Electrostatically charged image developing toner and electrostatically charged image developing two-component developer

Patent metadata

Field	Value
Publication number	US-10241432-B2
Application number	US-201715787033-A
Country	US
Kind code	B2
Filing date	Oct 18, 2017
Priority date	Nov 2, 2016
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

An electrostatically charged image developing toner includes a particulate toner matrix containing an external additive on the surface of the particulate toner matrix. The external additive includes silica particles A and silica particles B. The silica particles A have a number average primary-particle diameter in the range of 40 to 100 nm and an average circularity in the range of 0.50 to 0.90, and are surface-modified with silicone oil. The silica particles B have a number average primary-particle diameter of 25 nm or more and smaller than the number average primary-particle diameter of the silica particles A, and are surface-modified with alkylalkoxysilane having a specific structure or silazane.

First claim

What is claimed is:

1. An electrostatically charged image developing toner comprising a particulate toner matrix containing an external additive on the surface of the particulate toner matrix, wherein
the external additive comprises silica particles A and silica particles B,
the silica particles A have a number average primary-particle diameter in the range of 40 to 100 nm and an average circularity in the range of 0.50 to 0.90, and are surface-modified with silicone oil, and
the silica particles B have a number average primary-particle diameter of 36 nm or more and smaller than the number average primary-particle diameter of the silica particles A, and are surface-modified with alkylalkoxysilane having a structure represented by Formula (1) or silazane:
R 1 —Si(OR 2 ) 3   Formula (1)

where R 1 represents a linear alkyl group having 1 or more and 10 or less carbon atoms and has an optional substituent; R 2 represents a methyl or ethyl group.

2. The electrostatically charged image developing toner according to claim 1 ,
wherein the silica particles B are surface-modified with alkylalkoxysilane having a structure represented by Formula (1), and
R 1 in Formula (1) has 4 or more and 8 or less carbon atoms.

3. The electrostatically charged image developing toner according to claim 1 ,
wherein the silica particles B are surface-modified with the silazane, and
the silazane contained is hexamethyldisilazane or hexaethyldisilazane.

4. The electrostatically charged image developing toner according to claim 1 ,
wherein the external additive further comprises titanium oxide nanoparticles having an average aspect ratio in the range of 2 to 15, the average aspect ratio being a ratio of a number average major diameter to a number average minor diameter.

5. The electrostatically charged image developing toner according to claim 4 ,
wherein the titanium oxide nanoparticles have a rutile crystal structure.

6. The electrostatically charged image developing toner according to claim 1 ,
wherein the particulate toner matrix comprises a binder resin containing at least a crystalline resin.

7. The electrostatically charged image developing toner according to claim 1 ,
wherein the silicone oil is dimethylsilicone oil.

8. The electrostatically charged image developing toner according to claim 1 ,
wherein the particulate toner matrix contains an amorphous vinyl resin.

9. The electrostatically charged image developing toner according to claim 6 ,
wherein the crystalline resin contains a crystalline polyester resin.

10. The electrostatically charged image developing toner according to claim 1 , wherein the average circularity of the silica particles A is in the range of 0.50 to 0.83.

11. An electrostatically charged image developing two-component developer, comprising the electrostatically charged image developing toner according to claim 1 and carrier particles.

Assignees

• Konica Minolta Inc

Inventors

• Obara Shinya
• Uchino Satoshi
• Ueda Junya
• Takahashi Takuya

Classifications

• G03G9/08795

  characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants · CPC title

• G03G9/09725

  Silicon-oxides; Silicates · CPC title

• G03G9/0823

  Electric parameters · CPC title

• G03G9/08797 Primary

  characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature · CPC title

• G03G9/08755

  Polyesters · CPC title