# US 8,465,894 B2 · Red toner for electrostatic image development, developer for electrostatic image development, toner set for electrostatic image development, developer set for electrostatic image development and image forming apparatus

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- Number: US 8,465,894 B2
- Document ID: US8465894B2
- Status: Granted
- Kind: B2
- Application number: 12/563,656
- Filed: 2009-09-21
- Published: 2010-07-22
- Granted: 2013-06-18
- Earliest claimed: 2009-01-22
- Assignees: Fuji Xerox Co., Ltd.
- Applicants: Kiyohiro Yamanaka; Satoshi Yoshida; Masanobu Ninomiya
- Inventors: Kiyohiro Yamanaka; Satoshi Yoshida; Masanobu Ninomiya
- Web page: https://patentgrep.com/patent/US8465894B2

## CPC

- G03G 9/08795: {characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants}
- G03G 9/0821: {characterised by physical parameters (magnetic parameters G03G9/083)}
- G03G 9/08797: {characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature}
- G03G 9/0906: {Organic dyes}
- G03G 9/091: {Azo dyes}
- G03G 9/1131: {Coating methods; Structure of coatings}
- G03G 2215/0602: Developer
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A red toner for electrostatic image development, includes: a binder resin; a coloring agent; and a release agent, wherein the red toner for electrostatic image development satisfies the following formulae: 0.3<ID<1.2 5°<A<35° wherein ID represents an image density when a first image is formed on a recording material with a toner loaded amount of 4.0 g/m2 of the red toner; and A represents a hue angle of the first image expressed by an L*a*b* color coordinate space, provided that a hue angle of 0° is on the a*+ axis and a hue angle of 90° is on the b*+ axis.

## Claims

### Claim 1

A toner set for electrostatic image development, comprising:
a magenta toner;
a yellow toner; and
a red toner,
each containing a binder resin, a coloring agent and a release agent,
wherein
the toner set for electrostatic image development satisfies the following formulae:
0.3<ID<1.2
5°<A<35°
0.2<(ID/IDmy)<0.7
A<Amy
wherein
ID represents an image density when a first image is formed on a recording material with a toner loaded amount of 4.0 g/m2 of the red toner;
A represents a hue angle of the first image expressed by an L*a*b* color coordinate space, provided that a hue angle of 0° is on the a*+axis and a hue angle of 90° is on the b*+axis;
IDmy represents an image density when a second image is formed by the magenta toner and the yellow toner on a recording material with a toner loaded amount of 4.0 g/m2 for each of the magenta toner and the yellow toner; and
Amy represents a hue angle of the second image expressed by the L*a*b* color coordinate space,
the red toner comprises a red pigment selected from the group consisting of C.I. Pigment Red 150, C.I. Pigment Red 221, and C.I. Pigment Red 31;
the magenta toner comprises a magenta pigment selected from the group consisting of C.I. Pigment Red 185, C.I. Pigment Red 238, C.I. Pigment Red 269, and C.I. Pigment Red 122; and
the yellow toner comprises a yellow pigment selected from the group consisting of C.I. Pigment Yellow 74 and C.I. Pigment Yellow 185.

### Claim 2 (depends on 1)

The toner set for electrostatic image development according to claim 1, wherein the binder resin of at least the magenta toner contains a crystalline resin.

### Claim 3

A developer set for electrostatic image development, comprising:
a magenta developer, a yellow developer, and a red developer, respectively containing a magenta toner, a yellow toner and a red toner, and a carrier,
each of the magenta, yellow and red toners containing a binder resin, a coloring agent and a release agent,
wherein
the developer set for electrostatic image development satisfies the following formulae:
0.3<ID<1.2
5°<A<35°
0.2<(ID/IDmy)<0.7
A<Amy
wherein
ID represents an image density when a first image is formed on a recording material with a toner loaded amount of 4.0 g/m2 of the red toner;
A represents a hue angle of the first image expressed by an L*a*b* color coordinate space, provided that a hue angle of 0° is on the a*+axis and a hue angle of 90° is on the b*+axis;
IDmy represents an image density when a second image is formed by the magenta toner and the yellow toner on a recording material with a toner loaded amount of 4.0g/m2 for each of the magenta toner and the yellow toner; and
Amy represents a hue angle of the second image expressed by the L*a*b* color coordinate space,
the red toner comprises a red pigment selected from the group consisting of C.I. Pigment Red 150, C.I. Pigment Red 221, and C.I. Pigment Red 31;
the magenta toner comprises a magenta pigment selected from the group consisting of C.I. Pigment Red 185, C.I. Pigment Red 238, C.I. Pigment Red 269, and C.I. Pigment Red 122; and
the yellow toner comprises a yellow pigment selected from the group consisting of C.I. Pigment Yellow 74 and C.I. Pigment Yellow 185.

### Claim 4 (depends on 1)

The toner set for electrostatic image development according to claim 1, wherein A and Amy satisfy the following formula:
5°<(Amy−A)<35°.

### Claim 5 (depends on 1)

The toner set for electrostatic image development according to claim 1, wherein a content of the coloring agent of the red toner is from 0.5 to 8 wt % based on the entire weight of the red toner.

### Claim 6 (depends on 1)

The toner set for electrostatic image development according to claim 1, wherein the coloring agent of the red toner has a dispersion diameter of from 30 to 500 nm.

### Claim 7 (depends on 1)

The toner set for electrostatic image development according to claim 1, wherein the binder resin of the red toner contains a crystalline resin.

### Claim 8 (depends on 7)

The toner set for electrostatic image development according to claim 7, wherein a content of the crystalline resin in the binder resin of the red toner is from 2 to 20 wt %.

### Claim 9 (depends on 7)

The toner set for electrostatic image development according to claim 7, wherein a melting temperature of the crystalline resin is from 50 to 120° C.

### Claim 10 (depends on 7)

The toner set for electrostatic image development according to claim 7, wherein the crystalline resin is a crystalline polyester resin.

### Claim 11 (depends on 10)

The toner set for electrostatic image development according to claim 10, wherein a weight average molecular weight (Mw) of the crystalline polyester resin is from 5,000 to 100,000.

### Claim 12 (depends on 1)

The toner set for electrostatic image development according to claim 1, wherein the release agent of the red toner has a main maximum endothermic peak at 60 to 120° C. in DSC measured in accordance with ASTM D3418-8.

### Claim 13 (depends on 12)

The toner set for electrostatic image development according to claim 12, wherein an added amount of the release agent of the red toner is from 1 to 15 parts by mass per 100 parts by mass of the binder resin.

### Claim 14 (depends on 3)

An image forming apparatus, comprising:
an image holding member;
a latent image forming unit that forms an electrostatic latent image on a surface of the image holding member;
a developing unit that contains the developer set for electrostatic image development according to claim 3 and develops the electrostatic latent image by using the developer to form a toner image;
a primary transfer unit that primarily transfers the developed toner image onto an intermediate transfer member; and
a secondary transfer unit that secondarily transfers the toner image transferred to the intermediate transfer member, onto a recording material.

### Claim 15 (depends on 14)

The image forming apparatus according to claim 14, wherein a sheet conveying speed of the image forming apparatus is from 220 to 600 mm/sec.

### Claim 16 (depends on 1)

The toner set for electrostatic image development according to claim 1, wherein:
the content of the red pigment is from 0.5 wt % to 4 wt %; and
the content of each of the yellow and the magenta pigments is from 3 wt % to 12 wt %.