# US 9,753,387 B2 · Toner, developer and developer containing unit

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- Number: US 9,753,387 B2
- Document ID: US9753387B2
- Status: Granted
- Kind: B2
- Application number: 15/152,963
- Filed: 2016-05-12
- Published: 2016-12-01
- Granted: 2017-09-05
- Earliest claimed: 2015-05-27
- Assignees: Ricoh Company, Ltd.
- Applicants: Shin Hasegawa; Tsuyoshi Sugimoto; Hideyuki Santo; Koh Ohnuma; Kohsuke Nagata; Suzuka Karato
- Inventors: Shin Hasegawa; Tsuyoshi Sugimoto; Hideyuki Santo; Koh Ohnuma; Kohsuke Nagata; Suzuka Karato
- Web page: https://patentgrep.com/patent/US9753387B2

## CPC

- G03G 9/08755: {Polyesters}
- G03G 9/0804: {whereby the components are brought together in a liquid dispersing medium}
- G03G 9/0825: {characterised by their structure; characterised by non-homogenuous distribution of components (microcapsular toners G03G9/093)}
- G03G 15/0126: {using a solid developer}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A toner includes a base particle including a polyester resin and a colorant. A sea-island structure is observed by a transmission electron microscope (TEM) in a cross-sectional image of the toner. The island structure includes the colorant and has an average diameter of from 0.2 μm to 1.0 μm, and the number of the island structure is from 5 to 30.

## Claims

### Claim 1

A toner, comprising:
a base particle, comprising:
a polyester resin; and
a colorant,
wherein a sea-island structure is observed by a transmission electron microscope (TEM) in a cross-sectional image of the toner, and wherein the island structure comprises the colorant and has an average diameter of from 0.2 μm to 1.0 μm, and the number of the island structure is from 5 to 30.

### Claim 2 (depends on 1)

The toner of claim 1, wherein the colorant is present within a depth of 1,000 nm in the toner in an amount of from 5% to 50% based on total amount of the colorant.

### Claim 3 (depends on 1)

The toner of claim 1, wherein the number of the island structure is from 10 to 20.

### Claim 4 (depends on 1)

The toner of claim 1, further comprising trivalent aliphatic isocyanate as a tetrahydrofuran-insoluble matter.

### Claim 5 (depends on 1)

The toner of claim 1, further comprising a resin for dispersing colorant, wherein when the resin is dissolved in ethylacetate such that a solid content is 20% by mass, the solution satisfies the following relation:
T(60)%−T(480)%≧30%; and
T(480)%≧50%,
wherein T (60)% and T (480)% are transmittances for light of 500 nm with an optical path length of 1 cm, respectively obtained at time when 60 minutes has passed and at time when 480 min has passed, after the resin is dissolved.

### Claim 6 (depends on 5)

The toner of claim 5, wherein T (60)% is not less than 30%.

### Claim 7 (depends on 1)

The toner of claim 1, wherein the polyester resin has a structure having any one of the following formulae (1) to (3):
R1-(NHCONH—R2)n- (4)
R1-(NHCOO—R2)n- (5)
R1-(OCONH—R2)n- (6)
wherein n represent an integer not less than 3; R1 represents an aromatic or an aliphatic organic group; and R2 represents a group derived from a polyester resin formed at least one of polycarboxylic acid and polyol or an isocyanate-modified polyester resin.

### Claim 8 (depends on 1)

The toner of claim 1, wherein the toner is obtained by a method comprising:
dissolving or dispersing a binder resin in an organic solvent to prepare a solution or a dispersion;
dispersing or emulsifying the solution or the dispersion in an aqueous medium to prepare a dispersion liquid or an emulsified liquid; and
removing the organic solvent from the dispersion liquid or then emulsified liquid.

### Claim 9 (depends on 1)

A developer comprising the toner according to claim 1.

### Claim 10 (depends on 9)

A developer containing unit containing the developer according to claim 9.