IP Library Granted Patent US 9,448,501
Granted Patent B2
US 9,448,501 · App. 14/373,396 · Granted Sep 20, 2016

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

Inventors: Ryota Inoue (Shizuoka, JP); Yoshitaka Sekiguchi (Shizuoka, JP); Hiroaki Katoh (Kyoto, JP); Shun Saito (Shizuoka, JP)
Assignee: Ricoh Company, Ltd.
G03G9/08755G03G9/0821G03G9/08795G03G9/08797G03G2215/0629
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Quick Facts
Patent No.
US 9,448,501
App. No.
14/373,396
Granted
Sep 20, 2016
Kind
B2
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.

Claims (61)

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.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 21, 2014
From: INOUE, RYOTA; SEKIGUCHI, YOSHITAKA; KATOH, HIROAKI; SAITO, SHUN
To: RICOH COMPANY, LTD.
Reel/Frame 033349/0718 →
Priority Claims (2)
JP 2012-035251 · Feb 21, 2012 · national
JP 2012-286922 · Dec 28, 2012 · national
Continuity (1)
Related Publication 20140363209A1 · Dec 11, 2014