intensity in said corresponding region; (2) said dither values being determined by indexing a stored table of dither values with the horizontal and vertical pixel addresses, modulo the dither matrix horizontal and vertical sizes respectively; and (3) said overlap quantity being between one sixtieth and one tenth of the range of pixel intensities.
Claim 9
Independent Claim
794 words
A method of halftoning images to be printed using bi-level print mechanisms where two differing concentrations of ink or drop size of one or more color components is to be used, and where one of four combinations of ink drop for said color component may be present at each pixel location, said four combinations being: no ink drop; a drop of the ink color component with lesser ink concentration or drop size; a drop of the ink color component with greater ink concentration or drop size, and a drop of both the ink color component with lesser ink concentration or drop size and the ink color component with greater ink concentration or drop size; said method being characterised by the pixel intensity being divided into five regions; (a) the first region being the pixel intensities lying between the pixel intensity representing the optical density resulting when no ink drop is printed, and the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed minus an overlap quantity, wherein ink drops of said lesser ink intensity are printed when the pixel intensity is greater than a dither value; (b) the second region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed minus said overlap quantity, and the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed plus said overlap quantity, wherein ink drops of said lesser ink concentration or drop size are printed in a number of pixel locations in said second region substantially equal to one hundred percent minus three times said overlap quantity, ink drops of said greater ink intensity are printed in remaining pixel locations when the pixel intensity is greater than a dither value, and no ink drop is printed at all other pixel locations where the pixel intensity falls within said second region; (c) the third region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said lesser ink concentration or drop size is printed plus said overlap quantity, and the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed minus said overlap quantity, wherein ink drops of said greater ink intensity are printed when the pixel intensity is greater than a dither value, and ink drops of said lesser ink intensity are printed at all other pixel locations where the pixel intensity falls within said third region; (d) the fourth region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed minus said overlap quantity, and the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed plus said overlap quantity, wherein ink drops of said greater ink concentration or drop size are printed in a number of pixel locations in said second region substantially equal to one hundred percent minus three times said overlap quantity, ink drops of said lesser ink intensity are printed at all other pixel locations where the pixel intensity falls within said fourth region, and ink drops of said greater ink intensity are also printed at said other pixel locations when the pixel intensity is greater than a dither value; and (e) the fifth region being the pixel intensities lying between the pixel intensity representing the optical density resulting when an ink drop of said greater ink concentration or drop size is printed plus said overlap quantity, and the pixel intensity representing the optical density resulting when ink drops of both said lesser and said greater ink concentration or drop sizes are printed, wherein ink drops of said lesser ink intensity are printed when the pixel intensity is greater than a dither value, and ink drops of said greater ink intensity are printed at all pixel locations where the pixel intensity falls within said fifth region, said method being further characterised by: (1) said dither values being scaled so that the minimum dither value is substantially equal to the minimum pixel intensity in the corresponding region, and the maximum dither value is substantially equal to the maximum pixel intensity in said corresponding region; (2) said dither values being determined by indexing a stored table of dither values with the horizontal and vertical pixel addresses, modulo the dither matrix horizontal and vertical sizes respectively; and (3) said overlap quantity being between one sixtieth and one tenth of the range of pixel intensities.
Claim 10
Dependent Claim
24 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 7 where the ink system used is CC'MM'YK.
Claim 11
Dependent Claim
24 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 7 where the ink system used is CC'MM'YK'.
Claim 12
Dependent Claim
32 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 7, wherein said halftoning method is used in printing devices operating on the LIFT printing principle.
Claim 13
Dependent Claim
33 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 7, wherein said halftoning method is used in printing devices operating on the Thermal LIFT printing principle.
Claim 14
Dependent Claim
33 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 7, wherein said halftoning method is used in printing devices operating on the Proximity LIFT printing principle.
Claim 15
Dependent Claim
138 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 7, wherein said halftoning method is used in printing devices 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 adapted 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 16
Dependent Claim
135 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 7, wherein said halftoning method is used in printing devices 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 adapted 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 17
Dependent Claim
133 words
A method of halftoning images to be printed using bi-level print mechanisms as claimed in claim 7, wherein said halftoning method is used in printing devices 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 select predetermined nozzles and to generate a difference in meniscus position between ink in selected and non-selected nozzles; and (d) drop separation apparatus adapted 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.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2001-09-07 | 2002-03-09 | 2002-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-09-07 | 2006-03-09 | 2006-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-09-07 | 2010-03-09 | 2010-09-08 | $7700.00 | Window Closed / Lapsed |