Ink, image forming method, image forming apparatus, and printed matter

Patent metadata

Field	Value
Publication number	US-11851569-B2
Application number	US-202117209609-A
Country	US
Kind code	B2
Filing date	Mar 23, 2021
Priority date	Mar 31, 2020
Publication date	Dec 26, 2023
Grant date	Dec 26, 2023

Abstract

Provided is an ink including water, an organic solvent, resin particles, a first inorganic pigment, and a second inorganic pigment. The first inorganic pigment comprises particulate titanium oxide. The second inorganic pigment comprises at least one selected from the group consisting of acicular titanium oxide, fusiform titanium oxide, and silica particles.

First claim

The invention claimed is:

1. An ink, comprising:
water;
an organic solvent;
resin particles;
a first inorganic pigment; and
a second inorganic pigment,
wherein the first inorganic pigment comprises particulate titanium oxide, and the second inorganic pigment comprises at least one selected from the group consisting of acicular titanium oxide and fusiform titanium oxide,
wherein a mass ratio of an amount of the first inorganic pigment to an amount of the second inorganic pigment is 4 or more but 10 or less,
wherein the particulate titanium oxide has an aspect ratio of lower than 5,
wherein the fusiform titanium oxide has an aspect ratio of 5 or higher but lower than 10,
wherein the acicular titanium oxide has an aspect ratio of 10 or higher, and
wherein the aspect ratio is a ratio of an average major axis length to an average minor axis length.

2. The ink according to claim 1 , wherein the particulate titanium oxide has an aspect ratio of 1 or higher but 3 or lower.

3. The ink according to claim 1 , wherein the second inorganic pigment comprises silica particles.

4. The ink according to claim 3 , wherein the silica particles have a number average primary particle diameter of 20 nm or more but 100 nm or less.

5. The ink according to claim 1 , wherein the resin particles comprise at least one selected from the group consisting of acrylic resin particles and polyurethane resin particles.

6. The ink according to claim 1 , wherein the organic solvent comprises a water-soluble organic solvent, and the water-soluble organic solvent comprises at least one selected from the group consisting of amide compounds represented by General Formula (1) below, alkanediols, and glycol ethers:

where in the General Formula (1), R represents a straight chain or branched alkyl group having from t through 6 carbon atoms.

7. An image forming method, comprising:
applying a stimulus to the ink according to claim 1 to allow the ink to fly, to print an image.

8. An image forming apparatus, comprising:
an ink container containing the ink according to claim 1 ; and
an ink flying unit configured to allow the ink to fly to print an image.

9. A printed matter, comprising:
a print medium; and
a printed layer on the print medium,
wherein the printed layer comprises a resin, a first inorganic pigment, and a second inorganic pigment,
the first inorganic pigment comprises particulate titanium oxide, and the second inorganic pigment comprises at least one selected from the group consisting of acicular titanium oxide and fusiform titanium oxide,
wherein a mass ratio of an amount of the first inorganic pigment to an amount of the second inorganic pigment is 4 or more but 10 or less,
wherein the particulate titanium oxide has an aspect ratio of lower than 5,
wherein the fusiform titanium oxide has an aspect ratio of 5 or higher but lower than 10,
wherein the acicular titanium oxide has an aspect ratio of 10 or higher, and
wherein the aspect ratio is a ratio of an average major axis length to an average minor axis length.

10. The ink according to claim 1 , wherein the second inorganic pigment comprises the acicular titanium oxide.

11. The ink according to claim 1 , wherein the second inorganic pigment comprises the fusiform titanium oxide.

Assignees

• Ricoh Co Ltd

Inventors

• Hirade Tomohiro
• Kudo Masaki
• AKIMA Mio

Classifications

• C09D11/037 Primary

  characterised by the pigment · CPC title

• B41M5/0023

  Digital printing methods characterised by the inks used (inks per se C09D11/00) · CPC title

• C08K3/22

  of metals · CPC title

• C08K3/36

  Silica · CPC title

• C09D11/033

  characterised by the solvent · CPC title