# US 7,608,374 B2 · Toner and developer using the toner

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- Number: US 7,608,374 B2
- Document ID: US7608374B2
- Status: Granted
- Kind: B2
- Application number: 11/622,477
- Filed: 2007-01-12
- Published: 2007-07-12
- Granted: 2009-10-27
- Earliest claimed: 2006-01-12
- Assignees: Ricoh Company, Ltd.
- Inventors: Masami Tomita
- Web page: https://patentgrep.com/patent/US7608374B2

## CPC

- G03G 9/0819: {characterised by the dimensions of the particles}
- G03G 9/0808: {by dry mixing the toner components in solid or softened state}
- G03G 9/081: {by mixing the toner components in a liquefied state; melt kneading; reactive mixing}
- G03G 9/0815: {Post-treatment}
- G03G 9/0817: {Separation; Classifying}
- G03G 9/0821: {characterised by physical parameters (magnetic parameters G03G9/083)}
- 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: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

A toner including a binder resin, and a release agent, wherein the following relationships are satisfied: 2 μm≦D4≦4 μm (a) 0.05 μm≦Dw≦0.3 μm (b) Dw≦0.075×D4 (c) F≦−40×Dw+19 (d) F≦20×Dw+5 (e) wherein D4 is a weight-average particle diameter of the toner, Dw is an average dispersion diameter of the release agent and F is a pulverizability index of the toner.

## Claims

### Claim 1

A toner, comprising:
a binder resin, and
a release agent,
wherein the following relationships are satisfied:
2 μm≦D4≦4 μm (d)
0.05 μm≦Dw≦0.3 μm (e)
Dw≦0.075×D4 (f)
wherein D4 is a weight-average particle diameter of the toner and Dw is an average dispersion diameter of the release agent, and
wherein the following relationships (1) and (2) are satisfied:
F≦−40×Dw+19 (1)
F≦20×Dw+5 (2)
wherein F is the pulverizability index of the toner.

### Claim 2 (depends on 1)

The toner of claim 1, wherein the release agent has a viscosity Gw of from 3 to 10 mm2/s at 100° C., and wherein the following relationship (3) is satisfied:
(Gr/1,000)−5≦Gw≦(Gr/1,000)+2 (3)
wherein Gr is a viscosity (Pa·s) of the binder resin at 130° C.

### Claim 3 (depends on 1)

The toner of claim 1, wherein the release agent comprises a wax having:
a molecular weight distribution comprising a main peak of from 1,000 to 2,500; and
a ratio (Mw/Mn) of a weight-average molecular weight (Mw) thereof to a number-average molecular weight (Mn) thereof of from 1.3 to 1.8.

### Claim 4 (depends on 1)

The toner of claim 1, wherein the release agent comprises carnauba wax.

### Claim 5 (depends on 1)

The toner of claim 1, wherein the release agent is present in an amount of from 1 to 8 parts by weight per 100 parts by weight of the binder resin.

### Claim 6 (depends on 1)

The toner of claim 1, wherein the toner is prepared by a method comprising:
kneading toner constituents comprising the binder resin, the release agent and a colorant to prepare kneaded toner constituents; and
pulverizing the toner constituents.

### Claim 7 (depends on 1)

The toner of claim 1, wherein the toner comprises particulate materials having a particle diameter not greater than 1.0 μm in an amount 10% or less in number.

### Claim 8 (depends on 1)

The toner of claim 1, wherein the toner has a weight-average particle diameter (D4) of from 2.0 to 4.0 μm and a ratio (D4/Dn) thereof to a number-average particle diameter of from 1.00 to 1.40.

### Claim 9 (depends on 1)

A developer comprising a carrier and the toner according to claim 1.

### Claim 10 (depends on 1)

A two-component developer comprising a magnetic carrier and the toner according to claim 1.

### Claim 11 (depends on 1)

An imaging forming method comprising: charging a photoreceptor; irradiating the photoreceptor to form an electrostatic latent image thereon; developing the electrostatic latent image with a toner according to claim 1 to form a toner image on the photoreceptor; transferring the toner image onto a transfer sheet; and fixing the toner image on the transfer sheet.

### Claim 12 (depends on 1)

An image forming apparatus comprising: a charger for charging a photoreceptor; an irradiator for irradiating the photoreceptor to form an electrostatic latent image thereon; an image developer for developing the electrostatic latent image with a toner according to claim 1 to form a toner image on the photoreceptor; a transferer for transferring the toner image onto a transfer sheet; and a fixer for fixing the toner image on the transfer sheet.

### Claim 13 (depends on 1)

A hollow, cylindrical toner bottle for discharging toner stored therein when mounted to an electrophotographic image forming apparatus in a substantially horizontal position and then rotated about an axis of said toner bottle, said toner bottle comprising the toner of claim 1.