# US 10,121,042 B2 · Fingerprint detection liquid

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,121,042 B2
- Document ID: US10121042B2
- Status: Granted
- Kind: B2
- Application number: 15/416,193
- Filed: 2017-01-26
- Published: 2018-02-08
- Granted: 2018-11-06
- Earliest claimed: 2016-08-03
- Assignees: Kinsei Matec Co., Ltd.
- Applicants: Kinsei Matec Co., Ltd.
- Inventors: Kokichi Tani; Junya Fujioka
- Web page: https://patentgrep.com/patent/US10121042B2

## CPC

- G06V 40/12: Fingerprints or palmprints
- C08K 3/22: of metals
- C08K 2003/2241: {Titanium dioxide}
- C08K 2003/2275: {Ferroso-ferric oxide (Fe3O4)}
- G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

A fingerprint detection liquid that makes it possible to recover clear fingerprints from wet objects and various other objects without adjustment of concentration and composition. The fingerprint detection liquid includes not only pigment particles and a silicone but also a cationic surfactant and an ionizing liquid that ionizes the cationic surfactant. The cationic surfactant preferably includes octyldimethylethylammonium ethylsulfate.

## Claims

### Claim 1

A fingerprint detection liquid comprising:
pigment particles;
a silicone;
a cationic surfactant; and
an ionizing liquid that ionizes the cationic surfactant.

### Claim 2 (depends on 1)

The fingerprint detection liquid according to claim 1, wherein the cationic surfactant comprises an ionic crystal having an ion represented by formula (1):
wherein R1 and R2 are each an alkyl group of 1 to 12 carbon atoms, and R3 is a moiety comprising at least one selected from the group consisting of an aryl group and an alkyl group of 1 to 10 carbon atoms.

### Claim 3 (depends on 2)

The fingerprint detection liquid according to claim 2, wherein the ionic crystal has the ion represented by formula (1) in which R3 is an alkyl group of 1 to 10 carbon atoms.

### Claim 4 (depends on 2)

The fingerprint detection liquid according to claim 2, wherein the ionic crystal having the ion represented by formula (1) is octyldimethylethylammonium ethylsulfate.

### Claim 5 (depends on 1)

The fingerprint detection liquid according to claim 1, wherein the ionizing liquid comprises water.

### Claim 6 (depends on 1)

The fingerprint detection liquid according to claim 1, wherein the silicone is a polyether-modified silicone represented by formula (2):
wherein R4 is a polyoxyalkylene group represented by formula (3):
—R5—O—(C2H4O)a(C3H6O)bR6, wherein R5 is an alkylene group of 2 to 30 carbon atoms, R6 is a substituent represented by formula (4): —(OC)—R7, wherein R7 is an alkyl group of 1 to 30 carbon atoms, a satisfies 1≤a≤50, b satisfies 1≤b≤50, a and b satisfy 10≤a+b≤100, and m and n satisfy 100≤m≤500 and 1≤n≤40, respectively.

### Claim 7 (depends on 1)

The fingerprint detection liquid according to claim 1, wherein the pigment particles comprise at least one selected from the group consisting of titanium oxide, aluminum oxide, zinc oxide, zirconium oxide, red iron oxide, yellow oxide of iron, black oxide of iron, silica, carbon black, aluminum powder, and copper powder, or any composite thereof.