Toner

Patent metadata

Field	Value
Publication number	US-9563140-B2
Application number	US-201314060800-A
Country	US
Kind code	B2
Filing date	Oct 23, 2013
Priority date	Nov 29, 2012
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

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.

First claim

What is claimed is:

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.

Assignees

• Nozaki Tsuyoshi
• Kadota Takuya
• Mikuriya Yoshihiro
• Ishikawa Yoshimichi
• Fuwa Kazuoki
• Fukao Tomohiro
• Miki Tomoharu
• Ricoh Co Ltd

Inventors

• Nozaki Tsuyoshi
• Kadota Takuya
• Mikuriya Yoshihiro
• Ishikawa Yoshimichi
• Fuwa Kazuoki
• Fukao Tomohiro
• Miki Tomoharu

Classifications

• G03G9/09378

  Non-macromolecular organic compounds · CPC title

• G03G9/0825

  characterised by their structure; characterised by non-homogenuous distribution of components (microcapsular toners G03G9/093) · CPC title

• G03G9/09371

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

• G03G9/0804 Primary

  whereby the components are brought together in a liquid dispersing medium · CPC title

• G03G9/08795

  characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants · CPC title