EP0409474A2
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EP
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Color image forming apparatus
Assignee: Panasonic Holdings Corp
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Filing: 1990-07-11
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Granted: —
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Expires: 2010-07-11
Abstract
Abstract In order to realize a method of color correction which is capable of performing the UCR compensating for the non-linearity of the superposed densities and the non-linear color correction meeting the non-linearity of the superposed densities at high accuracy with a configuration in substantially the same scale as the conventional linear UCR and linear masking techniques, there is provided a color correction method comprising first conversion means (4, 5, 6) for converting the C, M, Y density information by a monotonously incremental non-linear function with a similarly monotonously incremental derivative, matrix means (7), and second conversion means (8, 9, 10) for converting the same density information by a monotonously incremental non-linear function with a monotonously decremental derivative. In another aspect, there is provided four-color reproduction means comprising first conversion means (104-106; 204-206; 304-306) for converting the C, M, Y information by a monotonously incremental non-linear function with a similarly monotonously incremental derivative, second conversion means (112-115; 212-215; 312-315), for effecting the conversion with a monotonously incremental non-linear function with a monotonously decremental derivative, and black separation means (108; 208, 308), subtraction means and matrix means (107; 207; 307) interposed between the first and second conversion means for controlling the densities of the four inks to implement color recording.
Inventors
- 👤 Haruo Yamashita
- 👤 Hideshi Ishihara
- 👤 Yasuki Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 03:27
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/21; H; H04; H04N; H04N1/00; H04N1/46; H04N1/56; H04N1/60; H04N1/6016; H04N1/6022
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
124 words
A color image forming apparatus comprising first conversion means (4, 5, 6) in which the density information of C, M, Y (cyan, magenta, yellow) obtained by complementary color conversion of the R, G, B (red, green, blue) luminance information is subjected to conversion by a monotonously incremental non-linear function with a monotonously incremental derivative, matrix means (7) supplied with the outputs C1, M1, Y1 of the first conversion means for performing matrix operation and producing C2, M2, Y2, and second conversion means (8, 9, 10) for subjecting the outputs C2, M2, Y2 to conversion by a monotonously incremental non-linear function with a monotonously decremental derivative, wherein the ink density is controlled in accordance with the outputs of the second conversion means for color recording.
Claim 2
Dependent Claim
124 words
A color image forming apparatus comprising first conversion means (4, 5, 6) in which the density information of C, M, Y (cyan, magenta, yellow) obtained by complementary color conversion of the R, G, B (red, green, blue) luminance information is subjected to conversion by a monotonously incremental non-linear function with a monotonously incremental derivative, matrix means (7) supplied with the outputs C1, M1, Y1 of the first conversion means for performing matrix operation and producing C2, M2, Y2, and second conversion means (8, 9, 10) for subjecting the outputs C2, M2, Y2 to conversion by a monotonously incremental non-linear function with a monotonously decremental derivative, wherein the ink density is controlled in accordance with the outputs of the second conversion means for color recording.
Claim 3
Dependent Claim
124 words
A color image forming apparatus comprising first conversion means (304, 305, 306) in which the C, M, Y density information is subjected conversion by a monotonously incremental non-linear function with a monotonously incremental derivative, black separation means (308) for separating the achromatic color information from the outputs C1, M1, Y1, subtraction means (309, 310, 311) for subtracting the outputs of the black separation means form the outputs C1, M1, Y1, and second conversion means (312, 313, 314, 315) for subjecting the outputs of the subtraction means and the black separa tion means to conversion by a monotonously incremental non-linear function with a monotonously decremental derivative, wherein four-color ink densities are controlled in accordance with the outputs of the second conversion means for color recording.
Claim 4
Dependent Claim
124 words
A color image forming apparatus comprising first conversion means (304, 305, 306) in which the C, M, Y density information is subjected conversion by a monotonously incremental non-linear function with a monotonously incremental derivative, black separation means (308) for separating the achromatic color information from the outputs C1, M1, Y1, subtraction means (309, 310, 311) for subtracting the outputs of the black separation means form the outputs C1, M1, Y1, and second conversion means (312, 313, 314, 315) for subjecting the outputs of the subtraction means and the black separa tion means to conversion by a monotonously incremental non-linear function with a monotonously decremental derivative, wherein four-color ink densities are controlled in accordance with the outputs of the second conversion means for color recording.
Claim 5
Dependent Claim
144 words
A color image forming apparatus comprising first conversion means (104, 105, 106) for subjecting the density information C, M, Y to conversion by a monotonously incremental non-linear function with a monotonously incremental derivative, matrix means (107) supplied with the conversion outputs C1, M1, Y1 for effecting matrix operation, black separation means (108) for separating the achromatic color information from the outputs C2, M2, Y2 of the matrix means, subtraction means (109, 110, 111) for subtracting the achromatic color information produced by the black separation means from the outputs C2, M2, Y2, and second conversion means (112, 113, 114, 115) for subjecting the outputs of the subtraction means and the black separation means to conversion by a monotonously incremental non-linear function with a monotonously decremental derivative, wherein four-color ink densities are controlled in accordance with the outputs of the second conversion means for color recording.
Claim 6
Dependent Claim
144 words
A color image forming apparatus comprising first conversion means (104, 105, 106) for subjecting the density information C, M, Y to conversion by a monotonously incremental non-linear function with a monotonously incremental derivative, matrix means (107) supplied with the conversion outputs C1, M1, Y1 for effecting matrix operation, black separation means (108) for separating the achromatic color information from the outputs C2, M2, Y2 of the matrix means, subtraction means (109, 110, 111) for subtracting the achromatic color information produced by the black separation means from the outputs C2, M2, Y2, and second conversion means (112, 113, 114, 115) for subjecting the outputs of the subtraction means and the black separation means to conversion by a monotonously incremental non-linear function with a monotonously decremental derivative, wherein four-color ink densities are controlled in accordance with the outputs of the second conversion means for color recording.
Claim 7
Dependent Claim
146 words
A color image forming apparatus comprising first conversion means (204, 205, 206) for subjecting the density information C, M, Y to conversion with a monotonously incremental non-linear function with a monotonously incremental derivative, black separation means (208) for separating the achromatic color information from the conversion outputs C1, M1, Y1, subtraction means (209, 210, 211) for subtracting the achromatic color information produced by the black separation means from the conversion outputs C1, M1, Y1, matrix means (207) supplied with the outputs C1, M2, Y2 of the subtraction means for effect matrix operation, and second conversion means (212, 213, 214, 215) for subjecting the outputs of the matrix means and the black separation means to conversion by a monotonously incremental non-linear function with a monotonously decremental derivative, wherein the four-color ink densities are controlled in accordance with the outputs of the second conversion means for color recording.
Claim 8
Dependent Claim
146 words
A color image forming apparatus comprising first conversion means (204, 205, 206) for subjecting the density information C, M, Y to conversion with a monotonously incremental non-linear function with a monotonously incremental derivative, black separation means (208) for separating the achromatic color information from the conversion outputs C1, M1, Y1, subtraction means (209, 210, 211) for subtracting the achromatic color information produced by the black separation means from the conversion outputs C1, M1, Y1, matrix means (207) supplied with the outputs C1, M2, Y2 of the subtraction means for effect matrix operation, and second conversion means (212, 213, 214, 215) for subjecting the outputs of the matrix means and the black separation means to conversion by a monotonously incremental non-linear function with a monotonously decremental derivative, wherein the four-color ink densities are controlled in accordance with the outputs of the second conversion means for color recording.
Claim 9
Dependent Claim
58 words
A color image forming apparatus according to Claim 1, 2, 3 or 4, wherein the first conversion means is configured of a non-linear function represented by y = x a , and the second conversion means by y = x 1/a where x is an input, y an output, and a a variable representing the degree of non-linearity.
References Cited (Backward Citations)
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