IP Library Granted Patent US 10,234,783
Granted Patent B2
US 10,234,783 · App. 15/568,947 · Granted Mar 19, 2019

Carrier, developer, image forming apparatus, developer stored unit, and image forming method

Inventors: Koichi Sakata (Shizuoka, JP); Tohru Suganuma (Shizuoka, JP); Shohichi Sugimoto (Shizuoka, JP); Hiroshi Tohmatsu (Shizuoka, JP); Hiroyuki Kishida (Shizuoka, JP); Kenichi Mashiko (Shizuoka, JP); Toyoaki Tano (Shizuoka, JP)
Assignee: Ricoh Company, Ltd.
G03G9/1139G03G9/1136G03G9/1137
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Quick Facts
Patent No.
US 10,234,783
App. No.
15/568,947
Granted
Mar 19, 2019
Kind
B2
Abstract

A carrier including a resin layer including at least one kind of particles, wherein the at least one kind of the particles are particles of barium sulfate, wherein an amount of Ba detected is 0.3 atomic % or greater in a Ba analysis through X-ray photoelectron spectroscopy (XPS) of the carrier, and wherein circle-equivalent diameters of the particles of the barium sulfate are 400 nm or greater but 900 nm or smaller.

Claims (27)

1. A carrier, comprising

a resin layer including at least one kind of particles,

wherein

the at least one kind of particles are particles of barium sulfate,

an amount of Ba detected is 0.3 atomic % or greater in a Ba analysis through X-ray photoelectron spectroscopy of the carrier, and

circle-equivalent diameters of the particles of barium sulfate range greater than 400 nm to 900 nm.

2. The carrier according to claim 1 , wherein Ba is present at surfaces of the particles of barium sulfate.

3. The carrier according to claim 1 , wherein an amount of the particles of barium sulfate in the resin layer is from 50% by mass to 100% by mass, relative to a resin contained in the resin layer.

4. The carrier according to claim 1 , wherein a height d is 200 nm or greater, where the height d is a height of a projected part of barium sulfate exposed from a surface of the resin layer of the carrier.

5. The carrier according to claim 1 , wherein a major axis of a maximum exposed area is 300 nm or greater, where the maximum exposed area is a maximum exposed area among exposed areas of barium sulfate exposed from a surface of the resin layer of the carrier.

6. The carrier according to claim 1 , wherein a resin component of the resin layer contains a resin obtained by performing a heating process on a copolymer containing at least monomer component A, and monomer component B which is a cross-linking component, as shown below:

where R 1 is a hydrogen atom or a methyl group; in is an integer of from 1 through 8; R 2 is an alkyl group having from 1 through 4 carbon atoms; R 3 is an alkyl group having from 1 through 8 carbon atoms or an alkoxy group having from 1 through 4 carbon atoms; X is from 10 mol % through 90 mol %; and Y is from 10 mol % through 90 mol %.

7. A developer, comprising:

the carrier according to claim 1 ; and

a toner.

8. The developer according to claim 7 , wherein the toner is a color toner.

9. The developer according to claim 7 , wherein the developer contains the toner in an amount of from 2 parts by mass to 50 parts by mass relative to 1 part by mass of the carrier, and the developer is used as a supply developer.

10. 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 containing the developer according to claim 7 and configured to develop the electrostatic latent image formed on the electrostatic latent image bearer with the developer to form a toner image.

11. A developer stored unit, comprising

the developer according to claim 7 ,

wherein the developer is stored in the developer stored unit.

12. An image forming method, comprising:

forming an electrostatic latent image on an electrostatic latent image bearer; and

developing the electrostatic latent image formed on the electrostatic latent image bearer with the developer according to claim 7 to form a toner image.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 24, 2017
From: SAKATA, KOICHI; SUGANUMA, TOHRU; SUGIMOTO, SHOHICHI; TOHMATSU, HIROSHI; KISHIDA, HIROYUKI; MASHIKO, KENICHI; TANO, TOYOAKI
To: RICOH COMPANY, LTD.
Reel/Frame 043936/0915 →
Priority Claims (1)
JP 2015-095765 · May 8, 2015 · national
Continuity (1)
Related Publication 20180120724A1 · May 3, 2018