Carrier for developing electrostatic latent images, two-component developer, image forming apparatus, toner storing unit, and supplemental developer

Patent metadata

Field	Value
Publication number	US-9989874-B2
Application number	US-201715449572-A
Country	US
Kind code	B2
Filing date	Mar 3, 2017
Priority date	Mar 17, 2016
Publication date	Jun 5, 2018
Grant date	Jun 5, 2018

Abstract

A carrier for developing electrostatic latent images is provided. The carrier includes a magnetic core particle and a resin layer coating a surface of the magnetic core particle. The resin layer includes a particulate material A having a volume average particle diameter (a) and a particulate material B having a volume average particle diameter (b). The volume average particle diameter (a) of the particulate material A is the largest among volume average particle diameters of all particulate materials included in the resin layer, and an inequation 100≥(a)/(b)≥5 is satisfied. The particulate material A is barium sulfate.

First claim

The invention claimed is:

1. A carrier, comprising:
a magnetic core particle; and
a resin layer coating a surface of the magnetic core particle, the resin layer comprising a particulate material A having a volume average particle diameter (a) and a particulate material B having a volume average particle diameter (b),
wherein the volume average particle diameter (a) of the particulate material A is the largest among volume average particle diameters of all particulate materials included in the resin layer,
wherein an inequation 100≥(a)/(b)≥5 is satisfied, and
wherein the particulate material A is barium sulfate.

2. The carrier of claim 1 , wherein the volume average particle diameter (a) of the particulate material A is in the range of from 400 to 1,000 nm.

3. The carrier of claim 1 , wherein the particulate material B has conductivity.

4. The carrier of claim 1 , wherein the volume average particle diameter (b) of the particulate material B is in the range of from 4 to 100 nm.

5. The carrier of claim 1 , wherein the particulate material B is a tin oxide compound.

6. A two-component developer comprising:
the carrier of claim 1 ; and
a toner.

7. The two-component developer of claim 6 , wherein a concentration of the toner in the two-component developer ranges from 3% to 11% by mass.

8. The two-component developer of claim 6 , wherein the toner is at least one selected from the group consisting of a color toner, a white toner, and a transparent toner.

9. An image forming apparatus comprising:
an electrostatic latent image bearer;
a charger to charge the electrostatic latent image bearer;
an irradiator to form an electrostatic latent image on the electrostatic latent image bearer;
a developing device to develop the electrostatic latent image formed on the electrostatic latent image bearer into a toner image with the two-component developer of claim 6 ;
a transfer device to transfer the toner image formed on the electrostatic latent image bearer onto a recording medium; and
a fixing device to fix the toner image on the recording medium.

10. A toner storing unit comprising:
a storing unit; and
the two-component developer of claim 6 stored in the storing unit.

11. A supplemental developer comprising:
the carrier of claim 1 ; and
a toner.

12. The supplemental developer of claim 11 , wherein a content rate of the toner in the supplemental developer ranges from 2 to 50 parts by mass based on 1 part by mass of the carrier.

13. The carrier of claim 1 , wherein the particulate material B is selected from the group consisting of indium-doped tin oxide, phosphor-doped tin oxide, and tungsten-doped tin oxide.

14. The carrier of claim 1 , wherein the volume average particle diameter (b) of the particulate material B is in the range of from 25 to 50 nm.

Assignees

• Murasawa Yoshihiro
• Tano Toyoaki
• Kishida Hiroyuki
• Taikoji Masato
• Mashiko Kenichi
• Takii Mariko
• Murata Haruki
• Ricoh Co Ltd

Inventors

• Murasawa Yoshihiro
• Tano Toyoaki
• Kishida Hiroyuki
• Taikoji Masato
• Mashiko Kenichi
• Takii Mariko
• Murata Haruki

Classifications

• G03G9/0926

  characterised by physical or chemical properties · CPC title

• G03G9/1133

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• G03G2215/0607

  two-component · CPC title

• G03G9/1136

  containing silicon atoms · CPC title

• G03G9/1139

  Inorganic components of coatings · CPC title