Ink jet color printing method
AssigneeHowtek, Inc.
InventorsRobert Howard, Richard R. Helinski, Herbert E. Menhennett
Life of this patent
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Abstract
Color printing characterized by high color density and color contrast is provided by jetting an ink composition composed of an optically clear, phase change base material and a primary subtractive color dye which is soluble in the base material onto the surface of a printing medium to form a multiplicity of closely spaced color dots or spots arranged to define a line or character on the medium. Each dot consists of one or more well defined, optically clear, semitransparent color layers each of which has a different color so that the observed color of each dot is a true subtractive mixture of the colors in the layers. Specific ink compositions are also disclosed.
Claims8
A method of color printing on a printing medium comprising the steps of
- A. applying a first color phase-change ink as a liquid onto an area of said medium so that the first ink forms a first, thin, solid, semi-transparent, well-defined, optically clear ink layer that adheringly covers without appreciably penetrating or distorting said medium area;
- and
- B. applying a second color phase-change ink as a liquid onto the exposed surface of said first ink layer in superposition therewith so that the second ink forms a second, thin, solid, semi-transparent, well-defined, optically clear ink layer that adheringly covers said first ink layer whereby the ink layers transmit ambient light substantially specularly and produce subtractive color printing on said medium area characterized by high color density and brightness.
Color printed material comprising
- A. a printing medium;
- B. a first thin layer of a phase change primary subtractive color printing ink of a first color adhered to a surface area of the medium, said first layer having a well defined boundary substantially at the medium surface;
- C. one or more additional thin layers of a phase change printing ink, each additional layer having a different primary subtractive color different from said first color superimposed on the first ink layer, each said additional layer having a well defined boundary with any adjacent layer and each of said layers being optically clear and non-turbid so that specular reflection of ambient light occurs in each layer whereby the observed color of the print on said surface area is a vivid subtractive mixture of the colors of all of said ink layers.
Color printed material comprising
- A. a printing medium;
- B. a first thin layer of a phase change primary subtractive color printing ink of a first color adhered to a surface area of the medium, said first layer having a well defined boundary substantially at the medium surface, said phase change ink comprising
- 1. a thermoplastic base material which can exist in solid and liquid phases and which is optically clear in both phases;
- and
- 2. a first primary subtractive color dye which is soluble in the base material in both material phases and does not appreciably affect the viscosity of the base material, said ink composition having a viscosity when the base material is in the liquid phase of from one to fifty centipoise and an optical density of from one to three and being semitransparent when solid;
- and
- C. one or more additional thin layers of a similar phase change printing ink, superimposed on the first ink layer, each additional layer having a primary subtractive dye color different from said first color, each said additional layer also having a well defined boundary with any adjacent layer and all of said layers being optically clear and non-turbid so that specular reflection of ambient light occurs in each layer whereby the observed color of the print on said medium surface area is a vivid subtractive mixture of the colors of all of said ink layers.
Dependencies are inferred from the claim text.