Toner

Patent metadata

Field	Value
Publication number	US-12529972-B2
Application number	US-202217808835-A
Country	US
Kind code	B2
Filing date	Jun 24, 2022
Priority date	Jul 2, 2021
Publication date	Jan 20, 2026
Grant date	Jan 20, 2026

Abstract

A toner comprising a toner particle comprising a binder resin, a nonmagnetic inorganic oxide particle A, and a magnetic iron oxide particle B, wherein a softening point of a chloroform-soluble component of the toner particle is not greater than 90° C.; the nonmagnetic inorganic oxide particle A and the magnetic iron oxide particle B are internally added to the toner particle; the nonmagnetic inorganic oxide particle A comprises as its main component at least one element selected from the group consisting of Si, Mg, Al, Ti, and Sr; a proportion of the inorganic oxide particles having a long diameter of specific length is in specific range; and a value of a ratio of a number-average particle diameter of the long diameter for the nonmagnetic inorganic oxide particle A, to a number-average particle diameter of the long diameter for the magnetic iron oxide particle B, is 5 to 30.

First claim

What is claimed is:

1 . A toner, comprising:
a toner particle comprising a binder resin, a nonmagnetic inorganic oxide particle A, and a magnetic iron oxide particle B; a softening point of a chloroform-soluble component of the toner particle being not greater than 90° C.; the nonmagnetic inorganic oxide particle A and the magnetic iron oxide particle B being internally added to the toner particle; and the nonmagnetic inorganic oxide particle A being a silica particle, wherein when a cross section of the toner particle provided by sectioning with a microtome is observed with transmission electron microscopy (i) a particle number of the nonmagnetic inorganic oxide particle A that is present per 1 toner particle cross section is 0.7 to 5.0, and (ii) a shape factor SF1 of the nonmagnetic inorganic oxide particle A is at least 143, where SF1 of the nonmagnetic inorganic oxide particle A=((LA) 2 /(AA))×(π/4)×100 when LA represents the absolute maximum length of the nonmagnetic inorganic oxide particle A (length of circumscribing circle) and AA represents the projected area of the nonmagnetic inorganic oxide particle A, and (iii) a shape factor SF1 of the magnetic iron oxide particle B is not more than 110, where SF1 of the magnetic iron oxide particle B=(LB) 2 /(AB)×(π/4)×100 when LB represents the absolute maximum length of the magnetic iron oxide particle B (length of circumscribing circle) and AB represents the projected area of the magnetic iron oxide particle B, at least 70 number % of the nonmagnetic inorganic oxide particles A having a long diameter of at least 100 nm have a long diameter of 400 to 3,000 nm, at least 70 number % of the magnetic iron oxide particles B have a long diameter of 50 to 350 nm, and a value of a ratio of a number-average particle diameter of the long diameter for the nonmagnetic inorganic oxide particle A to a number-average particle diameter of the long diameter for the magnetic iron oxide particle B is 5 to 30.

2 . The toner according to claim 1 , wherein a value of a ratio of a number of magnetic iron oxide particles B to a number of nonmagnetic inorganic oxide particles A present in a cross section of the toner particle provided by sectioning with a microtome is 50 to 500 when observed with transmission electron microscopy.

3 . The toner according to claim 1 , wherein at least 70 number % of nonmagnetic inorganic oxide particles A having a long diameter of at least 100 nm have a long diameter of 800 to 3,000 nm.

4 . The toner according to claim 1 , wherein a value of a ratio of a weight-average particle diameter of the toner to the number-average particle diameter of the long diameter for the nonmagnetic inorganic oxide particle A is 2 to 15.

5 . The toner according to claim 1 , wherein the binder resin comprises an amorphous polyester resin.

6 . The toner according to claim 5 , wherein a content of the amorphous polyester resin in the binder resin is at least 50 mass %.

7 . The toner according to claim 1 , wherein the binder resin has a number-average molecular weight (Mn) of 1,000 to 5,000.

8 . The toner according to claim 1 , wherein magnetic iron oxide particle B has a residual magnetization (or) of 4 to 18 Am 2 /kg.

Assignees

• Canon Kk

Inventors

• Nozaki Dai
• Suzumura Yoshitaka
• Unno Tomohiro

Classifications

• G03G9/0819

  characterised by the dimensions of the particles · CPC title

• G03G9/09725

  Silicon-oxides; Silicates · CPC title

• G03G9/0833

  Oxides · CPC title

• G03G9/08795

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

• G03G9/081 Primary

  by mixing the toner components in a liquefied state; melt kneading; reactive mixing · CPC title