Electrophotographic ink including pearlescent pigment
According to an example, a resin, a carrier liquid, and a pearlescent pigment may be mixed to form a liquid electrophotographic ink.
1. A liquid electrophotographic ink comprising:
A carrier liquid;
a resin; and
a pearlescent pigment encapsulated by the resin, wherein the pearlescent pigment includes alternating layers of a material with a low refractive index and a material with a high refractive index, wherein the material of the low refractive index is interchanged repeatedly with the material of the high refractive index;
wherein the resin, the carrier liquid, and the pearlescent pigment are not subjected to mechanical deformation.
2. The ink of claim 1 , wherein the resin is selected from the group consisting of ethylene acrylic acid copolymers; methacrylic acid copolymers; ethylene vinyl acetate copolymers; copolymers of ethylene and alkyl ester of methacrylic or acrylic acid; copolymers of ethylene acrylic or methacrylic acid and alkyl ester of methacrylic or acrylic acid; copolymers of acrylic or methacrylic acid and at least one alkyl ester of acrylic or methacrylic acid; ethylene-acrylate terpolymers: ethylene-acrylic esters-maleic anhydride or glycidyl methacrylate terpolymers; ethylene-acrylic acid ionomers; and combinations thereof.
3. The ink of claim 1 , wherein the carrier liquid has a dielectric constant of less than 2.
4. The ink of claim 1 , wherein the ink has from about 1% to about 45% non-volatile solids.
5. A method of forming a liquid electrophotographic ink composition comprising:
admixing a resin, a carrier liquid, and a pearlescent pigment at a temperature above a cloud point for the resin up to about 140° C. to form a paste;
diluting the paste to form a slurry; and
forming a liquid electrophotographic ink with the slurry and a charge director;
wherein the resin, the carrier liquid, and the pearlescent pigment are not subjected to mechanical deformation, wherein a temperature during the method of forming a liquid electrophotographic ink decreases from the temperature above the cloud point for the resin to about 20° C., and wherein the pearlescent pigment includes alternating layers of a material with a low refractive index and a material with a high refractive index that are interchanged repeatedly.
6. The method of claim 5 , wherein the temperature of the method progressively decreases from about 140° C. to about 20° C. prior to the diluting of the paste.
7. The method of claim 5 , wherein the admixing occurs under high shear conditions.
8. The method of claim 7 , wherein the high shear conditions include a temperature of about 30° C. at about 15,000 rpm for about 1 hour.
9. The method of claim 7 , wherein the pearlescent pigment is a metamer.
10. The ink of claim 1 , wherein resin encapsulated pigment has a melting point from about 30° C. to about 150° C.
11. The method of claim 5 , wherein resin encapsulated pigment has a melting point from about 30° C. to about 150° C.