Magnetic toner

Patent metadata

Field	Value
Publication number	US-10877387-B2
Application number	US-201916583945-A
Country	US
Kind code	B2
Filing date	Sep 26, 2019
Priority date	Oct 2, 2018
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A magnetic toner comprising a magnetic toner particle including a binder resin, a magnetic body and a crystalline polyester, wherein a storage elastic modulus E′(40) [Pa] at 40° C. and a storage elastic modulus E′(85) [Pa] at 85° C., which are obtained in a powder dynamic viscoelasticity measurement of the magnetic toner, satisfy the following formulas (1) to (3).

E ′(40)≥6.0×10 9   (1)

E ′(85)≤5.5×10 9   (2)

[ E ′(40)− E ′(85)]×100/ E ′(40)≥40  (3)

First claim

What is claimed is:

1. A magnetic toner, comprising:
a magnetic toner particle including a binder resin, a magnetic body and a crystalline polyester, wherein
E′(40)≥6.0×10 9 ,
E′(85)≤5.5×10 9 , and
[E′(40)−E′(85)]×100/E′(40)≥40
where E′(40) [Pa] is a storage elastic modulus at 40° C. and E′(85) [Pa] is a storage elastic modulus at 85° C., which are obtained in a powder dynamic viscoelasticity measurement of the magnetic toner.

2. The magnetic toner according to claim 1 , wherein the binder resin comprises an amorphous polyester including a monomer unit derived from an aromatic diol and/or a monomer unit derived from an aromatic dicarboxylic acid.

3. The magnetic toner according to claim 2 , wherein a content ratio of the monomer unit derived from an aromatic diol and the monomer unit derived from an aromatic dicarboxylic acid is 85 mol % or more based on the total monomer units constituting the amorphous polyester.

4. The magnetic toner according to claim 1 , wherein a variation coefficient CV3 of an occupied area ratio of the magnetic bodies is 40.0 to 90.0% when a cross section of the magnetic toner particle is divided by a square grid having a side of 0.8 μm is observed using a transmission electron microscope.

5. The magnetic toner according to claim 1 , wherein domains of the crystalline polyester having a number average diameter of 50 to 500 nm are observed in a cross section of the magnetic toner particle using a transmission electron microscope.

6. The magnetic toner according to claim 1 , wherein a variation coefficient CV4 of an occupied area ratio of the crystalline polyester is 30.0 to 90.0% when a cross section of the magnetic toner particle is divided by a square grid having a side of 0.8 μm is observed using a transmission electron microscope.

7. The magnetic toner according to claim 1 , wherein the crystalline polyester comprises a monomer unit derived from an aliphatic diol having 2 to 12 carbon atoms, and/or a monomer unit derived from an aliphatic dicarboxylic acid having 2 to 12 carbon atoms.

8. The magnetic toner according to claim 1 , wherein E′(85)≤5.0×10 9 .

9. The magnetic toner according to claim 1 , wherein CV2/CV1≤1.00
when Dn (μm) is a number average particle diameter of the magnetic toner, CV1 (%) is a variation coefficient of a brightness dispersion value of the magnetic toner in a range from Dn−0.500 to Dn+0.500, and CV2 (%) is a variation coefficient of a brightness dispersion value of the magnetic toner in a range from Dn−1.500 to Dn−0.500, and 60.0.

Assignees

• Canon Kk

Inventors

• Fukudome Kosuke
• Kinumatsu Tetsuya
• Hasegawa Yusuke

Classifications

• G03G9/083 Primary

  Magnetic toner particles · CPC title

• G03G9/08755

  Polyesters · CPC title

• G03G9/08797

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

• G03G9/0821

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

• G03G9/0838

  Size of magnetic components · CPC title