TONER FOR ELECTROSTATIC CHARGE IMAGE DEVELOPMENT

• US 20190310565A1
• Filed: 02/26/2019
• Published: 10/10/2019
• Est. Priority Date: 04/09/2018
• Status: Abandoned Application

• Current Assignee: Konica Minolta Inc.
• Original Assignee: Konica Minolta Inc.
• Inventors: TAKIGAURA, Yusuke, Kayamori, Takanari, Fujino, Kaori, Sakurada, Ikuko
• Application Number:
  US16/286,202
• Publication Number:
  US 20190310565A1
• Time in Patent Office: Days
• CPC Class Codes: G03G 9/0819 characterised by the dimensions of the particles
• CPC Class Codes: G03G 9/0827 characterised by their shape, e.g. degree of sphericity
• CPC Class Codes: G03G 9/08755 Polyesters
• CPC Class Codes: G03G 9/08795 characterised by their chemical properties, e.g. acidity, molecular weight, sensitivity to reactants
• CPC Class Codes: G03G 9/08797 characterised by their physical properties, e.g. viscosity, solubility, melting temperature, softening temperature, glass transition temperature
• CPC Class Codes: G03G 9/09708 Inorganic compounds
• CPC Class Codes: G03G 9/09716 treated with organic compounds
• CPC Class Codes: G03G 9/09725 Silicon-oxides; Silicates

Abstract

A toner for electrostatic charge image development includes: a toner base particle containing a binder resin; and an external additive containing a strontium titanate fine particle, wherein the binder resin contains an amorphous resin and a crystalline polyester resin, in which the crystalline polyester resin is a polycondensate of an aliphatic dicarboxylic acid having from 6 to 14 carbon atoms and an aliphatic diol having from 6 to 14 carbon atoms, and the strontium titanate fine particle contains a strontium titanate fine particle (A) and a strontium titanate fine particle (B), in which a particle diameter R_A of a peak top in number particle size distribution of the strontium titanate fine particle (A) is smaller than a particle diameter R_B of a peak top in number particle size distribution of the strontium titanate fine particle (B).

Claims

1. A toner for electrostatic charge image development comprising:

a toner base particle containing a binder resin; and

an external additive containing a strontium titanate fine particle, wherein

the binder resin contains an amorphous resin and a crystalline polyester resin, in which the crystalline polyester resin is a polycondensate of an aliphatic dicarboxylic acid having from 6 to 14 carbon atoms and an aliphatic diol having from 6 to 14 carbon atoms, and

the strontium titanate fine particle contains a strontium titanate fine particle (A) and a strontium titanate fine particle (B), in which a particle diameter R_A of a peak top in number particle size distribution of the strontium titanate fine particle (A) is smaller than a particle diameter R_B of a peak top in number particle size distribution of the strontium titanate fine particle (B).

2. The toner for electrostatic charge image development according to claim 1, wherein the particle diameter R_A of the strontium titanate fine particle (A) and the particle diameter R_B of the strontium titanate fine particle (B) satisfy relation of the following Formula (1):

200 nm≤

(R_B−

R_A)≤

3000 nm. 

 

Formula (1);

3. The toner for electrostatic charge image development according to claim 1, wherein the particle diameter R_A of the strontium titanate fine particle (A) is 10 nm or more and 100 nm or less.

4. The toner for electrostatic charge image development according to claim 3, wherein the particle diameter R_A of the strontium titanate fine particle (A) is 20 nm or more and 60 nm or less.

5. The toner for electrostatic charge image development according to claim 1, wherein the particle diameter R_B of the strontium titanate fine particle (B) is more than 300 nm and 2000 nm or less.

6. The toner for electrostatic charge image development according to claim 5, wherein the particle diameter R_B of the strontium titanate fine particle (B) is 310 nm or more and 1500 nm or less.

7. The toner for electrostatic charge image development according to claim 1, wherein contents of the strontium titanate fine particle (A) and the strontium titanate fine particle (B) are such that a contained mass ratio (A)/(B) satisfies relation of the following Formula (2):

0.5≤

(A)/(B)≤

2.5. 

 

Formula (2);

8. The toner for electrostatic charge image development according to claim 1, wherein either of the strontium titanate fine particle (A) or the strontium titanate fine particle (B) contains a fine particle having a cubic shape and/or a rectangular parallelepiped shape.

9. The toner for electrostatic charge image development according to claim 1, wherein at least either of the strontium titanate fine particle (A) or the strontium titanate fine particle (B) is a lanthanum-containing strontium titanate fine particle.