Toner for developing electrostatic image, image forming apparatus, image forming method, and process cartridge

Patent metadata

Field	Value
Publication number	US-9448501-B2
Application number	US-201314373396-A
Country	US
Kind code	B2
Filing date	Feb 7, 2013
Priority date	Feb 21, 2012
Publication date	Sep 20, 2016
Grant date	Sep 20, 2016

Abstract

A toner for developing an electrostatic image, which contains: resin particles (C), wherein the resin particles (C) each contain a resin particle (B) and resin particles (A) or a coating film (P) deposited on a surface of the resin particle (B), where the resin particle (B) contains a second resin (b) and a filler (f), wherein the resin particles (A) or the coating film (P) contains a first resin (a), wherein the second resin (b) contains a crystalline resin, and wherein the resin particle (B) contains the filler (f) in an amount of 15% by mass or greater.

First claim

The invention claimed is:

1. A toner for developing an electrostatic image, comprising:
resin particles (C), wherein the resin particles (C) each comprise
a resin particle (B) and resin particles (A), or
a coating film (P) deposited on a surface of the resin particle (B),

wherein the resin particle (B) comprises:
(b) a second resin comprising a crystalline polyester resin comprising a urethane bond and/or a urea bond; and
(f) 15% by mass or more of a filler comprising a carbonate, and

wherein the resin particles (A) or the coating film (P) comprise:
a first resin, which is a polyester resin.

2. The toner according to claim 1 , wherein the toner has a ratio (CC)/((CC)+(AA)) of 0.15 or greater, where (CC) is an integrated intensity of part of a spectrum derived from a crystal structure, and (AA) is an integrated intensity of a part of the spectrum derived from a non-crystal structure, where the spectrum is a diffraction spectrum of the toner obtained by an X-ray diffractometer.

3. The toner according to any of claim 1 , wherein the toner satisfies expressions (1) and (2):
( T 1− T 2)≦30° C.  (1),

T 2≧30° C.  (2)

wherein
T1 is a maximum endothermic peak obtained from a second heating from 0° C. to 150° C., and
T2 is a maximum exothermic peak obtained from cooling in differential scanning calorimetry (DSC) of the toner, in which the heating from 0° C. to 100° C. is performed at a heating rate of 10° C./min, and the cooling is performed from 100° C. to 0° C. at a cooling rate of 10° C./min.

4. The toner according to claim 1 , wherein a proportion of a tetrahydrofuran (THF) soluble component having a molecular weight of 100,000 or greater in the toner as measured by gel permeation chromatography (GPC) is 5% or greater, and the toner has a weight average molecular weight (Mw) of 15,000 to 70,000.

5. The toner according to claim 1 , wherein the toner has a ratio of ΔH(H)/ΔH(T) in the range of 0.2 to 1.25,
wherein
ΔH(T) is an endothermic value (J/g) of the toner as measured by DSC, and
ΔH(H) is an endothermic value (J/g) of a component of the toner as measured by DSC, the component of the toner being insoluble to a mixed solvent of THF and ethyl acetate mixed in a mass ratio (THF/ethyl acetate) of 50/50.

6. The toner according to claim 1 , wherein the second resin (b) comprises the crystalline polyester resin in an amount of 50% by mass or greater.

7. The toner according to claim 1 , wherein the resin particle (B) comprises from 15% by mass to 60% by mass of the filler (f).

8. The toner according to claim 1 , wherein the filler (f) comprises a stearic acid-treated carbonate.

9. The toner according to claim 1 , wherein the filler (f) has an average primary particle diameter of 5 nm to 1,000 nm.

10. The toner according to claim 1 , wherein the first resin (a) is a polyester resin comprising a polybasic acid and a polyhydric alcohol.

11. The toner according to claim 10 , wherein the polyester resin of the first resin (a) has an acid value of 10 mgKOH/g to 40 mgKOH/g.

12. The toner according to claim 1 , wherein the first resin (a) is a polyester resin, which comprises a basic compound.

13. An image forming apparatus, comprising:
a latent electrostatic image bearing member;
a charging unit configured to charge a surface of the latent electrostatic image bearing member;
an exposing unit configured to expose the charged surface of the latent electrostatic image bearing member to light to form a latent electrostatic image;
a developing unit, which houses a toner, and configured to develop the latent electrostatic image with the toner to form a visible image;
a transferring unit configured to transfer the visible image to a recording medium; and
a fixing unit configured to fix the transferred visible image to the recording medium,
wherein the toner is a toner for developing an electrostatic image,
wherein the toner for developing an electrostatic image comprises:
resin particles (C), wherein the resin particles (C) each comprise
a resin particle (B) and resin particles (A), or
a coating film (P) deposited on a surface of the resin particle (B), wherein the resin particle (B) comprises:

(b) a second resin comprising a crystalline polyester resin comprising a urethane bond and/or a urea bond; and
(f) 15% by mass or more of a filler comprising a carbonate, and

wherein the resin particles (A) or the coating film (P) comprise:
(a) a first resin, which is a polyester resin.

14. An image forming method, comprising:
charging a surface of a latent electrostatic image bearing member;
exposing the charged surface of the latent electrostatic image bearing member to light to form a latent electrostatic image;
developing the latent electrostatic image with a toner to form a visible image;
transferring the visible image to a recording medium; and
fixing the transferred visible image to the recording medium,
wherein the toner is a toner for developing an electrostatic image,
wherein the toner for developing an electrostatic image comprises:
resin particles (C), wherein the resin particles (C) each comprise
a resin particle (B) and resin particles (A), or
a coating film (P) deposited on a surface of the resin particle (B),

wherein the resin particle (B) comprises:
(b) a second resin comprising a crystalline polyester resin comprising a urethane bond and/or a urea bond; and
(f) 15% by mass or more of a filler comprising a carbonate, and

wherein the resin particles (A) or the coating film (P) comprise:
(a) a first resin which is a polyester resin.

15. The toner according to claim 9 , wherein the filler (f) has an average primary particle diameter of 700 nm to 1,000 nm.

Assignees

• Inoue Ryota
• Sekiguchi Yoshitaka
• Katoh Hiroaki
• Saito Shun
• Ricoh Co Ltd

Inventors

• Inoue Ryota
• Sekiguchi Yoshitaka
• Katoh Hiroaki
• Saito Shun

Classifications

• G03G9/08795

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

• G03G9/08755 Primary

  Polyesters · CPC title

• G03G9/0821

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

• G03G9/0806

  whereby chemical synthesis of at least one of the toner components takes place · CPC title

• G03G9/08797

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