Electrostatic image developing toner, method for producing electrostatic image developing toner, electrostatic image developer, toner cartridge, process cartridge, and image forming apparatus

Patent metadata

Field	Value
Publication number	US-2022373909-A1
Application number	US-202117408058-A
Country	US
Kind code	A1
Filing date	Aug 20, 2021
Priority date	May 21, 2021
Publication date	Nov 24, 2022
Grant date	—

Abstract

An electrostatic image developing toner includes toner particles containing a binder resin. In a differential scanning calorimetry curve of the toner particles, Tg1 is 58° C. or more and 68° C. or less, and Tg1−Tg2 is 20° C. or more and 40° C. or less, where Tg1 is a lowest onset temperature in an endothermic change during a first temperature increase, and Tg2 is a lowest onset temperature in an endothermic change during a second temperature increase.

First claim

What is claimed is:

1 . An electrostatic image developing toner comprising toner particles containing a binder resin,
wherein in a differential scanning calorimetry curve of the toner particles, Tg1 is 58° C. or more and 68° C. or less, and Tg1−Tg2 is 20° C. or more and 40° C. or less, where Tg1 is a lowest onset temperature in an endothermic change during a first temperature increase, and Tg2 is a lowest onset temperature in an endothermic change during a second temperature increase.

2 . The electrostatic image developing toner according to claim 1 , wherein the toner particles have a BET specific surface area of 1.0 m 2 /g or more and 2.0 m 2 /g or less.

3 . The electrostatic image developing toner according to claim 1 , wherein the binder resin includes a polyester resin.

4 . The electrostatic image developing toner according to claim 3 , wherein the polyester resin includes a crystalline polyester resin.

5 . The electrostatic image developing toner according to claim 4 , wherein a content of the crystalline polyester resin is 5 mass % or more and 25 mass % or less relative to a total content of the binder resin.

6 . The electrostatic image developing toner according to claim 3 , wherein the binder resin further includes a vinyl resin.

7 . The electrostatic image developing toner according to claim 6 , wherein a content of the vinyl resin is 1 mass % or more and 30 mass % or less relative to a total content of the toner particles.

8 . A method for producing an electrostatic image developing toner, comprising:
cooling a toner particle dispersion in which toner particles containing a binder resin are dispersed in a dispersion medium from a fusion temperature of T1° C. or more to a first cooling temperature of less than T2° C.; holding the toner particle dispersion that has been cooled to the first cooling temperature at a holding temperature of T3° C. or more and T4° C. or less for 0.5 hours or more and 3 hours or less with a pH of the toner particle dispersion being lowered; and cooling the toner particle dispersion that has been held to a second cooling temperature less than 15° C. and lower than the holding temperature, wherein 11° C. is Tg0° C.+29° C., where Tg0° C. is a glass transition temperature of the toner particles before being cooled to the first cooling temperature, T2° C. is Tg0° C.+9° C., T3° C. is Tg0° C.+4° C., T4° C. is Tg0° C.+14° C., and T5° C. is Tg0° C.+9° C.

9 . The method for producing an electrostatic image developing toner according to claim 8 , wherein in the holding, the pH of the toner particle dispersion that has been cooled to the first cooling temperature is adjusted to 7.0 or more and 9.0 or less.

10 . The method for producing an electrostatic image developing toner according to claim 8 , wherein a cooling rate A1 in the cooling to the first cooling temperature is 30° C./min or more and 130° C./min or less.

11 . The method for producing an electrostatic image developing toner according to claim 8 , wherein the binder resin includes a polyester resin.

12 . The method for producing an electrostatic image developing toner according to claim 11 , wherein the polyester resin includes a crystalline polyester resin.

13 . The method for producing an electrostatic image developing toner according to claim 12 , wherein a content of the crystalline polyester resin is 5 mass % or more and 25 mass % or less relative to a total content of the binder resin.

14 . The method for producing an electrostatic image developing toner according to claim 11 , wherein the binder resin further includes a vinyl resin.

15 . The method for producing an electrostatic image developing toner according to claim 14 , wherein a content of the vinyl resin is 1 mass % or more and 30 mass % or less relative to a total content of the toner particles.

16 . An electrostatic image developing toner obtained by the method for producing an electrostatic image developing toner according to claim 8 .

17 . An electrostatic image developer comprising the electrostatic image developing toner according to claim 1 .

18 . A toner cartridge attachable to and detachable from an image forming apparatus, the toner cartridge comprising the electrostatic image developing toner according to claim 1 .

19 . A process cartridge attachable to and detachable from an image forming apparatus, the process cartridge comprising a developing unit that contains the electrostatic image developer according to claim 17 and develops, with the electrostatic image developer, an electrostatic image formed on a surface of an image carrier to form a toner image.

20 . An image forming apparatus comprising:
an image carrier; a charging unit that charges a surface of the image carrier; an electrostatic image forming unit that forms an electrostatic image on the charged surface of the image carrier; a developing unit that contains the electrostatic image developer according to claim 17 and develops, with the electrostatic image developer, the electrostatic image formed on the surface of the image carrier to form a toner image; a transfer unit that transfers the toner image formed on the surface of the image carrier onto a surface of a recording medium; and a fixing unit that fixes the toner image transferred onto the surface of the recording medium.

Assignees

• Fujifilm Business Innovation Corp

Inventors

• Tomita Daisuke
• Yamamoto Keita
• Noguchi Daisuke
• Nakamura Kazuhiko
• Nakazawa Hiroshi

Classifications

• G03G9/08702

  comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• G03G9/08797

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

• G03G9/08755 Primary

  Polyesters · CPC title

• G03G9/0821

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

• G03G9/08795 Primary

  characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants · CPC title