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US6068361A
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Method and apparatus for multiple drop error diffusion in a liquid ink printer
Assignee: Xerox Corp
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Filing: 1997-10-30
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Granted: 2000-05-30
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Expires: 2017-10-30
Abstract
Abstract A apparatus and method for multiple drop error diffusion in a liquid ink printing system having a print driver including a multiple drop error diffusion circuit. The print driver controls a liquid ink printhead and includes an error diffusion circuit which generates a drop signal as a function of an error signal and a threshold reference signal. The drop signal causes the liquid ink printhead to deposit a plurality of ink drops within one of a plurality of pixel locations on a recording medium. A method includes producing a print driver, for a color liquid ink printer including determining a number of a plurality output levels as a function of a number of a plurality of input levels where a number of ink drops are assigned to each of the determined number of the plurality of output levels.
Inventors
- 👤 David A. Mantell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:17
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/21; B41J2/2132; B41J2/205; B41J2/2054; H; H04; H04N; H04N1/00; H04N1/40; H04N1/40087
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
201 words
A method of producing a print driver, for a color liquid ink printer, depositing drops of ink on a recording medium in response to an input image, including a plurality of input pixels each having a first number of input levels of optical density, to form an output image including a plurality output pixels, each having a second number of output levels of optical density, comprising: determining the second number of the plurality output levels as a function of the first number of the plurality of input levels; assigning a threshold reference signal to each of determined number of the plurality of output levels; assigning a number of ink drops to each of the determined number of the plurality of output levels wherein a portion of the number of ink drops includes a first volume of ink and a remaining portion of the number of ink drops includes a second volume of ink; generating a signal lookup table including the assigned threshold reference signals and the assigned number of ink drops; and producing a print driver, including an error diffusion circuit, coupled to the signal lookup table, to receive from the signal lookup table one of the assigned threshold reference signals.
Claim 2
Independent Claim
201 words
A method of producing a print driver, for a color liquid ink printer, depositing drops of ink on a recording medium in response to an input image, including a plurality of input pixels each having a first number of input levels of optical density, to form an output image including a plurality output pixels, each having a second number of output levels of optical density, comprising: determining the second number of the plurality output levels as a function of the first number of the plurality of input levels; assigning a threshold reference signal to each of determined number of the plurality of output levels; assigning a number of ink drops to each of the determined number of the plurality of output levels wherein a portion of the number of ink drops includes a first volume of ink and a remaining portion of the number of ink drops includes a second volume of ink; generating a signal lookup table including the assigned threshold reference signals and the assigned number of ink drops; and producing a print driver, including an error diffusion circuit, coupled to the signal lookup table, to receive from the signal lookup table one of the assigned threshold reference signals.
Claim 3
Dependent Claim
44 words
The method of claim 1, wherein said producing step comprises producing the print driver, including the error diffusion circuit, to generate a drop generation signal as a function of the receipt from the signal lookup table of one of the assigned threshold reference signals.
Claim 4
Dependent Claim
33 words
The method of claim 2, comprising an output image including a plurality of color separations, each including a plurality of output pixels, each having a second number of output levels of optical density.
Claim 5
Dependent Claim
36 words
The method of claim 3, wherein said determining step comprises determining the second number of the plurality of output levels for each of the plurality of output pixels of each of the plurality of color separations.
Claim 6
Dependent Claim
45 words
The method of claim 4, wherein said first mentioned assigning step comprises assigning the threshold reference signal to each of the second number of the plurality of output levels for each of the plurality of output pixels of each of the plurality of color separations.
Claim 7
Dependent Claim
36 words
The method of claim 5, wherein the difference between adjacent output levels is different for two of the plurality of color separations of a selected one of the second number of the plurality of output levels.
Claim 8
Dependent Claim
36 words
The method of claim 6, wherein the difference between adjacent output levels is different for each of the plurality of color separations of a selected one of the second number of the plurality of output levels.
Claim 9
Dependent Claim
21 words
The method of claim 7, wherein the plurality of color separations comprise a cyan, a magenta, and a yellow color separation.
Claim 10
Dependent Claim
16 words
The method of claim 8, wherein the plurality of color separations include a black color separation.
Claim 11
Dependent Claim
27 words
The method of claim 1, wherein said assigning step comprises assigning a number of ink drops, each of the ink drops including the same volume of ink.
Claim 12
Dependent Claim
159 words
A color printing system for printing in response to an input image signal, including a plurality of input pixels each having a first number of input levels of optical density, an output image including a plurality of pixel location, comprising: a printhead, to deposit a plurality of ink drops on the recording media to print the image; and a print driver for controlling said printhead, said print driver receiving the input image signal and including an error diffusion circuit generating a drop signal as a function of an error signal and a threshold reference signal for causing said color printhead to deposit a plurality of ink drops within one of a plurality of pixel locations, said drop signal causing said color printhead to deposit a plurality of ink drops such that a portion of the plurality of ink drops includes a first drop volume and a remaining portion of the plurality of ink drops includes a second drop volume.
Claim 13
Dependent Claim
159 words
A color printing system for printing in response to an input image signal, including a plurality of input pixels each having a first number of input levels of optical density, an output image including a plurality of pixel location, comprising: a printhead, to deposit a plurality of ink drops on the recording media to print the image; and a print driver for controlling said printhead, said print driver receiving the input image signal and including an error diffusion circuit generating a drop signal as a function of an error signal and a threshold reference signal for causing said color printhead to deposit a plurality of ink drops within one of a plurality of pixel locations, said drop signal causing said color printhead to deposit a plurality of ink drops such that a portion of the plurality of ink drops includes a first drop volume and a remaining portion of the plurality of ink drops includes a second drop volume.
Claim 14
Dependent Claim
46 words
The color printing system of claim 11, wherein said print driver comprises a signal lookup table, including a plurality of threshold reference signals and a plurality of drop signals, each of said plurality of threshold reference signals associated with one of said plurality of drop signals.
Claim 15
Dependent Claim
53 words
The color printing system of claim 12, wherein said error diffusion circuit comprises a comparison circuit, to compare sum of the input level of one of the plurality of input pixels and an error signal, to one of the plurality of threshold reference signals, to generate one of said plurality of drop signals.
Claim 16
Dependent Claim
24 words
The color printing system of claim 13, wherein the output image comprises a plurality of color separations, each including a plurality of output pixels.
Claim 17
Dependent Claim
59 words
The color printing system of claim 14, wherein said print driver comprises a plurality of output level interval signals including a first plurality of output level interval signals associated with a first one of the plurality of color separations and a second plurality of output level interval signals associated with a second one of the plurality of color separations.
Claim 18
Dependent Claim
39 words
The color printing system of claim 15, wherein one of said first plurality of output level interval signals and one of said second plurality of output level interval signals is associated with one of said plurality of drop signals.
Claim 19
Dependent Claim
43 words
The color printing system of claim 16, wherein said one of said first plurality of output level interval signals and said one of said second plurality of output level interval signals associated with said one of said plurality of drops signals are different.
Claim 20
Dependent Claim
28 words
The color printing system of claim 17, wherein the first one of the plurality of color separations comprises one of a cyan, a magenta, or a yellow separation.
Claim 21
Dependent Claim
19 words
The color printing system of claim 18, wherein the second one of the plurality of color separation comprises black.
Claim 22
Dependent Claim
34 words
The color printing system of claim 18, wherein one of the plurality of color separations comprises a color including a different dye loading than the dye loading of another color of the same hue.
Claim 23
Dependent Claim
24 words
The color printing system of claim 15, wherein said first plurality of threshold reference signals is different than said second plurality of threshold signals.
Claim 24
Dependent Claim
41 words
The color printing system of claim 21, wherein said first plurality of output level interval signals include a first number of output level interval signals which are divisible by a number different than a second number of output level interval signals.
Claim 25
Dependent Claim
33 words
The color printing system of claim 22, wherein first plurality of output level interval signals include a first number of output level interval signals which are divisible only by a single prime number.
Claim 26
Dependent Claim
45 words
The color printing system of claim 12, wherein said drop signal causes said color printhead to deposit a plurality of ink drops within one of the plurality of pixel locations, each of the plurality of ink drops including a drop volume of the same size.
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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) | 2003-05-30 | 2003-11-29 | 2004-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-05-30 | 2007-11-29 | 2008-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-05-30 | 2011-11-29 | 2012-05-30 | $7700.00 | Window Closed / Lapsed |