Toner and image forming apparatus

Patent metadata

Field	Value
Publication number	US-9417541-B2
Application number	US-201214112407-A
Country	US
Kind code	B2
Filing date	Apr 25, 2012
Priority date	Apr 26, 2011
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A toner including: toner particles each including a toner base particle and an external additive attached thereon, where the toner base particle includes a binder resin and a colorant, wherein the toner base particles each have protrusions on a surface thereof, an average of lengths of long sides of the protrusions is 0.10 μm or more but less than 0.50 μm, a standard deviation of the lengths of the long sides of the protrusions is 0.2 or less, a coverage rate of the protrusions on the surface of the toner base particle is 10% to 90%, and the external additive includes fine inorganic particles whose surfaces have been treated with an amino group-containing silane coupling agent.

First claim

The invention claimed is:

1. A toner comprising:
toner particles each comprising a toner base particle and an external additive attached thereon,
wherein
the toner base particle comprises a binder resin and a colorant,
the toner base particle has protrusions on a surface thereof,
an average of lengths of long sides of the protrusions is 0.10 μm or more but less than 0.50 μm,
a standard deviation of the lengths of the long sides of the protrusions is 0.2 or less,
a coverage rate of the protrusions on the surface of the toner base particle is from 10% to 90%, and
the external additive comprises fine inorganic particles whose surfaces have been treated with a silane coupling agent comprising an amino group.

2. The toner according to claim 1 , wherein primary particles of the fine inorganic particles have an average particle diameter of 100 nm or less.

3. The toner according to claim 1 , wherein an amount of the fine inorganic particles in the toner is from 0.1% by mass to 2.0% by mass.

4. The toner according to claim 1 , wherein an amount of the fine inorganic particles in the external additive is from 5% by mass to 30% by mass.

5. The toner according to claim 1 , wherein the protrusions comprise a resin, and the resin is obtained by polymerizing a monomer mixture comprising styrene.

6. The toner according to claim 5 , wherein an amount of the resin is from 1% by mass to 20% by mass in the toner.

7. The toner according to claim 1 , wherein the toner has a rate of 1.25 or less, in which the rate is a rate of a volume average particle diameter to a number average particle diameter of the toner.

8. The toner according to claim 1 , wherein the toner has an average sphericity of 0.930 or more.

9. The toner according to claim 1 , wherein the toner base particles are obtained by a method comprising:
producing toner core particles; and
fusing and attaching the protrusions onto surfaces of the toner core particles.

10. An image forming apparatus comprising:
a latent image bearing member which bears a latent image thereon;
a charging unit configured to uniformly charge a surface of the latent image bearing member;
an exposing unit configured to expose the charged surface of the latent image bearing member to light based on image data to form a latent electrostatic image;
a toner which visualizes the latent electrostatic image;
a developing unit configured to supply the toner to develop the latent electrostatic image formed on the surface of the latent image bearing member, to thereby form a visible image on the surface of the latent image bearing member;
a transfer unit configured to transfer, onto an image-receiving medium, the visible image formed on the surface of the latent image bearing member; and
a fixing unit configured to fix the transferred visible image on the image-receiving medium,
wherein the toner comprises:
toner particles each comprising a toner base particle and an external additive attached thereon,
wherein
the toner base particle comprises a binder resin and a colorant,
the toner base particle has protrusions on a surface thereof,
an average of lengths of long sides of the protrusions is 0.10 μm or more but less than 0.50 μm,
a standard deviation of the lengths of the long sides of the protrusions is 0.2 or less,
a coverage rate of the protrusions on the surface of the toner base particle is from 10% to 90%, and
the external additive comprises fine inorganic particles whose surfaces have been treated with a silane coupling agent comprising an amino group.

11. A process cartridge comprising:
a latent image bearing member,
a developing unit configured to develop, with a toner, a latent electrostatic image formed on a surface of the latent image bearing member to form a visible image,
the latent image bearing member and the developing unit being integrally supported in the process cartridge which is mounted detachably to an image forming apparatus,
wherein the toner comprises:
toner particles each comprising a toner base particle and an external additive attached thereon,
wherein
the toner base particle comprises a binder resin and a colorant,
the toner base particle has protrusions on a surface thereof,
an average of lengths of long sides of the protrusions is 0.10 μm or more but less than 0.50 μm,
a standard deviation of the lengths of the long sides of the protrusions is 0.2 or less,
a coverage rate of the protrusions on the surface of the toner base particle is from 10% to 90%, and
the external additive comprises fine inorganic particles whose surfaces have been treated with a silane coupling agent comprising an amino group.

12. The apparatus according to claim 10 , wherein primary particles of the fine inorganic particles have an average particle diameter of 100 nm or less.

13. The apparatus according to claim 10 , wherein an amount of the fine inorganic particles in the toner is from 0.1% by mass to 2.0% by mass.

14. The apparatus according to claim 10 , wherein an amount of the fine inorganic particles in the external additive is from 5% by mass to 30% by mass.

15. The apparatus according to claim 10 , wherein the protrusions comprise a resin, and the resin is obtained by polymerizing a monomer mixture comprising styrene.

16. The apparatus according to claim 10 , wherein an amount of the resin is from 1% by mass to 20% by mass in the toner.

17. The process cartridge according to claim 11 , wherein primary particles of the fine inorganic particles have an average particle diameter of 100 nm or less.

18. The process cartridge according to claim 11 , wherein an amount of the fine inorganic particles in the toner is from 0.1% by mass to 2.0% by mass.

19. The process cartridge according to claim 11 , wherein an amount of the fine inorganic particles in the external additive is from 5% by mass to 30% by mass.

20. The process cartridge according to claim 11 , wherein the protrusions comprise a resin, and the resin is obtained by polymerizing a monomer mixture comprising styrene.

Assignees

• Ishikawa Yoshimichi
• Kadota Takuya
• Mikuriya Yoshihiro
• Nozaki Tsuyoshi
• Fuwa Kazuoki
• Fukao Tomohiro
• Miki Tomoharu
• Ricoh Co Ltd

Inventors

• Ishikawa Yoshimichi
• Kadota Takuya
• Mikuriya Yoshihiro
• Nozaki Tsuyoshi
• Fuwa Kazuoki
• Fukao Tomohiro
• Miki Tomoharu

Classifications

• G03G9/0804

  whereby the components are brought together in a liquid dispersing medium · CPC title

• G03G9/09307

  specified by the shell material · CPC title

• G03G9/0819

  characterised by the dimensions of the particles · CPC title

• G03G9/09321

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

• G03G9/0806

  whereby chemical synthesis of at least one of the toner components takes place · CPC title