# US 10,120,295 B2 · Image forming apparatus

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- Number: US 10,120,295 B2
- Document ID: US10120295B2
- Status: Granted
- Kind: B2
- Application number: 15/423,343
- Filed: 2017-02-02
- Published: 2018-01-04
- Granted: 2018-11-06
- Earliest claimed: 2016-07-01
- Assignees: Fuji Xerox Co., Ltd.
- Applicants: Fuji Xerox Co., Ltd.
- Inventors: Naoki Ota; Masataka Kuribayashi; Takafumi Koide; Yusuke Fukuda; Katsuyuki Kitajima; Yasuhisa Morooka
- Web page: https://patentgrep.com/patent/US10120295B2

## CPC

- G03G 9/0821: {characterised by physical parameters (magnetic parameters G03G9/083)}
- G03G 9/08755: {Polyesters}
- G03G 9/08782: {Waxes}
- G03G 9/08795: {characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants}
- G03G 9/08797: {characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature}
- G03G 9/09716: {treated with organic compounds}
- G03G 9/09725: {Silicon-oxides; Silicates}
- G03G 15/6585: {by using non-standard toners, e.g. transparent toner, gloss adding devices}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An image forming apparatus includes a fixing unit that includes a heating and pressurizing member, and fixes the toner image by performing the operation of heating and pressurizing on the toner image on a recording medium twice or more times with the heating and pressurizing member, wherein the toner contains a toner particle which contains a binder resin containing a crystalline polyester resin, a colorant, and a release agent, and an external additive, and satisfies Expression: 2≤tan δP1≤2.5, wherein tan δP1 represents a maximum value of a mechanical loss tangent existing in a range where a complex elastic modulus is from 1×106 Pa to 1×108 Pa, which is measured at an angular frequency of 6.28 rad/sec and a distortion amount of 0.3%.

## Claims

### Claim 1

An image forming apparatus comprising:
an image holding member;
a charge unit that charges a surface of the image holding member;
an electrostatic latent image forming unit that forms an electrostatic latent image on a charged surface of the image holding member;
a developing unit that contains a developer containing toner, and develops the electrostatic latent image formed on the surface of the image holding member with a developer to form a toner image;
a transfer unit that transfers the toner image formed on the surface of the image holding member to a surface of a recording medium; and
a fixing unit that includes a heating and pressurizing member, and fixes the toner image by performing the operation of heating and pressurizing to the toner image on the recording medium twice or more times with the heating and pressurizing member,
wherein the toner contains a toner particle which contains a binder resin containing a crystalline polyester resin, a colorant, and a release agent, and an external additive, and satisfies the following Expression (1):
2≤tan δP1≤2.5 (1)
wherein tan δP1 represents a maximum value of a mechanical loss tangent existing in a range where a complex elastic modulus is from 1×106 Pa to 1×108 Pa, which is measured at an angular frequency of 6.28 rad/sec and a distortion amount of 0.3%.

### Claim 2 (depends on 1)

The image forming apparatus according to claim 1,
wherein the transfer unit is configured to include:
an intermediate transfer member of which the toner image is to be transferred to a surface;
a primary transfer unit that primarily transfers the toner image formed on the surface of the image holding member to the surface of the intermediate transfer member; and
a secondary transfer unit that secondarily transfers the toner image transferred on the surface of the intermediate transfer member to the surface of the recording medium.

### Claim 3 (depends on 1)

The image forming apparatus according to claim 1,
wherein the maximum value (tan δP1) of the mechanical loss tangent of the toner is from 2 to 2.3.

### Claim 4 (depends on 1)

The image forming apparatus according to claim 1,
wherein the toner satisfies the following Expression (2):
2≤tan δP2≤2.3 (2)
wherein tan δP2 represents a maximum value of a mechanical loss tangent existing in a range where a complex elastic modulus is from 1×106 Pa to 1×107 Pa, which is measured at an angular frequency of 6.28 rad/sec and a distortion amount of 0.3%.

### Claim 5 (depends on 4)

The image forming apparatus according to claim 4,
wherein the maximum value (tan δP2) of the mechanical loss tangent of the toner is from 2 to 2.2.

### Claim 6 (depends on 1)

The image forming apparatus according to claim 1,
wherein a dynamic complex viscosity (η*−30) of the toner at a temperature of (a melting temperature of the crystalline polyester resin −30° C.) is 3×107 Pa·s or more, and a dynamic complex viscosity (η*−10) of the toner at a temperature of (a melting temperature of the crystalline polyester resin −10° C.) is from 1×106 Pa·s to 5×107 Pa·s.

### Claim 7 (depends on 6)

The image forming apparatus according to claim 6,
wherein the dynamic complex viscosity (η*−10) of the toner at a temperature of (a melting temperature of the crystalline polyester resin −10° C.) is from 2×106 Pa·s to 3×107 Pa·s.

### Claim 8 (depends on 6)

The image forming apparatus according to claim 6,
wherein the dynamic complex viscosity (η*−10) of the toner at a temperature of (a melting temperature of the crystalline polyester resin −10° C.) is from 4×106 Pa·s to 2×107 Pa·s.

### Claim 9 (depends on 6)

The image forming apparatus according to claim 6,
wherein the dynamic complex viscosity (η*−30) of the toner at a temperature of (a melting temperature of the crystalline polyester resin −30° C.) is 1×108 Pa·s or more.

### Claim 10 (depends on 6)

The image forming apparatus according to claim 6,
wherein the dynamic complex viscosity (η*−30) of the toner at a temperature of (a melting temperature of the crystalline polyester resin −30° C.) is 5×108 Pa·s or more.

### Claim 11 (depends on 1)

The image forming apparatus according to claim 1,
wherein the fixing unit performs an operation of heating and pressurizing for fixing, and an operation of heating and pressurizing for controlling glossiness of an image.