Toner, developing agent, toner stored unit, and image forming apparatus

Patent metadata

Field	Value
Publication number	US-12416872-B2
Application number	US-202117517359-A
Country	US
Kind code	B2
Filing date	Nov 2, 2021
Priority date	Nov 4, 2020
Publication date	Sep 16, 2025
Grant date	Sep 16, 2025

Abstract

The present disclosure provides a toner having excellent low-temperature fixing, heat-resistant-storage property, cleaning performance, and filming resistance. A toner containing toner base particles having a crystalline polyester resin and an amorphous polyester resin includes a plurality of organic particles disposed at least partially embedded in a surface of the toner base particles. A percentage of the crystalline polyester resin occupying the surface of the toner base particles is 4% to 20%, a volume average particle size of the organic particles is 10 nm to 40 nm, and a standard deviation of a distance between adjacent particles of the organic particles that are not in contact is 500 nm or less.

First claim

What is claimed is:

1. A toner, comprising toner base particles which comprise a crystalline polyester resin, an amorphous polyester resin and an amorphous hybrid resin, comprising:
a plurality of organic particles comprising resin particles comprising a styrene acrylic resin, disposed at least partially embedded in a surface of the toner base particles,
wherein a percentage of the crystalline polyester resin occupying the surface of the toner base particles is 4% to 20%,
a volume average particle size of the organic particles is 10 nm to 34.3 nm,

a standard deviation of a distance between adjacent particles of the organic particles that are not in contact is 500 nm or less,
said organic particles comprise:
organic particles (A) comprising styrene acrylic resin (a1) and styrene acrylic resin (a2); and

organic particles (B) comprising one type of styrene acrylic resin (a1), and
said amorphous hybrid resin comprises a polyester resin and a styrene resin which are partially chemically bonded.

2. The toner according claim 1 , wherein said styrene acrylic resin (a1) and (a2) each independently comprises a constitutional unit derived from a carboxylic acid.

3. The toner according to claim 1 , wherein a content of the organic particles with respect to a total mass of the toner base particles is 0.2% by mass to 5% by mass.

4. The toner according to claim 1 , wherein a percentage of the crystalline polyester resin occupying the surface of the toner base particles is 10% to 15%.

5. The toner according to claim 1 , wherein a glass transition temperature Tg 1st at the first temperature rise in a differential scanning calorimetry of the toner is 40° C. to 65° C.,
wherein a glass transition temperature Tg 1st of a tetrahydrofuran-insoluble content of the toner at the first temperature rise in DSC is −45° C. to 5° C., and
wherein a glass transition temperature Tg 2nd of a tetrahydrofuran-soluble content of the toner at the second temperature rise in DSC, is 20° C. to 65° C.

6. The toner according to claim 1 , wherein the amorphous polyester resin comprises a modified polyester.

7. The toner according to claim 6 , wherein the modified polyester contains a trivalent or tetravalent aliphatic polyhydric alcohol component with 3 to 10 carbon atoms.

8. The toner according to claim 6 , wherein the modified polyester contains a diol component, and the diol component has a carbon number of 3, 5, 7, or 9 in the main chain and an alkyl group in the side chain.

9. The toner according to claim 6 , wherein the modified polyester has a urethane bond, a urea bond, or both.

10. A developing agent comprising the toner of claim 1 , and a carrier.

11. A toner stored unit comprising the toner of claim 1 .

12. An image forming apparatus comprising:
an electrostatic latent image carrier;
an electrostatic latent image forming part that forms an electrostatic latent image on the electrostatic latent image carrier;
a developing part that develops the electrostatic latent image using a toner to form a visible image;
a transfer part that transfers the visible image to a recording medium; and
a fixing part that fixes the transferred image on the recording medium,
wherein the toner is the toner of claim 1 .

13. The toner according to claim 1 , wherein styrene acrylic resin (a1) comprises a styrene acrylic resin comprising a constitutional unit derived from a carboxylic acid.

Assignees

• Yoshida Ryuuta
• Takebayashi Toma
• Takei Akio
• Kamada Yasuo
• Ricoh Co Ltd

Inventors

• Yoshida Ryuuta
• Takebayashi Toma
• Takei Akio
• Kamada Yasuo

Classifications

• G03G9/0823

  Electric parameters · CPC title

• G03G9/108

  Ferrite carrier, e.g. magnetite · CPC title

• G03G9/1075

  Structural characteristics of the carrier particles, e.g. shape or crystallographic structure · CPC title

• B82Y40/00

  Manufacture or treatment of nanostructures · CPC title

• C08L33/06

  of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical · CPC title