Ink, method for producing ink, and inkjet system

Patent metadata

Field	Value
Publication number	US-12359081-B2
Application number	US-202117455952-A
Country	US
Kind code	B2
Filing date	Nov 22, 2021
Priority date	Nov 30, 2020
Publication date	Jul 15, 2025
Grant date	Jul 15, 2025

Abstract

An ink is provided that comprises wafer and a dye having a triazine skeleton. The ink satisfies Expression (1):

y ≤−403 x +3400  Expression (1)
where, in Expression (1), x is pH where x is in a range of from 4 through 8.5 (4≤x≤8.5) and y is electric conductivity (mS/cm).

First claim

The invention claimed is:

1. An ink comprising:
water, and
a dye having a triazine skeleton,
wherein the ink satisfies Expression (1):
y≤− 403 x+ 3400  Expression (1),

where, in Expression (1), x is pH where x is 4≤x≤8.5 and y is electric conductivity (mS/cm), further comprising
organic acid in an amount of from 5 parts by mass through 20 parts by mass based on 100 parts by mass of the ink, and wherein the organic acid is at least one selected from the group consisting of acetic acid, formic acid, and malonic acid.

2. The ink according to claim 1 , wherein the ink has pH of 6 or higher but 8 or lower.

3. The ink according to claim 1 , wherein the ink includes calcium ions in an amount of 50 ppm or less.

4. The ink according to claim 1 , wherein the ink includes a heterocyclic aromatic compound.

5. The ink according to claim 4 , wherein the heterocyclic aromatic compound is a benzotriazole compound.

6. The ink according to claim 1 , wherein pKa of the organic acid is 4.5 or less.

7. A method for producing the ink according to claim 1 , the method comprising
adding the organic acid to ink raw materials satisfying Expression (2) to make the ink satisfy Expression (1):
y≤− 403 x+ 3400  Expression (1); and

y>− 403 x+ 3400  Expression (2),

where, in Expressions (1) and (2), x is pH where x is 4≤x≤8.5 and y is electric conductivity (mS/cm),
wherein the ink raw materials include the water and the dye having a triazine skeleton.

8. The method for producing ink according to claim 7 , wherein the ink raw materials include calcium ions in an amount of 50 ppm or less.

9. The method for producing ink according to claim 7 , wherein the ink raw materials include a heterocyclic aromatic compound.

10. The method for producing ink according to claim 9 , wherein the heterocyclic aromatic compound is a benzotriazole compound.

11. An inkjet system comprising:
an ink storing unit storing the ink according to claim 1 ; and
an inkjet head including a nozzle substrate having an ink repellent layer including a silicone resin, the inkjet head configured to discharge the ink stored in the ink storing unit.

12. The ink according to claim 1 , wherein the ink includes calcium ions in an amount of 7 to 50 ppm.

Assignees

• Matsushita Yuuki
• Ricoh Co Ltd

Inventors

• Matsushita Yuuki

Classifications

• C09D11/037

  characterised by the pigment · CPC title

• C09D11/033

  characterised by the solvent · CPC title

• B41J2/1433

  Structure of nozzle plates · CPC title

• C09D11/38

  characterised by non-macromolecular additives other than solvents, pigments or dyes · CPC title

• B41J2/01

  Ink jet · CPC title