Toner for electrostatic charge image development and image forming method

Patent metadata

Field	Value
Publication number	US-9933717-B2
Application number	US-201715444465-A
Country	US
Kind code	B2
Filing date	Feb 28, 2017
Priority date	Mar 30, 2016
Publication date	Apr 3, 2018
Grant date	Apr 3, 2018

Abstract

The present invention relates to a toner for electrostatic charge image development, including: a toner base particle having at least a binder resin, a releasing agent, and a colorant, wherein the following formula (1) is satisfied wherein a maximum value and a minimum value of a dielectric loss tangent tan δ, which are obtained by measuring at a frequency in the range of 1 kHz to 100 kHz under the condition at a temperature of 20° C. and a relative humidity of 50% RH, are defined as tan δ max and tan δ min , respectively. According to the present invention, a toner for electrostatic charge image development, with which the rising of the toner charge amount is improved while ensuring the low temperature fixability, and a high quality image having less density unevenness can be obtained even during the image forming at a high speed and a high printing rate, is provided.

Frequency showing tan δ max <Frequency showing tan δ min   (1)

First claim

What is claimed is:

1. A toner for electrostatic charge image development, comprising:
a toner base particle comprising at least a binder resin, a releasing agent, and a colorant, wherein
the toner satisfies the following formula (1), wherein a maximum value and a minimum value of a dielectric loss tangent tan δ of the toner, which are obtained by measuring at a frequency in the range of 1 kHz to 100 kHz under the condition at a temperature of 20° C. and a relative humidity of 50% RH, are defined as tan δ max and tan δ min , respectively,
Frequency of tan δ max <Frequency of tan δ min   (1),

the binder resin comprises a crystalline polyester resin,
the toner base particle has a content of the crystalline polyester resin of 1 to 15% by mass, and
the colorant is a chromatic colorant.

2. The toner for electrostatic charge image development according to claim 1 ,
wherein the toner has a dielectric loss tangent tan δ 100 kHz measured at a frequency of 100 kHz satisfies the following formula (2)
tan δ 100 kHz ≤0.035  (2).

3. The toner for electrostatic charge image development according to claim 1 ,
wherein the toner has a relative dielectric constant ε′ at a frequency of 100 kHz is 2.0 or more.

4. The toner for electrostatic charge image development according to claim 1 ,
wherein Net intensity of a group 1 element measured by fluorescent X-ray analysis is 0.70 or more.

5. The toner for electrostatic charge image development according to claim 1 ,
wherein the binder resin comprises a vinyl resin.

6. An image forming method, comprising:
forming an electrostatic charge image on an image carrier by electrifying and exposing a surface of the image carrier;
forming a toner image by developing the electrostatic charge image formed on the image carrier with a developer comprising a toner;
transferring e toner image formed on the image carrier onto a recording medium; and
fixing the toner image transferred on the recording medium with a heat roller system,
wherein the toner is the toner for electrostatic charge image development set forth in claim 1 .

7. The toner for electrostatic charge image development according to claim 1 , wherein
the Net intensity of a group 1 element measured by fluorescent X-ray analysis is 0.70 or more to 3.0 or less.

8. The toner for electrostatic charge image development according to claim 1 , wherein
the content of the crystalline polyester resin in the toner base particle is 7 to 12% by mass.

Assignees

• Konica Minolta Inc

Inventors

• Fujisaki Tatsuya
• Ueda Noboru

Classifications

• G03G9/0821

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

• G03G9/0904

  Carbon black · CPC title

• G03G9/091

  Azo dyes · CPC title

• G03G9/08797

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

• G03G9/08711 Primary

  with esters of acrylic or methacrylic acid · CPC title