Toner, developer, toner storage unit, image forming apparatus, and image forming method

Patent metadata

Field	Value
Publication number	US-12204277-B2
Application number	US-202217678125-A
Country	US
Kind code	B2
Filing date	Feb 23, 2022
Priority date	Feb 26, 2021
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

Provided is a toner including toner base particles and resin particles. Each toner base particle includes a binder resin, a colorant, and wax. Each resin particle e has a core-shell structure including a core and a shell, where a glass transition temperature TgA of the shell is higher than a glass transition temperature TgB of the core. A surface of each toner base particle is covered with the resin particles. A storage elastic modulus G′1 of the toner at 70° C. during heating is 1.0×10 5 Pa or greater but 1.0×10 3 Pa or less, and a storage elastic modulus G′2 of the toner at 100° C. during heating is 1.0×10 4 Pa or greater but 5.0×10 4 Pa or less, as the toner is measured by a rheometer.

First claim

What is claimed is:

1. A toner comprising
toner base particles, each of the toner base particles including a binder resin, a colorant, and wax; and
resin particles, each of the resin particles has a core-shell structure including a core and a shell, where a glass transition temperature TgA of the shell is higher than a glass transition temperature TgB of the core, wherein a surface of each of the toner base particles is covered with the resin particles, and
wherein a storage elastic modulus G′1 of the toner at 70° C. during heating is 1.0×10 5 Pa or greater but 1.0×10 6 Pa or less, and a storage elastic modulus G′2 of the toner at 100° C. during heating is 1.0×10 4 Pa or greater but 5.0×10 4 Pa or less, as the toner is measured by a rheometer.

2. The toner according to claim 1 ,
wherein a coverage factor of the toner base particles with the resin particles is 30% or greater but 90% or less.

3. The toner according to claim 2 ,
wherein the coverage factor of the toner base particles with the resin particles is 30% or greater but 70% or less.

4. The toner according to claim 1 ,
wherein the resin particles satisfy TgA−TgB≥10° C., where TgA is a glass transition temperature of the shell of each of the resin particles, and TgB is a glass transition temperature of the core of each of the resin particles.

5. The toner according to claim 1 ,
wherein the resin particles include a styrene-acrylic resin in both the shell and the core of each of the resin particles.

6. The toner according to claim 1 ,
wherein the resin particles have a volume average primary particle diameter of 10 nm or greater but 100 nm or less.

7. The toner according to claim 1 ,
wherein the resin particles have a glass transition temperature Tg of 40° C. or higher but 70° C. or lower.

8. The toner according to claim 1 ,
wherein a standard deviation of distances between the resin particles next to one another present on the surface of each of the toner base particles is 500 nm or less.

9. The toner according to claim 1 ,
wherein a glass transition temperature Tg1st of the toner measured from first heating of differential scanning calorimetry (DSC) of the toner is 20° C. or higher but 50° C. or lower, and
a glass transition temperature Tg1st of a tetrahydrofuran (THF) insoluble component of the toner measured from first heating of differential scanning calorimetry (DSC) of the THF insoluble component is −40° C. or higher but 10° C. or lower.

10. A developer comprising:
a carrier; and
the toner according to claim 1 .

11. A toner storage unit comprising:
the toner according to claim 1 ; and
a unit, in which the toner is stored.

12. 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 device including a toner and configured to develop the electrostatic latent image with the toner to form a visible image;
a transferring unit configured to transfer the visible image onto a recording medium;
a fixing unit configured to fix the transferred visible image on the recording medium; and
a cleaning unit configured to clean the electrostatic latent image bearer,
wherein the toner is the toner according to claim 1 .

13. An image forming method comprising:
forming an electrostatic latent image on an electrostatic latent image bearer;
developing the electrostatic latent image with a toner to form a visible image;
transferring the visible image onto a recording medium;
fixing the transferred visible image on the recording medium; and
cleaning the electrostatic latent image bearer,
wherein the toner is the toner according to claim 1 .

Assignees

• Kamada Yasuo
• Yamada Hiroshi
• Takebayashi Toma
• Takei Akio
• Ricoh Co Ltd

Inventors

• Kamada Yasuo
• Yamada Hiroshi
• Takebayashi Toma
• Takei Akio

Classifications

• G03G9/08711

  with esters of acrylic or methacrylic acid · CPC title

• G03G9/0819

  characterised by the dimensions of the particles · CPC title

• G03G15/0258

  provided with means for the maintenance of the charging apparatus, e.g. cleaning devices, ozone removing devices G03G15/0225, G03G15/0291 takes precedence · CPC title

• G03G9/09364

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• G03G9/09357

  Macromolecular compounds · CPC title