US4217822A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Color printing method
Assignee: Triprint Pty Ltd
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Filing: 1978-08-07
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Granted: 1980-08-19
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Expires: 1998-08-07
Abstract
Abstract An improvement in a half-tone primary color printing method where the black color is approximated by balancing the primary color components of the print and where the printing process involves using three primary color printing passes only, includes the steps of: (a) preparing separated, differentially angled screen images of the primary color and black components of the print; (b) reducing the dot sizes of the screen images corresponding to the respective red, blue and yellow components of the combination plates prior to the combining of each image with its respective black component; (c) preparing combination primary color and black half-tone printing plates using the prepared screened primary color images having reduced dot sizes as the primary color component image of each combination plate; (d) printing the final color image using said plates and primary color inks; and (e) maintaining the density and volume of said inks during said printing process within a range suitable to maintain optimum color density in the final half-tone image despite the reduction of dot sizes of the primary color components of each printing plate. The density of the black component screen image is increased by up to 50% prior to combination with the primary color screen images and thereby enhances the appearance of the half-tone color work and gives the print produced by the method enhanced depth and clarity.
Inventors
- 👤 Donald D. Milligan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:46
CPC Classifications
G; G03; G03F; G03F3/00; G03F3/04; B; B41; B41C; B41C1/00; B41C1/12; B41M; B41M1/00; B41M1/14; B41M1/18
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
213 words
A half-tone primary color printing method where the black color is approximated by balancing the primary color components of the print and where the printing process involves using three primary color printing passes only, comprising the steps of: (a) preparing separated, differentially angled screen images of the primary color and black components of the print; (b) reducing the dot sizes of the screen images corresponding to the respective red, blue and yellow components of the combination plates prior to the combining of each image with its respective black component; (c) preparing combination primary color and black half-tone printing plates using the prepared screened primary color images having reduced dot sizes as the primary color component image of each combination plate; (d) printing the final color image using said plates and primary color inks; and (e) maintaining the density and volume of said inks during said printing process within a range suitable to maintain optimum color density in the final half-tone image despite the reduction of dot sizes of the primary color components of each printing plate; characterised by the improvement comprising increasing the density of the black component screen image by up to 50% prior to combination with said primary color screen images whereby the appearance of the half-tone color work is enhanced.
Claim 2
Dependent Claim
213 words
A half-tone primary color printing method where the black color is approximated by balancing the primary color components of the print and where the printing process involves using three primary color printing passes only, comprising the steps of: (a) preparing separated, differentially angled screen images of the primary color and black components of the print; (b) reducing the dot sizes of the screen images corresponding to the respective red, blue and yellow components of the combination plates prior to the combining of each image with its respective black component; (c) preparing combination primary color and black half-tone printing plates using the prepared screened primary color images having reduced dot sizes as the primary color component image of each combination plate; (d) printing the final color image using said plates and primary color inks; and (e) maintaining the density and volume of said inks during said printing process within a range suitable to maintain optimum color density in the final half-tone image despite the reduction of dot sizes of the primary color components of each printing plate; characterised by the improvement comprising increasing the density of the black component screen image by up to 50% prior to combination with said primary color screen images whereby the appearance of the half-tone color work is enhanced.
Claim 3
Dependent Claim
30 words
The method recited in claim 1, wherein the printing process includes a black line work component, said method resulting in dense black line work in combination with improved half-tone color.
Claim 4
Dependent Claim
50 words
The method recited in claim 1, wherein the said dot size reduction of the primary color screened images is carried out with the range of 8% to 10% for the red screened image; 8% to 12% for the blue screened image and 4% to 6% for the yellow screened image.
Claim 5
Dependent Claim
39 words
The method recited in claim 1, wherein the printing of said final image is carried out using a color balanced rubine red ink, a color balanced process blue ink and a transparent process yellow ink, in that respective order.
Claim 6
Dependent Claim
18 words
The method recited in claim 4, further wherein said balanced process blue ink is a Cyan Concentrated Blue.
Claim 7
Dependent Claim
38 words
The method recited in claim 1, wherein said screened images are made using screen angles of 45° for the red component, 105° for the blue component, 90° for the yellow component and approximately 75°±7.5° for the black component.
Claim 8
Dependent Claim
69 words
The method recited in claim 6, further including the step of using a screen ruling of 150 lines per inch for producing the primary color screened image components of the half-tone plates, and a screen ruling of 133 lines per inch for producing the black screened image components of said plates, whereby a moire pattern in the shadow areas of the final print due to screen clash is avoided.
Claim 9
Dependent Claim
64 words
The method recited in claim 6 using a screen ruling of 133 lines per inch for producing the primary color screened image components of the half-tone plates and a screen ruling of 150 lines per inch for producing the black screened image components of said plates, whereby a moire pattern in the shadow areas of the final print due to screen clash is avoided.
Claim 10
Dependent Claim
71 words
The method recited in claim 6, further including the step of using a screen ruling of 150 lines per inch for producing the red, blue and black screened image components of the half-tone plates, and a screen ruling of 133 lines per inch for producing the yellow screened image components of said plates, whereby a moire pattern in the shadow areas of the final print due to screen clash is avoided.
Claim 11
Dependent Claim
66 words
The method recited in claim 6 using a screen ruling of 133 lines per inch for producing the red, blue and black screened image components of the half-tone plates and a screen ruling of 120 lines per inch for producing the yellow screened image components of said plates, whereby a moire pattern in the shadow areas of the final print due to screen clash is avoided.
Claim 12
Dependent Claim
18 words
The method recited in claim 1 wherein the density of each black component image is increased by 331/3%±10%.
References Cited (Backward Citations)
US3381612A
Cited
US3926117A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-08-19 | 1984-02-18 | 1984-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-08-19 | 1988-02-18 | 1988-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-08-19 | 1992-02-18 | 1992-08-19 | $7700.00 | Window Closed / Lapsed |