Electrophotographic toner, two-component developer containing toner, and image forming apparatus

Patent metadata

Field	Value
Publication number	US-9354533-B2
Application number	US-201314029009-A
Country	US
Kind code	B2
Filing date	Sep 17, 2013
Priority date	Sep 18, 2012
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

To provide an electrophotographic toner, which contains a crystalline resin, a non-crystalline resin, a colorant, and a releasing agent, wherein the toner has a storage elastic modulus of 5.0×10 4 Pa to 5.0×10 6 Pa at 80° C., and a storage elastic modulus of 2.0×10 2 Pa to 2.0×10 3 Pa at 140° C., and wherein the toner has a ratio (C)/((C)+(A)) of 0.10 or greater, where (C) is an integrated intensity of a diffraction spectrum derived from a crystalline structure, (A) is an integrated intensity of a diffraction spectrum derived from a non-crystalline structure, and the diffraction spectrum is a diffraction spectrum of the toner as measured by an X-ray diffraction spectrometer.

First claim

What is claimed is:

1. An electrophotographic toner, comprising:
a crystalline resin;
a non-crystalline resin;
a colorant; and
a releasing agent,
wherein the toner has a storage elastic modulus of 5.0×10 4 Pa to 5.0×10 6 Pa at 80° C., and a storage elastic modulus of 2.0×10 2 Pa to 2.0×10 3 Pa at 140° C., and
wherein the toner has a ratio (C)/((C)+(A)) of 0.10 or greater, where (C) is an integrated intensity of a diffraction spectrum derived from a crystalline structure, (A) is an integrated intensity of a diffraction spectrum derived from a non-crystalline structure, and the diffraction spectrum is a diffraction spectrum of the toner as measured by an X-ray diffraction spectrometer,
wherein the non-crystalline resin has glass transition temperature of −60° C. or higher but lower than 0° C. as measured by a differential scanning calorimeter.

2. The electrophotographic toner according to claim 1 , wherein the ratio (C)/((C)+(A)) is 0.15 or greater.

3. The electrophotographic toner according to claim 1 , wherein the crystalline resin is a resin containing a crystalline polyester unit.

4. The electrophotographic toner according to claim 1 , wherein the crystalline resin is a crystalline polyester resin, and the non-crystalline resin is a non-crystalline polyester resin.

5. The electrophotographic toner according to claim 1 , wherein the crystalline resin, or the non-crystalline resin, or both thereof are a resin containing a urethane bond, or a urea bond, or both thereof.

6. The electrophotographic toner according to claim 1 , wherein the crystalline resin is a copolymer containing a crystalline polyester unit and a polyurethane unit.

7. The electrophotographic toner according to claim 1 , wherein the toner contains toner particles, which are produced by a method containing:
dispersing or emulsifying a toner composition in an aqueous medium to granulate toner particles, where the toner composition contains a binder resin containing the crystalline resin and the non-crystalline resin, the colorant, and the releasing agent.

8. The electrophotographic toner according to claim 1 , wherein the non-crystalline resin is formed by elongating or crosslinking a modified resin containing an isocyanate group at a terminal thereof.

9. A developer comprising:
a carrier; and
a toner,
wherein the toner contains:
a crystalline resin;
a non-crystalline resin;
a colorant; and
a releasing agent,
wherein the toner has a storage elastic modulus of 5.0×10 4 Pa to 5.0×10 6 Pa at 80° C., and a storage elastic modulus of 2.0×10 2 Pa to 2.0×10 3 Pa at 140° C., and
wherein the toner has a ratio (C)/((C)+(A)) of 0.10 or greater, where (C) is an integrated intensity of a diffraction spectrum derived from a crystalline structure, (A) is an integrated intensity of a diffraction spectrum derived from a non-crystalline structure, and the diffraction spectrum is a diffraction spectrum of the toner as measured by an X-ray diffraction spectrometer,
wherein the non-crystalline resin has glass transition temperature of −60° C. or higher but lower than 0° C. as measured by a differential scanning calorimeter.

10. The developer according to claim 9 , wherein the ratio (C)/((C)+(A)) is 0.15 or greater.

11. The developer according to claim 9 , wherein the crystalline resin is a resin containing a crystalline polyester unit.

12. The developer according to claim 9 , wherein the crystalline resin is a crystalline polyester resin, and the non-crystalline resin is a non-crystalline polyester resin.

13. The developer according to claim 9 , wherein the crystalline resin, or the non-crystalline resin, or both thereof are a resin containing a urethane bond, or a urea bond, or both thereof.

14. An image forming apparatus, comprising:
a latent electrostatic image bearing member;
a charging unit configured to charge a surface of the latent electrostatic image bearing member;
an exposing unit configured to expose the charged surface of the latent electrostatic image bearing member to light to form a latent electrostatic image;
a developing unit configured to develop the latent electrostatic image with a toner to form a visible image;
a transferring unit configured to transfer the visible image to a recording medium; and
a fixing unit configured to fix the transferred image, which has been transferred on the recording medium,
wherein the toner contains:
a crystalline resin;
a non-crystalline resin;
a colorant; and
a releasing agent,

wherein the toner has a storage elastic modulus of 5.0×104 Pa to 5.0×106 Pa at 80° C., and a storage elastic modulus of 2.0×102 Pa to 2.0×103 Pa at 140° C., and
wherein the toner has a ratio (C)/((C)+(A)) of 0.10 or greater, where (C) is an integrated intensity of a diffraction spectrum derived from a crystalline structure, (A) is an integrated intensity of a diffraction spectrum derived from a non-crystalline structure, and the diffraction spectrum is a diffraction spectrum of the toner as measured by an X-ray diffraction spectrometer,
wherein the non-crystalline resin has glass transition temperature of −60° C. or higher but lower than 0° C. as measured by a differential scanning calorimeter.

15. The image forming apparatus according to claim 14 , wherein the ratio (C)/((C)+(A)) is 0.15 or greater.

16. The image forming apparatus according to claim 14 , wherein the crystalline resin is a resin containing a crystalline polyester unit.

17. The image forming apparatus according to claim 14 , wherein the crystalline resin, or the non-crystalline resin, or both thereof are a resin containing a urethane bond, or a urea bond, or both thereof.

Assignees

• Ricoh Co Ltd

Inventors

• Takahashi Rintaro
• Suzuki Kazumi
• Shiba Masana
• Morita Tatsuya
• Yamauchi Yoshitaka
• Miyaake Azumi

Classifications

• G03G9/08797

  characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature · CPC title

• G03G9/0821 Primary

  characterised by physical parameters (magnetic parameters G03G9/083) · CPC title

• G03G9/08764

  Polyureas; Polyurethanes · CPC title

• G03G9/0804

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

• G03G9/08755

  Polyesters · CPC title