Carrier, two-component developer, developer for replenishment, process cartridge, image forming apparatus, and image forming method

Patent metadata

Field	Value
Publication number	US-10054868-B2
Application number	US-201615331118-A
Country	US
Kind code	B2
Filing date	Oct 21, 2016
Priority date	Nov 27, 2015
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

A carrier includes a core and a covering layer covering the core and including at least carbon black and a filler. The maximum height Ry of the surface of the carrier is from 4.0 μm to 5.0 μm.

First claim

What is claimed is:

1. A carrier, comprising:
a magnetic core and
a covering layer, covering the core and including at least a covering resin, carbon black, and a filler,
wherein
the carrier has a surface with a maximum height Ry of from 4.0 μm to 5.0 μm, and
the filler has a particle diameter of from 400 nm to 800 nm.

2. The carrier of claim 1 , wherein the carbon black has a DBP oil absorption of not less than 400 ml/100 g.

3. The carrier of claim 1 , wherein the filler is at least one selected from the group consisting of barium sulfate, hydrotalcite and magnesium oxide.

4. A two-component developer, comprising:
the carrier according to claim 1 ; and
a toner.

5. The two-component developer of claim 4 , wherein the toner is a color toner.

6. A developer for replenishment, comprising:
the carrier according to claim 1 ; and
a toner in an amount of from 2 to 50 parts by mass relative to 1 part by mass of the carrier.

7. A process cartridge, comprising:
an electrostatic latent image bearer;
a charger to charge a surface of the electrostatic latent image bearer;
an image developer to develop an electrostatic latent image formed on the electrostatic latent image bearer with the two-component developer according to claim 4 ; and
a cleaning member to clean the electrostatic latent image bearer.

8. An image forming apparatus, comprising:
an electrostatic latent image bearer;
a charger to charge a surface of the electrostatic latent image bearer;
an irradiator to irradiate the surface of the electrostatic latent image bearer to form an electrostatic latent image on the surface of the electrostatic latent image bearer;
an image developer to develop the electrostatic latent image with the two-component developer according to claim 4 to foam a toner image;
a transferor to transfer the toner image onto a recording medium; and
a fixer to fix the toner image on the recording medium.

9. An image forming method, comprising:
forming an electrostatic latent image on an electrostatic latent image bearer;
developing the electrostatic latent image with the two-component developer according to claim 4 to form a toner image on a surface of the electrostatic latent image bearer;
transferring the toner image onto a recording medium; and
fixing the toner image on the recording medium.

10. The carrier of claim 1 , wherein the covering resin comprises a silicone resin, an acrylic resin, or a combination thereof.

11. The carrier of claim 1 , wherein the covering resin comprises an acrylic resin and the tiller is present in the acrylic resin.

12. The carrier of claim 1 , wherein the covering layer further comprises a crosslinked material of an acrylic resin and an amino resin.

13. The carrier of claim 1 , wherein the covering layer further comprises a silane coupling agent.

14. The carrier of claim 1 , wherein the filler is at least one selected from the group consisting of titanium oxide, tin oxide, zinc oxide, alumina, barium sulfide, magnesium oxide, magnesium hydroxide, and hydrotalcite.

Assignees

• Kishida Hiroyuki
• Mashiko Kenichi
• Takii Mariko
• Murasawa Yoshihiro
• Murata Haruki
• Ricoh Co Ltd

Inventors

• Kishida Hiroyuki
• Mashiko Kenichi
• Takii Mariko
• Murasawa Yoshihiro
• Murata Haruki

Classifications

• G03G15/08

  using a solid developer, e.g. powder developer · CPC title

• G03G9/10 Primary

  characterised by carrier particles · CPC title

• G03G9/1139 Primary

  Inorganic components of coatings · CPC title