# US 8,568,948 B2 · Electrostatic-image-developing toner, electrostatic image developer, method of manufacturing electrostatic-image-developing toner, toner cartridge, process cartridge, method of image formation, and image forming apparatus

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- Number: US 8,568,948 B2
- Document ID: US8568948B2
- Status: Granted
- Kind: B2
- Application number: 12/695,744
- Filed: 2010-01-28
- Published: 2011-02-24
- Granted: 2013-10-29
- Earliest claimed: 2009-08-21
- Assignees: Fuji Xerox Co., Ltd.
- Applicants: Yoshimasa Fujiwara; Masaaki Suwabe
- Inventors: Yoshimasa Fujiwara; Masaaki Suwabe
- Web page: https://patentgrep.com/patent/US8568948B2

## CPC

- G03G 9/0819: {characterised by the dimensions of the particles}
- G03G 9/0804: {whereby the components are brought together in a liquid dispersing medium}
- G03G 9/0806: {whereby chemical synthesis of at least one of the toner components takes place}
- G03G 9/08782: {Waxes}
- G03G 2215/0614: one-component
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An electrostatic image developing toner includes toner particles that contain a binding resin, a coloring agent and a release agent and that have D50 of from about 2.0 μm to about 8.0 μm, D50 standing for a volume-average particle size of the toner particles; and non-colored release agent particles, wherein out of the non-colored release agent particles, those ranging in volume-average particle size of from about 0.8 to about 1.2 times a value of D50 are present in a proportion of about 50 or below per 5,000 of the toner particles.

## Claims

### Claim 1

An electrostatic image developing toner comprising:
toner particles that contain a binding resin, a coloring agent and a release agent and that have D50 of from about 3.4 μm to about 6.8 μm, D50 standing for a volume-average particle size of the toner particles; and
non-colored release agent particles,
wherein
out of the non-colored release agent particles, those ranging in volume-average particle size of from about 0.8 to about 1.2 times a value of D50 are present in a proportion from 4 to 50 per 5,000 of the toner particles.

### Claim 2 (depends on 1)

The electrostatic image developing toner as claimed in claim 1, wherein the release agent has a weight-average molecular weight of from about 500 to about 5,000.

### Claim 3 (depends on 1)

The electrostatic image developing toner as claimed in claim 1, wherein the release agent has a melting temperature of from about 60° C. to about 100° C.

### Claim 4 (depends on 1)

The electrostatic image developing toner as claimed in claim 1, wherein the release agent is a hydrocarbon compound.

### Claim 5 (depends on 1)

The electrostatic image developing toner as claimed in claim 1, wherein the coloring agent is C.I. Pigment Yellow 74.

### Claim 6 (depends on 1)

The electrostatic image developing toner as claimed in claim 1, wherein the coloring agent is C.I. Pigment Red 122.

### Claim 7 (depends on 1)

The electrostatic image developing toner as claimed in claim 1, wherein the coloring agent is C.I. Pigment Blue 15:3.

### Claim 8 (depends on 1)

The electrostatic image developing toner as claimed in claim 1, wherein the binding resin has a weight-average molecular weight of from about 20,000 to about 40,000.

### Claim 9 (depends on 1)

An electrostatic image developer comprising:
the electrostatic image developing toner as claimed in claim 1; and
a carrier.

### Claim 10 (depends on 9)

The electrostatic image developer as claimed in claim 9, wherein the carrier is coated with a coating resin.

### Claim 11 (depends on 10)

The electrostatic image developer as claimed in claim 10, wherein the coating resin is from about 0.1 part by weight to about 10 parts by weight in quantity based on the carrier.

### Claim 12 (depends on 1)

The electrostatic image developing toner as claimed in claim 1, toner particles that contain a binding resin, a coloring agent and a release agent and that have D50 of from about 4.2 μm to about 6.8 μm, wherein:
the release agent has a weight-average molecular weight of from about 500 to about 5,000.

### Claim 13 (depends on 1)

A method of image formation, comprising:
electrostatically charging a photoreceptor;
exposing the electrostatically-charged photoreceptor to form a latent image on the photoreceptor;
developing the latent image to form a developed image;
transferring the developed image to a transfer-receiving material; and
fixing a toner on a fixing substrate by heating,
wherein
the toner is the electrostatic image developing toner as claimed in claim 1.