Electrophotographic image forming method and full color toner set for developing electrostatic image

Patent metadata

Field	Value
Publication number	US-9921506-B2
Application number	US-201615209866-A
Country	US
Kind code	B2
Filing date	Jul 14, 2016
Priority date	Aug 12, 2015
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

Provided is a method of forming an electrophotographic image using a plurality of color toners, the method containing: a charging step; an exposing step; a developing step; and a transferring step, wherein the plurality of color toners each respectively contain toner particles including a binder resin, a coloring agent, a releasing agent, and a crystalline resin; the binder resin contains an amorphous vinyl polymer formed with a vinyl monomer; the toner particles contain the amorphous vinyl polymer in the range of 10 to 90 mass %; and a maximum value of an acid value difference of the color toners is in the range of 1 to 10 mg KOH/g.

First claim

What is claimed is:

1. A method of forming an electrophotographic image using a plurality of color toners, the method comprising: a charging step; an exposing step; a developing step; and a transferring step,
wherein the plurality of color toners each respectively contain toner particles including a binder resin, a coloring agent, a releasing agent, and a crystalline resin;
the binder resin comprises an amorphous vinyl polymer formed with vinyl monomers, and the vinyl monomers comprise a vinyl monomer having a carboxy group in a range of 2 to 7 mass %;
the toner particles contain the amorphous vinyl polymer in the range of 10 to 90 mass %; and
a maximum value of an acid value difference of the color toners is in the range of 1 to 10 mg KOH/g.

2. The method of forming an electrophotographic image described in claim 1 ,
wherein the amorphous vinyl polymer is a styrene-acrylic resin; and
the styrene-acrylic resin contains a structural unit derived from an alkyl (meth)acrylate monomer represented by Formula (1),
H 2 C═CR 1 —COOR 2   Formula (1):

wherein R 1 represents a hydrogen atom or a methyl group; and R 2 represents an alkyl group of 6 to 22 carbon atoms.

3. The method of forming an electrophotographic image described in claim 2 ,
wherein R 2 in Formula (1) represents a branched alkyl group of 6 to 22 carbon atoms.

4. The method of forming an electrophotographic image described in claim 1 ,
wherein the toner particles in the plurality of color toners contain the amorphous vinyl polymer in the range of 50 to 80 mass %.

5. The method of forming an electrophotographic image described in claim 1 ,
wherein the crystalline resin is a crystalline polyester resin.

6. The method of forming an electrophotographic image described in claim 5 ,
wherein the crystalline polyester resin is a hybrid resin having an amorphous resin segment bonded with a chemical bond.

7. The method of forming an electrophotographic image described in claim 1 ,
wherein the plurality of color toners each are a yellow toner, a magenta toner, a cyan toner, and a black toner.

8. The method of forming an electrophotographic image described in claim 1 ,
wherein the maximum value of an acid value difference of the color toners is in the range of 2 to 6 mg KOH/g.

9. The method of forming an electrophotographic image described in claim 1 ,
wherein the crystalline resin contained in the toner particles is in the range of 1 to 30 mass %.

10. A full color toner set for developing an electrostatic image, the full color toner set comprising a plurality of color toners,
wherein the plurality of color toners each respectively contain toner particles including a binder resin, a coloring agent, a releasing agent, and a crystalline resin;
the binder resin comprises an amorphous vinyl polymer formed with vinyl monomers, and the vinyl monomers comprise a vinyl monomer having a carboxy group in a range of 2 to 7 mass %;
the toner particles contain the amorphous vinyl polymer in the range of 10 to 90 mass %; and
a maximum value of an acid value difference of the color toners is in the range of 1 to 10 mg KOH/g.

11. The full color toner set described in claim 10 , wherein the amorphous vinyl polymer is a styrene-acrylic resin; and
the styrene-acrylic resin contains a structural unit derived from an alkyl (meth)acrylate monomer represented by Formula (1),
H 2 C═CR 1 —COOR 2   Formula (1);

wherein R 1 represents a hydrogen atom or a methyl group; and R 2 represents an alkyl group of 6 to 22 carbon atoms.

12. The full color toner set described in claim 11 , wherein R 2 in Formula (1) represents a branched alkyl group of 6 to 22 carbon atoms.

13. The full color toner set described in claim 10 , wherein the toner particles in the plurality of color toners contain the amorphous vinyl polymer in the range of 50 to 80 mass %.

14. The full color toner set described in claim 10 , wherein the crystalline resin is a crystalline polyester resin.

15. The full color toner set described in claim 14 , wherein the crystalline polyester resin is a hybrid resin having an amorphous resin segment bonded with a chemical bond.

16. The full color toner set described in claim 10 , wherein the plurality of color toners each are a yellow toner, a magenta toner, a cyan toner, and a black toner.

17. The full color toner set described in claim 10 , wherein the maximum value of an acid value difference of the color toners is in the range of 2 to 6 mg KOH/g.

18. The full color toner set described in claim 10 , wherein the crystalline resin contained in the toner particles is in the range of 1 to 30 mass %.

19. The full color toner set described in claim 10 , wherein each of the color toners has an acid value in the range of 21 to 37 mg KOH/g.

20. The full color toner set described in claim 10 , wherein at least two toners of the toner set have different amounts of the vinyl monomer having the carboxy group.

Assignees

• Konica Minolta Inc

Inventors

• Hirano Shiro
• Tonegawa Naoya
• Matsubara Masaharu
• Sekiguchi Kouji
• Iioka Atsushi

Classifications

• G03G9/08755

  Polyesters · CPC title

• G03G9/0918

  Phthalocyanine dyes · CPC title

• G03G15/0121

  for developing · CPC title

• G03G9/08728 Primary

  Polymers of esters · CPC title

• G03G9/08711

  with esters of acrylic or methacrylic acid · CPC title