# US 2020/0401060 A1 · Toner for developing electrostatic images

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- Number: US 2020/0401060 A1
- Document ID: US20200401060A1
- Status: Published application
- Kind: A1
- Application number: 17/011,167
- Filed: 2020-09-03
- Published: 2020-12-24
- Earliest claimed: 2016-06-30
- Assignees: Zeon Corporation
- Applicants: Zeon Corporation
- Inventors: Takeru Chiba; Sakyo Yagyu
- Web page: https://patentgrep.com/patent/US20200401060A1

## CPC

- G03G 9/09716: {treated with organic compounds}
- G03G 9/09725: {Silicon-oxides; Silicates}
- C08G 77/04: Polysiloxanes
- G03G 9/08: with toner particles
- G03G 9/0827: {characterised by their shape, e.g. degree of sphericity}
- G03G 9/097: Plasticisers; Charge controlling agents
- G03G 9/09733: {Organic compounds (G03G9/08782 takes precedence)}
- G03G 9/0975: {anionic}
- G03G 9/09775: {containing atoms other than carbon, hydrogen or oxygen (G03G9/09741 - G03G9/09766 take precedence)}
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

The toner for developing electrostatic images is less likely to cause toner ejection and is excellent in printing durability. The toner includes colored resin particles and external additives. The external additives includes an external additive A and an external additive B; wherein the external additive A is silica particles being surface-hydrophobized with a specific hydrophobizing agent and having a specific number average particle diameter; and wherein the external additive B is silicone resin particles having a ratio (BS/TS) of a BET specific surface area (BS) to a theoretical specific surface area (TS) in a range of from 3.0 to 30.0, and having a specific number average particle diameter.

## Claims

### Claim 1

A toner for developing electrostatic images, comprising colored resin particles that comprises a binder resin, a colorant and a charge control agent, and external additives,
wherein the external additives contain at least an external additive A and an external additive B;
wherein the external additive A is silica particles being surface-hydrophobized with at least one hydrophobizing agent selected from the group consisting of a hydrophobizing agent containing an amino group, a silane coupling agent and silicone oil, and having a number average particle diameter of from 5 nm to 20 nm;
wherein the external additive B is silicone resin particles having a ratio (BS/TS) of a BET specific surface area (BS), which is measured by a gas adsorption method, to a theoretical specific surface area (TS), which is obtained by calculating from a number average particle diameter measured by scanning electron microscope (SEM) observation on a theoretical calculation formula, in a range of from 3.0 to 30.0, and having a number average particle diameter of from 0.05 μm to 1.00 μm; and
wherein, with respect to 100 parts by mass of the colored resin particles, a content of the external additive A is from 0.1 part by mass to 2.0 parts by mass, and a content of the external additive B is from 0.1 part by mass to 1.0 part by mass.

### Claim 2 (depends on 1)

The toner for developing electrostatic images according to claim 1,
wherein the external additives further contain an external additive C;
wherein the external additive C is silica particles being surface-hydrophobized with at least one hydrophobizing agent selected from the group consisting of a hydrophobizing agent containing an amino group, a silane coupling agent and silicone oil, and having a number average particle diameter of from 31 nm to 200 nm; and
wherein a content of the external additive C is from 0.1 part by mass to 3.0 parts by mass, with respect to 100 parts by mass of the colored resin particles.

### Claim 3 (depends on 1)

The toner for developing electrostatic images according to claim 1, wherein a water adsorption amount of the external additive B is 1.0% by mass or less.

### Claim 4 (depends on 1)

The toner for developing electrostatic images according to claim 1, wherein a form of the external additive B is a spherical form.

### Claim 5 (depends on 2)

The toner for developing electrostatic images according to claim 2, wherein the colored resin particles, the external additive A and the external additive C are positively chargeable, and particles of the toner are positively chargeable.