IP Library › Granted Patent US 9,563,140
Granted Patent B2
US 9,563,140 · App. 14/060,800 · Granted Feb 7, 2017

Toner

Inventors: Tsuyoshi Nozaki (Osaka, JP); Takuya Kadota (Hyogo, JP); Yoshihiro Mikuriya (Hyogo, JP); Yoshimichi Ishikawa (Hyogo, JP); Kazuoki Fuwa (Hyogo, JP); Tomohiro Fukao (Osaka, JP); Tomoharu Miki (Osaka, JP)
Assignee: Ricoh Company, Ltd.
G03G9/0804G03G9/0825G03G9/08755G03G9/08782G03G9/08795G03G9/08797G03G9/09321G03G9/09371G03G9/09378G03G9/09392
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Quick Facts
Patent No.
US 9,563,140
App. No.
14/060,800
Granted
Feb 7, 2017
Kind
B2
Abstract

A toner is prepared by wet granulation methods, including a monoester wax having carbon atoms of from 36 to 46 on average as a release agent. The toner has a DSC endothermic energy amount (ΔH1) originating from the wax of from 10 to 12 mJ/mg and a DSC endothermic energy amount (ΔH2) originating from the wax of from 0.6 to 0.9 times as much as ΔH1 after a part of the wax is separated by hexane extraction from the toner. The hexane extraction includes mixing 1 g of the toner in 7 ml of n-hexane to prepare a mixture; stirring the mixture at 120 rpm for 1 min by a pot mill to prepare a dispersion; and subjecting the dispersion to suction filtration.

Claims (33)

1. A toner, comprising:

6 to 10% by weight of a monoester wax having carbon atoms of from 36 to 46 on average as a release agent,

a base, and

an inorganic particulate material,

wherein the toner has a DSC endothermic energy amount (ΔH1) originating from the wax of from 10 to 12 mJ/mg and a DSC endothermic energy amount (ΔH2) originating from the wax of from 0.6 to 0.9 times as much as ΔH1 when a part of the wax is separated by hexane extraction from the toner, and

wherein the hexane extraction comprises:

mixing 1 g of the toner in 7 ml of n-hexane to prepare a mixture;

stirring the mixture at 120 rpm for 1 min by a pot mill to prepare a dispersion; and

subjecting the dispersion to suction filtration,

wherein the base comprises:

a main part comprising a resin, the release agent and a colorant, and

a convex part formed of a particulate resin, overlying the main part,

wherein the toner has a sea-island structure where the main part is a sea and the convex part is an island, the resin comprises a first resin, and the particulate resin is different from the first resin, and

wherein the toner is prepared by a process comprising wet granulation.

2. The toner of claim 1 , wherein the first resin is a polyester resin and the particulate resin is a vinyl resin.

3. The toner of claim 1 , wherein the main part further comprises a modified polyester resin having a urethane and/or a urea group.

4. The toner of claim 1 , wherein the main part further comprises a crystalline polyester resin.

5. A process cartridge detachable from image forming apparatus, comprising:

a latent image bearer; and

an image developer containing a developer comprising the toner according to claim 1 .

6. A method of preparing the toner according to claim 1 , comprising:

dissolving or dispersing at least the resin, the colorant and the release agent in an organic solvent to prepare a solution or a dispersion comprising dissolved or dispersed materials;

placing the solution or the dispersion in an aqueous medium such that the dissolved or dispersed materials are suspended to prepare a core particle dispersion which is a main component;

adding a resin particle dispersion to the core particle dispersion to form a mixed dispersion in which the resin particles adhere to the surface of the core particles; and

removing the organic solvent from the mixed dispersion.

7. The method of claim 6 , wherein the aqueous medium comprises a surfactant.

8. The method of claim 6 , further comprising:

removing a part of the organic solvent from the mixed dispersion.

9. The method of claim 6 , wherein the core particle dispersion comprises an organic solvent in an amount of from 10 to 70% by weight based on total weight of the core particles.

10. The toner of claim 1 , which comprises 6 to 8% by weight of the monoester wax.

11. The toner of claim 1 , which comprises 6.5 to 7.5% by weight of the monoester wax.

12. The toner of claim 1 , wherein the monoester wax is behenyl behenate.

13. The toner of claim 1 , wherein the monoester wax is stearyl stearate.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Oct 23, 2013
From: NOZAKI, TSUYOSHI; KADOTA, TAKUYA; MIKURIYA, YOSHIHIRO; ISHIKAWA, YOSHIMICHI; FUWA, KAZUOKI; FUKAO, TOMOHIRO; MIKI, TOMOHARU
To: RICOH COMPANY, LTD.
Reel/Frame 031459/0792 →
Priority Claims (1)
JP 2012-260831 · Nov 29, 2012 · national
Continuity (1)
Related Publication 20140147780A1 · May 29, 2014