Claims
- 1. A method of color printing on a printing medium comprising the steps of jetting a first color phase-change ink as a liquid onto an area of a printing medium so that the first ink forms a first, thin, solid, semi-transparent, well-defined ink layer that adheringly covers without appreciably penetrating or distorting said medium area, and then jetting a second color phase-change ink as a liquid onto an exposed surface area of said first ink layer so that the second ink forms a second, thin, solid, semi-transparent well-defined ink layer that adheringly covers said first ink layer surface area whereby the ink layers transmit ambient light which is reflected from said medium back through said ink layers and provide subtractive color printing on said medium area that is characterized by high color density and brightness.
- 2. The method defined in claim 1 and further including the additional step of superimposing one or more additional said ink layers of different colors on said second ink layer.
- 3. The method defined in claim 1 wherein the different color inks are applied to said medium in selected different amounts so that the ink layers on said medium have selected different thicknesses.
- 4. A method of color printing on a printing medium by a jet melt method comprising the steps of
- providing at least first and second phase change subtractive color printing inks, each consisting essentially of a wax-based thermoplastic base material which can exist in solid and liquid phases, and a subtractive color dye which is soluble in the base material in both phases and does not appreciably affect the viscosity of the base material;
- jetting the inks onto the printing medium as successive liquid drops each of which at least partially solidifies prior to the impingement of a succeeding drop, for forming print composed of at least two layers of different colors which are superimposed, each layer with a controlled thickness and a well defined boundary with any adjacent layer so that specular reflection of ambient light occurs in each layer whereby the observed color of the print on said printing medium is a vivid subtractive mixture of the colors of all of said ink layers.
- 5. The method defined in claim 4 including the additional steps of jetting the inks so that said successive liquid drops have different sizes whereby selected ink layers have different thicknesses.
- 6. The method defined in claim 5 including the additional steps of jetting the inks so that each additional ink layer is thinner than the immediately underlying ink layer.
- 7. The method defined in claim 4 including the step of maintaining the inks to be jetted at an elevated temperature, at which the base material has a viscosity of 1 to 50 centipoise.
- 8. The method defined in claim 4 including the additional step of selecting each of said printing inks to have an optical density of from 1 to 3.
- 9. The method defined in claim 4 including the step of selecting the colors of said dyes from the group consisting of cyan, magenta, yellow and black.
RELATED APPLICATIONS
This application is a division of Ser. No. 07/402,028, filed Sep. 1, 1989, now abandoned, which is a continuation of Ser. No. 07/128,462, filed Feb. 9, 1988, now abandoned, which is a continuation of Ser. No. 06/921,345, filed Oct. 20, 1986, now U.S. Pat. No. 4,741,930, which is a division of Ser. No. 06/688,000 filed Dec. 31, 1984, now abandoned.
US Referenced Citations (13)
Foreign Referenced Citations (10)
Number |
Date |
Country |
0021389 |
Jan 1981 |
EPX |
0099682 |
Feb 1984 |
EPX |
47-34588 |
Oct 1972 |
JPX |
1114532 |
Nov 1972 |
JPX |
48-36392 |
Nov 1973 |
JPX |
49-103639 |
Oct 1974 |
JPX |
55-54368 |
Apr 1980 |
JPX |
58-140257 |
Aug 1983 |
JPX |
1-294429 |
Nov 1989 |
JPX |
543393 |
Feb 1942 |
GBX |
Non-Patent Literature Citations (4)
Entry |
The Institute for Graphic Communication, Conference Data For Continuing Education Program, 1981, pp. 1-10 (C. A. Muench et al.), "Tricolor Ink Jet System." |
Teletronix, Inc., technical brochure on TEK 4695 Color Graphics Copier, 1983. |
Advanced Color Technology, technical brochure on ACT-1 Color Copier, undated. |
"British Standard Four-Colour and Three-Colour, Letterpress Process Inks", B. S. 1480; 1949 pp. 2-9, British Standards House, London, England. |
Divisions (2)
|
Number |
Date |
Country |
Parent |
402028 |
Sep 1989 |
|
Parent |
688000 |
Dec 1984 |
|
Continuations (2)
|
Number |
Date |
Country |
Parent |
128462 |
Feb 1988 |
|
Parent |
921345 |
Oct 1986 |
|