Aqueous ink, ink cartridge and ink jet recording method

Patent metadata

Field	Value
Publication number	US-9593250-B2
Application number	US-201514749820-A
Country	US
Kind code	B2
Filing date	Jun 25, 2015
Priority date	Jun 30, 2014
Publication date	Mar 14, 2017
Grant date	Mar 14, 2017

Abstract

The invention provides an aqueous ink containing a coloring material, wherein the coloring material is a self-dispersible pigment in which a functional group containing another atomic group and an anionic group such as a carboxylic acid group, a sulfonic acid group, a phosphoric acid group or a phosphonic acid group are bonded to a particle surface of a pigment such as carbon black or an organic pigment, and a standard deviation of an introduced amount of the functional group is 0.0380 or less.

First claim

What is claimed is:

1. An aqueous ink comprising a coloring material, wherein the coloring material is a self-dispersible pigment in which a functional group comprising an anionic group and another atomic group are bonded to a particle surface of the pigment, and a standard deviation of an introduced amount of the functional group is 0.0380 or less.

2. The aqueous ink according to claim 1 , wherein the standard deviation of the introduced amount of the functional group is 0.0330 or less.

3. The aqueous ink according to claim 1 , wherein the introduced amount of the functional group is 0.10 mmol/g or more.

4. The aqueous ink according to claim 1 , wherein the anionic group is at least one selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group and a phosphonic acid group.

5. The aqueous ink according to claim 1 , wherein the pigment is at least one selected from the group consisting of carbon black and an organic pigment.

6. The aqueous ink according to claim 1 , wherein the functional group has a structure represented by —R—(COOM 1 ) n , in which R is another atomic group, M 1 is a hydrogen atom, an alkali metal, ammonium or organic ammonium, and n is an integer of 2 or more.

7. The aqueous ink according to claim 1 , wherein the self-dispersible pigment is produced by bonding a group R 1 in the following general formula (1) to a particle surface of the pigment by radical addition reaction induced by removal of a hydrogen atom from a compound represented by the general formula (1):
HN═N—R 1   (1)

wherein R 1 is a group having at least one of an aliphatic group and an aromatic group and being substituted with at least one anionic group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group and a phosphonic acid group.

8. The aqueous ink according to claim 1 , wherein the self-dispersible pigment is produced by bonding a functional group containing an anionic group to a particle surface of the pigment by radical addition reaction induced by halogen removal from a compound represented by the following general formula (2) by employing a compound represented by the following general formula (3):

wherein R 1 is a halogen atom, R 2 is an aryl or heteroaryl group, R 3 is a hydrogen atom, a nitro, cyano or tosyl group, or a halogen atom, x is an integer of 1 or more, R 4 is at least one linking group selected from the group consisting of alkylene, carbonyl, ester and amide groups, y is 0 or 1, R 5 is at least one anionic group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group and a phosphonic acid group, z is an integer of 1 or more, and x +z is equal to the number of hydrogen atoms that R 2 can have;
(R 7 ) n —N—N—(R 7 ) n   (3)

wherein each R 7 is independently a hydrogen atom or an alkyl group, and each n is independently 1 or 2.

9. The aqueous ink according to claim 1 , wherein the self-dispersible pigment is produced by bonding a functional group containing an anionic group to a particle surface of the pigment by causing at least one treatment agent selected from the group consisting of a compound represented by the general formula (4), a compound represented by the general formula (5) and a compound represented by the general formula (6) to react with the particle surface of the pigment:

wherein R 1 is a group having at least one of an aliphatic group and an aromatic group and being substituted with at least one anionic group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group and a phosphonic acid group, and R 2 is an oxygen atom or NH;

wherein R 3 is a group having at least one of an aliphatic group and an aromatic group and being substituted with at least one anionic group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group and a phosphonic acid group;

wherein R 4 and R 5 are, independently of each other, a group having at least one of an aliphatic group and an aromatic group and being substituted with at least one anionic group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, a phosphoric acid group and a phosphonic acid group.

10. An ink cartridge comprising an ink and an ink storage portion storing the ink, wherein the ink comprises the ink according to claim 1 .

11. An ink jet recording method comprising ejecting an ink from a recording head of an ink jet system to record an image on a recording medium, wherein the ink comprises the ink according to claim 1 .

12. The aqueous ink according to claim 1 , wherein the standard deviation of the introduced amount of the functional group is 0.0000 or more.

13. The aqueous ink according to claim 1 , wherein the standard deviation of the introduced amount of the functional group is 0.0200 or more.

14. The aqueous ink according to claim 1 , wherein the introduced amount of the functional group is 1.00 mmol/g or less.

15. The aqueous ink according to claim 1 , wherein the introduced amount of the functional group is 0.80 mmol/g or less.

16. The aqueous ink according to claim 1 , wherein an average particle size (D 50 ) of the pigment is 60 nm or more and 120 nm or less.

17. The aqueous ink according to claim 1 , wherein an average particle size (D 90 ) of the pigment is 100 nm or more and 300 nm or less.

18. The aqueous ink according to claim 1 , wherein a content (% by mass) of the self-dispersible pigment in the ink is 0.10% by mass or more and 15.00% by mass or less.

19. The aqueous ink according to claim 1 , wherein the anionic group is bonded to the particle surface of the pigment through the another atomic group.

20. The aqueous ink according to claim 1 , wherein a structure of the functional group is —R—(COOM 1 ) n , in which R is the another atomic group, M 1 is a hydrogen atom, an alkali metal, ammonium, or organic ammonium, and n is an integer of 2 or more.

Assignees

• Canon Kk

Inventors

• Mizutani Takakazu
• Suzuki Koichi
• Higashi Ryuji
• Watanabe Taiki

Classifications

• C08K9/04

  Ingredients treated with organic substances {(treated with macromolecular compounds C08K9/08)} · CPC title

• C09C3/006

  Combinations of treatments provided for in groups C09C3/04 - C09C3/12 · CPC title

• C01P2006/19

  Oil-absorption capacity, e.g. DBP values · CPC title

• C09C1/024

  Coating · CPC title

• C09C3/08

  Treatment with low-molecular-weight {non-polymer} organic compounds {(C09C3/006, C09C3/048 take precedence)} · CPC title