# US 2019/0377276 A1 · Toner

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- Number: US 2019/0377276 A1
- Document ID: US20190377276A1
- Status: Published application
- Kind: A1
- Application number: 16/426,954
- Filed: 2019-05-30
- Published: 2019-12-12
- Earliest claimed: 2018-06-07
- Assignees: KYOCERA Document Solutions Inc.
- Applicants: KYOCERA Document Solutions Inc.
- Inventors: Ryotaro KOMADA
- Web page: https://patentgrep.com/patent/US20190377276A1

## CPC

- G03G 9/09716: {treated with organic compounds}
- G03G 9/08726: {Polymers of unsaturated acids or derivatives thereof}
- G03G 9/08791: {characterised by the presence of specified groups or side chains}
- G03G 9/09725: {Silicon-oxides; Silicates}
- G03G 9/09321: {obtained by reactions only involving carbon-to-carbon unsaturated bonds}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A toner includes toner particles each including a toner mother particle and an external additive adhering to a surface of the toner mother particle. The external additive includes silica particles. The silica particles each include a silica base, a first surface treatment layer covering the silica base, and a second surface treatment layer covering the first surface treatment layer. The first surface treatment layer contains a carboxy-modified silicone oil. The second surface treatment layer contains a specific copolymer including a first repeating unit represented by general formula (I) shown below and a second repeating unit represented by general formula (II) shown below. The silica particles have a non-ring-opened oxazoline group content of at least 1 μmol/g and no greater than 500 μmol/g as measured by gas chromatography-mass spectrometry.

## Claims

### Claim 1

A toner comprising toner particles each including a toner mother particle and an external additive adhering to a surface of the toner mother particle, wherein
the external additive includes silica particles,
the silica particles each include a silica base, a first surface treatment layer covering the silica base, and a second surface treatment layer covering the first surface treatment layer,
the first surface treatment layer contains a carboxy-modified silicone oil,
the second surface treatment layer contains a specific copolymer including a first repeating unit represented by general formula (I) shown below and a second repeating unit represented by general formula (II) shown below, and
the silica particles have a non-ring-opened oxazoline group content of at least 1 μmol/g and no greater than 500 μmol/g as measured by gas chromatography-mass spectrometry,
where in general formula (I), R1 represents a hydrogen atom or an alkyl group having a carbon number of at least 1 and no greater than 10 and optionally substituted with a phenyl group, and
in general formula (II), R2 represents a hydrogen atom or an alkyl group having a carbon number of at least 1 and no greater than 10 and optionally substituted with a phenyl group, and an asterisk represents a site that is bonded to an atom in the carboxy-modified silicone oil.

### Claim 2 (depends on 1)

The toner according to claim 1, wherein
the silica particles are contained in an amount of at least 0.5 parts by mass and no greater than 5 parts by mass relative to 100 parts by mass of the toner mother particles.

### Claim 3 (depends on 1)

The toner according to claim 1, wherein
the silica particles have a non-ring-opened oxazoline group content of at least 20 μmol/g and no greater than 460 μmol/g.

### Claim 4 (depends on 1)

The toner according to claim 1, wherein
the specific copolymer further includes a third repeating unit derived from an alkyl (meth)acrylate.