# US 9,753,389 B2 · Liquid developer

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- Number: US 9,753,389 B2
- Document ID: US9753389B2
- Status: Granted
- Kind: B2
- Application number: 14/855,670
- Filed: 2015-09-16
- Published: 2016-03-24
- Granted: 2017-09-05
- Earliest claimed: 2014-09-19
- Assignees: Konica Minolta, Inc.
- Applicants: Konica Minolta, Inc.
- Inventors: Keiko Momotani; Masahiro Anno; Naoki Yoshie
- Web page: https://patentgrep.com/patent/US9753389B2

## CPC

- G03G 9/132: {obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A liquid developer contains an insulating liquid and toner particles dispersed in the insulating liquid. The toner particles have a resin and a coloring agent. The resin contains at least 10 mass % and at most 40 mass % of an aliphatic polyester resin and at least 60 mass % and at most 90 mass % of an aromatic polyester resin. The resin has an acid value not less than 20 mgKOH/g and not more than 100 mgKOH/g. A difference in acid value between the aliphatic polyester resin and the aromatic polyester resin is not less than 0 mgKOH/g and not more than 10 mgKOH/g.

## Claims

### Claim 1

A liquid developer, comprising:
an insulating liquid; and
toner particles dispersed in said insulating liquid,
said toner particles having a resin and a coloring agent,
said resin containing at least 10 mass % and at most 40 mass % of an aliphatic polyester resin and at least 60 mass % and at most 90 mass % of an aromatic polyester resin,
said resin having an acid value not less than 30 mgKOH/g and not more than 100 mgKOH/g, and
a difference in acid value between said aliphatic polyester resin and said aromatic polyester resin being not less than 0 mgKOH/g and not more than 10 mgKOH/g.

### Claim 2 (depends on 1)

The liquid developer according to claim 1, wherein both of said aliphatic polyester resin and said aromatic polyester resin have a first constitutional unit containing three or more carboxyl groups, as a constitutional unit derived from an acid component.

### Claim 3 (depends on 2)

The liquid developer according to claim 2, wherein said first constitutional unit of said aliphatic polyester resin is identical to said first constitutional unit of said aromatic polyester resin.

### Claim 4 (depends on 1)

The liquid developer according to claim 1, wherein said resin contains at least 10 mass % and at most 30 mass % of said aliphatic polyester resin and at least 70 mass % and at most 90 mass % of said aromatic polyester resin.

### Claim 5 (depends on 1)

The liquid developer according to claim 1, wherein said aliphatic polyester resin or said aromatic polyester resin has a first constitutional unit containing three or more carboxyl groups, as a constitutional unit derived from an acid component.