Toner, toner stored unit, and image forming apparatus

Patent metadata

Field	Value
Publication number	US-10451989-B2
Application number	US-201816119653-A
Country	US
Kind code	B2
Filing date	Aug 31, 2018
Priority date	Mar 3, 2016
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

Provided is a toner including toner base particles and an external additive, wherein each of the toner base particles includes a binder resin, a release agent, and silica, an average abundance ratio (X surf ) of the silica on a region adjacent to a surface of the toner base particle is from 70% through 90%, and a projected area average value S(180) per particle of the toner when the toner is heated to 180° C. and a projected area average value S(30) per particle of the toner when the toner is 30° C. satisfy Formula (1) below,

1.4≤ S (180)/ S (30)≤1.7  Formula (1).

First claim

What is claimed is:

1. A toner comprising:
toner base particles; and
an external additive,
wherein each of the toner base particles includes a binder resin, a release agent, and silica,
an average abundance ratio (X surf ) of the silica on a region adjacent to a surface of the toner base particle is from 70% through 90%, and
a projected area average value S(180) per particle of the toner when the toner is heated to 180° C. and a projected area average value S(30) per particle of the toner when the toner is 30° C. satisfy Formula (1) below,
1.4≤ S (180)/ S (30)≤1.7  Formula (1).

2. The toner according to claim 1 ,
wherein the silica is organosol.

3. The toner according to claim 1 ,
wherein a surface Si amount of the toner base particles measured by XPS is from 10 atomic % through 30 atomic %.

4. The toner according to claim 1 ,
wherein an average primary particle diameter of the silica is from 10 nm through 50 nm where the average primary particle diameter of the silica is detected from a transmission electron microscope (TEM) photograph of a cracked surface of the toner base particle.

5. The toner according to claim 1 ,
wherein an amount of the release agent extracted with n-hexane is from 5 mg through 30 mg per 1.0 g of the toner.

6. The toner according to claim 1 ,
wherein an average circularity of the toner is from 0.970 through 0.985.

7. The toner according to claim 1 ,
wherein the toner has at least a second peak particle diameter at a particle diameter that is from 1.21 times through 1.31 times the modal diameter in a volume-standard particle size distribution of the toner.

8. A toner stored unit comprising:
a unit; and
the toner according to claim 1 stored in the unit.

9. An image forming apparatus comprising:
an electrostatic latent image bearer;
an electrostatic latent image forming unit configured to form an electrostatic latent image on the electrostatic latent image bearer; and
a developing unit configured to develop the electrostatic latent image formed on the electrostatic latent image bearer to form a visible image, where the developing unit includes a toner,

wherein the toner is the toner according to claim 1 .

Assignees

• Kojima Satoshi
• Takahashi Satoshi
• Moritani Tatsuru
• Aoai Shosuke
• Yamaguchi Tatsuki
• Ricoh Co Ltd

Inventors

• Kojima Satoshi
• Takahashi Satoshi
• Moritani Tatsuru
• Aoai Shosuke
• Yamaguchi Tatsuki

Classifications

• G03G9/08

  with toner particles · CPC title

• G03G9/0819

  characterised by the dimensions of the particles · CPC title

• G03G9/09716

  treated with organic compounds · CPC title

• G03G9/08755

  Polyesters · CPC title

• G03G15/0865

  Arrangements for supplying new developer · CPC title