IP Library › Granted Patent US 12704796
Granted Patent B2
US 12704796 · App. 18/039,908 · Granted Aug 11, 2026

Electrophotographic ink compositions

Inventors: Doron Gurovich (Nes Ziona, IL); Vladislav Kaploun (Nes Ziona, IL); Albert Teishev (Nes Ziona, IL); Emad Masoud (Nes Ziona, IL)
Assignee: Hewlett-Packard Development Company, L.P.
G03G9/1355G03G9/0804G03G15/10
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Quick Facts
Patent No.
US 12704796
App. No.
18/039,908
Granted
Aug 11, 2026
Kind
B2
Abstract

A method of producing a liquid electrophotographic ink composition includes combining a pigment with a charge director in a carrier liquid to produce a pigment dispersion; and combining a thermoplastic resin with the pigment dispersion to produce a liquid electrophotographic ink composition; wherein the charge director comprises a metal salt of a sulfonic acid. A method of printing the liquid electrophotographic ink composition and a printing set comprising the liquid electrophotographic ink composition are also included.

Claims (26)

1 . A method of producing a liquid electrophotographic ink composition, comprising:

combining a pigment with a charge director in a carrier liquid, and grinding the pigment with the charge director to produce a pigment dispersion including a pre-treated pigment therein;

combining a thermoplastic resin with the carrier liquid to produce a thermoplastic resin paste; and

combining the thermoplastic resin paste, the pigment dispersion, a charge adjuvant, and the carrier liquid, and grinding the thermoplastic resin paste, the pigment dispersion, and the charge adjuvant to produce a liquid electrophotographic ink composition;

wherein the charge director consists of a metal salt of a sulfonic acid.

2 . The method according to claim 1 , wherein the pigment dispersion is produced by dissolving the charge director in the carrier liquid to form a charge director solution before combining the pigment with the charge director solution.

3 . The method according to claim 1 , wherein the sulfonic acid is selected from C1 to C30 alkyl sulfonic acids.

4 . The method according to claim 1 , wherein a metal of the metal salt is selected from the group consisting of calcium, barium, sodium and aluminium.

5 . The method according to claim 1 , wherein the charge director is present in an amount of up to 20 mg/g solids of the liquid electrophotographic ink composition.

6 . A method of liquid electrophotographic printing, the method comprising:

combining a charging composition with the liquid electrophotographic ink composition produced according to the method of claim 1 to form a print ready liquid electrophotographic ink composition; and

liquid electrophotographically printing the print ready liquid electrophotographic ink composition;

wherein the charging composition comprises:

a lecithin;

a sulfonic acid amine salt; and

a metal salt of a sulfonic acid.

7 . The method according to claim 6 , wherein the sulfonic acid is selected from C1 to C30 alkyl sulfonic acids.

8 . A liquid electrophotographic printing set, comprising:

the liquid electrophotographic ink composition produced according to the method of claim 1 ; and

a charging composition, comprising:

a lecithin;

a sulfonic acid amine salt; and

a metal salt of a sulfonic acid.

9 . The liquid electrophotographic printing set according to claim 8 , wherein the sulfonic acid is selected from C1 to C30 alkyl sulfonic acids.

10 . The method according to claim 1 , wherein the charge adjuvant is aluminum di-stearate or aluminum tri-stearate.

11 . The method according to claim 1 , wherein the charge adjuvant is a combination of aluminum stearate and aluminum palmitate.