IP Library › Granted Patent US 11,061,343
Granted Patent B2
US 11,061,343 · App. 16/793,039 · Granted Jul 13, 2021

Toner, toner stored unit, and image forming apparatus

Inventors: Yuka Mizoguchi (Shizuoka, JP); Ryota Inoue (Shizuoka, JP); Hiroshi Yamashita (Shizuoka, JP); Minoru Masuda (Shizuoka, JP); Daichi Hisakuni (Shizuoka, JP); Tomomi Harashima (Kanagawa, JP)
Assignee: Ricoh Company, Ltd.
G03G9/0902G03G9/0827G03G9/08755G03G9/08795G03G9/08797G03G9/0926G03G15/08
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Quick Facts
Patent No.
US 11,061,343
App. No.
16/793,039
Granted
Jul 13, 2021
Kind
B2
Abstract

A toner including: a plate-shaped pigment containing a metal as a main component; and a binder resin containing polyester resin (A) that is insoluble in THF, wherein: a weight average molecular weight (Mw) of a tetrahydrofuran (THF)-soluble component of the toner as determined by gel permeation chromatography (GPC) is 5,000 or higher but 14,000 or lower; and a glass transition temperature (Tg) of a THF-insoluble component of the toner as determined from a differential scanning colorimetry (DSC) curve at first heating in DSC is −60° C. or higher but 10° C. or lower.

Claims (18)

1. A toner comprising:

a plate-shaped pigment containing a metal as a main component; and

a binder resin containing polyester resin (A) that is insoluble in THF, wherein:

a weight average molecular weight (Mw) of a tetrahydrofuran (THF)-soluble component of the toner as determined by gel permeation chromatography (GPC) is 5,000 or higher but 14,000 or lower; and

a glass transition temperature (Tg) of a THE-insoluble component of the toner as determined from a differential scanning colorimetry (DSC) curve at first heating in DSC is −60° C. or higher but 10° C. or lower.

2. The toner according to claim 1 , wherein a proportion of the THF-insoluble component in the toner is 5% by mass or more but 15% by mass or less.

3. The toner according to claim 1 , wherein the polyester resin (A) contains at least one of a urethane bond and a urea bond.

4. The toner according to claim 1 , wherein the polyester resin (A) contains an alcohol component as a constituting component of the polyester resin (A), the alcohol component contains an aliphatic diol having from 3 through 10 carbon atoms in an amount of 50 mol % or more of the alcohol component, and a main chain of the aliphatic diol has a structure represented by General Formula (1) below:

where R 1 and R 2 are each independently a hydrogen atom or an alkyl group having from 1 through 3 carbon atoms, and n is an odd number of from 3 through 9, provided that R 1 and R 2 may be identical to or different from each other in units repeated in number of n.

5. The toner according to claim 1 , wherein the toner has a circularity of from 0.950 through 0.985.

6. A toner stored unit comprising

the toner according to claim 1 , which is stored in the toner stored unit.

7. An image forming apparatus comprising:

an electrostatic latent image bearer;

an electrostatic latent image forming unit configured to form an electrostatic latent image on the electrostatic latent image bearer;

a developing unit containing the toner according to claim 1 and configured to develop the electrostatic latent image formed on the electrostatic latent image bearer with the toner to form a toner image;

a transfer unit configured to transfer the toner image formed on the electrostatic latent image bearer onto a surface of a recording medium; and

a fixing unit configured to fix the toner image transferred onto the surface of the recording medium.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 18, 2020
From: MIZOGUCHI, YUKA; INOUE, RYOTA; YAMASHITA, HIROSHI; MASUDA, MINORU; HISAKUNI, DAICHI; HARASHIMA, TOMOMI
To: RICOH COMPANY, LTD.
Reel/Frame 051841/0502 →
Priority Claims (1)
JP JP2019-042630 · Mar 8, 2019 · national
Continuity (1)
Related Publication 20200285167A1 · Sep 10, 2020