Toner for electrostatic charge image development and image forming method
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)
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.