Negatively-chargeable toner and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-9811018-B2
Application number	US-201415038212-A
Country	US
Kind code	B2
Filing date	Nov 28, 2014
Priority date	Nov 28, 2013
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Provided are a method for producing a negatively-chargeable toner that has a narrow particle diameter distribution even when produced by a polymerization method, and a negatively-chargeable toner that is excellent in balance between low-temperature fixability and heat-resistant shelf stability, has fine thin-line reproducibility, and generates little fog, even in high-speed printing. The negatively-chargeable toner includes colored resin particles which contain at least a binder resin, a colorant, a charge control agent and a softening agent, wherein the charge control agent is a copolymer which is obtained by copolymerizing a vinyl aromatic hydrocarbon, a (meth)acrylate and a sulfonic acid group-containing (meth)acrylamide and in which a copolymerization ratio of the sulfonic acid group-containing (meth)acrylamide is 0.8 to 4.0% by mass, and wherein the softening agent is at least one of a monoester compound and a polyglycerol ester compound.

First claim

The invention claimed is:

1. A negatively-chargeable toner comprising colored resin particles which contain at least a binder resin, a colorant, a charge control agent and a softening agent,
wherein the charge control agent is a copolymer which is obtained by copolymerizing a vinyl aromatic hydrocarbon, a (meth)acrylate and a sulfonic acid group-containing (meth)acrylamide and in which a copolymerization ratio of the sulfonic acid group-containing (meth)acrylamide in the copolymer is 0.8 to 4.0% by mass, and a weight average molecular weight of the charge control agent is 5,000 to 25,000, and
wherein the softening agent is at least one of a monoester compound and a polyglycerol ester compound.

2. The negatively-chargeable toner according to claim 1 , wherein the colorant is carbon black.

3. The negatively-chargeable toner according to claim 1 , wherein an amount of the softening agent is 1 to 25 parts by mass with respect to 100 parts by mass of the binder resin.

4. The negatively-chargeable toner according to claim 1 , wherein an amount of the charge control agent is 0.1 to 8 parts by mass with respect to 100 parts by mass of the binder resin.

5. The negatively-chargeable toner according to claim 1 , wherein the toner is obtained by a suspension polymerization method.

6. The negatively-chargeable toner according to claim 1 , wherein the negatively-chargeable toner has a core-shell structure.

7. A method for producing a negatively-chargeable toner, the method comprising:
a suspension step in which, by suspending a polymerizable monomer composition which contains at least a polymerizable monomer, a colorant, a charge control agent and a softening agent in an aqueous dispersion medium which contains a dispersion stabilizer, a suspension in which droplets of the polymerizable monomer composition are dispersed is obtained, and
a step of obtaining colored resin particles by carrying out suspension polymerization of the droplets of the polymerizable monomer composition in the suspension in the presence of a polymerization initiator,
wherein, in the suspension step, a copolymer which is obtained by copolymerizing a vinyl aromatic hydrocarbon, a (meth)acrylate and a sulfonic acid group-containing (meth)acrylamide and in which a copolymerization ratio of the sulfonic acid group-containing (meth)acrylamide in the copolymer is 0.8 to 4.0% by mass, is used as the charge control agent, and a weight average molecular weight of the charge control agent is 5,000 to 25,000, and
wherein, in the suspension step, at least one of a monoester compound and a polyglycerol ester compound is used as the softening agent.

8. The method for producing the negatively-chargeable toner according to claim 7 , wherein an amount of the softening agent is 1 to 25 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

9. The method for producing the negatively-chargeable toner according to of claim 7 , wherein an amount of the charge control agent is 0.1 to 8 parts by mass with respect to 100 parts by mass of the polymerizable monomer.

10. The method for producing the negatively-chargeable toner according to claim 7 , wherein the negatively-chargeable toner has a core-shell structure.

Assignees

• Zeon Corp

Inventors

• Taguchi Hiroyuki
• Kurokawa Hisashi

Classifications

• G03G9/09775 Primary

  containing atoms other than carbon, hydrogen or oxygen (G03G9/09741 - G03G9/09766 take precedence) · CPC title

• G03G9/0806

  whereby chemical synthesis of at least one of the toner components takes place · CPC title

• G03G9/0904

  Carbon black · CPC title

• G03G9/08755

  Polyesters · CPC title