Method and apparatus for controlling lightness in colored inkjet inks by means of a transparent white ink composition

Abstract

A transparent white ink composition is formulated to brighten, lighten and or dilute full-tone primary inkjet colors: cyan; magenta; yellow and black, eliminating the need for ‘light ink’ primary color inks. The transparent white ink is jetted concurrently with reduced amounts of full-tone inks in lighter tonal areas conventionally supported by ‘light ink’ primary inks. Printing ‘light ink’ primary colors using a transparent white ink composition may reduce the number of print channels needed to print all four primary colors and the four ‘light ink’ primary colors. Embodiments of the transparent white ink composition may be solvent- or water-based, drying by evaporation of the carrier fluid. Other embodiments may be radiation-curable ink compositions. An inkjet printer includes print carriage and print head assemblies configured for jetting a primary color ink and the transparent white ink in the same pass in correct proportions to achieve a desired effect.

What is claimed is: 
     
         1 . A method comprising:
 receiving instructions from a page description to deliver a pre-formulated light ink to a substrate;   responsive to receiving the instructions:
 causing an amount of a first ink to be applied onto the substrate; 
 while the first ink remains uncured, causing an amount of a second ink to be applied onto the substrate; 
 wherein the first ink is selected from a group comprising a color ink specified by the page description and a transparent white ink and wherein the second ink comprises the remaining ink in the group after selection of the first ink; 
 wherein application of the first and second inks onto the substrate in their uncured state produces a lightened color ink that replaces the pre-formulated light ink specified by the page description. 
   
     
     
         2 . The method of  claim 1 , wherein causing the first and second ink to be applied on the substrate includes:
 causing an inkjet printer to jet the first and second inks onto the substrate.   
     
     
         3 . The method of  claim 1 , further comprising:
 causing the lightened color ink on the substrate to be cured.   
     
     
         4 . The method of  claim 3 , wherein the first ink and second ink are curable using ultraviolet (UV) light and wherein causing the lightened color ink to be cured includes:
 causing UV light to be applied to lightened color ink on the substrate.   
     
     
         5 . The method of  claim 1 , wherein the first ink comprises the color ink and wherein the second ink comprises the transparent white ink. 
     
     
         6 . The method of  claim 1 , wherein the color ink is a primary color inkjet ink selected from a group consisting of cyan, magenta, yellow and black inkjet inks. 
     
     
         7 . The method of  claim 1 , further comprising:
 selecting the amount of the white ink to lighten the amount the color ink to a lightness equal to that of the pre-formulated light ink specified by the page description.   
     
     
         8 . The method of  claim 1 ,
 wherein the amount of the first ink is applied onto the substrate by a first color channel of a printer; and   wherein the amount of the second ink is applied onto the substrate by a second color channel of the printer;   wherein the first color channel is different than the second color channel.   
     
     
         9 . A system comprising:
 a controller; and   program code, which when executed by the controller, causes the system to:
 receive instructions from a page description to deliver a pre-formulated light ink to a substrate; and 
 responsive to receiving the instructions:
 cause an amount of a first ink to be applied onto the substrate; 
 while the first ink remains uncured, cause an amount of a second ink onto to be applied onto the substrate; 
 wherein the first ink is selected from a group comprising a color ink specified by the page description and a transparent white ink and wherein the second ink comprises the remaining ink in the group after selection of the first ink; 
 wherein causing the first and second inks to be applied onto the substrate in their uncured state causes the first and second inks to blend to form a composite ink that replaces the pre-formulated light ink specified by the page description. 
 
   
     
     
         10 . The system of  claim 9 , wherein causing the first and second inks to be applied onto the substrate includes:
 causing an inkjet printer to jet the first and second inks onto the substrate.   
     
     
         11 . The system of  claim 9 , wherein the program code, when executed by the controller, causes the system to further:
 cause the composite ink to be cured.   
     
     
         12 . The system of  claim 9 , wherein the first ink comprises the color ink and wherein the second ink comprises the transparent white ink. 
     
     
         13 . The system of  claim 9 , wherein the color ink is a primary color inkjet ink selected from a group consisting of cyan, magenta, yellow and black inkjet inks. 
     
     
         14 . The system of  claim 9 , wherein the program code, when executed by the controller, causes the system to further:
 select the amount of the white ink to lighten the amount the color ink to a lightness equal to that of the pre-formulated light ink specified by the page description.   
     
     
         15 . The system of  claim 9 ,
 wherein the amount of the first ink is applied onto the substrate via a first color channel of a printer; and   wherein the amount of the second ink is applied onto the substrate via a second color channel of the printer;   wherein the first color channel is different than the second color channel.   
     
     
         16 . A non-transitory computer readable medium storing program code, which when executed by a computer system, causes the computer system to perform operations comprising:
 receiving instructions from a page description to deliver a pre-formulated light ink to a substrate;   responsive to receiving the instructions:
 causing a color ink and a transparent white ink to be blended on the substrate by causing the color ink and the transparent white ink to be applied onto the substrate in an uncured state; 
 wherein blending the color ink and the transparent white ink on the substrate produces a lightened color ink that replaces the pre-formulated link ink. 
   
     
     
         17 . The non-transitory computer readable medium of  claim 16 , the operations further comprising:
 causing the lightened color ink on the substrate to be cured.   
     
     
         18 . The non-transitory computer readable medium of  claim 16 , wherein causing a color ink and a transparent white ink to be applied onto the substrate includes:
 causing a printer to jet the color ink onto the substrate; and   while the color ink remains uncured, causing the printer to jet the transparent white ink onto the substrate.   
     
     
         19 . The non-transitory computer readable medium of  claim 16 , wherein the color ink is a primary color inkjet ink selected from a group consisting of cyan, magenta, yellow and black inkjet inks. 
     
     
         20 . The non-transitory computer readable medium of  claim 16 , the operations further comprising:
 selecting an amount of the white ink to lighten an amount the color ink to a lightness equal to that of the pre-formulated light ink specified by the page description.