# US 7,465,526 B2 · Electrostatic latent image developing toner

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- Number: US 7,465,526 B2
- Document ID: US7465526B2
- Status: Granted
- Kind: B2
- Application number: 11/038,521
- Filed: 2005-01-21
- Published: 2005-08-11
- Granted: 2008-12-16
- Earliest claimed: 2004-02-09
- Assignees: Konica Minolta Business Technologies, Inc.
- Inventors: Yasumitsu Fujino; Noboru Ueda; Seishi Ojima; Mitsutoshi Nakamura; Hideaki Ueda
- Web page: https://patentgrep.com/patent/US7465526B2

## CPC

- G03G 9/09314: {Macromolecular compounds}
- 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 9/09307: {specified by the shell material}
- G03G 9/09335: {Non-macromolecular organic compounds}
- G03G 9/09342: {Inorganic compounds}
- G03G 9/0935: {specified by the core material}
- G03G 9/09357: {Macromolecular compounds}
- G03G 9/09378: {Non-macromolecular organic compounds}
- G03G 9/09385: {Inorganic compounds}
- G03G 9/09392: {Preparation thereof}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An electrostatic latent image developing toner contains toner particles each of which has a shell layer on the surface of a core particle comprising at least a first binder resin having a softening point of less than 100° C., a second binder resin having a softening point of not less than 100° C. and a colorant, being applicable to a low-temperature fixing process, and making it possible to achieve conflict functions, such as a heat-resistant storing property, mechanical strength and charge environmental stability.

## Claims

### Claim 1

An electrostatic latent image developing toner comprising:
toner particles each of which has a shell layer on the surface of a core particle comprising at least a first binder resin having a softening point of less than 100° C., a second binder resin having a softening point of not less than 100° C., was and a colorant, wherein the core particle is formed by allowing at least first binder resin particles, second binder resin particles and colorant particles to aggregate/fusion-adhere to one another, and a process in which the shell layer is formed by allowing shell-layer-forming binder resin particles to adhere/fuse onto the surface of the core particle is carried out;
wherein the shell layer has a multiple layer structure with two or more layers and the constituent resin of the outermost layer has a glass transition point of 55-75° C.

### Claim 2

An electrostatic latent image developing toner comprising:
toner particles each of which has a shell layer on the surface of a core particle comprising at least a first binder resin having a softening point of less than 100° C., a second binder resin having a softening point of not less than 100° C., wax and a colorant, wherein the core particle is formed by allowing at least first binder resin particles, second binder resin particles and colorant particles to aggregate/fusion-adhere to one another, and a process in which the shell layer is formed by allowing shell-layer-forming binder resin particles to adhere/fuse onto the surface of the core particle is carried out;
wherein the shell layer has a multiple layer structure with two or more layers, and the constituent resin of the outermost layer has a glass transition point of 55-75° C. and a softening point of 100-160° C.

### Claim 3 (depends on 2)

The toner of claim 2, wherein each of the first binder resin, the second binder resin and the shell-layer-forming binder resin is independently made from at least one kind of resins selected from the group consisting of a vinyl-based resin, a polyurethane resin, an epoxy resin and a polyester resin.

### Claim 4 (depends on 2)

The toner of claim 2, wherein the toner particles are allowed to contain a wax in not less than one mode selected from the following modes:
(i) a mode in which upon forming core particles, the wax is aggregated/fusion-adhered thereto together with at least the first binder resin fine particles, the second binder resin fine particles and the colorant fine particles;
(ii) a mode in which the wax is contained in the first binder resin fine particles and/or the second binder resin fine particles; and
(iii) a mode in which, when the shell layer has a multiple layer structure with two or more layers, the wax is contained in shell-layer-forming binder resin fine particles other than those in the outermost layer.

### Claim 5 (depends on 2)

The toner of claim 2, wherein the first binder resin has the softening point of 60-95° C.

### Claim 6 (depends on 5)

The toner of claim 5, wherein the second binder resin has the softening point of 100-150° C.

### Claim 7 (depends on 5)

The toner of claim 5, wherein the first binder resin has the softening point of 75-90° C.

### Claim 8 (depends on 5)

The toner of claim 5, wherein the second binder resin has the softening point of 105-130° C.

### Claim 9 (depends on 2)

The toner of claim 2, wherein the second binder resin has the softening point of 100-150° C.

### Claim 10 (depends on 7)

The toner of claim 7, wherein the second binder resin has the softening point of 105-135° C.

### Claim 11 (depends on 2)

The toner of claim 2, wherein the constituent resin has the glass transition point of 60-70° C. and a softening point of 110-140° C.

### Claim 12 (depends on 3)

The toner of claim 3, wherein the first binder resin has the softening point of 60-95° C. and the second binder resin has the softening point of 100-150° C.

### Claim 13 (depends on 2)

The toner of claim 2, wherein the first binder resin has the softening point of 60-95° C. and the second binder resin has the softening point of 100-150° C.

### Claim 14 (depends on 13)

The toner of claim 13, wherein the first binder resin has a glass transition point of 23-43° C. and the second binder resin has a glass transition point of 45-80° C.

### Claim 15 (depends on 14)

The toner of claim 14, wherein the first binder resin has the glass transition point of 25-40° C. and the second binder resin has the glass transition point of 50-70° C.

### Claim 16 (depends on 2)

The toner of claim 2, wherein the first binder resin has a glass transition point of 23-43° C. and the second binder resin has a glass transition point of 45-80° C.