# US 9,519,236 B2 · Reversibly allochroic toner, method of producing the same, toner cartridge, and image forming apparatus

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- Number: US 9,519,236 B2
- Document ID: US9519236B2
- Status: Granted
- Kind: B2
- Application number: 14/452,400
- Filed: 2014-08-05
- Published: 2016-02-11
- Granted: 2016-12-13
- Earliest claimed: 2014-08-05
- Assignees: Toshiba Tec Kabushiki Kaisha
- Applicants: Toshiba Tec Kabushiki Kaisha
- Inventors: Takafumi Hara; Masahiro Ikuta; Tsuyoshi Itou; Yasuhito Noda; Kazuhisa Takeda; Takayasu Aoki
- Web page: https://patentgrep.com/patent/US9519236B2

## CPC

- G03G 9/0928: {Compounds capable to generate colouring agents by chemical reaction}
- G03G 9/0804: {whereby the components are brought together in a liquid dispersing medium}
- G03G 9/0819: {characterised by the dimensions of the particles}
- G03G 9/08755: {Polyesters}
- G03G 9/0926: {characterised by physical or chemical properties}
- G03G 9/1075: {Structural characteristics of the carrier particles, e.g. shape or crystallographic structure}
- G03G 9/1136: {containing silicon atoms}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A reversibly allochroic toner contains a binder resin and a colorant. The colorant reversibly switches between first and second color states in response to temperature changes. The colorant exhibits a hysteresis in a temperature-color state curve thereof in which the following relationships are satisfied. Tr<TL2<TL1<TH1<TH2<Tg TH2≦50° C. 20° C.≦Tr≦30° C. where, TH1 is a temperature at which the colorant starts to change from the first color state to the second color state, TH2 is a temperature at which the colorant completely changes to the second color state, TL1 is a temperature at which the colorant starts to change from the second color state to the first color state, TL2 is a temperature at which the colorant completely changes to the first color state, and Tg is a glass transition temperature of the binder resin.

## Claims

### Claim 1

A reversibly allochroic toner comprising:
a binder resin; and
a colorant,
wherein the colorant reversibly switches between a first color state and a second color state in response to a temperature change, and the colorant exhibits a hysteresis in a temperature-color state curve thereof such that,
when the colorant is in the first color state, and the temperature keeps increasing, when the temperature reaches a temperature TH1 (° C.), the colorant starts to change from the first color state to the second color state, and in a temperature region in which the temperature is equal to or higher than a temperature TH2 (° C.) which is higher than the temperature TH1 (° C.), the colorant completely changes to the second color state,
when the colorant is in the second color state, and the temperature keeps decreasing, when the temperature reaches a temperature TL1 (° C.), the colorant starts to change from the second color state to the first color state, and in a temperature region in which the temperature is equal to or lower than a temperature TL2 (° C.) which is lower than the temperature TL1 (° C.), the colorant completely changes to the first color state, and
the relationship of the following Formulae (1), (2), and (3) is satisfied,
Tr<TL2<TL1<TH1<TH2<Tg Formula (1)
TH2≦50° C. Formula (2)
20° C.≦Tr≦30° C. Formula (3)
where Tg indicates a glass transition temperature (° C.) of the binder resin.

### Claim 2 (depends on 1)

The toner according to claim 1,
wherein the relationship of the following Formula (4) is satisfied,
TH1−TL1≦7° C. Formula (4).

### Claim 3 (depends on 1)

The toner according to claim 1,
wherein the temperature TH2 is lower than 40° C.

### Claim 4 (depends on 1)

The toner according to claim 1,
wherein the temperature Tr is 25° C.

### Claim 5 (depends on 1)

The toner according to claim 1,
wherein the colorant comprises capsules containing a first component which is an electron-donating colorable organic compound, a second component which is an electron-accepting compound, and a third component which is a reaction medium controlling the color reaction between the first component and the second component.

### Claim 6 (depends on 5)

The toner according to claim 5,
wherein the third component is an ester of fatty acid and aliphatic alcohol.

### Claim 7

A method of producing a reversibly allochroic toner, comprising:
preparing a first dispersion of binder resin;
preparing a second dispersion of a colorant, wherein the colorant comprises capsules comprising a first component which is an electron-donating colorable organic compound, a second component which is an electron-accepting compound, and a third component which is a reaction medium controlling the color reaction between the first component and the second component;
adding the first dispersion to the second dispersion to aggregate particles of the binder resin and the colorant to form aggregates; and
heating the aggregates to fuse particles of the binder resin and the colorant,
wherein the colorant reversibly switches between a first color state and a second color state in response to a temperature change, and the colorant exhibits a hysteresis in a temperature-color state curve thereof such that,
when the colorant is in the first color state, and the temperature keeps increasing, when the temperature reaches a temperature TH1 (° C.), the colorant starts to change from the first color state to the second color state, and in a temperature region in which the temperature is equal to or higher than a temperature TH2 (° C.) which is higher than the temperature TH1 (° C.), the colorant completely changes to the second color state,
when the colorant is in the second color state, and the temperature keeps decreasing, when the temperature reaches a temperature TL1 (° C.), the colorant starts to change from the second color state to the first color state, and in a temperature region in which the temperature is equal to or lower than a temperature TL2 (° C.) which is lower than the temperature TL1 (° C.), the colorant completely changes to the first color state, and
the relationship of the following Formulae (1), (2), and (3) is satisfied,
Tr<TL2<TL1<TH1<TH2<Tg Formula (1)
TH2≦50° C. Formula (2)
20° C.≦Tr≦30° C. Formula (3)
where Tg indicates a glass transition temperature (° C.) of the binder resin.

### Claim 8 (depends on 7)

The method according to claim 7,
wherein the resin dispersion is continuously added to the colorant dispersion.

### Claim 9 (depends on 7)

The method according to claim 7,
wherein the relationship of the following Formula (4) is satisfied,
TH1−TL1≦7° C. Formula (4).

### Claim 10 (depends on 7)

The method according to claim 7,
wherein the temperature TH2 is lower than 40° C.

### Claim 11 (depends on 7)

The method according to claim 7,
wherein the temperature Tr is 25° C.

### Claim 12 (depends on 7)

The method according to claim 7,
wherein the third component is an ester of fatty acid and aliphatic alcohol.

### Claim 13

A toner cartridge comprising a toner that includes a binder resin and a colorant,
wherein the colorant reversibly switches between a first color state and a second color state in response to a temperature change, and the colorant exhibits a hysteresis in a temperature-color state curve thereof such that,
when the colorant is in the first color state, and the temperature keeps increasing, when the temperature reaches a temperature TH1 (° C.), the colorant starts to change from the first color state to the second color state, and in a temperature region in which the temperature is equal to or higher than a temperature TH2 (° C.) which is higher than the temperature TH1 (° C.), the colorant completely changes to the second color state,
when the colorant is in the second color state, and the temperature keeps decreasing, when the temperature reaches a temperature TL1 (° C.), the colorant starts to change from the second color state to the first color state, and in a temperature region in which the temperature is equal to or lower than a temperature TL2 (° C.) which is lower than the temperature TL1 (° C.), the colorant completely changes to the first color state, and
the relationship of the following Formulae (1), (2), and (3) is satisfied,
Tr<T2<TL1<TH1<TH2<Tg Formula (1)
TH2≦50° C. Formula (2)
20° C.≦Tr≦30° C. Formula (3)
where Tg indicates a glass transition temperature (° C.) of the binder resin.

### Claim 14 (depends on 13)

The toner cartridge according to claim 13,
wherein the relationship of the following Formula (4) is satisfied,
TH1−TL1≦7° C. Formula (4).

### Claim 15 (depends on 13)

The toner cartridge according to claim 13,
wherein the temperature TH2 is lower than 40° C.

### Claim 16 (depends on 13)

The toner cartridge according to claim 13,
wherein the temperature Tr is 25° C.

### Claim 17 (depends on 13)

The toner cartridge according to claim 13,
wherein the colorant comprises capsules containing a first component which is an electron-donating colorable organic compound, a second component which is an electron-accepting compound, and a third component which is a reaction medium controlling the color reaction between the first component and the second component.