White inkjet ink

Patent metadata

Field	Value
Publication number	US-9394453-B2
Application number	US-201314892560-A
Country	US
Kind code	B2
Filing date	May 30, 2013
Priority date	May 30, 2013
Publication date	Jul 19, 2016
Grant date	Jul 19, 2016

Abstract

A white inkjet ink includes an anionic surfactant having a molecular weight less than 10,000, a white pigment, a latex particle, and a balance of water. The white pigment has i) a density less than 3 g/cm 3 , and ii) a substantially constant particle size over a predetermined time period. The substantially constant particle size ranges from about 100 nm to about 300 nm.

First claim

What is claimed is:

1. A white inkjet ink, comprising:
an anionic surfactant having a molecular weight less than 10,000;
a white pigment having i) a density less than 3 g/cm 3 , and ii) a substantially constant particle size over a predetermined time period, the substantially constant particle size ranging from about 100 nm to about 300 nm;
a latex particle; and
a balance of water.

2. The white inkjet ink as defined in claim 1 wherein the predetermined time period is at least 3 months at ambient temperature.

3. The white inkjet ink as defined in claim 1 wherein the anionic surfactant is selected from a 50% active alkylphenol ethoxylate-free polymeric dispersant in water and sodium dodecyl sulfate.

4. The white inkjet ink as defined in claim 3 wherein the anionic surfactant is present in an amount up to 20% of an amount of the white pigment.

5. The white inkjet ink as defined in claim 1 wherein the white pigment is present in an amount ranging from about 5 wt % to about 30 wt % of a total wt % of the inkjet ink.

6. The white inkjet ink as defined in claim 1 wherein the white pigment is selected from precipitated calcium carbonate, aluminum silicate, aluminum oxide, a mica pigment coated with titanium dioxide, and combinations thereof.

7. The white inkjet ink as defined in claim 1 wherein an amount of the latex particle ranges from about 2 wt % with respect to white pigment wt % to about 50 wt % with respect to white pigment wt %.

8. The white inkjet ink as defined in claim 1 , further comprising an optical brightener.

9. A method of making a white inkjet ink, the method comprising:
bead milling a slurry including about 25 wt % of a white pigment having a density less than 3 g/cm 3 ;
diluting the slurry to include about 5 wt % of the white pigment;
selecting an anionic surfactant that will interact with the white pigment such that the white pigment exhibits, in the white inkjet ink, a substantially constant particle size over a predetermined time period, the substantially constant particle size ranging from about 100 nm to about 300 nm; and
mixing the diluted slurry with the selected anionic surfactant, a latex particle, and a balance of water.

10. The method as defined in claim 9 wherein the selecting of the anionic surfactant includes selecting the anionic surfactant from a 50% active alkylphenol ethoxylate-free polymeric dispersant in water and sodium dodecyl sulfate.

11. The method as defined in claim 9 , further comprising increasing an opacity of the white inkjet ink by any of:
increasing an amount of the latex particle included in the white inkjet ink; or
introducing an optical brightener into the white inkjet ink.

12. The method as defined in claim 9 wherein bead milling is accomplished at a predetermined speed for a predetermined time to reduce an initial size of the white pigment to the substantially constant particle size.

13. A printing method, comprising:
selecting a white inkjet ink, including:
an anionic surfactant having a molecular weight less than 10,000;
a white pigment having i) a density less than 3 g/cm 3 , and ii) a substantially constant particle size over a predetermined time period, the substantially constant particle size ranging from about 100 nm to about 300 nm;
a latex particle; and
a balance of water; and

thermal inkjet printing the white inkjet ink onto a medium.

14. The printing method as defined in claim 13 wherein the anionic surfactant is sodium dodecyl sulfate, and wherein the printing method further comprises performing the thermal inkjet printing using a jetting condition selected from:
a voltage ranging from about 18 V to about 22 V;
a pulse width ranging from about 1.8 μs to about 2.2 μs;
an energy ranging from about 1.7 μJ to about 2.6 μJ; and
a temperature of about 35° C.

15. The printing method as defined in claim 13 wherein the anionic surfactant is a 50% active alkylphenol ethoxylate-free polymeric dispersant in water, and wherein the printing method further comprises performing the thermal inkjet printing using a jetting condition selected from:
a voltage ranging from about 20 V to about 22 V;
a pulse width ranging from about 1.6 μs to about 2.0 μs;
an energy ranging from about 1.9 μJ to about 2.6 μJ; and
a temperature of about 35° C.

Assignees

• Hewlett Packard Development Co

Inventors

• Ng Hou T
• Tom Howard S

Classifications

• B41J2/2117

  Ejecting white liquids · CPC title

• B41J2/2114

  Ejecting specialized liquids, e.g. transparent or processing liquids (B41J2/211 takes precedence) · CPC title

• C09D121/02

  Latex · CPC title

• C08K2003/265

  Calcium, strontium or barium carbonate · CPC title

• C09D11/106

  containing macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title