Toner, developer, toner storage unit, image forming apparatus, image forming method, and method for producing printed matter

Patent metadata

Field	Value
Publication number	US-10627732-B2
Application number	US-201815911285-A
Country	US
Kind code	B2
Filing date	Mar 5, 2018
Priority date	Mar 14, 2017
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

A toner is provided. The toner includes at least two types of polyester resins and a release agent. When the toner is subjected to a dynamic viscoelasticity measurement at a frequency of 6.28 rad/sec to obtain a temperature-dependent curve of loss tangent (tan δ), and the temperature-dependent curve is differentiated one time with temperature, a resulting curve has a maximum value of 0.07 or more and a minimum value of 0.025 or less within a temperature range of from 85° C. to 110° C. When the toner is subjected to a differential scanning calorimetry (DSC), an endothermic amount measured in a first temperature rising in the DSC is 3.5 J/g or less within a temperature range of from 85° C. to 120° C.

First claim

The invention claimed is:

1. A toner comprising:
an amorphous polyester resin and an easily-compatible latent crystalline polyester resin, wherein each of the two polyester resins is obtained by condensation polymerization of an alcohol component and a carboxylic acid component; and
a release agent,
wherein the amorphous polyester resin comprises at least one member selected from the group consisting of bisphenol A propylene oxide, bisphenol A ethylene oxide, and propylene glycol as the alcohol component, and comprises terephthalic acid as the carboxylic acid component;
wherein the easily-compatible latent crystalline polyester resin comprises 1,6-hexanediol as the alcohol component, and comprises fumaric acid as the carboxylic acid component,
wherein, when the toner is subjected to a dynamic viscoelasticity measurement at a frequency of 6.28 rad/sec to obtain a temperature-dependent curve of loss tangent (tan δ), and the temperature-dependent curve is differentiated one time with temperature, a resulting curve has a maximum value of 0.07 or more and a minimum value of 0.025 or less within a temperature range of from 85° C. to 110° C., and
wherein, when the toner is subjected to a differential scanning calorimetry (DSC), an endothermic amount measured in a first temperature rising in the DSC is 3.5 J/g or less within a temperature range of from 85° C. to 120° C.

2. The toner of claim 1 , wherein the endothermic amount is 3.0 J/g or less.

3. The toner of claim 1 , wherein the maximum value is 0.10 or more and the minimum value is 0.025 or less.

4. The toner of claim 1 , wherein the toner has a glass transition temperature (Tg) of from 45° C. to 60° C.

5. The toner of claim 1 , wherein the toner has a volume average particle diameter of from 4.5 to 7.0 μm.

6. The toner of claim 1 , wherein the amorphous polyester resin and the easily-compatible latent crystalline polyester resin comprise a first polyester resin having a first solubility parameter SP(1), and a second polyester resin having a second solubility parameter SP(2), wherein:
|SP(1)−SP(2)|≤4.5 cal 1/2 /cm 3/2 .

7. The toner of claim 1 , wherein the easily-compatible latent crystalline polyester resin is a polyester synthesized from fumaric acid and 1,6-hexanediol.

8. The toner of claim 1 , further comprising a second amorphous polyester resin.

9. A developer comprising:
the toner of claim 1 ; and
a carrier.

10. A toner storage unit comprising:
a container; and
the toner of claim 1 stored in the container.

11. An image forming apparatus comprising:
an electrostatic latent image bearer;
an electrostatic latent image forming device configured to form an electrostatic latent image on the electrostatic latent image bearer;
a developing device containing the toner of claim 1 , configured to develop the electrostatic latent image on the electrostatic latent image bearer with the toner to form a toner image;
a transfer device configured to transfer the toner image from the electrostatic latent image onto a surface of a recording medium; and
a fixing device configured to fix the toner image on the surface of the recording medium.

12. An image forming method comprising:
forming an electrostatic latent image on an electrostatic latent image bearer;
developing the electrostatic latent image on the electrostatic latent image bearer with the toner of claim 1 to form a toner image;
transferring the toner image from the electrostatic latent image bearer onto a surface of a recording medium; and
fixing the toner image on the surface of the recording medium.

13. A method for producing printed matter, comprising:
forming an electrostatic latent image on an electrostatic latent image bearer;
developing the electrostatic latent image on the electrostatic latent image bearer with the toner of claim 1 to form a toner image;
transferring the toner image from the electrostatic latent image bearer onto a surface of a recording medium; and
fixing the toner image on the surface of the recording medium.

Assignees

• Ogino Kohtaroh
• Yamauchi Yoshitaka
• Kaneko Akihiro
• Suzuki Kazumi
• Nakajima Hisashi
• Ricoh Co Ltd

Inventors

• Ogino Kohtaroh
• Yamauchi Yoshitaka
• Kaneko Akihiro
• Suzuki Kazumi
• Nakajima Hisashi

Classifications

• G03G21/18

  using a processing cartridge {, whereby the process cartridge comprises at least two image processing means in a single unit} · CPC title

• G03G9/08755 Primary

  Polyesters · CPC title

• G03G9/081

  by mixing the toner components in a liquefied state; melt kneading; reactive mixing · CPC title

• G03G15/0806

  on a donor element, e.g. belt, roller (complete developer unit G03G15/0896) · CPC title

• G03G9/08782

  Waxes · CPC title