Process for producing dry ink colorants that will reduce metamerism
In accordance with the invention, there is a method of forming a toner. The method can include blending two or more colorants to form a sample toner and forming a sample color specimen including a printed image comprising the sample toner. The method can further include comparing spectral distribution curves of the sample color specimen with that of a target color specimen including a target color and repeating the disclosed steps until acquiring a desired spectral match between the sample toner and the target color.
1. A method of matching a toner to a target color of a different color system comprising:
(a) forming a sample toner comprising one or more primary toners by blending two or more colorants;
(b) forming a sample color specimen comprising a printed image comprising the sample toner;
(c) measuring a spectral distribution curve for the sample color specimen and comparing it to the spectral distribution curve for a specimen of the target color, wherein the target color specimen comprises a different primary toner than the sample toner and is printed and determining a % root mean square difference between the spectral distribution curves, a color difference value ΔE between the sample color specimen and the target color specimen, and a general index of metamerism (GMI); and
(d) repeating steps a-c until the % root mean square difference is about 12% or less and until the GMI is less than about four.
2. The method of claim 1 , further comprising blending two or more primary toners to form a sample secondary toner.
3. The method of claim 1 , wherein the step of forming a sample toner comprises blending two or more primary toners.
4. The method of claim 1 , wherein the % root mean square difference between the spectral distribution curves of the sample color specimen and the target color specimen is less than or equal to about 2%.
5. A method of matching a toner to a target color of a different color system comprising:
(a) forming a sample toner comprising one or more primary toners by blending two or more colorants;
(b) forming a sample color specimen comprising a printed image comprising the sample toner;
(c) measuring a spectral distribution curve for the sample color specimen and comparing it to the spectral distribution curve for a specimen of the target color, wherein the target color specimen comprises a different primary toner than the sample toner and is printed and determining a color difference value ΔE between the sample color specimen and the target color specimen and a general index of metamerism (GMI); and
(d) repeating steps a-c until the GMI is about 4 or less.
6. The method of claim 5 , comprising repeating steps a-c until the general index of metamerism (GMI) is less than about 1.
7. The method of claim 1 , wherein the general index of metamerism (GMI) is determined by a method comprising illuminating the sample color specimen and the target color specimen with a reference illuminant and a test illuminant.
8. The method of claim 7 , wherein the reference illuminant comprises a CIE D 65 illuminant having a correlated color temperature of 6500 K.
9. The method of claim 7 , wherein the test illuminant comprises an Illuminant A having a profile of a black body radiator at 2856 K.
10. The method of claim 1 , further comprising selecting one or more colorants from one or more pigments, dyes, and mixture of pigments and dyes.
11. The method of claim 1 , further comprising selecting one or more colorants from a yellow pigment, an orange pigment, a red pigment, a magenta pigment, a purple pigment, a blue pigment, a cyan pigment, a green pigment, and a black pigment.
12. The method of claim 1 , wherein each of the one or more primary toners comprises at least one of Yellow, Orange, Warm Red, Red 032, Rubin Red, Rhodamine Red, Purple, Violet, Blue 72, Reflex Blue, Process Blue, Green toner, and combinations thereof.
13. The method of claim 1 , wherein the target color specimen comprises a Pantone color standard comprising one or more Pantone primary colorants.
14. The method of claim 1 , wherein the target color specimen comprises one or more colorants of an offset printing, a lithography, a flexography, an inkjet printing, and a dry ink xerographic process.
15. The method of claim 1 , wherein the step of forming a sample toner further comprises adding one or more of a resin, charge additives, and surface additives.
16. The method of claim 1 , further comprising repeating steps a-c until the general index of metamerism (GMI) is about one or less.
17. The method of claim 5 , further comprising blending two or more primary toners to form a sample secondary toner.
18. The method of claim 5 , wherein the general index of metamerism (GMI) is determined by a method comprising illuminating the sample color specimen and the target color specimen with a reference illuminant and a test illuminant,
wherein the reference illuminant comprises a CIE D 65 illuminant having a correlated color temperature of 6500 K, and
wherein the test illuminant comprises an Illuminant A having a profile of a black body radiator at 2856 K.
19. The method of claim 5 , further comprising selecting one or more colorants from one or more pigments, dyes, and mixtures of pigments and dyes, wherein the pigments comprise a yellow pigment, an orange pigment, a red pigment, a magenta pigment, a purple pigment, a blue pigment, a cyan pigment, a green pigment, or a black pigment.
20. The method of claim 5 , wherein each of the one or more primary toners comprises at least one of Yellow, Orange, Warm Red, Red 032, Rubin Red, Rhodamin Red, Purple, Violet, Blue 72, Reflex Blue, Process Blue, Green toner, and combinations thereof.
21. The method of claim 5 , wherein the target color specimen comprises a Pantone color standard comprising one or more Pantone primary colorants.
22. The method of claim 5 , wherein the target color specimen comprises one or more colorants of an offset printing, a lithography, a flexography, an inkjet printing, and a dry ink xerographic process.
23. The method of claim 5 , repeating steps a-c until the % root mean square difference is about 12% or less.
24. A method of matching a toner to a target color of a different color comprising:
(a) forming a sample toner comprising one or more primary toners by blending two or more of a yellow pigment, an orange pigment, a red pigment, a magenta pigment, a purple pigment, a blue pigment, a cyan pigment, a green pigment, and a black pigment;
(b) forming a sample color specimen comprising a printed image comprising the sample toner;
(c) measuring a spectral distribution curve for the sample color specimen and comparing it to the spectral distribution curve for a specimen of the target color, wherein the target color specimen is printed and comprises a Pantone color standard comprising one or more Pantone primary colorants and comprises a different primary toner than the sample toner and;
(d) determining a % root mean square difference between the spectral distribution curves, a color difference value ΔE between the sample color specimen and the target color specimen, and a general index of metamerism (GMI); and
(e) repeating steps ac until the % root mean square difference is less than or equal to about 2% and until the GMI is less than about 1.