# US 8,541,152 B2 · Magnetic toner for single component developer

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- Number: US 8,541,152 B2
- Document ID: US8541152B2
- Status: Granted
- Kind: B2
- Application number: 13/432,669
- Filed: 2012-03-28
- Published: 2012-10-11
- Granted: 2013-09-24
- Earliest claimed: 2011-04-06
- Assignees: KYOCERA Document Solutions Inc.
- Applicants: Akinori Koyama
- Inventors: Akinori Koyama
- Web page: https://patentgrep.com/patent/US8541152B2

## CPC

- G03G 9/0926: {characterised by physical or chemical properties}
- G03G 9/0806: {whereby chemical synthesis of at least one of the toner components takes place}
- G03G 9/083: Magnetic toner particles
- G03G 9/08755: {Polyesters}
- G03G 9/0906: {Organic dyes}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A magnetic toner for a single component developer includes in a polyester resin at least a nigrosine dye that is immiscible with the polyester resin, a nigrosine dye that is miscible with the polyester resin, and a magnetic powder. The nigrosine dye that is immiscible with the polyester resin has an average diameter of 0.2 to 4 μm when dispersed in the polyester resin.

## Claims

### Claim 1

A magnetic toner for a single component developer, the magnetic toner comprising in a polyester resin at least a nigrosine dye that is immiscible with the polyester resin, a nigrosine dye that is miscible with the polyester resin, and a magnetic powder,
the nigrosine dye that is immiscible with the polyester resin having an average diameter of 0.2 to 4 μm when dispersed in the polyester resin.

### Claim 2 (depends on 1)

The magnetic toner for a single component developer according to claim 1, wherein the nigrosine dye that is immiscible with the polyester resin has a weight average molecular weight of 305 to 535 as determined by gel permeation chromatography, and the nigrosine dye that is miscible with the polyester resin has a weight average molecular weight of no greater than 212 as determined by gel permeation chromatography.

### Claim 3 (depends on 1)

The magnetic toner for a single component developer according to claim 1, wherein the content of the nigrosine dye that is immiscible with the polyester resin is 0.1 to 10 parts by mass with respect to 100 parts by mass of the polyester resin.

### Claim 4 (depends on 3)

The magnetic toner for a single component developer according to claim 3, wherein the content of the nigrosine dye that is miscible with the polyester resin is 0.1 to 5 parts by mass with respect to 100 parts by mass of the polyester resin.