Carrier for developer of electrostatic latent image, developer, and image forming apparatus

Patent metadata

Field	Value
Publication number	US-10254674-B2
Application number	US-201715730795-A
Country	US
Kind code	B2
Filing date	Oct 12, 2017
Priority date	Oct 20, 2016
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

Abstract

A carrier for a developer of an electrostatic latent image, the carrier including: core particles having magnetism; and a coating layer coating a surface of each of the core particles, wherein the coating layer includes two or more kinds of inorganic particles, at least one kind of inorganic particles among the two or more kinds of inorganic particles is inorganic particles A having conductivity and a peak particle diameter of from 300 nm through 1,000 nm, and surface roughness of the carrier calculated by Formula 1 below is from 1.10 m 2 /g through 1.90 m 2 /g,

C−F  Formula 1

where C is a BET specific surface area (m 2 /g) of the carrier and F is a BET specific surface area (m 2 /g) of the core particles.

First claim

What is claimed is:

1. A carrier for a developer of an electrostatic latent image, the carrier comprising:
core particles having magnetism; and
a coating layer coating a surface of each of the core particles,
wherein
the coating layer includes two or more kinds of inorganic particles,
at least one kind of inorganic particles among the two or more kinds of inorganic particles is inorganic particles A having conductivity and a peak particle diameter of from 300 nm through 1,000 nm, and
surface roughness of the carrier calculated by Formula 1 below is from 1.10 m 2 /g through 1.90 m 2 /g,
C−F  Formula 1

where C is a BET specific surface area (m 2 /g) of the carrier and F is a BET specific surface area (m 2 /g) of the core particles.

2. The carrier according to claim 1 ,
wherein the surface roughness of the carrier is from 1.10 m 2 /g through 1.80 m 2 /g.

3. The carrier according to claim 1 ,
wherein the surface roughness of the carrier is from 1.30 m 2 /g through 1.80 m 2 /g.

4. The carrier according to claim 1 ,
wherein the BET specific surface area of the carrier is from 1.20 m 2 /g through 2.50 m 2 /g.

5. The carrier according to claim 1 ,
wherein the BET specific surface area of the core particles is from 0.01 m 2 /g through 0.50 m 2 /g.

6. The carrier according to claim 1 ,
wherein a volume average particle diameter of the carrier is from 28 μm through 40 μm.

7. The carrier according to claim 1 ,
wherein a material of the inorganic particles A is a tin oxide compound.

8. The carrier according to claim 7 ,
wherein the tin oxide compound is at least one selected from the group consisting of indium-doped tin oxide, phosphorus-doped tin oxide, and tungsten-doped tin oxide.

9. The carrier according to claim 1 ,
wherein the two or more kinds of inorganic particles include barium sulfate particles.

10. A developer, comprising:
a toner; and
the carrier for a developer of an electrostatic latent image according to claim 1 .

11. An image forming apparatus, comprising:
an electrostatic latent image-forming unit configured to form an electrostatic latent image on an electrostatic latent image-bearing member;
a developing unit configured to develop the electrostatic latent image formed on the electrostatic latent image-bearing member with a developer to form a toner image, where the developer includes the carrier for a developer of an electrostatic latent image according to claim 1 and a toner;
a transferring unit configured to transfer the toner image formed on the electrostatic latent image-bearing member to a recording medium; and
a fixing unit configured to fix the toner image transferred to the recording medium.

12. The carrier according to claim 1 ,
wherein the surface roughness of the carrier is from 1.42 m 2 /g through 1.90 m 2 /g.

13. The carrier according to claim 1 ,
wherein the surface roughness of the carrier is from 1.58 m 2 /g through 1.90 m 2 /g.

14. The carrier according to claim 1 ,
wherein the BET specific surface area of the carrier is from 1.76 m 2 /g through 2.50 m 2 /g.

15. The carrier according to claim 8 ,
wherein at least one kind of inorganic particles is tungsten-doped tin oxide.

Assignees

• Seki Masahiro
• Kishida Hiroyuki
• Murata Haruki
• Nakagawa Shinya
• Niwayama Kei
• Yamada Saori
• Miyazaki Kohsuke
• Ricoh Co Ltd

Inventors

• Seki Masahiro
• Kishida Hiroyuki
• Murata Haruki
• Nakagawa Shinya
• Niwayama Kei
• Yamada Saori
• Miyazaki Kohsuke

Classifications

• G03G9/1139

  Inorganic components of coatings · CPC title

• G03G9/1132

  Macromolecular components of coatings · CPC title

• G03G9/1131 Primary

  Coating methods; Structure of coatings · CPC title

• G03G15/0806

  on a donor element, e.g. belt, roller (complete developer unit G03G15/0896) · CPC title

• G03G9/1075

  Structural characteristics of the carrier particles, e.g. shape or crystallographic structure · CPC title