Toner and two-component developer

Patent metadata

Field	Value
Publication number	US-12147191-B2
Application number	US-202117491283-A
Country	US
Kind code	B2
Filing date	Sep 30, 2021
Priority date	Oct 9, 2020
Publication date	Nov 19, 2024
Grant date	Nov 19, 2024

Abstract

The toner includes an external additive adhering to the surface of a toner particle. The external additive contains fine powder in which the surface of a core derived by addition of silica to strontium titanate is hydrophobized with a silane compound, and silica.

First claim

What is claimed is:

1. A toner including an external additive adhering to a surface of a toner particle,
wherein the external additive comprises fine powder and silica, wherein the fine powder comprises a surface of a core hydrophobized with a silane compound, and wherein the core is derived by addition of silica to strontium titanate.

2. The toner according to claim 1 ,
wherein a molar ratio of silicon to titanium Si/Ti in the fine powder is 0.03 or more to less than 1.0.

3. The toner according to claim 1 ,
wherein a coverage with the fine powder on the surface of the toner particle is preferably 2% or more to 10% or less.

4. The toner according to claim 1 ,
wherein a coverage with the silica on the surface of the toner particle is 40% or more, and
wherein a sum of the coverage with the silica and a coverage with the fine powder on the surface of the toner particle is 100% or less.

5. The toner according to claim 1 ,
wherein ratio A is 1.1 or less, the ratio A being a ratio of an adhesion strength of the fine powder to an adhesion strength of the silica as calculated by the following formula (1):
A =(Adhesion strength of the silica)/(Adhesion strength of the fine powder)  (1).

6. The toner according to claim 1 ,
wherein resistance value change of toner D is −10 or more, the resistance value change of toner D being calculated by the following formula (2):
D =( B−C )/( b−c )  (2)

wherein in formula (2), B is a resistance value of the toner (GΩ) when b mass parts of the fine powder is added to 100 mass parts of the toner particles, and C is a resistance value of the toner (GΩ) when c mass parts of the fine powder is added to 100 mass parts of the toner particles.

7. The toner according to claim 1 ,
wherein a mean primary particle diameter of the fine powder is 20 nm or more to 60 nm or less.

8. A developer comprising the toner according to claim 1 and a carrier,
wherein the developer has a current value of 10 μA or less upon application of a voltage of 300 V from an end of a carrier magnetic chain of 1 mm in length to the opposite end.

Assignees

• Sharp Kk

Inventors

• Kano Tadanori
• Yamada Takao
• Maeda Hiroki

Classifications

• G03G9/09716

  treated with organic compounds · CPC title

• G03G9/0825

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

• G03G9/0819

  characterised by the dimensions of the particles · CPC title

• G03G9/0821

  characterised by physical parameters (magnetic parameters G03G9/083) · CPC title

• G03G9/09708

  Inorganic compounds · CPC title