Electrostatic image-developing toner, electrostatic image developer, and toner cartridge

Patent metadata

Field	Value
Publication number	US-9835962-B2
Application number	US-201514629995-A
Country	US
Kind code	B2
Filing date	Feb 24, 2015
Priority date	Sep 19, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

There is provided an electrostatic image-developing toner containing a binder resin, a coloring agent and a release agent having a melting temperature of 85° C. to 120° C., the toner having a sea-island structure involving a sea part containing the binder resin and an island part containing the release agent, wherein a mode value of the distribution of the eccentricity degree B of the release agent-containing island part, represented by the specific formula, is from 0.75 to 1.00 and a skewness of the distribution of the eccentricity degree B is from −1.30 to −0.50.

First claim

What is claimed is:

1. An electrostatic image-developing toner comprising a toner particle which comprises:
a binder resin having a glass transition temperature from 50° C. to 80° C.;
a coloring agent;
a release agent having a melting temperature of 85° C. to 120° C.; and
silica treated with a silicone oil as an external additive,
the toner particle having a core-shell structure consisting of a core part and a shell layer formed by aggregation-coalescence method,
the core part of the toner particle having a sea-island structure including a sea part containing the binder resin and a plurality of island parts containing the release agent, wherein:
a mode value of a distribution of an eccentricity degree B of the plurality of release agent-containing island parts, represented by the following Formula (1), is from 0.75 to 1.00 and a skewness of the distribution of the eccentricity degree B is from −1.30 to −0.50:
Eccentricity degree B= 2 d/D   Formula (1)

in Formula (1), D is an equivalent-circle diameter (μm) of the toner particle in a cross-sectional observation of the toner particle, and d is a distance (μm) from the gravity center of the toner particle to the gravity center of one of the plurality of release agent-containing island parts in the cross-sectional observation of the toner particle;
the toner particle has a shape factor SF1 from 110 to 150; and
the shape factor SF1 is defined as SF1=(ML 2 /A)×(π/4)×100, wherein ML represents the absolute maximum length of the toner particle, and A represents the projected area of the toner particle.

2. The electrostatic image-developing toner as claimed in claim 1 ,
wherein the binder resin is a polyester resin.

3. The electrostatic image-developing toner as claimed in claim 2 ,
wherein an alcohol constituent component of the polyester resin contains an alkylene oxide adduct of bisphenol A.

4. The electrostatic image-developing toner as claimed in claim 1 ,
wherein a content of the binder resin is from 40 mass % to 95 mass % based on the entire toner particle.

5. The electrostatic image-developing toner as claimed in claim 1 ,
wherein a content of the coloring agent is from 1 mass % to 30 mass % based on the entire toner particle.

6. The electrostatic image-developing toner as claimed in claim 1 ,
wherein a melting temperature of the release agent is from 90° C. to 100° C.

7. The electrostatic image-developing toner as claimed in claim 6 ,
wherein the release agent contains a hydrocarbon-based wax.

8. The electrostatic image-developing toner as claimed in claim 1 ,
wherein a content of the release agent is from 1 mass % to 20 mass % based on the entire toner particle.

9. The electrostatic image-developing toner as claimed in claim 1 ,
wherein a content of the external additive is from 0.01 mass % to 5 mass % based on the toner particle.

10. The electrostatic image-developing toner as claimed in claim 1 ,
wherein the toner particle has a volume average particle diameter of from 2 μm to 10 μm.

11. An electrostatic image developer comprising the electrostatic image-developing toner claimed in claim 1 .

12. The electrostatic image developer as claimed in claim 11 , containing a carrier coated with a coating resin.

13. The electrostatic image developer as claimed in claim 12 ,
wherein the coating resin contains an electrically conductive particle.

14. The electrostatic image developer as claimed in claim 13 ,
wherein the electrically conductive particle is carbon black.

15. A toner cartridge storing the electrostatic image-developing toner claimed in claim 1 , which is attached to and detached from an image forming apparatus.

Assignees

• Fuji Xerox Co Ltd

Inventors

• Kamiwaki Satoshi
• Matsumoto Akira
• Murakami Tsuyoshi
• Miura Satoshi
• Sugawara Atsushi
• Nakamura Yukiaki
• Yoshida Kana
• Saito Yutaka
• Takahashi Sakon
• Hashimoto Yasuaki
• Sasaki Koji
• Furuta Tsutomu

Classifications

• G03G9/0825 Primary

  characterised by their structure; characterised by non-homogenuous distribution of components (microcapsular toners G03G9/093) · CPC title

• G03G9/08733

  Polymers of unsaturated polycarboxylic acids · CPC title

• G03G9/0827

  characterised by their shape, e.g. degree of sphericity · CPC title

• G03G9/0918

  Phthalocyanine dyes · CPC title

• G03G9/0819

  characterised by the dimensions of the particles · CPC title