EP0264281A2
Expired / Lapsed
EP
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Color-matched printing
Assignee: Xerox Corp
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Filing: 1987-10-15
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Granted: —
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Expires: 2007-10-15
Abstract
Abstract A technique is disclosed for matching a color, applicable for example to printing a color on paper which matches a color on a CRT display. Quantities of toners which will generate the matching color are determined and then a pattern of toners which will approximate those quantities is applied. To determine the quantities, a definition of the original color, such as its RGB coordinates, is converted to coordinates in a linear mixing space, such as CIE coordinates. These coordinates, together with coordinates of the toners, are then used to calculate quantities of toners which will produce a matching color. The calculations match hue, saturation and reflectance so that the matching color appears like the original color, so that characteristics of an original image are preserved. A table containing the area coverages of available toner patterns is used in selecting the toner pattern. A separate pattern for each toner may be selected by comparing the quantity of that toner with the area coverages of its available patterns to find the separate toner pattern which will come closest to that quantity. The selected separate patterns of the toners are then combined to obtain a combined toner pattern, which is then applied.
Inventors
- 👤 Robin D. Myers
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 14:54
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6058; Y; Y10; Y10S; Y10S347/00; Y10S347/90
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
57 words
A method of using coloring agents to match an original color, comprising: performing linear mixing calculations with an original color's linear mixing coordinates; linear mixing coordinates of at least two primary coloring agents, and a least one neutral coloring agent to determine quantities of coloring agents to be used to generate a color approximating the original color.
Claim 2
Independent Claim
57 words
A method of using coloring agents to match an original color, comprising: performing linear mixing calculations with an original color's linear mixing coordinates; linear mixing coordinates of at least two primary coloring agents, and a least one neutral coloring agent to determine quantities of coloring agents to be used to generate a color approximating the original color.
Claim 3
Dependent Claim
47 words
The method of claim 1, in which the step of performing linear mixing calculations comprises performing two-dimensional linear mixing with two-dimensional linear mixing coordinates of the original color and the primary coloring agents to obtain linear mixing coordinates of a hue approximating that of the original color.
Claim 4
Dependent Claim
53 words
The method of claim 1 or 2, in which the step of performing linear mixing calculations further comprises performing two-dimensional linear mixing with linear mixing coordinates of the hue and the neutral coloring agent to determine a neutral coloring agent quantity to adjust the hue to obtain the color approximating the original color.
Claim 5
Dependent Claim
37 words
The method of claim 3, in which the substep of performing two-dimensional linear mixing with coordinates of the hue and the neutral coloring agent comprises adjusting the hue's reflectance to be equal to the original color's reflectance.
Claim 6
Dependent Claim
37 words
The method of claim 3, in which the substep of performing two-dimensional linear mixing with coordinates of the hue and the neutral coloring agent comprises adjusting the hue's saturation to be equal to the original color's saturation.
Claim 7
Independent Claim
50 words
The method of any preceding claim, in which the quantities of original coloring agents are quantities of additive RGB coloring agents, the linear mixing color space is the CIE color space, and the substep of using the quantities to find the coordinates comprises converting the RGB quantities into CIE coordinates.
Claim 8
Independent Claim
48 words
The method any preceding claim, in which the step of performing linear mixing calculations comprises using linear mixing coordinates of six primary coloring agents, the six primary coloring agents including three subtractive CMY coloring agents and three subtractive RGB coloring agents generated from the subtractive CMY coloring agents.
Claim 9
Independent Claim
76 words
The method of any preceding claim, in which the coordinates of the primary coloring agents define a polygon, the method further comprising selecting linear mixing coordinates of a point within the polygon, the substep of selecting primary coloring agents comprising selecting two of the primary coloring agents whose coordinates define vertices at ends of a side of the polygon which intersects a line projecting from the center point's coordinates through the original color's linear mixing coordinates.
Claim 10
Independent Claim
68 words
A method of using coloring agents to match an original color, comprising: determining quantities of primary coloring agents to be applied to generate a hue approximating that of an original color; determining a quantity of at least one neutral coloring agent to adjust the hue; and applying a pattern of the coloring agents which approximates the determined coloring agent quantities to obtain a color approximating the original color.
Claim 11
Independent Claim
68 words
A method of using coloring agents to match an original color, comprising: determining quantities of primary coloring agents to be applied to generate a hue approximating that of an original color; determining a quantity of at least one neutral coloring agent to adjust the hue; and applying a pattern of the coloring agents which approximates the determined coloring agent quantities to obtain a color approximating the original color.
Claim 12
Dependent Claim
105 words
The method of claim 9, further comprising: determining quantities of original coloring agents which generate the original color; and determining linear mixing coordinates of the original color based on the quantities of original coloring agents which generate the original color; the step of determining quantities of primary coloring agents comprising using the linear mixing coordinates of the original color and linear mixing coordinates of at least two of the primary coloring agents to be applied; the step of determining the neutral coloring agent quantity comprising using the linear mixing coordinates of the original color and linear mixing coordinates of at least one neutral coloring agent.
Claim 13
Dependent Claim
95 words
Apparatus for using coloring agents to match an original color, comprising: means for determining quantities of coloring agents to be applied to generate a color approximating an original color; and means for applying the coloring agents in a pattern which approximates the determined quantities to obtain a color approximating the original color; the quantities determining means operating to determine quantities of primary coloring agents to be applied to generate a hue approximating that of the original color and further operating to determine a quantity of at least one neutral coloring agent to adjust the hue.
Claim 14
Dependent Claim
95 words
Apparatus for using coloring agents to match an original color, comprising: means for determining quantities of coloring agents to be applied to generate a color approximating an original color; and means for applying the coloring agents in a pattern which approximates the determined quantities to obtain a color approximating the original color; the quantities determining means operating to determine quantities of primary coloring agents to be applied to generate a hue approximating that of the original color and further operating to determine a quantity of at least one neutral coloring agent to adjust the hue.
Claim 15
Dependent Claim
77 words
The apparatus of claim 11, in which the quantities determining means comprises: means for obtaining quantities of original coloring agents which generate the original color; means for determining linear mixing coordinates of the original color from the quantities of original coloring agents; and means for using the linear mixing coordinates of the original color and linear mixing coordinates of at least three of the coloring agents to determine the quantities of the coloring agents to be applied.
References Cited (Backward Citations)
No citation records indexed.
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